io_uring: move to separate directory

In preparation for splitting io_uring up a bit, move it into its own
top level directory. It didn't really belong in fs/ anyway, as it's
not a file system only API.

This adds io_uring/ and moves the core files in there, and updates the
MAINTAINERS file for the new location.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

4 files changed, 14823 insertions, 0 deletions

diff --git a/io_uring/Makefile b/io_uring/Makefile
new file mode 100644
index 000000000000..3680425df947
--- /dev/null
+++ b/io_uring/Makefile
@@ -0,0 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for io_uring
+
+obj-$(CONFIG_IO_URING)		+= io_uring.o
+obj-$(CONFIG_IO_WQ)		+= io-wq.o
diff --git a/io_uring/io-wq.c b/io_uring/io-wq.c
new file mode 100644
index 000000000000..824623bcf1a5
--- /dev/null
+++ b/io_uring/io-wq.c
@@ -0,0 +1,1424 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Basic worker thread pool for io_uring
+ *
+ * Copyright (C) 2019 Jens Axboe
+ *
+ */
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/errno.h>
+#include <linux/sched/signal.h>
+#include <linux/percpu.h>
+#include <linux/slab.h>
+#include <linux/rculist_nulls.h>
+#include <linux/cpu.h>
+#include <linux/task_work.h>
+#include <linux/audit.h>
+#include <uapi/linux/io_uring.h>
+
+#include "io-wq.h"
+
+#define WORKER_IDLE_TIMEOUT	(5 * HZ)
+
+enum {
+	IO_WORKER_F_UP		= 1,	/* up and active */
+	IO_WORKER_F_RUNNING	= 2,	/* account as running */
+	IO_WORKER_F_FREE	= 4,	/* worker on free list */
+	IO_WORKER_F_BOUND	= 8,	/* is doing bounded work */
+};
+
+enum {
+	IO_WQ_BIT_EXIT		= 0,	/* wq exiting */
+};
+
+enum {
+	IO_ACCT_STALLED_BIT	= 0,	/* stalled on hash */
+};
+
+/*
+ * One for each thread in a wqe pool
+ */
+struct io_worker {
+	refcount_t ref;
+	unsigned flags;
+	struct hlist_nulls_node nulls_node;
+	struct list_head all_list;
+	struct task_struct *task;
+	struct io_wqe *wqe;
+
+	struct io_wq_work *cur_work;
+	struct io_wq_work *next_work;
+	raw_spinlock_t lock;
+
+	struct completion ref_done;
+
+	unsigned long create_state;
+	struct callback_head create_work;
+	int create_index;
+
+	union {
+		struct rcu_head rcu;
+		struct work_struct work;
+	};
+};
+
+#if BITS_PER_LONG == 64
+#define IO_WQ_HASH_ORDER	6
+#else
+#define IO_WQ_HASH_ORDER	5
+#endif
+
+#define IO_WQ_NR_HASH_BUCKETS	(1u << IO_WQ_HASH_ORDER)
+
+struct io_wqe_acct {
+	unsigned nr_workers;
+	unsigned max_workers;
+	int index;
+	atomic_t nr_running;
+	raw_spinlock_t lock;
+	struct io_wq_work_list work_list;
+	unsigned long flags;
+};
+
+enum {
+	IO_WQ_ACCT_BOUND,
+	IO_WQ_ACCT_UNBOUND,
+	IO_WQ_ACCT_NR,
+};
+
+/*
+ * Per-node worker thread pool
+ */
+struct io_wqe {
+	raw_spinlock_t lock;
+	struct io_wqe_acct acct[IO_WQ_ACCT_NR];
+
+	int node;
+
+	struct hlist_nulls_head free_list;
+	struct list_head all_list;
+
+	struct wait_queue_entry wait;
+
+	struct io_wq *wq;
+	struct io_wq_work *hash_tail[IO_WQ_NR_HASH_BUCKETS];
+
+	cpumask_var_t cpu_mask;
+};
+
+/*
+ * Per io_wq state
+  */
+struct io_wq {
+	unsigned long state;
+
+	free_work_fn *free_work;
+	io_wq_work_fn *do_work;
+
+	struct io_wq_hash *hash;
+
+	atomic_t worker_refs;
+	struct completion worker_done;
+
+	struct hlist_node cpuhp_node;
+
+	struct task_struct *task;
+
+	struct io_wqe *wqes[];
+};
+
+static enum cpuhp_state io_wq_online;
+
+struct io_cb_cancel_data {
+	work_cancel_fn *fn;
+	void *data;
+	int nr_running;
+	int nr_pending;
+	bool cancel_all;
+};
+
+static bool create_io_worker(struct io_wq *wq, struct io_wqe *wqe, int index);
+static void io_wqe_dec_running(struct io_worker *worker);
+static bool io_acct_cancel_pending_work(struct io_wqe *wqe,
+					struct io_wqe_acct *acct,
+					struct io_cb_cancel_data *match);
+static void create_worker_cb(struct callback_head *cb);
+static void io_wq_cancel_tw_create(struct io_wq *wq);
+
+static bool io_worker_get(struct io_worker *worker)
+{
+	return refcount_inc_not_zero(&worker->ref);
+}
+
+static void io_worker_release(struct io_worker *worker)
+{
+	if (refcount_dec_and_test(&worker->ref))
+		complete(&worker->ref_done);
+}
+
+static inline struct io_wqe_acct *io_get_acct(struct io_wqe *wqe, bool bound)
+{
+	return &wqe->acct[bound ? IO_WQ_ACCT_BOUND : IO_WQ_ACCT_UNBOUND];
+}
+
+static inline struct io_wqe_acct *io_work_get_acct(struct io_wqe *wqe,
+						   struct io_wq_work *work)
+{
+	return io_get_acct(wqe, !(work->flags & IO_WQ_WORK_UNBOUND));
+}
+
+static inline struct io_wqe_acct *io_wqe_get_acct(struct io_worker *worker)
+{
+	return io_get_acct(worker->wqe, worker->flags & IO_WORKER_F_BOUND);
+}
+
+static void io_worker_ref_put(struct io_wq *wq)
+{
+	if (atomic_dec_and_test(&wq->worker_refs))
+		complete(&wq->worker_done);
+}
+
+static void io_worker_cancel_cb(struct io_worker *worker)
+{
+	struct io_wqe_acct *acct = io_wqe_get_acct(worker);
+	struct io_wqe *wqe = worker->wqe;
+	struct io_wq *wq = wqe->wq;
+
+	atomic_dec(&acct->nr_running);
+	raw_spin_lock(&worker->wqe->lock);
+	acct->nr_workers--;
+	raw_spin_unlock(&worker->wqe->lock);
+	io_worker_ref_put(wq);
+	clear_bit_unlock(0, &worker->create_state);
+	io_worker_release(worker);
+}
+
+static bool io_task_worker_match(struct callback_head *cb, void *data)
+{
+	struct io_worker *worker;
+
+	if (cb->func != create_worker_cb)
+		return false;
+	worker = container_of(cb, struct io_worker, create_work);
+	return worker == data;
+}
+
+static void io_worker_exit(struct io_worker *worker)
+{
+	struct io_wqe *wqe = worker->wqe;
+	struct io_wq *wq = wqe->wq;
+
+	while (1) {
+		struct callback_head *cb = task_work_cancel_match(wq->task,
+						io_task_worker_match, worker);
+
+		if (!cb)
+			break;
+		io_worker_cancel_cb(worker);
+	}
+
+	io_worker_release(worker);
+	wait_for_completion(&worker->ref_done);
+
+	raw_spin_lock(&wqe->lock);
+	if (worker->flags & IO_WORKER_F_FREE)
+		hlist_nulls_del_rcu(&worker->nulls_node);
+	list_del_rcu(&worker->all_list);
+	raw_spin_unlock(&wqe->lock);
+	io_wqe_dec_running(worker);
+	worker->flags = 0;
+	preempt_disable();
+	current->flags &= ~PF_IO_WORKER;
+	preempt_enable();
+
+	kfree_rcu(worker, rcu);
+	io_worker_ref_put(wqe->wq);
+	do_exit(0);
+}
+
+static inline bool io_acct_run_queue(struct io_wqe_acct *acct)
+{
+	bool ret = false;
+
+	raw_spin_lock(&acct->lock);
+	if (!wq_list_empty(&acct->work_list) &&
+	    !test_bit(IO_ACCT_STALLED_BIT, &acct->flags))
+		ret = true;
+	raw_spin_unlock(&acct->lock);
+
+	return ret;
+}
+
+/*
+ * Check head of free list for an available worker. If one isn't available,
+ * caller must create one.
+ */
+static bool io_wqe_activate_free_worker(struct io_wqe *wqe,
+					struct io_wqe_acct *acct)
+	__must_hold(RCU)
+{
+	struct hlist_nulls_node *n;
+	struct io_worker *worker;
+
+	/*
+	 * Iterate free_list and see if we can find an idle worker to
+	 * activate. If a given worker is on the free_list but in the process
+	 * of exiting, keep trying.
+	 */
+	hlist_nulls_for_each_entry_rcu(worker, n, &wqe->free_list, nulls_node) {
+		if (!io_worker_get(worker))
+			continue;
+		if (io_wqe_get_acct(worker) != acct) {
+			io_worker_release(worker);
+			continue;
+		}
+		if (wake_up_process(worker->task)) {
+			io_worker_release(worker);
+			return true;
+		}
+		io_worker_release(worker);
+	}
+
+	return false;
+}
+
+/*
+ * We need a worker. If we find a free one, we're good. If not, and we're
+ * below the max number of workers, create one.
+ */
+static bool io_wqe_create_worker(struct io_wqe *wqe, struct io_wqe_acct *acct)
+{
+	/*
+	 * Most likely an attempt to queue unbounded work on an io_wq that
+	 * wasn't setup with any unbounded workers.
+	 */
+	if (unlikely(!acct->max_workers))
+		pr_warn_once("io-wq is not configured for unbound workers");
+
+	raw_spin_lock(&wqe->lock);
+	if (acct->nr_workers >= acct->max_workers) {
+		raw_spin_unlock(&wqe->lock);
+		return true;
+	}
+	acct->nr_workers++;
+	raw_spin_unlock(&wqe->lock);
+	atomic_inc(&acct->nr_running);
+	atomic_inc(&wqe->wq->worker_refs);
+	return create_io_worker(wqe->wq, wqe, acct->index);
+}
+
+static void io_wqe_inc_running(struct io_worker *worker)
+{
+	struct io_wqe_acct *acct = io_wqe_get_acct(worker);
+
+	atomic_inc(&acct->nr_running);
+}
+
+static void create_worker_cb(struct callback_head *cb)
+{
+	struct io_worker *worker;
+	struct io_wq *wq;
+	struct io_wqe *wqe;
+	struct io_wqe_acct *acct;
+	bool do_create = false;
+
+	worker = container_of(cb, struct io_worker, create_work);
+	wqe = worker->wqe;
+	wq = wqe->wq;
+	acct = &wqe->acct[worker->create_index];
+	raw_spin_lock(&wqe->lock);
+	if (acct->nr_workers < acct->max_workers) {
+		acct->nr_workers++;
+		do_create = true;
+	}
+	raw_spin_unlock(&wqe->lock);
+	if (do_create) {
+		create_io_worker(wq, wqe, worker->create_index);
+	} else {
+		atomic_dec(&acct->nr_running);
+		io_worker_ref_put(wq);
+	}
+	clear_bit_unlock(0, &worker->create_state);
+	io_worker_release(worker);
+}
+
+static bool io_queue_worker_create(struct io_worker *worker,
+				   struct io_wqe_acct *acct,
+				   task_work_func_t func)
+{
+	struct io_wqe *wqe = worker->wqe;
+	struct io_wq *wq = wqe->wq;
+
+	/* raced with exit, just ignore create call */
+	if (test_bit(IO_WQ_BIT_EXIT, &wq->state))
+		goto fail;
+	if (!io_worker_get(worker))
+		goto fail;
+	/*
+	 * create_state manages ownership of create_work/index. We should
+	 * only need one entry per worker, as the worker going to sleep
+	 * will trigger the condition, and waking will clear it once it
+	 * runs the task_work.
+	 */
+	if (test_bit(0, &worker->create_state) ||
+	    test_and_set_bit_lock(0, &worker->create_state))
+		goto fail_release;
+
+	atomic_inc(&wq->worker_refs);
+	init_task_work(&worker->create_work, func);
+	worker->create_index = acct->index;
+	if (!task_work_add(wq->task, &worker->create_work, TWA_SIGNAL)) {
+		/*
+		 * EXIT may have been set after checking it above, check after
+		 * adding the task_work and remove any creation item if it is
+		 * now set. wq exit does that too, but we can have added this
+		 * work item after we canceled in io_wq_exit_workers().
+		 */
+		if (test_bit(IO_WQ_BIT_EXIT, &wq->state))
+			io_wq_cancel_tw_create(wq);
+		io_worker_ref_put(wq);
+		return true;
+	}
+	io_worker_ref_put(wq);
+	clear_bit_unlock(0, &worker->create_state);
+fail_release:
+	io_worker_release(worker);
+fail:
+	atomic_dec(&acct->nr_running);
+	io_worker_ref_put(wq);
+	return false;
+}
+
+static void io_wqe_dec_running(struct io_worker *worker)
+{
+	struct io_wqe_acct *acct = io_wqe_get_acct(worker);
+	struct io_wqe *wqe = worker->wqe;
+
+	if (!(worker->flags & IO_WORKER_F_UP))
+		return;
+
+	if (!atomic_dec_and_test(&acct->nr_running))
+		return;
+	if (!io_acct_run_queue(acct))
+		return;
+
+	atomic_inc(&acct->nr_running);
+	atomic_inc(&wqe->wq->worker_refs);
+	io_queue_worker_create(worker, acct, create_worker_cb);
+}
+
+/*
+ * Worker will start processing some work. Move it to the busy list, if
+ * it's currently on the freelist
+ */
+static void __io_worker_busy(struct io_wqe *wqe, struct io_worker *worker)
+{
+	if (worker->flags & IO_WORKER_F_FREE) {
+		worker->flags &= ~IO_WORKER_F_FREE;
+		raw_spin_lock(&wqe->lock);
+		hlist_nulls_del_init_rcu(&worker->nulls_node);
+		raw_spin_unlock(&wqe->lock);
+	}
+}
+
+/*
+ * No work, worker going to sleep. Move to freelist, and unuse mm if we
+ * have one attached. Dropping the mm may potentially sleep, so we drop
+ * the lock in that case and return success. Since the caller has to
+ * retry the loop in that case (we changed task state), we don't regrab
+ * the lock if we return success.
+ */
+static void __io_worker_idle(struct io_wqe *wqe, struct io_worker *worker)
+	__must_hold(wqe->lock)
+{
+	if (!(worker->flags & IO_WORKER_F_FREE)) {
+		worker->flags |= IO_WORKER_F_FREE;
+		hlist_nulls_add_head_rcu(&worker->nulls_node, &wqe->free_list);
+	}
+}
+
+static inline unsigned int io_get_work_hash(struct io_wq_work *work)
+{
+	return work->flags >> IO_WQ_HASH_SHIFT;
+}
+
+static bool io_wait_on_hash(struct io_wqe *wqe, unsigned int hash)
+{
+	struct io_wq *wq = wqe->wq;
+	bool ret = false;
+
+	spin_lock_irq(&wq->hash->wait.lock);
+	if (list_empty(&wqe->wait.entry)) {
+		__add_wait_queue(&wq->hash->wait, &wqe->wait);
+		if (!test_bit(hash, &wq->hash->map)) {
+			__set_current_state(TASK_RUNNING);
+			list_del_init(&wqe->wait.entry);
+			ret = true;
+		}
+	}
+	spin_unlock_irq(&wq->hash->wait.lock);
+	return ret;
+}
+
+static struct io_wq_work *io_get_next_work(struct io_wqe_acct *acct,
+					   struct io_worker *worker)
+	__must_hold(acct->lock)
+{
+	struct io_wq_work_node *node, *prev;
+	struct io_wq_work *work, *tail;
+	unsigned int stall_hash = -1U;
+	struct io_wqe *wqe = worker->wqe;
+
+	wq_list_for_each(node, prev, &acct->work_list) {
+		unsigned int hash;
+
+		work = container_of(node, struct io_wq_work, list);
+
+		/* not hashed, can run anytime */
+		if (!io_wq_is_hashed(work)) {
+			wq_list_del(&acct->work_list, node, prev);
+			return work;
+		}
+
+		hash = io_get_work_hash(work);
+		/* all items with this hash lie in [work, tail] */
+		tail = wqe->hash_tail[hash];
+
+		/* hashed, can run if not already running */
+		if (!test_and_set_bit(hash, &wqe->wq->hash->map)) {
+			wqe->hash_tail[hash] = NULL;
+			wq_list_cut(&acct->work_list, &tail->list, prev);
+			return work;
+		}
+		if (stall_hash == -1U)
+			stall_hash = hash;
+		/* fast forward to a next hash, for-each will fix up @prev */
+		node = &tail->list;
+	}
+
+	if (stall_hash != -1U) {
+		bool unstalled;
+
+		/*
+		 * Set this before dropping the lock to avoid racing with new
+		 * work being added and clearing the stalled bit.
+		 */
+		set_bit(IO_ACCT_STALLED_BIT, &acct->flags);
+		raw_spin_unlock(&acct->lock);
+		unstalled = io_wait_on_hash(wqe, stall_hash);
+		raw_spin_lock(&acct->lock);
+		if (unstalled) {
+			clear_bit(IO_ACCT_STALLED_BIT, &acct->flags);
+			if (wq_has_sleeper(&wqe->wq->hash->wait))
+				wake_up(&wqe->wq->hash->wait);
+		}
+	}
+
+	return NULL;
+}
+
+static bool io_flush_signals(void)
+{
+	if (unlikely(test_thread_flag(TIF_NOTIFY_SIGNAL))) {
+		__set_current_state(TASK_RUNNING);
+		clear_notify_signal();
+		if (task_work_pending(current))
+			task_work_run();
+		return true;
+	}
+	return false;
+}
+
+static void io_assign_current_work(struct io_worker *worker,
+				   struct io_wq_work *work)
+{
+	if (work) {
+		io_flush_signals();
+		cond_resched();
+	}
+
+	raw_spin_lock(&worker->lock);
+	worker->cur_work = work;
+	worker->next_work = NULL;
+	raw_spin_unlock(&worker->lock);
+}
+
+static void io_wqe_enqueue(struct io_wqe *wqe, struct io_wq_work *work);
+
+static void io_worker_handle_work(struct io_worker *worker)
+{
+	struct io_wqe_acct *acct = io_wqe_get_acct(worker);
+	struct io_wqe *wqe = worker->wqe;
+	struct io_wq *wq = wqe->wq;
+	bool do_kill = test_bit(IO_WQ_BIT_EXIT, &wq->state);
+
+	do {
+		struct io_wq_work *work;
+
+		/*
+		 * If we got some work, mark us as busy. If we didn't, but
+		 * the list isn't empty, it means we stalled on hashed work.
+		 * Mark us stalled so we don't keep looking for work when we
+		 * can't make progress, any work completion or insertion will
+		 * clear the stalled flag.
+		 */
+		raw_spin_lock(&acct->lock);
+		work = io_get_next_work(acct, worker);
+		raw_spin_unlock(&acct->lock);
+		if (work) {
+			__io_worker_busy(wqe, worker);
+
+			/*
+			 * Make sure cancelation can find this, even before
+			 * it becomes the active work. That avoids a window
+			 * where the work has been removed from our general
+			 * work list, but isn't yet discoverable as the
+			 * current work item for this worker.
+			 */
+			raw_spin_lock(&worker->lock);
+			worker->next_work = work;
+			raw_spin_unlock(&worker->lock);
+		} else {
+			break;
+		}
+		io_assign_current_work(worker, work);
+		__set_current_state(TASK_RUNNING);
+
+		/* handle a whole dependent link */
+		do {
+			struct io_wq_work *next_hashed, *linked;
+			unsigned int hash = io_get_work_hash(work);
+
+			next_hashed = wq_next_work(work);
+
+			if (unlikely(do_kill) && (work->flags & IO_WQ_WORK_UNBOUND))
+				work->flags |= IO_WQ_WORK_CANCEL;
+			wq->do_work(work);
+			io_assign_current_work(worker, NULL);
+
+			linked = wq->free_work(work);
+			work = next_hashed;
+			if (!work && linked && !io_wq_is_hashed(linked)) {
+				work = linked;
+				linked = NULL;
+			}
+			io_assign_current_work(worker, work);
+			if (linked)
+				io_wqe_enqueue(wqe, linked);
+
+			if (hash != -1U && !next_hashed) {
+				/* serialize hash clear with wake_up() */
+				spin_lock_irq(&wq->hash->wait.lock);
+				clear_bit(hash, &wq->hash->map);
+				clear_bit(IO_ACCT_STALLED_BIT, &acct->flags);
+				spin_unlock_irq(&wq->hash->wait.lock);
+				if (wq_has_sleeper(&wq->hash->wait))
+					wake_up(&wq->hash->wait);
+			}
+		} while (work);
+	} while (1);
+}
+
+static int io_wqe_worker(void *data)
+{
+	struct io_worker *worker = data;
+	struct io_wqe_acct *acct = io_wqe_get_acct(worker);
+	struct io_wqe *wqe = worker->wqe;
+	struct io_wq *wq = wqe->wq;
+	bool last_timeout = false;
+	char buf[TASK_COMM_LEN];
+
+	worker->flags |= (IO_WORKER_F_UP | IO_WORKER_F_RUNNING);
+
+	snprintf(buf, sizeof(buf), "iou-wrk-%d", wq->task->pid);
+	set_task_comm(current, buf);
+
+	audit_alloc_kernel(current);
+
+	while (!test_bit(IO_WQ_BIT_EXIT, &wq->state)) {
+		long ret;
+
+		set_current_state(TASK_INTERRUPTIBLE);
+		while (io_acct_run_queue(acct))
+			io_worker_handle_work(worker);
+
+		raw_spin_lock(&wqe->lock);
+		/* timed out, exit unless we're the last worker */
+		if (last_timeout && acct->nr_workers > 1) {
+			acct->nr_workers--;
+			raw_spin_unlock(&wqe->lock);
+			__set_current_state(TASK_RUNNING);
+			break;
+		}
+		last_timeout = false;
+		__io_worker_idle(wqe, worker);
+		raw_spin_unlock(&wqe->lock);
+		if (io_flush_signals())
+			continue;
+		ret = schedule_timeout(WORKER_IDLE_TIMEOUT);
+		if (signal_pending(current)) {
+			struct ksignal ksig;
+
+			if (!get_signal(&ksig))
+				continue;
+			break;
+		}
+		last_timeout = !ret;
+	}
+
+	if (test_bit(IO_WQ_BIT_EXIT, &wq->state))
+		io_worker_handle_work(worker);
+
+	audit_free(current);
+	io_worker_exit(worker);
+	return 0;
+}
+
+/*
+ * Called when a worker is scheduled in. Mark us as currently running.
+ */
+void io_wq_worker_running(struct task_struct *tsk)
+{
+	struct io_worker *worker = tsk->worker_private;
+
+	if (!worker)
+		return;
+	if (!(worker->flags & IO_WORKER_F_UP))
+		return;
+	if (worker->flags & IO_WORKER_F_RUNNING)
+		return;
+	worker->flags |= IO_WORKER_F_RUNNING;
+	io_wqe_inc_running(worker);
+}
+
+/*
+ * Called when worker is going to sleep. If there are no workers currently
+ * running and we have work pending, wake up a free one or create a new one.
+ */
+void io_wq_worker_sleeping(struct task_struct *tsk)
+{
+	struct io_worker *worker = tsk->worker_private;
+
+	if (!worker)
+		return;
+	if (!(worker->flags & IO_WORKER_F_UP))
+		return;
+	if (!(worker->flags & IO_WORKER_F_RUNNING))
+		return;
+
+	worker->flags &= ~IO_WORKER_F_RUNNING;
+	io_wqe_dec_running(worker);
+}
+
+static void io_init_new_worker(struct io_wqe *wqe, struct io_worker *worker,
+			       struct task_struct *tsk)
+{
+	tsk->worker_private = worker;
+	worker->task = tsk;
+	set_cpus_allowed_ptr(tsk, wqe->cpu_mask);
+	tsk->flags |= PF_NO_SETAFFINITY;
+
+	raw_spin_lock(&wqe->lock);
+	hlist_nulls_add_head_rcu(&worker->nulls_node, &wqe->free_list);
+	list_add_tail_rcu(&worker->all_list, &wqe->all_list);
+	worker->flags |= IO_WORKER_F_FREE;
+	raw_spin_unlock(&wqe->lock);
+	wake_up_new_task(tsk);
+}
+
+static bool io_wq_work_match_all(struct io_wq_work *work, void *data)
+{
+	return true;
+}
+
+static inline bool io_should_retry_thread(long err)
+{
+	/*
+	 * Prevent perpetual task_work retry, if the task (or its group) is
+	 * exiting.
+	 */
+	if (fatal_signal_pending(current))
+		return false;
+
+	switch (err) {
+	case -EAGAIN:
+	case -ERESTARTSYS:
+	case -ERESTARTNOINTR:
+	case -ERESTARTNOHAND:
+		return true;
+	default:
+		return false;
+	}
+}
+
+static void create_worker_cont(struct callback_head *cb)
+{
+	struct io_worker *worker;
+	struct task_struct *tsk;
+	struct io_wqe *wqe;
+
+	worker = container_of(cb, struct io_worker, create_work);
+	clear_bit_unlock(0, &worker->create_state);
+	wqe = worker->wqe;
+	tsk = create_io_thread(io_wqe_worker, worker, wqe->node);
+	if (!IS_ERR(tsk)) {
+		io_init_new_worker(wqe, worker, tsk);
+		io_worker_release(worker);
+		return;
+	} else if (!io_should_retry_thread(PTR_ERR(tsk))) {
+		struct io_wqe_acct *acct = io_wqe_get_acct(worker);
+
+		atomic_dec(&acct->nr_running);
+		raw_spin_lock(&wqe->lock);
+		acct->nr_workers--;
+		if (!acct->nr_workers) {
+			struct io_cb_cancel_data match = {
+				.fn		= io_wq_work_match_all,
+				.cancel_all	= true,
+			};
+
+			raw_spin_unlock(&wqe->lock);
+			while (io_acct_cancel_pending_work(wqe, acct, &match))
+				;
+		} else {
+			raw_spin_unlock(&wqe->lock);
+		}
+		io_worker_ref_put(wqe->wq);
+		kfree(worker);
+		return;
+	}
+
+	/* re-create attempts grab a new worker ref, drop the existing one */
+	io_worker_release(worker);
+	schedule_work(&worker->work);
+}
+
+static void io_workqueue_create(struct work_struct *work)
+{
+	struct io_worker *worker = container_of(work, struct io_worker, work);
+	struct io_wqe_acct *acct = io_wqe_get_acct(worker);
+
+	if (!io_queue_worker_create(worker, acct, create_worker_cont))
+		kfree(worker);
+}
+
+static bool create_io_worker(struct io_wq *wq, struct io_wqe *wqe, int index)
+{
+	struct io_wqe_acct *acct = &wqe->acct[index];
+	struct io_worker *worker;
+	struct task_struct *tsk;
+
+	__set_current_state(TASK_RUNNING);
+
+	worker = kzalloc_node(sizeof(*worker), GFP_KERNEL, wqe->node);
+	if (!worker) {
+fail:
+		atomic_dec(&acct->nr_running);
+		raw_spin_lock(&wqe->lock);
+		acct->nr_workers--;
+		raw_spin_unlock(&wqe->lock);
+		io_worker_ref_put(wq);
+		return false;
+	}
+
+	refcount_set(&worker->ref, 1);
+	worker->wqe = wqe;
+	raw_spin_lock_init(&worker->lock);
+	init_completion(&worker->ref_done);
+
+	if (index == IO_WQ_ACCT_BOUND)
+		worker->flags |= IO_WORKER_F_BOUND;
+
+	tsk = create_io_thread(io_wqe_worker, worker, wqe->node);
+	if (!IS_ERR(tsk)) {
+		io_init_new_worker(wqe, worker, tsk);
+	} else if (!io_should_retry_thread(PTR_ERR(tsk))) {
+		kfree(worker);
+		goto fail;
+	} else {
+		INIT_WORK(&worker->work, io_workqueue_create);
+		schedule_work(&worker->work);
+	}
+
+	return true;
+}
+
+/*
+ * Iterate the passed in list and call the specific function for each
+ * worker that isn't exiting
+ */
+static bool io_wq_for_each_worker(struct io_wqe *wqe,
+				  bool (*func)(struct io_worker *, void *),
+				  void *data)
+{
+	struct io_worker *worker;
+	bool ret = false;
+
+	list_for_each_entry_rcu(worker, &wqe->all_list, all_list) {
+		if (io_worker_get(worker)) {
+			/* no task if node is/was offline */
+			if (worker->task)
+				ret = func(worker, data);
+			io_worker_release(worker);
+			if (ret)
+				break;
+		}
+	}
+
+	return ret;
+}
+
+static bool io_wq_worker_wake(struct io_worker *worker, void *data)
+{
+	__set_notify_signal(worker->task);
+	wake_up_process(worker->task);
+	return false;
+}
+
+static void io_run_cancel(struct io_wq_work *work, struct io_wqe *wqe)
+{
+	struct io_wq *wq = wqe->wq;
+
+	do {
+		work->flags |= IO_WQ_WORK_CANCEL;
+		wq->do_work(work);
+		work = wq->free_work(work);
+	} while (work);
+}
+
+static void io_wqe_insert_work(struct io_wqe *wqe, struct io_wq_work *work)
+{
+	struct io_wqe_acct *acct = io_work_get_acct(wqe, work);
+	unsigned int hash;
+	struct io_wq_work *tail;
+
+	if (!io_wq_is_hashed(work)) {
+append:
+		wq_list_add_tail(&work->list, &acct->work_list);
+		return;
+	}
+
+	hash = io_get_work_hash(work);
+	tail = wqe->hash_tail[hash];
+	wqe->hash_tail[hash] = work;
+	if (!tail)
+		goto append;
+
+	wq_list_add_after(&work->list, &tail->list, &acct->work_list);
+}
+
+static bool io_wq_work_match_item(struct io_wq_work *work, void *data)
+{
+	return work == data;
+}
+
+static void io_wqe_enqueue(struct io_wqe *wqe, struct io_wq_work *work)
+{
+	struct io_wqe_acct *acct = io_work_get_acct(wqe, work);
+	struct io_cb_cancel_data match;
+	unsigned work_flags = work->flags;
+	bool do_create;
+
+	/*
+	 * If io-wq is exiting for this task, or if the request has explicitly
+	 * been marked as one that should not get executed, cancel it here.
+	 */
+	if (test_bit(IO_WQ_BIT_EXIT, &wqe->wq->state) ||
+	    (work->flags & IO_WQ_WORK_CANCEL)) {
+		io_run_cancel(work, wqe);
+		return;
+	}
+
+	raw_spin_lock(&acct->lock);
+	io_wqe_insert_work(wqe, work);
+	clear_bit(IO_ACCT_STALLED_BIT, &acct->flags);
+	raw_spin_unlock(&acct->lock);
+
+	raw_spin_lock(&wqe->lock);
+	rcu_read_lock();
+	do_create = !io_wqe_activate_free_worker(wqe, acct);
+	rcu_read_unlock();
+
+	raw_spin_unlock(&wqe->lock);
+
+	if (do_create && ((work_flags & IO_WQ_WORK_CONCURRENT) ||
+	    !atomic_read(&acct->nr_running))) {
+		bool did_create;
+
+		did_create = io_wqe_create_worker(wqe, acct);
+		if (likely(did_create))
+			return;
+
+		raw_spin_lock(&wqe->lock);
+		if (acct->nr_workers) {
+			raw_spin_unlock(&wqe->lock);
+			return;
+		}
+		raw_spin_unlock(&wqe->lock);
+
+		/* fatal condition, failed to create the first worker */
+		match.fn		= io_wq_work_match_item,
+		match.data		= work,
+		match.cancel_all	= false,
+
+		io_acct_cancel_pending_work(wqe, acct, &match);
+	}
+}
+
+void io_wq_enqueue(struct io_wq *wq, struct io_wq_work *work)
+{
+	struct io_wqe *wqe = wq->wqes[numa_node_id()];
+
+	io_wqe_enqueue(wqe, work);
+}
+
+/*
+ * Work items that hash to the same value will not be done in parallel.
+ * Used to limit concurrent writes, generally hashed by inode.
+ */
+void io_wq_hash_work(struct io_wq_work *work, void *val)
+{
+	unsigned int bit;
+
+	bit = hash_ptr(val, IO_WQ_HASH_ORDER);
+	work->flags |= (IO_WQ_WORK_HASHED | (bit << IO_WQ_HASH_SHIFT));
+}
+
+static bool __io_wq_worker_cancel(struct io_worker *worker,
+				  struct io_cb_cancel_data *match,
+				  struct io_wq_work *work)
+{
+	if (work && match->fn(work, match->data)) {
+		work->flags |= IO_WQ_WORK_CANCEL;
+		__set_notify_signal(worker->task);
+		return true;
+	}
+
+	return false;
+}
+
+static bool io_wq_worker_cancel(struct io_worker *worker, void *data)
+{
+	struct io_cb_cancel_data *match = data;
+
+	/*
+	 * Hold the lock to avoid ->cur_work going out of scope, caller
+	 * may dereference the passed in work.
+	 */
+	raw_spin_lock(&worker->lock);
+	if (__io_wq_worker_cancel(worker, match, worker->cur_work) ||
+	    __io_wq_worker_cancel(worker, match, worker->next_work))
+		match->nr_running++;
+	raw_spin_unlock(&worker->lock);
+
+	return match->nr_running && !match->cancel_all;
+}
+
+static inline void io_wqe_remove_pending(struct io_wqe *wqe,
+					 struct io_wq_work *work,
+					 struct io_wq_work_node *prev)
+{
+	struct io_wqe_acct *acct = io_work_get_acct(wqe, work);
+	unsigned int hash = io_get_work_hash(work);
+	struct io_wq_work *prev_work = NULL;
+
+	if (io_wq_is_hashed(work) && work == wqe->hash_tail[hash]) {
+		if (prev)
+			prev_work = container_of(prev, struct io_wq_work, list);
+		if (prev_work && io_get_work_hash(prev_work) == hash)
+			wqe->hash_tail[hash] = prev_work;
+		else
+			wqe->hash_tail[hash] = NULL;
+	}
+	wq_list_del(&acct->work_list, &work->list, prev);
+}
+
+static bool io_acct_cancel_pending_work(struct io_wqe *wqe,
+					struct io_wqe_acct *acct,
+					struct io_cb_cancel_data *match)
+{
+	struct io_wq_work_node *node, *prev;
+	struct io_wq_work *work;
+
+	raw_spin_lock(&acct->lock);
+	wq_list_for_each(node, prev, &acct->work_list) {
+		work = container_of(node, struct io_wq_work, list);
+		if (!match->fn(work, match->data))
+			continue;
+		io_wqe_remove_pending(wqe, work, prev);
+		raw_spin_unlock(&acct->lock);
+		io_run_cancel(work, wqe);
+		match->nr_pending++;
+		/* not safe to continue after unlock */
+		return true;
+	}
+	raw_spin_unlock(&acct->lock);
+
+	return false;
+}
+
+static void io_wqe_cancel_pending_work(struct io_wqe *wqe,
+				       struct io_cb_cancel_data *match)
+{
+	int i;
+retry:
+	for (i = 0; i < IO_WQ_ACCT_NR; i++) {
+		struct io_wqe_acct *acct = io_get_acct(wqe, i == 0);
+
+		if (io_acct_cancel_pending_work(wqe, acct, match)) {
+			if (match->cancel_all)
+				goto retry;
+			break;
+		}
+	}
+}
+
+static void io_wqe_cancel_running_work(struct io_wqe *wqe,
+				       struct io_cb_cancel_data *match)
+{
+	rcu_read_lock();
+	io_wq_for_each_worker(wqe, io_wq_worker_cancel, match);
+	rcu_read_unlock();
+}
+
+enum io_wq_cancel io_wq_cancel_cb(struct io_wq *wq, work_cancel_fn *cancel,
+				  void *data, bool cancel_all)
+{
+	struct io_cb_cancel_data match = {
+		.fn		= cancel,
+		.data		= data,
+		.cancel_all	= cancel_all,
+	};
+	int node;
+
+	/*
+	 * First check pending list, if we're lucky we can just remove it
+	 * from there. CANCEL_OK means that the work is returned as-new,
+	 * no completion will be posted for it.
+	 *
+	 * Then check if a free (going busy) or busy worker has the work
+	 * currently running. If we find it there, we'll return CANCEL_RUNNING
+	 * as an indication that we attempt to signal cancellation. The
+	 * completion will run normally in this case.
+	 *
+	 * Do both of these while holding the wqe->lock, to ensure that
+	 * we'll find a work item regardless of state.
+	 */
+	for_each_node(node) {
+		struct io_wqe *wqe = wq->wqes[node];
+
+		io_wqe_cancel_pending_work(wqe, &match);
+		if (match.nr_pending && !match.cancel_all)
+			return IO_WQ_CANCEL_OK;
+
+		raw_spin_lock(&wqe->lock);
+		io_wqe_cancel_running_work(wqe, &match);
+		raw_spin_unlock(&wqe->lock);
+		if (match.nr_running && !match.cancel_all)
+			return IO_WQ_CANCEL_RUNNING;
+	}
+
+	if (match.nr_running)
+		return IO_WQ_CANCEL_RUNNING;
+	if (match.nr_pending)
+		return IO_WQ_CANCEL_OK;
+	return IO_WQ_CANCEL_NOTFOUND;
+}
+
+static int io_wqe_hash_wake(struct wait_queue_entry *wait, unsigned mode,
+			    int sync, void *key)
+{
+	struct io_wqe *wqe = container_of(wait, struct io_wqe, wait);
+	int i;
+
+	list_del_init(&wait->entry);
+
+	rcu_read_lock();
+	for (i = 0; i < IO_WQ_ACCT_NR; i++) {
+		struct io_wqe_acct *acct = &wqe->acct[i];
+
+		if (test_and_clear_bit(IO_ACCT_STALLED_BIT, &acct->flags))
+			io_wqe_activate_free_worker(wqe, acct);
+	}
+	rcu_read_unlock();
+	return 1;
+}
+
+struct io_wq *io_wq_create(unsigned bounded, struct io_wq_data *data)
+{
+	int ret, node, i;
+	struct io_wq *wq;
+
+	if (WARN_ON_ONCE(!data->free_work || !data->do_work))
+		return ERR_PTR(-EINVAL);
+	if (WARN_ON_ONCE(!bounded))
+		return ERR_PTR(-EINVAL);
+
+	wq = kzalloc(struct_size(wq, wqes, nr_node_ids), GFP_KERNEL);
+	if (!wq)
+		return ERR_PTR(-ENOMEM);
+	ret = cpuhp_state_add_instance_nocalls(io_wq_online, &wq->cpuhp_node);
+	if (ret)
+		goto err_wq;
+
+	refcount_inc(&data->hash->refs);
+	wq->hash = data->hash;
+	wq->free_work = data->free_work;
+	wq->do_work = data->do_work;
+
+	ret = -ENOMEM;
+	for_each_node(node) {
+		struct io_wqe *wqe;
+		int alloc_node = node;
+
+		if (!node_online(alloc_node))
+			alloc_node = NUMA_NO_NODE;
+		wqe = kzalloc_node(sizeof(struct io_wqe), GFP_KERNEL, alloc_node);
+		if (!wqe)
+			goto err;
+		if (!alloc_cpumask_var(&wqe->cpu_mask, GFP_KERNEL))
+			goto err;
+		cpumask_copy(wqe->cpu_mask, cpumask_of_node(node));
+		wq->wqes[node] = wqe;
+		wqe->node = alloc_node;
+		wqe->acct[IO_WQ_ACCT_BOUND].max_workers = bounded;
+		wqe->acct[IO_WQ_ACCT_UNBOUND].max_workers =
+					task_rlimit(current, RLIMIT_NPROC);
+		INIT_LIST_HEAD(&wqe->wait.entry);
+		wqe->wait.func = io_wqe_hash_wake;
+		for (i = 0; i < IO_WQ_ACCT_NR; i++) {
+			struct io_wqe_acct *acct = &wqe->acct[i];
+
+			acct->index = i;
+			atomic_set(&acct->nr_running, 0);
+			INIT_WQ_LIST(&acct->work_list);
+			raw_spin_lock_init(&acct->lock);
+		}
+		wqe->wq = wq;
+		raw_spin_lock_init(&wqe->lock);
+		INIT_HLIST_NULLS_HEAD(&wqe->free_list, 0);
+		INIT_LIST_HEAD(&wqe->all_list);
+	}
+
+	wq->task = get_task_struct(data->task);
+	atomic_set(&wq->worker_refs, 1);
+	init_completion(&wq->worker_done);
+	return wq;
+err:
+	io_wq_put_hash(data->hash);
+	cpuhp_state_remove_instance_nocalls(io_wq_online, &wq->cpuhp_node);
+	for_each_node(node) {
+		if (!wq->wqes[node])
+			continue;
+		free_cpumask_var(wq->wqes[node]->cpu_mask);
+		kfree(wq->wqes[node]);
+	}
+err_wq:
+	kfree(wq);
+	return ERR_PTR(ret);
+}
+
+static bool io_task_work_match(struct callback_head *cb, void *data)
+{
+	struct io_worker *worker;
+
+	if (cb->func != create_worker_cb && cb->func != create_worker_cont)
+		return false;
+	worker = container_of(cb, struct io_worker, create_work);
+	return worker->wqe->wq == data;
+}
+
+void io_wq_exit_start(struct io_wq *wq)
+{
+	set_bit(IO_WQ_BIT_EXIT, &wq->state);
+}
+
+static void io_wq_cancel_tw_create(struct io_wq *wq)
+{
+	struct callback_head *cb;
+
+	while ((cb = task_work_cancel_match(wq->task, io_task_work_match, wq)) != NULL) {
+		struct io_worker *worker;
+
+		worker = container_of(cb, struct io_worker, create_work);
+		io_worker_cancel_cb(worker);
+	}
+}
+
+static void io_wq_exit_workers(struct io_wq *wq)
+{
+	int node;
+
+	if (!wq->task)
+		return;
+
+	io_wq_cancel_tw_create(wq);
+
+	rcu_read_lock();
+	for_each_node(node) {
+		struct io_wqe *wqe = wq->wqes[node];
+
+		io_wq_for_each_worker(wqe, io_wq_worker_wake, NULL);
+	}
+	rcu_read_unlock();
+	io_worker_ref_put(wq);
+	wait_for_completion(&wq->worker_done);
+
+	for_each_node(node) {
+		spin_lock_irq(&wq->hash->wait.lock);
+		list_del_init(&wq->wqes[node]->wait.entry);
+		spin_unlock_irq(&wq->hash->wait.lock);
+	}
+	put_task_struct(wq->task);
+	wq->task = NULL;
+}
+
+static void io_wq_destroy(struct io_wq *wq)
+{
+	int node;
+
+	cpuhp_state_remove_instance_nocalls(io_wq_online, &wq->cpuhp_node);
+
+	for_each_node(node) {
+		struct io_wqe *wqe = wq->wqes[node];
+		struct io_cb_cancel_data match = {
+			.fn		= io_wq_work_match_all,
+			.cancel_all	= true,
+		};
+		io_wqe_cancel_pending_work(wqe, &match);
+		free_cpumask_var(wqe->cpu_mask);
+		kfree(wqe);
+	}
+	io_wq_put_hash(wq->hash);
+	kfree(wq);
+}
+
+void io_wq_put_and_exit(struct io_wq *wq)
+{
+	WARN_ON_ONCE(!test_bit(IO_WQ_BIT_EXIT, &wq->state));
+
+	io_wq_exit_workers(wq);
+	io_wq_destroy(wq);
+}
+
+struct online_data {
+	unsigned int cpu;
+	bool online;
+};
+
+static bool io_wq_worker_affinity(struct io_worker *worker, void *data)
+{
+	struct online_data *od = data;
+
+	if (od->online)
+		cpumask_set_cpu(od->cpu, worker->wqe->cpu_mask);
+	else
+		cpumask_clear_cpu(od->cpu, worker->wqe->cpu_mask);
+	return false;
+}
+
+static int __io_wq_cpu_online(struct io_wq *wq, unsigned int cpu, bool online)
+{
+	struct online_data od = {
+		.cpu = cpu,
+		.online = online
+	};
+	int i;
+
+	rcu_read_lock();
+	for_each_node(i)
+		io_wq_for_each_worker(wq->wqes[i], io_wq_worker_affinity, &od);
+	rcu_read_unlock();
+	return 0;
+}
+
+static int io_wq_cpu_online(unsigned int cpu, struct hlist_node *node)
+{
+	struct io_wq *wq = hlist_entry_safe(node, struct io_wq, cpuhp_node);
+
+	return __io_wq_cpu_online(wq, cpu, true);
+}
+
+static int io_wq_cpu_offline(unsigned int cpu, struct hlist_node *node)
+{
+	struct io_wq *wq = hlist_entry_safe(node, struct io_wq, cpuhp_node);
+
+	return __io_wq_cpu_online(wq, cpu, false);
+}
+
+int io_wq_cpu_affinity(struct io_wq *wq, cpumask_var_t mask)
+{
+	int i;
+
+	rcu_read_lock();
+	for_each_node(i) {
+		struct io_wqe *wqe = wq->wqes[i];
+
+		if (mask)
+			cpumask_copy(wqe->cpu_mask, mask);
+		else
+			cpumask_copy(wqe->cpu_mask, cpumask_of_node(i));
+	}
+	rcu_read_unlock();
+	return 0;
+}
+
+/*
+ * Set max number of unbounded workers, returns old value. If new_count is 0,
+ * then just return the old value.
+ */
+int io_wq_max_workers(struct io_wq *wq, int *new_count)
+{
+	int prev[IO_WQ_ACCT_NR];
+	bool first_node = true;
+	int i, node;
+
+	BUILD_BUG_ON((int) IO_WQ_ACCT_BOUND   != (int) IO_WQ_BOUND);
+	BUILD_BUG_ON((int) IO_WQ_ACCT_UNBOUND != (int) IO_WQ_UNBOUND);
+	BUILD_BUG_ON((int) IO_WQ_ACCT_NR      != 2);
+
+	for (i = 0; i < IO_WQ_ACCT_NR; i++) {
+		if (new_count[i] > task_rlimit(current, RLIMIT_NPROC))
+			new_count[i] = task_rlimit(current, RLIMIT_NPROC);
+	}
+
+	for (i = 0; i < IO_WQ_ACCT_NR; i++)
+		prev[i] = 0;
+
+	rcu_read_lock();
+	for_each_node(node) {
+		struct io_wqe *wqe = wq->wqes[node];
+		struct io_wqe_acct *acct;
+
+		raw_spin_lock(&wqe->lock);
+		for (i = 0; i < IO_WQ_ACCT_NR; i++) {
+			acct = &wqe->acct[i];
+			if (first_node)
+				prev[i] = max_t(int, acct->max_workers, prev[i]);
+			if (new_count[i])
+				acct->max_workers = new_count[i];
+		}
+		raw_spin_unlock(&wqe->lock);
+		first_node = false;
+	}
+	rcu_read_unlock();
+
+	for (i = 0; i < IO_WQ_ACCT_NR; i++)
+		new_count[i] = prev[i];
+
+	return 0;
+}
+
+static __init int io_wq_init(void)
+{
+	int ret;
+
+	ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN, "io-wq/online",
+					io_wq_cpu_online, io_wq_cpu_offline);
+	if (ret < 0)
+		return ret;
+	io_wq_online = ret;
+	return 0;
+}
+subsys_initcall(io_wq_init);
diff --git a/io_uring/io-wq.h b/io_uring/io-wq.h
new file mode 100644
index 000000000000..ba6eee76d028
--- /dev/null
+++ b/io_uring/io-wq.h
@@ -0,0 +1,228 @@
+#ifndef INTERNAL_IO_WQ_H
+#define INTERNAL_IO_WQ_H
+
+#include <linux/refcount.h>
+
+struct io_wq;
+
+enum {
+	IO_WQ_WORK_CANCEL	= 1,
+	IO_WQ_WORK_HASHED	= 2,
+	IO_WQ_WORK_UNBOUND	= 4,
+	IO_WQ_WORK_CONCURRENT	= 16,
+
+	IO_WQ_HASH_SHIFT	= 24,	/* upper 8 bits are used for hash key */
+};
+
+enum io_wq_cancel {
+	IO_WQ_CANCEL_OK,	/* cancelled before started */
+	IO_WQ_CANCEL_RUNNING,	/* found, running, and attempted cancelled */
+	IO_WQ_CANCEL_NOTFOUND,	/* work not found */
+};
+
+struct io_wq_work_node {
+	struct io_wq_work_node *next;
+};
+
+struct io_wq_work_list {
+	struct io_wq_work_node *first;
+	struct io_wq_work_node *last;
+};
+
+#define wq_list_for_each(pos, prv, head)			\
+	for (pos = (head)->first, prv = NULL; pos; prv = pos, pos = (pos)->next)
+
+#define wq_list_for_each_resume(pos, prv)			\
+	for (; pos; prv = pos, pos = (pos)->next)
+
+#define wq_list_empty(list)	(READ_ONCE((list)->first) == NULL)
+#define INIT_WQ_LIST(list)	do {				\
+	(list)->first = NULL;					\
+} while (0)
+
+static inline void wq_list_add_after(struct io_wq_work_node *node,
+				     struct io_wq_work_node *pos,
+				     struct io_wq_work_list *list)
+{
+	struct io_wq_work_node *next = pos->next;
+
+	pos->next = node;
+	node->next = next;
+	if (!next)
+		list->last = node;
+}
+
+/**
+ * wq_list_merge - merge the second list to the first one.
+ * @list0: the first list
+ * @list1: the second list
+ * Return the first node after mergence.
+ */
+static inline struct io_wq_work_node *wq_list_merge(struct io_wq_work_list *list0,
+						    struct io_wq_work_list *list1)
+{
+	struct io_wq_work_node *ret;
+
+	if (!list0->first) {
+		ret = list1->first;
+	} else {
+		ret = list0->first;
+		list0->last->next = list1->first;
+	}
+	INIT_WQ_LIST(list0);
+	INIT_WQ_LIST(list1);
+	return ret;
+}
+
+static inline void wq_list_add_tail(struct io_wq_work_node *node,
+				    struct io_wq_work_list *list)
+{
+	node->next = NULL;
+	if (!list->first) {
+		list->last = node;
+		WRITE_ONCE(list->first, node);
+	} else {
+		list->last->next = node;
+		list->last = node;
+	}
+}
+
+static inline void wq_list_add_head(struct io_wq_work_node *node,
+				    struct io_wq_work_list *list)
+{
+	node->next = list->first;
+	if (!node->next)
+		list->last = node;
+	WRITE_ONCE(list->first, node);
+}
+
+static inline void wq_list_cut(struct io_wq_work_list *list,
+			       struct io_wq_work_node *last,
+			       struct io_wq_work_node *prev)
+{
+	/* first in the list, if prev==NULL */
+	if (!prev)
+		WRITE_ONCE(list->first, last->next);
+	else
+		prev->next = last->next;
+
+	if (last == list->last)
+		list->last = prev;
+	last->next = NULL;
+}
+
+static inline void __wq_list_splice(struct io_wq_work_list *list,
+				    struct io_wq_work_node *to)
+{
+	list->last->next = to->next;
+	to->next = list->first;
+	INIT_WQ_LIST(list);
+}
+
+static inline bool wq_list_splice(struct io_wq_work_list *list,
+				  struct io_wq_work_node *to)
+{
+	if (!wq_list_empty(list)) {
+		__wq_list_splice(list, to);
+		return true;
+	}
+	return false;
+}
+
+static inline void wq_stack_add_head(struct io_wq_work_node *node,
+				     struct io_wq_work_node *stack)
+{
+	node->next = stack->next;
+	stack->next = node;
+}
+
+static inline void wq_list_del(struct io_wq_work_list *list,
+			       struct io_wq_work_node *node,
+			       struct io_wq_work_node *prev)
+{
+	wq_list_cut(list, node, prev);
+}
+
+static inline
+struct io_wq_work_node *wq_stack_extract(struct io_wq_work_node *stack)
+{
+	struct io_wq_work_node *node = stack->next;
+
+	stack->next = node->next;
+	return node;
+}
+
+struct io_wq_work {
+	struct io_wq_work_node list;
+	unsigned flags;
+	int cancel_seq;
+};
+
+static inline struct io_wq_work *wq_next_work(struct io_wq_work *work)
+{
+	if (!work->list.next)
+		return NULL;
+
+	return container_of(work->list.next, struct io_wq_work, list);
+}
+
+typedef struct io_wq_work *(free_work_fn)(struct io_wq_work *);
+typedef void (io_wq_work_fn)(struct io_wq_work *);
+
+struct io_wq_hash {
+	refcount_t refs;
+	unsigned long map;
+	struct wait_queue_head wait;
+};
+
+static inline void io_wq_put_hash(struct io_wq_hash *hash)
+{
+	if (refcount_dec_and_test(&hash->refs))
+		kfree(hash);
+}
+
+struct io_wq_data {
+	struct io_wq_hash *hash;
+	struct task_struct *task;
+	io_wq_work_fn *do_work;
+	free_work_fn *free_work;
+};
+
+struct io_wq *io_wq_create(unsigned bounded, struct io_wq_data *data);
+void io_wq_exit_start(struct io_wq *wq);
+void io_wq_put_and_exit(struct io_wq *wq);
+
+void io_wq_enqueue(struct io_wq *wq, struct io_wq_work *work);
+void io_wq_hash_work(struct io_wq_work *work, void *val);
+
+int io_wq_cpu_affinity(struct io_wq *wq, cpumask_var_t mask);
+int io_wq_max_workers(struct io_wq *wq, int *new_count);
+
+static inline bool io_wq_is_hashed(struct io_wq_work *work)
+{
+	return work->flags & IO_WQ_WORK_HASHED;
+}
+
+typedef bool (work_cancel_fn)(struct io_wq_work *, void *);
+
+enum io_wq_cancel io_wq_cancel_cb(struct io_wq *wq, work_cancel_fn *cancel,
+					void *data, bool cancel_all);
+
+#if defined(CONFIG_IO_WQ)
+extern void io_wq_worker_sleeping(struct task_struct *);
+extern void io_wq_worker_running(struct task_struct *);
+#else
+static inline void io_wq_worker_sleeping(struct task_struct *tsk)
+{
+}
+static inline void io_wq_worker_running(struct task_struct *tsk)
+{
+}
+#endif
+
+static inline bool io_wq_current_is_worker(void)
+{
+	return in_task() && (current->flags & PF_IO_WORKER) &&
+		current->worker_private;
+}
+#endif
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
new file mode 100644
index 000000000000..f429b68d1fc2
--- /dev/null
+++ b/io_uring/io_uring.c
@@ -0,0 +1,13165 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Shared application/kernel submission and completion ring pairs, for
+ * supporting fast/efficient IO.
+ *
+ * A note on the read/write ordering memory barriers that are matched between
+ * the application and kernel side.
+ *
+ * After the application reads the CQ ring tail, it must use an
+ * appropriate smp_rmb() to pair with the smp_wmb() the kernel uses
+ * before writing the tail (using smp_load_acquire to read the tail will
+ * do). It also needs a smp_mb() before updating CQ head (ordering the
+ * entry load(s) with the head store), pairing with an implicit barrier
+ * through a control-dependency in io_get_cqe (smp_store_release to
+ * store head will do). Failure to do so could lead to reading invalid
+ * CQ entries.
+ *
+ * Likewise, the application must use an appropriate smp_wmb() before
+ * writing the SQ tail (ordering SQ entry stores with the tail store),
+ * which pairs with smp_load_acquire in io_get_sqring (smp_store_release
+ * to store the tail will do). And it needs a barrier ordering the SQ
+ * head load before writing new SQ entries (smp_load_acquire to read
+ * head will do).
+ *
+ * When using the SQ poll thread (IORING_SETUP_SQPOLL), the application
+ * needs to check the SQ flags for IORING_SQ_NEED_WAKEUP *after*
+ * updating the SQ tail; a full memory barrier smp_mb() is needed
+ * between.
+ *
+ * Also see the examples in the liburing library:
+ *
+ *	git://git.kernel.dk/liburing
+ *
+ * io_uring also uses READ/WRITE_ONCE() for _any_ store or load that happens
+ * from data shared between the kernel and application. This is done both
+ * for ordering purposes, but also to ensure that once a value is loaded from
+ * data that the application could potentially modify, it remains stable.
+ *
+ * Copyright (C) 2018-2019 Jens Axboe
+ * Copyright (c) 2018-2019 Christoph Hellwig
+ */
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/errno.h>
+#include <linux/syscalls.h>
+#include <linux/compat.h>
+#include <net/compat.h>
+#include <linux/refcount.h>
+#include <linux/uio.h>
+#include <linux/bits.h>
+
+#include <linux/sched/signal.h>
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/fdtable.h>
+#include <linux/mm.h>
+#include <linux/mman.h>
+#include <linux/percpu.h>
+#include <linux/slab.h>
+#include <linux/blk-mq.h>
+#include <linux/bvec.h>
+#include <linux/net.h>
+#include <net/sock.h>
+#include <net/af_unix.h>
+#include <net/scm.h>
+#include <linux/anon_inodes.h>
+#include <linux/sched/mm.h>
+#include <linux/uaccess.h>
+#include <linux/nospec.h>
+#include <linux/sizes.h>
+#include <linux/hugetlb.h>
+#include <linux/highmem.h>
+#include <linux/namei.h>
+#include <linux/fsnotify.h>
+#include <linux/fadvise.h>
+#include <linux/eventpoll.h>
+#include <linux/splice.h>
+#include <linux/task_work.h>
+#include <linux/pagemap.h>
+#include <linux/io_uring.h>
+#include <linux/audit.h>
+#include <linux/security.h>
+#include <linux/xattr.h>
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/io_uring.h>
+
+#include <uapi/linux/io_uring.h>
+
+#include "../fs/internal.h"
+#include "io-wq.h"
+
+#define IORING_MAX_ENTRIES	32768
+#define IORING_MAX_CQ_ENTRIES	(2 * IORING_MAX_ENTRIES)
+#define IORING_SQPOLL_CAP_ENTRIES_VALUE 8
+
+/* only define max */
+#define IORING_MAX_FIXED_FILES	(1U << 20)
+#define IORING_MAX_RESTRICTIONS	(IORING_RESTRICTION_LAST + \
+				 IORING_REGISTER_LAST + IORING_OP_LAST)
+
+#define IO_RSRC_TAG_TABLE_SHIFT	(PAGE_SHIFT - 3)
+#define IO_RSRC_TAG_TABLE_MAX	(1U << IO_RSRC_TAG_TABLE_SHIFT)
+#define IO_RSRC_TAG_TABLE_MASK	(IO_RSRC_TAG_TABLE_MAX - 1)
+
+#define IORING_MAX_REG_BUFFERS	(1U << 14)
+
+#define SQE_COMMON_FLAGS (IOSQE_FIXED_FILE | IOSQE_IO_LINK | \
+			  IOSQE_IO_HARDLINK | IOSQE_ASYNC)
+
+#define SQE_VALID_FLAGS	(SQE_COMMON_FLAGS | IOSQE_BUFFER_SELECT | \
+			IOSQE_IO_DRAIN | IOSQE_CQE_SKIP_SUCCESS)
+
+#define IO_REQ_CLEAN_FLAGS (REQ_F_BUFFER_SELECTED | REQ_F_NEED_CLEANUP | \
+				REQ_F_POLLED | REQ_F_INFLIGHT | REQ_F_CREDS | \
+				REQ_F_ASYNC_DATA)
+
+#define IO_REQ_CLEAN_SLOW_FLAGS (REQ_F_REFCOUNT | REQ_F_LINK | REQ_F_HARDLINK |\
+				 IO_REQ_CLEAN_FLAGS)
+
+#define IO_APOLL_MULTI_POLLED (REQ_F_APOLL_MULTISHOT | REQ_F_POLLED)
+
+#define IO_TCTX_REFS_CACHE_NR	(1U << 10)
+
+struct io_uring {
+	u32 head ____cacheline_aligned_in_smp;
+	u32 tail ____cacheline_aligned_in_smp;
+};
+
+/*
+ * This data is shared with the application through the mmap at offsets
+ * IORING_OFF_SQ_RING and IORING_OFF_CQ_RING.
+ *
+ * The offsets to the member fields are published through struct
+ * io_sqring_offsets when calling io_uring_setup.
+ */
+struct io_rings {
+	/*
+	 * Head and tail offsets into the ring; the offsets need to be
+	 * masked to get valid indices.
+	 *
+	 * The kernel controls head of the sq ring and the tail of the cq ring,
+	 * and the application controls tail of the sq ring and the head of the
+	 * cq ring.
+	 */
+	struct io_uring		sq, cq;
+	/*
+	 * Bitmasks to apply to head and tail offsets (constant, equals
+	 * ring_entries - 1)
+	 */
+	u32			sq_ring_mask, cq_ring_mask;
+	/* Ring sizes (constant, power of 2) */
+	u32			sq_ring_entries, cq_ring_entries;
+	/*
+	 * Number of invalid entries dropped by the kernel due to
+	 * invalid index stored in array
+	 *
+	 * Written by the kernel, shouldn't be modified by the
+	 * application (i.e. get number of "new events" by comparing to
+	 * cached value).
+	 *
+	 * After a new SQ head value was read by the application this
+	 * counter includes all submissions that were dropped reaching
+	 * the new SQ head (and possibly more).
+	 */
+	u32			sq_dropped;
+	/*
+	 * Runtime SQ flags
+	 *
+	 * Written by the kernel, shouldn't be modified by the
+	 * application.
+	 *
+	 * The application needs a full memory barrier before checking
+	 * for IORING_SQ_NEED_WAKEUP after updating the sq tail.
+	 */
+	atomic_t		sq_flags;
+	/*
+	 * Runtime CQ flags
+	 *
+	 * Written by the application, shouldn't be modified by the
+	 * kernel.
+	 */
+	u32			cq_flags;
+	/*
+	 * Number of completion events lost because the queue was full;
+	 * this should be avoided by the application by making sure
+	 * there are not more requests pending than there is space in
+	 * the completion queue.
+	 *
+	 * Written by the kernel, shouldn't be modified by the
+	 * application (i.e. get number of "new events" by comparing to
+	 * cached value).
+	 *
+	 * As completion events come in out of order this counter is not
+	 * ordered with any other data.
+	 */
+	u32			cq_overflow;
+	/*
+	 * Ring buffer of completion events.
+	 *
+	 * The kernel writes completion events fresh every time they are
+	 * produced, so the application is allowed to modify pending
+	 * entries.
+	 */
+	struct io_uring_cqe	cqes[] ____cacheline_aligned_in_smp;
+};
+
+struct io_mapped_ubuf {
+	u64		ubuf;
+	u64		ubuf_end;
+	unsigned int	nr_bvecs;
+	unsigned long	acct_pages;
+	struct bio_vec	bvec[];
+};
+
+struct io_ring_ctx;
+
+struct io_overflow_cqe {
+	struct list_head list;
+	struct io_uring_cqe cqe;
+};
+
+/*
+ * FFS_SCM is only available on 64-bit archs, for 32-bit we just define it as 0
+ * and define IO_URING_SCM_ALL. For this case, we use SCM for all files as we
+ * can't safely always dereference the file when the task has exited and ring
+ * cleanup is done. If a file is tracked and part of SCM, then unix gc on
+ * process exit may reap it before __io_sqe_files_unregister() is run.
+ */
+#define FFS_NOWAIT		0x1UL
+#define FFS_ISREG		0x2UL
+#if defined(CONFIG_64BIT)
+#define FFS_SCM			0x4UL
+#else
+#define IO_URING_SCM_ALL
+#define FFS_SCM			0x0UL
+#endif
+#define FFS_MASK		~(FFS_NOWAIT|FFS_ISREG|FFS_SCM)
+
+struct io_fixed_file {
+	/* file * with additional FFS_* flags */
+	unsigned long file_ptr;
+};
+
+struct io_rsrc_put {
+	struct list_head list;
+	u64 tag;
+	union {
+		void *rsrc;
+		struct file *file;
+		struct io_mapped_ubuf *buf;
+	};
+};
+
+struct io_file_table {
+	struct io_fixed_file *files;
+	unsigned long *bitmap;
+	unsigned int alloc_hint;
+};
+
+struct io_rsrc_node {
+	struct percpu_ref		refs;
+	struct list_head		node;
+	struct list_head		rsrc_list;
+	struct io_rsrc_data		*rsrc_data;
+	struct llist_node		llist;
+	bool				done;
+};
+
+typedef void (rsrc_put_fn)(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc);
+
+struct io_rsrc_data {
+	struct io_ring_ctx		*ctx;
+
+	u64				**tags;
+	unsigned int			nr;
+	rsrc_put_fn			*do_put;
+	atomic_t			refs;
+	struct completion		done;
+	bool				quiesce;
+};
+
+#define IO_BUFFER_LIST_BUF_PER_PAGE (PAGE_SIZE / sizeof(struct io_uring_buf))
+struct io_buffer_list {
+	/*
+	 * If ->buf_nr_pages is set, then buf_pages/buf_ring are used. If not,
+	 * then these are classic provided buffers and ->buf_list is used.
+	 */
+	union {
+		struct list_head buf_list;
+		struct {
+			struct page **buf_pages;
+			struct io_uring_buf_ring *buf_ring;
+		};
+	};
+	__u16 bgid;
+
+	/* below is for ring provided buffers */
+	__u16 buf_nr_pages;
+	__u16 nr_entries;
+	__u16 head;
+	__u16 mask;
+};
+
+struct io_buffer {
+	struct list_head list;
+	__u64 addr;
+	__u32 len;
+	__u16 bid;
+	__u16 bgid;
+};
+
+struct io_restriction {
+	DECLARE_BITMAP(register_op, IORING_REGISTER_LAST);
+	DECLARE_BITMAP(sqe_op, IORING_OP_LAST);
+	u8 sqe_flags_allowed;
+	u8 sqe_flags_required;
+	bool registered;
+};
+
+enum {
+	IO_SQ_THREAD_SHOULD_STOP = 0,
+	IO_SQ_THREAD_SHOULD_PARK,
+};
+
+struct io_sq_data {
+	refcount_t		refs;
+	atomic_t		park_pending;
+	struct mutex		lock;
+
+	/* ctx's that are using this sqd */
+	struct list_head	ctx_list;
+
+	struct task_struct	*thread;
+	struct wait_queue_head	wait;
+
+	unsigned		sq_thread_idle;
+	int			sq_cpu;
+	pid_t			task_pid;
+	pid_t			task_tgid;
+
+	unsigned long		state;
+	struct completion	exited;
+};
+
+#define IO_COMPL_BATCH			32
+#define IO_REQ_CACHE_SIZE		32
+#define IO_REQ_ALLOC_BATCH		8
+
+struct io_submit_link {
+	struct io_kiocb		*head;
+	struct io_kiocb		*last;
+};
+
+struct io_submit_state {
+	/* inline/task_work completion list, under ->uring_lock */
+	struct io_wq_work_node	free_list;
+	/* batch completion logic */
+	struct io_wq_work_list	compl_reqs;
+	struct io_submit_link	link;
+
+	bool			plug_started;
+	bool			need_plug;
+	bool			flush_cqes;
+	unsigned short		submit_nr;
+	struct blk_plug		plug;
+};
+
+struct io_ev_fd {
+	struct eventfd_ctx	*cq_ev_fd;
+	unsigned int		eventfd_async: 1;
+	struct rcu_head		rcu;
+};
+
+#define BGID_ARRAY	64
+
+struct io_ring_ctx {
+	/* const or read-mostly hot data */
+	struct {
+		struct percpu_ref	refs;
+
+		struct io_rings		*rings;
+		unsigned int		flags;
+		enum task_work_notify_mode	notify_method;
+		unsigned int		compat: 1;
+		unsigned int		drain_next: 1;
+		unsigned int		restricted: 1;
+		unsigned int		off_timeout_used: 1;
+		unsigned int		drain_active: 1;
+		unsigned int		drain_disabled: 1;
+		unsigned int		has_evfd: 1;
+		unsigned int		syscall_iopoll: 1;
+	} ____cacheline_aligned_in_smp;
+
+	/* submission data */
+	struct {
+		struct mutex		uring_lock;
+
+		/*
+		 * Ring buffer of indices into array of io_uring_sqe, which is
+		 * mmapped by the application using the IORING_OFF_SQES offset.
+		 *
+		 * This indirection could e.g. be used to assign fixed
+		 * io_uring_sqe entries to operations and only submit them to
+		 * the queue when needed.
+		 *
+		 * The kernel modifies neither the indices array nor the entries
+		 * array.
+		 */
+		u32			*sq_array;
+		struct io_uring_sqe	*sq_sqes;
+		unsigned		cached_sq_head;
+		unsigned		sq_entries;
+		struct list_head	defer_list;
+
+		/*
+		 * Fixed resources fast path, should be accessed only under
+		 * uring_lock, and updated through io_uring_register(2)
+		 */
+		struct io_rsrc_node	*rsrc_node;
+		int			rsrc_cached_refs;
+		atomic_t		cancel_seq;
+		struct io_file_table	file_table;
+		unsigned		nr_user_files;
+		unsigned		nr_user_bufs;
+		struct io_mapped_ubuf	**user_bufs;
+
+		struct io_submit_state	submit_state;
+
+		struct io_buffer_list	*io_bl;
+		struct xarray		io_bl_xa;
+		struct list_head	io_buffers_cache;
+
+		struct list_head	timeout_list;
+		struct list_head	ltimeout_list;
+		struct list_head	cq_overflow_list;
+		struct list_head	apoll_cache;
+		struct xarray		personalities;
+		u32			pers_next;
+		unsigned		sq_thread_idle;
+	} ____cacheline_aligned_in_smp;
+
+	/* IRQ completion list, under ->completion_lock */
+	struct io_wq_work_list	locked_free_list;
+	unsigned int		locked_free_nr;
+
+	const struct cred	*sq_creds;	/* cred used for __io_sq_thread() */
+	struct io_sq_data	*sq_data;	/* if using sq thread polling */
+
+	struct wait_queue_head	sqo_sq_wait;
+	struct list_head	sqd_list;
+
+	unsigned long		check_cq;
+
+	struct {
+		/*
+		 * We cache a range of free CQEs we can use, once exhausted it
+		 * should go through a slower range setup, see __io_get_cqe()
+		 */
+		struct io_uring_cqe	*cqe_cached;
+		struct io_uring_cqe	*cqe_sentinel;
+
+		unsigned		cached_cq_tail;
+		unsigned		cq_entries;
+		struct io_ev_fd	__rcu	*io_ev_fd;
+		struct wait_queue_head	cq_wait;
+		unsigned		cq_extra;
+		atomic_t		cq_timeouts;
+		unsigned		cq_last_tm_flush;
+	} ____cacheline_aligned_in_smp;
+
+	struct {
+		spinlock_t		completion_lock;
+
+		spinlock_t		timeout_lock;
+
+		/*
+		 * ->iopoll_list is protected by the ctx->uring_lock for
+		 * io_uring instances that don't use IORING_SETUP_SQPOLL.
+		 * For SQPOLL, only the single threaded io_sq_thread() will
+		 * manipulate the list, hence no extra locking is needed there.
+		 */
+		struct io_wq_work_list	iopoll_list;
+		struct hlist_head	*cancel_hash;
+		unsigned		cancel_hash_bits;
+		bool			poll_multi_queue;
+
+		struct list_head	io_buffers_comp;
+	} ____cacheline_aligned_in_smp;
+
+	struct io_restriction		restrictions;
+
+	/* slow path rsrc auxilary data, used by update/register */
+	struct {
+		struct io_rsrc_node		*rsrc_backup_node;
+		struct io_mapped_ubuf		*dummy_ubuf;
+		struct io_rsrc_data		*file_data;
+		struct io_rsrc_data		*buf_data;
+
+		struct delayed_work		rsrc_put_work;
+		struct llist_head		rsrc_put_llist;
+		struct list_head		rsrc_ref_list;
+		spinlock_t			rsrc_ref_lock;
+
+		struct list_head	io_buffers_pages;
+	};
+
+	/* Keep this last, we don't need it for the fast path */
+	struct {
+		#if defined(CONFIG_UNIX)
+			struct socket		*ring_sock;
+		#endif
+		/* hashed buffered write serialization */
+		struct io_wq_hash		*hash_map;
+
+		/* Only used for accounting purposes */
+		struct user_struct		*user;
+		struct mm_struct		*mm_account;
+
+		/* ctx exit and cancelation */
+		struct llist_head		fallback_llist;
+		struct delayed_work		fallback_work;
+		struct work_struct		exit_work;
+		struct list_head		tctx_list;
+		struct completion		ref_comp;
+		u32				iowq_limits[2];
+		bool				iowq_limits_set;
+	};
+};
+
+/*
+ * Arbitrary limit, can be raised if need be
+ */
+#define IO_RINGFD_REG_MAX 16
+
+struct io_uring_task {
+	/* submission side */
+	int			cached_refs;
+	struct xarray		xa;
+	struct wait_queue_head	wait;
+	const struct io_ring_ctx *last;
+	struct io_wq		*io_wq;
+	struct percpu_counter	inflight;
+	atomic_t		inflight_tracked;
+	atomic_t		in_idle;
+
+	spinlock_t		task_lock;
+	struct io_wq_work_list	task_list;
+	struct io_wq_work_list	prio_task_list;
+	struct callback_head	task_work;
+	struct file		**registered_rings;
+	bool			task_running;
+};
+
+/*
+ * First field must be the file pointer in all the
+ * iocb unions! See also 'struct kiocb' in <linux/fs.h>
+ */
+struct io_poll_iocb {
+	struct file			*file;
+	struct wait_queue_head		*head;
+	__poll_t			events;
+	struct wait_queue_entry		wait;
+};
+
+struct io_poll_update {
+	struct file			*file;
+	u64				old_user_data;
+	u64				new_user_data;
+	__poll_t			events;
+	bool				update_events;
+	bool				update_user_data;
+};
+
+struct io_close {
+	struct file			*file;
+	int				fd;
+	u32				file_slot;
+};
+
+struct io_timeout_data {
+	struct io_kiocb			*req;
+	struct hrtimer			timer;
+	struct timespec64		ts;
+	enum hrtimer_mode		mode;
+	u32				flags;
+};
+
+struct io_accept {
+	struct file			*file;
+	struct sockaddr __user		*addr;
+	int __user			*addr_len;
+	int				flags;
+	u32				file_slot;
+	unsigned long			nofile;
+};
+
+struct io_socket {
+	struct file			*file;
+	int				domain;
+	int				type;
+	int				protocol;
+	int				flags;
+	u32				file_slot;
+	unsigned long			nofile;
+};
+
+struct io_sync {
+	struct file			*file;
+	loff_t				len;
+	loff_t				off;
+	int				flags;
+	int				mode;
+};
+
+struct io_cancel {
+	struct file			*file;
+	u64				addr;
+	u32				flags;
+	s32				fd;
+};
+
+struct io_timeout {
+	struct file			*file;
+	u32				off;
+	u32				target_seq;
+	struct list_head		list;
+	/* head of the link, used by linked timeouts only */
+	struct io_kiocb			*head;
+	/* for linked completions */
+	struct io_kiocb			*prev;
+};
+
+struct io_timeout_rem {
+	struct file			*file;
+	u64				addr;
+
+	/* timeout update */
+	struct timespec64		ts;
+	u32				flags;
+	bool				ltimeout;
+};
+
+struct io_rw {
+	/* NOTE: kiocb has the file as the first member, so don't do it here */
+	struct kiocb			kiocb;
+	u64				addr;
+	u32				len;
+	rwf_t				flags;
+};
+
+struct io_connect {
+	struct file			*file;
+	struct sockaddr __user		*addr;
+	int				addr_len;
+};
+
+struct io_sr_msg {
+	struct file			*file;
+	union {
+		struct compat_msghdr __user	*umsg_compat;
+		struct user_msghdr __user	*umsg;
+		void __user			*buf;
+	};
+	int				msg_flags;
+	size_t				len;
+	size_t				done_io;
+	unsigned int			flags;
+};
+
+struct io_open {
+	struct file			*file;
+	int				dfd;
+	u32				file_slot;
+	struct filename			*filename;
+	struct open_how			how;
+	unsigned long			nofile;
+};
+
+struct io_rsrc_update {
+	struct file			*file;
+	u64				arg;
+	u32				nr_args;
+	u32				offset;
+};
+
+struct io_fadvise {
+	struct file			*file;
+	u64				offset;
+	u32				len;
+	u32				advice;
+};
+
+struct io_madvise {
+	struct file			*file;
+	u64				addr;
+	u32				len;
+	u32				advice;
+};
+
+struct io_epoll {
+	struct file			*file;
+	int				epfd;
+	int				op;
+	int				fd;
+	struct epoll_event		event;
+};
+
+struct io_splice {
+	struct file			*file_out;
+	loff_t				off_out;
+	loff_t				off_in;
+	u64				len;
+	int				splice_fd_in;
+	unsigned int			flags;
+};
+
+struct io_provide_buf {
+	struct file			*file;
+	__u64				addr;
+	__u32				len;
+	__u32				bgid;
+	__u16				nbufs;
+	__u16				bid;
+};
+
+struct io_statx {
+	struct file			*file;
+	int				dfd;
+	unsigned int			mask;
+	unsigned int			flags;
+	struct filename			*filename;
+	struct statx __user		*buffer;
+};
+
+struct io_shutdown {
+	struct file			*file;
+	int				how;
+};
+
+struct io_rename {
+	struct file			*file;
+	int				old_dfd;
+	int				new_dfd;
+	struct filename			*oldpath;
+	struct filename			*newpath;
+	int				flags;
+};
+
+struct io_unlink {
+	struct file			*file;
+	int				dfd;
+	int				flags;
+	struct filename			*filename;
+};
+
+struct io_mkdir {
+	struct file			*file;
+	int				dfd;
+	umode_t				mode;
+	struct filename			*filename;
+};
+
+struct io_symlink {
+	struct file			*file;
+	int				new_dfd;
+	struct filename			*oldpath;
+	struct filename			*newpath;
+};
+
+struct io_hardlink {
+	struct file			*file;
+	int				old_dfd;
+	int				new_dfd;
+	struct filename			*oldpath;
+	struct filename			*newpath;
+	int				flags;
+};
+
+struct io_msg {
+	struct file			*file;
+	u64 user_data;
+	u32 len;
+};
+
+struct io_async_connect {
+	struct sockaddr_storage		address;
+};
+
+struct io_async_msghdr {
+	struct iovec			fast_iov[UIO_FASTIOV];
+	/* points to an allocated iov, if NULL we use fast_iov instead */
+	struct iovec			*free_iov;
+	struct sockaddr __user		*uaddr;
+	struct msghdr			msg;
+	struct sockaddr_storage		addr;
+};
+
+struct io_rw_state {
+	struct iov_iter			iter;
+	struct iov_iter_state		iter_state;
+	struct iovec			fast_iov[UIO_FASTIOV];
+};
+
+struct io_async_rw {
+	struct io_rw_state		s;
+	const struct iovec		*free_iovec;
+	size_t				bytes_done;
+	struct wait_page_queue		wpq;
+};
+
+struct io_xattr {
+	struct file			*file;
+	struct xattr_ctx		ctx;
+	struct filename			*filename;
+};
+
+enum {
+	REQ_F_FIXED_FILE_BIT	= IOSQE_FIXED_FILE_BIT,
+	REQ_F_IO_DRAIN_BIT	= IOSQE_IO_DRAIN_BIT,
+	REQ_F_LINK_BIT		= IOSQE_IO_LINK_BIT,
+	REQ_F_HARDLINK_BIT	= IOSQE_IO_HARDLINK_BIT,
+	REQ_F_FORCE_ASYNC_BIT	= IOSQE_ASYNC_BIT,
+	REQ_F_BUFFER_SELECT_BIT	= IOSQE_BUFFER_SELECT_BIT,
+	REQ_F_CQE_SKIP_BIT	= IOSQE_CQE_SKIP_SUCCESS_BIT,
+
+	/* first byte is taken by user flags, shift it to not overlap */
+	REQ_F_FAIL_BIT		= 8,
+	REQ_F_INFLIGHT_BIT,
+	REQ_F_CUR_POS_BIT,
+	REQ_F_NOWAIT_BIT,
+	REQ_F_LINK_TIMEOUT_BIT,
+	REQ_F_NEED_CLEANUP_BIT,
+	REQ_F_POLLED_BIT,
+	REQ_F_BUFFER_SELECTED_BIT,
+	REQ_F_BUFFER_RING_BIT,
+	REQ_F_COMPLETE_INLINE_BIT,
+	REQ_F_REISSUE_BIT,
+	REQ_F_CREDS_BIT,
+	REQ_F_REFCOUNT_BIT,
+	REQ_F_ARM_LTIMEOUT_BIT,
+	REQ_F_ASYNC_DATA_BIT,
+	REQ_F_SKIP_LINK_CQES_BIT,
+	REQ_F_SINGLE_POLL_BIT,
+	REQ_F_DOUBLE_POLL_BIT,
+	REQ_F_PARTIAL_IO_BIT,
+	REQ_F_CQE32_INIT_BIT,
+	REQ_F_APOLL_MULTISHOT_BIT,
+	/* keep async read/write and isreg together and in order */
+	REQ_F_SUPPORT_NOWAIT_BIT,
+	REQ_F_ISREG_BIT,
+
+	/* not a real bit, just to check we're not overflowing the space */
+	__REQ_F_LAST_BIT,
+};
+
+enum {
+	/* ctx owns file */
+	REQ_F_FIXED_FILE	= BIT(REQ_F_FIXED_FILE_BIT),
+	/* drain existing IO first */
+	REQ_F_IO_DRAIN		= BIT(REQ_F_IO_DRAIN_BIT),
+	/* linked sqes */
+	REQ_F_LINK		= BIT(REQ_F_LINK_BIT),
+	/* doesn't sever on completion < 0 */
+	REQ_F_HARDLINK		= BIT(REQ_F_HARDLINK_BIT),
+	/* IOSQE_ASYNC */
+	REQ_F_FORCE_ASYNC	= BIT(REQ_F_FORCE_ASYNC_BIT),
+	/* IOSQE_BUFFER_SELECT */
+	REQ_F_BUFFER_SELECT	= BIT(REQ_F_BUFFER_SELECT_BIT),
+	/* IOSQE_CQE_SKIP_SUCCESS */
+	REQ_F_CQE_SKIP		= BIT(REQ_F_CQE_SKIP_BIT),
+
+	/* fail rest of links */
+	REQ_F_FAIL		= BIT(REQ_F_FAIL_BIT),
+	/* on inflight list, should be cancelled and waited on exit reliably */
+	REQ_F_INFLIGHT		= BIT(REQ_F_INFLIGHT_BIT),
+	/* read/write uses file position */
+	REQ_F_CUR_POS		= BIT(REQ_F_CUR_POS_BIT),
+	/* must not punt to workers */
+	REQ_F_NOWAIT		= BIT(REQ_F_NOWAIT_BIT),
+	/* has or had linked timeout */
+	REQ_F_LINK_TIMEOUT	= BIT(REQ_F_LINK_TIMEOUT_BIT),
+	/* needs cleanup */
+	REQ_F_NEED_CLEANUP	= BIT(REQ_F_NEED_CLEANUP_BIT),
+	/* already went through poll handler */
+	REQ_F_POLLED		= BIT(REQ_F_POLLED_BIT),
+	/* buffer already selected */
+	REQ_F_BUFFER_SELECTED	= BIT(REQ_F_BUFFER_SELECTED_BIT),
+	/* buffer selected from ring, needs commit */
+	REQ_F_BUFFER_RING	= BIT(REQ_F_BUFFER_RING_BIT),
+	/* completion is deferred through io_comp_state */
+	REQ_F_COMPLETE_INLINE	= BIT(REQ_F_COMPLETE_INLINE_BIT),
+	/* caller should reissue async */
+	REQ_F_REISSUE		= BIT(REQ_F_REISSUE_BIT),
+	/* supports async reads/writes */
+	REQ_F_SUPPORT_NOWAIT	= BIT(REQ_F_SUPPORT_NOWAIT_BIT),
+	/* regular file */
+	REQ_F_ISREG		= BIT(REQ_F_ISREG_BIT),
+	/* has creds assigned */
+	REQ_F_CREDS		= BIT(REQ_F_CREDS_BIT),
+	/* skip refcounting if not set */
+	REQ_F_REFCOUNT		= BIT(REQ_F_REFCOUNT_BIT),
+	/* there is a linked timeout that has to be armed */
+	REQ_F_ARM_LTIMEOUT	= BIT(REQ_F_ARM_LTIMEOUT_BIT),
+	/* ->async_data allocated */
+	REQ_F_ASYNC_DATA	= BIT(REQ_F_ASYNC_DATA_BIT),
+	/* don't post CQEs while failing linked requests */
+	REQ_F_SKIP_LINK_CQES	= BIT(REQ_F_SKIP_LINK_CQES_BIT),
+	/* single poll may be active */
+	REQ_F_SINGLE_POLL	= BIT(REQ_F_SINGLE_POLL_BIT),
+	/* double poll may active */
+	REQ_F_DOUBLE_POLL	= BIT(REQ_F_DOUBLE_POLL_BIT),
+	/* request has already done partial IO */
+	REQ_F_PARTIAL_IO	= BIT(REQ_F_PARTIAL_IO_BIT),
+	/* fast poll multishot mode */
+	REQ_F_APOLL_MULTISHOT	= BIT(REQ_F_APOLL_MULTISHOT_BIT),
+	/* ->extra1 and ->extra2 are initialised */
+	REQ_F_CQE32_INIT	= BIT(REQ_F_CQE32_INIT_BIT),
+};
+
+struct async_poll {
+	struct io_poll_iocb	poll;
+	struct io_poll_iocb	*double_poll;
+};
+
+typedef void (*io_req_tw_func_t)(struct io_kiocb *req, bool *locked);
+
+struct io_task_work {
+	union {
+		struct io_wq_work_node	node;
+		struct llist_node	fallback_node;
+	};
+	io_req_tw_func_t		func;
+};
+
+enum {
+	IORING_RSRC_FILE		= 0,
+	IORING_RSRC_BUFFER		= 1,
+};
+
+struct io_cqe {
+	__u64	user_data;
+	__s32	res;
+	/* fd initially, then cflags for completion */
+	union {
+		__u32	flags;
+		int	fd;
+	};
+};
+
+enum {
+	IO_CHECK_CQ_OVERFLOW_BIT,
+	IO_CHECK_CQ_DROPPED_BIT,
+};
+
+/*
+ * NOTE! Each of the iocb union members has the file pointer
+ * as the first entry in their struct definition. So you can
+ * access the file pointer through any of the sub-structs,
+ * or directly as just 'file' in this struct.
+ */
+struct io_kiocb {
+	union {
+		struct file		*file;
+		struct io_rw		rw;
+		struct io_poll_iocb	poll;
+		struct io_poll_update	poll_update;
+		struct io_accept	accept;
+		struct io_sync		sync;
+		struct io_cancel	cancel;
+		struct io_timeout	timeout;
+		struct io_timeout_rem	timeout_rem;
+		struct io_connect	connect;
+		struct io_sr_msg	sr_msg;
+		struct io_open		open;
+		struct io_close		close;
+		struct io_rsrc_update	rsrc_update;
+		struct io_fadvise	fadvise;
+		struct io_madvise	madvise;
+		struct io_epoll		epoll;
+		struct io_splice	splice;
+		struct io_provide_buf	pbuf;
+		struct io_statx		statx;
+		struct io_shutdown	shutdown;
+		struct io_rename	rename;
+		struct io_unlink	unlink;
+		struct io_mkdir		mkdir;
+		struct io_symlink	symlink;
+		struct io_hardlink	hardlink;
+		struct io_msg		msg;
+		struct io_xattr		xattr;
+		struct io_socket	sock;
+		struct io_uring_cmd	uring_cmd;
+	};
+
+	u8				opcode;
+	/* polled IO has completed */
+	u8				iopoll_completed;
+	/*
+	 * Can be either a fixed buffer index, or used with provided buffers.
+	 * For the latter, before issue it points to the buffer group ID,
+	 * and after selection it points to the buffer ID itself.
+	 */
+	u16				buf_index;
+	unsigned int			flags;
+
+	struct io_cqe			cqe;
+
+	struct io_ring_ctx		*ctx;
+	struct task_struct		*task;
+
+	struct io_rsrc_node		*rsrc_node;
+
+	union {
+		/* store used ubuf, so we can prevent reloading */
+		struct io_mapped_ubuf	*imu;
+
+		/* stores selected buf, valid IFF REQ_F_BUFFER_SELECTED is set */
+		struct io_buffer	*kbuf;
+
+		/*
+		 * stores buffer ID for ring provided buffers, valid IFF
+		 * REQ_F_BUFFER_RING is set.
+		 */
+		struct io_buffer_list	*buf_list;
+	};
+
+	union {
+		/* used by request caches, completion batching and iopoll */
+		struct io_wq_work_node	comp_list;
+		/* cache ->apoll->events */
+		__poll_t apoll_events;
+	};
+	atomic_t			refs;
+	atomic_t			poll_refs;
+	struct io_task_work		io_task_work;
+	/* for polled requests, i.e. IORING_OP_POLL_ADD and async armed poll */
+	union {
+		struct hlist_node	hash_node;
+		struct {
+			u64		extra1;
+			u64		extra2;
+		};
+	};
+	/* internal polling, see IORING_FEAT_FAST_POLL */
+	struct async_poll		*apoll;
+	/* opcode allocated if it needs to store data for async defer */
+	void				*async_data;
+	/* linked requests, IFF REQ_F_HARDLINK or REQ_F_LINK are set */
+	struct io_kiocb			*link;
+	/* custom credentials, valid IFF REQ_F_CREDS is set */
+	const struct cred		*creds;
+	struct io_wq_work		work;
+};
+
+struct io_tctx_node {
+	struct list_head	ctx_node;
+	struct task_struct	*task;
+	struct io_ring_ctx	*ctx;
+};
+
+struct io_defer_entry {
+	struct list_head	list;
+	struct io_kiocb		*req;
+	u32			seq;
+};
+
+struct io_cancel_data {
+	struct io_ring_ctx *ctx;
+	union {
+		u64 data;
+		struct file *file;
+	};
+	u32 flags;
+	int seq;
+};
+
+/*
+ * The URING_CMD payload starts at 'cmd' in the first sqe, and continues into
+ * the following sqe if SQE128 is used.
+ */
+#define uring_cmd_pdu_size(is_sqe128)				\
+	((1 + !!(is_sqe128)) * sizeof(struct io_uring_sqe) -	\
+		offsetof(struct io_uring_sqe, cmd))
+
+struct io_op_def {
+	/* needs req->file assigned */
+	unsigned		needs_file : 1;
+	/* should block plug */
+	unsigned		plug : 1;
+	/* hash wq insertion if file is a regular file */
+	unsigned		hash_reg_file : 1;
+	/* unbound wq insertion if file is a non-regular file */
+	unsigned		unbound_nonreg_file : 1;
+	/* set if opcode supports polled "wait" */
+	unsigned		pollin : 1;
+	unsigned		pollout : 1;
+	unsigned		poll_exclusive : 1;
+	/* op supports buffer selection */
+	unsigned		buffer_select : 1;
+	/* do prep async if is going to be punted */
+	unsigned		needs_async_setup : 1;
+	/* opcode is not supported by this kernel */
+	unsigned		not_supported : 1;
+	/* skip auditing */
+	unsigned		audit_skip : 1;
+	/* supports ioprio */
+	unsigned		ioprio : 1;
+	/* supports iopoll */
+	unsigned		iopoll : 1;
+	/* size of async data needed, if any */
+	unsigned short		async_size;
+
+	int (*prep)(struct io_kiocb *, const struct io_uring_sqe *);
+	int (*issue)(struct io_kiocb *, unsigned int);
+};
+
+static const struct io_op_def io_op_defs[];
+
+/* requests with any of those set should undergo io_disarm_next() */
+#define IO_DISARM_MASK (REQ_F_ARM_LTIMEOUT | REQ_F_LINK_TIMEOUT | REQ_F_FAIL)
+#define IO_REQ_LINK_FLAGS (REQ_F_LINK | REQ_F_HARDLINK)
+
+static bool io_disarm_next(struct io_kiocb *req);
+static void io_uring_del_tctx_node(unsigned long index);
+static void io_uring_try_cancel_requests(struct io_ring_ctx *ctx,
+					 struct task_struct *task,
+					 bool cancel_all);
+static void io_uring_cancel_generic(bool cancel_all, struct io_sq_data *sqd);
+
+static void __io_req_complete_post(struct io_kiocb *req, s32 res, u32 cflags);
+static void io_dismantle_req(struct io_kiocb *req);
+static void io_queue_linked_timeout(struct io_kiocb *req);
+static int __io_register_rsrc_update(struct io_ring_ctx *ctx, unsigned type,
+				     struct io_uring_rsrc_update2 *up,
+				     unsigned nr_args);
+static void io_clean_op(struct io_kiocb *req);
+static inline struct file *io_file_get_fixed(struct io_kiocb *req, int fd,
+					     unsigned issue_flags);
+static struct file *io_file_get_normal(struct io_kiocb *req, int fd);
+static void io_queue_sqe(struct io_kiocb *req);
+static void io_rsrc_put_work(struct work_struct *work);
+
+static void io_req_task_queue(struct io_kiocb *req);
+static void __io_submit_flush_completions(struct io_ring_ctx *ctx);
+static int io_req_prep_async(struct io_kiocb *req);
+
+static int io_install_fixed_file(struct io_kiocb *req, struct file *file,
+				 unsigned int issue_flags, u32 slot_index);
+static int __io_close_fixed(struct io_kiocb *req, unsigned int issue_flags,
+			    unsigned int offset);
+static inline int io_close_fixed(struct io_kiocb *req, unsigned int issue_flags);
+
+static enum hrtimer_restart io_link_timeout_fn(struct hrtimer *timer);
+static void io_eventfd_signal(struct io_ring_ctx *ctx);
+static void io_req_tw_post_queue(struct io_kiocb *req, s32 res, u32 cflags);
+
+static struct kmem_cache *req_cachep;
+
+static const struct file_operations io_uring_fops;
+
+const char *io_uring_get_opcode(u8 opcode)
+{
+	switch ((enum io_uring_op)opcode) {
+	case IORING_OP_NOP:
+		return "NOP";
+	case IORING_OP_READV:
+		return "READV";
+	case IORING_OP_WRITEV:
+		return "WRITEV";
+	case IORING_OP_FSYNC:
+		return "FSYNC";
+	case IORING_OP_READ_FIXED:
+		return "READ_FIXED";
+	case IORING_OP_WRITE_FIXED:
+		return "WRITE_FIXED";
+	case IORING_OP_POLL_ADD:
+		return "POLL_ADD";
+	case IORING_OP_POLL_REMOVE:
+		return "POLL_REMOVE";
+	case IORING_OP_SYNC_FILE_RANGE:
+		return "SYNC_FILE_RANGE";
+	case IORING_OP_SENDMSG:
+		return "SENDMSG";
+	case IORING_OP_RECVMSG:
+		return "RECVMSG";
+	case IORING_OP_TIMEOUT:
+		return "TIMEOUT";
+	case IORING_OP_TIMEOUT_REMOVE:
+		return "TIMEOUT_REMOVE";
+	case IORING_OP_ACCEPT:
+		return "ACCEPT";
+	case IORING_OP_ASYNC_CANCEL:
+		return "ASYNC_CANCEL";
+	case IORING_OP_LINK_TIMEOUT:
+		return "LINK_TIMEOUT";
+	case IORING_OP_CONNECT:
+		return "CONNECT";
+	case IORING_OP_FALLOCATE:
+		return "FALLOCATE";
+	case IORING_OP_OPENAT:
+		return "OPENAT";
+	case IORING_OP_CLOSE:
+		return "CLOSE";
+	case IORING_OP_FILES_UPDATE:
+		return "FILES_UPDATE";
+	case IORING_OP_STATX:
+		return "STATX";
+	case IORING_OP_READ:
+		return "READ";
+	case IORING_OP_WRITE:
+		return "WRITE";
+	case IORING_OP_FADVISE:
+		return "FADVISE";
+	case IORING_OP_MADVISE:
+		return "MADVISE";
+	case IORING_OP_SEND:
+		return "SEND";
+	case IORING_OP_RECV:
+		return "RECV";
+	case IORING_OP_OPENAT2:
+		return "OPENAT2";
+	case IORING_OP_EPOLL_CTL:
+		return "EPOLL_CTL";
+	case IORING_OP_SPLICE:
+		return "SPLICE";
+	case IORING_OP_PROVIDE_BUFFERS:
+		return "PROVIDE_BUFFERS";
+	case IORING_OP_REMOVE_BUFFERS:
+		return "REMOVE_BUFFERS";
+	case IORING_OP_TEE:
+		return "TEE";
+	case IORING_OP_SHUTDOWN:
+		return "SHUTDOWN";
+	case IORING_OP_RENAMEAT:
+		return "RENAMEAT";
+	case IORING_OP_UNLINKAT:
+		return "UNLINKAT";
+	case IORING_OP_MKDIRAT:
+		return "MKDIRAT";
+	case IORING_OP_SYMLINKAT:
+		return "SYMLINKAT";
+	case IORING_OP_LINKAT:
+		return "LINKAT";
+	case IORING_OP_MSG_RING:
+		return "MSG_RING";
+	case IORING_OP_FSETXATTR:
+		return "FSETXATTR";
+	case IORING_OP_SETXATTR:
+		return "SETXATTR";
+	case IORING_OP_FGETXATTR:
+		return "FGETXATTR";
+	case IORING_OP_GETXATTR:
+		return "GETXATTR";
+	case IORING_OP_SOCKET:
+		return "SOCKET";
+	case IORING_OP_URING_CMD:
+		return "URING_CMD";
+	case IORING_OP_LAST:
+		return "INVALID";
+	}
+	return "INVALID";
+}
+
+struct sock *io_uring_get_socket(struct file *file)
+{
+#if defined(CONFIG_UNIX)
+	if (file->f_op == &io_uring_fops) {
+		struct io_ring_ctx *ctx = file->private_data;
+
+		return ctx->ring_sock->sk;
+	}
+#endif
+	return NULL;
+}
+EXPORT_SYMBOL(io_uring_get_socket);
+
+#if defined(CONFIG_UNIX)
+static inline bool io_file_need_scm(struct file *filp)
+{
+#if defined(IO_URING_SCM_ALL)
+	return true;
+#else
+	return !!unix_get_socket(filp);
+#endif
+}
+#else
+static inline bool io_file_need_scm(struct file *filp)
+{
+	return false;
+}
+#endif
+
+static void io_ring_submit_unlock(struct io_ring_ctx *ctx, unsigned issue_flags)
+{
+	lockdep_assert_held(&ctx->uring_lock);
+	if (issue_flags & IO_URING_F_UNLOCKED)
+		mutex_unlock(&ctx->uring_lock);
+}
+
+static void io_ring_submit_lock(struct io_ring_ctx *ctx, unsigned issue_flags)
+{
+	/*
+	 * "Normal" inline submissions always hold the uring_lock, since we
+	 * grab it from the system call. Same is true for the SQPOLL offload.
+	 * The only exception is when we've detached the request and issue it
+	 * from an async worker thread, grab the lock for that case.
+	 */
+	if (issue_flags & IO_URING_F_UNLOCKED)
+		mutex_lock(&ctx->uring_lock);
+	lockdep_assert_held(&ctx->uring_lock);
+}
+
+static inline void io_tw_lock(struct io_ring_ctx *ctx, bool *locked)
+{
+	if (!*locked) {
+		mutex_lock(&ctx->uring_lock);
+		*locked = true;
+	}
+}
+
+#define io_for_each_link(pos, head) \
+	for (pos = (head); pos; pos = pos->link)
+
+/*
+ * Shamelessly stolen from the mm implementation of page reference checking,
+ * see commit f958d7b528b1 for details.
+ */
+#define req_ref_zero_or_close_to_overflow(req)	\
+	((unsigned int) atomic_read(&(req->refs)) + 127u <= 127u)
+
+static inline bool req_ref_inc_not_zero(struct io_kiocb *req)
+{
+	WARN_ON_ONCE(!(req->flags & REQ_F_REFCOUNT));
+	return atomic_inc_not_zero(&req->refs);
+}
+
+static inline bool req_ref_put_and_test(struct io_kiocb *req)
+{
+	if (likely(!(req->flags & REQ_F_REFCOUNT)))
+		return true;
+
+	WARN_ON_ONCE(req_ref_zero_or_close_to_overflow(req));
+	return atomic_dec_and_test(&req->refs);
+}
+
+static inline void req_ref_get(struct io_kiocb *req)
+{
+	WARN_ON_ONCE(!(req->flags & REQ_F_REFCOUNT));
+	WARN_ON_ONCE(req_ref_zero_or_close_to_overflow(req));
+	atomic_inc(&req->refs);
+}
+
+static inline void io_submit_flush_completions(struct io_ring_ctx *ctx)
+{
+	if (!wq_list_empty(&ctx->submit_state.compl_reqs))
+		__io_submit_flush_completions(ctx);
+}
+
+static inline void __io_req_set_refcount(struct io_kiocb *req, int nr)
+{
+	if (!(req->flags & REQ_F_REFCOUNT)) {
+		req->flags |= REQ_F_REFCOUNT;
+		atomic_set(&req->refs, nr);
+	}
+}
+
+static inline void io_req_set_refcount(struct io_kiocb *req)
+{
+	__io_req_set_refcount(req, 1);
+}
+
+#define IO_RSRC_REF_BATCH	100
+
+static void io_rsrc_put_node(struct io_rsrc_node *node, int nr)
+{
+	percpu_ref_put_many(&node->refs, nr);
+}
+
+static inline void io_req_put_rsrc_locked(struct io_kiocb *req,
+					  struct io_ring_ctx *ctx)
+	__must_hold(&ctx->uring_lock)
+{
+	struct io_rsrc_node *node = req->rsrc_node;
+
+	if (node) {
+		if (node == ctx->rsrc_node)
+			ctx->rsrc_cached_refs++;
+		else
+			io_rsrc_put_node(node, 1);
+	}
+}
+
+static inline void io_req_put_rsrc(struct io_kiocb *req)
+{
+	if (req->rsrc_node)
+		io_rsrc_put_node(req->rsrc_node, 1);
+}
+
+static __cold void io_rsrc_refs_drop(struct io_ring_ctx *ctx)
+	__must_hold(&ctx->uring_lock)
+{
+	if (ctx->rsrc_cached_refs) {
+		io_rsrc_put_node(ctx->rsrc_node, ctx->rsrc_cached_refs);
+		ctx->rsrc_cached_refs = 0;
+	}
+}
+
+static void io_rsrc_refs_refill(struct io_ring_ctx *ctx)
+	__must_hold(&ctx->uring_lock)
+{
+	ctx->rsrc_cached_refs += IO_RSRC_REF_BATCH;
+	percpu_ref_get_many(&ctx->rsrc_node->refs, IO_RSRC_REF_BATCH);
+}
+
+static inline void io_req_set_rsrc_node(struct io_kiocb *req,
+					struct io_ring_ctx *ctx,
+					unsigned int issue_flags)
+{
+	if (!req->rsrc_node) {
+		req->rsrc_node = ctx->rsrc_node;
+
+		if (!(issue_flags & IO_URING_F_UNLOCKED)) {
+			lockdep_assert_held(&ctx->uring_lock);
+			ctx->rsrc_cached_refs--;
+			if (unlikely(ctx->rsrc_cached_refs < 0))
+				io_rsrc_refs_refill(ctx);
+		} else {
+			percpu_ref_get(&req->rsrc_node->refs);
+		}
+	}
+}
+
+static unsigned int __io_put_kbuf(struct io_kiocb *req, struct list_head *list)
+{
+	if (req->flags & REQ_F_BUFFER_RING) {
+		if (req->buf_list)
+			req->buf_list->head++;
+		req->flags &= ~REQ_F_BUFFER_RING;
+	} else {
+		list_add(&req->kbuf->list, list);
+		req->flags &= ~REQ_F_BUFFER_SELECTED;
+	}
+
+	return IORING_CQE_F_BUFFER | (req->buf_index << IORING_CQE_BUFFER_SHIFT);
+}
+
+static inline unsigned int io_put_kbuf_comp(struct io_kiocb *req)
+{
+	lockdep_assert_held(&req->ctx->completion_lock);
+
+	if (!(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING)))
+		return 0;
+	return __io_put_kbuf(req, &req->ctx->io_buffers_comp);
+}
+
+static inline unsigned int io_put_kbuf(struct io_kiocb *req,
+				       unsigned issue_flags)
+{
+	unsigned int cflags;
+
+	if (!(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING)))
+		return 0;
+
+	/*
+	 * We can add this buffer back to two lists:
+	 *
+	 * 1) The io_buffers_cache list. This one is protected by the
+	 *    ctx->uring_lock. If we already hold this lock, add back to this
+	 *    list as we can grab it from issue as well.
+	 * 2) The io_buffers_comp list. This one is protected by the
+	 *    ctx->completion_lock.
+	 *
+	 * We migrate buffers from the comp_list to the issue cache list
+	 * when we need one.
+	 */
+	if (req->flags & REQ_F_BUFFER_RING) {
+		/* no buffers to recycle for this case */
+		cflags = __io_put_kbuf(req, NULL);
+	} else if (issue_flags & IO_URING_F_UNLOCKED) {
+		struct io_ring_ctx *ctx = req->ctx;
+
+		spin_lock(&ctx->completion_lock);
+		cflags = __io_put_kbuf(req, &ctx->io_buffers_comp);
+		spin_unlock(&ctx->completion_lock);
+	} else {
+		lockdep_assert_held(&req->ctx->uring_lock);
+
+		cflags = __io_put_kbuf(req, &req->ctx->io_buffers_cache);
+	}
+
+	return cflags;
+}
+
+static struct io_buffer_list *io_buffer_get_list(struct io_ring_ctx *ctx,
+						 unsigned int bgid)
+{
+	if (ctx->io_bl && bgid < BGID_ARRAY)
+		return &ctx->io_bl[bgid];
+
+	return xa_load(&ctx->io_bl_xa, bgid);
+}
+
+static void io_kbuf_recycle(struct io_kiocb *req, unsigned issue_flags)
+{
+	struct io_ring_ctx *ctx = req->ctx;
+	struct io_buffer_list *bl;
+	struct io_buffer *buf;
+
+	if (!(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING)))
+		return;
+	/*
+	 * For legacy provided buffer mode, don't recycle if we already did
+	 * IO to this buffer. For ring-mapped provided buffer mode, we should
+	 * increment ring->head to explicitly monopolize the buffer to avoid
+	 * multiple use.
+	 */
+	if ((req->flags & REQ_F_BUFFER_SELECTED) &&
+	    (req->flags & REQ_F_PARTIAL_IO))
+		return;
+
+	/*
+	 * READV uses fields in `struct io_rw` (len/addr) to stash the selected
+	 * buffer data. However if that buffer is recycled the original request
+	 * data stored in addr is lost. Therefore forbid recycling for now.
+	 */
+	if (req->opcode == IORING_OP_READV)
+		return;
+
+	/*
+	 * We don't need to recycle for REQ_F_BUFFER_RING, we can just clear
+	 * the flag and hence ensure that bl->head doesn't get incremented.
+	 * If the tail has already been incremented, hang on to it.
+	 */
+	if (req->flags & REQ_F_BUFFER_RING) {
+		if (req->buf_list) {
+			if (req->flags & REQ_F_PARTIAL_IO) {
+				req->buf_list->head++;
+				req->buf_list = NULL;
+			} else {
+				req->buf_index = req->buf_list->bgid;
+				req->flags &= ~REQ_F_BUFFER_RING;
+			}
+		}
+		return;
+	}
+
+	io_ring_submit_lock(ctx, issue_flags);
+
+	buf = req->kbuf;
+	bl = io_buffer_get_list(ctx, buf->bgid);
+	list_add(&buf->list, &bl->buf_list);
+	req->flags &= ~REQ_F_BUFFER_SELECTED;
+	req->buf_index = buf->bgid;
+
+	io_ring_submit_unlock(ctx, issue_flags);
+}
+
+static bool io_match_task(struct io_kiocb *head, struct task_struct *task,
+			  bool cancel_all)
+	__must_hold(&req->ctx->timeout_lock)
+{
+	struct io_kiocb *req;
+
+	if (task && head->task != task)
+		return false;
+	if (cancel_all)
+		return true;
+
+	io_for_each_link(req, head) {
+		if (req->flags & REQ_F_INFLIGHT)
+			return true;
+	}
+	return false;
+}
+
+static bool io_match_linked(struct io_kiocb *head)
+{
+	struct io_kiocb *req;
+
+	io_for_each_link(req, head) {
+		if (req->flags & REQ_F_INFLIGHT)
+			return true;
+	}
+	return false;
+}
+
+/*
+ * As io_match_task() but protected against racing with linked timeouts.
+ * User must not hold timeout_lock.
+ */
+static bool io_match_task_safe(struct io_kiocb *head, struct task_struct *task,
+			       bool cancel_all)
+{
+	bool matched;
+
+	if (task && head->task != task)
+		return false;
+	if (cancel_all)
+		return true;
+
+	if (head->flags & REQ_F_LINK_TIMEOUT) {
+		struct io_ring_ctx *ctx = head->ctx;
+
+		/* protect against races with linked timeouts */
+		spin_lock_irq(&ctx->timeout_lock);
+		matched = io_match_linked(head);
+		spin_unlock_irq(&ctx->timeout_lock);
+	} else {
+		matched = io_match_linked(head);
+	}
+	return matched;
+}
+
+static inline bool req_has_async_data(struct io_kiocb *req)
+{
+	return req->flags & REQ_F_ASYNC_DATA;
+}
+
+static inline void req_set_fail(struct io_kiocb *req)
+{
+	req->flags |= REQ_F_FAIL;
+	if (req->flags & REQ_F_CQE_SKIP) {
+		req->flags &= ~REQ_F_CQE_SKIP;
+		req->flags |= REQ_F_SKIP_LINK_CQES;
+	}
+}
+
+static inline void req_fail_link_node(struct io_kiocb *req, int res)
+{
+	req_set_fail(req);
+	req->cqe.res = res;
+}
+
+static inline void io_req_add_to_cache(struct io_kiocb *req, struct io_ring_ctx *ctx)
+{
+	wq_stack_add_head(&req->comp_list, &ctx->submit_state.free_list);
+}
+
+static __cold void io_ring_ctx_ref_free(struct percpu_ref *ref)
+{
+	struct io_ring_ctx *ctx = container_of(ref, struct io_ring_ctx, refs);
+
+	complete(&ctx->ref_comp);
+}
+
+static inline bool io_is_timeout_noseq(struct io_kiocb *req)
+{
+	return !req->timeout.off;
+}
+
+static __cold void io_fallback_req_func(struct work_struct *work)
+{
+	struct io_ring_ctx *ctx = container_of(work, struct io_ring_ctx,
+						fallback_work.work);
+	struct llist_node *node = llist_del_all(&ctx->fallback_llist);
+	struct io_kiocb *req, *tmp;
+	bool locked = false;
+
+	percpu_ref_get(&ctx->refs);
+	llist_for_each_entry_safe(req, tmp, node, io_task_work.fallback_node)
+		req->io_task_work.func(req, &locked);
+
+	if (locked) {
+		io_submit_flush_completions(ctx);
+		mutex_unlock(&ctx->uring_lock);
+	}
+	percpu_ref_put(&ctx->refs);
+}
+
+static __cold struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p)
+{
+	struct io_ring_ctx *ctx;
+	int hash_bits;
+
+	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
+	if (!ctx)
+		return NULL;
+
+	xa_init(&ctx->io_bl_xa);
+
+	/*
+	 * Use 5 bits less than the max cq entries, that should give us around
+	 * 32 entries per hash list if totally full and uniformly spread.
+	 */
+	hash_bits = ilog2(p->cq_entries);
+	hash_bits -= 5;
+	if (hash_bits <= 0)
+		hash_bits = 1;
+	ctx->cancel_hash_bits = hash_bits;
+	ctx->cancel_hash = kmalloc((1U << hash_bits) * sizeof(struct hlist_head),
+					GFP_KERNEL);
+	if (!ctx->cancel_hash)
+		goto err;
+	__hash_init(ctx->cancel_hash, 1U << hash_bits);
+
+	ctx->dummy_ubuf = kzalloc(sizeof(*ctx->dummy_ubuf), GFP_KERNEL);
+	if (!ctx->dummy_ubuf)
+		goto err;
+	/* set invalid range, so io_import_fixed() fails meeting it */
+	ctx->dummy_ubuf->ubuf = -1UL;
+
+	if (percpu_ref_init(&ctx->refs, io_ring_ctx_ref_free,
+			    PERCPU_REF_ALLOW_REINIT, GFP_KERNEL))
+		goto err;
+
+	ctx->flags = p->flags;
+	init_waitqueue_head(&ctx->sqo_sq_wait);
+	INIT_LIST_HEAD(&ctx->sqd_list);
+	INIT_LIST_HEAD(&ctx->cq_overflow_list);
+	INIT_LIST_HEAD(&ctx->io_buffers_cache);
+	INIT_LIST_HEAD(&ctx->apoll_cache);
+	init_completion(&ctx->ref_comp);
+	xa_init_flags(&ctx->personalities, XA_FLAGS_ALLOC1);
+	mutex_init(&ctx->uring_lock);
+	init_waitqueue_head(&ctx->cq_wait);
+	spin_lock_init(&ctx->completion_lock);
+	spin_lock_init(&ctx->timeout_lock);
+	INIT_WQ_LIST(&ctx->iopoll_list);
+	INIT_LIST_HEAD(&ctx->io_buffers_pages);
+	INIT_LIST_HEAD(&ctx->io_buffers_comp);
+	INIT_LIST_HEAD(&ctx->defer_list);
+	INIT_LIST_HEAD(&ctx->timeout_list);
+	INIT_LIST_HEAD(&ctx->ltimeout_list);
+	spin_lock_init(&ctx->rsrc_ref_lock);
+	INIT_LIST_HEAD(&ctx->rsrc_ref_list);
+	INIT_DELAYED_WORK(&ctx->rsrc_put_work, io_rsrc_put_work);
+	init_llist_head(&ctx->rsrc_put_llist);
+	INIT_LIST_HEAD(&ctx->tctx_list);
+	ctx->submit_state.free_list.next = NULL;
+	INIT_WQ_LIST(&ctx->locked_free_list);
+	INIT_DELAYED_WORK(&ctx->fallback_work, io_fallback_req_func);
+	INIT_WQ_LIST(&ctx->submit_state.compl_reqs);
+	return ctx;
+err:
+	kfree(ctx->dummy_ubuf);
+	kfree(ctx->cancel_hash);
+	kfree(ctx->io_bl);
+	xa_destroy(&ctx->io_bl_xa);
+	kfree(ctx);
+	return NULL;
+}
+
+static void io_account_cq_overflow(struct io_ring_ctx *ctx)
+{
+	struct io_rings *r = ctx->rings;
+
+	WRITE_ONCE(r->cq_overflow, READ_ONCE(r->cq_overflow) + 1);
+	ctx->cq_extra--;
+}
+
+static bool req_need_defer(struct io_kiocb *req, u32 seq)
+{
+	if (unlikely(req->flags & REQ_F_IO_DRAIN)) {
+		struct io_ring_ctx *ctx = req->ctx;
+
+		return seq + READ_ONCE(ctx->cq_extra) != ctx->cached_cq_tail;
+	}
+
+	return false;
+}
+
+static inline bool io_req_ffs_set(struct io_kiocb *req)
+{
+	return req->flags & REQ_F_FIXED_FILE;
+}
+
+static inline void io_req_track_inflight(struct io_kiocb *req)
+{
+	if (!(req->flags & REQ_F_INFLIGHT)) {
+		req->flags |= REQ_F_INFLIGHT;
+		atomic_inc(&req->task->io_uring->inflight_tracked);
+	}
+}
+
+static struct io_kiocb *__io_prep_linked_timeout(struct io_kiocb *req)
+{
+	if (WARN_ON_ONCE(!req->link))
+		return NULL;
+
+	req->flags &= ~REQ_F_ARM_LTIMEOUT;
+	req->flags |= REQ_F_LINK_TIMEOUT;
+
+	/* linked timeouts should have two refs once prep'ed */
+	io_req_set_refcount(req);
+	__io_req_set_refcount(req->link, 2);
+	return req->link;
+}
+
+static inline struct io_kiocb *io_prep_linked_timeout(struct io_kiocb *req)
+{
+	if (likely(!(req->flags & REQ_F_ARM_LTIMEOUT)))
+		return NULL;
+	return __io_prep_linked_timeout(req);
+}
+
+static noinline void __io_arm_ltimeout(struct io_kiocb *req)
+{
+	io_queue_linked_timeout(__io_prep_linked_timeout(req));
+}
+
+static inline void io_arm_ltimeout(struct io_kiocb *req)
+{
+	if (unlikely(req->flags & REQ_F_ARM_LTIMEOUT))
+		__io_arm_ltimeout(req);
+}
+
+static void io_prep_async_work(struct io_kiocb *req)
+{
+	const struct io_op_def *def = &io_op_defs[req->opcode];
+	struct io_ring_ctx *ctx = req->ctx;
+
+	if (!(req->flags & REQ_F_CREDS)) {
+		req->flags |= REQ_F_CREDS;
+		req->creds = get_current_cred();
+	}
+
+	req->work.list.next = NULL;
+	req->work.flags = 0;
+	req->work.cancel_seq = atomic_read(&ctx->cancel_seq);
+	if (req->flags & REQ_F_FORCE_ASYNC)
+		req->work.flags |= IO_WQ_WORK_CONCURRENT;
+
+	if (req->flags & REQ_F_ISREG) {
+		if (def->hash_reg_file || (ctx->flags & IORING_SETUP_IOPOLL))
+			io_wq_hash_work(&req->work, file_inode(req->file));
+	} else if (!req->file || !S_ISBLK(file_inode(req->file)->i_mode)) {
+		if (def->unbound_nonreg_file)
+			req->work.flags |= IO_WQ_WORK_UNBOUND;
+	}
+}
+
+static void io_prep_async_link(struct io_kiocb *req)
+{
+	struct io_kiocb *cur;
+
+	if (req->flags & REQ_F_LINK_TIMEOUT) {
+		struct io_ring_ctx *ctx = req->ctx;
+
+		spin_lock_irq(&ctx->timeout_lock);
+		io_for_each_link(cur, req)
+			io_prep_async_work(cur);
+		spin_unlock_irq(&ctx->timeout_lock);
+	} else {
+		io_for_each_link(cur, req)
+			io_prep_async_work(cur);
+	}
+}
+
+static inline void io_req_add_compl_list(struct io_kiocb *req)
+{
+	struct io_submit_state *state = &req->ctx->submit_state;
+
+	if (!(req->flags & REQ_F_CQE_SKIP))
+		state->flush_cqes = true;
+	wq_list_add_tail(&req->comp_list, &state->compl_reqs);
+}
+
+static void io_queue_iowq(struct io_kiocb *req, bool *dont_use)
+{
+	struct io_kiocb *link = io_prep_linked_timeout(req);
+	struct io_uring_task *tctx = req->task->io_uring;
+
+	BUG_ON(!tctx);
+	BUG_ON(!tctx->io_wq);
+
+	/* init ->work of the whole link before punting */
+	io_prep_async_link(req);
+
+	/*
+	 * Not expected to happen, but if we do have a bug where this _can_
+	 * happen, catch it here and ensure the request is marked as
+	 * canceled. That will make io-wq go through the usual work cancel
+	 * procedure rather than attempt to run this request (or create a new
+	 * worker for it).
+	 */
+	if (WARN_ON_ONCE(!same_thread_group(req->task, current)))
+		req->work.flags |= IO_WQ_WORK_CANCEL;
+
+	trace_io_uring_queue_async_work(req->ctx, req, req->cqe.user_data,
+					req->opcode, req->flags, &req->work,
+					io_wq_is_hashed(&req->work));
+	io_wq_enqueue(tctx->io_wq, &req->work);
+	if (link)
+		io_queue_linked_timeout(link);
+}
+
+static void io_kill_timeout(struct io_kiocb *req, int status)
+	__must_hold(&req->ctx->completion_lock)
+	__must_hold(&req->ctx->timeout_lock)
+{
+	struct io_timeout_data *io = req->async_data;
+
+	if (hrtimer_try_to_cancel(&io->timer) != -1) {
+		if (status)
+			req_set_fail(req);
+		atomic_set(&req->ctx->cq_timeouts,
+			atomic_read(&req->ctx->cq_timeouts) + 1);
+		list_del_init(&req->timeout.list);
+		io_req_tw_post_queue(req, status, 0);
+	}
+}
+
+static __cold void io_queue_deferred(struct io_ring_ctx *ctx)
+{
+	while (!list_empty(&ctx->defer_list)) {
+		struct io_defer_entry *de = list_first_entry(&ctx->defer_list,
+						struct io_defer_entry, list);
+
+		if (req_need_defer(de->req, de->seq))
+			break;
+		list_del_init(&de->list);
+		io_req_task_queue(de->req);
+		kfree(de);
+	}
+}
+
+static __cold void io_flush_timeouts(struct io_ring_ctx *ctx)
+	__must_hold(&ctx->completion_lock)
+{
+	u32 seq = ctx->cached_cq_tail - atomic_read(&ctx->cq_timeouts);
+	struct io_kiocb *req, *tmp;
+
+	spin_lock_irq(&ctx->timeout_lock);
+	list_for_each_entry_safe(req, tmp, &ctx->timeout_list, timeout.list) {
+		u32 events_needed, events_got;
+
+		if (io_is_timeout_noseq(req))
+			break;
+
+		/*
+		 * Since seq can easily wrap around over time, subtract
+		 * the last seq at which timeouts were flushed before comparing.
+		 * Assuming not more than 2^31-1 events have happened since,
+		 * these subtractions won't have wrapped, so we can check if
+		 * target is in [last_seq, current_seq] by comparing the two.
+		 */
+		events_needed = req->timeout.target_seq - ctx->cq_last_tm_flush;
+		events_got = seq - ctx->cq_last_tm_flush;
+		if (events_got < events_needed)
+			break;
+
+		io_kill_timeout(req, 0);
+	}
+	ctx->cq_last_tm_flush = seq;
+	spin_unlock_irq(&ctx->timeout_lock);
+}
+
+static inline void io_commit_cqring(struct io_ring_ctx *ctx)
+{
+	/* order cqe stores with ring update */
+	smp_store_release(&ctx->rings->cq.tail, ctx->cached_cq_tail);
+}
+
+static void __io_commit_cqring_flush(struct io_ring_ctx *ctx)
+{
+	if (ctx->off_timeout_used || ctx->drain_active) {
+		spin_lock(&ctx->completion_lock);
+		if (ctx->off_timeout_used)
+			io_flush_timeouts(ctx);
+		if (ctx->drain_active)
+			io_queue_deferred(ctx);
+		io_commit_cqring(ctx);
+		spin_unlock(&ctx->completion_lock);
+	}
+	if (ctx->has_evfd)
+		io_eventfd_signal(ctx);
+}
+
+static inline bool io_sqring_full(struct io_ring_ctx *ctx)
+{
+	struct io_rings *r = ctx->rings;
+
+	return READ_ONCE(r->sq.tail) - ctx->cached_sq_head == ctx->sq_entries;
+}
+
+static inline unsigned int __io_cqring_events(struct io_ring_ctx *ctx)
+{
+	return ctx->cached_cq_tail - READ_ONCE(ctx->rings->cq.head);
+}
+
+/*
+ * writes to the cq entry need to come after reading head; the
+ * control dependency is enough as we're using WRITE_ONCE to
+ * fill the cq entry
+ */
+static noinline struct io_uring_cqe *__io_get_cqe(struct io_ring_ctx *ctx)
+{
+	struct io_rings *rings = ctx->rings;
+	unsigned int off = ctx->cached_cq_tail & (ctx->cq_entries - 1);
+	unsigned int shift = 0;
+	unsigned int free, queued, len;
+
+	if (ctx->flags & IORING_SETUP_CQE32)
+		shift = 1;
+
+	/* userspace may cheat modifying the tail, be safe and do min */
+	queued = min(__io_cqring_events(ctx), ctx->cq_entries);
+	free = ctx->cq_entries - queued;
+	/* we need a contiguous range, limit based on the current array offset */
+	len = min(free, ctx->cq_entries - off);
+	if (!len)
+		return NULL;
+
+	ctx->cached_cq_tail++;
+	ctx->cqe_cached = &rings->cqes[off];
+	ctx->cqe_sentinel = ctx->cqe_cached + len;
+	ctx->cqe_cached++;
+	return &rings->cqes[off << shift];
+}
+
+static inline struct io_uring_cqe *io_get_cqe(struct io_ring_ctx *ctx)
+{
+	if (likely(ctx->cqe_cached < ctx->cqe_sentinel)) {
+		struct io_uring_cqe *cqe = ctx->cqe_cached;
+
+		if (ctx->flags & IORING_SETUP_CQE32) {
+			unsigned int off = ctx->cqe_cached - ctx->rings->cqes;
+
+			cqe += off;
+		}
+
+		ctx->cached_cq_tail++;
+		ctx->cqe_cached++;
+		return cqe;
+	}
+
+	return __io_get_cqe(ctx);
+}
+
+static void io_eventfd_signal(struct io_ring_ctx *ctx)
+{
+	struct io_ev_fd *ev_fd;
+
+	rcu_read_lock();
+	/*
+	 * rcu_dereference ctx->io_ev_fd once and use it for both for checking
+	 * and eventfd_signal
+	 */
+	ev_fd = rcu_dereference(ctx->io_ev_fd);
+
+	/*
+	 * Check again if ev_fd exists incase an io_eventfd_unregister call
+	 * completed between the NULL check of ctx->io_ev_fd at the start of
+	 * the function and rcu_read_lock.
+	 */
+	if (unlikely(!ev_fd))
+		goto out;
+	if (READ_ONCE(ctx->rings->cq_flags) & IORING_CQ_EVENTFD_DISABLED)
+		goto out;
+
+	if (!ev_fd->eventfd_async || io_wq_current_is_worker())
+		eventfd_signal(ev_fd->cq_ev_fd, 1);
+out:
+	rcu_read_unlock();
+}
+
+static inline void io_cqring_wake(struct io_ring_ctx *ctx)
+{
+	/*
+	 * wake_up_all() may seem excessive, but io_wake_function() and
+	 * io_should_wake() handle the termination of the loop and only
+	 * wake as many waiters as we need to.
+	 */
+	if (wq_has_sleeper(&ctx->cq_wait))
+		wake_up_all(&ctx->cq_wait);
+}
+
+/*
+ * This should only get called when at least one event has been posted.
+ * Some applications rely on the eventfd notification count only changing
+ * IFF a new CQE has been added to the CQ ring. There's no depedency on
+ * 1:1 relationship between how many times this function is called (and
+ * hence the eventfd count) and number of CQEs posted to the CQ ring.
+ */
+static inline void io_cqring_ev_posted(struct io_ring_ctx *ctx)
+{
+	if (unlikely(ctx->off_timeout_used || ctx->drain_active ||
+		     ctx->has_evfd))
+		__io_commit_cqring_flush(ctx);
+
+	io_cqring_wake(ctx);
+}
+
+static void io_cqring_ev_posted_iopoll(struct io_ring_ctx *ctx)
+{
+	if (unlikely(ctx->off_timeout_used || ctx->drain_active ||
+		     ctx->has_evfd))
+		__io_commit_cqring_flush(ctx);
+
+	if (ctx->flags & IORING_SETUP_SQPOLL)
+		io_cqring_wake(ctx);
+}
+
+/* Returns true if there are no backlogged entries after the flush */
+static bool __io_cqring_overflow_flush(struct io_ring_ctx *ctx, bool force)
+{
+	bool all_flushed, posted;
+	size_t cqe_size = sizeof(struct io_uring_cqe);
+
+	if (!force && __io_cqring_events(ctx) == ctx->cq_entries)
+		return false;
+
+	if (ctx->flags & IORING_SETUP_CQE32)
+		cqe_size <<= 1;
+
+	posted = false;
+	spin_lock(&ctx->completion_lock);
+	while (!list_empty(&ctx->cq_overflow_list)) {
+		struct io_uring_cqe *cqe = io_get_cqe(ctx);
+		struct io_overflow_cqe *ocqe;
+
+		if (!cqe && !force)
+			break;
+		ocqe = list_first_entry(&ctx->cq_overflow_list,
+					struct io_overflow_cqe, list);
+		if (cqe)
+			memcpy(cqe, &ocqe->cqe, cqe_size);
+		else
+			io_account_cq_overflow(ctx);
+
+		posted = true;
+		list_del(&ocqe->list);
+		kfree(ocqe);
+	}
+
+	all_flushed = list_empty(&ctx->cq_overflow_list);
+	if (all_flushed) {
+		clear_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq);
+		atomic_andnot(IORING_SQ_CQ_OVERFLOW, &ctx->rings->sq_flags);
+	}
+
+	io_commit_cqring(ctx);
+	spin_unlock(&ctx->completion_lock);
+	if (posted)
+		io_cqring_ev_posted(ctx);
+	return all_flushed;
+}
+
+static bool io_cqring_overflow_flush(struct io_ring_ctx *ctx)
+{
+	bool ret = true;
+
+	if (test_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq)) {
+		/* iopoll syncs against uring_lock, not completion_lock */
+		if (ctx->flags & IORING_SETUP_IOPOLL)
+			mutex_lock(&ctx->uring_lock);
+		ret = __io_cqring_overflow_flush(ctx, false);
+		if (ctx->flags & IORING_SETUP_IOPOLL)
+			mutex_unlock(&ctx->uring_lock);
+	}
+
+	return ret;
+}
+
+static void __io_put_task(struct task_struct *task, int nr)
+{
+	struct io_uring_task *tctx = task->io_uring;
+
+	percpu_counter_sub(&tctx->inflight, nr);
+	if (unlikely(atomic_read(&tctx->in_idle)))
+		wake_up(&tctx->wait);
+	put_task_struct_many(task, nr);
+}
+
+/* must to be called somewhat shortly after putting a request */
+static inline void io_put_task(struct task_struct *task, int nr)
+{
+	if (likely(task == current))
+		task->io_uring->cached_refs += nr;
+	else
+		__io_put_task(task, nr);
+}
+
+static void io_task_refs_refill(struct io_uring_task *tctx)
+{
+	unsigned int refill = -tctx->cached_refs + IO_TCTX_REFS_CACHE_NR;
+
+	percpu_counter_add(&tctx->inflight, refill);
+	refcount_add(refill, &current->usage);
+	tctx->cached_refs += refill;
+}
+
+static inline void io_get_task_refs(int nr)
+{
+	struct io_uring_task *tctx = current->io_uring;
+
+	tctx->cached_refs -= nr;
+	if (unlikely(tctx->cached_refs < 0))
+		io_task_refs_refill(tctx);
+}
+
+static __cold void io_uring_drop_tctx_refs(struct task_struct *task)
+{
+	struct io_uring_task *tctx = task->io_uring;
+	unsigned int refs = tctx->cached_refs;
+
+	if (refs) {
+		tctx->cached_refs = 0;
+		percpu_counter_sub(&tctx->inflight, refs);
+		put_task_struct_many(task, refs);
+	}
+}
+
+static bool io_cqring_event_overflow(struct io_ring_ctx *ctx, u64 user_data,
+				     s32 res, u32 cflags, u64 extra1,
+				     u64 extra2)
+{
+	struct io_overflow_cqe *ocqe;
+	size_t ocq_size = sizeof(struct io_overflow_cqe);
+	bool is_cqe32 = (ctx->flags & IORING_SETUP_CQE32);
+
+	if (is_cqe32)
+		ocq_size += sizeof(struct io_uring_cqe);
+
+	ocqe = kmalloc(ocq_size, GFP_ATOMIC | __GFP_ACCOUNT);
+	trace_io_uring_cqe_overflow(ctx, user_data, res, cflags, ocqe);
+	if (!ocqe) {
+		/*
+		 * If we're in ring overflow flush mode, or in task cancel mode,
+		 * or cannot allocate an overflow entry, then we need to drop it
+		 * on the floor.
+		 */
+		io_account_cq_overflow(ctx);
+		set_bit(IO_CHECK_CQ_DROPPED_BIT, &ctx->check_cq);
+		return false;
+	}
+	if (list_empty(&ctx->cq_overflow_list)) {
+		set_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq);
+		atomic_or(IORING_SQ_CQ_OVERFLOW, &ctx->rings->sq_flags);
+
+	}
+	ocqe->cqe.user_data = user_data;
+	ocqe->cqe.res = res;
+	ocqe->cqe.flags = cflags;
+	if (is_cqe32) {
+		ocqe->cqe.big_cqe[0] = extra1;
+		ocqe->cqe.big_cqe[1] = extra2;
+	}
+	list_add_tail(&ocqe->list, &ctx->cq_overflow_list);
+	return true;
+}
+
+static inline bool __io_fill_cqe_req(struct io_ring_ctx *ctx,
+				     struct io_kiocb *req)
+{
+	struct io_uring_cqe *cqe;
+
+	if (!(ctx->flags & IORING_SETUP_CQE32)) {
+		trace_io_uring_complete(req->ctx, req, req->cqe.user_data,
+					req->cqe.res, req->cqe.flags, 0, 0);
+
+		/*
+		 * If we can't get a cq entry, userspace overflowed the
+		 * submission (by quite a lot). Increment the overflow count in
+		 * the ring.
+		 */
+		cqe = io_get_cqe(ctx);
+		if (likely(cqe)) {
+			memcpy(cqe, &req->cqe, sizeof(*cqe));
+			return true;
+		}
+
+		return io_cqring_event_overflow(ctx, req->cqe.user_data,
+						req->cqe.res, req->cqe.flags,
+						0, 0);
+	} else {
+		u64 extra1 = 0, extra2 = 0;
+
+		if (req->flags & REQ_F_CQE32_INIT) {
+			extra1 = req->extra1;
+			extra2 = req->extra2;
+		}
+
+		trace_io_uring_complete(req->ctx, req, req->cqe.user_data,
+					req->cqe.res, req->cqe.flags, extra1, extra2);
+
+		/*
+		 * If we can't get a cq entry, userspace overflowed the
+		 * submission (by quite a lot). Increment the overflow count in
+		 * the ring.
+		 */
+		cqe = io_get_cqe(ctx);
+		if (likely(cqe)) {
+			memcpy(cqe, &req->cqe, sizeof(struct io_uring_cqe));
+			WRITE_ONCE(cqe->big_cqe[0], extra1);
+			WRITE_ONCE(cqe->big_cqe[1], extra2);
+			return true;
+		}
+
+		return io_cqring_event_overflow(ctx, req->cqe.user_data,
+				req->cqe.res, req->cqe.flags,
+				extra1, extra2);
+	}
+}
+
+static noinline bool io_fill_cqe_aux(struct io_ring_ctx *ctx, u64 user_data,
+				     s32 res, u32 cflags)
+{
+	struct io_uring_cqe *cqe;
+
+	ctx->cq_extra++;
+	trace_io_uring_complete(ctx, NULL, user_data, res, cflags, 0, 0);
+
+	/*
+	 * If we can't get a cq entry, userspace overflowed the
+	 * submission (by quite a lot). Increment the overflow count in
+	 * the ring.
+	 */
+	cqe = io_get_cqe(ctx);
+	if (likely(cqe)) {
+		WRITE_ONCE(cqe->user_data, user_data);
+		WRITE_ONCE(cqe->res, res);
+		WRITE_ONCE(cqe->flags, cflags);
+
+		if (ctx->flags & IORING_SETUP_CQE32) {
+			WRITE_ONCE(cqe->big_cqe[0], 0);
+			WRITE_ONCE(cqe->big_cqe[1], 0);
+		}
+		return true;
+	}
+	return io_cqring_event_overflow(ctx, user_data, res, cflags, 0, 0);
+}
+
+static void __io_req_complete_put(struct io_kiocb *req)
+{
+	/*
+	 * If we're the last reference to this request, add to our locked
+	 * free_list cache.
+	 */
+	if (req_ref_put_and_test(req)) {
+		struct io_ring_ctx *ctx = req->ctx;
+
+		if (req->flags & IO_REQ_LINK_FLAGS) {
+			if (req->flags & IO_DISARM_MASK)
+				io_disarm_next(req);
+			if (req->link) {
+				io_req_task_queue(req->link);
+				req->link = NULL;
+			}
+		}
+		io_req_put_rsrc(req);
+		/*
+		 * Selected buffer deallocation in io_clean_op() assumes that
+		 * we don't hold ->completion_lock. Clean them here to avoid
+		 * deadlocks.
+		 */
+		io_put_kbuf_comp(req);
+		io_dismantle_req(req);
+		io_put_task(req->task, 1);
+		wq_list_add_head(&req->comp_list, &ctx->locked_free_list);
+		ctx->locked_free_nr++;
+	}
+}
+
+static void __io_req_complete_post(struct io_kiocb *req, s32 res,
+				   u32 cflags)
+{
+	if (!(req->flags & REQ_F_CQE_SKIP)) {
+		req->cqe.res = res;
+		req->cqe.flags = cflags;
+		__io_fill_cqe_req(req->ctx, req);
+	}
+	__io_req_complete_put(req);
+}
+
+static void io_req_complete_post(struct io_kiocb *req, s32 res, u32 cflags)
+{
+	struct io_ring_ctx *ctx = req->ctx;
+
+	spin_lock(&ctx->completion_lock);
+	__io_req_complete_post(req, res, cflags);
+	io_commit_cqring(ctx);
+	spin_unlock(&ctx->completion_lock);
+	io_cqring_ev_posted(ctx);
+}
+
+static inline void io_req_complete_state(struct io_kiocb *req, s32 res,
+					 u32 cflags)
+{
+	req->cqe.res = res;
+	req->cqe.flags = cflags;
+	req->flags |= REQ_F_COMPLETE_INLINE;
+}
+
+static inline void __io_req_complete(struct io_kiocb *req, unsigned issue_flags,
+				     s32 res, u32 cflags)
+{
+	if (issue_flags & IO_URING_F_COMPLETE_DEFER)
+		io_req_complete_state(req, res, cflags);
+	else
+		io_req_complete_post(req, res, cflags);
+}
+
+static inline void io_req_complete(struct io_kiocb *req, s32 res)
+{
+	if (res < 0)
+		req_set_fail(req);
+	__io_req_complete(req, 0, res, 0);
+}
+
+static void io_req_complete_failed(struct io_kiocb *req, s32 res)
+{
+	req_set_fail(req);
+	io_req_complete_post(req, res, io_put_kbuf(req, IO_URING_F_UNLOCKED));
+}
+
+/*
+ * Don't initialise the fields below on every allocation, but do that in
+ * advance and keep them valid across allocations.
+ */
+static void io_preinit_req(struct io_kiocb *req, struct io_ring_ctx *ctx)
+{
+	req->ctx = ctx;
+	req->link = NULL;
+	req->async_data = NULL;
+	/* not necessary, but safer to zero */
+	req->cqe.res = 0;
+}
+
+static void io_flush_cached_locked_reqs(struct io_ring_ctx *ctx,
+					struct io_submit_state *state)
+{
+	spin_lock(&ctx->completion_lock);
+	wq_list_splice(&ctx->locked_free_list, &state->free_list);
+	ctx->locked_free_nr = 0;
+	spin_unlock(&ctx->completion_lock);
+}
+
+static inline bool io_req_cache_empty(struct io_ring_ctx *ctx)
+{
+	return !ctx->submit_state.free_list.next;
+}
+
+/*
+ * A request might get retired back into the request caches even before opcode
+ * handlers and io_issue_sqe() are done with it, e.g. inline completion path.
+ * Because of that, io_alloc_req() should be called only under ->uring_lock
+ * and with extra caution to not get a request that is still worked on.
+ */
+static __cold bool __io_alloc_req_refill(struct io_ring_ctx *ctx)
+	__must_hold(&ctx->uring_lock)
+{
+	gfp_t gfp = GFP_KERNEL | __GFP_NOWARN;
+	void *reqs[IO_REQ_ALLOC_BATCH];
+	int ret, i;
+
+	/*
+	 * If we have more than a batch's worth of requests in our IRQ side
+	 * locked cache, grab the lock and move them over to our submission
+	 * side cache.
+	 */
+	if (data_race(ctx->locked_free_nr) > IO_COMPL_BATCH) {
+		io_flush_cached_locked_reqs(ctx, &ctx->submit_state);
+		if (!io_req_cache_empty(ctx))
+			return true;
+	}
+
+	ret = kmem_cache_alloc_bulk(req_cachep, gfp, ARRAY_SIZE(reqs), reqs);
+
+	/*
+	 * Bulk alloc is all-or-nothing. If we fail to get a batch,
+	 * retry single alloc to be on the safe side.
+	 */
+	if (unlikely(ret <= 0)) {
+		reqs[0] = kmem_cache_alloc(req_cachep, gfp);
+		if (!reqs[0])
+			return false;
+		ret = 1;
+	}
+
+	percpu_ref_get_many(&ctx->refs, ret);
+	for (i = 0; i < ret; i++) {
+		struct io_kiocb *req = reqs[i];
+
+		io_preinit_req(req, ctx);
+		io_req_add_to_cache(req, ctx);
+	}
+	return true;
+}
+
+static inline bool io_alloc_req_refill(struct io_ring_ctx *ctx)
+{
+	if (unlikely(io_req_cache_empty(ctx)))
+		return __io_alloc_req_refill(ctx);
+	return true;
+}
+
+static inline struct io_kiocb *io_alloc_req(struct io_ring_ctx *ctx)
+{
+	struct io_wq_work_node *node;
+
+	node = wq_stack_extract(&ctx->submit_state.free_list);
+	return container_of(node, struct io_kiocb, comp_list);
+}
+
+static inline void io_put_file(struct file *file)
+{
+	if (file)
+		fput(file);
+}
+
+static inline void io_dismantle_req(struct io_kiocb *req)
+{
+	unsigned int flags = req->flags;
+
+	if (unlikely(flags & IO_REQ_CLEAN_FLAGS))
+		io_clean_op(req);
+	if (!(flags & REQ_F_FIXED_FILE))
+		io_put_file(req->file);
+}
+
+static __cold void io_free_req(struct io_kiocb *req)
+{
+	struct io_ring_ctx *ctx = req->ctx;
+
+	io_req_put_rsrc(req);
+	io_dismantle_req(req);
+	io_put_task(req->task, 1);
+
+	spin_lock(&ctx->completion_lock);
+	wq_list_add_head(&req->comp_list, &ctx->locked_free_list);
+	ctx->locked_free_nr++;
+	spin_unlock(&ctx->completion_lock);
+}
+
+static inline void io_remove_next_linked(struct io_kiocb *req)
+{
+	struct io_kiocb *nxt = req->link;
+
+	req->link = nxt->link;
+	nxt->link = NULL;
+}
+
+static struct io_kiocb *io_disarm_linked_timeout(struct io_kiocb *req)
+	__must_hold(&req->ctx->completion_lock)
+	__must_hold(&req->ctx->timeout_lock)
+{
+	struct io_kiocb *link = req->link;
+
+	if (link && link->opcode == IORING_OP_LINK_TIMEOUT) {
+		struct io_timeout_data *io = link->async_data;
+
+		io_remove_next_linked(req);
+		link->timeout.head = NULL;
+		if (hrtimer_try_to_cancel(&io->timer) != -1) {
+			list_del(&link->timeout.list);
+			return link;
+		}
+	}
+	return NULL;
+}
+
+static void io_fail_links(struct io_kiocb *req)
+	__must_hold(&req->ctx->completion_lock)
+{
+	struct io_kiocb *nxt, *link = req->link;
+	bool ignore_cqes = req->flags & REQ_F_SKIP_LINK_CQES;
+
+	req->link = NULL;
+	while (link) {
+		long res = -ECANCELED;
+
+		if (link->flags & REQ_F_FAIL)
+			res = link->cqe.res;
+
+		nxt = link->link;
+		link->link = NULL;
+
+		trace_io_uring_fail_link(req->ctx, req, req->cqe.user_data,
+					req->opcode, link);
+
+		if (ignore_cqes)
+			link->flags |= REQ_F_CQE_SKIP;
+		else
+			link->flags &= ~REQ_F_CQE_SKIP;
+		__io_req_complete_post(link, res, 0);
+		link = nxt;
+	}
+}
+
+static bool io_disarm_next(struct io_kiocb *req)
+	__must_hold(&req->ctx->completion_lock)
+{
+	struct io_kiocb *link = NULL;
+	bool posted = false;
+
+	if (req->flags & REQ_F_ARM_LTIMEOUT) {
+		link = req->link;
+		req->flags &= ~REQ_F_ARM_LTIMEOUT;
+		if (link && link->opcode == IORING_OP_LINK_TIMEOUT) {
+			io_remove_next_linked(req);
+			io_req_tw_post_queue(link, -ECANCELED, 0);
+			posted = true;
+		}
+	} else if (req->flags & REQ_F_LINK_TIMEOUT) {
+		struct io_ring_ctx *ctx = req->ctx;
+
+		spin_lock_irq(&ctx->timeout_lock);
+		link = io_disarm_linked_timeout(req);
+		spin_unlock_irq(&ctx->timeout_lock);
+		if (link) {
+			posted = true;
+			io_req_tw_post_queue(link, -ECANCELED, 0);
+		}
+	}
+	if (unlikely((req->flags & REQ_F_FAIL) &&
+		     !(req->flags & REQ_F_HARDLINK))) {
+		posted |= (req->link != NULL);
+		io_fail_links(req);
+	}
+	return posted;
+}
+
+static void __io_req_find_next_prep(struct io_kiocb *req)
+{
+	struct io_ring_ctx *ctx = req->ctx;
+	bool posted;
+
+	spin_lock(&ctx->completion_lock);
+	posted = io_disarm_next(req);
+	io_commit_cqring(ctx);
+	spin_unlock(&ctx->completion_lock);
+	if (posted)
+		io_cqring_ev_posted(ctx);
+}
+
+static inline struct io_kiocb *io_req_find_next(struct io_kiocb *req)
+{
+	struct io_kiocb *nxt;
+
+	/*
+	 * If LINK is set, we have dependent requests in this chain. If we
+	 * didn't fail this request, queue the first one up, moving any other
+	 * dependencies to the next request. In case of failure, fail the rest
+	 * of the chain.
+	 */
+	if (unlikely(req->flags & IO_DISARM_MASK))
+		__io_req_find_next_prep(req);
+	nxt = req->link;
+	req->link = NULL;
+	return nxt;
+}
+
+static void ctx_flush_and_put(struct io_ring_ctx *ctx, bool *locked)
+{
+	if (!ctx)
+		return;
+	if (ctx->flags & IORING_SETUP_TASKRUN_FLAG)
+		atomic_andnot(IORING_SQ_TASKRUN, &ctx->rings->sq_flags);
+	if (*locked) {
+		io_submit_flush_completions(ctx);
+		mutex_unlock(&ctx->uring_lock);
+		*locked = false;
+	}
+	percpu_ref_put(&ctx->refs);
+}
+
+static inline void ctx_commit_and_unlock(struct io_ring_ctx *ctx)
+{
+	io_commit_cqring(ctx);
+	spin_unlock(&ctx->completion_lock);
+	io_cqring_ev_posted(ctx);
+}
+
+static void handle_prev_tw_list(struct io_wq_work_node *node,
+				struct io_ring_ctx **ctx, bool *uring_locked)
+{
+	if (*ctx && !*uring_locked)
+		spin_lock(&(*ctx)->completion_lock);
+
+	do {
+		struct io_wq_work_node *next = node->next;
+		struct io_kiocb *req = container_of(node, struct io_kiocb,
+						    io_task_work.node);
+
+		prefetch(container_of(next, struct io_kiocb, io_task_work.node));
+
+		if (req->ctx != *ctx) {
+			if (unlikely(!*uring_locked && *ctx))
+				ctx_commit_and_unlock(*ctx);
+
+			ctx_flush_and_put(*ctx, uring_locked);
+			*ctx = req->ctx;
+			/* if not contended, grab and improve batching */
+			*uring_locked = mutex_trylock(&(*ctx)->uring_lock);
+			percpu_ref_get(&(*ctx)->refs);
+			if (unlikely(!*uring_locked))
+				spin_lock(&(*ctx)->completion_lock);
+		}
+		if (likely(*uring_locked))
+			req->io_task_work.func(req, uring_locked);
+		else
+			__io_req_complete_post(req, req->cqe.res,
+						io_put_kbuf_comp(req));
+		node = next;
+	} while (node);
+
+	if (unlikely(!*uring_locked))
+		ctx_commit_and_unlock(*ctx);
+}
+
+static void handle_tw_list(struct io_wq_work_node *node,
+			   struct io_ring_ctx **ctx, bool *locked)
+{
+	do {
+		struct io_wq_work_node *next = node->next;
+		struct io_kiocb *req = container_of(node, struct io_kiocb,
+						    io_task_work.node);
+
+		prefetch(container_of(next, struct io_kiocb, io_task_work.node));
+
+		if (req->ctx != *ctx) {
+			ctx_flush_and_put(*ctx, locked);
+			*ctx = req->ctx;
+			/* if not contended, grab and improve batching */
+			*locked = mutex_trylock(&(*ctx)->uring_lock);
+			percpu_ref_get(&(*ctx)->refs);
+		}
+		req->io_task_work.func(req, locked);
+		node = next;
+	} while (node);
+}
+
+static void tctx_task_work(struct callback_head *cb)
+{
+	bool uring_locked = false;
+	struct io_ring_ctx *ctx = NULL;
+	struct io_uring_task *tctx = container_of(cb, struct io_uring_task,
+						  task_work);
+
+	while (1) {
+		struct io_wq_work_node *node1, *node2;
+
+		spin_lock_irq(&tctx->task_lock);
+		node1 = tctx->prio_task_list.first;
+		node2 = tctx->task_list.first;
+		INIT_WQ_LIST(&tctx->task_list);
+		INIT_WQ_LIST(&tctx->prio_task_list);
+		if (!node2 && !node1)
+			tctx->task_running = false;
+		spin_unlock_irq(&tctx->task_lock);
+		if (!node2 && !node1)
+			break;
+
+		if (node1)
+			handle_prev_tw_list(node1, &ctx, &uring_locked);
+		if (node2)
+			handle_tw_list(node2, &ctx, &uring_locked);
+		cond_resched();
+
+		if (data_race(!tctx->task_list.first) &&
+		    data_race(!tctx->prio_task_list.first) && uring_locked)
+			io_submit_flush_completions(ctx);
+	}
+
+	ctx_flush_and_put(ctx, &uring_locked);
+
+	/* relaxed read is enough as only the task itself sets ->in_idle */
+	if (unlikely(atomic_read(&tctx->in_idle)))
+		io_uring_drop_tctx_refs(current);
+}
+
+static void __io_req_task_work_add(struct io_kiocb *req,
+				   struct io_uring_task *tctx,
+				   struct io_wq_work_list *list)
+{
+	struct io_ring_ctx *ctx = req->ctx;
+	struct io_wq_work_node *node;
+	unsigned long flags;
+	bool running;
+
+	spin_lock_irqsave(&tctx->task_lock, flags);
+	wq_list_add_tail(&req->io_task_work.node, list);
+	running = tctx->task_running;
+	if (!running)
+		tctx->task_running = true;
+	spin_unlock_irqrestore(&tctx->task_lock, flags);
+
+	/* task_work already pending, we're done */
+	if (running)
+		return;
+
+	if (ctx->flags & IORING_SETUP_TASKRUN_FLAG)
+		atomic_or(IORING_SQ_TASKRUN, &ctx->rings->sq_flags);
+
+	if (likely(!task_work_add(req->task, &tctx->task_work, ctx->notify_method)))
+		return;
+
+	spin_lock_irqsave(&tctx->task_lock, flags);
+	tctx->task_running = false;
+	node = wq_list_merge(&tctx->prio_task_list, &tctx->task_list);
+	spin_unlock_irqrestore(&tctx->task_lock, flags);
+
+	while (node) {
+		req = container_of(node, struct io_kiocb, io_task_work.node);
+		node = node->next;
+		if (llist_add(&req->io_task_work.fallback_node,
+			      &req->ctx->fallback_llist))
+			schedule_delayed_work(&req->ctx->fallback_work, 1);
+	}
+}
+
+static void io_req_task_work_add(struct io_kiocb *req)
+{
+	struct io_uring_task *tctx = req->task->io_uring;
+
+	__io_req_task_work_add(req, tctx, &tctx->task_list);
+}
+
+static void io_req_task_prio_work_add(struct io_kiocb *req)
+{
+	struct io_uring_task *tctx = req->task->io_uring;
+
+	if (req->ctx->flags & IORING_SETUP_SQPOLL)
+		__io_req_task_work_add(req, tctx, &tctx->prio_task_list);
+	else
+		__io_req_task_work_add(req, tctx, &tctx->task_list);
+}
+
+static void io_req_tw_post(struct io_kiocb *req, bool *locked)
+{
+	io_req_complete_post(req, req->cqe.res, req->cqe.flags);
+}
+
+static void io_req_tw_post_queue(struct io_kiocb *req, s32 res, u32 cflags)
+{
+	req->cqe.res = res;
+	req->cqe.flags = cflags;
+	req->io_task_work.func = io_req_tw_post;
+	io_req_task_work_add(req);
+}
+
+static void io_req_task_cancel(struct io_kiocb *req, bool *locked)
+{
+	/* not needed for normal modes, but SQPOLL depends on it */
+	io_tw_lock(req->ctx, locked);
+	io_req_complete_failed(req, req->cqe.res);
+}
+
+static void io_req_task_submit(struct io_kiocb *req, bool *locked)
+{
+	io_tw_lock(req->ctx, locked);
+	/* req->task == current here, checking PF_EXITING is safe */
+	if (likely(!(req->task->flags & PF_EXITING)))
+		io_queue_sqe(req);
+	else
+		io_req_complete_failed(req, -EFAULT);
+}
+
+static void io_req_task_queue_fail(struct io_kiocb *req, int ret)
+{
+	req->cqe.res = ret;
+	req->io_task_work.func = io_req_task_cancel;
+	io_req_task_work_add(req);
+}
+
+static void io_req_task_queue(struct io_kiocb *req)
+{
+	req->io_task_work.func = io_req_task_submit;
+	io_req_task_work_add(req);
+}
+
+static void io_req_task_queue_reissue(struct io_kiocb *req)
+{
+	req->io_task_work.func = io_queue_iowq;
+	io_req_task_work_add(req);
+}
+
+static void io_queue_next(struct io_kiocb *req)
+{
+	struct io_kiocb *nxt = io_req_find_next(req);
+
+	if (nxt)
+		io_req_task_queue(nxt);
+}
+
+static void io_free_batch_list(struct io_ring_ctx *ctx,
+				struct io_wq_work_node *node)
+	__must_hold(&ctx->uring_lock)
+{
+	struct task_struct *task = NULL;
+	int task_refs = 0;
+
+	do {
+		struct io_kiocb *req = container_of(node, struct io_kiocb,
+						    comp_list);
+
+		if (unlikely(req->flags & IO_REQ_CLEAN_SLOW_FLAGS)) {
+			if (req->flags & REQ_F_REFCOUNT) {
+				node = req->comp_list.next;
+				if (!req_ref_put_and_test(req))
+					continue;
+			}
+			if ((req->flags & REQ_F_POLLED) && req->apoll) {
+				struct async_poll *apoll = req->apoll;
+
+				if (apoll->double_poll)
+					kfree(apoll->double_poll);
+				list_add(&apoll->poll.wait.entry,
+						&ctx->apoll_cache);
+				req->flags &= ~REQ_F_POLLED;
+			}
+			if (req->flags & IO_REQ_LINK_FLAGS)
+				io_queue_next(req);
+			if (unlikely(req->flags & IO_REQ_CLEAN_FLAGS))
+				io_clean_op(req);
+		}
+		if (!(req->flags & REQ_F_FIXED_FILE))
+			io_put_file(req->file);
+
+		io_req_put_rsrc_locked(req, ctx);
+
+		if (req->task != task) {
+			if (task)
+				io_put_task(task, task_refs);
+			task = req->task;
+			task_refs = 0;
+		}
+		task_refs++;
+		node = req->comp_list.next;
+		io_req_add_to_cache(req, ctx);
+	} while (node);
+
+	if (task)
+		io_put_task(task, task_refs);
+}
+
+static void __io_submit_flush_completions(struct io_ring_ctx *ctx)
+	__must_hold(&ctx->uring_lock)
+{
+	struct io_wq_work_node *node, *prev;
+	struct io_submit_state *state = &ctx->submit_state;
+
+	if (state->flush_cqes) {
+		spin_lock(&ctx->completion_lock);
+		wq_list_for_each(node, prev, &state->compl_reqs) {
+			struct io_kiocb *req = container_of(node, struct io_kiocb,
+						    comp_list);
+
+			if (!(req->flags & REQ_F_CQE_SKIP))
+				__io_fill_cqe_req(ctx, req);
+		}
+
+		io_commit_cqring(ctx);
+		spin_unlock(&ctx->completion_lock);
+		io_cqring_ev_posted(ctx);
+		state->flush_cqes = false;
+	}
+
+	io_free_batch_list(ctx, state->compl_reqs.first);
+	INIT_WQ_LIST(&state->compl_reqs);
+}
+
+/*
+ * Drop reference to request, return next in chain (if there is one) if this
+ * was the last reference to this request.
+ */
+static inline struct io_kiocb *io_put_req_find_next(struct io_kiocb *req)
+{
+	struct io_kiocb *nxt = NULL;
+
+	if (req_ref_put_and_test(req)) {
+		if (unlikely(req->flags & IO_REQ_LINK_FLAGS))
+			nxt = io_req_find_next(req);
+		io_free_req(req);
+	}
+	return nxt;
+}
+
+static inline void io_put_req(struct io_kiocb *req)
+{
+	if (req_ref_put_and_test(req)) {
+		io_queue_next(req);
+		io_free_req(req);
+	}
+}
+
+static unsigned io_cqring_events(struct io_ring_ctx *ctx)
+{
+	/* See comment at the top of this file */
+	smp_rmb();
+	return __io_cqring_events(ctx);
+}
+
+static inline unsigned int io_sqring_entries(struct io_ring_ctx *ctx)
+{
+	struct io_rings *rings = ctx->rings;
+
+	/* make sure SQ entry isn't read before tail */
+	return smp_load_acquire(&rings->sq.tail) - ctx->cached_sq_head;
+}
+
+static inline bool io_run_task_work(void)
+{
+	if (test_thread_flag(TIF_NOTIFY_SIGNAL) || task_work_pending(current)) {
+		__set_current_state(TASK_RUNNING);
+		clear_notify_signal();
+		if (task_work_pending(current))
+			task_work_run();
+		return true;
+	}
+
+	return false;
+}
+
+static int io_do_iopoll(struct io_ring_ctx *ctx, bool force_nonspin)
+{
+	struct io_wq_work_node *pos, *start, *prev;
+	unsigned int poll_flags = BLK_POLL_NOSLEEP;
+	DEFINE_IO_COMP_BATCH(iob);
+	int nr_events = 0;
+
+	/*
+	 * Only spin for completions if we don't have multiple devices hanging
+	 * off our complete list.
+	 */
+	if (ctx->poll_multi_queue || force_nonspin)
+		poll_flags |= BLK_POLL_ONESHOT;
+
+	wq_list_for_each(pos, start, &ctx->iopoll_list) {
+		struct io_kiocb *req = container_of(pos, struct io_kiocb, comp_list);
+		struct kiocb *kiocb = &req->rw.kiocb;
+		int ret;
+
+		/*
+		 * Move completed and retryable entries to our local lists.
+		 * If we find a request that requires polling, break out
+		 * and complete those lists first, if we have entries there.
+		 */
+		if (READ_ONCE(req->iopoll_completed))
+			break;
+
+		ret = kiocb->ki_filp->f_op->iopoll(kiocb, &iob, poll_flags);
+		if (unlikely(ret < 0))
+			return ret;
+		else if (ret)
+			poll_flags |= BLK_POLL_ONESHOT;
+
+		/* iopoll may have completed current req */
+		if (!rq_list_empty(iob.req_list) ||
+		    READ_ONCE(req->iopoll_completed))
+			break;
+	}
+
+	if (!rq_list_empty(iob.req_list))
+		iob.complete(&iob);
+	else if (!pos)
+		return 0;
+
+	prev = start;
+	wq_list_for_each_resume(pos, prev) {
+		struct io_kiocb *req = container_of(pos, struct io_kiocb, comp_list);
+
+		/* order with io_complete_rw_iopoll(), e.g. ->result updates */
+		if (!smp_load_acquire(&req->iopoll_completed))
+			break;
+		nr_events++;
+		if (unlikely(req->flags & REQ_F_CQE_SKIP))
+			continue;
+
+		req->cqe.flags = io_put_kbuf(req, 0);
+		__io_fill_cqe_req(req->ctx, req);
+	}
+
+	if (unlikely(!nr_events))
+		return 0;
+
+	io_commit_cqring(ctx);
+	io_cqring_ev_posted_iopoll(ctx);
+	pos = start ? start->next : ctx->iopoll_list.first;
+	wq_list_cut(&ctx->iopoll_list, prev, start);
+	io_free_batch_list(ctx, pos);
+	return nr_events;
+}
+
+/*
+ * We can't just wait for polled events to come to us, we have to actively
+ * find and complete them.
+ */
+static __cold void io_iopoll_try_reap_events(struct io_ring_ctx *ctx)
+{
+	if (!(ctx->flags & IORING_SETUP_IOPOLL))
+		return;
+
+	mutex_lock(&ctx->uring_lock);
+	while (!wq_list_empty(&ctx->iopoll_list)) {
+		/* let it sleep and repeat later if can't complete a request */
+		if (io_do_iopoll(ctx, true) == 0)
+			break;
+		/*
+		 * Ensure we allow local-to-the-cpu processing to take place,
+		 * in this case we need to ensure that we reap all events.
+		 * Also let task_work, etc. to progress by releasing the mutex
+		 */
+		if (need_resched()) {
+			mutex_unlock(&ctx->uring_lock);
+			cond_resched();
+			mutex_lock(&ctx->uring_lock);
+		}
+	}
+	mutex_unlock(&ctx->uring_lock);
+}
+
+static int io_iopoll_check(struct io_ring_ctx *ctx, long min)
+{
+	unsigned int nr_events = 0;
+	int ret = 0;
+	unsigned long check_cq;
+
+	/*
+	 * Don't enter poll loop if we already have events pending.
+	 * If we do, we can potentially be spinning for commands that
+	 * already triggered a CQE (eg in error).
+	 */
+	check_cq = READ_ONCE(ctx->check_cq);
+	if (check_cq & BIT(IO_CHECK_CQ_OVERFLOW_BIT))
+		__io_cqring_overflow_flush(ctx, false);
+	if (io_cqring_events(ctx))
+		return 0;
+
+	/*
+	 * Similarly do not spin if we have not informed the user of any
+	 * dropped CQE.
+	 */
+	if (unlikely(check_cq & BIT(IO_CHECK_CQ_DROPPED_BIT)))
+		return -EBADR;
+
+	do {
+		/*
+		 * If a submit got punted to a workqueue, we can have the
+		 * application entering polling for a command before it gets
+		 * issued. That app will hold the uring_lock for the duration
+		 * of the poll right here, so we need to take a breather every
+		 * now and then to ensure that the issue has a chance to add
+		 * the poll to the issued list. Otherwise we can spin here
+		 * forever, while the workqueue is stuck trying to acquire the
+		 * very same mutex.
+		 */
+		if (wq_list_empty(&ctx->iopoll_list)) {
+			u32 tail = ctx->cached_cq_tail;
+
+			mutex_unlock(&ctx->uring_lock);
+			io_run_task_work();
+			mutex_lock(&ctx->uring_lock);
+
+			/* some requests don't go through iopoll_list */
+			if (tail != ctx->cached_cq_tail ||
+			    wq_list_empty(&ctx->iopoll_list))
+				break;
+		}
+		ret = io_do_iopoll(ctx, !min);
+		if (ret < 0)
+			break;
+		nr_events += ret;
+		ret = 0;
+	} while (nr_events < min && !need_resched());
+
+	return ret;
+}
+
+static void kiocb_end_write(struct io_kiocb *req)
+{
+	/*
+	 * Tell lockdep we inherited freeze protection from submission
+	 * thread.
+	 */
+	if (req->flags & REQ_F_ISREG) {
+		struct super_block *sb = file_inode(req->file)->i_sb;
+
+		__sb_writers_acquired(sb, SB_FREEZE_WRITE);
+		sb_end_write(sb);
+	}
+}
+
+#ifdef CONFIG_BLOCK
+static bool io_resubmit_prep(struct io_kiocb *req)
+{
+	struct io_async_rw *rw = req->async_data;
+
+	if (!req_has_async_data(req))
+		return !io_req_prep_async(req);
+	iov_iter_restore(&rw->s.iter, &rw->s.iter_state);
+	return true;
+}
+
+static bool io_rw_should_reissue(struct io_kiocb *req)
+{
+	umode_t mode = file_inode(req->file)->i_mode;
+	struct io_ring_ctx *ctx = req->ctx;
+
+	if (!S_ISBLK(mode) && !S_ISREG(mode))
+		return false;
+	if ((req->flags & REQ_F_NOWAIT) || (io_wq_current_is_worker() &&
+	    !(ctx->flags & IORING_SETUP_IOPOLL)))
+		return false;
+	/*
+	 * If ref is dying, we might be running poll reap from the exit work.
+	 * Don't attempt to reissue from that path, just let it fail with
+	 * -EAGAIN.
+	 */
+	if (percpu_ref_is_dying(&ctx->refs))
+		return false;
+	/*
+	 * Play it safe and assume not safe to re-import and reissue if we're
+	 * not in the original thread group (or in task context).
+	 */
+	if (!same_thread_group(req->task, current) || !in_task())
+		return false;
+	return true;
+}
+#else
+static bool io_resubmit_prep(struct io_kiocb *req)
+{
+	return false;
+}
+static bool io_rw_should_reissue(struct io_kiocb *req)
+{
+	return false;
+}
+#endif
+
+static bool __io_complete_rw_common(struct io_kiocb *req, long res)
+{
+	if (req->rw.kiocb.ki_flags & IOCB_WRITE) {
+		kiocb_end_write(req);
+		fsnotify_modify(req->file);
+	} else {
+		fsnotify_access(req->file);
+	}
+	if (unlikely(res != req->cqe.res)) {
+		if ((res == -EAGAIN || res == -EOPNOTSUPP) &&
+		    io_rw_should_reissue(req)) {
+			req->flags |= REQ_F_REISSUE | REQ_F_PARTIAL_IO;
+			return true;
+		}
+		req_set_fail(req);
+		req->cqe.res = res;
+	}
+	return false;
+}
+
+static inline void io_req_task_complete(struct io_kiocb *req, bool *locked)
+{
+	int res = req->cqe.res;
+
+	if (*locked) {
+		io_req_complete_state(req, res, io_put_kbuf(req, 0));
+		io_req_add_compl_list(req);
+	} else {
+		io_req_complete_post(req, res,
+					io_put_kbuf(req, IO_URING_F_UNLOCKED));
+	}
+}
+
+static void __io_complete_rw(struct io_kiocb *req, long res,
+			     unsigned int issue_flags)
+{
+	if (__io_complete_rw_common(req, res))
+		return;
+	__io_req_complete(req, issue_flags, req->cqe.res,
+				io_put_kbuf(req, issue_flags));
+}
+
+static void io_complete_rw(struct kiocb *kiocb, long res)
+{
+	struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw.kiocb);
+
+	if (__io_complete_rw_common(req, res))
+		return;
+	req->cqe.res = res;
+	req->io_task_work.func = io_req_task_complete;
+	io_req_task_prio_work_add(req);
+}
+
+static void io_complete_rw_iopoll(struct kiocb *kiocb, long res)
+{
+	struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw.kiocb);
+
+	if (kiocb->ki_flags & IOCB_WRITE)
+		kiocb_end_write(req);
+	if (unlikely(res != req->cqe.res)) {
+		if (res == -EAGAIN && io_rw_should_reissue(req)) {
+			req->flags |= REQ_F_REISSUE | REQ_F_PARTIAL_IO;
+			return;
+		}
+		req->cqe.res = res;
+	}
+
+	/* order with io_iopoll_complete() checking ->iopoll_completed */
+	smp_store_release(&req->iopoll_completed, 1);
+}
+
+/*
+ * After the iocb has been issued, it's safe to be found on the poll list.
+ * Adding the kiocb to the list AFTER submission ensures that we don't
+ * find it from a io_do_iopoll() thread before the issuer is done
+ * accessing the kiocb cookie.
+ */
+static void io_iopoll_req_issued(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_ring_ctx *ctx = req->ctx;
+	const bool needs_lock = issue_flags & IO_URING_F_UNLOCKED;
+
+	/* workqueue context doesn't hold uring_lock, grab it now */
+	if (unlikely(needs_lock))
+		mutex_lock(&ctx->uring_lock);
+
+	/*
+	 * Track whether we have multiple files in our lists. This will impact
+	 * how we do polling eventually, not spinning if we're on potentially
+	 * different devices.
+	 */
+	if (wq_list_empty(&ctx->iopoll_list)) {
+		ctx->poll_multi_queue = false;
+	} else if (!ctx->poll_multi_queue) {
+		struct io_kiocb *list_req;
+
+		list_req = container_of(ctx->iopoll_list.first, struct io_kiocb,
+					comp_list);
+		if (list_req->file != req->file)
+			ctx->poll_multi_queue = true;
+	}
+
+	/*
+	 * For fast devices, IO may have already completed. If it has, add
+	 * it to the front so we find it first.
+	 */
+	if (READ_ONCE(req->iopoll_completed))
+		wq_list_add_head(&req->comp_list, &ctx->iopoll_list);
+	else
+		wq_list_add_tail(&req->comp_list, &ctx->iopoll_list);
+
+	if (unlikely(needs_lock)) {
+		/*
+		 * If IORING_SETUP_SQPOLL is enabled, sqes are either handle
+		 * in sq thread task context or in io worker task context. If
+		 * current task context is sq thread, we don't need to check
+		 * whether should wake up sq thread.
+		 */
+		if ((ctx->flags & IORING_SETUP_SQPOLL) &&
+		    wq_has_sleeper(&ctx->sq_data->wait))
+			wake_up(&ctx->sq_data->wait);
+
+		mutex_unlock(&ctx->uring_lock);
+	}
+}
+
+static bool io_bdev_nowait(struct block_device *bdev)
+{
+	return !bdev || blk_queue_nowait(bdev_get_queue(bdev));
+}
+
+/*
+ * If we tracked the file through the SCM inflight mechanism, we could support
+ * any file. For now, just ensure that anything potentially problematic is done
+ * inline.
+ */
+static bool __io_file_supports_nowait(struct file *file, umode_t mode)
+{
+	if (S_ISBLK(mode)) {
+		if (IS_ENABLED(CONFIG_BLOCK) &&
+		    io_bdev_nowait(I_BDEV(file->f_mapping->host)))
+			return true;
+		return false;
+	}
+	if (S_ISSOCK(mode))
+		return true;
+	if (S_ISREG(mode)) {
+		if (IS_ENABLED(CONFIG_BLOCK) &&
+		    io_bdev_nowait(file->f_inode->i_sb->s_bdev) &&
+		    file->f_op != &io_uring_fops)
+			return true;
+		return false;
+	}
+
+	/* any ->read/write should understand O_NONBLOCK */
+	if (file->f_flags & O_NONBLOCK)
+		return true;
+	return file->f_mode & FMODE_NOWAIT;
+}
+
+/*
+ * If we tracked the file through the SCM inflight mechanism, we could support
+ * any file. For now, just ensure that anything potentially problematic is done
+ * inline.
+ */
+static unsigned int io_file_get_flags(struct file *file)
+{
+	umode_t mode = file_inode(file)->i_mode;
+	unsigned int res = 0;
+
+	if (S_ISREG(mode))
+		res |= FFS_ISREG;
+	if (__io_file_supports_nowait(file, mode))
+		res |= FFS_NOWAIT;
+	if (io_file_need_scm(file))
+		res |= FFS_SCM;
+	return res;
+}
+
+static inline bool io_file_supports_nowait(struct io_kiocb *req)
+{
+	return req->flags & REQ_F_SUPPORT_NOWAIT;
+}
+
+static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+	struct kiocb *kiocb = &req->rw.kiocb;
+	unsigned ioprio;
+	int ret;
+
+	kiocb->ki_pos = READ_ONCE(sqe->off);
+	/* used for fixed read/write too - just read unconditionally */
+	req->buf_index = READ_ONCE(sqe->buf_index);
+
+	if (req->opcode == IORING_OP_READ_FIXED ||
+	    req->opcode == IORING_OP_WRITE_FIXED) {
+		struct io_ring_ctx *ctx = req->ctx;
+		u16 index;
+
+		if (unlikely(req->buf_index >= ctx->nr_user_bufs))
+			return -EFAULT;
+		index = array_index_nospec(req->buf_index, ctx->nr_user_bufs);
+		req->imu = ctx->user_bufs[index];
+		io_req_set_rsrc_node(req, ctx, 0);
+	}
+
+	ioprio = READ_ONCE(sqe->ioprio);
+	if (ioprio) {
+		ret = ioprio_check_cap(ioprio);
+		if (ret)
+			return ret;
+
+		kiocb->ki_ioprio = ioprio;
+	} else {
+		kiocb->ki_ioprio = get_current_ioprio();
+	}
+
+	req->rw.addr = READ_ONCE(sqe->addr);
+	req->rw.len = READ_ONCE(sqe->len);
+	req->rw.flags = READ_ONCE(sqe->rw_flags);
+	return 0;
+}
+
+static inline void io_rw_done(struct kiocb *kiocb, ssize_t ret)
+{
+	switch (ret) {
+	case -EIOCBQUEUED:
+		break;
+	case -ERESTARTSYS:
+	case -ERESTARTNOINTR:
+	case -ERESTARTNOHAND:
+	case -ERESTART_RESTARTBLOCK:
+		/*
+		 * We can't just restart the syscall, since previously
+		 * submitted sqes may already be in progress. Just fail this
+		 * IO with EINTR.
+		 */
+		ret = -EINTR;
+		fallthrough;
+	default:
+		kiocb->ki_complete(kiocb, ret);
+	}
+}
+
+static inline loff_t *io_kiocb_update_pos(struct io_kiocb *req)
+{
+	struct kiocb *kiocb = &req->rw.kiocb;
+
+	if (kiocb->ki_pos != -1)
+		return &kiocb->ki_pos;
+
+	if (!(req->file->f_mode & FMODE_STREAM)) {
+		req->flags |= REQ_F_CUR_POS;
+		kiocb->ki_pos = req->file->f_pos;
+		return &kiocb->ki_pos;
+	}
+
+	kiocb->ki_pos = 0;
+	return NULL;
+}
+
+static void kiocb_done(struct io_kiocb *req, ssize_t ret,
+		       unsigned int issue_flags)
+{
+	struct io_async_rw *io = req->async_data;
+
+	/* add previously done IO, if any */
+	if (req_has_async_data(req) && io->bytes_done > 0) {
+		if (ret < 0)
+			ret = io->bytes_done;
+		else
+			ret += io->bytes_done;
+	}
+
+	if (req->flags & REQ_F_CUR_POS)
+		req->file->f_pos = req->rw.kiocb.ki_pos;
+	if (ret >= 0 && (req->rw.kiocb.ki_complete == io_complete_rw))
+		__io_complete_rw(req, ret, issue_flags);
+	else
+		io_rw_done(&req->rw.kiocb, ret);
+
+	if (req->flags & REQ_F_REISSUE) {
+		req->flags &= ~REQ_F_REISSUE;
+		if (io_resubmit_prep(req))
+			io_req_task_queue_reissue(req);
+		else
+			io_req_task_queue_fail(req, ret);
+	}
+}
+
+static int __io_import_fixed(struct io_kiocb *req, int rw, struct iov_iter *iter,
+			     struct io_mapped_ubuf *imu)
+{
+	size_t len = req->rw.len;
+	u64 buf_end, buf_addr = req->rw.addr;
+	size_t offset;
+
+	if (unlikely(check_add_overflow(buf_addr, (u64)len, &buf_end)))
+		return -EFAULT;
+	/* not inside the mapped region */
+	if (unlikely(buf_addr < imu->ubuf || buf_end > imu->ubuf_end))
+		return -EFAULT;
+
+	/*
+	 * May not be a start of buffer, set size appropriately
+	 * and advance us to the beginning.
+	 */
+	offset = buf_addr - imu->ubuf;
+	iov_iter_bvec(iter, rw, imu->bvec, imu->nr_bvecs, offset + len);
+
+	if (offset) {
+		/*
+		 * Don't use iov_iter_advance() here, as it's really slow for
+		 * using the latter parts of a big fixed buffer - it iterates
+		 * over each segment manually. We can cheat a bit here, because
+		 * we know that:
+		 *
+		 * 1) it's a BVEC iter, we set it up
+		 * 2) all bvecs are PAGE_SIZE in size, except potentially the
+		 *    first and last bvec
+		 *
+		 * So just find our index, and adjust the iterator afterwards.
+		 * If the offset is within the first bvec (or the whole first
+		 * bvec, just use iov_iter_advance(). This makes it easier
+		 * since we can just skip the first segment, which may not
+		 * be PAGE_SIZE aligned.
+		 */
+		const struct bio_vec *bvec = imu->bvec;
+
+		if (offset <= bvec->bv_len) {
+			iov_iter_advance(iter, offset);
+		} else {
+			unsigned long seg_skip;
+
+			/* skip first vec */
+			offset -= bvec->bv_len;
+			seg_skip = 1 + (offset >> PAGE_SHIFT);
+
+			iter->bvec = bvec + seg_skip;
+			iter->nr_segs -= seg_skip;
+			iter->count -= bvec->bv_len + offset;
+			iter->iov_offset = offset & ~PAGE_MASK;
+		}
+	}
+
+	return 0;
+}
+
+static int io_import_fixed(struct io_kiocb *req, int rw, struct iov_iter *iter,
+			   unsigned int issue_flags)
+{
+	if (WARN_ON_ONCE(!req->imu))
+		return -EFAULT;
+	return __io_import_fixed(req, rw, iter, req->imu);
+}
+
+static int io_buffer_add_list(struct io_ring_ctx *ctx,
+			      struct io_buffer_list *bl, unsigned int bgid)
+{
+	bl->bgid = bgid;
+	if (bgid < BGID_ARRAY)
+		return 0;
+
+	return xa_err(xa_store(&ctx->io_bl_xa, bgid, bl, GFP_KERNEL));
+}
+
+static void __user *io_provided_buffer_select(struct io_kiocb *req, size_t *len,
+					      struct io_buffer_list *bl)
+{
+	if (!list_empty(&bl->buf_list)) {
+		struct io_buffer *kbuf;
+
+		kbuf = list_first_entry(&bl->buf_list, struct io_buffer, list);
+		list_del(&kbuf->list);
+		if (*len > kbuf->len)
+			*len = kbuf->len;
+		req->flags |= REQ_F_BUFFER_SELECTED;
+		req->kbuf = kbuf;
+		req->buf_index = kbuf->bid;
+		return u64_to_user_ptr(kbuf->addr);
+	}
+	return NULL;
+}
+
+static void __user *io_ring_buffer_select(struct io_kiocb *req, size_t *len,
+					  struct io_buffer_list *bl,
+					  unsigned int issue_flags)
+{
+	struct io_uring_buf_ring *br = bl->buf_ring;
+	struct io_uring_buf *buf;
+	__u16 head = bl->head;
+
+	if (unlikely(smp_load_acquire(&br->tail) == head))
+		return NULL;
+
+	head &= bl->mask;
+	if (head < IO_BUFFER_LIST_BUF_PER_PAGE) {
+		buf = &br->bufs[head];
+	} else {
+		int off = head & (IO_BUFFER_LIST_BUF_PER_PAGE - 1);
+		int index = head / IO_BUFFER_LIST_BUF_PER_PAGE;
+		buf = page_address(bl->buf_pages[index]);
+		buf += off;
+	}
+	if (*len > buf->len)
+		*len = buf->len;
+	req->flags |= REQ_F_BUFFER_RING;
+	req->buf_list = bl;
+	req->buf_index = buf->bid;
+
+	if (issue_flags & IO_URING_F_UNLOCKED || !file_can_poll(req->file)) {
+		/*
+		 * If we came in unlocked, we have no choice but to consume the
+		 * buffer here. This does mean it'll be pinned until the IO
+		 * completes. But coming in unlocked means we're in io-wq
+		 * context, hence there should be no further retry. For the
+		 * locked case, the caller must ensure to call the commit when
+		 * the transfer completes (or if we get -EAGAIN and must poll
+		 * or retry).
+		 */
+		req->buf_list = NULL;
+		bl->head++;
+	}
+	return u64_to_user_ptr(buf->addr);
+}
+
+static void __user *io_buffer_select(struct io_kiocb *req, size_t *len,
+				     unsigned int issue_flags)
+{
+	struct io_ring_ctx *ctx = req->ctx;
+	struct io_buffer_list *bl;
+	void __user *ret = NULL;
+
+	io_ring_submit_lock(req->ctx, issue_flags);
+
+	bl = io_buffer_get_list(ctx, req->buf_index);
+	if (likely(bl)) {
+		if (bl->buf_nr_pages)
+			ret = io_ring_buffer_select(req, len, bl, issue_flags);
+		else
+			ret = io_provided_buffer_select(req, len, bl);
+	}
+	io_ring_submit_unlock(req->ctx, issue_flags);
+	return ret;
+}
+
+#ifdef CONFIG_COMPAT
+static ssize_t io_compat_import(struct io_kiocb *req, struct iovec *iov,
+				unsigned int issue_flags)
+{
+	struct compat_iovec __user *uiov;
+	compat_ssize_t clen;
+	void __user *buf;
+	size_t len;
+
+	uiov = u64_to_user_ptr(req->rw.addr);
+	if (!access_ok(uiov, sizeof(*uiov)))
+		return -EFAULT;
+	if (__get_user(clen, &uiov->iov_len))
+		return -EFAULT;
+	if (clen < 0)
+		return -EINVAL;
+
+	len = clen;
+	buf = io_buffer_select(req, &len, issue_flags);
+	if (!buf)
+		return -ENOBUFS;
+	req->rw.addr = (unsigned long) buf;
+	iov[0].iov_base = buf;
+	req->rw.len = iov[0].iov_len = (compat_size_t) len;
+	return 0;
+}
+#endif
+
+static ssize_t __io_iov_buffer_select(struct io_kiocb *req, struct iovec *iov,
+				      unsigned int issue_flags)
+{
+	struct iovec __user *uiov = u64_to_user_ptr(req->rw.addr);
+	void __user *buf;
+	ssize_t len;
+
+	if (copy_from_user(iov, uiov, sizeof(*uiov)))
+		return -EFAULT;
+
+	len = iov[0].iov_len;
+	if (len < 0)
+		return -EINVAL;
+	buf = io_buffer_select(req, &len, issue_flags);
+	if (!buf)
+		return -ENOBUFS;
+	req->rw.addr = (unsigned long) buf;
+	iov[0].iov_base = buf;
+	req->rw.len = iov[0].iov_len = len;
+	return 0;
+}
+
+static ssize_t io_iov_buffer_select(struct io_kiocb *req, struct iovec *iov,
+				    unsigned int issue_flags)
+{
+	if (req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING)) {
+		iov[0].iov_base = u64_to_user_ptr(req->rw.addr);
+		iov[0].iov_len = req->rw.len;
+		return 0;
+	}
+	if (req->rw.len != 1)
+		return -EINVAL;
+
+#ifdef CONFIG_COMPAT
+	if (req->ctx->compat)
+		return io_compat_import(req, iov, issue_flags);
+#endif
+
+	return __io_iov_buffer_select(req, iov, issue_flags);
+}
+
+static inline bool io_do_buffer_select(struct io_kiocb *req)
+{
+	if (!(req->flags & REQ_F_BUFFER_SELECT))
+		return false;
+	return !(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING));
+}
+
+static struct iovec *__io_import_iovec(int rw, struct io_kiocb *req,
+				       struct io_rw_state *s,
+				       unsigned int issue_flags)
+{
+	struct iov_iter *iter = &s->iter;
+	u8 opcode = req->opcode;
+	struct iovec *iovec;
+	void __user *buf;
+	size_t sqe_len;
+	ssize_t ret;
+
+	if (opcode == IORING_OP_READ_FIXED || opcode == IORING_OP_WRITE_FIXED) {
+		ret = io_import_fixed(req, rw, iter, issue_flags);
+		if (ret)
+			return ERR_PTR(ret);
+		return NULL;
+	}
+
+	buf = u64_to_user_ptr(req->rw.addr);
+	sqe_len = req->rw.len;
+
+	if (opcode == IORING_OP_READ || opcode == IORING_OP_WRITE) {
+		if (io_do_buffer_select(req)) {
+			buf = io_buffer_select(req, &sqe_len, issue_flags);
+			if (!buf)
+				return ERR_PTR(-ENOBUFS);
+			req->rw.addr = (unsigned long) buf;
+			req->rw.len = sqe_len;
+		}
+
+		ret = import_single_range(rw, buf, sqe_len, s->fast_iov, iter);
+		if (ret)
+			return ERR_PTR(ret);
+		return NULL;
+	}
+
+	iovec = s->fast_iov;
+	if (req->flags & REQ_F_BUFFER_SELECT) {
+		ret = io_iov_buffer_select(req, iovec, issue_flags);
+		if (ret)
+			return ERR_PTR(ret);
+		iov_iter_init(iter, rw, iovec, 1, iovec->iov_len);
+		return NULL;
+	}
+
+	ret = __import_iovec(rw, buf, sqe_len, UIO_FASTIOV, &iovec, iter,
+			      req->ctx->compat);
+	if (unlikely(ret < 0))
+		return ERR_PTR(ret);
+	return iovec;
+}
+
+static inline int io_import_iovec(int rw, struct io_kiocb *req,
+				  struct iovec **iovec, struct io_rw_state *s,
+				  unsigned int issue_flags)
+{
+	*iovec = __io_import_iovec(rw, req, s, issue_flags);
+	if (unlikely(IS_ERR(*iovec)))
+		return PTR_ERR(*iovec);
+
+	iov_iter_save_state(&s->iter, &s->iter_state);
+	return 0;
+}
+
+static inline loff_t *io_kiocb_ppos(struct kiocb *kiocb)
+{
+	return (kiocb->ki_filp->f_mode & FMODE_STREAM) ? NULL : &kiocb->ki_pos;
+}
+
+/*
+ * For files that don't have ->read_iter() and ->write_iter(), handle them
+ * by looping over ->read() or ->write() manually.
+ */
+static ssize_t loop_rw_iter(int rw, struct io_kiocb *req, struct iov_iter *iter)
+{
+	struct kiocb *kiocb = &req->rw.kiocb;
+	struct file *file = req->file;
+	ssize_t ret = 0;
+	loff_t *ppos;
+
+	/*
+	 * Don't support polled IO through this interface, and we can't
+	 * support non-blocking either. For the latter, this just causes
+	 * the kiocb to be handled from an async context.
+	 */
+	if (kiocb->ki_flags & IOCB_HIPRI)
+		return -EOPNOTSUPP;
+	if ((kiocb->ki_flags & IOCB_NOWAIT) &&
+	    !(kiocb->ki_filp->f_flags & O_NONBLOCK))
+		return -EAGAIN;
+
+	ppos = io_kiocb_ppos(kiocb);
+
+	while (iov_iter_count(iter)) {
+		struct iovec iovec;
+		ssize_t nr;
+
+		if (!iov_iter_is_bvec(iter)) {
+			iovec = iov_iter_iovec(iter);
+		} else {
+			iovec.iov_base = u64_to_user_ptr(req->rw.addr);
+			iovec.iov_len = req->rw.len;
+		}
+
+		if (rw == READ) {
+			nr = file->f_op->read(file, iovec.iov_base,
+					      iovec.iov_len, ppos);
+		} else {
+			nr = file->f_op->write(file, iovec.iov_base,
+					       iovec.iov_len, ppos);
+		}
+
+		if (nr < 0) {
+			if (!ret)
+				ret = nr;
+			break;
+		}
+		ret += nr;
+		if (!iov_iter_is_bvec(iter)) {
+			iov_iter_advance(iter, nr);
+		} else {
+			req->rw.addr += nr;
+			req->rw.len -= nr;
+			if (!req->rw.len)
+				break;
+		}
+		if (nr != iovec.iov_len)
+			break;
+	}
+
+	return ret;
+}
+
+static void io_req_map_rw(struct io_kiocb *req, const struct iovec *iovec,
+			  const struct iovec *fast_iov, struct iov_iter *iter)
+{
+	struct io_async_rw *rw = req->async_data;
+
+	memcpy(&rw->s.iter, iter, sizeof(*iter));
+	rw->free_iovec = iovec;
+	rw->bytes_done = 0;
+	/* can only be fixed buffers, no need to do anything */
+	if (iov_iter_is_bvec(iter))
+		return;
+	if (!iovec) {
+		unsigned iov_off = 0;
+
+		rw->s.iter.iov = rw->s.fast_iov;
+		if (iter->iov != fast_iov) {
+			iov_off = iter->iov - fast_iov;
+			rw->s.iter.iov += iov_off;
+		}
+		if (rw->s.fast_iov != fast_iov)
+			memcpy(rw->s.fast_iov + iov_off, fast_iov + iov_off,
+			       sizeof(struct iovec) * iter->nr_segs);
+	} else {
+		req->flags |= REQ_F_NEED_CLEANUP;
+	}
+}
+
+static inline bool io_alloc_async_data(struct io_kiocb *req)
+{
+	WARN_ON_ONCE(!io_op_defs[req->opcode].async_size);
+	req->async_data = kmalloc(io_op_defs[req->opcode].async_size, GFP_KERNEL);
+	if (req->async_data) {
+		req->flags |= REQ_F_ASYNC_DATA;
+		return false;
+	}
+	return true;
+}
+
+static int io_setup_async_rw(struct io_kiocb *req, const struct iovec *iovec,
+			     struct io_rw_state *s, bool force)
+{
+	if (!force && !io_op_defs[req->opcode].needs_async_setup)
+		return 0;
+	if (!req_has_async_data(req)) {
+		struct io_async_rw *iorw;
+
+		if (io_alloc_async_data(req)) {
+			kfree(iovec);
+			return -ENOMEM;
+		}
+
+		io_req_map_rw(req, iovec, s->fast_iov, &s->iter);
+		iorw = req->async_data;
+		/* we've copied and mapped the iter, ensure state is saved */
+		iov_iter_save_state(&iorw->s.iter, &iorw->s.iter_state);
+	}
+	return 0;
+}
+
+static inline int io_rw_prep_async(struct io_kiocb *req, int rw)
+{
+	struct io_async_rw *iorw = req->async_data;
+	struct iovec *iov;
+	int ret;
+
+	/* submission path, ->uring_lock should already be taken */
+	ret = io_import_iovec(rw, req, &iov, &iorw->s, 0);
+	if (unlikely(ret < 0))
+		return ret;
+
+	iorw->bytes_done = 0;
+	iorw->free_iovec = iov;
+	if (iov)
+		req->flags |= REQ_F_NEED_CLEANUP;
+	return 0;
+}
+
+static int io_readv_prep_async(struct io_kiocb *req)
+{
+	return io_rw_prep_async(req, READ);
+}
+
+static int io_writev_prep_async(struct io_kiocb *req)
+{
+	return io_rw_prep_async(req, WRITE);
+}
+
+/*
+ * This is our waitqueue callback handler, registered through __folio_lock_async()
+ * when we initially tried to do the IO with the iocb armed our waitqueue.
+ * This gets called when the page is unlocked, and we generally expect that to
+ * happen when the page IO is completed and the page is now uptodate. This will
+ * queue a task_work based retry of the operation, attempting to copy the data
+ * again. If the latter fails because the page was NOT uptodate, then we will
+ * do a thread based blocking retry of the operation. That's the unexpected
+ * slow path.
+ */
+static int io_async_buf_func(struct wait_queue_entry *wait, unsigned mode,
+			     int sync, void *arg)
+{
+	struct wait_page_queue *wpq;
+	struct io_kiocb *req = wait->private;
+	struct wait_page_key *key = arg;
+
+	wpq = container_of(wait, struct wait_page_queue, wait);
+
+	if (!wake_page_match(wpq, key))
+		return 0;
+
+	req->rw.kiocb.ki_flags &= ~IOCB_WAITQ;
+	list_del_init(&wait->entry);
+	io_req_task_queue(req);
+	return 1;
+}
+
+/*
+ * This controls whether a given IO request should be armed for async page
+ * based retry. If we return false here, the request is handed to the async
+ * worker threads for retry. If we're doing buffered reads on a regular file,
+ * we prepare a private wait_page_queue entry and retry the operation. This
+ * will either succeed because the page is now uptodate and unlocked, or it
+ * will register a callback when the page is unlocked at IO completion. Through
+ * that callback, io_uring uses task_work to setup a retry of the operation.
+ * That retry will attempt the buffered read again. The retry will generally
+ * succeed, or in rare cases where it fails, we then fall back to using the
+ * async worker threads for a blocking retry.
+ */
+static bool io_rw_should_retry(struct io_kiocb *req)
+{
+	struct io_async_rw *rw = req->async_data;
+	struct wait_page_queue *wait = &rw->wpq;
+	struct kiocb *kiocb = &req->rw.kiocb;
+
+	/* never retry for NOWAIT, we just complete with -EAGAIN */
+	if (req->flags & REQ_F_NOWAIT)
+		return false;
+
+	/* Only for buffered IO */
+	if (kiocb->ki_flags & (IOCB_DIRECT | IOCB_HIPRI))
+		return false;
+
+	/*
+	 * just use poll if we can, and don't attempt if the fs doesn't
+	 * support callback based unlocks
+	 */
+	if (file_can_poll(req->file) || !(req->file->f_mode & FMODE_BUF_RASYNC))
+		return false;
+
+	wait->wait.func = io_async_buf_func;
+	wait->wait.private = req;
+	wait->wait.flags = 0;
+	INIT_LIST_HEAD(&wait->wait.entry);
+	kiocb->ki_flags |= IOCB_WAITQ;
+	kiocb->ki_flags &= ~IOCB_NOWAIT;
+	kiocb->ki_waitq = wait;
+	return true;
+}
+
+static inline int io_iter_do_read(struct io_kiocb *req, struct iov_iter *iter)
+{
+	if (likely(req->file->f_op->read_iter))
+		return call_read_iter(req->file, &req->rw.kiocb, iter);
+	else if (req->file->f_op->read)
+		return loop_rw_iter(READ, req, iter);
+	else
+		return -EINVAL;
+}
+
+static bool need_read_all(struct io_kiocb *req)
+{
+	return req->flags & REQ_F_ISREG ||
+		S_ISBLK(file_inode(req->file)->i_mode);
+}
+
+static int io_rw_init_file(struct io_kiocb *req, fmode_t mode)
+{
+	struct kiocb *kiocb = &req->rw.kiocb;
+	struct io_ring_ctx *ctx = req->ctx;
+	struct file *file = req->file;
+	int ret;
+
+	if (unlikely(!file || !(file->f_mode & mode)))
+		return -EBADF;
+
+	if (!io_req_ffs_set(req))
+		req->flags |= io_file_get_flags(file) << REQ_F_SUPPORT_NOWAIT_BIT;
+
+	kiocb->ki_flags = iocb_flags(file);
+	ret = kiocb_set_rw_flags(kiocb, req->rw.flags);
+	if (unlikely(ret))
+		return ret;
+
+	/*
+	 * If the file is marked O_NONBLOCK, still allow retry for it if it
+	 * supports async. Otherwise it's impossible to use O_NONBLOCK files
+	 * reliably. If not, or it IOCB_NOWAIT is set, don't retry.
+	 */
+	if ((kiocb->ki_flags & IOCB_NOWAIT) ||
+	    ((file->f_flags & O_NONBLOCK) && !io_file_supports_nowait(req)))
+		req->flags |= REQ_F_NOWAIT;
+
+	if (ctx->flags & IORING_SETUP_IOPOLL) {
+		if (!(kiocb->ki_flags & IOCB_DIRECT) || !file->f_op->iopoll)
+			return -EOPNOTSUPP;
+
+		kiocb->private = NULL;
+		kiocb->ki_flags |= IOCB_HIPRI | IOCB_ALLOC_CACHE;
+		kiocb->ki_complete = io_complete_rw_iopoll;
+		req->iopoll_completed = 0;
+	} else {
+		if (kiocb->ki_flags & IOCB_HIPRI)
+			return -EINVAL;
+		kiocb->ki_complete = io_complete_rw;
+	}
+
+	return 0;
+}
+
+static int io_read(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_rw_state __s, *s = &__s;
+	struct iovec *iovec;
+	struct kiocb *kiocb = &req->rw.kiocb;
+	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
+	struct io_async_rw *rw;
+	ssize_t ret, ret2;
+	loff_t *ppos;
+
+	if (!req_has_async_data(req)) {
+		ret = io_import_iovec(READ, req, &iovec, s, issue_flags);
+		if (unlikely(ret < 0))
+			return ret;
+	} else {
+		rw = req->async_data;
+		s = &rw->s;
+
+		/*
+		 * Safe and required to re-import if we're using provided
+		 * buffers, as we dropped the selected one before retry.
+		 */
+		if (io_do_buffer_select(req)) {
+			ret = io_import_iovec(READ, req, &iovec, s, issue_flags);
+			if (unlikely(ret < 0))
+				return ret;
+		}
+
+		/*
+		 * We come here from an earlier attempt, restore our state to
+		 * match in case it doesn't. It's cheap enough that we don't
+		 * need to make this conditional.
+		 */
+		iov_iter_restore(&s->iter, &s->iter_state);
+		iovec = NULL;
+	}
+	ret = io_rw_init_file(req, FMODE_READ);
+	if (unlikely(ret)) {
+		kfree(iovec);
+		return ret;
+	}
+	req->cqe.res = iov_iter_count(&s->iter);
+
+	if (force_nonblock) {
+		/* If the file doesn't support async, just async punt */
+		if (unlikely(!io_file_supports_nowait(req))) {
+			ret = io_setup_async_rw(req, iovec, s, true);
+			return ret ?: -EAGAIN;
+		}
+		kiocb->ki_flags |= IOCB_NOWAIT;
+	} else {
+		/* Ensure we clear previously set non-block flag */
+		kiocb->ki_flags &= ~IOCB_NOWAIT;
+	}
+
+	ppos = io_kiocb_update_pos(req);
+
+	ret = rw_verify_area(READ, req->file, ppos, req->cqe.res);
+	if (unlikely(ret)) {
+		kfree(iovec);
+		return ret;
+	}
+
+	ret = io_iter_do_read(req, &s->iter);
+
+	if (ret == -EAGAIN || (req->flags & REQ_F_REISSUE)) {
+		req->flags &= ~REQ_F_REISSUE;
+		/* if we can poll, just do that */
+		if (req->opcode == IORING_OP_READ && file_can_poll(req->file))
+			return -EAGAIN;
+		/* IOPOLL retry should happen for io-wq threads */
+		if (!force_nonblock && !(req->ctx->flags & IORING_SETUP_IOPOLL))
+			goto done;
+		/* no retry on NONBLOCK nor RWF_NOWAIT */
+		if (req->flags & REQ_F_NOWAIT)
+			goto done;
+		ret = 0;
+	} else if (ret == -EIOCBQUEUED) {
+		goto out_free;
+	} else if (ret == req->cqe.res || ret <= 0 || !force_nonblock ||
+		   (req->flags & REQ_F_NOWAIT) || !need_read_all(req)) {
+		/* read all, failed, already did sync or don't want to retry */
+		goto done;
+	}
+
+	/*
+	 * Don't depend on the iter state matching what was consumed, or being
+	 * untouched in case of error. Restore it and we'll advance it
+	 * manually if we need to.
+	 */
+	iov_iter_restore(&s->iter, &s->iter_state);
+
+	ret2 = io_setup_async_rw(req, iovec, s, true);
+	if (ret2)
+		return ret2;
+
+	iovec = NULL;
+	rw = req->async_data;
+	s = &rw->s;
+	/*
+	 * Now use our persistent iterator and state, if we aren't already.
+	 * We've restored and mapped the iter to match.
+	 */
+
+	do {
+		/*
+		 * We end up here because of a partial read, either from
+		 * above or inside this loop. Advance the iter by the bytes
+		 * that were consumed.
+		 */
+		iov_iter_advance(&s->iter, ret);
+		if (!iov_iter_count(&s->iter))
+			break;
+		rw->bytes_done += ret;
+		iov_iter_save_state(&s->iter, &s->iter_state);
+
+		/* if we can retry, do so with the callbacks armed */
+		if (!io_rw_should_retry(req)) {
+			kiocb->ki_flags &= ~IOCB_WAITQ;
+			return -EAGAIN;
+		}
+
+		/*
+		 * Now retry read with the IOCB_WAITQ parts set in the iocb. If
+		 * we get -EIOCBQUEUED, then we'll get a notification when the
+		 * desired page gets unlocked. We can also get a partial read
+		 * here, and if we do, then just retry at the new offset.
+		 */
+		ret = io_iter_do_read(req, &s->iter);
+		if (ret == -EIOCBQUEUED)
+			return 0;
+		/* we got some bytes, but not all. retry. */
+		kiocb->ki_flags &= ~IOCB_WAITQ;
+		iov_iter_restore(&s->iter, &s->iter_state);
+	} while (ret > 0);
+done:
+	kiocb_done(req, ret, issue_flags);
+out_free:
+	/* it's faster to check here then delegate to kfree */
+	if (iovec)
+		kfree(iovec);
+	return 0;
+}
+
+static int io_write(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_rw_state __s, *s = &__s;
+	struct iovec *iovec;
+	struct kiocb *kiocb = &req->rw.kiocb;
+	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
+	ssize_t ret, ret2;
+	loff_t *ppos;
+
+	if (!req_has_async_data(req)) {
+		ret = io_import_iovec(WRITE, req, &iovec, s, issue_flags);
+		if (unlikely(ret < 0))
+			return ret;
+	} else {
+		struct io_async_rw *rw = req->async_data;
+
+		s = &rw->s;
+		iov_iter_restore(&s->iter, &s->iter_state);
+		iovec = NULL;
+	}
+	ret = io_rw_init_file(req, FMODE_WRITE);
+	if (unlikely(ret)) {
+		kfree(iovec);
+		return ret;
+	}
+	req->cqe.res = iov_iter_count(&s->iter);
+
+	if (force_nonblock) {
+		/* If the file doesn't support async, just async punt */
+		if (unlikely(!io_file_supports_nowait(req)))
+			goto copy_iov;
+
+		/* file path doesn't support NOWAIT for non-direct_IO */
+		if (force_nonblock && !(kiocb->ki_flags & IOCB_DIRECT) &&
+		    (req->flags & REQ_F_ISREG))
+			goto copy_iov;
+
+		kiocb->ki_flags |= IOCB_NOWAIT;
+	} else {
+		/* Ensure we clear previously set non-block flag */
+		kiocb->ki_flags &= ~IOCB_NOWAIT;
+	}
+
+	ppos = io_kiocb_update_pos(req);
+
+	ret = rw_verify_area(WRITE, req->file, ppos, req->cqe.res);
+	if (unlikely(ret))
+		goto out_free;
+
+	/*
+	 * Open-code file_start_write here to grab freeze protection,
+	 * which will be released by another thread in
+	 * io_complete_rw().  Fool lockdep by telling it the lock got
+	 * released so that it doesn't complain about the held lock when
+	 * we return to userspace.
+	 */
+	if (req->flags & REQ_F_ISREG) {
+		sb_start_write(file_inode(req->file)->i_sb);
+		__sb_writers_release(file_inode(req->file)->i_sb,
+					SB_FREEZE_WRITE);
+	}
+	kiocb->ki_flags |= IOCB_WRITE;
+
+	if (likely(req->file->f_op->write_iter))
+		ret2 = call_write_iter(req->file, kiocb, &s->iter);
+	else if (req->file->f_op->write)
+		ret2 = loop_rw_iter(WRITE, req, &s->iter);
+	else
+		ret2 = -EINVAL;
+
+	if (req->flags & REQ_F_REISSUE) {
+		req->flags &= ~REQ_F_REISSUE;
+		ret2 = -EAGAIN;
+	}
+
+	/*
+	 * Raw bdev writes will return -EOPNOTSUPP for IOCB_NOWAIT. Just
+	 * retry them without IOCB_NOWAIT.
+	 */
+	if (ret2 == -EOPNOTSUPP && (kiocb->ki_flags & IOCB_NOWAIT))
+		ret2 = -EAGAIN;
+	/* no retry on NONBLOCK nor RWF_NOWAIT */
+	if (ret2 == -EAGAIN && (req->flags & REQ_F_NOWAIT))
+		goto done;
+	if (!force_nonblock || ret2 != -EAGAIN) {
+		/* IOPOLL retry should happen for io-wq threads */
+		if (ret2 == -EAGAIN && (req->ctx->flags & IORING_SETUP_IOPOLL))
+			goto copy_iov;
+done:
+		kiocb_done(req, ret2, issue_flags);
+	} else {
+copy_iov:
+		iov_iter_restore(&s->iter, &s->iter_state);
+		ret = io_setup_async_rw(req, iovec, s, false);
+		return ret ?: -EAGAIN;
+	}
+out_free:
+	/* it's reportedly faster than delegating the null check to kfree() */
+	if (iovec)
+		kfree(iovec);
+	return ret;
+}
+
+static int io_renameat_prep(struct io_kiocb *req,
+			    const struct io_uring_sqe *sqe)
+{
+	struct io_rename *ren = &req->rename;
+	const char __user *oldf, *newf;
+
+	if (sqe->buf_index || sqe->splice_fd_in)
+		return -EINVAL;
+	if (unlikely(req->flags & REQ_F_FIXED_FILE))
+		return -EBADF;
+
+	ren->old_dfd = READ_ONCE(sqe->fd);
+	oldf = u64_to_user_ptr(READ_ONCE(sqe->addr));
+	newf = u64_to_user_ptr(READ_ONCE(sqe->addr2));
+	ren->new_dfd = READ_ONCE(sqe->len);
+	ren->flags = READ_ONCE(sqe->rename_flags);
+
+	ren->oldpath = getname(oldf);
+	if (IS_ERR(ren->oldpath))
+		return PTR_ERR(ren->oldpath);
+
+	ren->newpath = getname(newf);
+	if (IS_ERR(ren->newpath)) {
+		putname(ren->oldpath);
+		return PTR_ERR(ren->newpath);
+	}
+
+	req->flags |= REQ_F_NEED_CLEANUP;
+	return 0;
+}
+
+static int io_renameat(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_rename *ren = &req->rename;
+	int ret;
+
+	if (issue_flags & IO_URING_F_NONBLOCK)
+		return -EAGAIN;
+
+	ret = do_renameat2(ren->old_dfd, ren->oldpath, ren->new_dfd,
+				ren->newpath, ren->flags);
+
+	req->flags &= ~REQ_F_NEED_CLEANUP;
+	io_req_complete(req, ret);
+	return 0;
+}
+
+static inline void __io_xattr_finish(struct io_kiocb *req)
+{
+	struct io_xattr *ix = &req->xattr;
+
+	if (ix->filename)
+		putname(ix->filename);
+
+	kfree(ix->ctx.kname);
+	kvfree(ix->ctx.kvalue);
+}
+
+static void io_xattr_finish(struct io_kiocb *req, int ret)
+{
+	req->flags &= ~REQ_F_NEED_CLEANUP;
+
+	__io_xattr_finish(req);
+	io_req_complete(req, ret);
+}
+
+static int __io_getxattr_prep(struct io_kiocb *req,
+			      const struct io_uring_sqe *sqe)
+{
+	struct io_xattr *ix = &req->xattr;
+	const char __user *name;
+	int ret;
+
+	if (unlikely(req->flags & REQ_F_FIXED_FILE))
+		return -EBADF;
+
+	ix->filename = NULL;
+	ix->ctx.kvalue = NULL;
+	name = u64_to_user_ptr(READ_ONCE(sqe->addr));
+	ix->ctx.cvalue = u64_to_user_ptr(READ_ONCE(sqe->addr2));
+	ix->ctx.size = READ_ONCE(sqe->len);
+	ix->ctx.flags = READ_ONCE(sqe->xattr_flags);
+
+	if (ix->ctx.flags)
+		return -EINVAL;
+
+	ix->ctx.kname = kmalloc(sizeof(*ix->ctx.kname), GFP_KERNEL);
+	if (!ix->ctx.kname)
+		return -ENOMEM;
+
+	ret = strncpy_from_user(ix->ctx.kname->name, name,
+				sizeof(ix->ctx.kname->name));
+	if (!ret || ret == sizeof(ix->ctx.kname->name))
+		ret = -ERANGE;
+	if (ret < 0) {
+		kfree(ix->ctx.kname);
+		return ret;
+	}
+
+	req->flags |= REQ_F_NEED_CLEANUP;
+	return 0;
+}
+
+static int io_fgetxattr_prep(struct io_kiocb *req,
+			     const struct io_uring_sqe *sqe)
+{
+	return __io_getxattr_prep(req, sqe);
+}
+
+static int io_getxattr_prep(struct io_kiocb *req,
+			    const struct io_uring_sqe *sqe)
+{
+	struct io_xattr *ix = &req->xattr;
+	const char __user *path;
+	int ret;
+
+	ret = __io_getxattr_prep(req, sqe);
+	if (ret)
+		return ret;
+
+	path = u64_to_user_ptr(READ_ONCE(sqe->addr3));
+
+	ix->filename = getname_flags(path, LOOKUP_FOLLOW, NULL);
+	if (IS_ERR(ix->filename)) {
+		ret = PTR_ERR(ix->filename);
+		ix->filename = NULL;
+	}
+
+	return ret;
+}
+
+static int io_fgetxattr(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_xattr *ix = &req->xattr;
+	int ret;
+
+	if (issue_flags & IO_URING_F_NONBLOCK)
+		return -EAGAIN;
+
+	ret = do_getxattr(mnt_user_ns(req->file->f_path.mnt),
+			req->file->f_path.dentry,
+			&ix->ctx);
+
+	io_xattr_finish(req, ret);
+	return 0;
+}
+
+static int io_getxattr(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_xattr *ix = &req->xattr;
+	unsigned int lookup_flags = LOOKUP_FOLLOW;
+	struct path path;
+	int ret;
+
+	if (issue_flags & IO_URING_F_NONBLOCK)
+		return -EAGAIN;
+
+retry:
+	ret = filename_lookup(AT_FDCWD, ix->filename, lookup_flags, &path, NULL);
+	if (!ret) {
+		ret = do_getxattr(mnt_user_ns(path.mnt),
+				path.dentry,
+				&ix->ctx);
+
+		path_put(&path);
+		if (retry_estale(ret, lookup_flags)) {
+			lookup_flags |= LOOKUP_REVAL;
+			goto retry;
+		}
+	}
+
+	io_xattr_finish(req, ret);
+	return 0;
+}
+
+static int __io_setxattr_prep(struct io_kiocb *req,
+			const struct io_uring_sqe *sqe)
+{
+	struct io_xattr *ix = &req->xattr;
+	const char __user *name;
+	int ret;
+
+	if (unlikely(req->flags & REQ_F_FIXED_FILE))
+		return -EBADF;
+
+	ix->filename = NULL;
+	name = u64_to_user_ptr(READ_ONCE(sqe->addr));
+	ix->ctx.cvalue = u64_to_user_ptr(READ_ONCE(sqe->addr2));
+	ix->ctx.kvalue = NULL;
+	ix->ctx.size = READ_ONCE(sqe->len);
+	ix->ctx.flags = READ_ONCE(sqe->xattr_flags);
+
+	ix->ctx.kname = kmalloc(sizeof(*ix->ctx.kname), GFP_KERNEL);
+	if (!ix->ctx.kname)
+		return -ENOMEM;
+
+	ret = setxattr_copy(name, &ix->ctx);
+	if (ret) {
+		kfree(ix->ctx.kname);
+		return ret;
+	}
+
+	req->flags |= REQ_F_NEED_CLEANUP;
+	return 0;
+}
+
+static int io_setxattr_prep(struct io_kiocb *req,
+			const struct io_uring_sqe *sqe)
+{
+	struct io_xattr *ix = &req->xattr;
+	const char __user *path;
+	int ret;
+
+	ret = __io_setxattr_prep(req, sqe);
+	if (ret)
+		return ret;
+
+	path = u64_to_user_ptr(READ_ONCE(sqe->addr3));
+
+	ix->filename = getname_flags(path, LOOKUP_FOLLOW, NULL);
+	if (IS_ERR(ix->filename)) {
+		ret = PTR_ERR(ix->filename);
+		ix->filename = NULL;
+	}
+
+	return ret;
+}
+
+static int io_fsetxattr_prep(struct io_kiocb *req,
+			const struct io_uring_sqe *sqe)
+{
+	return __io_setxattr_prep(req, sqe);
+}
+
+static int __io_setxattr(struct io_kiocb *req, unsigned int issue_flags,
+			struct path *path)
+{
+	struct io_xattr *ix = &req->xattr;
+	int ret;
+
+	ret = mnt_want_write(path->mnt);
+	if (!ret) {
+		ret = do_setxattr(mnt_user_ns(path->mnt), path->dentry, &ix->ctx);
+		mnt_drop_write(path->mnt);
+	}
+
+	return ret;
+}
+
+static int io_fsetxattr(struct io_kiocb *req, unsigned int issue_flags)
+{
+	int ret;
+
+	if (issue_flags & IO_URING_F_NONBLOCK)
+		return -EAGAIN;
+
+	ret = __io_setxattr(req, issue_flags, &req->file->f_path);
+	io_xattr_finish(req, ret);
+
+	return 0;
+}
+
+static int io_setxattr(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_xattr *ix = &req->xattr;
+	unsigned int lookup_flags = LOOKUP_FOLLOW;
+	struct path path;
+	int ret;
+
+	if (issue_flags & IO_URING_F_NONBLOCK)
+		return -EAGAIN;
+
+retry:
+	ret = filename_lookup(AT_FDCWD, ix->filename, lookup_flags, &path, NULL);
+	if (!ret) {
+		ret = __io_setxattr(req, issue_flags, &path);
+		path_put(&path);
+		if (retry_estale(ret, lookup_flags)) {
+			lookup_flags |= LOOKUP_REVAL;
+			goto retry;
+		}
+	}
+
+	io_xattr_finish(req, ret);
+	return 0;
+}
+
+static int io_unlinkat_prep(struct io_kiocb *req,
+			    const struct io_uring_sqe *sqe)
+{
+	struct io_unlink *un = &req->unlink;
+	const char __user *fname;
+
+	if (sqe->off || sqe->len || sqe->buf_index || sqe->splice_fd_in)
+		return -EINVAL;
+	if (unlikely(req->flags & REQ_F_FIXED_FILE))
+		return -EBADF;
+
+	un->dfd = READ_ONCE(sqe->fd);
+
+	un->flags = READ_ONCE(sqe->unlink_flags);
+	if (un->flags & ~AT_REMOVEDIR)
+		return -EINVAL;
+
+	fname = u64_to_user_ptr(READ_ONCE(sqe->addr));
+	un->filename = getname(fname);
+	if (IS_ERR(un->filename))
+		return PTR_ERR(un->filename);
+
+	req->flags |= REQ_F_NEED_CLEANUP;
+	return 0;
+}
+
+static int io_unlinkat(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_unlink *un = &req->unlink;
+	int ret;
+
+	if (issue_flags & IO_URING_F_NONBLOCK)
+		return -EAGAIN;
+
+	if (un->flags & AT_REMOVEDIR)
+		ret = do_rmdir(un->dfd, un->filename);
+	else
+		ret = do_unlinkat(un->dfd, un->filename);
+
+	req->flags &= ~REQ_F_NEED_CLEANUP;
+	io_req_complete(req, ret);
+	return 0;
+}
+
+static int io_mkdirat_prep(struct io_kiocb *req,
+			    const struct io_uring_sqe *sqe)
+{
+	struct io_mkdir *mkd = &req->mkdir;
+	const char __user *fname;
+
+	if (sqe->off || sqe->rw_flags || sqe->buf_index || sqe->splice_fd_in)
+		return -EINVAL;
+	if (unlikely(req->flags & REQ_F_FIXED_FILE))
+		return -EBADF;
+
+	mkd->dfd = READ_ONCE(sqe->fd);
+	mkd->mode = READ_ONCE(sqe->len);
+
+	fname = u64_to_user_ptr(READ_ONCE(sqe->addr));
+	mkd->filename = getname(fname);
+	if (IS_ERR(mkd->filename))
+		return PTR_ERR(mkd->filename);
+
+	req->flags |= REQ_F_NEED_CLEANUP;
+	return 0;
+}
+
+static int io_mkdirat(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_mkdir *mkd = &req->mkdir;
+	int ret;
+
+	if (issue_flags & IO_URING_F_NONBLOCK)
+		return -EAGAIN;
+
+	ret = do_mkdirat(mkd->dfd, mkd->filename, mkd->mode);
+
+	req->flags &= ~REQ_F_NEED_CLEANUP;
+	io_req_complete(req, ret);
+	return 0;
+}
+
+static int io_symlinkat_prep(struct io_kiocb *req,
+			    const struct io_uring_sqe *sqe)
+{
+	struct io_symlink *sl = &req->symlink;
+	const char __user *oldpath, *newpath;
+
+	if (sqe->len || sqe->rw_flags || sqe->buf_index || sqe->splice_fd_in)
+		return -EINVAL;
+	if (unlikely(req->flags & REQ_F_FIXED_FILE))
+		return -EBADF;
+
+	sl->new_dfd = READ_ONCE(sqe->fd);
+	oldpath = u64_to_user_ptr(READ_ONCE(sqe->addr));
+	newpath = u64_to_user_ptr(READ_ONCE(sqe->addr2));
+
+	sl->oldpath = getname(oldpath);
+	if (IS_ERR(sl->oldpath))
+		return PTR_ERR(sl->oldpath);
+
+	sl->newpath = getname(newpath);
+	if (IS_ERR(sl->newpath)) {
+		putname(sl->oldpath);
+		return PTR_ERR(sl->newpath);
+	}
+
+	req->flags |= REQ_F_NEED_CLEANUP;
+	return 0;
+}
+
+static int io_symlinkat(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_symlink *sl = &req->symlink;
+	int ret;
+
+	if (issue_flags & IO_URING_F_NONBLOCK)
+		return -EAGAIN;
+
+	ret = do_symlinkat(sl->oldpath, sl->new_dfd, sl->newpath);
+
+	req->flags &= ~REQ_F_NEED_CLEANUP;
+	io_req_complete(req, ret);
+	return 0;
+}
+
+static int io_linkat_prep(struct io_kiocb *req,
+			    const struct io_uring_sqe *sqe)
+{
+	struct io_hardlink *lnk = &req->hardlink;
+	const char __user *oldf, *newf;
+
+	if (sqe->rw_flags || sqe->buf_index || sqe->splice_fd_in)
+		return -EINVAL;
+	if (unlikely(req->flags & REQ_F_FIXED_FILE))
+		return -EBADF;
+
+	lnk->old_dfd = READ_ONCE(sqe->fd);
+	lnk->new_dfd = READ_ONCE(sqe->len);
+	oldf = u64_to_user_ptr(READ_ONCE(sqe->addr));
+	newf = u64_to_user_ptr(READ_ONCE(sqe->addr2));
+	lnk->flags = READ_ONCE(sqe->hardlink_flags);
+
+	lnk->oldpath = getname(oldf);
+	if (IS_ERR(lnk->oldpath))
+		return PTR_ERR(lnk->oldpath);
+
+	lnk->newpath = getname(newf);
+	if (IS_ERR(lnk->newpath)) {
+		putname(lnk->oldpath);
+		return PTR_ERR(lnk->newpath);
+	}
+
+	req->flags |= REQ_F_NEED_CLEANUP;
+	return 0;
+}
+
+static int io_linkat(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_hardlink *lnk = &req->hardlink;
+	int ret;
+
+	if (issue_flags & IO_URING_F_NONBLOCK)
+		return -EAGAIN;
+
+	ret = do_linkat(lnk->old_dfd, lnk->oldpath, lnk->new_dfd,
+				lnk->newpath, lnk->flags);
+
+	req->flags &= ~REQ_F_NEED_CLEANUP;
+	io_req_complete(req, ret);
+	return 0;
+}
+
+static void io_uring_cmd_work(struct io_kiocb *req, bool *locked)
+{
+	req->uring_cmd.task_work_cb(&req->uring_cmd);
+}
+
+void io_uring_cmd_complete_in_task(struct io_uring_cmd *ioucmd,
+			void (*task_work_cb)(struct io_uring_cmd *))
+{
+	struct io_kiocb *req = container_of(ioucmd, struct io_kiocb, uring_cmd);
+
+	req->uring_cmd.task_work_cb = task_work_cb;
+	req->io_task_work.func = io_uring_cmd_work;
+	io_req_task_work_add(req);
+}
+EXPORT_SYMBOL_GPL(io_uring_cmd_complete_in_task);
+
+static inline void io_req_set_cqe32_extra(struct io_kiocb *req,
+					  u64 extra1, u64 extra2)
+{
+	req->extra1 = extra1;
+	req->extra2 = extra2;
+	req->flags |= REQ_F_CQE32_INIT;
+}
+
+/*
+ * Called by consumers of io_uring_cmd, if they originally returned
+ * -EIOCBQUEUED upon receiving the command.
+ */
+void io_uring_cmd_done(struct io_uring_cmd *ioucmd, ssize_t ret, ssize_t res2)
+{
+	struct io_kiocb *req = container_of(ioucmd, struct io_kiocb, uring_cmd);
+
+	if (ret < 0)
+		req_set_fail(req);
+
+	if (req->ctx->flags & IORING_SETUP_CQE32)
+		io_req_set_cqe32_extra(req, res2, 0);
+	io_req_complete(req, ret);
+}
+EXPORT_SYMBOL_GPL(io_uring_cmd_done);
+
+static int io_uring_cmd_prep_async(struct io_kiocb *req)
+{
+	size_t cmd_size;
+
+	cmd_size = uring_cmd_pdu_size(req->ctx->flags & IORING_SETUP_SQE128);
+
+	memcpy(req->async_data, req->uring_cmd.cmd, cmd_size);
+	return 0;
+}
+
+static int io_uring_cmd_prep(struct io_kiocb *req,
+			     const struct io_uring_sqe *sqe)
+{
+	struct io_uring_cmd *ioucmd = &req->uring_cmd;
+
+	if (sqe->rw_flags || sqe->__pad1)
+		return -EINVAL;
+	ioucmd->cmd = sqe->cmd;
+	ioucmd->cmd_op = READ_ONCE(sqe->cmd_op);
+	return 0;
+}
+
+static int io_uring_cmd(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_uring_cmd *ioucmd = &req->uring_cmd;
+	struct io_ring_ctx *ctx = req->ctx;
+	struct file *file = req->file;
+	int ret;
+
+	if (!req->file->f_op->uring_cmd)
+		return -EOPNOTSUPP;
+
+	if (ctx->flags & IORING_SETUP_SQE128)
+		issue_flags |= IO_URING_F_SQE128;
+	if (ctx->flags & IORING_SETUP_CQE32)
+		issue_flags |= IO_URING_F_CQE32;
+	if (ctx->flags & IORING_SETUP_IOPOLL)
+		issue_flags |= IO_URING_F_IOPOLL;
+
+	if (req_has_async_data(req))
+		ioucmd->cmd = req->async_data;
+
+	ret = file->f_op->uring_cmd(ioucmd, issue_flags);
+	if (ret == -EAGAIN) {
+		if (!req_has_async_data(req)) {
+			if (io_alloc_async_data(req))
+				return -ENOMEM;
+			io_uring_cmd_prep_async(req);
+		}
+		return -EAGAIN;
+	}
+
+	if (ret != -EIOCBQUEUED)
+		io_uring_cmd_done(ioucmd, ret, 0);
+	return 0;
+}
+
+static int __io_splice_prep(struct io_kiocb *req,
+			    const struct io_uring_sqe *sqe)
+{
+	struct io_splice *sp = &req->splice;
+	unsigned int valid_flags = SPLICE_F_FD_IN_FIXED | SPLICE_F_ALL;
+
+	sp->len = READ_ONCE(sqe->len);
+	sp->flags = READ_ONCE(sqe->splice_flags);
+	if (unlikely(sp->flags & ~valid_flags))
+		return -EINVAL;
+	sp->splice_fd_in = READ_ONCE(sqe->splice_fd_in);
+	return 0;
+}
+
+static int io_tee_prep(struct io_kiocb *req,
+		       const struct io_uring_sqe *sqe)
+{
+	if (READ_ONCE(sqe->splice_off_in) || READ_ONCE(sqe->off))
+		return -EINVAL;
+	return __io_splice_prep(req, sqe);
+}
+
+static int io_tee(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_splice *sp = &req->splice;
+	struct file *out = sp->file_out;
+	unsigned int flags = sp->flags & ~SPLICE_F_FD_IN_FIXED;
+	struct file *in;
+	long ret = 0;
+
+	if (issue_flags & IO_URING_F_NONBLOCK)
+		return -EAGAIN;
+
+	if (sp->flags & SPLICE_F_FD_IN_FIXED)
+		in = io_file_get_fixed(req, sp->splice_fd_in, issue_flags);
+	else
+		in = io_file_get_normal(req, sp->splice_fd_in);
+	if (!in) {
+		ret = -EBADF;
+		goto done;
+	}
+
+	if (sp->len)
+		ret = do_tee(in, out, sp->len, flags);
+
+	if (!(sp->flags & SPLICE_F_FD_IN_FIXED))
+		io_put_file(in);
+done:
+	if (ret != sp->len)
+		req_set_fail(req);
+	__io_req_complete(req, 0, ret, 0);
+	return 0;
+}
+
+static int io_splice_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+	struct io_splice *sp = &req->splice;
+
+	sp->off_in = READ_ONCE(sqe->splice_off_in);
+	sp->off_out = READ_ONCE(sqe->off);
+	return __io_splice_prep(req, sqe);
+}
+
+static int io_splice(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_splice *sp = &req->splice;
+	struct file *out = sp->file_out;
+	unsigned int flags = sp->flags & ~SPLICE_F_FD_IN_FIXED;
+	loff_t *poff_in, *poff_out;
+	struct file *in;
+	long ret = 0;
+
+	if (issue_flags & IO_URING_F_NONBLOCK)
+		return -EAGAIN;
+
+	if (sp->flags & SPLICE_F_FD_IN_FIXED)
+		in = io_file_get_fixed(req, sp->splice_fd_in, issue_flags);
+	else
+		in = io_file_get_normal(req, sp->splice_fd_in);
+	if (!in) {
+		ret = -EBADF;
+		goto done;
+	}
+
+	poff_in = (sp->off_in == -1) ? NULL : &sp->off_in;
+	poff_out = (sp->off_out == -1) ? NULL : &sp->off_out;
+
+	if (sp->len)
+		ret = do_splice(in, poff_in, out, poff_out, sp->len, flags);
+
+	if (!(sp->flags & SPLICE_F_FD_IN_FIXED))
+		io_put_file(in);
+done:
+	if (ret != sp->len)
+		req_set_fail(req);
+	__io_req_complete(req, 0, ret, 0);
+	return 0;
+}
+
+static int io_nop_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+	return 0;
+}
+
+/*
+ * IORING_OP_NOP just posts a completion event, nothing else.
+ */
+static int io_nop(struct io_kiocb *req, unsigned int issue_flags)
+{
+	__io_req_complete(req, issue_flags, 0, 0);
+	return 0;
+}
+
+static int io_msg_ring_prep(struct io_kiocb *req,
+			    const struct io_uring_sqe *sqe)
+{
+	if (unlikely(sqe->addr || sqe->rw_flags || sqe->splice_fd_in ||
+		     sqe->buf_index || sqe->personality))
+		return -EINVAL;
+
+	req->msg.user_data = READ_ONCE(sqe->off);
+	req->msg.len = READ_ONCE(sqe->len);
+	return 0;
+}
+
+static int io_msg_ring(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_ring_ctx *target_ctx;
+	struct io_msg *msg = &req->msg;
+	bool filled;
+	int ret;
+
+	ret = -EBADFD;
+	if (req->file->f_op != &io_uring_fops)
+		goto done;
+
+	ret = -EOVERFLOW;
+	target_ctx = req->file->private_data;
+
+	spin_lock(&target_ctx->completion_lock);
+	filled = io_fill_cqe_aux(target_ctx, msg->user_data, msg->len, 0);
+	io_commit_cqring(target_ctx);
+	spin_unlock(&target_ctx->completion_lock);
+
+	if (filled) {
+		io_cqring_ev_posted(target_ctx);
+		ret = 0;
+	}
+
+done:
+	if (ret < 0)
+		req_set_fail(req);
+	__io_req_complete(req, issue_flags, ret, 0);
+	/* put file to avoid an attempt to IOPOLL the req */
+	io_put_file(req->file);
+	req->file = NULL;
+	return 0;
+}
+
+static int io_fsync_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+	if (unlikely(sqe->addr || sqe->buf_index || sqe->splice_fd_in))
+		return -EINVAL;
+
+	req->sync.flags = READ_ONCE(sqe->fsync_flags);
+	if (unlikely(req->sync.flags & ~IORING_FSYNC_DATASYNC))
+		return -EINVAL;
+
+	req->sync.off = READ_ONCE(sqe->off);
+	req->sync.len = READ_ONCE(sqe->len);
+	return 0;
+}
+
+static int io_fsync(struct io_kiocb *req, unsigned int issue_flags)
+{
+	loff_t end = req->sync.off + req->sync.len;
+	int ret;
+
+	/* fsync always requires a blocking context */
+	if (issue_flags & IO_URING_F_NONBLOCK)
+		return -EAGAIN;
+
+	ret = vfs_fsync_range(req->file, req->sync.off,
+				end > 0 ? end : LLONG_MAX,
+				req->sync.flags & IORING_FSYNC_DATASYNC);
+	io_req_complete(req, ret);
+	return 0;
+}
+
+static int io_fallocate_prep(struct io_kiocb *req,
+			     const struct io_uring_sqe *sqe)
+{
+	if (sqe->buf_index || sqe->rw_flags || sqe->splice_fd_in)
+		return -EINVAL;
+
+	req->sync.off = READ_ONCE(sqe->off);
+	req->sync.len = READ_ONCE(sqe->addr);
+	req->sync.mode = READ_ONCE(sqe->len);
+	return 0;
+}
+
+static int io_fallocate(struct io_kiocb *req, unsigned int issue_flags)
+{
+	int ret;
+
+	/* fallocate always requiring blocking context */
+	if (issue_flags & IO_URING_F_NONBLOCK)
+		return -EAGAIN;
+	ret = vfs_fallocate(req->file, req->sync.mode, req->sync.off,
+				req->sync.len);
+	if (ret >= 0)
+		fsnotify_modify(req->file);
+	io_req_complete(req, ret);
+	return 0;
+}
+
+static int __io_openat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+	const char __user *fname;
+	int ret;
+
+	if (unlikely(sqe->buf_index))
+		return -EINVAL;
+	if (unlikely(req->flags & REQ_F_FIXED_FILE))
+		return -EBADF;
+
+	/* open.how should be already initialised */
+	if (!(req->open.how.flags & O_PATH) && force_o_largefile())
+		req->open.how.flags |= O_LARGEFILE;
+
+	req->open.dfd = READ_ONCE(sqe->fd);
+	fname = u64_to_user_ptr(READ_ONCE(sqe->addr));
+	req->open.filename = getname(fname);
+	if (IS_ERR(req->open.filename)) {
+		ret = PTR_ERR(req->open.filename);
+		req->open.filename = NULL;
+		return ret;
+	}
+
+	req->open.file_slot = READ_ONCE(sqe->file_index);
+	if (req->open.file_slot && (req->open.how.flags & O_CLOEXEC))
+		return -EINVAL;
+
+	req->open.nofile = rlimit(RLIMIT_NOFILE);
+	req->flags |= REQ_F_NEED_CLEANUP;
+	return 0;
+}
+
+static int io_openat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+	u64 mode = READ_ONCE(sqe->len);
+	u64 flags = READ_ONCE(sqe->open_flags);
+
+	req->open.how = build_open_how(flags, mode);
+	return __io_openat_prep(req, sqe);
+}
+
+static int io_openat2_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+	struct open_how __user *how;
+	size_t len;
+	int ret;
+
+	how = u64_to_user_ptr(READ_ONCE(sqe->addr2));
+	len = READ_ONCE(sqe->len);
+	if (len < OPEN_HOW_SIZE_VER0)
+		return -EINVAL;
+
+	ret = copy_struct_from_user(&req->open.how, sizeof(req->open.how), how,
+					len);
+	if (ret)
+		return ret;
+
+	return __io_openat_prep(req, sqe);
+}
+
+static int io_file_bitmap_get(struct io_ring_ctx *ctx)
+{
+	struct io_file_table *table = &ctx->file_table;
+	unsigned long nr = ctx->nr_user_files;
+	int ret;
+
+	do {
+		ret = find_next_zero_bit(table->bitmap, nr, table->alloc_hint);
+		if (ret != nr)
+			return ret;
+
+		if (!table->alloc_hint)
+			break;
+
+		nr = table->alloc_hint;
+		table->alloc_hint = 0;
+	} while (1);
+
+	return -ENFILE;
+}
+
+/*
+ * Note when io_fixed_fd_install() returns error value, it will ensure
+ * fput() is called correspondingly.
+ */
+static int io_fixed_fd_install(struct io_kiocb *req, unsigned int issue_flags,
+			       struct file *file, unsigned int file_slot)
+{
+	bool alloc_slot = file_slot == IORING_FILE_INDEX_ALLOC;
+	struct io_ring_ctx *ctx = req->ctx;
+	int ret;
+
+	io_ring_submit_lock(ctx, issue_flags);
+
+	if (alloc_slot) {
+		ret = io_file_bitmap_get(ctx);
+		if (unlikely(ret < 0))
+			goto err;
+		file_slot = ret;
+	} else {
+		file_slot--;
+	}
+
+	ret = io_install_fixed_file(req, file, issue_flags, file_slot);
+	if (!ret && alloc_slot)
+		ret = file_slot;
+err:
+	io_ring_submit_unlock(ctx, issue_flags);
+	if (unlikely(ret < 0))
+		fput(file);
+	return ret;
+}
+
+static int io_openat2(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct open_flags op;
+	struct file *file;
+	bool resolve_nonblock, nonblock_set;
+	bool fixed = !!req->open.file_slot;
+	int ret;
+
+	ret = build_open_flags(&req->open.how, &op);
+	if (ret)
+		goto err;
+	nonblock_set = op.open_flag & O_NONBLOCK;
+	resolve_nonblock = req->open.how.resolve & RESOLVE_CACHED;
+	if (issue_flags & IO_URING_F_NONBLOCK) {
+		/*
+		 * Don't bother trying for O_TRUNC, O_CREAT, or O_TMPFILE open,
+		 * it'll always -EAGAIN
+		 */
+		if (req->open.how.flags & (O_TRUNC | O_CREAT | O_TMPFILE))
+			return -EAGAIN;
+		op.lookup_flags |= LOOKUP_CACHED;
+		op.open_flag |= O_NONBLOCK;
+	}
+
+	if (!fixed) {
+		ret = __get_unused_fd_flags(req->open.how.flags, req->open.nofile);
+		if (ret < 0)
+			goto err;
+	}
+
+	file = do_filp_open(req->open.dfd, req->open.filename, &op);
+	if (IS_ERR(file)) {
+		/*
+		 * We could hang on to this 'fd' on retrying, but seems like
+		 * marginal gain for something that is now known to be a slower
+		 * path. So just put it, and we'll get a new one when we retry.
+		 */
+		if (!fixed)
+			put_unused_fd(ret);
+
+		ret = PTR_ERR(file);
+		/* only retry if RESOLVE_CACHED wasn't already set by application */
+		if (ret == -EAGAIN &&
+		    (!resolve_nonblock && (issue_flags & IO_URING_F_NONBLOCK)))
+			return -EAGAIN;
+		goto err;
+	}
+
+	if ((issue_flags & IO_URING_F_NONBLOCK) && !nonblock_set)
+		file->f_flags &= ~O_NONBLOCK;
+	fsnotify_open(file);
+
+	if (!fixed)
+		fd_install(ret, file);
+	else
+		ret = io_fixed_fd_install(req, issue_flags, file,
+						req->open.file_slot);
+err:
+	putname(req->open.filename);
+	req->flags &= ~REQ_F_NEED_CLEANUP;
+	if (ret < 0)
+		req_set_fail(req);
+	__io_req_complete(req, issue_flags, ret, 0);
+	return 0;
+}
+
+static int io_openat(struct io_kiocb *req, unsigned int issue_flags)
+{
+	return io_openat2(req, issue_flags);
+}
+
+static int io_remove_buffers_prep(struct io_kiocb *req,
+				  const struct io_uring_sqe *sqe)
+{
+	struct io_provide_buf *p = &req->pbuf;
+	u64 tmp;
+
+	if (sqe->rw_flags || sqe->addr || sqe->len || sqe->off ||
+	    sqe->splice_fd_in)
+		return -EINVAL;
+
+	tmp = READ_ONCE(sqe->fd);
+	if (!tmp || tmp > USHRT_MAX)
+		return -EINVAL;
+
+	memset(p, 0, sizeof(*p));
+	p->nbufs = tmp;
+	p->bgid = READ_ONCE(sqe->buf_group);
+	return 0;
+}
+
+static int __io_remove_buffers(struct io_ring_ctx *ctx,
+			       struct io_buffer_list *bl, unsigned nbufs)
+{
+	unsigned i = 0;
+
+	/* shouldn't happen */
+	if (!nbufs)
+		return 0;
+
+	if (bl->buf_nr_pages) {
+		int j;
+
+		i = bl->buf_ring->tail - bl->head;
+		for (j = 0; j < bl->buf_nr_pages; j++)
+			unpin_user_page(bl->buf_pages[j]);
+		kvfree(bl->buf_pages);
+		bl->buf_pages = NULL;
+		bl->buf_nr_pages = 0;
+		/* make sure it's seen as empty */
+		INIT_LIST_HEAD(&bl->buf_list);
+		return i;
+	}
+
+	/* the head kbuf is the list itself */
+	while (!list_empty(&bl->buf_list)) {
+		struct io_buffer *nxt;
+
+		nxt = list_first_entry(&bl->buf_list, struct io_buffer, list);
+		list_del(&nxt->list);
+		if (++i == nbufs)
+			return i;
+		cond_resched();
+	}
+	i++;
+
+	return i;
+}
+
+static int io_remove_buffers(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_provide_buf *p = &req->pbuf;
+	struct io_ring_ctx *ctx = req->ctx;
+	struct io_buffer_list *bl;
+	int ret = 0;
+
+	io_ring_submit_lock(ctx, issue_flags);
+
+	ret = -ENOENT;
+	bl = io_buffer_get_list(ctx, p->bgid);
+	if (bl) {
+		ret = -EINVAL;
+		/* can't use provide/remove buffers command on mapped buffers */
+		if (!bl->buf_nr_pages)
+			ret = __io_remove_buffers(ctx, bl, p->nbufs);
+	}
+	if (ret < 0)
+		req_set_fail(req);
+
+	/* complete before unlock, IOPOLL may need the lock */
+	__io_req_complete(req, issue_flags, ret, 0);
+	io_ring_submit_unlock(ctx, issue_flags);
+	return 0;
+}
+
+static int io_provide_buffers_prep(struct io_kiocb *req,
+				   const struct io_uring_sqe *sqe)
+{
+	unsigned long size, tmp_check;
+	struct io_provide_buf *p = &req->pbuf;
+	u64 tmp;
+
+	if (sqe->rw_flags || sqe->splice_fd_in)
+		return -EINVAL;
+
+	tmp = READ_ONCE(sqe->fd);
+	if (!tmp || tmp > USHRT_MAX)
+		return -E2BIG;
+	p->nbufs = tmp;
+	p->addr = READ_ONCE(sqe->addr);
+	p->len = READ_ONCE(sqe->len);
+
+	if (check_mul_overflow((unsigned long)p->len, (unsigned long)p->nbufs,
+				&size))
+		return -EOVERFLOW;
+	if (check_add_overflow((unsigned long)p->addr, size, &tmp_check))
+		return -EOVERFLOW;
+
+	size = (unsigned long)p->len * p->nbufs;
+	if (!access_ok(u64_to_user_ptr(p->addr), size))
+		return -EFAULT;
+
+	p->bgid = READ_ONCE(sqe->buf_group);
+	tmp = READ_ONCE(sqe->off);
+	if (tmp > USHRT_MAX)
+		return -E2BIG;
+	p->bid = tmp;
+	return 0;
+}
+
+static int io_refill_buffer_cache(struct io_ring_ctx *ctx)
+{
+	struct io_buffer *buf;
+	struct page *page;
+	int bufs_in_page;
+
+	/*
+	 * Completions that don't happen inline (eg not under uring_lock) will
+	 * add to ->io_buffers_comp. If we don't have any free buffers, check
+	 * the completion list and splice those entries first.
+	 */
+	if (!list_empty_careful(&ctx->io_buffers_comp)) {
+		spin_lock(&ctx->completion_lock);
+		if (!list_empty(&ctx->io_buffers_comp)) {
+			list_splice_init(&ctx->io_buffers_comp,
+						&ctx->io_buffers_cache);
+			spin_unlock(&ctx->completion_lock);
+			return 0;
+		}
+		spin_unlock(&ctx->completion_lock);
+	}
+
+	/*
+	 * No free buffers and no completion entries either. Allocate a new
+	 * page worth of buffer entries and add those to our freelist.
+	 */
+	page = alloc_page(GFP_KERNEL_ACCOUNT);
+	if (!page)
+		return -ENOMEM;
+
+	list_add(&page->lru, &ctx->io_buffers_pages);
+
+	buf = page_address(page);
+	bufs_in_page = PAGE_SIZE / sizeof(*buf);
+	while (bufs_in_page) {
+		list_add_tail(&buf->list, &ctx->io_buffers_cache);
+		buf++;
+		bufs_in_page--;
+	}
+
+	return 0;
+}
+
+static int io_add_buffers(struct io_ring_ctx *ctx, struct io_provide_buf *pbuf,
+			  struct io_buffer_list *bl)
+{
+	struct io_buffer *buf;
+	u64 addr = pbuf->addr;
+	int i, bid = pbuf->bid;
+
+	for (i = 0; i < pbuf->nbufs; i++) {
+		if (list_empty(&ctx->io_buffers_cache) &&
+		    io_refill_buffer_cache(ctx))
+			break;
+		buf = list_first_entry(&ctx->io_buffers_cache, struct io_buffer,
+					list);
+		list_move_tail(&buf->list, &bl->buf_list);
+		buf->addr = addr;
+		buf->len = min_t(__u32, pbuf->len, MAX_RW_COUNT);
+		buf->bid = bid;
+		buf->bgid = pbuf->bgid;
+		addr += pbuf->len;
+		bid++;
+		cond_resched();
+	}
+
+	return i ? 0 : -ENOMEM;
+}
+
+static __cold int io_init_bl_list(struct io_ring_ctx *ctx)
+{
+	int i;
+
+	ctx->io_bl = kcalloc(BGID_ARRAY, sizeof(struct io_buffer_list),
+				GFP_KERNEL);
+	if (!ctx->io_bl)
+		return -ENOMEM;
+
+	for (i = 0; i < BGID_ARRAY; i++) {
+		INIT_LIST_HEAD(&ctx->io_bl[i].buf_list);
+		ctx->io_bl[i].bgid = i;
+	}
+
+	return 0;
+}
+
+static int io_provide_buffers(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_provide_buf *p = &req->pbuf;
+	struct io_ring_ctx *ctx = req->ctx;
+	struct io_buffer_list *bl;
+	int ret = 0;
+
+	io_ring_submit_lock(ctx, issue_flags);
+
+	if (unlikely(p->bgid < BGID_ARRAY && !ctx->io_bl)) {
+		ret = io_init_bl_list(ctx);
+		if (ret)
+			goto err;
+	}
+
+	bl = io_buffer_get_list(ctx, p->bgid);
+	if (unlikely(!bl)) {
+		bl = kzalloc(sizeof(*bl), GFP_KERNEL);
+		if (!bl) {
+			ret = -ENOMEM;
+			goto err;
+		}
+		INIT_LIST_HEAD(&bl->buf_list);
+		ret = io_buffer_add_list(ctx, bl, p->bgid);
+		if (ret) {
+			kfree(bl);
+			goto err;
+		}
+	}
+	/* can't add buffers via this command for a mapped buffer ring */
+	if (bl->buf_nr_pages) {
+		ret = -EINVAL;
+		goto err;
+	}
+
+	ret = io_add_buffers(ctx, p, bl);
+err:
+	if (ret < 0)
+		req_set_fail(req);
+	/* complete before unlock, IOPOLL may need the lock */
+	__io_req_complete(req, issue_flags, ret, 0);
+	io_ring_submit_unlock(ctx, issue_flags);
+	return 0;
+}
+
+static int io_epoll_ctl_prep(struct io_kiocb *req,
+			     const struct io_uring_sqe *sqe)
+{
+#if defined(CONFIG_EPOLL)
+	if (sqe->buf_index || sqe->splice_fd_in)
+		return -EINVAL;
+
+	req->epoll.epfd = READ_ONCE(sqe->fd);
+	req->epoll.op = READ_ONCE(sqe->len);
+	req->epoll.fd = READ_ONCE(sqe->off);
+
+	if (ep_op_has_event(req->epoll.op)) {
+		struct epoll_event __user *ev;
+
+		ev = u64_to_user_ptr(READ_ONCE(sqe->addr));
+		if (copy_from_user(&req->epoll.event, ev, sizeof(*ev)))
+			return -EFAULT;
+	}
+
+	return 0;
+#else
+	return -EOPNOTSUPP;
+#endif
+}
+
+static int io_epoll_ctl(struct io_kiocb *req, unsigned int issue_flags)
+{
+#if defined(CONFIG_EPOLL)
+	struct io_epoll *ie = &req->epoll;
+	int ret;
+	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
+
+	ret = do_epoll_ctl(ie->epfd, ie->op, ie->fd, &ie->event, force_nonblock);
+	if (force_nonblock && ret == -EAGAIN)
+		return -EAGAIN;
+
+	if (ret < 0)
+		req_set_fail(req);
+	__io_req_complete(req, issue_flags, ret, 0);
+	return 0;
+#else
+	return -EOPNOTSUPP;
+#endif
+}
+
+static int io_madvise_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+#if defined(CONFIG_ADVISE_SYSCALLS) && defined(CONFIG_MMU)
+	if (sqe->buf_index || sqe->off || sqe->splice_fd_in)
+		return -EINVAL;
+
+	req->madvise.addr = READ_ONCE(sqe->addr);
+	req->madvise.len = READ_ONCE(sqe->len);
+	req->madvise.advice = READ_ONCE(sqe->fadvise_advice);
+	return 0;
+#else
+	return -EOPNOTSUPP;
+#endif
+}
+
+static int io_madvise(struct io_kiocb *req, unsigned int issue_flags)
+{
+#if defined(CONFIG_ADVISE_SYSCALLS) && defined(CONFIG_MMU)
+	struct io_madvise *ma = &req->madvise;
+	int ret;
+
+	if (issue_flags & IO_URING_F_NONBLOCK)
+		return -EAGAIN;
+
+	ret = do_madvise(current->mm, ma->addr, ma->len, ma->advice);
+	io_req_complete(req, ret);
+	return 0;
+#else
+	return -EOPNOTSUPP;
+#endif
+}
+
+static int io_fadvise_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+	if (sqe->buf_index || sqe->addr || sqe->splice_fd_in)
+		return -EINVAL;
+
+	req->fadvise.offset = READ_ONCE(sqe->off);
+	req->fadvise.len = READ_ONCE(sqe->len);
+	req->fadvise.advice = READ_ONCE(sqe->fadvise_advice);
+	return 0;
+}
+
+static int io_fadvise(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_fadvise *fa = &req->fadvise;
+	int ret;
+
+	if (issue_flags & IO_URING_F_NONBLOCK) {
+		switch (fa->advice) {
+		case POSIX_FADV_NORMAL:
+		case POSIX_FADV_RANDOM:
+		case POSIX_FADV_SEQUENTIAL:
+			break;
+		default:
+			return -EAGAIN;
+		}
+	}
+
+	ret = vfs_fadvise(req->file, fa->offset, fa->len, fa->advice);
+	if (ret < 0)
+		req_set_fail(req);
+	__io_req_complete(req, issue_flags, ret, 0);
+	return 0;
+}
+
+static int io_statx_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+	const char __user *path;
+
+	if (sqe->buf_index || sqe->splice_fd_in)
+		return -EINVAL;
+	if (req->flags & REQ_F_FIXED_FILE)
+		return -EBADF;
+
+	req->statx.dfd = READ_ONCE(sqe->fd);
+	req->statx.mask = READ_ONCE(sqe->len);
+	path = u64_to_user_ptr(READ_ONCE(sqe->addr));
+	req->statx.buffer = u64_to_user_ptr(READ_ONCE(sqe->addr2));
+	req->statx.flags = READ_ONCE(sqe->statx_flags);
+
+	req->statx.filename = getname_flags(path,
+					getname_statx_lookup_flags(req->statx.flags),
+					NULL);
+
+	if (IS_ERR(req->statx.filename)) {
+		int ret = PTR_ERR(req->statx.filename);
+
+		req->statx.filename = NULL;
+		return ret;
+	}
+
+	req->flags |= REQ_F_NEED_CLEANUP;
+	return 0;
+}
+
+static int io_statx(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_statx *ctx = &req->statx;
+	int ret;
+
+	if (issue_flags & IO_URING_F_NONBLOCK)
+		return -EAGAIN;
+
+	ret = do_statx(ctx->dfd, ctx->filename, ctx->flags, ctx->mask,
+		       ctx->buffer);
+	io_req_complete(req, ret);
+	return 0;
+}
+
+static int io_close_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+	if (sqe->off || sqe->addr || sqe->len || sqe->rw_flags || sqe->buf_index)
+		return -EINVAL;
+	if (req->flags & REQ_F_FIXED_FILE)
+		return -EBADF;
+
+	req->close.fd = READ_ONCE(sqe->fd);
+	req->close.file_slot = READ_ONCE(sqe->file_index);
+	if (req->close.file_slot && req->close.fd)
+		return -EINVAL;
+
+	return 0;
+}
+
+static int io_close(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct files_struct *files = current->files;
+	struct io_close *close = &req->close;
+	struct fdtable *fdt;
+	struct file *file;
+	int ret = -EBADF;
+
+	if (req->close.file_slot) {
+		ret = io_close_fixed(req, issue_flags);
+		goto err;
+	}
+
+	spin_lock(&files->file_lock);
+	fdt = files_fdtable(files);
+	if (close->fd >= fdt->max_fds) {
+		spin_unlock(&files->file_lock);
+		goto err;
+	}
+	file = rcu_dereference_protected(fdt->fd[close->fd],
+			lockdep_is_held(&files->file_lock));
+	if (!file || file->f_op == &io_uring_fops) {
+		spin_unlock(&files->file_lock);
+		goto err;
+	}
+
+	/* if the file has a flush method, be safe and punt to async */
+	if (file->f_op->flush && (issue_flags & IO_URING_F_NONBLOCK)) {
+		spin_unlock(&files->file_lock);
+		return -EAGAIN;
+	}
+
+	file = __close_fd_get_file(close->fd);
+	spin_unlock(&files->file_lock);
+	if (!file)
+		goto err;
+
+	/* No ->flush() or already async, safely close from here */
+	ret = filp_close(file, current->files);
+err:
+	if (ret < 0)
+		req_set_fail(req);
+	__io_req_complete(req, issue_flags, ret, 0);
+	return 0;
+}
+
+static int io_sfr_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+	if (unlikely(sqe->addr || sqe->buf_index || sqe->splice_fd_in))
+		return -EINVAL;
+
+	req->sync.off = READ_ONCE(sqe->off);
+	req->sync.len = READ_ONCE(sqe->len);
+	req->sync.flags = READ_ONCE(sqe->sync_range_flags);
+	return 0;
+}
+
+static int io_sync_file_range(struct io_kiocb *req, unsigned int issue_flags)
+{
+	int ret;
+
+	/* sync_file_range always requires a blocking context */
+	if (issue_flags & IO_URING_F_NONBLOCK)
+		return -EAGAIN;
+
+	ret = sync_file_range(req->file, req->sync.off, req->sync.len,
+				req->sync.flags);
+	io_req_complete(req, ret);
+	return 0;
+}
+
+#if defined(CONFIG_NET)
+static int io_shutdown_prep(struct io_kiocb *req,
+			    const struct io_uring_sqe *sqe)
+{
+	if (unlikely(sqe->off || sqe->addr || sqe->rw_flags ||
+		     sqe->buf_index || sqe->splice_fd_in))
+		return -EINVAL;
+
+	req->shutdown.how = READ_ONCE(sqe->len);
+	return 0;
+}
+
+static int io_shutdown(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct socket *sock;
+	int ret;
+
+	if (issue_flags & IO_URING_F_NONBLOCK)
+		return -EAGAIN;
+
+	sock = sock_from_file(req->file);
+	if (unlikely(!sock))
+		return -ENOTSOCK;
+
+	ret = __sys_shutdown_sock(sock, req->shutdown.how);
+	io_req_complete(req, ret);
+	return 0;
+}
+
+static bool io_net_retry(struct socket *sock, int flags)
+{
+	if (!(flags & MSG_WAITALL))
+		return false;
+	return sock->type == SOCK_STREAM || sock->type == SOCK_SEQPACKET;
+}
+
+static int io_setup_async_msg(struct io_kiocb *req,
+			      struct io_async_msghdr *kmsg)
+{
+	struct io_async_msghdr *async_msg = req->async_data;
+
+	if (async_msg)
+		return -EAGAIN;
+	if (io_alloc_async_data(req)) {
+		kfree(kmsg->free_iov);
+		return -ENOMEM;
+	}
+	async_msg = req->async_data;
+	req->flags |= REQ_F_NEED_CLEANUP;
+	memcpy(async_msg, kmsg, sizeof(*kmsg));
+	async_msg->msg.msg_name = &async_msg->addr;
+	/* if were using fast_iov, set it to the new one */
+	if (!async_msg->free_iov)
+		async_msg->msg.msg_iter.iov = async_msg->fast_iov;
+
+	return -EAGAIN;
+}
+
+static int io_sendmsg_copy_hdr(struct io_kiocb *req,
+			       struct io_async_msghdr *iomsg)
+{
+	iomsg->msg.msg_name = &iomsg->addr;
+	iomsg->free_iov = iomsg->fast_iov;
+	return sendmsg_copy_msghdr(&iomsg->msg, req->sr_msg.umsg,
+				   req->sr_msg.msg_flags, &iomsg->free_iov);
+}
+
+static int io_sendmsg_prep_async(struct io_kiocb *req)
+{
+	int ret;
+
+	ret = io_sendmsg_copy_hdr(req, req->async_data);
+	if (!ret)
+		req->flags |= REQ_F_NEED_CLEANUP;
+	return ret;
+}
+
+static int io_sendmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+	struct io_sr_msg *sr = &req->sr_msg;
+
+	if (unlikely(sqe->file_index || sqe->addr2))
+		return -EINVAL;
+
+	sr->umsg = u64_to_user_ptr(READ_ONCE(sqe->addr));
+	sr->len = READ_ONCE(sqe->len);
+	sr->flags = READ_ONCE(sqe->ioprio);
+	if (sr->flags & ~IORING_RECVSEND_POLL_FIRST)
+		return -EINVAL;
+	sr->msg_flags = READ_ONCE(sqe->msg_flags) | MSG_NOSIGNAL;
+	if (sr->msg_flags & MSG_DONTWAIT)
+		req->flags |= REQ_F_NOWAIT;
+
+#ifdef CONFIG_COMPAT
+	if (req->ctx->compat)
+		sr->msg_flags |= MSG_CMSG_COMPAT;
+#endif
+	sr->done_io = 0;
+	return 0;
+}
+
+static int io_sendmsg(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_async_msghdr iomsg, *kmsg;
+	struct io_sr_msg *sr = &req->sr_msg;
+	struct socket *sock;
+	unsigned flags;
+	int min_ret = 0;
+	int ret;
+
+	sock = sock_from_file(req->file);
+	if (unlikely(!sock))
+		return -ENOTSOCK;
+
+	if (req_has_async_data(req)) {
+		kmsg = req->async_data;
+	} else {
+		ret = io_sendmsg_copy_hdr(req, &iomsg);
+		if (ret)
+			return ret;
+		kmsg = &iomsg;
+	}
+
+	if (!(req->flags & REQ_F_POLLED) &&
+	    (sr->flags & IORING_RECVSEND_POLL_FIRST))
+		return io_setup_async_msg(req, kmsg);
+
+	flags = sr->msg_flags;
+	if (issue_flags & IO_URING_F_NONBLOCK)
+		flags |= MSG_DONTWAIT;
+	if (flags & MSG_WAITALL)
+		min_ret = iov_iter_count(&kmsg->msg.msg_iter);
+
+	ret = __sys_sendmsg_sock(sock, &kmsg->msg, flags);
+
+	if (ret < min_ret) {
+		if (ret == -EAGAIN && (issue_flags & IO_URING_F_NONBLOCK))
+			return io_setup_async_msg(req, kmsg);
+		if (ret == -ERESTARTSYS)
+			ret = -EINTR;
+		if (ret > 0 && io_net_retry(sock, flags)) {
+			sr->done_io += ret;
+			req->flags |= REQ_F_PARTIAL_IO;
+			return io_setup_async_msg(req, kmsg);
+		}
+		req_set_fail(req);
+	}
+	/* fast path, check for non-NULL to avoid function call */
+	if (kmsg->free_iov)
+		kfree(kmsg->free_iov);
+	req->flags &= ~REQ_F_NEED_CLEANUP;
+	if (ret >= 0)
+		ret += sr->done_io;
+	else if (sr->done_io)
+		ret = sr->done_io;
+	__io_req_complete(req, issue_flags, ret, 0);
+	return 0;
+}
+
+static int io_send(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_sr_msg *sr = &req->sr_msg;
+	struct msghdr msg;
+	struct iovec iov;
+	struct socket *sock;
+	unsigned flags;
+	int min_ret = 0;
+	int ret;
+
+	if (!(req->flags & REQ_F_POLLED) &&
+	    (sr->flags & IORING_RECVSEND_POLL_FIRST))
+		return -EAGAIN;
+
+	sock = sock_from_file(req->file);
+	if (unlikely(!sock))
+		return -ENOTSOCK;
+
+	ret = import_single_range(WRITE, sr->buf, sr->len, &iov, &msg.msg_iter);
+	if (unlikely(ret))
+		return ret;
+
+	msg.msg_name = NULL;
+	msg.msg_control = NULL;
+	msg.msg_controllen = 0;
+	msg.msg_namelen = 0;
+
+	flags = sr->msg_flags;
+	if (issue_flags & IO_URING_F_NONBLOCK)
+		flags |= MSG_DONTWAIT;
+	if (flags & MSG_WAITALL)
+		min_ret = iov_iter_count(&msg.msg_iter);
+
+	msg.msg_flags = flags;
+	ret = sock_sendmsg(sock, &msg);
+	if (ret < min_ret) {
+		if (ret == -EAGAIN && (issue_flags & IO_URING_F_NONBLOCK))
+			return -EAGAIN;
+		if (ret == -ERESTARTSYS)
+			ret = -EINTR;
+		if (ret > 0 && io_net_retry(sock, flags)) {
+			sr->len -= ret;
+			sr->buf += ret;
+			sr->done_io += ret;
+			req->flags |= REQ_F_PARTIAL_IO;
+			return -EAGAIN;
+		}
+		req_set_fail(req);
+	}
+	if (ret >= 0)
+		ret += sr->done_io;
+	else if (sr->done_io)
+		ret = sr->done_io;
+	__io_req_complete(req, issue_flags, ret, 0);
+	return 0;
+}
+
+static int __io_recvmsg_copy_hdr(struct io_kiocb *req,
+				 struct io_async_msghdr *iomsg)
+{
+	struct io_sr_msg *sr = &req->sr_msg;
+	struct iovec __user *uiov;
+	size_t iov_len;
+	int ret;
+
+	ret = __copy_msghdr_from_user(&iomsg->msg, sr->umsg,
+					&iomsg->uaddr, &uiov, &iov_len);
+	if (ret)
+		return ret;
+
+	if (req->flags & REQ_F_BUFFER_SELECT) {
+		if (iov_len > 1)
+			return -EINVAL;
+		if (copy_from_user(iomsg->fast_iov, uiov, sizeof(*uiov)))
+			return -EFAULT;
+		sr->len = iomsg->fast_iov[0].iov_len;
+		iomsg->free_iov = NULL;
+	} else {
+		iomsg->free_iov = iomsg->fast_iov;
+		ret = __import_iovec(READ, uiov, iov_len, UIO_FASTIOV,
+				     &iomsg->free_iov, &iomsg->msg.msg_iter,
+				     false);
+		if (ret > 0)
+			ret = 0;
+	}
+
+	return ret;
+}
+
+#ifdef CONFIG_COMPAT
+static int __io_compat_recvmsg_copy_hdr(struct io_kiocb *req,
+					struct io_async_msghdr *iomsg)
+{
+	struct io_sr_msg *sr = &req->sr_msg;
+	struct compat_iovec __user *uiov;
+	compat_uptr_t ptr;
+	compat_size_t len;
+	int ret;
+
+	ret = __get_compat_msghdr(&iomsg->msg, sr->umsg_compat, &iomsg->uaddr,
+				  &ptr, &len);
+	if (ret)
+		return ret;
+
+	uiov = compat_ptr(ptr);
+	if (req->flags & REQ_F_BUFFER_SELECT) {
+		compat_ssize_t clen;
+
+		if (len > 1)
+			return -EINVAL;
+		if (!access_ok(uiov, sizeof(*uiov)))
+			return -EFAULT;
+		if (__get_user(clen, &uiov->iov_len))
+			return -EFAULT;
+		if (clen < 0)
+			return -EINVAL;
+		sr->len = clen;
+		iomsg->free_iov = NULL;
+	} else {
+		iomsg->free_iov = iomsg->fast_iov;
+		ret = __import_iovec(READ, (struct iovec __user *)uiov, len,
+				   UIO_FASTIOV, &iomsg->free_iov,
+				   &iomsg->msg.msg_iter, true);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+#endif
+
+static int io_recvmsg_copy_hdr(struct io_kiocb *req,
+			       struct io_async_msghdr *iomsg)
+{
+	iomsg->msg.msg_name = &iomsg->addr;
+
+#ifdef CONFIG_COMPAT
+	if (req->ctx->compat)
+		return __io_compat_recvmsg_copy_hdr(req, iomsg);
+#endif
+
+	return __io_recvmsg_copy_hdr(req, iomsg);
+}
+
+static int io_recvmsg_prep_async(struct io_kiocb *req)
+{
+	int ret;
+
+	ret = io_recvmsg_copy_hdr(req, req->async_data);
+	if (!ret)
+		req->flags |= REQ_F_NEED_CLEANUP;
+	return ret;
+}
+
+static int io_recvmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+	struct io_sr_msg *sr = &req->sr_msg;
+
+	if (unlikely(sqe->file_index || sqe->addr2))
+		return -EINVAL;
+
+	sr->umsg = u64_to_user_ptr(READ_ONCE(sqe->addr));
+	sr->len = READ_ONCE(sqe->len);
+	sr->flags = READ_ONCE(sqe->ioprio);
+	if (sr->flags & ~IORING_RECVSEND_POLL_FIRST)
+		return -EINVAL;
+	sr->msg_flags = READ_ONCE(sqe->msg_flags) | MSG_NOSIGNAL;
+	if (sr->msg_flags & MSG_DONTWAIT)
+		req->flags |= REQ_F_NOWAIT;
+
+#ifdef CONFIG_COMPAT
+	if (req->ctx->compat)
+		sr->msg_flags |= MSG_CMSG_COMPAT;
+#endif
+	sr->done_io = 0;
+	return 0;
+}
+
+static int io_recvmsg(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_async_msghdr iomsg, *kmsg;
+	struct io_sr_msg *sr = &req->sr_msg;
+	struct socket *sock;
+	unsigned int cflags;
+	unsigned flags;
+	int ret, min_ret = 0;
+	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
+
+	sock = sock_from_file(req->file);
+	if (unlikely(!sock))
+		return -ENOTSOCK;
+
+	if (req_has_async_data(req)) {
+		kmsg = req->async_data;
+	} else {
+		ret = io_recvmsg_copy_hdr(req, &iomsg);
+		if (ret)
+			return ret;
+		kmsg = &iomsg;
+	}
+
+	if (!(req->flags & REQ_F_POLLED) &&
+	    (sr->flags & IORING_RECVSEND_POLL_FIRST))
+		return io_setup_async_msg(req, kmsg);
+
+	if (io_do_buffer_select(req)) {
+		void __user *buf;
+
+		buf = io_buffer_select(req, &sr->len, issue_flags);
+		if (!buf)
+			return -ENOBUFS;
+		kmsg->fast_iov[0].iov_base = buf;
+		kmsg->fast_iov[0].iov_len = sr->len;
+		iov_iter_init(&kmsg->msg.msg_iter, READ, kmsg->fast_iov, 1,
+				sr->len);
+	}
+
+	flags = sr->msg_flags;
+	if (force_nonblock)
+		flags |= MSG_DONTWAIT;
+	if (flags & MSG_WAITALL)
+		min_ret = iov_iter_count(&kmsg->msg.msg_iter);
+
+	kmsg->msg.msg_get_inq = 1;
+	ret = __sys_recvmsg_sock(sock, &kmsg->msg, sr->umsg, kmsg->uaddr, flags);
+	if (ret < min_ret) {
+		if (ret == -EAGAIN && force_nonblock)
+			return io_setup_async_msg(req, kmsg);
+		if (ret == -ERESTARTSYS)
+			ret = -EINTR;
+		if (ret > 0 && io_net_retry(sock, flags)) {
+			sr->done_io += ret;
+			req->flags |= REQ_F_PARTIAL_IO;
+			return io_setup_async_msg(req, kmsg);
+		}
+		req_set_fail(req);
+	} else if ((flags & MSG_WAITALL) && (kmsg->msg.msg_flags & (MSG_TRUNC | MSG_CTRUNC))) {
+		req_set_fail(req);
+	}
+
+	/* fast path, check for non-NULL to avoid function call */
+	if (kmsg->free_iov)
+		kfree(kmsg->free_iov);
+	req->flags &= ~REQ_F_NEED_CLEANUP;
+	if (ret >= 0)
+		ret += sr->done_io;
+	else if (sr->done_io)
+		ret = sr->done_io;
+	cflags = io_put_kbuf(req, issue_flags);
+	if (kmsg->msg.msg_inq)
+		cflags |= IORING_CQE_F_SOCK_NONEMPTY;
+	__io_req_complete(req, issue_flags, ret, cflags);
+	return 0;
+}
+
+static int io_recv(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_sr_msg *sr = &req->sr_msg;
+	struct msghdr msg;
+	struct socket *sock;
+	struct iovec iov;
+	unsigned int cflags;
+	unsigned flags;
+	int ret, min_ret = 0;
+	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
+
+	if (!(req->flags & REQ_F_POLLED) &&
+	    (sr->flags & IORING_RECVSEND_POLL_FIRST))
+		return -EAGAIN;
+
+	sock = sock_from_file(req->file);
+	if (unlikely(!sock))
+		return -ENOTSOCK;
+
+	if (io_do_buffer_select(req)) {
+		void __user *buf;
+
+		buf = io_buffer_select(req, &sr->len, issue_flags);
+		if (!buf)
+			return -ENOBUFS;
+		sr->buf = buf;
+	}
+
+	ret = import_single_range(READ, sr->buf, sr->len, &iov, &msg.msg_iter);
+	if (unlikely(ret))
+		goto out_free;
+
+	msg.msg_name = NULL;
+	msg.msg_namelen = 0;
+	msg.msg_control = NULL;
+	msg.msg_get_inq = 1;
+	msg.msg_flags = 0;
+	msg.msg_controllen = 0;
+	msg.msg_iocb = NULL;
+
+	flags = sr->msg_flags;
+	if (force_nonblock)
+		flags |= MSG_DONTWAIT;
+	if (flags & MSG_WAITALL)
+		min_ret = iov_iter_count(&msg.msg_iter);
+
+	ret = sock_recvmsg(sock, &msg, flags);
+	if (ret < min_ret) {
+		if (ret == -EAGAIN && force_nonblock)
+			return -EAGAIN;
+		if (ret == -ERESTARTSYS)
+			ret = -EINTR;
+		if (ret > 0 && io_net_retry(sock, flags)) {
+			sr->len -= ret;
+			sr->buf += ret;
+			sr->done_io += ret;
+			req->flags |= REQ_F_PARTIAL_IO;
+			return -EAGAIN;
+		}
+		req_set_fail(req);
+	} else if ((flags & MSG_WAITALL) && (msg.msg_flags & (MSG_TRUNC | MSG_CTRUNC))) {
+out_free:
+		req_set_fail(req);
+	}
+
+	if (ret >= 0)
+		ret += sr->done_io;
+	else if (sr->done_io)
+		ret = sr->done_io;
+	cflags = io_put_kbuf(req, issue_flags);
+	if (msg.msg_inq)
+		cflags |= IORING_CQE_F_SOCK_NONEMPTY;
+	__io_req_complete(req, issue_flags, ret, cflags);
+	return 0;
+}
+
+static int io_accept_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+	struct io_accept *accept = &req->accept;
+	unsigned flags;
+
+	if (sqe->len || sqe->buf_index)
+		return -EINVAL;
+
+	accept->addr = u64_to_user_ptr(READ_ONCE(sqe->addr));
+	accept->addr_len = u64_to_user_ptr(READ_ONCE(sqe->addr2));
+	accept->flags = READ_ONCE(sqe->accept_flags);
+	accept->nofile = rlimit(RLIMIT_NOFILE);
+	flags = READ_ONCE(sqe->ioprio);
+	if (flags & ~IORING_ACCEPT_MULTISHOT)
+		return -EINVAL;
+
+	accept->file_slot = READ_ONCE(sqe->file_index);
+	if (accept->file_slot) {
+		if (accept->flags & SOCK_CLOEXEC)
+			return -EINVAL;
+		if (flags & IORING_ACCEPT_MULTISHOT &&
+		    accept->file_slot != IORING_FILE_INDEX_ALLOC)
+			return -EINVAL;
+	}
+	if (accept->flags & ~(SOCK_CLOEXEC | SOCK_NONBLOCK))
+		return -EINVAL;
+	if (SOCK_NONBLOCK != O_NONBLOCK && (accept->flags & SOCK_NONBLOCK))
+		accept->flags = (accept->flags & ~SOCK_NONBLOCK) | O_NONBLOCK;
+	if (flags & IORING_ACCEPT_MULTISHOT)
+		req->flags |= REQ_F_APOLL_MULTISHOT;
+	return 0;
+}
+
+static int io_accept(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_ring_ctx *ctx = req->ctx;
+	struct io_accept *accept = &req->accept;
+	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
+	unsigned int file_flags = force_nonblock ? O_NONBLOCK : 0;
+	bool fixed = !!accept->file_slot;
+	struct file *file;
+	int ret, fd;
+
+retry:
+	if (!fixed) {
+		fd = __get_unused_fd_flags(accept->flags, accept->nofile);
+		if (unlikely(fd < 0))
+			return fd;
+	}
+	file = do_accept(req->file, file_flags, accept->addr, accept->addr_len,
+			 accept->flags);
+	if (IS_ERR(file)) {
+		if (!fixed)
+			put_unused_fd(fd);
+		ret = PTR_ERR(file);
+		if (ret == -EAGAIN && force_nonblock) {
+			/*
+			 * if it's multishot and polled, we don't need to
+			 * return EAGAIN to arm the poll infra since it
+			 * has already been done
+			 */
+			if ((req->flags & IO_APOLL_MULTI_POLLED) ==
+			    IO_APOLL_MULTI_POLLED)
+				ret = 0;
+			return ret;
+		}
+		if (ret == -ERESTARTSYS)
+			ret = -EINTR;
+		req_set_fail(req);
+	} else if (!fixed) {
+		fd_install(fd, file);
+		ret = fd;
+	} else {
+		ret = io_fixed_fd_install(req, issue_flags, file,
+						accept->file_slot);
+	}
+
+	if (!(req->flags & REQ_F_APOLL_MULTISHOT)) {
+		__io_req_complete(req, issue_flags, ret, 0);
+		return 0;
+	}
+	if (ret >= 0) {
+		bool filled;
+
+		spin_lock(&ctx->completion_lock);
+		filled = io_fill_cqe_aux(ctx, req->cqe.user_data, ret,
+					 IORING_CQE_F_MORE);
+		io_commit_cqring(ctx);
+		spin_unlock(&ctx->completion_lock);
+		if (filled) {
+			io_cqring_ev_posted(ctx);
+			goto retry;
+		}
+		ret = -ECANCELED;
+	}
+
+	return ret;
+}
+
+static int io_socket_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+	struct io_socket *sock = &req->sock;
+
+	if (sqe->addr || sqe->rw_flags || sqe->buf_index)
+		return -EINVAL;
+
+	sock->domain = READ_ONCE(sqe->fd);
+	sock->type = READ_ONCE(sqe->off);
+	sock->protocol = READ_ONCE(sqe->len);
+	sock->file_slot = READ_ONCE(sqe->file_index);
+	sock->nofile = rlimit(RLIMIT_NOFILE);
+
+	sock->flags = sock->type & ~SOCK_TYPE_MASK;
+	if (sock->file_slot && (sock->flags & SOCK_CLOEXEC))
+		return -EINVAL;
+	if (sock->flags & ~(SOCK_CLOEXEC | SOCK_NONBLOCK))
+		return -EINVAL;
+	return 0;
+}
+
+static int io_socket(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_socket *sock = &req->sock;
+	bool fixed = !!sock->file_slot;
+	struct file *file;
+	int ret, fd;
+
+	if (!fixed) {
+		fd = __get_unused_fd_flags(sock->flags, sock->nofile);
+		if (unlikely(fd < 0))
+			return fd;
+	}
+	file = __sys_socket_file(sock->domain, sock->type, sock->protocol);
+	if (IS_ERR(file)) {
+		if (!fixed)
+			put_unused_fd(fd);
+		ret = PTR_ERR(file);
+		if (ret == -EAGAIN && (issue_flags & IO_URING_F_NONBLOCK))
+			return -EAGAIN;
+		if (ret == -ERESTARTSYS)
+			ret = -EINTR;
+		req_set_fail(req);
+	} else if (!fixed) {
+		fd_install(fd, file);
+		ret = fd;
+	} else {
+		ret = io_fixed_fd_install(req, issue_flags, file,
+					    sock->file_slot);
+	}
+	__io_req_complete(req, issue_flags, ret, 0);
+	return 0;
+}
+
+static int io_connect_prep_async(struct io_kiocb *req)
+{
+	struct io_async_connect *io = req->async_data;
+	struct io_connect *conn = &req->connect;
+
+	return move_addr_to_kernel(conn->addr, conn->addr_len, &io->address);
+}
+
+static int io_connect_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+	struct io_connect *conn = &req->connect;
+
+	if (sqe->len || sqe->buf_index || sqe->rw_flags || sqe->splice_fd_in)
+		return -EINVAL;
+
+	conn->addr = u64_to_user_ptr(READ_ONCE(sqe->addr));
+	conn->addr_len =  READ_ONCE(sqe->addr2);
+	return 0;
+}
+
+static int io_connect(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_async_connect __io, *io;
+	unsigned file_flags;
+	int ret;
+	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
+
+	if (req_has_async_data(req)) {
+		io = req->async_data;
+	} else {
+		ret = move_addr_to_kernel(req->connect.addr,
+						req->connect.addr_len,
+						&__io.address);
+		if (ret)
+			goto out;
+		io = &__io;
+	}
+
+	file_flags = force_nonblock ? O_NONBLOCK : 0;
+
+	ret = __sys_connect_file(req->file, &io->address,
+					req->connect.addr_len, file_flags);
+	if ((ret == -EAGAIN || ret == -EINPROGRESS) && force_nonblock) {
+		if (req_has_async_data(req))
+			return -EAGAIN;
+		if (io_alloc_async_data(req)) {
+			ret = -ENOMEM;
+			goto out;
+		}
+		memcpy(req->async_data, &__io, sizeof(__io));
+		return -EAGAIN;
+	}
+	if (ret == -ERESTARTSYS)
+		ret = -EINTR;
+out:
+	if (ret < 0)
+		req_set_fail(req);
+	__io_req_complete(req, issue_flags, ret, 0);
+	return 0;
+}
+#else /* !CONFIG_NET */
+#define IO_NETOP_FN(op)							\
+static int io_##op(struct io_kiocb *req, unsigned int issue_flags)	\
+{									\
+	return -EOPNOTSUPP;						\
+}
+
+#define IO_NETOP_PREP(op)						\
+IO_NETOP_FN(op)								\
+static int io_##op##_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) \
+{									\
+	return -EOPNOTSUPP;						\
+}									\
+
+#define IO_NETOP_PREP_ASYNC(op)						\
+IO_NETOP_PREP(op)							\
+static int io_##op##_prep_async(struct io_kiocb *req)			\
+{									\
+	return -EOPNOTSUPP;						\
+}
+
+IO_NETOP_PREP_ASYNC(sendmsg);
+IO_NETOP_PREP_ASYNC(recvmsg);
+IO_NETOP_PREP_ASYNC(connect);
+IO_NETOP_PREP(accept);
+IO_NETOP_PREP(socket);
+IO_NETOP_PREP(shutdown);
+IO_NETOP_FN(send);
+IO_NETOP_FN(recv);
+#endif /* CONFIG_NET */
+
+struct io_poll_table {
+	struct poll_table_struct pt;
+	struct io_kiocb *req;
+	int nr_entries;
+	int error;
+};
+
+#define IO_POLL_CANCEL_FLAG	BIT(31)
+#define IO_POLL_REF_MASK	GENMASK(30, 0)
+
+/*
+ * If refs part of ->poll_refs (see IO_POLL_REF_MASK) is 0, it's free. We can
+ * bump it and acquire ownership. It's disallowed to modify requests while not
+ * owning it, that prevents from races for enqueueing task_work's and b/w
+ * arming poll and wakeups.
+ */
+static inline bool io_poll_get_ownership(struct io_kiocb *req)
+{
+	return !(atomic_fetch_inc(&req->poll_refs) & IO_POLL_REF_MASK);
+}
+
+static void io_poll_mark_cancelled(struct io_kiocb *req)
+{
+	atomic_or(IO_POLL_CANCEL_FLAG, &req->poll_refs);
+}
+
+static struct io_poll_iocb *io_poll_get_double(struct io_kiocb *req)
+{
+	/* pure poll stashes this in ->async_data, poll driven retry elsewhere */
+	if (req->opcode == IORING_OP_POLL_ADD)
+		return req->async_data;
+	return req->apoll->double_poll;
+}
+
+static struct io_poll_iocb *io_poll_get_single(struct io_kiocb *req)
+{
+	if (req->opcode == IORING_OP_POLL_ADD)
+		return &req->poll;
+	return &req->apoll->poll;
+}
+
+static void io_poll_req_insert(struct io_kiocb *req)
+{
+	struct io_ring_ctx *ctx = req->ctx;
+	struct hlist_head *list;
+
+	list = &ctx->cancel_hash[hash_long(req->cqe.user_data, ctx->cancel_hash_bits)];
+	hlist_add_head(&req->hash_node, list);
+}
+
+static void io_init_poll_iocb(struct io_poll_iocb *poll, __poll_t events,
+			      wait_queue_func_t wake_func)
+{
+	poll->head = NULL;
+#define IO_POLL_UNMASK	(EPOLLERR|EPOLLHUP|EPOLLNVAL|EPOLLRDHUP)
+	/* mask in events that we always want/need */
+	poll->events = events | IO_POLL_UNMASK;
+	INIT_LIST_HEAD(&poll->wait.entry);
+	init_waitqueue_func_entry(&poll->wait, wake_func);
+}
+
+static inline void io_poll_remove_entry(struct io_poll_iocb *poll)
+{
+	struct wait_queue_head *head = smp_load_acquire(&poll->head);
+
+	if (head) {
+		spin_lock_irq(&head->lock);
+		list_del_init(&poll->wait.entry);
+		poll->head = NULL;
+		spin_unlock_irq(&head->lock);
+	}
+}
+
+static void io_poll_remove_entries(struct io_kiocb *req)
+{
+	/*
+	 * Nothing to do if neither of those flags are set. Avoid dipping
+	 * into the poll/apoll/double cachelines if we can.
+	 */
+	if (!(req->flags & (REQ_F_SINGLE_POLL | REQ_F_DOUBLE_POLL)))
+		return;
+
+	/*
+	 * While we hold the waitqueue lock and the waitqueue is nonempty,
+	 * wake_up_pollfree() will wait for us.  However, taking the waitqueue
+	 * lock in the first place can race with the waitqueue being freed.
+	 *
+	 * We solve this as eventpoll does: by taking advantage of the fact that
+	 * all users of wake_up_pollfree() will RCU-delay the actual free.  If
+	 * we enter rcu_read_lock() and see that the pointer to the queue is
+	 * non-NULL, we can then lock it without the memory being freed out from
+	 * under us.
+	 *
+	 * Keep holding rcu_read_lock() as long as we hold the queue lock, in
+	 * case the caller deletes the entry from the queue, leaving it empty.
+	 * In that case, only RCU prevents the queue memory from being freed.
+	 */
+	rcu_read_lock();
+	if (req->flags & REQ_F_SINGLE_POLL)
+		io_poll_remove_entry(io_poll_get_single(req));
+	if (req->flags & REQ_F_DOUBLE_POLL)
+		io_poll_remove_entry(io_poll_get_double(req));
+	rcu_read_unlock();
+}
+
+static int io_issue_sqe(struct io_kiocb *req, unsigned int issue_flags);
+/*
+ * All poll tw should go through this. Checks for poll events, manages
+ * references, does rewait, etc.
+ *
+ * Returns a negative error on failure. >0 when no action require, which is
+ * either spurious wakeup or multishot CQE is served. 0 when it's done with
+ * the request, then the mask is stored in req->cqe.res.
+ */
+static int io_poll_check_events(struct io_kiocb *req, bool *locked)
+{
+	struct io_ring_ctx *ctx = req->ctx;
+	int v, ret;
+
+	/* req->task == current here, checking PF_EXITING is safe */
+	if (unlikely(req->task->flags & PF_EXITING))
+		return -ECANCELED;
+
+	do {
+		v = atomic_read(&req->poll_refs);
+
+		/* tw handler should be the owner, and so have some references */
+		if (WARN_ON_ONCE(!(v & IO_POLL_REF_MASK)))
+			return 0;
+		if (v & IO_POLL_CANCEL_FLAG)
+			return -ECANCELED;
+
+		if (!req->cqe.res) {
+			struct poll_table_struct pt = { ._key = req->apoll_events };
+			req->cqe.res = vfs_poll(req->file, &pt) & req->apoll_events;
+		}
+
+		if ((unlikely(!req->cqe.res)))
+			continue;
+		if (req->apoll_events & EPOLLONESHOT)
+			return 0;
+
+		/* multishot, just fill a CQE and proceed */
+		if (!(req->flags & REQ_F_APOLL_MULTISHOT)) {
+			__poll_t mask = mangle_poll(req->cqe.res &
+						    req->apoll_events);
+			bool filled;
+
+			spin_lock(&ctx->completion_lock);
+			filled = io_fill_cqe_aux(ctx, req->cqe.user_data,
+						 mask, IORING_CQE_F_MORE);
+			io_commit_cqring(ctx);
+			spin_unlock(&ctx->completion_lock);
+			if (filled) {
+				io_cqring_ev_posted(ctx);
+				continue;
+			}
+			return -ECANCELED;
+		}
+
+		io_tw_lock(req->ctx, locked);
+		if (unlikely(req->task->flags & PF_EXITING))
+			return -EFAULT;
+		ret = io_issue_sqe(req,
+				   IO_URING_F_NONBLOCK|IO_URING_F_COMPLETE_DEFER);
+		if (ret)
+			return ret;
+
+		/*
+		 * Release all references, retry if someone tried to restart
+		 * task_work while we were executing it.
+		 */
+	} while (atomic_sub_return(v & IO_POLL_REF_MASK, &req->poll_refs));
+
+	return 1;
+}
+
+static void io_poll_task_func(struct io_kiocb *req, bool *locked)
+{
+	struct io_ring_ctx *ctx = req->ctx;
+	int ret;
+
+	ret = io_poll_check_events(req, locked);
+	if (ret > 0)
+		return;
+
+	if (!ret) {
+		req->cqe.res = mangle_poll(req->cqe.res & req->poll.events);
+	} else {
+		req->cqe.res = ret;
+		req_set_fail(req);
+	}
+
+	io_poll_remove_entries(req);
+	spin_lock(&ctx->completion_lock);
+	hash_del(&req->hash_node);
+	__io_req_complete_post(req, req->cqe.res, 0);
+	io_commit_cqring(ctx);
+	spin_unlock(&ctx->completion_lock);
+	io_cqring_ev_posted(ctx);
+}
+
+static void io_apoll_task_func(struct io_kiocb *req, bool *locked)
+{
+	struct io_ring_ctx *ctx = req->ctx;
+	int ret;
+
+	ret = io_poll_check_events(req, locked);
+	if (ret > 0)
+		return;
+
+	io_poll_remove_entries(req);
+	spin_lock(&ctx->completion_lock);
+	hash_del(&req->hash_node);
+	spin_unlock(&ctx->completion_lock);
+
+	if (!ret)
+		io_req_task_submit(req, locked);
+	else
+		io_req_complete_failed(req, ret);
+}
+
+static void __io_poll_execute(struct io_kiocb *req, int mask,
+			      __poll_t __maybe_unused events)
+{
+	req->cqe.res = mask;
+	/*
+	 * This is useful for poll that is armed on behalf of another
+	 * request, and where the wakeup path could be on a different
+	 * CPU. We want to avoid pulling in req->apoll->events for that
+	 * case.
+	 */
+	if (req->opcode == IORING_OP_POLL_ADD)
+		req->io_task_work.func = io_poll_task_func;
+	else
+		req->io_task_work.func = io_apoll_task_func;
+
+	trace_io_uring_task_add(req->ctx, req, req->cqe.user_data, req->opcode, mask);
+	io_req_task_work_add(req);
+}
+
+static inline void io_poll_execute(struct io_kiocb *req, int res,
+		__poll_t events)
+{
+	if (io_poll_get_ownership(req))
+		__io_poll_execute(req, res, events);
+}
+
+static void io_poll_cancel_req(struct io_kiocb *req)
+{
+	io_poll_mark_cancelled(req);
+	/* kick tw, which should complete the request */
+	io_poll_execute(req, 0, 0);
+}
+
+#define wqe_to_req(wait)	((void *)((unsigned long) (wait)->private & ~1))
+#define wqe_is_double(wait)	((unsigned long) (wait)->private & 1)
+#define IO_ASYNC_POLL_COMMON	(EPOLLONESHOT | EPOLLPRI)
+
+static int io_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync,
+			void *key)
+{
+	struct io_kiocb *req = wqe_to_req(wait);
+	struct io_poll_iocb *poll = container_of(wait, struct io_poll_iocb,
+						 wait);
+	__poll_t mask = key_to_poll(key);
+
+	if (unlikely(mask & POLLFREE)) {
+		io_poll_mark_cancelled(req);
+		/* we have to kick tw in case it's not already */
+		io_poll_execute(req, 0, poll->events);
+
+		/*
+		 * If the waitqueue is being freed early but someone is already
+		 * holds ownership over it, we have to tear down the request as
+		 * best we can. That means immediately removing the request from
+		 * its waitqueue and preventing all further accesses to the
+		 * waitqueue via the request.
+		 */
+		list_del_init(&poll->wait.entry);
+
+		/*
+		 * Careful: this *must* be the last step, since as soon
+		 * as req->head is NULL'ed out, the request can be
+		 * completed and freed, since aio_poll_complete_work()
+		 * will no longer need to take the waitqueue lock.
+		 */
+		smp_store_release(&poll->head, NULL);
+		return 1;
+	}
+
+	/* for instances that support it check for an event match first */
+	if (mask && !(mask & (poll->events & ~IO_ASYNC_POLL_COMMON)))
+		return 0;
+
+	if (io_poll_get_ownership(req)) {
+		/* optional, saves extra locking for removal in tw handler */
+		if (mask && poll->events & EPOLLONESHOT) {
+			list_del_init(&poll->wait.entry);
+			poll->head = NULL;
+			if (wqe_is_double(wait))
+				req->flags &= ~REQ_F_DOUBLE_POLL;
+			else
+				req->flags &= ~REQ_F_SINGLE_POLL;
+		}
+		__io_poll_execute(req, mask, poll->events);
+	}
+	return 1;
+}
+
+static void __io_queue_proc(struct io_poll_iocb *poll, struct io_poll_table *pt,
+			    struct wait_queue_head *head,
+			    struct io_poll_iocb **poll_ptr)
+{
+	struct io_kiocb *req = pt->req;
+	unsigned long wqe_private = (unsigned long) req;
+
+	/*
+	 * The file being polled uses multiple waitqueues for poll handling
+	 * (e.g. one for read, one for write). Setup a separate io_poll_iocb
+	 * if this happens.
+	 */
+	if (unlikely(pt->nr_entries)) {
+		struct io_poll_iocb *first = poll;
+
+		/* double add on the same waitqueue head, ignore */
+		if (first->head == head)
+			return;
+		/* already have a 2nd entry, fail a third attempt */
+		if (*poll_ptr) {
+			if ((*poll_ptr)->head == head)
+				return;
+			pt->error = -EINVAL;
+			return;
+		}
+
+		poll = kmalloc(sizeof(*poll), GFP_ATOMIC);
+		if (!poll) {
+			pt->error = -ENOMEM;
+			return;
+		}
+		/* mark as double wq entry */
+		wqe_private |= 1;
+		req->flags |= REQ_F_DOUBLE_POLL;
+		io_init_poll_iocb(poll, first->events, first->wait.func);
+		*poll_ptr = poll;
+		if (req->opcode == IORING_OP_POLL_ADD)
+			req->flags |= REQ_F_ASYNC_DATA;
+	}
+
+	req->flags |= REQ_F_SINGLE_POLL;
+	pt->nr_entries++;
+	poll->head = head;
+	poll->wait.private = (void *) wqe_private;
+
+	if (poll->events & EPOLLEXCLUSIVE)
+		add_wait_queue_exclusive(head, &poll->wait);
+	else
+		add_wait_queue(head, &poll->wait);
+}
+
+static void io_poll_queue_proc(struct file *file, struct wait_queue_head *head,
+			       struct poll_table_struct *p)
+{
+	struct io_poll_table *pt = container_of(p, struct io_poll_table, pt);
+
+	__io_queue_proc(&pt->req->poll, pt, head,
+			(struct io_poll_iocb **) &pt->req->async_data);
+}
+
+static int __io_arm_poll_handler(struct io_kiocb *req,
+				 struct io_poll_iocb *poll,
+				 struct io_poll_table *ipt, __poll_t mask)
+{
+	struct io_ring_ctx *ctx = req->ctx;
+	int v;
+
+	INIT_HLIST_NODE(&req->hash_node);
+	req->work.cancel_seq = atomic_read(&ctx->cancel_seq);
+	io_init_poll_iocb(poll, mask, io_poll_wake);
+	poll->file = req->file;
+
+	req->apoll_events = poll->events;
+
+	ipt->pt._key = mask;
+	ipt->req = req;
+	ipt->error = 0;
+	ipt->nr_entries = 0;
+
+	/*
+	 * Take the ownership to delay any tw execution up until we're done
+	 * with poll arming. see io_poll_get_ownership().
+	 */
+	atomic_set(&req->poll_refs, 1);
+	mask = vfs_poll(req->file, &ipt->pt) & poll->events;
+
+	if (mask && (poll->events & EPOLLONESHOT)) {
+		io_poll_remove_entries(req);
+		/* no one else has access to the req, forget about the ref */
+		return mask;
+	}
+	if (!mask && unlikely(ipt->error || !ipt->nr_entries)) {
+		io_poll_remove_entries(req);
+		if (!ipt->error)
+			ipt->error = -EINVAL;
+		return 0;
+	}
+
+	spin_lock(&ctx->completion_lock);
+	io_poll_req_insert(req);
+	spin_unlock(&ctx->completion_lock);
+
+	if (mask) {
+		/* can't multishot if failed, just queue the event we've got */
+		if (unlikely(ipt->error || !ipt->nr_entries)) {
+			poll->events |= EPOLLONESHOT;
+			req->apoll_events |= EPOLLONESHOT;
+			ipt->error = 0;
+		}
+		__io_poll_execute(req, mask, poll->events);
+		return 0;
+	}
+
+	/*
+	 * Release ownership. If someone tried to queue a tw while it was
+	 * locked, kick it off for them.
+	 */
+	v = atomic_dec_return(&req->poll_refs);
+	if (unlikely(v & IO_POLL_REF_MASK))
+		__io_poll_execute(req, 0, poll->events);
+	return 0;
+}
+
+static void io_async_queue_proc(struct file *file, struct wait_queue_head *head,
+			       struct poll_table_struct *p)
+{
+	struct io_poll_table *pt = container_of(p, struct io_poll_table, pt);
+	struct async_poll *apoll = pt->req->apoll;
+
+	__io_queue_proc(&apoll->poll, pt, head, &apoll->double_poll);
+}
+
+enum {
+	IO_APOLL_OK,
+	IO_APOLL_ABORTED,
+	IO_APOLL_READY
+};
+
+static int io_arm_poll_handler(struct io_kiocb *req, unsigned issue_flags)
+{
+	const struct io_op_def *def = &io_op_defs[req->opcode];
+	struct io_ring_ctx *ctx = req->ctx;
+	struct async_poll *apoll;
+	struct io_poll_table ipt;
+	__poll_t mask = POLLPRI | POLLERR;
+	int ret;
+
+	if (!def->pollin && !def->pollout)
+		return IO_APOLL_ABORTED;
+	if (!file_can_poll(req->file))
+		return IO_APOLL_ABORTED;
+	if ((req->flags & (REQ_F_POLLED|REQ_F_PARTIAL_IO)) == REQ_F_POLLED)
+		return IO_APOLL_ABORTED;
+	if (!(req->flags & REQ_F_APOLL_MULTISHOT))
+		mask |= EPOLLONESHOT;
+
+	if (def->pollin) {
+		mask |= EPOLLIN | EPOLLRDNORM;
+
+		/* If reading from MSG_ERRQUEUE using recvmsg, ignore POLLIN */
+		if ((req->opcode == IORING_OP_RECVMSG) &&
+		    (req->sr_msg.msg_flags & MSG_ERRQUEUE))
+			mask &= ~EPOLLIN;
+	} else {
+		mask |= EPOLLOUT | EPOLLWRNORM;
+	}
+	if (def->poll_exclusive)
+		mask |= EPOLLEXCLUSIVE;
+	if (req->flags & REQ_F_POLLED) {
+		apoll = req->apoll;
+		kfree(apoll->double_poll);
+	} else if (!(issue_flags & IO_URING_F_UNLOCKED) &&
+		   !list_empty(&ctx->apoll_cache)) {
+		apoll = list_first_entry(&ctx->apoll_cache, struct async_poll,
+						poll.wait.entry);
+		list_del_init(&apoll->poll.wait.entry);
+	} else {
+		apoll = kmalloc(sizeof(*apoll), GFP_ATOMIC);
+		if (unlikely(!apoll))
+			return IO_APOLL_ABORTED;
+	}
+	apoll->double_poll = NULL;
+	req->apoll = apoll;
+	req->flags |= REQ_F_POLLED;
+	ipt.pt._qproc = io_async_queue_proc;
+
+	io_kbuf_recycle(req, issue_flags);
+
+	ret = __io_arm_poll_handler(req, &apoll->poll, &ipt, mask);
+	if (ret || ipt.error)
+		return ret ? IO_APOLL_READY : IO_APOLL_ABORTED;
+
+	trace_io_uring_poll_arm(ctx, req, req->cqe.user_data, req->opcode,
+				mask, apoll->poll.events);
+	return IO_APOLL_OK;
+}
+
+/*
+ * Returns true if we found and killed one or more poll requests
+ */
+static __cold bool io_poll_remove_all(struct io_ring_ctx *ctx,
+				      struct task_struct *tsk, bool cancel_all)
+{
+	struct hlist_node *tmp;
+	struct io_kiocb *req;
+	bool found = false;
+	int i;
+
+	spin_lock(&ctx->completion_lock);
+	for (i = 0; i < (1U << ctx->cancel_hash_bits); i++) {
+		struct hlist_head *list;
+
+		list = &ctx->cancel_hash[i];
+		hlist_for_each_entry_safe(req, tmp, list, hash_node) {
+			if (io_match_task_safe(req, tsk, cancel_all)) {
+				hlist_del_init(&req->hash_node);
+				io_poll_cancel_req(req);
+				found = true;
+			}
+		}
+	}
+	spin_unlock(&ctx->completion_lock);
+	return found;
+}
+
+static struct io_kiocb *io_poll_find(struct io_ring_ctx *ctx, bool poll_only,
+				     struct io_cancel_data *cd)
+	__must_hold(&ctx->completion_lock)
+{
+	struct hlist_head *list;
+	struct io_kiocb *req;
+
+	list = &ctx->cancel_hash[hash_long(cd->data, ctx->cancel_hash_bits)];
+	hlist_for_each_entry(req, list, hash_node) {
+		if (cd->data != req->cqe.user_data)
+			continue;
+		if (poll_only && req->opcode != IORING_OP_POLL_ADD)
+			continue;
+		if (cd->flags & IORING_ASYNC_CANCEL_ALL) {
+			if (cd->seq == req->work.cancel_seq)
+				continue;
+			req->work.cancel_seq = cd->seq;
+		}
+		return req;
+	}
+	return NULL;
+}
+
+static struct io_kiocb *io_poll_file_find(struct io_ring_ctx *ctx,
+					  struct io_cancel_data *cd)
+	__must_hold(&ctx->completion_lock)
+{
+	struct io_kiocb *req;
+	int i;
+
+	for (i = 0; i < (1U << ctx->cancel_hash_bits); i++) {
+		struct hlist_head *list;
+
+		list = &ctx->cancel_hash[i];
+		hlist_for_each_entry(req, list, hash_node) {
+			if (!(cd->flags & IORING_ASYNC_CANCEL_ANY) &&
+			    req->file != cd->file)
+				continue;
+			if (cd->seq == req->work.cancel_seq)
+				continue;
+			req->work.cancel_seq = cd->seq;
+			return req;
+		}
+	}
+	return NULL;
+}
+
+static bool io_poll_disarm(struct io_kiocb *req)
+	__must_hold(&ctx->completion_lock)
+{
+	if (!io_poll_get_ownership(req))
+		return false;
+	io_poll_remove_entries(req);
+	hash_del(&req->hash_node);
+	return true;
+}
+
+static int io_poll_cancel(struct io_ring_ctx *ctx, struct io_cancel_data *cd)
+	__must_hold(&ctx->completion_lock)
+{
+	struct io_kiocb *req;
+
+	if (cd->flags & (IORING_ASYNC_CANCEL_FD|IORING_ASYNC_CANCEL_ANY))
+		req = io_poll_file_find(ctx, cd);
+	else
+		req = io_poll_find(ctx, false, cd);
+	if (!req)
+		return -ENOENT;
+	io_poll_cancel_req(req);
+	return 0;
+}
+
+static __poll_t io_poll_parse_events(const struct io_uring_sqe *sqe,
+				     unsigned int flags)
+{
+	u32 events;
+
+	events = READ_ONCE(sqe->poll32_events);
+#ifdef __BIG_ENDIAN
+	events = swahw32(events);
+#endif
+	if (!(flags & IORING_POLL_ADD_MULTI))
+		events |= EPOLLONESHOT;
+	return demangle_poll(events) | (events & (EPOLLEXCLUSIVE|EPOLLONESHOT));
+}
+
+static int io_poll_remove_prep(struct io_kiocb *req,
+			       const struct io_uring_sqe *sqe)
+{
+	struct io_poll_update *upd = &req->poll_update;
+	u32 flags;
+
+	if (sqe->buf_index || sqe->splice_fd_in)
+		return -EINVAL;
+	flags = READ_ONCE(sqe->len);
+	if (flags & ~(IORING_POLL_UPDATE_EVENTS | IORING_POLL_UPDATE_USER_DATA |
+		      IORING_POLL_ADD_MULTI))
+		return -EINVAL;
+	/* meaningless without update */
+	if (flags == IORING_POLL_ADD_MULTI)
+		return -EINVAL;
+
+	upd->old_user_data = READ_ONCE(sqe->addr);
+	upd->update_events = flags & IORING_POLL_UPDATE_EVENTS;
+	upd->update_user_data = flags & IORING_POLL_UPDATE_USER_DATA;
+
+	upd->new_user_data = READ_ONCE(sqe->off);
+	if (!upd->update_user_data && upd->new_user_data)
+		return -EINVAL;
+	if (upd->update_events)
+		upd->events = io_poll_parse_events(sqe, flags);
+	else if (sqe->poll32_events)
+		return -EINVAL;
+
+	return 0;
+}
+
+static int io_poll_add_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+	struct io_poll_iocb *poll = &req->poll;
+	u32 flags;
+
+	if (sqe->buf_index || sqe->off || sqe->addr)
+		return -EINVAL;
+	flags = READ_ONCE(sqe->len);
+	if (flags & ~IORING_POLL_ADD_MULTI)
+		return -EINVAL;
+	if ((flags & IORING_POLL_ADD_MULTI) && (req->flags & REQ_F_CQE_SKIP))
+		return -EINVAL;
+
+	io_req_set_refcount(req);
+	poll->events = io_poll_parse_events(sqe, flags);
+	return 0;
+}
+
+static int io_poll_add(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_poll_iocb *poll = &req->poll;
+	struct io_poll_table ipt;
+	int ret;
+
+	ipt.pt._qproc = io_poll_queue_proc;
+
+	ret = __io_arm_poll_handler(req, &req->poll, &ipt, poll->events);
+	if (!ret && ipt.error)
+		req_set_fail(req);
+	ret = ret ?: ipt.error;
+	if (ret)
+		__io_req_complete(req, issue_flags, ret, 0);
+	return 0;
+}
+
+static int io_poll_remove(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_cancel_data cd = { .data = req->poll_update.old_user_data, };
+	struct io_ring_ctx *ctx = req->ctx;
+	struct io_kiocb *preq;
+	int ret2, ret = 0;
+	bool locked;
+
+	spin_lock(&ctx->completion_lock);
+	preq = io_poll_find(ctx, true, &cd);
+	if (!preq || !io_poll_disarm(preq)) {
+		spin_unlock(&ctx->completion_lock);
+		ret = preq ? -EALREADY : -ENOENT;
+		goto out;
+	}
+	spin_unlock(&ctx->completion_lock);
+
+	if (req->poll_update.update_events || req->poll_update.update_user_data) {
+		/* only mask one event flags, keep behavior flags */
+		if (req->poll_update.update_events) {
+			preq->poll.events &= ~0xffff;
+			preq->poll.events |= req->poll_update.events & 0xffff;
+			preq->poll.events |= IO_POLL_UNMASK;
+		}
+		if (req->poll_update.update_user_data)
+			preq->cqe.user_data = req->poll_update.new_user_data;
+
+		ret2 = io_poll_add(preq, issue_flags);
+		/* successfully updated, don't complete poll request */
+		if (!ret2)
+			goto out;
+	}
+
+	req_set_fail(preq);
+	preq->cqe.res = -ECANCELED;
+	locked = !(issue_flags & IO_URING_F_UNLOCKED);
+	io_req_task_complete(preq, &locked);
+out:
+	if (ret < 0)
+		req_set_fail(req);
+	/* complete update request, we're done with it */
+	__io_req_complete(req, issue_flags, ret, 0);
+	return 0;
+}
+
+static enum hrtimer_restart io_timeout_fn(struct hrtimer *timer)
+{
+	struct io_timeout_data *data = container_of(timer,
+						struct io_timeout_data, timer);
+	struct io_kiocb *req = data->req;
+	struct io_ring_ctx *ctx = req->ctx;
+	unsigned long flags;
+
+	spin_lock_irqsave(&ctx->timeout_lock, flags);
+	list_del_init(&req->timeout.list);
+	atomic_set(&req->ctx->cq_timeouts,
+		atomic_read(&req->ctx->cq_timeouts) + 1);
+	spin_unlock_irqrestore(&ctx->timeout_lock, flags);
+
+	if (!(data->flags & IORING_TIMEOUT_ETIME_SUCCESS))
+		req_set_fail(req);
+
+	req->cqe.res = -ETIME;
+	req->io_task_work.func = io_req_task_complete;
+	io_req_task_work_add(req);
+	return HRTIMER_NORESTART;
+}
+
+static struct io_kiocb *io_timeout_extract(struct io_ring_ctx *ctx,
+					   struct io_cancel_data *cd)
+	__must_hold(&ctx->timeout_lock)
+{
+	struct io_timeout_data *io;
+	struct io_kiocb *req;
+	bool found = false;
+
+	list_for_each_entry(req, &ctx->timeout_list, timeout.list) {
+		if (!(cd->flags & IORING_ASYNC_CANCEL_ANY) &&
+		    cd->data != req->cqe.user_data)
+			continue;
+		if (cd->flags & (IORING_ASYNC_CANCEL_ALL|IORING_ASYNC_CANCEL_ANY)) {
+			if (cd->seq == req->work.cancel_seq)
+				continue;
+			req->work.cancel_seq = cd->seq;
+		}
+		found = true;
+		break;
+	}
+	if (!found)
+		return ERR_PTR(-ENOENT);
+
+	io = req->async_data;
+	if (hrtimer_try_to_cancel(&io->timer) == -1)
+		return ERR_PTR(-EALREADY);
+	list_del_init(&req->timeout.list);
+	return req;
+}
+
+static int io_timeout_cancel(struct io_ring_ctx *ctx, struct io_cancel_data *cd)
+	__must_hold(&ctx->completion_lock)
+{
+	struct io_kiocb *req;
+
+	spin_lock_irq(&ctx->timeout_lock);
+	req = io_timeout_extract(ctx, cd);
+	spin_unlock_irq(&ctx->timeout_lock);
+
+	if (IS_ERR(req))
+		return PTR_ERR(req);
+	io_req_task_queue_fail(req, -ECANCELED);
+	return 0;
+}
+
+static clockid_t io_timeout_get_clock(struct io_timeout_data *data)
+{
+	switch (data->flags & IORING_TIMEOUT_CLOCK_MASK) {
+	case IORING_TIMEOUT_BOOTTIME:
+		return CLOCK_BOOTTIME;
+	case IORING_TIMEOUT_REALTIME:
+		return CLOCK_REALTIME;
+	default:
+		/* can't happen, vetted at prep time */
+		WARN_ON_ONCE(1);
+		fallthrough;
+	case 0:
+		return CLOCK_MONOTONIC;
+	}
+}
+
+static int io_linked_timeout_update(struct io_ring_ctx *ctx, __u64 user_data,
+				    struct timespec64 *ts, enum hrtimer_mode mode)
+	__must_hold(&ctx->timeout_lock)
+{
+	struct io_timeout_data *io;
+	struct io_kiocb *req;
+	bool found = false;
+
+	list_for_each_entry(req, &ctx->ltimeout_list, timeout.list) {
+		found = user_data == req->cqe.user_data;
+		if (found)
+			break;
+	}
+	if (!found)
+		return -ENOENT;
+
+	io = req->async_data;
+	if (hrtimer_try_to_cancel(&io->timer) == -1)
+		return -EALREADY;
+	hrtimer_init(&io->timer, io_timeout_get_clock(io), mode);
+	io->timer.function = io_link_timeout_fn;
+	hrtimer_start(&io->timer, timespec64_to_ktime(*ts), mode);
+	return 0;
+}
+
+static int io_timeout_update(struct io_ring_ctx *ctx, __u64 user_data,
+			     struct timespec64 *ts, enum hrtimer_mode mode)
+	__must_hold(&ctx->timeout_lock)
+{
+	struct io_cancel_data cd = { .data = user_data, };
+	struct io_kiocb *req = io_timeout_extract(ctx, &cd);
+	struct io_timeout_data *data;
+
+	if (IS_ERR(req))
+		return PTR_ERR(req);
+
+	req->timeout.off = 0; /* noseq */
+	data = req->async_data;
+	list_add_tail(&req->timeout.list, &ctx->timeout_list);
+	hrtimer_init(&data->timer, io_timeout_get_clock(data), mode);
+	data->timer.function = io_timeout_fn;
+	hrtimer_start(&data->timer, timespec64_to_ktime(*ts), mode);
+	return 0;
+}
+
+static int io_timeout_remove_prep(struct io_kiocb *req,
+				  const struct io_uring_sqe *sqe)
+{
+	struct io_timeout_rem *tr = &req->timeout_rem;
+
+	if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT)))
+		return -EINVAL;
+	if (sqe->buf_index || sqe->len || sqe->splice_fd_in)
+		return -EINVAL;
+
+	tr->ltimeout = false;
+	tr->addr = READ_ONCE(sqe->addr);
+	tr->flags = READ_ONCE(sqe->timeout_flags);
+	if (tr->flags & IORING_TIMEOUT_UPDATE_MASK) {
+		if (hweight32(tr->flags & IORING_TIMEOUT_CLOCK_MASK) > 1)
+			return -EINVAL;
+		if (tr->flags & IORING_LINK_TIMEOUT_UPDATE)
+			tr->ltimeout = true;
+		if (tr->flags & ~(IORING_TIMEOUT_UPDATE_MASK|IORING_TIMEOUT_ABS))
+			return -EINVAL;
+		if (get_timespec64(&tr->ts, u64_to_user_ptr(sqe->addr2)))
+			return -EFAULT;
+		if (tr->ts.tv_sec < 0 || tr->ts.tv_nsec < 0)
+			return -EINVAL;
+	} else if (tr->flags) {
+		/* timeout removal doesn't support flags */
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static inline enum hrtimer_mode io_translate_timeout_mode(unsigned int flags)
+{
+	return (flags & IORING_TIMEOUT_ABS) ? HRTIMER_MODE_ABS
+					    : HRTIMER_MODE_REL;
+}
+
+/*
+ * Remove or update an existing timeout command
+ */
+static int io_timeout_remove(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_timeout_rem *tr = &req->timeout_rem;
+	struct io_ring_ctx *ctx = req->ctx;
+	int ret;
+
+	if (!(req->timeout_rem.flags & IORING_TIMEOUT_UPDATE)) {
+		struct io_cancel_data cd = { .data = tr->addr, };
+
+		spin_lock(&ctx->completion_lock);
+		ret = io_timeout_cancel(ctx, &cd);
+		spin_unlock(&ctx->completion_lock);
+	} else {
+		enum hrtimer_mode mode = io_translate_timeout_mode(tr->flags);
+
+		spin_lock_irq(&ctx->timeout_lock);
+		if (tr->ltimeout)
+			ret = io_linked_timeout_update(ctx, tr->addr, &tr->ts, mode);
+		else
+			ret = io_timeout_update(ctx, tr->addr, &tr->ts, mode);
+		spin_unlock_irq(&ctx->timeout_lock);
+	}
+
+	if (ret < 0)
+		req_set_fail(req);
+	io_req_complete_post(req, ret, 0);
+	return 0;
+}
+
+static int __io_timeout_prep(struct io_kiocb *req,
+			     const struct io_uring_sqe *sqe,
+			     bool is_timeout_link)
+{
+	struct io_timeout_data *data;
+	unsigned flags;
+	u32 off = READ_ONCE(sqe->off);
+
+	if (sqe->buf_index || sqe->len != 1 || sqe->splice_fd_in)
+		return -EINVAL;
+	if (off && is_timeout_link)
+		return -EINVAL;
+	flags = READ_ONCE(sqe->timeout_flags);
+	if (flags & ~(IORING_TIMEOUT_ABS | IORING_TIMEOUT_CLOCK_MASK |
+		      IORING_TIMEOUT_ETIME_SUCCESS))
+		return -EINVAL;
+	/* more than one clock specified is invalid, obviously */
+	if (hweight32(flags & IORING_TIMEOUT_CLOCK_MASK) > 1)
+		return -EINVAL;
+
+	INIT_LIST_HEAD(&req->timeout.list);
+	req->timeout.off = off;
+	if (unlikely(off && !req->ctx->off_timeout_used))
+		req->ctx->off_timeout_used = true;
+
+	if (WARN_ON_ONCE(req_has_async_data(req)))
+		return -EFAULT;
+	if (io_alloc_async_data(req))
+		return -ENOMEM;
+
+	data = req->async_data;
+	data->req = req;
+	data->flags = flags;
+
+	if (get_timespec64(&data->ts, u64_to_user_ptr(sqe->addr)))
+		return -EFAULT;
+
+	if (data->ts.tv_sec < 0 || data->ts.tv_nsec < 0)
+		return -EINVAL;
+
+	INIT_LIST_HEAD(&req->timeout.list);
+	data->mode = io_translate_timeout_mode(flags);
+	hrtimer_init(&data->timer, io_timeout_get_clock(data), data->mode);
+
+	if (is_timeout_link) {
+		struct io_submit_link *link = &req->ctx->submit_state.link;
+
+		if (!link->head)
+			return -EINVAL;
+		if (link->last->opcode == IORING_OP_LINK_TIMEOUT)
+			return -EINVAL;
+		req->timeout.head = link->last;
+		link->last->flags |= REQ_F_ARM_LTIMEOUT;
+	}
+	return 0;
+}
+
+static int io_timeout_prep(struct io_kiocb *req,
+			   const struct io_uring_sqe *sqe)
+{
+	return __io_timeout_prep(req, sqe, false);
+}
+
+static int io_link_timeout_prep(struct io_kiocb *req,
+				const struct io_uring_sqe *sqe)
+{
+	return __io_timeout_prep(req, sqe, true);
+}
+
+static int io_timeout(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_ring_ctx *ctx = req->ctx;
+	struct io_timeout_data *data = req->async_data;
+	struct list_head *entry;
+	u32 tail, off = req->timeout.off;
+
+	spin_lock_irq(&ctx->timeout_lock);
+
+	/*
+	 * sqe->off holds how many events that need to occur for this
+	 * timeout event to be satisfied. If it isn't set, then this is
+	 * a pure timeout request, sequence isn't used.
+	 */
+	if (io_is_timeout_noseq(req)) {
+		entry = ctx->timeout_list.prev;
+		goto add;
+	}
+
+	tail = ctx->cached_cq_tail - atomic_read(&ctx->cq_timeouts);
+	req->timeout.target_seq = tail + off;
+
+	/* Update the last seq here in case io_flush_timeouts() hasn't.
+	 * This is safe because ->completion_lock is held, and submissions
+	 * and completions are never mixed in the same ->completion_lock section.
+	 */
+	ctx->cq_last_tm_flush = tail;
+
+	/*
+	 * Insertion sort, ensuring the first entry in the list is always
+	 * the one we need first.
+	 */
+	list_for_each_prev(entry, &ctx->timeout_list) {
+		struct io_kiocb *nxt = list_entry(entry, struct io_kiocb,
+						  timeout.list);
+
+		if (io_is_timeout_noseq(nxt))
+			continue;
+		/* nxt.seq is behind @tail, otherwise would've been completed */
+		if (off >= nxt->timeout.target_seq - tail)
+			break;
+	}
+add:
+	list_add(&req->timeout.list, entry);
+	data->timer.function = io_timeout_fn;
+	hrtimer_start(&data->timer, timespec64_to_ktime(data->ts), data->mode);
+	spin_unlock_irq(&ctx->timeout_lock);
+	return 0;
+}
+
+static bool io_cancel_cb(struct io_wq_work *work, void *data)
+{
+	struct io_kiocb *req = container_of(work, struct io_kiocb, work);
+	struct io_cancel_data *cd = data;
+
+	if (req->ctx != cd->ctx)
+		return false;
+	if (cd->flags & IORING_ASYNC_CANCEL_ANY) {
+		;
+	} else if (cd->flags & IORING_ASYNC_CANCEL_FD) {
+		if (req->file != cd->file)
+			return false;
+	} else {
+		if (req->cqe.user_data != cd->data)
+			return false;
+	}
+	if (cd->flags & (IORING_ASYNC_CANCEL_ALL|IORING_ASYNC_CANCEL_ANY)) {
+		if (cd->seq == req->work.cancel_seq)
+			return false;
+		req->work.cancel_seq = cd->seq;
+	}
+	return true;
+}
+
+static int io_async_cancel_one(struct io_uring_task *tctx,
+			       struct io_cancel_data *cd)
+{
+	enum io_wq_cancel cancel_ret;
+	int ret = 0;
+	bool all;
+
+	if (!tctx || !tctx->io_wq)
+		return -ENOENT;
+
+	all = cd->flags & (IORING_ASYNC_CANCEL_ALL|IORING_ASYNC_CANCEL_ANY);
+	cancel_ret = io_wq_cancel_cb(tctx->io_wq, io_cancel_cb, cd, all);
+	switch (cancel_ret) {
+	case IO_WQ_CANCEL_OK:
+		ret = 0;
+		break;
+	case IO_WQ_CANCEL_RUNNING:
+		ret = -EALREADY;
+		break;
+	case IO_WQ_CANCEL_NOTFOUND:
+		ret = -ENOENT;
+		break;
+	}
+
+	return ret;
+}
+
+static int io_try_cancel(struct io_kiocb *req, struct io_cancel_data *cd)
+{
+	struct io_ring_ctx *ctx = req->ctx;
+	int ret;
+
+	WARN_ON_ONCE(!io_wq_current_is_worker() && req->task != current);
+
+	ret = io_async_cancel_one(req->task->io_uring, cd);
+	/*
+	 * Fall-through even for -EALREADY, as we may have poll armed
+	 * that need unarming.
+	 */
+	if (!ret)
+		return 0;
+
+	spin_lock(&ctx->completion_lock);
+	ret = io_poll_cancel(ctx, cd);
+	if (ret != -ENOENT)
+		goto out;
+	if (!(cd->flags & IORING_ASYNC_CANCEL_FD))
+		ret = io_timeout_cancel(ctx, cd);
+out:
+	spin_unlock(&ctx->completion_lock);
+	return ret;
+}
+
+#define CANCEL_FLAGS	(IORING_ASYNC_CANCEL_ALL | IORING_ASYNC_CANCEL_FD | \
+			 IORING_ASYNC_CANCEL_ANY)
+
+static int io_async_cancel_prep(struct io_kiocb *req,
+				const struct io_uring_sqe *sqe)
+{
+	if (unlikely(req->flags & REQ_F_BUFFER_SELECT))
+		return -EINVAL;
+	if (sqe->off || sqe->len || sqe->splice_fd_in)
+		return -EINVAL;
+
+	req->cancel.addr = READ_ONCE(sqe->addr);
+	req->cancel.flags = READ_ONCE(sqe->cancel_flags);
+	if (req->cancel.flags & ~CANCEL_FLAGS)
+		return -EINVAL;
+	if (req->cancel.flags & IORING_ASYNC_CANCEL_FD) {
+		if (req->cancel.flags & IORING_ASYNC_CANCEL_ANY)
+			return -EINVAL;
+		req->cancel.fd = READ_ONCE(sqe->fd);
+	}
+
+	return 0;
+}
+
+static int __io_async_cancel(struct io_cancel_data *cd, struct io_kiocb *req,
+			     unsigned int issue_flags)
+{
+	bool all = cd->flags & (IORING_ASYNC_CANCEL_ALL|IORING_ASYNC_CANCEL_ANY);
+	struct io_ring_ctx *ctx = cd->ctx;
+	struct io_tctx_node *node;
+	int ret, nr = 0;
+
+	do {
+		ret = io_try_cancel(req, cd);
+		if (ret == -ENOENT)
+			break;
+		if (!all)
+			return ret;
+		nr++;
+	} while (1);
+
+	/* slow path, try all io-wq's */
+	io_ring_submit_lock(ctx, issue_flags);
+	ret = -ENOENT;
+	list_for_each_entry(node, &ctx->tctx_list, ctx_node) {
+		struct io_uring_task *tctx = node->task->io_uring;
+
+		ret = io_async_cancel_one(tctx, cd);
+		if (ret != -ENOENT) {
+			if (!all)
+				break;
+			nr++;
+		}
+	}
+	io_ring_submit_unlock(ctx, issue_flags);
+	return all ? nr : ret;
+}
+
+static int io_async_cancel(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_cancel_data cd = {
+		.ctx	= req->ctx,
+		.data	= req->cancel.addr,
+		.flags	= req->cancel.flags,
+		.seq	= atomic_inc_return(&req->ctx->cancel_seq),
+	};
+	int ret;
+
+	if (cd.flags & IORING_ASYNC_CANCEL_FD) {
+		if (req->flags & REQ_F_FIXED_FILE)
+			req->file = io_file_get_fixed(req, req->cancel.fd,
+							issue_flags);
+		else
+			req->file = io_file_get_normal(req, req->cancel.fd);
+		if (!req->file) {
+			ret = -EBADF;
+			goto done;
+		}
+		cd.file = req->file;
+	}
+
+	ret = __io_async_cancel(&cd, req, issue_flags);
+done:
+	if (ret < 0)
+		req_set_fail(req);
+	io_req_complete_post(req, ret, 0);
+	return 0;
+}
+
+static int io_files_update_prep(struct io_kiocb *req,
+				const struct io_uring_sqe *sqe)
+{
+	if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT)))
+		return -EINVAL;
+	if (sqe->rw_flags || sqe->splice_fd_in)
+		return -EINVAL;
+
+	req->rsrc_update.offset = READ_ONCE(sqe->off);
+	req->rsrc_update.nr_args = READ_ONCE(sqe->len);
+	if (!req->rsrc_update.nr_args)
+		return -EINVAL;
+	req->rsrc_update.arg = READ_ONCE(sqe->addr);
+	return 0;
+}
+
+static int io_files_update_with_index_alloc(struct io_kiocb *req,
+					    unsigned int issue_flags)
+{
+	__s32 __user *fds = u64_to_user_ptr(req->rsrc_update.arg);
+	unsigned int done;
+	struct file *file;
+	int ret, fd;
+
+	if (!req->ctx->file_data)
+		return -ENXIO;
+
+	for (done = 0; done < req->rsrc_update.nr_args; done++) {
+		if (copy_from_user(&fd, &fds[done], sizeof(fd))) {
+			ret = -EFAULT;
+			break;
+		}
+
+		file = fget(fd);
+		if (!file) {
+			ret = -EBADF;
+			break;
+		}
+		ret = io_fixed_fd_install(req, issue_flags, file,
+					  IORING_FILE_INDEX_ALLOC);
+		if (ret < 0)
+			break;
+		if (copy_to_user(&fds[done], &ret, sizeof(ret))) {
+			__io_close_fixed(req, issue_flags, ret);
+			ret = -EFAULT;
+			break;
+		}
+	}
+
+	if (done)
+		return done;
+	return ret;
+}
+
+static int io_files_update(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_ring_ctx *ctx = req->ctx;
+	struct io_uring_rsrc_update2 up;
+	int ret;
+
+	up.offset = req->rsrc_update.offset;
+	up.data = req->rsrc_update.arg;
+	up.nr = 0;
+	up.tags = 0;
+	up.resv = 0;
+	up.resv2 = 0;
+
+	if (req->rsrc_update.offset == IORING_FILE_INDEX_ALLOC) {
+		ret = io_files_update_with_index_alloc(req, issue_flags);
+	} else {
+		io_ring_submit_lock(ctx, issue_flags);
+		ret = __io_register_rsrc_update(ctx, IORING_RSRC_FILE,
+				&up, req->rsrc_update.nr_args);
+		io_ring_submit_unlock(ctx, issue_flags);
+	}
+
+	if (ret < 0)
+		req_set_fail(req);
+	__io_req_complete(req, issue_flags, ret, 0);
+	return 0;
+}
+
+static int io_req_prep_async(struct io_kiocb *req)
+{
+	const struct io_op_def *def = &io_op_defs[req->opcode];
+
+	/* assign early for deferred execution for non-fixed file */
+	if (def->needs_file && !(req->flags & REQ_F_FIXED_FILE))
+		req->file = io_file_get_normal(req, req->cqe.fd);
+	if (!def->needs_async_setup)
+		return 0;
+	if (WARN_ON_ONCE(req_has_async_data(req)))
+		return -EFAULT;
+	if (io_alloc_async_data(req))
+		return -EAGAIN;
+
+	switch (req->opcode) {
+	case IORING_OP_READV:
+		return io_readv_prep_async(req);
+	case IORING_OP_WRITEV:
+		return io_writev_prep_async(req);
+	case IORING_OP_SENDMSG:
+		return io_sendmsg_prep_async(req);
+	case IORING_OP_RECVMSG:
+		return io_recvmsg_prep_async(req);
+	case IORING_OP_CONNECT:
+		return io_connect_prep_async(req);
+	case IORING_OP_URING_CMD:
+		return io_uring_cmd_prep_async(req);
+	}
+
+	printk_once(KERN_WARNING "io_uring: unhandled opcode %d\n",
+			req->opcode);
+	return -EINVAL;
+}
+
+static u32 io_get_sequence(struct io_kiocb *req)
+{
+	u32 seq = req->ctx->cached_sq_head;
+	struct io_kiocb *cur;
+
+	/* need original cached_sq_head, but it was increased for each req */
+	io_for_each_link(cur, req)
+		seq--;
+	return seq;
+}
+
+static __cold void io_drain_req(struct io_kiocb *req)
+{
+	struct io_ring_ctx *ctx = req->ctx;
+	struct io_defer_entry *de;
+	int ret;
+	u32 seq = io_get_sequence(req);
+
+	/* Still need defer if there is pending req in defer list. */
+	spin_lock(&ctx->completion_lock);
+	if (!req_need_defer(req, seq) && list_empty_careful(&ctx->defer_list)) {
+		spin_unlock(&ctx->completion_lock);
+queue:
+		ctx->drain_active = false;
+		io_req_task_queue(req);
+		return;
+	}
+	spin_unlock(&ctx->completion_lock);
+
+	ret = io_req_prep_async(req);
+	if (ret) {
+fail:
+		io_req_complete_failed(req, ret);
+		return;
+	}
+	io_prep_async_link(req);
+	de = kmalloc(sizeof(*de), GFP_KERNEL);
+	if (!de) {
+		ret = -ENOMEM;
+		goto fail;
+	}
+
+	spin_lock(&ctx->completion_lock);
+	if (!req_need_defer(req, seq) && list_empty(&ctx->defer_list)) {
+		spin_unlock(&ctx->completion_lock);
+		kfree(de);
+		goto queue;
+	}
+
+	trace_io_uring_defer(ctx, req, req->cqe.user_data, req->opcode);
+	de->req = req;
+	de->seq = seq;
+	list_add_tail(&de->list, &ctx->defer_list);
+	spin_unlock(&ctx->completion_lock);
+}
+
+static void io_clean_op(struct io_kiocb *req)
+{
+	if (req->flags & REQ_F_BUFFER_SELECTED) {
+		spin_lock(&req->ctx->completion_lock);
+		io_put_kbuf_comp(req);
+		spin_unlock(&req->ctx->completion_lock);
+	}
+
+	if (req->flags & REQ_F_NEED_CLEANUP) {
+		switch (req->opcode) {
+		case IORING_OP_READV:
+		case IORING_OP_READ_FIXED:
+		case IORING_OP_READ:
+		case IORING_OP_WRITEV:
+		case IORING_OP_WRITE_FIXED:
+		case IORING_OP_WRITE: {
+			struct io_async_rw *io = req->async_data;
+
+			kfree(io->free_iovec);
+			break;
+			}
+		case IORING_OP_RECVMSG:
+		case IORING_OP_SENDMSG: {
+			struct io_async_msghdr *io = req->async_data;
+
+			kfree(io->free_iov);
+			break;
+			}
+		case IORING_OP_OPENAT:
+		case IORING_OP_OPENAT2:
+			if (req->open.filename)
+				putname(req->open.filename);
+			break;
+		case IORING_OP_RENAMEAT:
+			putname(req->rename.oldpath);
+			putname(req->rename.newpath);
+			break;
+		case IORING_OP_UNLINKAT:
+			putname(req->unlink.filename);
+			break;
+		case IORING_OP_MKDIRAT:
+			putname(req->mkdir.filename);
+			break;
+		case IORING_OP_SYMLINKAT:
+			putname(req->symlink.oldpath);
+			putname(req->symlink.newpath);
+			break;
+		case IORING_OP_LINKAT:
+			putname(req->hardlink.oldpath);
+			putname(req->hardlink.newpath);
+			break;
+		case IORING_OP_STATX:
+			if (req->statx.filename)
+				putname(req->statx.filename);
+			break;
+		case IORING_OP_SETXATTR:
+		case IORING_OP_FSETXATTR:
+		case IORING_OP_GETXATTR:
+		case IORING_OP_FGETXATTR:
+			__io_xattr_finish(req);
+			break;
+		}
+	}
+	if ((req->flags & REQ_F_POLLED) && req->apoll) {
+		kfree(req->apoll->double_poll);
+		kfree(req->apoll);
+		req->apoll = NULL;
+	}
+	if (req->flags & REQ_F_INFLIGHT) {
+		struct io_uring_task *tctx = req->task->io_uring;
+
+		atomic_dec(&tctx->inflight_tracked);
+	}
+	if (req->flags & REQ_F_CREDS)
+		put_cred(req->creds);
+	if (req->flags & REQ_F_ASYNC_DATA) {
+		kfree(req->async_data);
+		req->async_data = NULL;
+	}
+	req->flags &= ~IO_REQ_CLEAN_FLAGS;
+}
+
+static bool io_assign_file(struct io_kiocb *req, unsigned int issue_flags)
+{
+	if (req->file || !io_op_defs[req->opcode].needs_file)
+		return true;
+
+	if (req->flags & REQ_F_FIXED_FILE)
+		req->file = io_file_get_fixed(req, req->cqe.fd, issue_flags);
+	else
+		req->file = io_file_get_normal(req, req->cqe.fd);
+
+	return !!req->file;
+}
+
+static int io_issue_sqe(struct io_kiocb *req, unsigned int issue_flags)
+{
+	const struct io_op_def *def = &io_op_defs[req->opcode];
+	const struct cred *creds = NULL;
+	int ret;
+
+	if (unlikely(!io_assign_file(req, issue_flags)))
+		return -EBADF;
+
+	if (unlikely((req->flags & REQ_F_CREDS) && req->creds != current_cred()))
+		creds = override_creds(req->creds);
+
+	if (!def->audit_skip)
+		audit_uring_entry(req->opcode);
+
+	ret = def->issue(req, issue_flags);
+
+	if (!def->audit_skip)
+		audit_uring_exit(!ret, ret);
+
+	if (creds)
+		revert_creds(creds);
+	if (ret)
+		return ret;
+	/* If the op doesn't have a file, we're not polling for it */
+	if ((req->ctx->flags & IORING_SETUP_IOPOLL) && req->file)
+		io_iopoll_req_issued(req, issue_flags);
+
+	return 0;
+}
+
+static struct io_wq_work *io_wq_free_work(struct io_wq_work *work)
+{
+	struct io_kiocb *req = container_of(work, struct io_kiocb, work);
+
+	req = io_put_req_find_next(req);
+	return req ? &req->work : NULL;
+}
+
+static void io_wq_submit_work(struct io_wq_work *work)
+{
+	struct io_kiocb *req = container_of(work, struct io_kiocb, work);
+	const struct io_op_def *def = &io_op_defs[req->opcode];
+	unsigned int issue_flags = IO_URING_F_UNLOCKED;
+	bool needs_poll = false;
+	int ret = 0, err = -ECANCELED;
+
+	/* one will be dropped by ->io_free_work() after returning to io-wq */
+	if (!(req->flags & REQ_F_REFCOUNT))
+		__io_req_set_refcount(req, 2);
+	else
+		req_ref_get(req);
+
+	io_arm_ltimeout(req);
+
+	/* either cancelled or io-wq is dying, so don't touch tctx->iowq */
+	if (work->flags & IO_WQ_WORK_CANCEL) {
+fail:
+		io_req_task_queue_fail(req, err);
+		return;
+	}
+	if (!io_assign_file(req, issue_flags)) {
+		err = -EBADF;
+		work->flags |= IO_WQ_WORK_CANCEL;
+		goto fail;
+	}
+
+	if (req->flags & REQ_F_FORCE_ASYNC) {
+		bool opcode_poll = def->pollin || def->pollout;
+
+		if (opcode_poll && file_can_poll(req->file)) {
+			needs_poll = true;
+			issue_flags |= IO_URING_F_NONBLOCK;
+		}
+	}
+
+	do {
+		ret = io_issue_sqe(req, issue_flags);
+		if (ret != -EAGAIN)
+			break;
+		/*
+		 * We can get EAGAIN for iopolled IO even though we're
+		 * forcing a sync submission from here, since we can't
+		 * wait for request slots on the block side.
+		 */
+		if (!needs_poll) {
+			if (!(req->ctx->flags & IORING_SETUP_IOPOLL))
+				break;
+			cond_resched();
+			continue;
+		}
+
+		if (io_arm_poll_handler(req, issue_flags) == IO_APOLL_OK)
+			return;
+		/* aborted or ready, in either case retry blocking */
+		needs_poll = false;
+		issue_flags &= ~IO_URING_F_NONBLOCK;
+	} while (1);
+
+	/* avoid locking problems by failing it from a clean context */
+	if (ret)
+		io_req_task_queue_fail(req, ret);
+}
+
+static inline struct io_fixed_file *io_fixed_file_slot(struct io_file_table *table,
+						       unsigned i)
+{
+	return &table->files[i];
+}
+
+static inline struct file *io_file_from_index(struct io_ring_ctx *ctx,
+					      int index)
+{
+	struct io_fixed_file *slot = io_fixed_file_slot(&ctx->file_table, index);
+
+	return (struct file *) (slot->file_ptr & FFS_MASK);
+}
+
+static void io_fixed_file_set(struct io_fixed_file *file_slot, struct file *file)
+{
+	unsigned long file_ptr = (unsigned long) file;
+
+	file_ptr |= io_file_get_flags(file);
+	file_slot->file_ptr = file_ptr;
+}
+
+static inline struct file *io_file_get_fixed(struct io_kiocb *req, int fd,
+					     unsigned int issue_flags)
+{
+	struct io_ring_ctx *ctx = req->ctx;
+	struct file *file = NULL;
+	unsigned long file_ptr;
+
+	io_ring_submit_lock(ctx, issue_flags);
+
+	if (unlikely((unsigned int)fd >= ctx->nr_user_files))
+		goto out;
+	fd = array_index_nospec(fd, ctx->nr_user_files);
+	file_ptr = io_fixed_file_slot(&ctx->file_table, fd)->file_ptr;
+	file = (struct file *) (file_ptr & FFS_MASK);
+	file_ptr &= ~FFS_MASK;
+	/* mask in overlapping REQ_F and FFS bits */
+	req->flags |= (file_ptr << REQ_F_SUPPORT_NOWAIT_BIT);
+	io_req_set_rsrc_node(req, ctx, 0);
+	WARN_ON_ONCE(file && !test_bit(fd, ctx->file_table.bitmap));
+out:
+	io_ring_submit_unlock(ctx, issue_flags);
+	return file;
+}
+
+static struct file *io_file_get_normal(struct io_kiocb *req, int fd)
+{
+	struct file *file = fget(fd);
+
+	trace_io_uring_file_get(req->ctx, req, req->cqe.user_data, fd);
+
+	/* we don't allow fixed io_uring files */
+	if (file && file->f_op == &io_uring_fops)
+		io_req_track_inflight(req);
+	return file;
+}
+
+static void io_req_task_link_timeout(struct io_kiocb *req, bool *locked)
+{
+	struct io_kiocb *prev = req->timeout.prev;
+	int ret = -ENOENT;
+
+	if (prev) {
+		if (!(req->task->flags & PF_EXITING)) {
+			struct io_cancel_data cd = {
+				.ctx		= req->ctx,
+				.data		= prev->cqe.user_data,
+			};
+
+			ret = io_try_cancel(req, &cd);
+		}
+		io_req_complete_post(req, ret ?: -ETIME, 0);
+		io_put_req(prev);
+	} else {
+		io_req_complete_post(req, -ETIME, 0);
+	}
+}
+
+static enum hrtimer_restart io_link_timeout_fn(struct hrtimer *timer)
+{
+	struct io_timeout_data *data = container_of(timer,
+						struct io_timeout_data, timer);
+	struct io_kiocb *prev, *req = data->req;
+	struct io_ring_ctx *ctx = req->ctx;
+	unsigned long flags;
+
+	spin_lock_irqsave(&ctx->timeout_lock, flags);
+	prev = req->timeout.head;
+	req->timeout.head = NULL;
+
+	/*
+	 * We don't expect the list to be empty, that will only happen if we
+	 * race with the completion of the linked work.
+	 */
+	if (prev) {
+		io_remove_next_linked(prev);
+		if (!req_ref_inc_not_zero(prev))
+			prev = NULL;
+	}
+	list_del(&req->timeout.list);
+	req->timeout.prev = prev;
+	spin_unlock_irqrestore(&ctx->timeout_lock, flags);
+
+	req->io_task_work.func = io_req_task_link_timeout;
+	io_req_task_work_add(req);
+	return HRTIMER_NORESTART;
+}
+
+static void io_queue_linked_timeout(struct io_kiocb *req)
+{
+	struct io_ring_ctx *ctx = req->ctx;
+
+	spin_lock_irq(&ctx->timeout_lock);
+	/*
+	 * If the back reference is NULL, then our linked request finished
+	 * before we got a chance to setup the timer
+	 */
+	if (req->timeout.head) {
+		struct io_timeout_data *data = req->async_data;
+
+		data->timer.function = io_link_timeout_fn;
+		hrtimer_start(&data->timer, timespec64_to_ktime(data->ts),
+				data->mode);
+		list_add_tail(&req->timeout.list, &ctx->ltimeout_list);
+	}
+	spin_unlock_irq(&ctx->timeout_lock);
+	/* drop submission reference */
+	io_put_req(req);
+}
+
+static void io_queue_async(struct io_kiocb *req, int ret)
+	__must_hold(&req->ctx->uring_lock)
+{
+	struct io_kiocb *linked_timeout;
+
+	if (ret != -EAGAIN || (req->flags & REQ_F_NOWAIT)) {
+		io_req_complete_failed(req, ret);
+		return;
+	}
+
+	linked_timeout = io_prep_linked_timeout(req);
+
+	switch (io_arm_poll_handler(req, 0)) {
+	case IO_APOLL_READY:
+		io_req_task_queue(req);
+		break;
+	case IO_APOLL_ABORTED:
+		/*
+		 * Queued up for async execution, worker will release
+		 * submit reference when the iocb is actually submitted.
+		 */
+		io_kbuf_recycle(req, 0);
+		io_queue_iowq(req, NULL);
+		break;
+	case IO_APOLL_OK:
+		break;
+	}
+
+	if (linked_timeout)
+		io_queue_linked_timeout(linked_timeout);
+}
+
+static inline void io_queue_sqe(struct io_kiocb *req)
+	__must_hold(&req->ctx->uring_lock)
+{
+	int ret;
+
+	ret = io_issue_sqe(req, IO_URING_F_NONBLOCK|IO_URING_F_COMPLETE_DEFER);
+
+	if (req->flags & REQ_F_COMPLETE_INLINE) {
+		io_req_add_compl_list(req);
+		return;
+	}
+	/*
+	 * We async punt it if the file wasn't marked NOWAIT, or if the file
+	 * doesn't support non-blocking read/write attempts
+	 */
+	if (likely(!ret))
+		io_arm_ltimeout(req);
+	else
+		io_queue_async(req, ret);
+}
+
+static void io_queue_sqe_fallback(struct io_kiocb *req)
+	__must_hold(&req->ctx->uring_lock)
+{
+	if (unlikely(req->flags & REQ_F_FAIL)) {
+		/*
+		 * We don't submit, fail them all, for that replace hardlinks
+		 * with normal links. Extra REQ_F_LINK is tolerated.
+		 */
+		req->flags &= ~REQ_F_HARDLINK;
+		req->flags |= REQ_F_LINK;
+		io_req_complete_failed(req, req->cqe.res);
+	} else if (unlikely(req->ctx->drain_active)) {
+		io_drain_req(req);
+	} else {
+		int ret = io_req_prep_async(req);
+
+		if (unlikely(ret))
+			io_req_complete_failed(req, ret);
+		else
+			io_queue_iowq(req, NULL);
+	}
+}
+
+/*
+ * Check SQE restrictions (opcode and flags).
+ *
+ * Returns 'true' if SQE is allowed, 'false' otherwise.
+ */
+static inline bool io_check_restriction(struct io_ring_ctx *ctx,
+					struct io_kiocb *req,
+					unsigned int sqe_flags)
+{
+	if (!test_bit(req->opcode, ctx->restrictions.sqe_op))
+		return false;
+
+	if ((sqe_flags & ctx->restrictions.sqe_flags_required) !=
+	    ctx->restrictions.sqe_flags_required)
+		return false;
+
+	if (sqe_flags & ~(ctx->restrictions.sqe_flags_allowed |
+			  ctx->restrictions.sqe_flags_required))
+		return false;
+
+	return true;
+}
+
+static void io_init_req_drain(struct io_kiocb *req)
+{
+	struct io_ring_ctx *ctx = req->ctx;
+	struct io_kiocb *head = ctx->submit_state.link.head;
+
+	ctx->drain_active = true;
+	if (head) {
+		/*
+		 * If we need to drain a request in the middle of a link, drain
+		 * the head request and the next request/link after the current
+		 * link. Considering sequential execution of links,
+		 * REQ_F_IO_DRAIN will be maintained for every request of our
+		 * link.
+		 */
+		head->flags |= REQ_F_IO_DRAIN | REQ_F_FORCE_ASYNC;
+		ctx->drain_next = true;
+	}
+}
+
+static int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req,
+		       const struct io_uring_sqe *sqe)
+	__must_hold(&ctx->uring_lock)
+{
+	const struct io_op_def *def;
+	unsigned int sqe_flags;
+	int personality;
+	u8 opcode;
+
+	/* req is partially pre-initialised, see io_preinit_req() */
+	req->opcode = opcode = READ_ONCE(sqe->opcode);
+	/* same numerical values with corresponding REQ_F_*, safe to copy */
+	req->flags = sqe_flags = READ_ONCE(sqe->flags);
+	req->cqe.user_data = READ_ONCE(sqe->user_data);
+	req->file = NULL;
+	req->rsrc_node = NULL;
+	req->task = current;
+
+	if (unlikely(opcode >= IORING_OP_LAST)) {
+		req->opcode = 0;
+		return -EINVAL;
+	}
+	def = &io_op_defs[opcode];
+	if (unlikely(sqe_flags & ~SQE_COMMON_FLAGS)) {
+		/* enforce forwards compatibility on users */
+		if (sqe_flags & ~SQE_VALID_FLAGS)
+			return -EINVAL;
+		if (sqe_flags & IOSQE_BUFFER_SELECT) {
+			if (!def->buffer_select)
+				return -EOPNOTSUPP;
+			req->buf_index = READ_ONCE(sqe->buf_group);
+		}
+		if (sqe_flags & IOSQE_CQE_SKIP_SUCCESS)
+			ctx->drain_disabled = true;
+		if (sqe_flags & IOSQE_IO_DRAIN) {
+			if (ctx->drain_disabled)
+				return -EOPNOTSUPP;
+			io_init_req_drain(req);
+		}
+	}
+	if (unlikely(ctx->restricted || ctx->drain_active || ctx->drain_next)) {
+		if (ctx->restricted && !io_check_restriction(ctx, req, sqe_flags))
+			return -EACCES;
+		/* knock it to the slow queue path, will be drained there */
+		if (ctx->drain_active)
+			req->flags |= REQ_F_FORCE_ASYNC;
+		/* if there is no link, we're at "next" request and need to drain */
+		if (unlikely(ctx->drain_next) && !ctx->submit_state.link.head) {
+			ctx->drain_next = false;
+			ctx->drain_active = true;
+			req->flags |= REQ_F_IO_DRAIN | REQ_F_FORCE_ASYNC;
+		}
+	}
+
+	if (!def->ioprio && sqe->ioprio)
+		return -EINVAL;
+	if (!def->iopoll && (ctx->flags & IORING_SETUP_IOPOLL))
+		return -EINVAL;
+
+	if (def->needs_file) {
+		struct io_submit_state *state = &ctx->submit_state;
+
+		req->cqe.fd = READ_ONCE(sqe->fd);
+
+		/*
+		 * Plug now if we have more than 2 IO left after this, and the
+		 * target is potentially a read/write to block based storage.
+		 */
+		if (state->need_plug && def->plug) {
+			state->plug_started = true;
+			state->need_plug = false;
+			blk_start_plug_nr_ios(&state->plug, state->submit_nr);
+		}
+	}
+
+	personality = READ_ONCE(sqe->personality);
+	if (personality) {
+		int ret;
+
+		req->creds = xa_load(&ctx->personalities, personality);
+		if (!req->creds)
+			return -EINVAL;
+		get_cred(req->creds);
+		ret = security_uring_override_creds(req->creds);
+		if (ret) {
+			put_cred(req->creds);
+			return ret;
+		}
+		req->flags |= REQ_F_CREDS;
+	}
+
+	return def->prep(req, sqe);
+}
+
+static __cold int io_submit_fail_init(const struct io_uring_sqe *sqe,
+				      struct io_kiocb *req, int ret)
+{
+	struct io_ring_ctx *ctx = req->ctx;
+	struct io_submit_link *link = &ctx->submit_state.link;
+	struct io_kiocb *head = link->head;
+
+	trace_io_uring_req_failed(sqe, ctx, req, ret);
+
+	/*
+	 * Avoid breaking links in the middle as it renders links with SQPOLL
+	 * unusable. Instead of failing eagerly, continue assembling the link if
+	 * applicable and mark the head with REQ_F_FAIL. The link flushing code
+	 * should find the flag and handle the rest.
+	 */
+	req_fail_link_node(req, ret);
+	if (head && !(head->flags & REQ_F_FAIL))
+		req_fail_link_node(head, -ECANCELED);
+
+	if (!(req->flags & IO_REQ_LINK_FLAGS)) {
+		if (head) {
+			link->last->link = req;
+			link->head = NULL;
+			req = head;
+		}
+		io_queue_sqe_fallback(req);
+		return ret;
+	}
+
+	if (head)
+		link->last->link = req;
+	else
+		link->head = req;
+	link->last = req;
+	return 0;
+}
+
+static inline int io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req,
+			 const struct io_uring_sqe *sqe)
+	__must_hold(&ctx->uring_lock)
+{
+	struct io_submit_link *link = &ctx->submit_state.link;
+	int ret;
+
+	ret = io_init_req(ctx, req, sqe);
+	if (unlikely(ret))
+		return io_submit_fail_init(sqe, req, ret);
+
+	/* don't need @sqe from now on */
+	trace_io_uring_submit_sqe(ctx, req, req->cqe.user_data, req->opcode,
+				  req->flags, true,
+				  ctx->flags & IORING_SETUP_SQPOLL);
+
+	/*
+	 * If we already have a head request, queue this one for async
+	 * submittal once the head completes. If we don't have a head but
+	 * IOSQE_IO_LINK is set in the sqe, start a new head. This one will be
+	 * submitted sync once the chain is complete. If none of those
+	 * conditions are true (normal request), then just queue it.
+	 */
+	if (unlikely(link->head)) {
+		ret = io_req_prep_async(req);
+		if (unlikely(ret))
+			return io_submit_fail_init(sqe, req, ret);
+
+		trace_io_uring_link(ctx, req, link->head);
+		link->last->link = req;
+		link->last = req;
+
+		if (req->flags & IO_REQ_LINK_FLAGS)
+			return 0;
+		/* last request of the link, flush it */
+		req = link->head;
+		link->head = NULL;
+		if (req->flags & (REQ_F_FORCE_ASYNC | REQ_F_FAIL))
+			goto fallback;
+
+	} else if (unlikely(req->flags & (IO_REQ_LINK_FLAGS |
+					  REQ_F_FORCE_ASYNC | REQ_F_FAIL))) {
+		if (req->flags & IO_REQ_LINK_FLAGS) {
+			link->head = req;
+			link->last = req;
+		} else {
+fallback:
+			io_queue_sqe_fallback(req);
+		}
+		return 0;
+	}
+
+	io_queue_sqe(req);
+	return 0;
+}
+
+/*
+ * Batched submission is done, ensure local IO is flushed out.
+ */
+static void io_submit_state_end(struct io_ring_ctx *ctx)
+{
+	struct io_submit_state *state = &ctx->submit_state;
+
+	if (unlikely(state->link.head))
+		io_queue_sqe_fallback(state->link.head);
+	/* flush only after queuing links as they can generate completions */
+	io_submit_flush_completions(ctx);
+	if (state->plug_started)
+		blk_finish_plug(&state->plug);
+}
+
+/*
+ * Start submission side cache.
+ */
+static void io_submit_state_start(struct io_submit_state *state,
+				  unsigned int max_ios)
+{
+	state->plug_started = false;
+	state->need_plug = max_ios > 2;
+	state->submit_nr = max_ios;
+	/* set only head, no need to init link_last in advance */
+	state->link.head = NULL;
+}
+
+static void io_commit_sqring(struct io_ring_ctx *ctx)
+{
+	struct io_rings *rings = ctx->rings;
+
+	/*
+	 * Ensure any loads from the SQEs are done at this point,
+	 * since once we write the new head, the application could
+	 * write new data to them.
+	 */
+	smp_store_release(&rings->sq.head, ctx->cached_sq_head);
+}
+
+/*
+ * Fetch an sqe, if one is available. Note this returns a pointer to memory
+ * that is mapped by userspace. This means that care needs to be taken to
+ * ensure that reads are stable, as we cannot rely on userspace always
+ * being a good citizen. If members of the sqe are validated and then later
+ * used, it's important that those reads are done through READ_ONCE() to
+ * prevent a re-load down the line.
+ */
+static const struct io_uring_sqe *io_get_sqe(struct io_ring_ctx *ctx)
+{
+	unsigned head, mask = ctx->sq_entries - 1;
+	unsigned sq_idx = ctx->cached_sq_head++ & mask;
+
+	/*
+	 * The cached sq head (or cq tail) serves two purposes:
+	 *
+	 * 1) allows us to batch the cost of updating the user visible
+	 *    head updates.
+	 * 2) allows the kernel side to track the head on its own, even
+	 *    though the application is the one updating it.
+	 */
+	head = READ_ONCE(ctx->sq_array[sq_idx]);
+	if (likely(head < ctx->sq_entries)) {
+		/* double index for 128-byte SQEs, twice as long */
+		if (ctx->flags & IORING_SETUP_SQE128)
+			head <<= 1;
+		return &ctx->sq_sqes[head];
+	}
+
+	/* drop invalid entries */
+	ctx->cq_extra--;
+	WRITE_ONCE(ctx->rings->sq_dropped,
+		   READ_ONCE(ctx->rings->sq_dropped) + 1);
+	return NULL;
+}
+
+static int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr)
+	__must_hold(&ctx->uring_lock)
+{
+	unsigned int entries = io_sqring_entries(ctx);
+	unsigned int left;
+	int ret;
+
+	if (unlikely(!entries))
+		return 0;
+	/* make sure SQ entry isn't read before tail */
+	ret = left = min3(nr, ctx->sq_entries, entries);
+	io_get_task_refs(left);
+	io_submit_state_start(&ctx->submit_state, left);
+
+	do {
+		const struct io_uring_sqe *sqe;
+		struct io_kiocb *req;
+
+		if (unlikely(!io_alloc_req_refill(ctx)))
+			break;
+		req = io_alloc_req(ctx);
+		sqe = io_get_sqe(ctx);
+		if (unlikely(!sqe)) {
+			io_req_add_to_cache(req, ctx);
+			break;
+		}
+
+		/*
+		 * Continue submitting even for sqe failure if the
+		 * ring was setup with IORING_SETUP_SUBMIT_ALL
+		 */
+		if (unlikely(io_submit_sqe(ctx, req, sqe)) &&
+		    !(ctx->flags & IORING_SETUP_SUBMIT_ALL)) {
+			left--;
+			break;
+		}
+	} while (--left);
+
+	if (unlikely(left)) {
+		ret -= left;
+		/* try again if it submitted nothing and can't allocate a req */
+		if (!ret && io_req_cache_empty(ctx))
+			ret = -EAGAIN;
+		current->io_uring->cached_refs += left;
+	}
+
+	io_submit_state_end(ctx);
+	 /* Commit SQ ring head once we've consumed and submitted all SQEs */
+	io_commit_sqring(ctx);
+	return ret;
+}
+
+static inline bool io_sqd_events_pending(struct io_sq_data *sqd)
+{
+	return READ_ONCE(sqd->state);
+}
+
+static int __io_sq_thread(struct io_ring_ctx *ctx, bool cap_entries)
+{
+	unsigned int to_submit;
+	int ret = 0;
+
+	to_submit = io_sqring_entries(ctx);
+	/* if we're handling multiple rings, cap submit size for fairness */
+	if (cap_entries && to_submit > IORING_SQPOLL_CAP_ENTRIES_VALUE)
+		to_submit = IORING_SQPOLL_CAP_ENTRIES_VALUE;
+
+	if (!wq_list_empty(&ctx->iopoll_list) || to_submit) {
+		const struct cred *creds = NULL;
+
+		if (ctx->sq_creds != current_cred())
+			creds = override_creds(ctx->sq_creds);
+
+		mutex_lock(&ctx->uring_lock);
+		if (!wq_list_empty(&ctx->iopoll_list))
+			io_do_iopoll(ctx, true);
+
+		/*
+		 * Don't submit if refs are dying, good for io_uring_register(),
+		 * but also it is relied upon by io_ring_exit_work()
+		 */
+		if (to_submit && likely(!percpu_ref_is_dying(&ctx->refs)) &&
+		    !(ctx->flags & IORING_SETUP_R_DISABLED))
+			ret = io_submit_sqes(ctx, to_submit);
+		mutex_unlock(&ctx->uring_lock);
+
+		if (to_submit && wq_has_sleeper(&ctx->sqo_sq_wait))
+			wake_up(&ctx->sqo_sq_wait);
+		if (creds)
+			revert_creds(creds);
+	}
+
+	return ret;
+}
+
+static __cold void io_sqd_update_thread_idle(struct io_sq_data *sqd)
+{
+	struct io_ring_ctx *ctx;
+	unsigned sq_thread_idle = 0;
+
+	list_for_each_entry(ctx, &sqd->ctx_list, sqd_list)
+		sq_thread_idle = max(sq_thread_idle, ctx->sq_thread_idle);
+	sqd->sq_thread_idle = sq_thread_idle;
+}
+
+static bool io_sqd_handle_event(struct io_sq_data *sqd)
+{
+	bool did_sig = false;
+	struct ksignal ksig;
+
+	if (test_bit(IO_SQ_THREAD_SHOULD_PARK, &sqd->state) ||
+	    signal_pending(current)) {
+		mutex_unlock(&sqd->lock);
+		if (signal_pending(current))
+			did_sig = get_signal(&ksig);
+		cond_resched();
+		mutex_lock(&sqd->lock);
+	}
+	return did_sig || test_bit(IO_SQ_THREAD_SHOULD_STOP, &sqd->state);
+}
+
+static int io_sq_thread(void *data)
+{
+	struct io_sq_data *sqd = data;
+	struct io_ring_ctx *ctx;
+	unsigned long timeout = 0;
+	char buf[TASK_COMM_LEN];
+	DEFINE_WAIT(wait);
+
+	snprintf(buf, sizeof(buf), "iou-sqp-%d", sqd->task_pid);
+	set_task_comm(current, buf);
+
+	if (sqd->sq_cpu != -1)
+		set_cpus_allowed_ptr(current, cpumask_of(sqd->sq_cpu));
+	else
+		set_cpus_allowed_ptr(current, cpu_online_mask);
+	current->flags |= PF_NO_SETAFFINITY;
+
+	audit_alloc_kernel(current);
+
+	mutex_lock(&sqd->lock);
+	while (1) {
+		bool cap_entries, sqt_spin = false;
+
+		if (io_sqd_events_pending(sqd) || signal_pending(current)) {
+			if (io_sqd_handle_event(sqd))
+				break;
+			timeout = jiffies + sqd->sq_thread_idle;
+		}
+
+		cap_entries = !list_is_singular(&sqd->ctx_list);
+		list_for_each_entry(ctx, &sqd->ctx_list, sqd_list) {
+			int ret = __io_sq_thread(ctx, cap_entries);
+
+			if (!sqt_spin && (ret > 0 || !wq_list_empty(&ctx->iopoll_list)))
+				sqt_spin = true;
+		}
+		if (io_run_task_work())
+			sqt_spin = true;
+
+		if (sqt_spin || !time_after(jiffies, timeout)) {
+			cond_resched();
+			if (sqt_spin)
+				timeout = jiffies + sqd->sq_thread_idle;
+			continue;
+		}
+
+		prepare_to_wait(&sqd->wait, &wait, TASK_INTERRUPTIBLE);
+		if (!io_sqd_events_pending(sqd) && !task_work_pending(current)) {
+			bool needs_sched = true;
+
+			list_for_each_entry(ctx, &sqd->ctx_list, sqd_list) {
+				atomic_or(IORING_SQ_NEED_WAKEUP,
+						&ctx->rings->sq_flags);
+				if ((ctx->flags & IORING_SETUP_IOPOLL) &&
+				    !wq_list_empty(&ctx->iopoll_list)) {
+					needs_sched = false;
+					break;
+				}
+
+				/*
+				 * Ensure the store of the wakeup flag is not
+				 * reordered with the load of the SQ tail
+				 */
+				smp_mb__after_atomic();
+
+				if (io_sqring_entries(ctx)) {
+					needs_sched = false;
+					break;
+				}
+			}
+
+			if (needs_sched) {
+				mutex_unlock(&sqd->lock);
+				schedule();
+				mutex_lock(&sqd->lock);
+			}
+			list_for_each_entry(ctx, &sqd->ctx_list, sqd_list)
+				atomic_andnot(IORING_SQ_NEED_WAKEUP,
+						&ctx->rings->sq_flags);
+		}
+
+		finish_wait(&sqd->wait, &wait);
+		timeout = jiffies + sqd->sq_thread_idle;
+	}
+
+	io_uring_cancel_generic(true, sqd);
+	sqd->thread = NULL;
+	list_for_each_entry(ctx, &sqd->ctx_list, sqd_list)
+		atomic_or(IORING_SQ_NEED_WAKEUP, &ctx->rings->sq_flags);
+	io_run_task_work();
+	mutex_unlock(&sqd->lock);
+
+	audit_free(current);
+
+	complete(&sqd->exited);
+	do_exit(0);
+}
+
+struct io_wait_queue {
+	struct wait_queue_entry wq;
+	struct io_ring_ctx *ctx;
+	unsigned cq_tail;
+	unsigned nr_timeouts;
+};
+
+static inline bool io_should_wake(struct io_wait_queue *iowq)
+{
+	struct io_ring_ctx *ctx = iowq->ctx;
+	int dist = ctx->cached_cq_tail - (int) iowq->cq_tail;
+
+	/*
+	 * Wake up if we have enough events, or if a timeout occurred since we
+	 * started waiting. For timeouts, we always want to return to userspace,
+	 * regardless of event count.
+	 */
+	return dist >= 0 || atomic_read(&ctx->cq_timeouts) != iowq->nr_timeouts;
+}
+
+static int io_wake_function(struct wait_queue_entry *curr, unsigned int mode,
+			    int wake_flags, void *key)
+{
+	struct io_wait_queue *iowq = container_of(curr, struct io_wait_queue,
+							wq);
+
+	/*
+	 * Cannot safely flush overflowed CQEs from here, ensure we wake up
+	 * the task, and the next invocation will do it.
+	 */
+	if (io_should_wake(iowq) ||
+	    test_bit(IO_CHECK_CQ_OVERFLOW_BIT, &iowq->ctx->check_cq))
+		return autoremove_wake_function(curr, mode, wake_flags, key);
+	return -1;
+}
+
+static int io_run_task_work_sig(void)
+{
+	if (io_run_task_work())
+		return 1;
+	if (test_thread_flag(TIF_NOTIFY_SIGNAL))
+		return -ERESTARTSYS;
+	if (task_sigpending(current))
+		return -EINTR;
+	return 0;
+}
+
+/* when returns >0, the caller should retry */
+static inline int io_cqring_wait_schedule(struct io_ring_ctx *ctx,
+					  struct io_wait_queue *iowq,
+					  ktime_t timeout)
+{
+	int ret;
+	unsigned long check_cq;
+
+	/* make sure we run task_work before checking for signals */
+	ret = io_run_task_work_sig();
+	if (ret || io_should_wake(iowq))
+		return ret;
+	check_cq = READ_ONCE(ctx->check_cq);
+	/* let the caller flush overflows, retry */
+	if (check_cq & BIT(IO_CHECK_CQ_OVERFLOW_BIT))
+		return 1;
+	if (unlikely(check_cq & BIT(IO_CHECK_CQ_DROPPED_BIT)))
+		return -EBADR;
+	if (!schedule_hrtimeout(&timeout, HRTIMER_MODE_ABS))
+		return -ETIME;
+	return 1;
+}
+
+/*
+ * Wait until events become available, if we don't already have some. The
+ * application must reap them itself, as they reside on the shared cq ring.
+ */
+static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events,
+			  const sigset_t __user *sig, size_t sigsz,
+			  struct __kernel_timespec __user *uts)
+{
+	struct io_wait_queue iowq;
+	struct io_rings *rings = ctx->rings;
+	ktime_t timeout = KTIME_MAX;
+	int ret;
+
+	do {
+		io_cqring_overflow_flush(ctx);
+		if (io_cqring_events(ctx) >= min_events)
+			return 0;
+		if (!io_run_task_work())
+			break;
+	} while (1);
+
+	if (sig) {
+#ifdef CONFIG_COMPAT
+		if (in_compat_syscall())
+			ret = set_compat_user_sigmask((const compat_sigset_t __user *)sig,
+						      sigsz);
+		else
+#endif
+			ret = set_user_sigmask(sig, sigsz);
+
+		if (ret)
+			return ret;
+	}
+
+	if (uts) {
+		struct timespec64 ts;
+
+		if (get_timespec64(&ts, uts))
+			return -EFAULT;
+		timeout = ktime_add_ns(timespec64_to_ktime(ts), ktime_get_ns());
+	}
+
+	init_waitqueue_func_entry(&iowq.wq, io_wake_function);
+	iowq.wq.private = current;
+	INIT_LIST_HEAD(&iowq.wq.entry);
+	iowq.ctx = ctx;
+	iowq.nr_timeouts = atomic_read(&ctx->cq_timeouts);
+	iowq.cq_tail = READ_ONCE(ctx->rings->cq.head) + min_events;
+
+	trace_io_uring_cqring_wait(ctx, min_events);
+	do {
+		/* if we can't even flush overflow, don't wait for more */
+		if (!io_cqring_overflow_flush(ctx)) {
+			ret = -EBUSY;
+			break;
+		}
+		prepare_to_wait_exclusive(&ctx->cq_wait, &iowq.wq,
+						TASK_INTERRUPTIBLE);
+		ret = io_cqring_wait_schedule(ctx, &iowq, timeout);
+		cond_resched();
+	} while (ret > 0);
+
+	finish_wait(&ctx->cq_wait, &iowq.wq);
+	restore_saved_sigmask_unless(ret == -EINTR);
+
+	return READ_ONCE(rings->cq.head) == READ_ONCE(rings->cq.tail) ? ret : 0;
+}
+
+static void io_free_page_table(void **table, size_t size)
+{
+	unsigned i, nr_tables = DIV_ROUND_UP(size, PAGE_SIZE);
+
+	for (i = 0; i < nr_tables; i++)
+		kfree(table[i]);
+	kfree(table);
+}
+
+static __cold void **io_alloc_page_table(size_t size)
+{
+	unsigned i, nr_tables = DIV_ROUND_UP(size, PAGE_SIZE);
+	size_t init_size = size;
+	void **table;
+
+	table = kcalloc(nr_tables, sizeof(*table), GFP_KERNEL_ACCOUNT);
+	if (!table)
+		return NULL;
+
+	for (i = 0; i < nr_tables; i++) {
+		unsigned int this_size = min_t(size_t, size, PAGE_SIZE);
+
+		table[i] = kzalloc(this_size, GFP_KERNEL_ACCOUNT);
+		if (!table[i]) {
+			io_free_page_table(table, init_size);
+			return NULL;
+		}
+		size -= this_size;
+	}
+	return table;
+}
+
+static void io_rsrc_node_destroy(struct io_rsrc_node *ref_node)
+{
+	percpu_ref_exit(&ref_node->refs);
+	kfree(ref_node);
+}
+
+static __cold void io_rsrc_node_ref_zero(struct percpu_ref *ref)
+{
+	struct io_rsrc_node *node = container_of(ref, struct io_rsrc_node, refs);
+	struct io_ring_ctx *ctx = node->rsrc_data->ctx;
+	unsigned long flags;
+	bool first_add = false;
+	unsigned long delay = HZ;
+
+	spin_lock_irqsave(&ctx->rsrc_ref_lock, flags);
+	node->done = true;
+
+	/* if we are mid-quiesce then do not delay */
+	if (node->rsrc_data->quiesce)
+		delay = 0;
+
+	while (!list_empty(&ctx->rsrc_ref_list)) {
+		node = list_first_entry(&ctx->rsrc_ref_list,
+					    struct io_rsrc_node, node);
+		/* recycle ref nodes in order */
+		if (!node->done)
+			break;
+		list_del(&node->node);
+		first_add |= llist_add(&node->llist, &ctx->rsrc_put_llist);
+	}
+	spin_unlock_irqrestore(&ctx->rsrc_ref_lock, flags);
+
+	if (first_add)
+		mod_delayed_work(system_wq, &ctx->rsrc_put_work, delay);
+}
+
+static struct io_rsrc_node *io_rsrc_node_alloc(void)
+{
+	struct io_rsrc_node *ref_node;
+
+	ref_node = kzalloc(sizeof(*ref_node), GFP_KERNEL);
+	if (!ref_node)
+		return NULL;
+
+	if (percpu_ref_init(&ref_node->refs, io_rsrc_node_ref_zero,
+			    0, GFP_KERNEL)) {
+		kfree(ref_node);
+		return NULL;
+	}
+	INIT_LIST_HEAD(&ref_node->node);
+	INIT_LIST_HEAD(&ref_node->rsrc_list);
+	ref_node->done = false;
+	return ref_node;
+}
+
+static void io_rsrc_node_switch(struct io_ring_ctx *ctx,
+				struct io_rsrc_data *data_to_kill)
+	__must_hold(&ctx->uring_lock)
+{
+	WARN_ON_ONCE(!ctx->rsrc_backup_node);
+	WARN_ON_ONCE(data_to_kill && !ctx->rsrc_node);
+
+	io_rsrc_refs_drop(ctx);
+
+	if (data_to_kill) {
+		struct io_rsrc_node *rsrc_node = ctx->rsrc_node;
+
+		rsrc_node->rsrc_data = data_to_kill;
+		spin_lock_irq(&ctx->rsrc_ref_lock);
+		list_add_tail(&rsrc_node->node, &ctx->rsrc_ref_list);
+		spin_unlock_irq(&ctx->rsrc_ref_lock);
+
+		atomic_inc(&data_to_kill->refs);
+		percpu_ref_kill(&rsrc_node->refs);
+		ctx->rsrc_node = NULL;
+	}
+
+	if (!ctx->rsrc_node) {
+		ctx->rsrc_node = ctx->rsrc_backup_node;
+		ctx->rsrc_backup_node = NULL;
+	}
+}
+
+static int io_rsrc_node_switch_start(struct io_ring_ctx *ctx)
+{
+	if (ctx->rsrc_backup_node)
+		return 0;
+	ctx->rsrc_backup_node = io_rsrc_node_alloc();
+	return ctx->rsrc_backup_node ? 0 : -ENOMEM;
+}
+
+static __cold int io_rsrc_ref_quiesce(struct io_rsrc_data *data,
+				      struct io_ring_ctx *ctx)
+{
+	int ret;
+
+	/* As we may drop ->uring_lock, other task may have started quiesce */
+	if (data->quiesce)
+		return -ENXIO;
+
+	data->quiesce = true;
+	do {
+		ret = io_rsrc_node_switch_start(ctx);
+		if (ret)
+			break;
+		io_rsrc_node_switch(ctx, data);
+
+		/* kill initial ref, already quiesced if zero */
+		if (atomic_dec_and_test(&data->refs))
+			break;
+		mutex_unlock(&ctx->uring_lock);
+		flush_delayed_work(&ctx->rsrc_put_work);
+		ret = wait_for_completion_interruptible(&data->done);
+		if (!ret) {
+			mutex_lock(&ctx->uring_lock);
+			if (atomic_read(&data->refs) > 0) {
+				/*
+				 * it has been revived by another thread while
+				 * we were unlocked
+				 */
+				mutex_unlock(&ctx->uring_lock);
+			} else {
+				break;
+			}
+		}
+
+		atomic_inc(&data->refs);
+		/* wait for all works potentially completing data->done */
+		flush_delayed_work(&ctx->rsrc_put_work);
+		reinit_completion(&data->done);
+
+		ret = io_run_task_work_sig();
+		mutex_lock(&ctx->uring_lock);
+	} while (ret >= 0);
+	data->quiesce = false;
+
+	return ret;
+}
+
+static u64 *io_get_tag_slot(struct io_rsrc_data *data, unsigned int idx)
+{
+	unsigned int off = idx & IO_RSRC_TAG_TABLE_MASK;
+	unsigned int table_idx = idx >> IO_RSRC_TAG_TABLE_SHIFT;
+
+	return &data->tags[table_idx][off];
+}
+
+static void io_rsrc_data_free(struct io_rsrc_data *data)
+{
+	size_t size = data->nr * sizeof(data->tags[0][0]);
+
+	if (data->tags)
+		io_free_page_table((void **)data->tags, size);
+	kfree(data);
+}
+
+static __cold int io_rsrc_data_alloc(struct io_ring_ctx *ctx, rsrc_put_fn *do_put,
+				     u64 __user *utags, unsigned nr,
+				     struct io_rsrc_data **pdata)
+{
+	struct io_rsrc_data *data;
+	int ret = -ENOMEM;
+	unsigned i;
+
+	data = kzalloc(sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+	data->tags = (u64 **)io_alloc_page_table(nr * sizeof(data->tags[0][0]));
+	if (!data->tags) {
+		kfree(data);
+		return -ENOMEM;
+	}
+
+	data->nr = nr;
+	data->ctx = ctx;
+	data->do_put = do_put;
+	if (utags) {
+		ret = -EFAULT;
+		for (i = 0; i < nr; i++) {
+			u64 *tag_slot = io_get_tag_slot(data, i);
+
+			if (copy_from_user(tag_slot, &utags[i],
+					   sizeof(*tag_slot)))
+				goto fail;
+		}
+	}
+
+	atomic_set(&data->refs, 1);
+	init_completion(&data->done);
+	*pdata = data;
+	return 0;
+fail:
+	io_rsrc_data_free(data);
+	return ret;
+}
+
+static bool io_alloc_file_tables(struct io_file_table *table, unsigned nr_files)
+{
+	table->files = kvcalloc(nr_files, sizeof(table->files[0]),
+				GFP_KERNEL_ACCOUNT);
+	if (unlikely(!table->files))
+		return false;
+
+	table->bitmap = bitmap_zalloc(nr_files, GFP_KERNEL_ACCOUNT);
+	if (unlikely(!table->bitmap)) {
+		kvfree(table->files);
+		return false;
+	}
+
+	return true;
+}
+
+static void io_free_file_tables(struct io_file_table *table)
+{
+	kvfree(table->files);
+	bitmap_free(table->bitmap);
+	table->files = NULL;
+	table->bitmap = NULL;
+}
+
+static inline void io_file_bitmap_set(struct io_file_table *table, int bit)
+{
+	WARN_ON_ONCE(test_bit(bit, table->bitmap));
+	__set_bit(bit, table->bitmap);
+	table->alloc_hint = bit + 1;
+}
+
+static inline void io_file_bitmap_clear(struct io_file_table *table, int bit)
+{
+	__clear_bit(bit, table->bitmap);
+	table->alloc_hint = bit;
+}
+
+static void __io_sqe_files_unregister(struct io_ring_ctx *ctx)
+{
+#if !defined(IO_URING_SCM_ALL)
+	int i;
+
+	for (i = 0; i < ctx->nr_user_files; i++) {
+		struct file *file = io_file_from_index(ctx, i);
+
+		if (!file)
+			continue;
+		if (io_fixed_file_slot(&ctx->file_table, i)->file_ptr & FFS_SCM)
+			continue;
+		io_file_bitmap_clear(&ctx->file_table, i);
+		fput(file);
+	}
+#endif
+
+#if defined(CONFIG_UNIX)
+	if (ctx->ring_sock) {
+		struct sock *sock = ctx->ring_sock->sk;
+		struct sk_buff *skb;
+
+		while ((skb = skb_dequeue(&sock->sk_receive_queue)) != NULL)
+			kfree_skb(skb);
+	}
+#endif
+	io_free_file_tables(&ctx->file_table);
+	io_rsrc_data_free(ctx->file_data);
+	ctx->file_data = NULL;
+	ctx->nr_user_files = 0;
+}
+
+static int io_sqe_files_unregister(struct io_ring_ctx *ctx)
+{
+	unsigned nr = ctx->nr_user_files;
+	int ret;
+
+	if (!ctx->file_data)
+		return -ENXIO;
+
+	/*
+	 * Quiesce may unlock ->uring_lock, and while it's not held
+	 * prevent new requests using the table.
+	 */
+	ctx->nr_user_files = 0;
+	ret = io_rsrc_ref_quiesce(ctx->file_data, ctx);
+	ctx->nr_user_files = nr;
+	if (!ret)
+		__io_sqe_files_unregister(ctx);
+	return ret;
+}
+
+static void io_sq_thread_unpark(struct io_sq_data *sqd)
+	__releases(&sqd->lock)
+{
+	WARN_ON_ONCE(sqd->thread == current);
+
+	/*
+	 * Do the dance but not conditional clear_bit() because it'd race with
+	 * other threads incrementing park_pending and setting the bit.
+	 */
+	clear_bit(IO_SQ_THREAD_SHOULD_PARK, &sqd->state);
+	if (atomic_dec_return(&sqd->park_pending))
+		set_bit(IO_SQ_THREAD_SHOULD_PARK, &sqd->state);
+	mutex_unlock(&sqd->lock);
+}
+
+static void io_sq_thread_park(struct io_sq_data *sqd)
+	__acquires(&sqd->lock)
+{
+	WARN_ON_ONCE(sqd->thread == current);
+
+	atomic_inc(&sqd->park_pending);
+	set_bit(IO_SQ_THREAD_SHOULD_PARK, &sqd->state);
+	mutex_lock(&sqd->lock);
+	if (sqd->thread)
+		wake_up_process(sqd->thread);
+}
+
+static void io_sq_thread_stop(struct io_sq_data *sqd)
+{
+	WARN_ON_ONCE(sqd->thread == current);
+	WARN_ON_ONCE(test_bit(IO_SQ_THREAD_SHOULD_STOP, &sqd->state));
+
+	set_bit(IO_SQ_THREAD_SHOULD_STOP, &sqd->state);
+	mutex_lock(&sqd->lock);
+	if (sqd->thread)
+		wake_up_process(sqd->thread);
+	mutex_unlock(&sqd->lock);
+	wait_for_completion(&sqd->exited);
+}
+
+static void io_put_sq_data(struct io_sq_data *sqd)
+{
+	if (refcount_dec_and_test(&sqd->refs)) {
+		WARN_ON_ONCE(atomic_read(&sqd->park_pending));
+
+		io_sq_thread_stop(sqd);
+		kfree(sqd);
+	}
+}
+
+static void io_sq_thread_finish(struct io_ring_ctx *ctx)
+{
+	struct io_sq_data *sqd = ctx->sq_data;
+
+	if (sqd) {
+		io_sq_thread_park(sqd);
+		list_del_init(&ctx->sqd_list);
+		io_sqd_update_thread_idle(sqd);
+		io_sq_thread_unpark(sqd);
+
+		io_put_sq_data(sqd);
+		ctx->sq_data = NULL;
+	}
+}
+
+static struct io_sq_data *io_attach_sq_data(struct io_uring_params *p)
+{
+	struct io_ring_ctx *ctx_attach;
+	struct io_sq_data *sqd;
+	struct fd f;
+
+	f = fdget(p->wq_fd);
+	if (!f.file)
+		return ERR_PTR(-ENXIO);
+	if (f.file->f_op != &io_uring_fops) {
+		fdput(f);
+		return ERR_PTR(-EINVAL);
+	}
+
+	ctx_attach = f.file->private_data;
+	sqd = ctx_attach->sq_data;
+	if (!sqd) {
+		fdput(f);
+		return ERR_PTR(-EINVAL);
+	}
+	if (sqd->task_tgid != current->tgid) {
+		fdput(f);
+		return ERR_PTR(-EPERM);
+	}
+
+	refcount_inc(&sqd->refs);
+	fdput(f);
+	return sqd;
+}
+
+static struct io_sq_data *io_get_sq_data(struct io_uring_params *p,
+					 bool *attached)
+{
+	struct io_sq_data *sqd;
+
+	*attached = false;
+	if (p->flags & IORING_SETUP_ATTACH_WQ) {
+		sqd = io_attach_sq_data(p);
+		if (!IS_ERR(sqd)) {
+			*attached = true;
+			return sqd;
+		}
+		/* fall through for EPERM case, setup new sqd/task */
+		if (PTR_ERR(sqd) != -EPERM)
+			return sqd;
+	}
+
+	sqd = kzalloc(sizeof(*sqd), GFP_KERNEL);
+	if (!sqd)
+		return ERR_PTR(-ENOMEM);
+
+	atomic_set(&sqd->park_pending, 0);
+	refcount_set(&sqd->refs, 1);
+	INIT_LIST_HEAD(&sqd->ctx_list);
+	mutex_init(&sqd->lock);
+	init_waitqueue_head(&sqd->wait);
+	init_completion(&sqd->exited);
+	return sqd;
+}
+
+/*
+ * Ensure the UNIX gc is aware of our file set, so we are certain that
+ * the io_uring can be safely unregistered on process exit, even if we have
+ * loops in the file referencing. We account only files that can hold other
+ * files because otherwise they can't form a loop and so are not interesting
+ * for GC.
+ */
+static int io_scm_file_account(struct io_ring_ctx *ctx, struct file *file)
+{
+#if defined(CONFIG_UNIX)
+	struct sock *sk = ctx->ring_sock->sk;
+	struct sk_buff_head *head = &sk->sk_receive_queue;
+	struct scm_fp_list *fpl;
+	struct sk_buff *skb;
+
+	if (likely(!io_file_need_scm(file)))
+		return 0;
+
+	/*
+	 * See if we can merge this file into an existing skb SCM_RIGHTS
+	 * file set. If there's no room, fall back to allocating a new skb
+	 * and filling it in.
+	 */
+	spin_lock_irq(&head->lock);
+	skb = skb_peek(head);
+	if (skb && UNIXCB(skb).fp->count < SCM_MAX_FD)
+		__skb_unlink(skb, head);
+	else
+		skb = NULL;
+	spin_unlock_irq(&head->lock);
+
+	if (!skb) {
+		fpl = kzalloc(sizeof(*fpl), GFP_KERNEL);
+		if (!fpl)
+			return -ENOMEM;
+
+		skb = alloc_skb(0, GFP_KERNEL);
+		if (!skb) {
+			kfree(fpl);
+			return -ENOMEM;
+		}
+
+		fpl->user = get_uid(current_user());
+		fpl->max = SCM_MAX_FD;
+		fpl->count = 0;
+
+		UNIXCB(skb).fp = fpl;
+		skb->sk = sk;
+		skb->destructor = unix_destruct_scm;
+		refcount_add(skb->truesize, &sk->sk_wmem_alloc);
+	}
+
+	fpl = UNIXCB(skb).fp;
+	fpl->fp[fpl->count++] = get_file(file);
+	unix_inflight(fpl->user, file);
+	skb_queue_head(head, skb);
+	fput(file);
+#endif
+	return 0;
+}
+
+static void io_rsrc_file_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc)
+{
+	struct file *file = prsrc->file;
+#if defined(CONFIG_UNIX)
+	struct sock *sock = ctx->ring_sock->sk;
+	struct sk_buff_head list, *head = &sock->sk_receive_queue;
+	struct sk_buff *skb;
+	int i;
+
+	if (!io_file_need_scm(file)) {
+		fput(file);
+		return;
+	}
+
+	__skb_queue_head_init(&list);
+
+	/*
+	 * Find the skb that holds this file in its SCM_RIGHTS. When found,
+	 * remove this entry and rearrange the file array.
+	 */
+	skb = skb_dequeue(head);
+	while (skb) {
+		struct scm_fp_list *fp;
+
+		fp = UNIXCB(skb).fp;
+		for (i = 0; i < fp->count; i++) {
+			int left;
+
+			if (fp->fp[i] != file)
+				continue;
+
+			unix_notinflight(fp->user, fp->fp[i]);
+			left = fp->count - 1 - i;
+			if (left) {
+				memmove(&fp->fp[i], &fp->fp[i + 1],
+						left * sizeof(struct file *));
+			}
+			fp->count--;
+			if (!fp->count) {
+				kfree_skb(skb);
+				skb = NULL;
+			} else {
+				__skb_queue_tail(&list, skb);
+			}
+			fput(file);
+			file = NULL;
+			break;
+		}
+
+		if (!file)
+			break;
+
+		__skb_queue_tail(&list, skb);
+
+		skb = skb_dequeue(head);
+	}
+
+	if (skb_peek(&list)) {
+		spin_lock_irq(&head->lock);
+		while ((skb = __skb_dequeue(&list)) != NULL)
+			__skb_queue_tail(head, skb);
+		spin_unlock_irq(&head->lock);
+	}
+#else
+	fput(file);
+#endif
+}
+
+static void __io_rsrc_put_work(struct io_rsrc_node *ref_node)
+{
+	struct io_rsrc_data *rsrc_data = ref_node->rsrc_data;
+	struct io_ring_ctx *ctx = rsrc_data->ctx;
+	struct io_rsrc_put *prsrc, *tmp;
+
+	list_for_each_entry_safe(prsrc, tmp, &ref_node->rsrc_list, list) {
+		list_del(&prsrc->list);
+
+		if (prsrc->tag) {
+			if (ctx->flags & IORING_SETUP_IOPOLL)
+				mutex_lock(&ctx->uring_lock);
+
+			spin_lock(&ctx->completion_lock);
+			io_fill_cqe_aux(ctx, prsrc->tag, 0, 0);
+			io_commit_cqring(ctx);
+			spin_unlock(&ctx->completion_lock);
+			io_cqring_ev_posted(ctx);
+
+			if (ctx->flags & IORING_SETUP_IOPOLL)
+				mutex_unlock(&ctx->uring_lock);
+		}
+
+		rsrc_data->do_put(ctx, prsrc);
+		kfree(prsrc);
+	}
+
+	io_rsrc_node_destroy(ref_node);
+	if (atomic_dec_and_test(&rsrc_data->refs))
+		complete(&rsrc_data->done);
+}
+
+static void io_rsrc_put_work(struct work_struct *work)
+{
+	struct io_ring_ctx *ctx;
+	struct llist_node *node;
+
+	ctx = container_of(work, struct io_ring_ctx, rsrc_put_work.work);
+	node = llist_del_all(&ctx->rsrc_put_llist);
+
+	while (node) {
+		struct io_rsrc_node *ref_node;
+		struct llist_node *next = node->next;
+
+		ref_node = llist_entry(node, struct io_rsrc_node, llist);
+		__io_rsrc_put_work(ref_node);
+		node = next;
+	}
+}
+
+static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
+				 unsigned nr_args, u64 __user *tags)
+{
+	__s32 __user *fds = (__s32 __user *) arg;
+	struct file *file;
+	int fd, ret;
+	unsigned i;
+
+	if (ctx->file_data)
+		return -EBUSY;
+	if (!nr_args)
+		return -EINVAL;
+	if (nr_args > IORING_MAX_FIXED_FILES)
+		return -EMFILE;
+	if (nr_args > rlimit(RLIMIT_NOFILE))
+		return -EMFILE;
+	ret = io_rsrc_node_switch_start(ctx);
+	if (ret)
+		return ret;
+	ret = io_rsrc_data_alloc(ctx, io_rsrc_file_put, tags, nr_args,
+				 &ctx->file_data);
+	if (ret)
+		return ret;
+
+	if (!io_alloc_file_tables(&ctx->file_table, nr_args)) {
+		io_rsrc_data_free(ctx->file_data);
+		ctx->file_data = NULL;
+		return -ENOMEM;
+	}
+
+	for (i = 0; i < nr_args; i++, ctx->nr_user_files++) {
+		struct io_fixed_file *file_slot;
+
+		if (fds && copy_from_user(&fd, &fds[i], sizeof(fd))) {
+			ret = -EFAULT;
+			goto fail;
+		}
+		/* allow sparse sets */
+		if (!fds || fd == -1) {
+			ret = -EINVAL;
+			if (unlikely(*io_get_tag_slot(ctx->file_data, i)))
+				goto fail;
+			continue;
+		}
+
+		file = fget(fd);
+		ret = -EBADF;
+		if (unlikely(!file))
+			goto fail;
+
+		/*
+		 * Don't allow io_uring instances to be registered. If UNIX
+		 * isn't enabled, then this causes a reference cycle and this
+		 * instance can never get freed. If UNIX is enabled we'll
+		 * handle it just fine, but there's still no point in allowing
+		 * a ring fd as it doesn't support regular read/write anyway.
+		 */
+		if (file->f_op == &io_uring_fops) {
+			fput(file);
+			goto fail;
+		}
+		ret = io_scm_file_account(ctx, file);
+		if (ret) {
+			fput(file);
+			goto fail;
+		}
+		file_slot = io_fixed_file_slot(&ctx->file_table, i);
+		io_fixed_file_set(file_slot, file);
+		io_file_bitmap_set(&ctx->file_table, i);
+	}
+
+	io_rsrc_node_switch(ctx, NULL);
+	return 0;
+fail:
+	__io_sqe_files_unregister(ctx);
+	return ret;
+}
+
+static int io_queue_rsrc_removal(struct io_rsrc_data *data, unsigned idx,
+				 struct io_rsrc_node *node, void *rsrc)
+{
+	u64 *tag_slot = io_get_tag_slot(data, idx);
+	struct io_rsrc_put *prsrc;
+
+	prsrc = kzalloc(sizeof(*prsrc), GFP_KERNEL);
+	if (!prsrc)
+		return -ENOMEM;
+
+	prsrc->tag = *tag_slot;
+	*tag_slot = 0;
+	prsrc->rsrc = rsrc;
+	list_add(&prsrc->list, &node->rsrc_list);
+	return 0;
+}
+
+static int io_install_fixed_file(struct io_kiocb *req, struct file *file,
+				 unsigned int issue_flags, u32 slot_index)
+	__must_hold(&req->ctx->uring_lock)
+{
+	struct io_ring_ctx *ctx = req->ctx;
+	bool needs_switch = false;
+	struct io_fixed_file *file_slot;
+	int ret;
+
+	if (file->f_op == &io_uring_fops)
+		return -EBADF;
+	if (!ctx->file_data)
+		return -ENXIO;
+	if (slot_index >= ctx->nr_user_files)
+		return -EINVAL;
+
+	slot_index = array_index_nospec(slot_index, ctx->nr_user_files);
+	file_slot = io_fixed_file_slot(&ctx->file_table, slot_index);
+
+	if (file_slot->file_ptr) {
+		struct file *old_file;
+
+		ret = io_rsrc_node_switch_start(ctx);
+		if (ret)
+			goto err;
+
+		old_file = (struct file *)(file_slot->file_ptr & FFS_MASK);
+		ret = io_queue_rsrc_removal(ctx->file_data, slot_index,
+					    ctx->rsrc_node, old_file);
+		if (ret)
+			goto err;
+		file_slot->file_ptr = 0;
+		io_file_bitmap_clear(&ctx->file_table, slot_index);
+		needs_switch = true;
+	}
+
+	ret = io_scm_file_account(ctx, file);
+	if (!ret) {
+		*io_get_tag_slot(ctx->file_data, slot_index) = 0;
+		io_fixed_file_set(file_slot, file);
+		io_file_bitmap_set(&ctx->file_table, slot_index);
+	}
+err:
+	if (needs_switch)
+		io_rsrc_node_switch(ctx, ctx->file_data);
+	if (ret)
+		fput(file);
+	return ret;
+}
+
+static int __io_close_fixed(struct io_kiocb *req, unsigned int issue_flags,
+			    unsigned int offset)
+{
+	struct io_ring_ctx *ctx = req->ctx;
+	struct io_fixed_file *file_slot;
+	struct file *file;
+	int ret;
+
+	io_ring_submit_lock(ctx, issue_flags);
+	ret = -ENXIO;
+	if (unlikely(!ctx->file_data))
+		goto out;
+	ret = -EINVAL;
+	if (offset >= ctx->nr_user_files)
+		goto out;
+	ret = io_rsrc_node_switch_start(ctx);
+	if (ret)
+		goto out;
+
+	offset = array_index_nospec(offset, ctx->nr_user_files);
+	file_slot = io_fixed_file_slot(&ctx->file_table, offset);
+	ret = -EBADF;
+	if (!file_slot->file_ptr)
+		goto out;
+
+	file = (struct file *)(file_slot->file_ptr & FFS_MASK);
+	ret = io_queue_rsrc_removal(ctx->file_data, offset, ctx->rsrc_node, file);
+	if (ret)
+		goto out;
+
+	file_slot->file_ptr = 0;
+	io_file_bitmap_clear(&ctx->file_table, offset);
+	io_rsrc_node_switch(ctx, ctx->file_data);
+	ret = 0;
+out:
+	io_ring_submit_unlock(ctx, issue_flags);
+	return ret;
+}
+
+static inline int io_close_fixed(struct io_kiocb *req, unsigned int issue_flags)
+{
+	return __io_close_fixed(req, issue_flags, req->close.file_slot - 1);
+}
+
+static int __io_sqe_files_update(struct io_ring_ctx *ctx,
+				 struct io_uring_rsrc_update2 *up,
+				 unsigned nr_args)
+{
+	u64 __user *tags = u64_to_user_ptr(up->tags);
+	__s32 __user *fds = u64_to_user_ptr(up->data);
+	struct io_rsrc_data *data = ctx->file_data;
+	struct io_fixed_file *file_slot;
+	struct file *file;
+	int fd, i, err = 0;
+	unsigned int done;
+	bool needs_switch = false;
+
+	if (!ctx->file_data)
+		return -ENXIO;
+	if (up->offset + nr_args > ctx->nr_user_files)
+		return -EINVAL;
+
+	for (done = 0; done < nr_args; done++) {
+		u64 tag = 0;
+
+		if ((tags && copy_from_user(&tag, &tags[done], sizeof(tag))) ||
+		    copy_from_user(&fd, &fds[done], sizeof(fd))) {
+			err = -EFAULT;
+			break;
+		}
+		if ((fd == IORING_REGISTER_FILES_SKIP || fd == -1) && tag) {
+			err = -EINVAL;
+			break;
+		}
+		if (fd == IORING_REGISTER_FILES_SKIP)
+			continue;
+
+		i = array_index_nospec(up->offset + done, ctx->nr_user_files);
+		file_slot = io_fixed_file_slot(&ctx->file_table, i);
+
+		if (file_slot->file_ptr) {
+			file = (struct file *)(file_slot->file_ptr & FFS_MASK);
+			err = io_queue_rsrc_removal(data, i, ctx->rsrc_node, file);
+			if (err)
+				break;
+			file_slot->file_ptr = 0;
+			io_file_bitmap_clear(&ctx->file_table, i);
+			needs_switch = true;
+		}
+		if (fd != -1) {
+			file = fget(fd);
+			if (!file) {
+				err = -EBADF;
+				break;
+			}
+			/*
+			 * Don't allow io_uring instances to be registered. If
+			 * UNIX isn't enabled, then this causes a reference
+			 * cycle and this instance can never get freed. If UNIX
+			 * is enabled we'll handle it just fine, but there's
+			 * still no point in allowing a ring fd as it doesn't
+			 * support regular read/write anyway.
+			 */
+			if (file->f_op == &io_uring_fops) {
+				fput(file);
+				err = -EBADF;
+				break;
+			}
+			err = io_scm_file_account(ctx, file);
+			if (err) {
+				fput(file);
+				break;
+			}
+			*io_get_tag_slot(data, i) = tag;
+			io_fixed_file_set(file_slot, file);
+			io_file_bitmap_set(&ctx->file_table, i);
+		}
+	}
+
+	if (needs_switch)
+		io_rsrc_node_switch(ctx, data);
+	return done ? done : err;
+}
+
+static struct io_wq *io_init_wq_offload(struct io_ring_ctx *ctx,
+					struct task_struct *task)
+{
+	struct io_wq_hash *hash;
+	struct io_wq_data data;
+	unsigned int concurrency;
+
+	mutex_lock(&ctx->uring_lock);
+	hash = ctx->hash_map;
+	if (!hash) {
+		hash = kzalloc(sizeof(*hash), GFP_KERNEL);
+		if (!hash) {
+			mutex_unlock(&ctx->uring_lock);
+			return ERR_PTR(-ENOMEM);
+		}
+		refcount_set(&hash->refs, 1);
+		init_waitqueue_head(&hash->wait);
+		ctx->hash_map = hash;
+	}
+	mutex_unlock(&ctx->uring_lock);
+
+	data.hash = hash;
+	data.task = task;
+	data.free_work = io_wq_free_work;
+	data.do_work = io_wq_submit_work;
+
+	/* Do QD, or 4 * CPUS, whatever is smallest */
+	concurrency = min(ctx->sq_entries, 4 * num_online_cpus());
+
+	return io_wq_create(concurrency, &data);
+}
+
+static __cold int io_uring_alloc_task_context(struct task_struct *task,
+					      struct io_ring_ctx *ctx)
+{
+	struct io_uring_task *tctx;
+	int ret;
+
+	tctx = kzalloc(sizeof(*tctx), GFP_KERNEL);
+	if (unlikely(!tctx))
+		return -ENOMEM;
+
+	tctx->registered_rings = kcalloc(IO_RINGFD_REG_MAX,
+					 sizeof(struct file *), GFP_KERNEL);
+	if (unlikely(!tctx->registered_rings)) {
+		kfree(tctx);
+		return -ENOMEM;
+	}
+
+	ret = percpu_counter_init(&tctx->inflight, 0, GFP_KERNEL);
+	if (unlikely(ret)) {
+		kfree(tctx->registered_rings);
+		kfree(tctx);
+		return ret;
+	}
+
+	tctx->io_wq = io_init_wq_offload(ctx, task);
+	if (IS_ERR(tctx->io_wq)) {
+		ret = PTR_ERR(tctx->io_wq);
+		percpu_counter_destroy(&tctx->inflight);
+		kfree(tctx->registered_rings);
+		kfree(tctx);
+		return ret;
+	}
+
+	xa_init(&tctx->xa);
+	init_waitqueue_head(&tctx->wait);
+	atomic_set(&tctx->in_idle, 0);
+	atomic_set(&tctx->inflight_tracked, 0);
+	task->io_uring = tctx;
+	spin_lock_init(&tctx->task_lock);
+	INIT_WQ_LIST(&tctx->task_list);
+	INIT_WQ_LIST(&tctx->prio_task_list);
+	init_task_work(&tctx->task_work, tctx_task_work);
+	return 0;
+}
+
+void __io_uring_free(struct task_struct *tsk)
+{
+	struct io_uring_task *tctx = tsk->io_uring;
+
+	WARN_ON_ONCE(!xa_empty(&tctx->xa));
+	WARN_ON_ONCE(tctx->io_wq);
+	WARN_ON_ONCE(tctx->cached_refs);
+
+	kfree(tctx->registered_rings);
+	percpu_counter_destroy(&tctx->inflight);
+	kfree(tctx);
+	tsk->io_uring = NULL;
+}
+
+static __cold int io_sq_offload_create(struct io_ring_ctx *ctx,
+				       struct io_uring_params *p)
+{
+	int ret;
+
+	/* Retain compatibility with failing for an invalid attach attempt */
+	if ((ctx->flags & (IORING_SETUP_ATTACH_WQ | IORING_SETUP_SQPOLL)) ==
+				IORING_SETUP_ATTACH_WQ) {
+		struct fd f;
+
+		f = fdget(p->wq_fd);
+		if (!f.file)
+			return -ENXIO;
+		if (f.file->f_op != &io_uring_fops) {
+			fdput(f);
+			return -EINVAL;
+		}
+		fdput(f);
+	}
+	if (ctx->flags & IORING_SETUP_SQPOLL) {
+		struct task_struct *tsk;
+		struct io_sq_data *sqd;
+		bool attached;
+
+		ret = security_uring_sqpoll();
+		if (ret)
+			return ret;
+
+		sqd = io_get_sq_data(p, &attached);
+		if (IS_ERR(sqd)) {
+			ret = PTR_ERR(sqd);
+			goto err;
+		}
+
+		ctx->sq_creds = get_current_cred();
+		ctx->sq_data = sqd;
+		ctx->sq_thread_idle = msecs_to_jiffies(p->sq_thread_idle);
+		if (!ctx->sq_thread_idle)
+			ctx->sq_thread_idle = HZ;
+
+		io_sq_thread_park(sqd);
+		list_add(&ctx->sqd_list, &sqd->ctx_list);
+		io_sqd_update_thread_idle(sqd);
+		/* don't attach to a dying SQPOLL thread, would be racy */
+		ret = (attached && !sqd->thread) ? -ENXIO : 0;
+		io_sq_thread_unpark(sqd);
+
+		if (ret < 0)
+			goto err;
+		if (attached)
+			return 0;
+
+		if (p->flags & IORING_SETUP_SQ_AFF) {
+			int cpu = p->sq_thread_cpu;
+
+			ret = -EINVAL;
+			if (cpu >= nr_cpu_ids || !cpu_online(cpu))
+				goto err_sqpoll;
+			sqd->sq_cpu = cpu;
+		} else {
+			sqd->sq_cpu = -1;
+		}
+
+		sqd->task_pid = current->pid;
+		sqd->task_tgid = current->tgid;
+		tsk = create_io_thread(io_sq_thread, sqd, NUMA_NO_NODE);
+		if (IS_ERR(tsk)) {
+			ret = PTR_ERR(tsk);
+			goto err_sqpoll;
+		}
+
+		sqd->thread = tsk;
+		ret = io_uring_alloc_task_context(tsk, ctx);
+		wake_up_new_task(tsk);
+		if (ret)
+			goto err;
+	} else if (p->flags & IORING_SETUP_SQ_AFF) {
+		/* Can't have SQ_AFF without SQPOLL */
+		ret = -EINVAL;
+		goto err;
+	}
+
+	return 0;
+err_sqpoll:
+	complete(&ctx->sq_data->exited);
+err:
+	io_sq_thread_finish(ctx);
+	return ret;
+}
+
+static inline void __io_unaccount_mem(struct user_struct *user,
+				      unsigned long nr_pages)
+{
+	atomic_long_sub(nr_pages, &user->locked_vm);
+}
+
+static inline int __io_account_mem(struct user_struct *user,
+				   unsigned long nr_pages)
+{
+	unsigned long page_limit, cur_pages, new_pages;
+
+	/* Don't allow more pages than we can safely lock */
+	page_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
+
+	do {
+		cur_pages = atomic_long_read(&user->locked_vm);
+		new_pages = cur_pages + nr_pages;
+		if (new_pages > page_limit)
+			return -ENOMEM;
+	} while (atomic_long_cmpxchg(&user->locked_vm, cur_pages,
+					new_pages) != cur_pages);
+
+	return 0;
+}
+
+static void io_unaccount_mem(struct io_ring_ctx *ctx, unsigned long nr_pages)
+{
+	if (ctx->user)
+		__io_unaccount_mem(ctx->user, nr_pages);
+
+	if (ctx->mm_account)
+		atomic64_sub(nr_pages, &ctx->mm_account->pinned_vm);
+}
+
+static int io_account_mem(struct io_ring_ctx *ctx, unsigned long nr_pages)
+{
+	int ret;
+
+	if (ctx->user) {
+		ret = __io_account_mem(ctx->user, nr_pages);
+		if (ret)
+			return ret;
+	}
+
+	if (ctx->mm_account)
+		atomic64_add(nr_pages, &ctx->mm_account->pinned_vm);
+
+	return 0;
+}
+
+static void io_mem_free(void *ptr)
+{
+	struct page *page;
+
+	if (!ptr)
+		return;
+
+	page = virt_to_head_page(ptr);
+	if (put_page_testzero(page))
+		free_compound_page(page);
+}
+
+static void *io_mem_alloc(size_t size)
+{
+	gfp_t gfp = GFP_KERNEL_ACCOUNT | __GFP_ZERO | __GFP_NOWARN | __GFP_COMP;
+
+	return (void *) __get_free_pages(gfp, get_order(size));
+}
+
+static unsigned long rings_size(struct io_ring_ctx *ctx, unsigned int sq_entries,
+				unsigned int cq_entries, size_t *sq_offset)
+{
+	struct io_rings *rings;
+	size_t off, sq_array_size;
+
+	off = struct_size(rings, cqes, cq_entries);
+	if (off == SIZE_MAX)
+		return SIZE_MAX;
+	if (ctx->flags & IORING_SETUP_CQE32) {
+		if (check_shl_overflow(off, 1, &off))
+			return SIZE_MAX;
+	}
+
+#ifdef CONFIG_SMP
+	off = ALIGN(off, SMP_CACHE_BYTES);
+	if (off == 0)
+		return SIZE_MAX;
+#endif
+
+	if (sq_offset)
+		*sq_offset = off;
+
+	sq_array_size = array_size(sizeof(u32), sq_entries);
+	if (sq_array_size == SIZE_MAX)
+		return SIZE_MAX;
+
+	if (check_add_overflow(off, sq_array_size, &off))
+		return SIZE_MAX;
+
+	return off;
+}
+
+static void io_buffer_unmap(struct io_ring_ctx *ctx, struct io_mapped_ubuf **slot)
+{
+	struct io_mapped_ubuf *imu = *slot;
+	unsigned int i;
+
+	if (imu != ctx->dummy_ubuf) {
+		for (i = 0; i < imu->nr_bvecs; i++)
+			unpin_user_page(imu->bvec[i].bv_page);
+		if (imu->acct_pages)
+			io_unaccount_mem(ctx, imu->acct_pages);
+		kvfree(imu);
+	}
+	*slot = NULL;
+}
+
+static void io_rsrc_buf_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc)
+{
+	io_buffer_unmap(ctx, &prsrc->buf);
+	prsrc->buf = NULL;
+}
+
+static void __io_sqe_buffers_unregister(struct io_ring_ctx *ctx)
+{
+	unsigned int i;
+
+	for (i = 0; i < ctx->nr_user_bufs; i++)
+		io_buffer_unmap(ctx, &ctx->user_bufs[i]);
+	kfree(ctx->user_bufs);
+	io_rsrc_data_free(ctx->buf_data);
+	ctx->user_bufs = NULL;
+	ctx->buf_data = NULL;
+	ctx->nr_user_bufs = 0;
+}
+
+static int io_sqe_buffers_unregister(struct io_ring_ctx *ctx)
+{
+	unsigned nr = ctx->nr_user_bufs;
+	int ret;
+
+	if (!ctx->buf_data)
+		return -ENXIO;
+
+	/*
+	 * Quiesce may unlock ->uring_lock, and while it's not held
+	 * prevent new requests using the table.
+	 */
+	ctx->nr_user_bufs = 0;
+	ret = io_rsrc_ref_quiesce(ctx->buf_data, ctx);
+	ctx->nr_user_bufs = nr;
+	if (!ret)
+		__io_sqe_buffers_unregister(ctx);
+	return ret;
+}
+
+static int io_copy_iov(struct io_ring_ctx *ctx, struct iovec *dst,
+		       void __user *arg, unsigned index)
+{
+	struct iovec __user *src;
+
+#ifdef CONFIG_COMPAT
+	if (ctx->compat) {
+		struct compat_iovec __user *ciovs;
+		struct compat_iovec ciov;
+
+		ciovs = (struct compat_iovec __user *) arg;
+		if (copy_from_user(&ciov, &ciovs[index], sizeof(ciov)))
+			return -EFAULT;
+
+		dst->iov_base = u64_to_user_ptr((u64)ciov.iov_base);
+		dst->iov_len = ciov.iov_len;
+		return 0;
+	}
+#endif
+	src = (struct iovec __user *) arg;
+	if (copy_from_user(dst, &src[index], sizeof(*dst)))
+		return -EFAULT;
+	return 0;
+}
+
+/*
+ * Not super efficient, but this is just a registration time. And we do cache
+ * the last compound head, so generally we'll only do a full search if we don't
+ * match that one.
+ *
+ * We check if the given compound head page has already been accounted, to
+ * avoid double accounting it. This allows us to account the full size of the
+ * page, not just the constituent pages of a huge page.
+ */
+static bool headpage_already_acct(struct io_ring_ctx *ctx, struct page **pages,
+				  int nr_pages, struct page *hpage)
+{
+	int i, j;
+
+	/* check current page array */
+	for (i = 0; i < nr_pages; i++) {
+		if (!PageCompound(pages[i]))
+			continue;
+		if (compound_head(pages[i]) == hpage)
+			return true;
+	}
+
+	/* check previously registered pages */
+	for (i = 0; i < ctx->nr_user_bufs; i++) {
+		struct io_mapped_ubuf *imu = ctx->user_bufs[i];
+
+		for (j = 0; j < imu->nr_bvecs; j++) {
+			if (!PageCompound(imu->bvec[j].bv_page))
+				continue;
+			if (compound_head(imu->bvec[j].bv_page) == hpage)
+				return true;
+		}
+	}
+
+	return false;
+}
+
+static int io_buffer_account_pin(struct io_ring_ctx *ctx, struct page **pages,
+				 int nr_pages, struct io_mapped_ubuf *imu,
+				 struct page **last_hpage)
+{
+	int i, ret;
+
+	imu->acct_pages = 0;
+	for (i = 0; i < nr_pages; i++) {
+		if (!PageCompound(pages[i])) {
+			imu->acct_pages++;
+		} else {
+			struct page *hpage;
+
+			hpage = compound_head(pages[i]);
+			if (hpage == *last_hpage)
+				continue;
+			*last_hpage = hpage;
+			if (headpage_already_acct(ctx, pages, i, hpage))
+				continue;
+			imu->acct_pages += page_size(hpage) >> PAGE_SHIFT;
+		}
+	}
+
+	if (!imu->acct_pages)
+		return 0;
+
+	ret = io_account_mem(ctx, imu->acct_pages);
+	if (ret)
+		imu->acct_pages = 0;
+	return ret;
+}
+
+static struct page **io_pin_pages(unsigned long ubuf, unsigned long len,
+				  int *npages)
+{
+	unsigned long start, end, nr_pages;
+	struct vm_area_struct **vmas = NULL;
+	struct page **pages = NULL;
+	int i, pret, ret = -ENOMEM;
+
+	end = (ubuf + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
+	start = ubuf >> PAGE_SHIFT;
+	nr_pages = end - start;
+
+	pages = kvmalloc_array(nr_pages, sizeof(struct page *), GFP_KERNEL);
+	if (!pages)
+		goto done;
+
+	vmas = kvmalloc_array(nr_pages, sizeof(struct vm_area_struct *),
+			      GFP_KERNEL);
+	if (!vmas)
+		goto done;
+
+	ret = 0;
+	mmap_read_lock(current->mm);
+	pret = pin_user_pages(ubuf, nr_pages, FOLL_WRITE | FOLL_LONGTERM,
+			      pages, vmas);
+	if (pret == nr_pages) {
+		/* don't support file backed memory */
+		for (i = 0; i < nr_pages; i++) {
+			struct vm_area_struct *vma = vmas[i];
+
+			if (vma_is_shmem(vma))
+				continue;
+			if (vma->vm_file &&
+			    !is_file_hugepages(vma->vm_file)) {
+				ret = -EOPNOTSUPP;
+				break;
+			}
+		}
+		*npages = nr_pages;
+	} else {
+		ret = pret < 0 ? pret : -EFAULT;
+	}
+	mmap_read_unlock(current->mm);
+	if (ret) {
+		/*
+		 * if we did partial map, or found file backed vmas,
+		 * release any pages we did get
+		 */
+		if (pret > 0)
+			unpin_user_pages(pages, pret);
+		goto done;
+	}
+	ret = 0;
+done:
+	kvfree(vmas);
+	if (ret < 0) {
+		kvfree(pages);
+		pages = ERR_PTR(ret);
+	}
+	return pages;
+}
+
+static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov,
+				  struct io_mapped_ubuf **pimu,
+				  struct page **last_hpage)
+{
+	struct io_mapped_ubuf *imu = NULL;
+	struct page **pages = NULL;
+	unsigned long off;
+	size_t size;
+	int ret, nr_pages, i;
+
+	if (!iov->iov_base) {
+		*pimu = ctx->dummy_ubuf;
+		return 0;
+	}
+
+	*pimu = NULL;
+	ret = -ENOMEM;
+
+	pages = io_pin_pages((unsigned long) iov->iov_base, iov->iov_len,
+				&nr_pages);
+	if (IS_ERR(pages)) {
+		ret = PTR_ERR(pages);
+		pages = NULL;
+		goto done;
+	}
+
+	imu = kvmalloc(struct_size(imu, bvec, nr_pages), GFP_KERNEL);
+	if (!imu)
+		goto done;
+
+	ret = io_buffer_account_pin(ctx, pages, nr_pages, imu, last_hpage);
+	if (ret) {
+		unpin_user_pages(pages, nr_pages);
+		goto done;
+	}
+
+	off = (unsigned long) iov->iov_base & ~PAGE_MASK;
+	size = iov->iov_len;
+	for (i = 0; i < nr_pages; i++) {
+		size_t vec_len;
+
+		vec_len = min_t(size_t, size, PAGE_SIZE - off);
+		imu->bvec[i].bv_page = pages[i];
+		imu->bvec[i].bv_len = vec_len;
+		imu->bvec[i].bv_offset = off;
+		off = 0;
+		size -= vec_len;
+	}
+	/* store original address for later verification */
+	imu->ubuf = (unsigned long) iov->iov_base;
+	imu->ubuf_end = imu->ubuf + iov->iov_len;
+	imu->nr_bvecs = nr_pages;
+	*pimu = imu;
+	ret = 0;
+done:
+	if (ret)
+		kvfree(imu);
+	kvfree(pages);
+	return ret;
+}
+
+static int io_buffers_map_alloc(struct io_ring_ctx *ctx, unsigned int nr_args)
+{
+	ctx->user_bufs = kcalloc(nr_args, sizeof(*ctx->user_bufs), GFP_KERNEL);
+	return ctx->user_bufs ? 0 : -ENOMEM;
+}
+
+static int io_buffer_validate(struct iovec *iov)
+{
+	unsigned long tmp, acct_len = iov->iov_len + (PAGE_SIZE - 1);
+
+	/*
+	 * Don't impose further limits on the size and buffer
+	 * constraints here, we'll -EINVAL later when IO is
+	 * submitted if they are wrong.
+	 */
+	if (!iov->iov_base)
+		return iov->iov_len ? -EFAULT : 0;
+	if (!iov->iov_len)
+		return -EFAULT;
+
+	/* arbitrary limit, but we need something */
+	if (iov->iov_len > SZ_1G)
+		return -EFAULT;
+
+	if (check_add_overflow((unsigned long)iov->iov_base, acct_len, &tmp))
+		return -EOVERFLOW;
+
+	return 0;
+}
+
+static int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
+				   unsigned int nr_args, u64 __user *tags)
+{
+	struct page *last_hpage = NULL;
+	struct io_rsrc_data *data;
+	int i, ret;
+	struct iovec iov;
+
+	if (ctx->user_bufs)
+		return -EBUSY;
+	if (!nr_args || nr_args > IORING_MAX_REG_BUFFERS)
+		return -EINVAL;
+	ret = io_rsrc_node_switch_start(ctx);
+	if (ret)
+		return ret;
+	ret = io_rsrc_data_alloc(ctx, io_rsrc_buf_put, tags, nr_args, &data);
+	if (ret)
+		return ret;
+	ret = io_buffers_map_alloc(ctx, nr_args);
+	if (ret) {
+		io_rsrc_data_free(data);
+		return ret;
+	}
+
+	for (i = 0; i < nr_args; i++, ctx->nr_user_bufs++) {
+		if (arg) {
+			ret = io_copy_iov(ctx, &iov, arg, i);
+			if (ret)
+				break;
+			ret = io_buffer_validate(&iov);
+			if (ret)
+				break;
+		} else {
+			memset(&iov, 0, sizeof(iov));
+		}
+
+		if (!iov.iov_base && *io_get_tag_slot(data, i)) {
+			ret = -EINVAL;
+			break;
+		}
+
+		ret = io_sqe_buffer_register(ctx, &iov, &ctx->user_bufs[i],
+					     &last_hpage);
+		if (ret)
+			break;
+	}
+
+	WARN_ON_ONCE(ctx->buf_data);
+
+	ctx->buf_data = data;
+	if (ret)
+		__io_sqe_buffers_unregister(ctx);
+	else
+		io_rsrc_node_switch(ctx, NULL);
+	return ret;
+}
+
+static int __io_sqe_buffers_update(struct io_ring_ctx *ctx,
+				   struct io_uring_rsrc_update2 *up,
+				   unsigned int nr_args)
+{
+	u64 __user *tags = u64_to_user_ptr(up->tags);
+	struct iovec iov, __user *iovs = u64_to_user_ptr(up->data);
+	struct page *last_hpage = NULL;
+	bool needs_switch = false;
+	__u32 done;
+	int i, err;
+
+	if (!ctx->buf_data)
+		return -ENXIO;
+	if (up->offset + nr_args > ctx->nr_user_bufs)
+		return -EINVAL;
+
+	for (done = 0; done < nr_args; done++) {
+		struct io_mapped_ubuf *imu;
+		int offset = up->offset + done;
+		u64 tag = 0;
+
+		err = io_copy_iov(ctx, &iov, iovs, done);
+		if (err)
+			break;
+		if (tags && copy_from_user(&tag, &tags[done], sizeof(tag))) {
+			err = -EFAULT;
+			break;
+		}
+		err = io_buffer_validate(&iov);
+		if (err)
+			break;
+		if (!iov.iov_base && tag) {
+			err = -EINVAL;
+			break;
+		}
+		err = io_sqe_buffer_register(ctx, &iov, &imu, &last_hpage);
+		if (err)
+			break;
+
+		i = array_index_nospec(offset, ctx->nr_user_bufs);
+		if (ctx->user_bufs[i] != ctx->dummy_ubuf) {
+			err = io_queue_rsrc_removal(ctx->buf_data, i,
+						    ctx->rsrc_node, ctx->user_bufs[i]);
+			if (unlikely(err)) {
+				io_buffer_unmap(ctx, &imu);
+				break;
+			}
+			ctx->user_bufs[i] = NULL;
+			needs_switch = true;
+		}
+
+		ctx->user_bufs[i] = imu;
+		*io_get_tag_slot(ctx->buf_data, offset) = tag;
+	}
+
+	if (needs_switch)
+		io_rsrc_node_switch(ctx, ctx->buf_data);
+	return done ? done : err;
+}
+
+static int io_eventfd_register(struct io_ring_ctx *ctx, void __user *arg,
+			       unsigned int eventfd_async)
+{
+	struct io_ev_fd *ev_fd;
+	__s32 __user *fds = arg;
+	int fd;
+
+	ev_fd = rcu_dereference_protected(ctx->io_ev_fd,
+					lockdep_is_held(&ctx->uring_lock));
+	if (ev_fd)
+		return -EBUSY;
+
+	if (copy_from_user(&fd, fds, sizeof(*fds)))
+		return -EFAULT;
+
+	ev_fd = kmalloc(sizeof(*ev_fd), GFP_KERNEL);
+	if (!ev_fd)
+		return -ENOMEM;
+
+	ev_fd->cq_ev_fd = eventfd_ctx_fdget(fd);
+	if (IS_ERR(ev_fd->cq_ev_fd)) {
+		int ret = PTR_ERR(ev_fd->cq_ev_fd);
+		kfree(ev_fd);
+		return ret;
+	}
+	ev_fd->eventfd_async = eventfd_async;
+	ctx->has_evfd = true;
+	rcu_assign_pointer(ctx->io_ev_fd, ev_fd);
+	return 0;
+}
+
+static void io_eventfd_put(struct rcu_head *rcu)
+{
+	struct io_ev_fd *ev_fd = container_of(rcu, struct io_ev_fd, rcu);
+
+	eventfd_ctx_put(ev_fd->cq_ev_fd);
+	kfree(ev_fd);
+}
+
+static int io_eventfd_unregister(struct io_ring_ctx *ctx)
+{
+	struct io_ev_fd *ev_fd;
+
+	ev_fd = rcu_dereference_protected(ctx->io_ev_fd,
+					lockdep_is_held(&ctx->uring_lock));
+	if (ev_fd) {
+		ctx->has_evfd = false;
+		rcu_assign_pointer(ctx->io_ev_fd, NULL);
+		call_rcu(&ev_fd->rcu, io_eventfd_put);
+		return 0;
+	}
+
+	return -ENXIO;
+}
+
+static void io_destroy_buffers(struct io_ring_ctx *ctx)
+{
+	struct io_buffer_list *bl;
+	unsigned long index;
+	int i;
+
+	for (i = 0; i < BGID_ARRAY; i++) {
+		if (!ctx->io_bl)
+			break;
+		__io_remove_buffers(ctx, &ctx->io_bl[i], -1U);
+	}
+
+	xa_for_each(&ctx->io_bl_xa, index, bl) {
+		xa_erase(&ctx->io_bl_xa, bl->bgid);
+		__io_remove_buffers(ctx, bl, -1U);
+		kfree(bl);
+	}
+
+	while (!list_empty(&ctx->io_buffers_pages)) {
+		struct page *page;
+
+		page = list_first_entry(&ctx->io_buffers_pages, struct page, lru);
+		list_del_init(&page->lru);
+		__free_page(page);
+	}
+}
+
+static void io_req_caches_free(struct io_ring_ctx *ctx)
+{
+	struct io_submit_state *state = &ctx->submit_state;
+	int nr = 0;
+
+	mutex_lock(&ctx->uring_lock);
+	io_flush_cached_locked_reqs(ctx, state);
+
+	while (!io_req_cache_empty(ctx)) {
+		struct io_wq_work_node *node;
+		struct io_kiocb *req;
+
+		node = wq_stack_extract(&state->free_list);
+		req = container_of(node, struct io_kiocb, comp_list);
+		kmem_cache_free(req_cachep, req);
+		nr++;
+	}
+	if (nr)
+		percpu_ref_put_many(&ctx->refs, nr);
+	mutex_unlock(&ctx->uring_lock);
+}
+
+static void io_wait_rsrc_data(struct io_rsrc_data *data)
+{
+	if (data && !atomic_dec_and_test(&data->refs))
+		wait_for_completion(&data->done);
+}
+
+static void io_flush_apoll_cache(struct io_ring_ctx *ctx)
+{
+	struct async_poll *apoll;
+
+	while (!list_empty(&ctx->apoll_cache)) {
+		apoll = list_first_entry(&ctx->apoll_cache, struct async_poll,
+						poll.wait.entry);
+		list_del(&apoll->poll.wait.entry);
+		kfree(apoll);
+	}
+}
+
+static __cold void io_ring_ctx_free(struct io_ring_ctx *ctx)
+{
+	io_sq_thread_finish(ctx);
+
+	if (ctx->mm_account) {
+		mmdrop(ctx->mm_account);
+		ctx->mm_account = NULL;
+	}
+
+	io_rsrc_refs_drop(ctx);
+	/* __io_rsrc_put_work() may need uring_lock to progress, wait w/o it */
+	io_wait_rsrc_data(ctx->buf_data);
+	io_wait_rsrc_data(ctx->file_data);
+
+	mutex_lock(&ctx->uring_lock);
+	if (ctx->buf_data)
+		__io_sqe_buffers_unregister(ctx);
+	if (ctx->file_data)
+		__io_sqe_files_unregister(ctx);
+	if (ctx->rings)
+		__io_cqring_overflow_flush(ctx, true);
+	io_eventfd_unregister(ctx);
+	io_flush_apoll_cache(ctx);
+	mutex_unlock(&ctx->uring_lock);
+	io_destroy_buffers(ctx);
+	if (ctx->sq_creds)
+		put_cred(ctx->sq_creds);
+
+	/* there are no registered resources left, nobody uses it */
+	if (ctx->rsrc_node)
+		io_rsrc_node_destroy(ctx->rsrc_node);
+	if (ctx->rsrc_backup_node)
+		io_rsrc_node_destroy(ctx->rsrc_backup_node);
+	flush_delayed_work(&ctx->rsrc_put_work);
+	flush_delayed_work(&ctx->fallback_work);
+
+	WARN_ON_ONCE(!list_empty(&ctx->rsrc_ref_list));
+	WARN_ON_ONCE(!llist_empty(&ctx->rsrc_put_llist));
+
+#if defined(CONFIG_UNIX)
+	if (ctx->ring_sock) {
+		ctx->ring_sock->file = NULL; /* so that iput() is called */
+		sock_release(ctx->ring_sock);
+	}
+#endif
+	WARN_ON_ONCE(!list_empty(&ctx->ltimeout_list));
+
+	io_mem_free(ctx->rings);
+	io_mem_free(ctx->sq_sqes);
+
+	percpu_ref_exit(&ctx->refs);
+	free_uid(ctx->user);
+	io_req_caches_free(ctx);
+	if (ctx->hash_map)
+		io_wq_put_hash(ctx->hash_map);
+	kfree(ctx->cancel_hash);
+	kfree(ctx->dummy_ubuf);
+	kfree(ctx->io_bl);
+	xa_destroy(&ctx->io_bl_xa);
+	kfree(ctx);
+}
+
+static __poll_t io_uring_poll(struct file *file, poll_table *wait)
+{
+	struct io_ring_ctx *ctx = file->private_data;
+	__poll_t mask = 0;
+
+	poll_wait(file, &ctx->cq_wait, wait);
+	/*
+	 * synchronizes with barrier from wq_has_sleeper call in
+	 * io_commit_cqring
+	 */
+	smp_rmb();
+	if (!io_sqring_full(ctx))
+		mask |= EPOLLOUT | EPOLLWRNORM;
+
+	/*
+	 * Don't flush cqring overflow list here, just do a simple check.
+	 * Otherwise there could possible be ABBA deadlock:
+	 *      CPU0                    CPU1
+	 *      ----                    ----
+	 * lock(&ctx->uring_lock);
+	 *                              lock(&ep->mtx);
+	 *                              lock(&ctx->uring_lock);
+	 * lock(&ep->mtx);
+	 *
+	 * Users may get EPOLLIN meanwhile seeing nothing in cqring, this
+	 * pushs them to do the flush.
+	 */
+	if (io_cqring_events(ctx) ||
+	    test_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq))
+		mask |= EPOLLIN | EPOLLRDNORM;
+
+	return mask;
+}
+
+static int io_unregister_personality(struct io_ring_ctx *ctx, unsigned id)
+{
+	const struct cred *creds;
+
+	creds = xa_erase(&ctx->personalities, id);
+	if (creds) {
+		put_cred(creds);
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
+struct io_tctx_exit {
+	struct callback_head		task_work;
+	struct completion		completion;
+	struct io_ring_ctx		*ctx;
+};
+
+static __cold void io_tctx_exit_cb(struct callback_head *cb)
+{
+	struct io_uring_task *tctx = current->io_uring;
+	struct io_tctx_exit *work;
+
+	work = container_of(cb, struct io_tctx_exit, task_work);
+	/*
+	 * When @in_idle, we're in cancellation and it's racy to remove the
+	 * node. It'll be removed by the end of cancellation, just ignore it.
+	 */
+	if (!atomic_read(&tctx->in_idle))
+		io_uring_del_tctx_node((unsigned long)work->ctx);
+	complete(&work->completion);
+}
+
+static __cold bool io_cancel_ctx_cb(struct io_wq_work *work, void *data)
+{
+	struct io_kiocb *req = container_of(work, struct io_kiocb, work);
+
+	return req->ctx == data;
+}
+
+static __cold void io_ring_exit_work(struct work_struct *work)
+{
+	struct io_ring_ctx *ctx = container_of(work, struct io_ring_ctx, exit_work);
+	unsigned long timeout = jiffies + HZ * 60 * 5;
+	unsigned long interval = HZ / 20;
+	struct io_tctx_exit exit;
+	struct io_tctx_node *node;
+	int ret;
+
+	/*
+	 * If we're doing polled IO and end up having requests being
+	 * submitted async (out-of-line), then completions can come in while
+	 * we're waiting for refs to drop. We need to reap these manually,
+	 * as nobody else will be looking for them.
+	 */
+	do {
+		io_uring_try_cancel_requests(ctx, NULL, true);
+		if (ctx->sq_data) {
+			struct io_sq_data *sqd = ctx->sq_data;
+			struct task_struct *tsk;
+
+			io_sq_thread_park(sqd);
+			tsk = sqd->thread;
+			if (tsk && tsk->io_uring && tsk->io_uring->io_wq)
+				io_wq_cancel_cb(tsk->io_uring->io_wq,
+						io_cancel_ctx_cb, ctx, true);
+			io_sq_thread_unpark(sqd);
+		}
+
+		io_req_caches_free(ctx);
+
+		if (WARN_ON_ONCE(time_after(jiffies, timeout))) {
+			/* there is little hope left, don't run it too often */
+			interval = HZ * 60;
+		}
+	} while (!wait_for_completion_timeout(&ctx->ref_comp, interval));
+
+	init_completion(&exit.completion);
+	init_task_work(&exit.task_work, io_tctx_exit_cb);
+	exit.ctx = ctx;
+	/*
+	 * Some may use context even when all refs and requests have been put,
+	 * and they are free to do so while still holding uring_lock or
+	 * completion_lock, see io_req_task_submit(). Apart from other work,
+	 * this lock/unlock section also waits them to finish.
+	 */
+	mutex_lock(&ctx->uring_lock);
+	while (!list_empty(&ctx->tctx_list)) {
+		WARN_ON_ONCE(time_after(jiffies, timeout));
+
+		node = list_first_entry(&ctx->tctx_list, struct io_tctx_node,
+					ctx_node);
+		/* don't spin on a single task if cancellation failed */
+		list_rotate_left(&ctx->tctx_list);
+		ret = task_work_add(node->task, &exit.task_work, TWA_SIGNAL);
+		if (WARN_ON_ONCE(ret))
+			continue;
+
+		mutex_unlock(&ctx->uring_lock);
+		wait_for_completion(&exit.completion);
+		mutex_lock(&ctx->uring_lock);
+	}
+	mutex_unlock(&ctx->uring_lock);
+	spin_lock(&ctx->completion_lock);
+	spin_unlock(&ctx->completion_lock);
+
+	io_ring_ctx_free(ctx);
+}
+
+/* Returns true if we found and killed one or more timeouts */
+static __cold bool io_kill_timeouts(struct io_ring_ctx *ctx,
+				    struct task_struct *tsk, bool cancel_all)
+{
+	struct io_kiocb *req, *tmp;
+	int canceled = 0;
+
+	spin_lock(&ctx->completion_lock);
+	spin_lock_irq(&ctx->timeout_lock);
+	list_for_each_entry_safe(req, tmp, &ctx->timeout_list, timeout.list) {
+		if (io_match_task(req, tsk, cancel_all)) {
+			io_kill_timeout(req, -ECANCELED);
+			canceled++;
+		}
+	}
+	spin_unlock_irq(&ctx->timeout_lock);
+	io_commit_cqring(ctx);
+	spin_unlock(&ctx->completion_lock);
+	if (canceled != 0)
+		io_cqring_ev_posted(ctx);
+	return canceled != 0;
+}
+
+static __cold void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx)
+{
+	unsigned long index;
+	struct creds *creds;
+
+	mutex_lock(&ctx->uring_lock);
+	percpu_ref_kill(&ctx->refs);
+	if (ctx->rings)
+		__io_cqring_overflow_flush(ctx, true);
+	xa_for_each(&ctx->personalities, index, creds)
+		io_unregister_personality(ctx, index);
+	mutex_unlock(&ctx->uring_lock);
+
+	/* failed during ring init, it couldn't have issued any requests */
+	if (ctx->rings) {
+		io_kill_timeouts(ctx, NULL, true);
+		io_poll_remove_all(ctx, NULL, true);
+		/* if we failed setting up the ctx, we might not have any rings */
+		io_iopoll_try_reap_events(ctx);
+	}
+
+	INIT_WORK(&ctx->exit_work, io_ring_exit_work);
+	/*
+	 * Use system_unbound_wq to avoid spawning tons of event kworkers
+	 * if we're exiting a ton of rings at the same time. It just adds
+	 * noise and overhead, there's no discernable change in runtime
+	 * over using system_wq.
+	 */
+	queue_work(system_unbound_wq, &ctx->exit_work);
+}
+
+static int io_uring_release(struct inode *inode, struct file *file)
+{
+	struct io_ring_ctx *ctx = file->private_data;
+
+	file->private_data = NULL;
+	io_ring_ctx_wait_and_kill(ctx);
+	return 0;
+}
+
+struct io_task_cancel {
+	struct task_struct *task;
+	bool all;
+};
+
+static bool io_cancel_task_cb(struct io_wq_work *work, void *data)
+{
+	struct io_kiocb *req = container_of(work, struct io_kiocb, work);
+	struct io_task_cancel *cancel = data;
+
+	return io_match_task_safe(req, cancel->task, cancel->all);
+}
+
+static __cold bool io_cancel_defer_files(struct io_ring_ctx *ctx,
+					 struct task_struct *task,
+					 bool cancel_all)
+{
+	struct io_defer_entry *de;
+	LIST_HEAD(list);
+
+	spin_lock(&ctx->completion_lock);
+	list_for_each_entry_reverse(de, &ctx->defer_list, list) {
+		if (io_match_task_safe(de->req, task, cancel_all)) {
+			list_cut_position(&list, &ctx->defer_list, &de->list);
+			break;
+		}
+	}
+	spin_unlock(&ctx->completion_lock);
+	if (list_empty(&list))
+		return false;
+
+	while (!list_empty(&list)) {
+		de = list_first_entry(&list, struct io_defer_entry, list);
+		list_del_init(&de->list);
+		io_req_complete_failed(de->req, -ECANCELED);
+		kfree(de);
+	}
+	return true;
+}
+
+static __cold bool io_uring_try_cancel_iowq(struct io_ring_ctx *ctx)
+{
+	struct io_tctx_node *node;
+	enum io_wq_cancel cret;
+	bool ret = false;
+
+	mutex_lock(&ctx->uring_lock);
+	list_for_each_entry(node, &ctx->tctx_list, ctx_node) {
+		struct io_uring_task *tctx = node->task->io_uring;
+
+		/*
+		 * io_wq will stay alive while we hold uring_lock, because it's
+		 * killed after ctx nodes, which requires to take the lock.
+		 */
+		if (!tctx || !tctx->io_wq)
+			continue;
+		cret = io_wq_cancel_cb(tctx->io_wq, io_cancel_ctx_cb, ctx, true);
+		ret |= (cret != IO_WQ_CANCEL_NOTFOUND);
+	}
+	mutex_unlock(&ctx->uring_lock);
+
+	return ret;
+}
+
+static __cold void io_uring_try_cancel_requests(struct io_ring_ctx *ctx,
+						struct task_struct *task,
+						bool cancel_all)
+{
+	struct io_task_cancel cancel = { .task = task, .all = cancel_all, };
+	struct io_uring_task *tctx = task ? task->io_uring : NULL;
+
+	/* failed during ring init, it couldn't have issued any requests */
+	if (!ctx->rings)
+		return;
+
+	while (1) {
+		enum io_wq_cancel cret;
+		bool ret = false;
+
+		if (!task) {
+			ret |= io_uring_try_cancel_iowq(ctx);
+		} else if (tctx && tctx->io_wq) {
+			/*
+			 * Cancels requests of all rings, not only @ctx, but
+			 * it's fine as the task is in exit/exec.
+			 */
+			cret = io_wq_cancel_cb(tctx->io_wq, io_cancel_task_cb,
+					       &cancel, true);
+			ret |= (cret != IO_WQ_CANCEL_NOTFOUND);
+		}
+
+		/* SQPOLL thread does its own polling */
+		if ((!(ctx->flags & IORING_SETUP_SQPOLL) && cancel_all) ||
+		    (ctx->sq_data && ctx->sq_data->thread == current)) {
+			while (!wq_list_empty(&ctx->iopoll_list)) {
+				io_iopoll_try_reap_events(ctx);
+				ret = true;
+			}
+		}
+
+		ret |= io_cancel_defer_files(ctx, task, cancel_all);
+		ret |= io_poll_remove_all(ctx, task, cancel_all);
+		ret |= io_kill_timeouts(ctx, task, cancel_all);
+		if (task)
+			ret |= io_run_task_work();
+		if (!ret)
+			break;
+		cond_resched();
+	}
+}
+
+static int __io_uring_add_tctx_node(struct io_ring_ctx *ctx)
+{
+	struct io_uring_task *tctx = current->io_uring;
+	struct io_tctx_node *node;
+	int ret;
+
+	if (unlikely(!tctx)) {
+		ret = io_uring_alloc_task_context(current, ctx);
+		if (unlikely(ret))
+			return ret;
+
+		tctx = current->io_uring;
+		if (ctx->iowq_limits_set) {
+			unsigned int limits[2] = { ctx->iowq_limits[0],
+						   ctx->iowq_limits[1], };
+
+			ret = io_wq_max_workers(tctx->io_wq, limits);
+			if (ret)
+				return ret;
+		}
+	}
+	if (!xa_load(&tctx->xa, (unsigned long)ctx)) {
+		node = kmalloc(sizeof(*node), GFP_KERNEL);
+		if (!node)
+			return -ENOMEM;
+		node->ctx = ctx;
+		node->task = current;
+
+		ret = xa_err(xa_store(&tctx->xa, (unsigned long)ctx,
+					node, GFP_KERNEL));
+		if (ret) {
+			kfree(node);
+			return ret;
+		}
+
+		mutex_lock(&ctx->uring_lock);
+		list_add(&node->ctx_node, &ctx->tctx_list);
+		mutex_unlock(&ctx->uring_lock);
+	}
+	tctx->last = ctx;
+	return 0;
+}
+
+/*
+ * Note that this task has used io_uring. We use it for cancelation purposes.
+ */
+static inline int io_uring_add_tctx_node(struct io_ring_ctx *ctx)
+{
+	struct io_uring_task *tctx = current->io_uring;
+
+	if (likely(tctx && tctx->last == ctx))
+		return 0;
+	return __io_uring_add_tctx_node(ctx);
+}
+
+/*
+ * Remove this io_uring_file -> task mapping.
+ */
+static __cold void io_uring_del_tctx_node(unsigned long index)
+{
+	struct io_uring_task *tctx = current->io_uring;
+	struct io_tctx_node *node;
+
+	if (!tctx)
+		return;
+	node = xa_erase(&tctx->xa, index);
+	if (!node)
+		return;
+
+	WARN_ON_ONCE(current != node->task);
+	WARN_ON_ONCE(list_empty(&node->ctx_node));
+
+	mutex_lock(&node->ctx->uring_lock);
+	list_del(&node->ctx_node);
+	mutex_unlock(&node->ctx->uring_lock);
+
+	if (tctx->last == node->ctx)
+		tctx->last = NULL;
+	kfree(node);
+}
+
+static __cold void io_uring_clean_tctx(struct io_uring_task *tctx)
+{
+	struct io_wq *wq = tctx->io_wq;
+	struct io_tctx_node *node;
+	unsigned long index;
+
+	xa_for_each(&tctx->xa, index, node) {
+		io_uring_del_tctx_node(index);
+		cond_resched();
+	}
+	if (wq) {
+		/*
+		 * Must be after io_uring_del_tctx_node() (removes nodes under
+		 * uring_lock) to avoid race with io_uring_try_cancel_iowq().
+		 */
+		io_wq_put_and_exit(wq);
+		tctx->io_wq = NULL;
+	}
+}
+
+static s64 tctx_inflight(struct io_uring_task *tctx, bool tracked)
+{
+	if (tracked)
+		return atomic_read(&tctx->inflight_tracked);
+	return percpu_counter_sum(&tctx->inflight);
+}
+
+/*
+ * Find any io_uring ctx that this task has registered or done IO on, and cancel
+ * requests. @sqd should be not-null IFF it's an SQPOLL thread cancellation.
+ */
+static __cold void io_uring_cancel_generic(bool cancel_all,
+					   struct io_sq_data *sqd)
+{
+	struct io_uring_task *tctx = current->io_uring;
+	struct io_ring_ctx *ctx;
+	s64 inflight;
+	DEFINE_WAIT(wait);
+
+	WARN_ON_ONCE(sqd && sqd->thread != current);
+
+	if (!current->io_uring)
+		return;
+	if (tctx->io_wq)
+		io_wq_exit_start(tctx->io_wq);
+
+	atomic_inc(&tctx->in_idle);
+	do {
+		io_uring_drop_tctx_refs(current);
+		/* read completions before cancelations */
+		inflight = tctx_inflight(tctx, !cancel_all);
+		if (!inflight)
+			break;
+
+		if (!sqd) {
+			struct io_tctx_node *node;
+			unsigned long index;
+
+			xa_for_each(&tctx->xa, index, node) {
+				/* sqpoll task will cancel all its requests */
+				if (node->ctx->sq_data)
+					continue;
+				io_uring_try_cancel_requests(node->ctx, current,
+							     cancel_all);
+			}
+		} else {
+			list_for_each_entry(ctx, &sqd->ctx_list, sqd_list)
+				io_uring_try_cancel_requests(ctx, current,
+							     cancel_all);
+		}
+
+		prepare_to_wait(&tctx->wait, &wait, TASK_INTERRUPTIBLE);
+		io_run_task_work();
+		io_uring_drop_tctx_refs(current);
+
+		/*
+		 * If we've seen completions, retry without waiting. This
+		 * avoids a race where a completion comes in before we did
+		 * prepare_to_wait().
+		 */
+		if (inflight == tctx_inflight(tctx, !cancel_all))
+			schedule();
+		finish_wait(&tctx->wait, &wait);
+	} while (1);
+
+	io_uring_clean_tctx(tctx);
+	if (cancel_all) {
+		/*
+		 * We shouldn't run task_works after cancel, so just leave
+		 * ->in_idle set for normal exit.
+		 */
+		atomic_dec(&tctx->in_idle);
+		/* for exec all current's requests should be gone, kill tctx */
+		__io_uring_free(current);
+	}
+}
+
+void __io_uring_cancel(bool cancel_all)
+{
+	io_uring_cancel_generic(cancel_all, NULL);
+}
+
+void io_uring_unreg_ringfd(void)
+{
+	struct io_uring_task *tctx = current->io_uring;
+	int i;
+
+	for (i = 0; i < IO_RINGFD_REG_MAX; i++) {
+		if (tctx->registered_rings[i]) {
+			fput(tctx->registered_rings[i]);
+			tctx->registered_rings[i] = NULL;
+		}
+	}
+}
+
+static int io_ring_add_registered_fd(struct io_uring_task *tctx, int fd,
+				     int start, int end)
+{
+	struct file *file;
+	int offset;
+
+	for (offset = start; offset < end; offset++) {
+		offset = array_index_nospec(offset, IO_RINGFD_REG_MAX);
+		if (tctx->registered_rings[offset])
+			continue;
+
+		file = fget(fd);
+		if (!file) {
+			return -EBADF;
+		} else if (file->f_op != &io_uring_fops) {
+			fput(file);
+			return -EOPNOTSUPP;
+		}
+		tctx->registered_rings[offset] = file;
+		return offset;
+	}
+
+	return -EBUSY;
+}
+
+/*
+ * Register a ring fd to avoid fdget/fdput for each io_uring_enter()
+ * invocation. User passes in an array of struct io_uring_rsrc_update
+ * with ->data set to the ring_fd, and ->offset given for the desired
+ * index. If no index is desired, application may set ->offset == -1U
+ * and we'll find an available index. Returns number of entries
+ * successfully processed, or < 0 on error if none were processed.
+ */
+static int io_ringfd_register(struct io_ring_ctx *ctx, void __user *__arg,
+			      unsigned nr_args)
+{
+	struct io_uring_rsrc_update __user *arg = __arg;
+	struct io_uring_rsrc_update reg;
+	struct io_uring_task *tctx;
+	int ret, i;
+
+	if (!nr_args || nr_args > IO_RINGFD_REG_MAX)
+		return -EINVAL;
+
+	mutex_unlock(&ctx->uring_lock);
+	ret = io_uring_add_tctx_node(ctx);
+	mutex_lock(&ctx->uring_lock);
+	if (ret)
+		return ret;
+
+	tctx = current->io_uring;
+	for (i = 0; i < nr_args; i++) {
+		int start, end;
+
+		if (copy_from_user(&reg, &arg[i], sizeof(reg))) {
+			ret = -EFAULT;
+			break;
+		}
+
+		if (reg.resv) {
+			ret = -EINVAL;
+			break;
+		}
+
+		if (reg.offset == -1U) {
+			start = 0;
+			end = IO_RINGFD_REG_MAX;
+		} else {
+			if (reg.offset >= IO_RINGFD_REG_MAX) {
+				ret = -EINVAL;
+				break;
+			}
+			start = reg.offset;
+			end = start + 1;
+		}
+
+		ret = io_ring_add_registered_fd(tctx, reg.data, start, end);
+		if (ret < 0)
+			break;
+
+		reg.offset = ret;
+		if (copy_to_user(&arg[i], &reg, sizeof(reg))) {
+			fput(tctx->registered_rings[reg.offset]);
+			tctx->registered_rings[reg.offset] = NULL;
+			ret = -EFAULT;
+			break;
+		}
+	}
+
+	return i ? i : ret;
+}
+
+static int io_ringfd_unregister(struct io_ring_ctx *ctx, void __user *__arg,
+				unsigned nr_args)
+{
+	struct io_uring_rsrc_update __user *arg = __arg;
+	struct io_uring_task *tctx = current->io_uring;
+	struct io_uring_rsrc_update reg;
+	int ret = 0, i;
+
+	if (!nr_args || nr_args > IO_RINGFD_REG_MAX)
+		return -EINVAL;
+	if (!tctx)
+		return 0;
+
+	for (i = 0; i < nr_args; i++) {
+		if (copy_from_user(&reg, &arg[i], sizeof(reg))) {
+			ret = -EFAULT;
+			break;
+		}
+		if (reg.resv || reg.data || reg.offset >= IO_RINGFD_REG_MAX) {
+			ret = -EINVAL;
+			break;
+		}
+
+		reg.offset = array_index_nospec(reg.offset, IO_RINGFD_REG_MAX);
+		if (tctx->registered_rings[reg.offset]) {
+			fput(tctx->registered_rings[reg.offset]);
+			tctx->registered_rings[reg.offset] = NULL;
+		}
+	}
+
+	return i ? i : ret;
+}
+
+static void *io_uring_validate_mmap_request(struct file *file,
+					    loff_t pgoff, size_t sz)
+{
+	struct io_ring_ctx *ctx = file->private_data;
+	loff_t offset = pgoff << PAGE_SHIFT;
+	struct page *page;
+	void *ptr;
+
+	switch (offset) {
+	case IORING_OFF_SQ_RING:
+	case IORING_OFF_CQ_RING:
+		ptr = ctx->rings;
+		break;
+	case IORING_OFF_SQES:
+		ptr = ctx->sq_sqes;
+		break;
+	default:
+		return ERR_PTR(-EINVAL);
+	}
+
+	page = virt_to_head_page(ptr);
+	if (sz > page_size(page))
+		return ERR_PTR(-EINVAL);
+
+	return ptr;
+}
+
+#ifdef CONFIG_MMU
+
+static __cold int io_uring_mmap(struct file *file, struct vm_area_struct *vma)
+{
+	size_t sz = vma->vm_end - vma->vm_start;
+	unsigned long pfn;
+	void *ptr;
+
+	ptr = io_uring_validate_mmap_request(file, vma->vm_pgoff, sz);
+	if (IS_ERR(ptr))
+		return PTR_ERR(ptr);
+
+	pfn = virt_to_phys(ptr) >> PAGE_SHIFT;
+	return remap_pfn_range(vma, vma->vm_start, pfn, sz, vma->vm_page_prot);
+}
+
+#else /* !CONFIG_MMU */
+
+static int io_uring_mmap(struct file *file, struct vm_area_struct *vma)
+{
+	return vma->vm_flags & (VM_SHARED | VM_MAYSHARE) ? 0 : -EINVAL;
+}
+
+static unsigned int io_uring_nommu_mmap_capabilities(struct file *file)
+{
+	return NOMMU_MAP_DIRECT | NOMMU_MAP_READ | NOMMU_MAP_WRITE;
+}
+
+static unsigned long io_uring_nommu_get_unmapped_area(struct file *file,
+	unsigned long addr, unsigned long len,
+	unsigned long pgoff, unsigned long flags)
+{
+	void *ptr;
+
+	ptr = io_uring_validate_mmap_request(file, pgoff, len);
+	if (IS_ERR(ptr))
+		return PTR_ERR(ptr);
+
+	return (unsigned long) ptr;
+}
+
+#endif /* !CONFIG_MMU */
+
+static int io_sqpoll_wait_sq(struct io_ring_ctx *ctx)
+{
+	DEFINE_WAIT(wait);
+
+	do {
+		if (!io_sqring_full(ctx))
+			break;
+		prepare_to_wait(&ctx->sqo_sq_wait, &wait, TASK_INTERRUPTIBLE);
+
+		if (!io_sqring_full(ctx))
+			break;
+		schedule();
+	} while (!signal_pending(current));
+
+	finish_wait(&ctx->sqo_sq_wait, &wait);
+	return 0;
+}
+
+static int io_validate_ext_arg(unsigned flags, const void __user *argp, size_t argsz)
+{
+	if (flags & IORING_ENTER_EXT_ARG) {
+		struct io_uring_getevents_arg arg;
+
+		if (argsz != sizeof(arg))
+			return -EINVAL;
+		if (copy_from_user(&arg, argp, sizeof(arg)))
+			return -EFAULT;
+	}
+	return 0;
+}
+
+static int io_get_ext_arg(unsigned flags, const void __user *argp, size_t *argsz,
+			  struct __kernel_timespec __user **ts,
+			  const sigset_t __user **sig)
+{
+	struct io_uring_getevents_arg arg;
+
+	/*
+	 * If EXT_ARG isn't set, then we have no timespec and the argp pointer
+	 * is just a pointer to the sigset_t.
+	 */
+	if (!(flags & IORING_ENTER_EXT_ARG)) {
+		*sig = (const sigset_t __user *) argp;
+		*ts = NULL;
+		return 0;
+	}
+
+	/*
+	 * EXT_ARG is set - ensure we agree on the size of it and copy in our
+	 * timespec and sigset_t pointers if good.
+	 */
+	if (*argsz != sizeof(arg))
+		return -EINVAL;
+	if (copy_from_user(&arg, argp, sizeof(arg)))
+		return -EFAULT;
+	if (arg.pad)
+		return -EINVAL;
+	*sig = u64_to_user_ptr(arg.sigmask);
+	*argsz = arg.sigmask_sz;
+	*ts = u64_to_user_ptr(arg.ts);
+	return 0;
+}
+
+SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit,
+		u32, min_complete, u32, flags, const void __user *, argp,
+		size_t, argsz)
+{
+	struct io_ring_ctx *ctx;
+	struct fd f;
+	long ret;
+
+	io_run_task_work();
+
+	if (unlikely(flags & ~(IORING_ENTER_GETEVENTS | IORING_ENTER_SQ_WAKEUP |
+			       IORING_ENTER_SQ_WAIT | IORING_ENTER_EXT_ARG |
+			       IORING_ENTER_REGISTERED_RING)))
+		return -EINVAL;
+
+	/*
+	 * Ring fd has been registered via IORING_REGISTER_RING_FDS, we
+	 * need only dereference our task private array to find it.
+	 */
+	if (flags & IORING_ENTER_REGISTERED_RING) {
+		struct io_uring_task *tctx = current->io_uring;
+
+		if (!tctx || fd >= IO_RINGFD_REG_MAX)
+			return -EINVAL;
+		fd = array_index_nospec(fd, IO_RINGFD_REG_MAX);
+		f.file = tctx->registered_rings[fd];
+		f.flags = 0;
+	} else {
+		f = fdget(fd);
+	}
+
+	if (unlikely(!f.file))
+		return -EBADF;
+
+	ret = -EOPNOTSUPP;
+	if (unlikely(f.file->f_op != &io_uring_fops))
+		goto out_fput;
+
+	ret = -ENXIO;
+	ctx = f.file->private_data;
+	if (unlikely(!percpu_ref_tryget(&ctx->refs)))
+		goto out_fput;
+
+	ret = -EBADFD;
+	if (unlikely(ctx->flags & IORING_SETUP_R_DISABLED))
+		goto out;
+
+	/*
+	 * For SQ polling, the thread will do all submissions and completions.
+	 * Just return the requested submit count, and wake the thread if
+	 * we were asked to.
+	 */
+	ret = 0;
+	if (ctx->flags & IORING_SETUP_SQPOLL) {
+		io_cqring_overflow_flush(ctx);
+
+		if (unlikely(ctx->sq_data->thread == NULL)) {
+			ret = -EOWNERDEAD;
+			goto out;
+		}
+		if (flags & IORING_ENTER_SQ_WAKEUP)
+			wake_up(&ctx->sq_data->wait);
+		if (flags & IORING_ENTER_SQ_WAIT) {
+			ret = io_sqpoll_wait_sq(ctx);
+			if (ret)
+				goto out;
+		}
+		ret = to_submit;
+	} else if (to_submit) {
+		ret = io_uring_add_tctx_node(ctx);
+		if (unlikely(ret))
+			goto out;
+
+		mutex_lock(&ctx->uring_lock);
+		ret = io_submit_sqes(ctx, to_submit);
+		if (ret != to_submit) {
+			mutex_unlock(&ctx->uring_lock);
+			goto out;
+		}
+		if ((flags & IORING_ENTER_GETEVENTS) && ctx->syscall_iopoll)
+			goto iopoll_locked;
+		mutex_unlock(&ctx->uring_lock);
+	}
+	if (flags & IORING_ENTER_GETEVENTS) {
+		int ret2;
+		if (ctx->syscall_iopoll) {
+			/*
+			 * We disallow the app entering submit/complete with
+			 * polling, but we still need to lock the ring to
+			 * prevent racing with polled issue that got punted to
+			 * a workqueue.
+			 */
+			mutex_lock(&ctx->uring_lock);
+iopoll_locked:
+			ret2 = io_validate_ext_arg(flags, argp, argsz);
+			if (likely(!ret2)) {
+				min_complete = min(min_complete,
+						   ctx->cq_entries);
+				ret2 = io_iopoll_check(ctx, min_complete);
+			}
+			mutex_unlock(&ctx->uring_lock);
+		} else {
+			const sigset_t __user *sig;
+			struct __kernel_timespec __user *ts;
+
+			ret2 = io_get_ext_arg(flags, argp, &argsz, &ts, &sig);
+			if (likely(!ret2)) {
+				min_complete = min(min_complete,
+						   ctx->cq_entries);
+				ret2 = io_cqring_wait(ctx, min_complete, sig,
+						      argsz, ts);
+			}
+		}
+
+		if (!ret) {
+			ret = ret2;
+
+			/*
+			 * EBADR indicates that one or more CQE were dropped.
+			 * Once the user has been informed we can clear the bit
+			 * as they are obviously ok with those drops.
+			 */
+			if (unlikely(ret2 == -EBADR))
+				clear_bit(IO_CHECK_CQ_DROPPED_BIT,
+					  &ctx->check_cq);
+		}
+	}
+
+out:
+	percpu_ref_put(&ctx->refs);
+out_fput:
+	fdput(f);
+	return ret;
+}
+
+#ifdef CONFIG_PROC_FS
+static __cold int io_uring_show_cred(struct seq_file *m, unsigned int id,
+		const struct cred *cred)
+{
+	struct user_namespace *uns = seq_user_ns(m);
+	struct group_info *gi;
+	kernel_cap_t cap;
+	unsigned __capi;
+	int g;
+
+	seq_printf(m, "%5d\n", id);
+	seq_put_decimal_ull(m, "\tUid:\t", from_kuid_munged(uns, cred->uid));
+	seq_put_decimal_ull(m, "\t\t", from_kuid_munged(uns, cred->euid));
+	seq_put_decimal_ull(m, "\t\t", from_kuid_munged(uns, cred->suid));
+	seq_put_decimal_ull(m, "\t\t", from_kuid_munged(uns, cred->fsuid));
+	seq_put_decimal_ull(m, "\n\tGid:\t", from_kgid_munged(uns, cred->gid));
+	seq_put_decimal_ull(m, "\t\t", from_kgid_munged(uns, cred->egid));
+	seq_put_decimal_ull(m, "\t\t", from_kgid_munged(uns, cred->sgid));
+	seq_put_decimal_ull(m, "\t\t", from_kgid_munged(uns, cred->fsgid));
+	seq_puts(m, "\n\tGroups:\t");
+	gi = cred->group_info;
+	for (g = 0; g < gi->ngroups; g++) {
+		seq_put_decimal_ull(m, g ? " " : "",
+					from_kgid_munged(uns, gi->gid[g]));
+	}
+	seq_puts(m, "\n\tCapEff:\t");
+	cap = cred->cap_effective;
+	CAP_FOR_EACH_U32(__capi)
+		seq_put_hex_ll(m, NULL, cap.cap[CAP_LAST_U32 - __capi], 8);
+	seq_putc(m, '\n');
+	return 0;
+}
+
+static __cold void __io_uring_show_fdinfo(struct io_ring_ctx *ctx,
+					  struct seq_file *m)
+{
+	struct io_sq_data *sq = NULL;
+	struct io_overflow_cqe *ocqe;
+	struct io_rings *r = ctx->rings;
+	unsigned int sq_mask = ctx->sq_entries - 1, cq_mask = ctx->cq_entries - 1;
+	unsigned int sq_head = READ_ONCE(r->sq.head);
+	unsigned int sq_tail = READ_ONCE(r->sq.tail);
+	unsigned int cq_head = READ_ONCE(r->cq.head);
+	unsigned int cq_tail = READ_ONCE(r->cq.tail);
+	unsigned int cq_shift = 0;
+	unsigned int sq_entries, cq_entries;
+	bool has_lock;
+	bool is_cqe32 = (ctx->flags & IORING_SETUP_CQE32);
+	unsigned int i;
+
+	if (is_cqe32)
+		cq_shift = 1;
+
+	/*
+	 * we may get imprecise sqe and cqe info if uring is actively running
+	 * since we get cached_sq_head and cached_cq_tail without uring_lock
+	 * and sq_tail and cq_head are changed by userspace. But it's ok since
+	 * we usually use these info when it is stuck.
+	 */
+	seq_printf(m, "SqMask:\t0x%x\n", sq_mask);
+	seq_printf(m, "SqHead:\t%u\n", sq_head);
+	seq_printf(m, "SqTail:\t%u\n", sq_tail);
+	seq_printf(m, "CachedSqHead:\t%u\n", ctx->cached_sq_head);
+	seq_printf(m, "CqMask:\t0x%x\n", cq_mask);
+	seq_printf(m, "CqHead:\t%u\n", cq_head);
+	seq_printf(m, "CqTail:\t%u\n", cq_tail);
+	seq_printf(m, "CachedCqTail:\t%u\n", ctx->cached_cq_tail);
+	seq_printf(m, "SQEs:\t%u\n", sq_tail - ctx->cached_sq_head);
+	sq_entries = min(sq_tail - sq_head, ctx->sq_entries);
+	for (i = 0; i < sq_entries; i++) {
+		unsigned int entry = i + sq_head;
+		unsigned int sq_idx = READ_ONCE(ctx->sq_array[entry & sq_mask]);
+		struct io_uring_sqe *sqe;
+
+		if (sq_idx > sq_mask)
+			continue;
+		sqe = &ctx->sq_sqes[sq_idx];
+		seq_printf(m, "%5u: opcode:%d, fd:%d, flags:%x, user_data:%llu\n",
+			   sq_idx, sqe->opcode, sqe->fd, sqe->flags,
+			   sqe->user_data);
+	}
+	seq_printf(m, "CQEs:\t%u\n", cq_tail - cq_head);
+	cq_entries = min(cq_tail - cq_head, ctx->cq_entries);
+	for (i = 0; i < cq_entries; i++) {
+		unsigned int entry = i + cq_head;
+		struct io_uring_cqe *cqe = &r->cqes[(entry & cq_mask) << cq_shift];
+
+		if (!is_cqe32) {
+			seq_printf(m, "%5u: user_data:%llu, res:%d, flag:%x\n",
+			   entry & cq_mask, cqe->user_data, cqe->res,
+			   cqe->flags);
+		} else {
+			seq_printf(m, "%5u: user_data:%llu, res:%d, flag:%x, "
+				"extra1:%llu, extra2:%llu\n",
+				entry & cq_mask, cqe->user_data, cqe->res,
+				cqe->flags, cqe->big_cqe[0], cqe->big_cqe[1]);
+		}
+	}
+
+	/*
+	 * Avoid ABBA deadlock between the seq lock and the io_uring mutex,
+	 * since fdinfo case grabs it in the opposite direction of normal use
+	 * cases. If we fail to get the lock, we just don't iterate any
+	 * structures that could be going away outside the io_uring mutex.
+	 */
+	has_lock = mutex_trylock(&ctx->uring_lock);
+
+	if (has_lock && (ctx->flags & IORING_SETUP_SQPOLL)) {
+		sq = ctx->sq_data;
+		if (!sq->thread)
+			sq = NULL;
+	}
+
+	seq_printf(m, "SqThread:\t%d\n", sq ? task_pid_nr(sq->thread) : -1);
+	seq_printf(m, "SqThreadCpu:\t%d\n", sq ? task_cpu(sq->thread) : -1);
+	seq_printf(m, "UserFiles:\t%u\n", ctx->nr_user_files);
+	for (i = 0; has_lock && i < ctx->nr_user_files; i++) {
+		struct file *f = io_file_from_index(ctx, i);
+
+		if (f)
+			seq_printf(m, "%5u: %s\n", i, file_dentry(f)->d_iname);
+		else
+			seq_printf(m, "%5u: <none>\n", i);
+	}
+	seq_printf(m, "UserBufs:\t%u\n", ctx->nr_user_bufs);
+	for (i = 0; has_lock && i < ctx->nr_user_bufs; i++) {
+		struct io_mapped_ubuf *buf = ctx->user_bufs[i];
+		unsigned int len = buf->ubuf_end - buf->ubuf;
+
+		seq_printf(m, "%5u: 0x%llx/%u\n", i, buf->ubuf, len);
+	}
+	if (has_lock && !xa_empty(&ctx->personalities)) {
+		unsigned long index;
+		const struct cred *cred;
+
+		seq_printf(m, "Personalities:\n");
+		xa_for_each(&ctx->personalities, index, cred)
+			io_uring_show_cred(m, index, cred);
+	}
+	if (has_lock)
+		mutex_unlock(&ctx->uring_lock);
+
+	seq_puts(m, "PollList:\n");
+	spin_lock(&ctx->completion_lock);
+	for (i = 0; i < (1U << ctx->cancel_hash_bits); i++) {
+		struct hlist_head *list = &ctx->cancel_hash[i];
+		struct io_kiocb *req;
+
+		hlist_for_each_entry(req, list, hash_node)
+			seq_printf(m, "  op=%d, task_works=%d\n", req->opcode,
+					task_work_pending(req->task));
+	}
+
+	seq_puts(m, "CqOverflowList:\n");
+	list_for_each_entry(ocqe, &ctx->cq_overflow_list, list) {
+		struct io_uring_cqe *cqe = &ocqe->cqe;
+
+		seq_printf(m, "  user_data=%llu, res=%d, flags=%x\n",
+			   cqe->user_data, cqe->res, cqe->flags);
+
+	}
+
+	spin_unlock(&ctx->completion_lock);
+}
+
+static __cold void io_uring_show_fdinfo(struct seq_file *m, struct file *f)
+{
+	struct io_ring_ctx *ctx = f->private_data;
+
+	if (percpu_ref_tryget(&ctx->refs)) {
+		__io_uring_show_fdinfo(ctx, m);
+		percpu_ref_put(&ctx->refs);
+	}
+}
+#endif
+
+static const struct file_operations io_uring_fops = {
+	.release	= io_uring_release,
+	.mmap		= io_uring_mmap,
+#ifndef CONFIG_MMU
+	.get_unmapped_area = io_uring_nommu_get_unmapped_area,
+	.mmap_capabilities = io_uring_nommu_mmap_capabilities,
+#endif
+	.poll		= io_uring_poll,
+#ifdef CONFIG_PROC_FS
+	.show_fdinfo	= io_uring_show_fdinfo,
+#endif
+};
+
+static __cold int io_allocate_scq_urings(struct io_ring_ctx *ctx,
+					 struct io_uring_params *p)
+{
+	struct io_rings *rings;
+	size_t size, sq_array_offset;
+
+	/* make sure these are sane, as we already accounted them */
+	ctx->sq_entries = p->sq_entries;
+	ctx->cq_entries = p->cq_entries;
+
+	size = rings_size(ctx, p->sq_entries, p->cq_entries, &sq_array_offset);
+	if (size == SIZE_MAX)
+		return -EOVERFLOW;
+
+	rings = io_mem_alloc(size);
+	if (!rings)
+		return -ENOMEM;
+
+	ctx->rings = rings;
+	ctx->sq_array = (u32 *)((char *)rings + sq_array_offset);
+	rings->sq_ring_mask = p->sq_entries - 1;
+	rings->cq_ring_mask = p->cq_entries - 1;
+	rings->sq_ring_entries = p->sq_entries;
+	rings->cq_ring_entries = p->cq_entries;
+
+	if (p->flags & IORING_SETUP_SQE128)
+		size = array_size(2 * sizeof(struct io_uring_sqe), p->sq_entries);
+	else
+		size = array_size(sizeof(struct io_uring_sqe), p->sq_entries);
+	if (size == SIZE_MAX) {
+		io_mem_free(ctx->rings);
+		ctx->rings = NULL;
+		return -EOVERFLOW;
+	}
+
+	ctx->sq_sqes = io_mem_alloc(size);
+	if (!ctx->sq_sqes) {
+		io_mem_free(ctx->rings);
+		ctx->rings = NULL;
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+static int io_uring_install_fd(struct io_ring_ctx *ctx, struct file *file)
+{
+	int ret, fd;
+
+	fd = get_unused_fd_flags(O_RDWR | O_CLOEXEC);
+	if (fd < 0)
+		return fd;
+
+	ret = io_uring_add_tctx_node(ctx);
+	if (ret) {
+		put_unused_fd(fd);
+		return ret;
+	}
+	fd_install(fd, file);
+	return fd;
+}
+
+/*
+ * Allocate an anonymous fd, this is what constitutes the application
+ * visible backing of an io_uring instance. The application mmaps this
+ * fd to gain access to the SQ/CQ ring details. If UNIX sockets are enabled,
+ * we have to tie this fd to a socket for file garbage collection purposes.
+ */
+static struct file *io_uring_get_file(struct io_ring_ctx *ctx)
+{
+	struct file *file;
+#if defined(CONFIG_UNIX)
+	int ret;
+
+	ret = sock_create_kern(&init_net, PF_UNIX, SOCK_RAW, IPPROTO_IP,
+				&ctx->ring_sock);
+	if (ret)
+		return ERR_PTR(ret);
+#endif
+
+	file = anon_inode_getfile_secure("[io_uring]", &io_uring_fops, ctx,
+					 O_RDWR | O_CLOEXEC, NULL);
+#if defined(CONFIG_UNIX)
+	if (IS_ERR(file)) {
+		sock_release(ctx->ring_sock);
+		ctx->ring_sock = NULL;
+	} else {
+		ctx->ring_sock->file = file;
+	}
+#endif
+	return file;
+}
+
+static __cold int io_uring_create(unsigned entries, struct io_uring_params *p,
+				  struct io_uring_params __user *params)
+{
+	struct io_ring_ctx *ctx;
+	struct file *file;
+	int ret;
+
+	if (!entries)
+		return -EINVAL;
+	if (entries > IORING_MAX_ENTRIES) {
+		if (!(p->flags & IORING_SETUP_CLAMP))
+			return -EINVAL;
+		entries = IORING_MAX_ENTRIES;
+	}
+
+	/*
+	 * Use twice as many entries for the CQ ring. It's possible for the
+	 * application to drive a higher depth than the size of the SQ ring,
+	 * since the sqes are only used at submission time. This allows for
+	 * some flexibility in overcommitting a bit. If the application has
+	 * set IORING_SETUP_CQSIZE, it will have passed in the desired number
+	 * of CQ ring entries manually.
+	 */
+	p->sq_entries = roundup_pow_of_two(entries);
+	if (p->flags & IORING_SETUP_CQSIZE) {
+		/*
+		 * If IORING_SETUP_CQSIZE is set, we do the same roundup
+		 * to a power-of-two, if it isn't already. We do NOT impose
+		 * any cq vs sq ring sizing.
+		 */
+		if (!p->cq_entries)
+			return -EINVAL;
+		if (p->cq_entries > IORING_MAX_CQ_ENTRIES) {
+			if (!(p->flags & IORING_SETUP_CLAMP))
+				return -EINVAL;
+			p->cq_entries = IORING_MAX_CQ_ENTRIES;
+		}
+		p->cq_entries = roundup_pow_of_two(p->cq_entries);
+		if (p->cq_entries < p->sq_entries)
+			return -EINVAL;
+	} else {
+		p->cq_entries = 2 * p->sq_entries;
+	}
+
+	ctx = io_ring_ctx_alloc(p);
+	if (!ctx)
+		return -ENOMEM;
+
+	/*
+	 * When SETUP_IOPOLL and SETUP_SQPOLL are both enabled, user
+	 * space applications don't need to do io completion events
+	 * polling again, they can rely on io_sq_thread to do polling
+	 * work, which can reduce cpu usage and uring_lock contention.
+	 */
+	if (ctx->flags & IORING_SETUP_IOPOLL &&
+	    !(ctx->flags & IORING_SETUP_SQPOLL))
+		ctx->syscall_iopoll = 1;
+
+	ctx->compat = in_compat_syscall();
+	if (!capable(CAP_IPC_LOCK))
+		ctx->user = get_uid(current_user());
+
+	/*
+	 * For SQPOLL, we just need a wakeup, always. For !SQPOLL, if
+	 * COOP_TASKRUN is set, then IPIs are never needed by the app.
+	 */
+	ret = -EINVAL;
+	if (ctx->flags & IORING_SETUP_SQPOLL) {
+		/* IPI related flags don't make sense with SQPOLL */
+		if (ctx->flags & (IORING_SETUP_COOP_TASKRUN |
+				  IORING_SETUP_TASKRUN_FLAG))
+			goto err;
+		ctx->notify_method = TWA_SIGNAL_NO_IPI;
+	} else if (ctx->flags & IORING_SETUP_COOP_TASKRUN) {
+		ctx->notify_method = TWA_SIGNAL_NO_IPI;
+	} else {
+		if (ctx->flags & IORING_SETUP_TASKRUN_FLAG)
+			goto err;
+		ctx->notify_method = TWA_SIGNAL;
+	}
+
+	/*
+	 * This is just grabbed for accounting purposes. When a process exits,
+	 * the mm is exited and dropped before the files, hence we need to hang
+	 * on to this mm purely for the purposes of being able to unaccount
+	 * memory (locked/pinned vm). It's not used for anything else.
+	 */
+	mmgrab(current->mm);
+	ctx->mm_account = current->mm;
+
+	ret = io_allocate_scq_urings(ctx, p);
+	if (ret)
+		goto err;
+
+	ret = io_sq_offload_create(ctx, p);
+	if (ret)
+		goto err;
+	/* always set a rsrc node */
+	ret = io_rsrc_node_switch_start(ctx);
+	if (ret)
+		goto err;
+	io_rsrc_node_switch(ctx, NULL);
+
+	memset(&p->sq_off, 0, sizeof(p->sq_off));
+	p->sq_off.head = offsetof(struct io_rings, sq.head);
+	p->sq_off.tail = offsetof(struct io_rings, sq.tail);
+	p->sq_off.ring_mask = offsetof(struct io_rings, sq_ring_mask);
+	p->sq_off.ring_entries = offsetof(struct io_rings, sq_ring_entries);
+	p->sq_off.flags = offsetof(struct io_rings, sq_flags);
+	p->sq_off.dropped = offsetof(struct io_rings, sq_dropped);
+	p->sq_off.array = (char *)ctx->sq_array - (char *)ctx->rings;
+
+	memset(&p->cq_off, 0, sizeof(p->cq_off));
+	p->cq_off.head = offsetof(struct io_rings, cq.head);
+	p->cq_off.tail = offsetof(struct io_rings, cq.tail);
+	p->cq_off.ring_mask = offsetof(struct io_rings, cq_ring_mask);
+	p->cq_off.ring_entries = offsetof(struct io_rings, cq_ring_entries);
+	p->cq_off.overflow = offsetof(struct io_rings, cq_overflow);
+	p->cq_off.cqes = offsetof(struct io_rings, cqes);
+	p->cq_off.flags = offsetof(struct io_rings, cq_flags);
+
+	p->features = IORING_FEAT_SINGLE_MMAP | IORING_FEAT_NODROP |
+			IORING_FEAT_SUBMIT_STABLE | IORING_FEAT_RW_CUR_POS |
+			IORING_FEAT_CUR_PERSONALITY | IORING_FEAT_FAST_POLL |
+			IORING_FEAT_POLL_32BITS | IORING_FEAT_SQPOLL_NONFIXED |
+			IORING_FEAT_EXT_ARG | IORING_FEAT_NATIVE_WORKERS |
+			IORING_FEAT_RSRC_TAGS | IORING_FEAT_CQE_SKIP |
+			IORING_FEAT_LINKED_FILE;
+
+	if (copy_to_user(params, p, sizeof(*p))) {
+		ret = -EFAULT;
+		goto err;
+	}
+
+	file = io_uring_get_file(ctx);
+	if (IS_ERR(file)) {
+		ret = PTR_ERR(file);
+		goto err;
+	}
+
+	/*
+	 * Install ring fd as the very last thing, so we don't risk someone
+	 * having closed it before we finish setup
+	 */
+	ret = io_uring_install_fd(ctx, file);
+	if (ret < 0) {
+		/* fput will clean it up */
+		fput(file);
+		return ret;
+	}
+
+	trace_io_uring_create(ret, ctx, p->sq_entries, p->cq_entries, p->flags);
+	return ret;
+err:
+	io_ring_ctx_wait_and_kill(ctx);
+	return ret;
+}
+
+/*
+ * Sets up an aio uring context, and returns the fd. Applications asks for a
+ * ring size, we return the actual sq/cq ring sizes (among other things) in the
+ * params structure passed in.
+ */
+static long io_uring_setup(u32 entries, struct io_uring_params __user *params)
+{
+	struct io_uring_params p;
+	int i;
+
+	if (copy_from_user(&p, params, sizeof(p)))
+		return -EFAULT;
+	for (i = 0; i < ARRAY_SIZE(p.resv); i++) {
+		if (p.resv[i])
+			return -EINVAL;
+	}
+
+	if (p.flags & ~(IORING_SETUP_IOPOLL | IORING_SETUP_SQPOLL |
+			IORING_SETUP_SQ_AFF | IORING_SETUP_CQSIZE |
+			IORING_SETUP_CLAMP | IORING_SETUP_ATTACH_WQ |
+			IORING_SETUP_R_DISABLED | IORING_SETUP_SUBMIT_ALL |
+			IORING_SETUP_COOP_TASKRUN | IORING_SETUP_TASKRUN_FLAG |
+			IORING_SETUP_SQE128 | IORING_SETUP_CQE32))
+		return -EINVAL;
+
+	return io_uring_create(entries, &p, params);
+}
+
+SYSCALL_DEFINE2(io_uring_setup, u32, entries,
+		struct io_uring_params __user *, params)
+{
+	return io_uring_setup(entries, params);
+}
+
+static __cold int io_probe(struct io_ring_ctx *ctx, void __user *arg,
+			   unsigned nr_args)
+{
+	struct io_uring_probe *p;
+	size_t size;
+	int i, ret;
+
+	size = struct_size(p, ops, nr_args);
+	if (size == SIZE_MAX)
+		return -EOVERFLOW;
+	p = kzalloc(size, GFP_KERNEL);
+	if (!p)
+		return -ENOMEM;
+
+	ret = -EFAULT;
+	if (copy_from_user(p, arg, size))
+		goto out;
+	ret = -EINVAL;
+	if (memchr_inv(p, 0, size))
+		goto out;
+
+	p->last_op = IORING_OP_LAST - 1;
+	if (nr_args > IORING_OP_LAST)
+		nr_args = IORING_OP_LAST;
+
+	for (i = 0; i < nr_args; i++) {
+		p->ops[i].op = i;
+		if (!io_op_defs[i].not_supported)
+			p->ops[i].flags = IO_URING_OP_SUPPORTED;
+	}
+	p->ops_len = i;
+
+	ret = 0;
+	if (copy_to_user(arg, p, size))
+		ret = -EFAULT;
+out:
+	kfree(p);
+	return ret;
+}
+
+static int io_register_personality(struct io_ring_ctx *ctx)
+{
+	const struct cred *creds;
+	u32 id;
+	int ret;
+
+	creds = get_current_cred();
+
+	ret = xa_alloc_cyclic(&ctx->personalities, &id, (void *)creds,
+			XA_LIMIT(0, USHRT_MAX), &ctx->pers_next, GFP_KERNEL);
+	if (ret < 0) {
+		put_cred(creds);
+		return ret;
+	}
+	return id;
+}
+
+static __cold int io_register_restrictions(struct io_ring_ctx *ctx,
+					   void __user *arg, unsigned int nr_args)
+{
+	struct io_uring_restriction *res;
+	size_t size;
+	int i, ret;
+
+	/* Restrictions allowed only if rings started disabled */
+	if (!(ctx->flags & IORING_SETUP_R_DISABLED))
+		return -EBADFD;
+
+	/* We allow only a single restrictions registration */
+	if (ctx->restrictions.registered)
+		return -EBUSY;
+
+	if (!arg || nr_args > IORING_MAX_RESTRICTIONS)
+		return -EINVAL;
+
+	size = array_size(nr_args, sizeof(*res));
+	if (size == SIZE_MAX)
+		return -EOVERFLOW;
+
+	res = memdup_user(arg, size);
+	if (IS_ERR(res))
+		return PTR_ERR(res);
+
+	ret = 0;
+
+	for (i = 0; i < nr_args; i++) {
+		switch (res[i].opcode) {
+		case IORING_RESTRICTION_REGISTER_OP:
+			if (res[i].register_op >= IORING_REGISTER_LAST) {
+				ret = -EINVAL;
+				goto out;
+			}
+
+			__set_bit(res[i].register_op,
+				  ctx->restrictions.register_op);
+			break;
+		case IORING_RESTRICTION_SQE_OP:
+			if (res[i].sqe_op >= IORING_OP_LAST) {
+				ret = -EINVAL;
+				goto out;
+			}
+
+			__set_bit(res[i].sqe_op, ctx->restrictions.sqe_op);
+			break;
+		case IORING_RESTRICTION_SQE_FLAGS_ALLOWED:
+			ctx->restrictions.sqe_flags_allowed = res[i].sqe_flags;
+			break;
+		case IORING_RESTRICTION_SQE_FLAGS_REQUIRED:
+			ctx->restrictions.sqe_flags_required = res[i].sqe_flags;
+			break;
+		default:
+			ret = -EINVAL;
+			goto out;
+		}
+	}
+
+out:
+	/* Reset all restrictions if an error happened */
+	if (ret != 0)
+		memset(&ctx->restrictions, 0, sizeof(ctx->restrictions));
+	else
+		ctx->restrictions.registered = true;
+
+	kfree(res);
+	return ret;
+}
+
+static int io_register_enable_rings(struct io_ring_ctx *ctx)
+{
+	if (!(ctx->flags & IORING_SETUP_R_DISABLED))
+		return -EBADFD;
+
+	if (ctx->restrictions.registered)
+		ctx->restricted = 1;
+
+	ctx->flags &= ~IORING_SETUP_R_DISABLED;
+	if (ctx->sq_data && wq_has_sleeper(&ctx->sq_data->wait))
+		wake_up(&ctx->sq_data->wait);
+	return 0;
+}
+
+static int __io_register_rsrc_update(struct io_ring_ctx *ctx, unsigned type,
+				     struct io_uring_rsrc_update2 *up,
+				     unsigned nr_args)
+{
+	__u32 tmp;
+	int err;
+
+	if (check_add_overflow(up->offset, nr_args, &tmp))
+		return -EOVERFLOW;
+	err = io_rsrc_node_switch_start(ctx);
+	if (err)
+		return err;
+
+	switch (type) {
+	case IORING_RSRC_FILE:
+		return __io_sqe_files_update(ctx, up, nr_args);
+	case IORING_RSRC_BUFFER:
+		return __io_sqe_buffers_update(ctx, up, nr_args);
+	}
+	return -EINVAL;
+}
+
+static int io_register_files_update(struct io_ring_ctx *ctx, void __user *arg,
+				    unsigned nr_args)
+{
+	struct io_uring_rsrc_update2 up;
+
+	if (!nr_args)
+		return -EINVAL;
+	memset(&up, 0, sizeof(up));
+	if (copy_from_user(&up, arg, sizeof(struct io_uring_rsrc_update)))
+		return -EFAULT;
+	if (up.resv || up.resv2)
+		return -EINVAL;
+	return __io_register_rsrc_update(ctx, IORING_RSRC_FILE, &up, nr_args);
+}
+
+static int io_register_rsrc_update(struct io_ring_ctx *ctx, void __user *arg,
+				   unsigned size, unsigned type)
+{
+	struct io_uring_rsrc_update2 up;
+
+	if (size != sizeof(up))
+		return -EINVAL;
+	if (copy_from_user(&up, arg, sizeof(up)))
+		return -EFAULT;
+	if (!up.nr || up.resv || up.resv2)
+		return -EINVAL;
+	return __io_register_rsrc_update(ctx, type, &up, up.nr);
+}
+
+static __cold int io_register_rsrc(struct io_ring_ctx *ctx, void __user *arg,
+			    unsigned int size, unsigned int type)
+{
+	struct io_uring_rsrc_register rr;
+
+	/* keep it extendible */
+	if (size != sizeof(rr))
+		return -EINVAL;
+
+	memset(&rr, 0, sizeof(rr));
+	if (copy_from_user(&rr, arg, size))
+		return -EFAULT;
+	if (!rr.nr || rr.resv2)
+		return -EINVAL;
+	if (rr.flags & ~IORING_RSRC_REGISTER_SPARSE)
+		return -EINVAL;
+
+	switch (type) {
+	case IORING_RSRC_FILE:
+		if (rr.flags & IORING_RSRC_REGISTER_SPARSE && rr.data)
+			break;
+		return io_sqe_files_register(ctx, u64_to_user_ptr(rr.data),
+					     rr.nr, u64_to_user_ptr(rr.tags));
+	case IORING_RSRC_BUFFER:
+		if (rr.flags & IORING_RSRC_REGISTER_SPARSE && rr.data)
+			break;
+		return io_sqe_buffers_register(ctx, u64_to_user_ptr(rr.data),
+					       rr.nr, u64_to_user_ptr(rr.tags));
+	}
+	return -EINVAL;
+}
+
+static __cold int io_register_iowq_aff(struct io_ring_ctx *ctx,
+				       void __user *arg, unsigned len)
+{
+	struct io_uring_task *tctx = current->io_uring;
+	cpumask_var_t new_mask;
+	int ret;
+
+	if (!tctx || !tctx->io_wq)
+		return -EINVAL;
+
+	if (!alloc_cpumask_var(&new_mask, GFP_KERNEL))
+		return -ENOMEM;
+
+	cpumask_clear(new_mask);
+	if (len > cpumask_size())
+		len = cpumask_size();
+
+	if (in_compat_syscall()) {
+		ret = compat_get_bitmap(cpumask_bits(new_mask),
+					(const compat_ulong_t __user *)arg,
+					len * 8 /* CHAR_BIT */);
+	} else {
+		ret = copy_from_user(new_mask, arg, len);
+	}
+
+	if (ret) {
+		free_cpumask_var(new_mask);
+		return -EFAULT;
+	}
+
+	ret = io_wq_cpu_affinity(tctx->io_wq, new_mask);
+	free_cpumask_var(new_mask);
+	return ret;
+}
+
+static __cold int io_unregister_iowq_aff(struct io_ring_ctx *ctx)
+{
+	struct io_uring_task *tctx = current->io_uring;
+
+	if (!tctx || !tctx->io_wq)
+		return -EINVAL;
+
+	return io_wq_cpu_affinity(tctx->io_wq, NULL);
+}
+
+static __cold int io_register_iowq_max_workers(struct io_ring_ctx *ctx,
+					       void __user *arg)
+	__must_hold(&ctx->uring_lock)
+{
+	struct io_tctx_node *node;
+	struct io_uring_task *tctx = NULL;
+	struct io_sq_data *sqd = NULL;
+	__u32 new_count[2];
+	int i, ret;
+
+	if (copy_from_user(new_count, arg, sizeof(new_count)))
+		return -EFAULT;
+	for (i = 0; i < ARRAY_SIZE(new_count); i++)
+		if (new_count[i] > INT_MAX)
+			return -EINVAL;
+
+	if (ctx->flags & IORING_SETUP_SQPOLL) {
+		sqd = ctx->sq_data;
+		if (sqd) {
+			/*
+			 * Observe the correct sqd->lock -> ctx->uring_lock
+			 * ordering. Fine to drop uring_lock here, we hold
+			 * a ref to the ctx.
+			 */
+			refcount_inc(&sqd->refs);
+			mutex_unlock(&ctx->uring_lock);
+			mutex_lock(&sqd->lock);
+			mutex_lock(&ctx->uring_lock);
+			if (sqd->thread)
+				tctx = sqd->thread->io_uring;
+		}
+	} else {
+		tctx = current->io_uring;
+	}
+
+	BUILD_BUG_ON(sizeof(new_count) != sizeof(ctx->iowq_limits));
+
+	for (i = 0; i < ARRAY_SIZE(new_count); i++)
+		if (new_count[i])
+			ctx->iowq_limits[i] = new_count[i];
+	ctx->iowq_limits_set = true;
+
+	if (tctx && tctx->io_wq) {
+		ret = io_wq_max_workers(tctx->io_wq, new_count);
+		if (ret)
+			goto err;
+	} else {
+		memset(new_count, 0, sizeof(new_count));
+	}
+
+	if (sqd) {
+		mutex_unlock(&sqd->lock);
+		io_put_sq_data(sqd);
+	}
+
+	if (copy_to_user(arg, new_count, sizeof(new_count)))
+		return -EFAULT;
+
+	/* that's it for SQPOLL, only the SQPOLL task creates requests */
+	if (sqd)
+		return 0;
+
+	/* now propagate the restriction to all registered users */
+	list_for_each_entry(node, &ctx->tctx_list, ctx_node) {
+		struct io_uring_task *tctx = node->task->io_uring;
+
+		if (WARN_ON_ONCE(!tctx->io_wq))
+			continue;
+
+		for (i = 0; i < ARRAY_SIZE(new_count); i++)
+			new_count[i] = ctx->iowq_limits[i];
+		/* ignore errors, it always returns zero anyway */
+		(void)io_wq_max_workers(tctx->io_wq, new_count);
+	}
+	return 0;
+err:
+	if (sqd) {
+		mutex_unlock(&sqd->lock);
+		io_put_sq_data(sqd);
+	}
+	return ret;
+}
+
+static int io_register_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg)
+{
+	struct io_uring_buf_ring *br;
+	struct io_uring_buf_reg reg;
+	struct io_buffer_list *bl, *free_bl = NULL;
+	struct page **pages;
+	int nr_pages;
+
+	if (copy_from_user(&reg, arg, sizeof(reg)))
+		return -EFAULT;
+
+	if (reg.pad || reg.resv[0] || reg.resv[1] || reg.resv[2])
+		return -EINVAL;
+	if (!reg.ring_addr)
+		return -EFAULT;
+	if (reg.ring_addr & ~PAGE_MASK)
+		return -EINVAL;
+	if (!is_power_of_2(reg.ring_entries))
+		return -EINVAL;
+
+	/* cannot disambiguate full vs empty due to head/tail size */
+	if (reg.ring_entries >= 65536)
+		return -EINVAL;
+
+	if (unlikely(reg.bgid < BGID_ARRAY && !ctx->io_bl)) {
+		int ret = io_init_bl_list(ctx);
+		if (ret)
+			return ret;
+	}
+
+	bl = io_buffer_get_list(ctx, reg.bgid);
+	if (bl) {
+		/* if mapped buffer ring OR classic exists, don't allow */
+		if (bl->buf_nr_pages || !list_empty(&bl->buf_list))
+			return -EEXIST;
+	} else {
+		free_bl = bl = kzalloc(sizeof(*bl), GFP_KERNEL);
+		if (!bl)
+			return -ENOMEM;
+	}
+
+	pages = io_pin_pages(reg.ring_addr,
+			     struct_size(br, bufs, reg.ring_entries),
+			     &nr_pages);
+	if (IS_ERR(pages)) {
+		kfree(free_bl);
+		return PTR_ERR(pages);
+	}
+
+	br = page_address(pages[0]);
+	bl->buf_pages = pages;
+	bl->buf_nr_pages = nr_pages;
+	bl->nr_entries = reg.ring_entries;
+	bl->buf_ring = br;
+	bl->mask = reg.ring_entries - 1;
+	io_buffer_add_list(ctx, bl, reg.bgid);
+	return 0;
+}
+
+static int io_unregister_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg)
+{
+	struct io_uring_buf_reg reg;
+	struct io_buffer_list *bl;
+
+	if (copy_from_user(&reg, arg, sizeof(reg)))
+		return -EFAULT;
+	if (reg.pad || reg.resv[0] || reg.resv[1] || reg.resv[2])
+		return -EINVAL;
+
+	bl = io_buffer_get_list(ctx, reg.bgid);
+	if (!bl)
+		return -ENOENT;
+	if (!bl->buf_nr_pages)
+		return -EINVAL;
+
+	__io_remove_buffers(ctx, bl, -1U);
+	if (bl->bgid >= BGID_ARRAY) {
+		xa_erase(&ctx->io_bl_xa, bl->bgid);
+		kfree(bl);
+	}
+	return 0;
+}
+
+static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode,
+			       void __user *arg, unsigned nr_args)
+	__releases(ctx->uring_lock)
+	__acquires(ctx->uring_lock)
+{
+	int ret;
+
+	/*
+	 * We're inside the ring mutex, if the ref is already dying, then
+	 * someone else killed the ctx or is already going through
+	 * io_uring_register().
+	 */
+	if (percpu_ref_is_dying(&ctx->refs))
+		return -ENXIO;
+
+	if (ctx->restricted) {
+		if (opcode >= IORING_REGISTER_LAST)
+			return -EINVAL;
+		opcode = array_index_nospec(opcode, IORING_REGISTER_LAST);
+		if (!test_bit(opcode, ctx->restrictions.register_op))
+			return -EACCES;
+	}
+
+	switch (opcode) {
+	case IORING_REGISTER_BUFFERS:
+		ret = -EFAULT;
+		if (!arg)
+			break;
+		ret = io_sqe_buffers_register(ctx, arg, nr_args, NULL);
+		break;
+	case IORING_UNREGISTER_BUFFERS:
+		ret = -EINVAL;
+		if (arg || nr_args)
+			break;
+		ret = io_sqe_buffers_unregister(ctx);
+		break;
+	case IORING_REGISTER_FILES:
+		ret = -EFAULT;
+		if (!arg)
+			break;
+		ret = io_sqe_files_register(ctx, arg, nr_args, NULL);
+		break;
+	case IORING_UNREGISTER_FILES:
+		ret = -EINVAL;
+		if (arg || nr_args)
+			break;
+		ret = io_sqe_files_unregister(ctx);
+		break;
+	case IORING_REGISTER_FILES_UPDATE:
+		ret = io_register_files_update(ctx, arg, nr_args);
+		break;
+	case IORING_REGISTER_EVENTFD:
+		ret = -EINVAL;
+		if (nr_args != 1)
+			break;
+		ret = io_eventfd_register(ctx, arg, 0);
+		break;
+	case IORING_REGISTER_EVENTFD_ASYNC:
+		ret = -EINVAL;
+		if (nr_args != 1)
+			break;
+		ret = io_eventfd_register(ctx, arg, 1);
+		break;
+	case IORING_UNREGISTER_EVENTFD:
+		ret = -EINVAL;
+		if (arg || nr_args)
+			break;
+		ret = io_eventfd_unregister(ctx);
+		break;
+	case IORING_REGISTER_PROBE:
+		ret = -EINVAL;
+		if (!arg || nr_args > 256)
+			break;
+		ret = io_probe(ctx, arg, nr_args);
+		break;
+	case IORING_REGISTER_PERSONALITY:
+		ret = -EINVAL;
+		if (arg || nr_args)
+			break;
+		ret = io_register_personality(ctx);
+		break;
+	case IORING_UNREGISTER_PERSONALITY:
+		ret = -EINVAL;
+		if (arg)
+			break;
+		ret = io_unregister_personality(ctx, nr_args);
+		break;
+	case IORING_REGISTER_ENABLE_RINGS:
+		ret = -EINVAL;
+		if (arg || nr_args)
+			break;
+		ret = io_register_enable_rings(ctx);
+		break;
+	case IORING_REGISTER_RESTRICTIONS:
+		ret = io_register_restrictions(ctx, arg, nr_args);
+		break;
+	case IORING_REGISTER_FILES2:
+		ret = io_register_rsrc(ctx, arg, nr_args, IORING_RSRC_FILE);
+		break;
+	case IORING_REGISTER_FILES_UPDATE2:
+		ret = io_register_rsrc_update(ctx, arg, nr_args,
+					      IORING_RSRC_FILE);
+		break;
+	case IORING_REGISTER_BUFFERS2:
+		ret = io_register_rsrc(ctx, arg, nr_args, IORING_RSRC_BUFFER);
+		break;
+	case IORING_REGISTER_BUFFERS_UPDATE:
+		ret = io_register_rsrc_update(ctx, arg, nr_args,
+					      IORING_RSRC_BUFFER);
+		break;
+	case IORING_REGISTER_IOWQ_AFF:
+		ret = -EINVAL;
+		if (!arg || !nr_args)
+			break;
+		ret = io_register_iowq_aff(ctx, arg, nr_args);
+		break;
+	case IORING_UNREGISTER_IOWQ_AFF:
+		ret = -EINVAL;
+		if (arg || nr_args)
+			break;
+		ret = io_unregister_iowq_aff(ctx);
+		break;
+	case IORING_REGISTER_IOWQ_MAX_WORKERS:
+		ret = -EINVAL;
+		if (!arg || nr_args != 2)
+			break;
+		ret = io_register_iowq_max_workers(ctx, arg);
+		break;
+	case IORING_REGISTER_RING_FDS:
+		ret = io_ringfd_register(ctx, arg, nr_args);
+		break;
+	case IORING_UNREGISTER_RING_FDS:
+		ret = io_ringfd_unregister(ctx, arg, nr_args);
+		break;
+	case IORING_REGISTER_PBUF_RING:
+		ret = -EINVAL;
+		if (!arg || nr_args != 1)
+			break;
+		ret = io_register_pbuf_ring(ctx, arg);
+		break;
+	case IORING_UNREGISTER_PBUF_RING:
+		ret = -EINVAL;
+		if (!arg || nr_args != 1)
+			break;
+		ret = io_unregister_pbuf_ring(ctx, arg);
+		break;
+	default:
+		ret = -EINVAL;
+		break;
+	}
+
+	return ret;
+}
+
+SYSCALL_DEFINE4(io_uring_register, unsigned int, fd, unsigned int, opcode,
+		void __user *, arg, unsigned int, nr_args)
+{
+	struct io_ring_ctx *ctx;
+	long ret = -EBADF;
+	struct fd f;
+
+	f = fdget(fd);
+	if (!f.file)
+		return -EBADF;
+
+	ret = -EOPNOTSUPP;
+	if (f.file->f_op != &io_uring_fops)
+		goto out_fput;
+
+	ctx = f.file->private_data;
+
+	io_run_task_work();
+
+	mutex_lock(&ctx->uring_lock);
+	ret = __io_uring_register(ctx, opcode, arg, nr_args);
+	mutex_unlock(&ctx->uring_lock);
+	trace_io_uring_register(ctx, opcode, ctx->nr_user_files, ctx->nr_user_bufs, ret);
+out_fput:
+	fdput(f);
+	return ret;
+}
+
+static int io_no_issue(struct io_kiocb *req, unsigned int issue_flags)
+{
+	WARN_ON_ONCE(1);
+	return -ECANCELED;
+}
+
+static const struct io_op_def io_op_defs[] = {
+	[IORING_OP_NOP] = {
+		.audit_skip		= 1,
+		.iopoll			= 1,
+		.prep			= io_nop_prep,
+		.issue			= io_nop,
+	},
+	[IORING_OP_READV] = {
+		.needs_file		= 1,
+		.unbound_nonreg_file	= 1,
+		.pollin			= 1,
+		.buffer_select		= 1,
+		.needs_async_setup	= 1,
+		.plug			= 1,
+		.audit_skip		= 1,
+		.ioprio			= 1,
+		.iopoll			= 1,
+		.async_size		= sizeof(struct io_async_rw),
+		.prep			= io_prep_rw,
+		.issue			= io_read,
+	},
+	[IORING_OP_WRITEV] = {
+		.needs_file		= 1,
+		.hash_reg_file		= 1,
+		.unbound_nonreg_file	= 1,
+		.pollout		= 1,
+		.needs_async_setup	= 1,
+		.plug			= 1,
+		.audit_skip		= 1,
+		.ioprio			= 1,
+		.iopoll			= 1,
+		.async_size		= sizeof(struct io_async_rw),
+		.prep			= io_prep_rw,
+		.issue			= io_write,
+	},
+	[IORING_OP_FSYNC] = {
+		.needs_file		= 1,
+		.audit_skip		= 1,
+		.prep			= io_fsync_prep,
+		.issue			= io_fsync,
+	},
+	[IORING_OP_READ_FIXED] = {
+		.needs_file		= 1,
+		.unbound_nonreg_file	= 1,
+		.pollin			= 1,
+		.plug			= 1,
+		.audit_skip		= 1,
+		.ioprio			= 1,
+		.iopoll			= 1,
+		.async_size		= sizeof(struct io_async_rw),
+		.prep			= io_prep_rw,
+		.issue			= io_read,
+	},
+	[IORING_OP_WRITE_FIXED] = {
+		.needs_file		= 1,
+		.hash_reg_file		= 1,
+		.unbound_nonreg_file	= 1,
+		.pollout		= 1,
+		.plug			= 1,
+		.audit_skip		= 1,
+		.ioprio			= 1,
+		.iopoll			= 1,
+		.async_size		= sizeof(struct io_async_rw),
+		.prep			= io_prep_rw,
+		.issue			= io_write,
+	},
+	[IORING_OP_POLL_ADD] = {
+		.needs_file		= 1,
+		.unbound_nonreg_file	= 1,
+		.audit_skip		= 1,
+		.prep			= io_poll_add_prep,
+		.issue			= io_poll_add,
+	},
+	[IORING_OP_POLL_REMOVE] = {
+		.audit_skip		= 1,
+		.prep			= io_poll_remove_prep,
+		.issue			= io_poll_remove,
+	},
+	[IORING_OP_SYNC_FILE_RANGE] = {
+		.needs_file		= 1,
+		.audit_skip		= 1,
+		.prep			= io_sfr_prep,
+		.issue			= io_sync_file_range,
+	},
+	[IORING_OP_SENDMSG] = {
+		.needs_file		= 1,
+		.unbound_nonreg_file	= 1,
+		.pollout		= 1,
+		.needs_async_setup	= 1,
+		.ioprio			= 1,
+		.async_size		= sizeof(struct io_async_msghdr),
+		.prep			= io_sendmsg_prep,
+		.issue			= io_sendmsg,
+	},
+	[IORING_OP_RECVMSG] = {
+		.needs_file		= 1,
+		.unbound_nonreg_file	= 1,
+		.pollin			= 1,
+		.buffer_select		= 1,
+		.needs_async_setup	= 1,
+		.ioprio			= 1,
+		.async_size		= sizeof(struct io_async_msghdr),
+		.prep			= io_recvmsg_prep,
+		.issue			= io_recvmsg,
+	},
+	[IORING_OP_TIMEOUT] = {
+		.audit_skip		= 1,
+		.async_size		= sizeof(struct io_timeout_data),
+		.prep			= io_timeout_prep,
+		.issue			= io_timeout,
+	},
+	[IORING_OP_TIMEOUT_REMOVE] = {
+		/* used by timeout updates' prep() */
+		.audit_skip		= 1,
+		.prep			= io_timeout_remove_prep,
+		.issue			= io_timeout_remove,
+	},
+	[IORING_OP_ACCEPT] = {
+		.needs_file		= 1,
+		.unbound_nonreg_file	= 1,
+		.pollin			= 1,
+		.poll_exclusive		= 1,
+		.ioprio			= 1,	/* used for flags */
+		.prep			= io_accept_prep,
+		.issue			= io_accept,
+	},
+	[IORING_OP_ASYNC_CANCEL] = {
+		.audit_skip		= 1,
+		.prep			= io_async_cancel_prep,
+		.issue			= io_async_cancel,
+	},
+	[IORING_OP_LINK_TIMEOUT] = {
+		.audit_skip		= 1,
+		.async_size		= sizeof(struct io_timeout_data),
+		.prep			= io_link_timeout_prep,
+		.issue			= io_no_issue,
+	},
+	[IORING_OP_CONNECT] = {
+		.needs_file		= 1,
+		.unbound_nonreg_file	= 1,
+		.pollout		= 1,
+		.needs_async_setup	= 1,
+		.async_size		= sizeof(struct io_async_connect),
+		.prep			= io_connect_prep,
+		.issue			= io_connect,
+	},
+	[IORING_OP_FALLOCATE] = {
+		.needs_file		= 1,
+		.prep			= io_fallocate_prep,
+		.issue			= io_fallocate,
+	},
+	[IORING_OP_OPENAT] = {
+		.prep			= io_openat_prep,
+		.issue			= io_openat,
+	},
+	[IORING_OP_CLOSE] = {
+		.prep			= io_close_prep,
+		.issue			= io_close,
+	},
+	[IORING_OP_FILES_UPDATE] = {
+		.audit_skip		= 1,
+		.iopoll			= 1,
+		.prep			= io_files_update_prep,
+		.issue			= io_files_update,
+	},
+	[IORING_OP_STATX] = {
+		.audit_skip		= 1,
+		.prep			= io_statx_prep,
+		.issue			= io_statx,
+	},
+	[IORING_OP_READ] = {
+		.needs_file		= 1,
+		.unbound_nonreg_file	= 1,
+		.pollin			= 1,
+		.buffer_select		= 1,
+		.plug			= 1,
+		.audit_skip		= 1,
+		.ioprio			= 1,
+		.iopoll			= 1,
+		.async_size		= sizeof(struct io_async_rw),
+		.prep			= io_prep_rw,
+		.issue			= io_read,
+	},
+	[IORING_OP_WRITE] = {
+		.needs_file		= 1,
+		.hash_reg_file		= 1,
+		.unbound_nonreg_file	= 1,
+		.pollout		= 1,
+		.plug			= 1,
+		.audit_skip		= 1,
+		.ioprio			= 1,
+		.iopoll			= 1,
+		.async_size		= sizeof(struct io_async_rw),
+		.prep			= io_prep_rw,
+		.issue			= io_write,
+	},
+	[IORING_OP_FADVISE] = {
+		.needs_file		= 1,
+		.audit_skip		= 1,
+		.prep			= io_fadvise_prep,
+		.issue			= io_fadvise,
+	},
+	[IORING_OP_MADVISE] = {
+		.prep			= io_madvise_prep,
+		.issue			= io_madvise,
+	},
+	[IORING_OP_SEND] = {
+		.needs_file		= 1,
+		.unbound_nonreg_file	= 1,
+		.pollout		= 1,
+		.audit_skip		= 1,
+		.ioprio			= 1,
+		.prep			= io_sendmsg_prep,
+		.issue			= io_send,
+	},
+	[IORING_OP_RECV] = {
+		.needs_file		= 1,
+		.unbound_nonreg_file	= 1,
+		.pollin			= 1,
+		.buffer_select		= 1,
+		.audit_skip		= 1,
+		.ioprio			= 1,
+		.prep			= io_recvmsg_prep,
+		.issue			= io_recv,
+	},
+	[IORING_OP_OPENAT2] = {
+		.prep			= io_openat2_prep,
+		.issue			= io_openat2,
+	},
+	[IORING_OP_EPOLL_CTL] = {
+		.unbound_nonreg_file	= 1,
+		.audit_skip		= 1,
+		.prep			= io_epoll_ctl_prep,
+		.issue			= io_epoll_ctl,
+	},
+	[IORING_OP_SPLICE] = {
+		.needs_file		= 1,
+		.hash_reg_file		= 1,
+		.unbound_nonreg_file	= 1,
+		.audit_skip		= 1,
+		.prep			= io_splice_prep,
+		.issue			= io_splice,
+	},
+	[IORING_OP_PROVIDE_BUFFERS] = {
+		.audit_skip		= 1,
+		.iopoll			= 1,
+		.prep			= io_provide_buffers_prep,
+		.issue			= io_provide_buffers,
+	},
+	[IORING_OP_REMOVE_BUFFERS] = {
+		.audit_skip		= 1,
+		.iopoll			= 1,
+		.prep			= io_remove_buffers_prep,
+		.issue			= io_remove_buffers,
+	},
+	[IORING_OP_TEE] = {
+		.needs_file		= 1,
+		.hash_reg_file		= 1,
+		.unbound_nonreg_file	= 1,
+		.audit_skip		= 1,
+		.prep			= io_tee_prep,
+		.issue			= io_tee,
+	},
+	[IORING_OP_SHUTDOWN] = {
+		.needs_file		= 1,
+		.prep			= io_shutdown_prep,
+		.issue			= io_shutdown,
+	},
+	[IORING_OP_RENAMEAT] = {
+		.prep			= io_renameat_prep,
+		.issue			= io_renameat,
+	},
+	[IORING_OP_UNLINKAT] = {
+		.prep			= io_unlinkat_prep,
+		.issue			= io_unlinkat,
+	},
+	[IORING_OP_MKDIRAT] = {
+		.prep			= io_mkdirat_prep,
+		.issue			= io_mkdirat,
+	},
+	[IORING_OP_SYMLINKAT] = {
+		.prep			= io_symlinkat_prep,
+		.issue			= io_symlinkat,
+	},
+	[IORING_OP_LINKAT] = {
+		.prep			= io_linkat_prep,
+		.issue			= io_linkat,
+	},
+	[IORING_OP_MSG_RING] = {
+		.needs_file		= 1,
+		.iopoll			= 1,
+		.prep			= io_msg_ring_prep,
+		.issue			= io_msg_ring,
+	},
+	[IORING_OP_FSETXATTR] = {
+		.needs_file = 1,
+		.prep			= io_fsetxattr_prep,
+		.issue			= io_fsetxattr,
+	},
+	[IORING_OP_SETXATTR] = {
+		.prep			= io_setxattr_prep,
+		.issue			= io_setxattr,
+	},
+	[IORING_OP_FGETXATTR] = {
+		.needs_file = 1,
+		.prep			= io_fgetxattr_prep,
+		.issue			= io_fgetxattr,
+	},
+	[IORING_OP_GETXATTR] = {
+		.prep			= io_getxattr_prep,
+		.issue			= io_getxattr,
+	},
+	[IORING_OP_SOCKET] = {
+		.audit_skip		= 1,
+		.prep			= io_socket_prep,
+		.issue			= io_socket,
+	},
+	[IORING_OP_URING_CMD] = {
+		.needs_file		= 1,
+		.plug			= 1,
+		.needs_async_setup	= 1,
+		.async_size		= uring_cmd_pdu_size(1),
+		.prep			= io_uring_cmd_prep,
+		.issue			= io_uring_cmd,
+	},
+};
+
+static int __init io_uring_init(void)
+{
+	int i;
+
+#define __BUILD_BUG_VERIFY_ELEMENT(stype, eoffset, etype, ename) do { \
+	BUILD_BUG_ON(offsetof(stype, ename) != eoffset); \
+	BUILD_BUG_ON(sizeof(etype) != sizeof_field(stype, ename)); \
+} while (0)
+
+#define BUILD_BUG_SQE_ELEM(eoffset, etype, ename) \
+	__BUILD_BUG_VERIFY_ELEMENT(struct io_uring_sqe, eoffset, etype, ename)
+	BUILD_BUG_ON(sizeof(struct io_uring_sqe) != 64);
+	BUILD_BUG_SQE_ELEM(0,  __u8,   opcode);
+	BUILD_BUG_SQE_ELEM(1,  __u8,   flags);
+	BUILD_BUG_SQE_ELEM(2,  __u16,  ioprio);
+	BUILD_BUG_SQE_ELEM(4,  __s32,  fd);
+	BUILD_BUG_SQE_ELEM(8,  __u64,  off);
+	BUILD_BUG_SQE_ELEM(8,  __u64,  addr2);
+	BUILD_BUG_SQE_ELEM(16, __u64,  addr);
+	BUILD_BUG_SQE_ELEM(16, __u64,  splice_off_in);
+	BUILD_BUG_SQE_ELEM(24, __u32,  len);
+	BUILD_BUG_SQE_ELEM(28,     __kernel_rwf_t, rw_flags);
+	BUILD_BUG_SQE_ELEM(28, /* compat */   int, rw_flags);
+	BUILD_BUG_SQE_ELEM(28, /* compat */ __u32, rw_flags);
+	BUILD_BUG_SQE_ELEM(28, __u32,  fsync_flags);
+	BUILD_BUG_SQE_ELEM(28, /* compat */ __u16,  poll_events);
+	BUILD_BUG_SQE_ELEM(28, __u32,  poll32_events);
+	BUILD_BUG_SQE_ELEM(28, __u32,  sync_range_flags);
+	BUILD_BUG_SQE_ELEM(28, __u32,  msg_flags);
+	BUILD_BUG_SQE_ELEM(28, __u32,  timeout_flags);
+	BUILD_BUG_SQE_ELEM(28, __u32,  accept_flags);
+	BUILD_BUG_SQE_ELEM(28, __u32,  cancel_flags);
+	BUILD_BUG_SQE_ELEM(28, __u32,  open_flags);
+	BUILD_BUG_SQE_ELEM(28, __u32,  statx_flags);
+	BUILD_BUG_SQE_ELEM(28, __u32,  fadvise_advice);
+	BUILD_BUG_SQE_ELEM(28, __u32,  splice_flags);
+	BUILD_BUG_SQE_ELEM(32, __u64,  user_data);
+	BUILD_BUG_SQE_ELEM(40, __u16,  buf_index);
+	BUILD_BUG_SQE_ELEM(40, __u16,  buf_group);
+	BUILD_BUG_SQE_ELEM(42, __u16,  personality);
+	BUILD_BUG_SQE_ELEM(44, __s32,  splice_fd_in);
+	BUILD_BUG_SQE_ELEM(44, __u32,  file_index);
+	BUILD_BUG_SQE_ELEM(48, __u64,  addr3);
+
+	BUILD_BUG_ON(sizeof(struct io_uring_files_update) !=
+		     sizeof(struct io_uring_rsrc_update));
+	BUILD_BUG_ON(sizeof(struct io_uring_rsrc_update) >
+		     sizeof(struct io_uring_rsrc_update2));
+
+	/* ->buf_index is u16 */
+	BUILD_BUG_ON(IORING_MAX_REG_BUFFERS >= (1u << 16));
+	BUILD_BUG_ON(BGID_ARRAY * sizeof(struct io_buffer_list) > PAGE_SIZE);
+	BUILD_BUG_ON(offsetof(struct io_uring_buf_ring, bufs) != 0);
+	BUILD_BUG_ON(offsetof(struct io_uring_buf, resv) !=
+		     offsetof(struct io_uring_buf_ring, tail));
+
+	/* should fit into one byte */
+	BUILD_BUG_ON(SQE_VALID_FLAGS >= (1 << 8));
+	BUILD_BUG_ON(SQE_COMMON_FLAGS >= (1 << 8));
+	BUILD_BUG_ON((SQE_VALID_FLAGS | SQE_COMMON_FLAGS) != SQE_VALID_FLAGS);
+
+	BUILD_BUG_ON(ARRAY_SIZE(io_op_defs) != IORING_OP_LAST);
+	BUILD_BUG_ON(__REQ_F_LAST_BIT > 8 * sizeof(int));
+
+	BUILD_BUG_ON(sizeof(atomic_t) != sizeof(u32));
+
+	BUILD_BUG_ON(sizeof(struct io_uring_cmd) > 64);
+
+	for (i = 0; i < ARRAY_SIZE(io_op_defs); i++) {
+		BUG_ON(!io_op_defs[i].prep);
+		BUG_ON(!io_op_defs[i].issue);
+	}
+
+	req_cachep = KMEM_CACHE(io_kiocb, SLAB_HWCACHE_ALIGN | SLAB_PANIC |
+				SLAB_ACCOUNT);
+	return 0;
+};
+__initcall(io_uring_init);