1 files changed, 361 insertions, 0 deletions

diff --git a/net/xdp/xdp_umem.c b/net/xdp/xdp_umem.c
new file mode 100644
index 000000000000..7eb4948a38d2
--- /dev/null
+++ b/net/xdp/xdp_umem.c
@@ -0,0 +1,361 @@
+// SPDX-License-Identifier: GPL-2.0
+/* XDP user-space packet buffer
+ * Copyright(c) 2018 Intel Corporation.
+ */
+
+#include <linux/init.h>
+#include <linux/sched/mm.h>
+#include <linux/sched/signal.h>
+#include <linux/sched/task.h>
+#include <linux/uaccess.h>
+#include <linux/slab.h>
+#include <linux/bpf.h>
+#include <linux/mm.h>
+
+#include "xdp_umem.h"
+#include "xsk_queue.h"
+
+#define XDP_UMEM_MIN_CHUNK_SIZE 2048
+
+void xdp_add_sk_umem(struct xdp_umem *umem, struct xdp_sock *xs)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&umem->xsk_list_lock, flags);
+	list_add_rcu(&xs->list, &umem->xsk_list);
+	spin_unlock_irqrestore(&umem->xsk_list_lock, flags);
+}
+
+void xdp_del_sk_umem(struct xdp_umem *umem, struct xdp_sock *xs)
+{
+	unsigned long flags;
+
+	if (xs->dev) {
+		spin_lock_irqsave(&umem->xsk_list_lock, flags);
+		list_del_rcu(&xs->list);
+		spin_unlock_irqrestore(&umem->xsk_list_lock, flags);
+
+		if (umem->zc)
+			synchronize_net();
+	}
+}
+
+int xdp_umem_assign_dev(struct xdp_umem *umem, struct net_device *dev,
+			u32 queue_id, u16 flags)
+{
+	bool force_zc, force_copy;
+	struct netdev_bpf bpf;
+	int err;
+
+	force_zc = flags & XDP_ZEROCOPY;
+	force_copy = flags & XDP_COPY;
+
+	if (force_zc && force_copy)
+		return -EINVAL;
+
+	if (force_copy)
+		return 0;
+
+	dev_hold(dev);
+
+	if (dev->netdev_ops->ndo_bpf && dev->netdev_ops->ndo_xsk_async_xmit) {
+		bpf.command = XDP_QUERY_XSK_UMEM;
+
+		rtnl_lock();
+		err = dev->netdev_ops->ndo_bpf(dev, &bpf);
+		rtnl_unlock();
+
+		if (err) {
+			dev_put(dev);
+			return force_zc ? -ENOTSUPP : 0;
+		}
+
+		bpf.command = XDP_SETUP_XSK_UMEM;
+		bpf.xsk.umem = umem;
+		bpf.xsk.queue_id = queue_id;
+
+		rtnl_lock();
+		err = dev->netdev_ops->ndo_bpf(dev, &bpf);
+		rtnl_unlock();
+
+		if (err) {
+			dev_put(dev);
+			return force_zc ? err : 0; /* fail or fallback */
+		}
+
+		umem->dev = dev;
+		umem->queue_id = queue_id;
+		umem->zc = true;
+		return 0;
+	}
+
+	dev_put(dev);
+	return force_zc ? -ENOTSUPP : 0; /* fail or fallback */
+}
+
+static void xdp_umem_clear_dev(struct xdp_umem *umem)
+{
+	struct netdev_bpf bpf;
+	int err;
+
+	if (umem->dev) {
+		bpf.command = XDP_SETUP_XSK_UMEM;
+		bpf.xsk.umem = NULL;
+		bpf.xsk.queue_id = umem->queue_id;
+
+		rtnl_lock();
+		err = umem->dev->netdev_ops->ndo_bpf(umem->dev, &bpf);
+		rtnl_unlock();
+
+		if (err)
+			WARN(1, "failed to disable umem!\n");
+
+		dev_put(umem->dev);
+		umem->dev = NULL;
+	}
+}
+
+static void xdp_umem_unpin_pages(struct xdp_umem *umem)
+{
+	unsigned int i;
+
+	for (i = 0; i < umem->npgs; i++) {
+		struct page *page = umem->pgs[i];
+
+		set_page_dirty_lock(page);
+		put_page(page);
+	}
+
+	kfree(umem->pgs);
+	umem->pgs = NULL;
+}
+
+static void xdp_umem_unaccount_pages(struct xdp_umem *umem)
+{
+	atomic_long_sub(umem->npgs, &umem->user->locked_vm);
+	free_uid(umem->user);
+}
+
+static void xdp_umem_release(struct xdp_umem *umem)
+{
+	struct task_struct *task;
+	struct mm_struct *mm;
+
+	xdp_umem_clear_dev(umem);
+
+	if (umem->fq) {
+		xskq_destroy(umem->fq);
+		umem->fq = NULL;
+	}
+
+	if (umem->cq) {
+		xskq_destroy(umem->cq);
+		umem->cq = NULL;
+	}
+
+	xdp_umem_unpin_pages(umem);
+
+	task = get_pid_task(umem->pid, PIDTYPE_PID);
+	put_pid(umem->pid);
+	if (!task)
+		goto out;
+	mm = get_task_mm(task);
+	put_task_struct(task);
+	if (!mm)
+		goto out;
+
+	mmput(mm);
+	kfree(umem->pages);
+	umem->pages = NULL;
+
+	xdp_umem_unaccount_pages(umem);
+out:
+	kfree(umem);
+}
+
+static void xdp_umem_release_deferred(struct work_struct *work)
+{
+	struct xdp_umem *umem = container_of(work, struct xdp_umem, work);
+
+	xdp_umem_release(umem);
+}
+
+void xdp_get_umem(struct xdp_umem *umem)
+{
+	refcount_inc(&umem->users);
+}
+
+void xdp_put_umem(struct xdp_umem *umem)
+{
+	if (!umem)
+		return;
+
+	if (refcount_dec_and_test(&umem->users)) {
+		INIT_WORK(&umem->work, xdp_umem_release_deferred);
+		schedule_work(&umem->work);
+	}
+}
+
+static int xdp_umem_pin_pages(struct xdp_umem *umem)
+{
+	unsigned int gup_flags = FOLL_WRITE;
+	long npgs;
+	int err;
+
+	umem->pgs = kcalloc(umem->npgs, sizeof(*umem->pgs), GFP_KERNEL);
+	if (!umem->pgs)
+		return -ENOMEM;
+
+	down_write(&current->mm->mmap_sem);
+	npgs = get_user_pages(umem->address, umem->npgs,
+			      gup_flags, &umem->pgs[0], NULL);
+	up_write(&current->mm->mmap_sem);
+
+	if (npgs != umem->npgs) {
+		if (npgs >= 0) {
+			umem->npgs = npgs;
+			err = -ENOMEM;
+			goto out_pin;
+		}
+		err = npgs;
+		goto out_pgs;
+	}
+	return 0;
+
+out_pin:
+	xdp_umem_unpin_pages(umem);
+out_pgs:
+	kfree(umem->pgs);
+	umem->pgs = NULL;
+	return err;
+}
+
+static int xdp_umem_account_pages(struct xdp_umem *umem)
+{
+	unsigned long lock_limit, new_npgs, old_npgs;
+
+	if (capable(CAP_IPC_LOCK))
+		return 0;
+
+	lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
+	umem->user = get_uid(current_user());
+
+	do {
+		old_npgs = atomic_long_read(&umem->user->locked_vm);
+		new_npgs = old_npgs + umem->npgs;
+		if (new_npgs > lock_limit) {
+			free_uid(umem->user);
+			umem->user = NULL;
+			return -ENOBUFS;
+		}
+	} while (atomic_long_cmpxchg(&umem->user->locked_vm, old_npgs,
+				     new_npgs) != old_npgs);
+	return 0;
+}
+
+static int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr)
+{
+	u32 chunk_size = mr->chunk_size, headroom = mr->headroom;
+	unsigned int chunks, chunks_per_page;
+	u64 addr = mr->addr, size = mr->len;
+	int size_chk, err, i;
+
+	if (chunk_size < XDP_UMEM_MIN_CHUNK_SIZE || chunk_size > PAGE_SIZE) {
+		/* Strictly speaking we could support this, if:
+		 * - huge pages, or*
+		 * - using an IOMMU, or
+		 * - making sure the memory area is consecutive
+		 * but for now, we simply say "computer says no".
+		 */
+		return -EINVAL;
+	}
+
+	if (!is_power_of_2(chunk_size))
+		return -EINVAL;
+
+	if (!PAGE_ALIGNED(addr)) {
+		/* Memory area has to be page size aligned. For
+		 * simplicity, this might change.
+		 */
+		return -EINVAL;
+	}
+
+	if ((addr + size) < addr)
+		return -EINVAL;
+
+	chunks = (unsigned int)div_u64(size, chunk_size);
+	if (chunks == 0)
+		return -EINVAL;
+
+	chunks_per_page = PAGE_SIZE / chunk_size;
+	if (chunks < chunks_per_page || chunks % chunks_per_page)
+		return -EINVAL;
+
+	headroom = ALIGN(headroom, 64);
+
+	size_chk = chunk_size - headroom - XDP_PACKET_HEADROOM;
+	if (size_chk < 0)
+		return -EINVAL;
+
+	umem->pid = get_task_pid(current, PIDTYPE_PID);
+	umem->address = (unsigned long)addr;
+	umem->props.chunk_mask = ~((u64)chunk_size - 1);
+	umem->props.size = size;
+	umem->headroom = headroom;
+	umem->chunk_size_nohr = chunk_size - headroom;
+	umem->npgs = size / PAGE_SIZE;
+	umem->pgs = NULL;
+	umem->user = NULL;
+	INIT_LIST_HEAD(&umem->xsk_list);
+	spin_lock_init(&umem->xsk_list_lock);
+
+	refcount_set(&umem->users, 1);
+
+	err = xdp_umem_account_pages(umem);
+	if (err)
+		goto out;
+
+	err = xdp_umem_pin_pages(umem);
+	if (err)
+		goto out_account;
+
+	umem->pages = kcalloc(umem->npgs, sizeof(*umem->pages), GFP_KERNEL);
+	if (!umem->pages) {
+		err = -ENOMEM;
+		goto out_account;
+	}
+
+	for (i = 0; i < umem->npgs; i++)
+		umem->pages[i].addr = page_address(umem->pgs[i]);
+
+	return 0;
+
+out_account:
+	xdp_umem_unaccount_pages(umem);
+out:
+	put_pid(umem->pid);
+	return err;
+}
+
+struct xdp_umem *xdp_umem_create(struct xdp_umem_reg *mr)
+{
+	struct xdp_umem *umem;
+	int err;
+
+	umem = kzalloc(sizeof(*umem), GFP_KERNEL);
+	if (!umem)
+		return ERR_PTR(-ENOMEM);
+
+	err = xdp_umem_reg(umem, mr);
+	if (err) {
+		kfree(umem);
+		return ERR_PTR(err);
+	}
+
+	return umem;
+}
+
+bool xdp_umem_validate_queues(struct xdp_umem *umem)
+{
+	return umem->fq && umem->cq;
+}