fsi: Add regmap and refactor sbefifo

Merge series from Eddie James <eajames@linux.ibm.com>:

The SBEFIFO hardware can now be attached over a new I2C endpoint interface
called the I2C Responder (I2CR). In order to use the existing SBEFIFO
driver, add a regmap driver for the FSI bus and an endpoint driver for the
I2CR. Then, refactor the SBEFIFO and OCC drivers to clean up and use the
new regmap driver or the I2CR interface.

This branch just has the regmap change so it can be shared with the FSI
code.

1 files changed, 21 insertions, 26 deletions

diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index de08d9902b30..8840cf3e20f2 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -176,6 +176,11 @@ static inline unsigned int __io_cqring_events(struct io_ring_ctx *ctx)
 	return ctx->cached_cq_tail - READ_ONCE(ctx->rings->cq.head);
 }
 
+static inline unsigned int __io_cqring_events_user(struct io_ring_ctx *ctx)
+{
+	return READ_ONCE(ctx->rings->cq.tail) - READ_ONCE(ctx->rings->cq.head);
+}
+
 static bool io_match_linked(struct io_kiocb *head)
 {
 	struct io_kiocb *req;
@@ -1173,7 +1178,7 @@ static void __cold io_move_task_work_from_local(struct io_ring_ctx *ctx)
 	}
 }
 
-int __io_run_local_work(struct io_ring_ctx *ctx, bool locked)
+int __io_run_local_work(struct io_ring_ctx *ctx, bool *locked)
 {
 	struct llist_node *node;
 	struct llist_node fake;
@@ -1192,7 +1197,7 @@ again:
 		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));
-		req->io_task_work.func(req, &locked);
+		req->io_task_work.func(req, locked);
 		ret++;
 		node = next;
 	}
@@ -1208,7 +1213,7 @@ again:
 		goto again;
 	}
 
-	if (locked)
+	if (*locked)
 		io_submit_flush_completions(ctx);
 	trace_io_uring_local_work_run(ctx, ret, loops);
 	return ret;
@@ -1225,7 +1230,7 @@ int io_run_local_work(struct io_ring_ctx *ctx)
 
 	__set_current_state(TASK_RUNNING);
 	locked = mutex_trylock(&ctx->uring_lock);
-	ret = __io_run_local_work(ctx, locked);
+	ret = __io_run_local_work(ctx, &locked);
 	if (locked)
 		mutex_unlock(&ctx->uring_lock);
 
@@ -1446,8 +1451,7 @@ static int io_iopoll_check(struct io_ring_ctx *ctx, long min)
 		    io_task_work_pending(ctx)) {
 			u32 tail = ctx->cached_cq_tail;
 
-			if (!llist_empty(&ctx->work_llist))
-				__io_run_local_work(ctx, true);
+			(void) io_run_local_work_locked(ctx);
 
 			if (task_work_pending(current) ||
 			    wq_list_empty(&ctx->iopoll_list)) {
@@ -1587,8 +1591,6 @@ unsigned int io_file_get_flags(struct file *file)
 		res |= FFS_ISREG;
 	if (__io_file_supports_nowait(file, mode))
 		res |= FFS_NOWAIT;
-	if (io_file_need_scm(file))
-		res |= FFS_SCM;
 	return res;
 }
 
@@ -1766,7 +1768,7 @@ int io_poll_issue(struct io_kiocb *req, bool *locked)
 	io_tw_lock(req->ctx, locked);
 	if (unlikely(req->task->flags & PF_EXITING))
 		return -EFAULT;
-	return io_issue_sqe(req, IO_URING_F_NONBLOCK);
+	return io_issue_sqe(req, IO_URING_F_NONBLOCK|IO_URING_F_MULTISHOT);
 }
 
 struct io_wq_work *io_wq_free_work(struct io_wq_work *work)
@@ -1860,7 +1862,6 @@ inline struct file *io_file_get_fixed(struct io_kiocb *req, int fd,
 	/* 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;
@@ -2319,7 +2320,7 @@ static inline bool io_has_work(struct io_ring_ctx *ctx)
 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;
+	int dist = READ_ONCE(ctx->rings->cq.tail) - (int) iowq->cq_tail;
 
 	/*
 	 * Wake up if we have enough events, or if a timeout occurred since we
@@ -2403,7 +2404,8 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events,
 			return ret;
 		io_cqring_overflow_flush(ctx);
 
-		if (io_cqring_events(ctx) >= min_events)
+		/* if user messes with these they will just get an early return */
+		if (__io_cqring_events_user(ctx) >= min_events)
 			return 0;
 	} while (ret > 0);
 
@@ -2563,18 +2565,14 @@ static int io_eventfd_unregister(struct io_ring_ctx *ctx)
 
 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);
+	io_flush_cached_locked_reqs(ctx, &ctx->submit_state);
 
 	while (!io_req_cache_empty(ctx)) {
-		struct io_wq_work_node *node;
-		struct io_kiocb *req;
+		struct io_kiocb *req = io_alloc_req(ctx);
 
-		node = wq_stack_extract(&state->free_list);
-		req = container_of(node, struct io_kiocb, comp_list);
 		kmem_cache_free(req_cachep, req);
 		nr++;
 	}
@@ -2811,15 +2809,12 @@ static __cold void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx)
 		io_poll_remove_all(ctx, NULL, true);
 	mutex_unlock(&ctx->uring_lock);
 
-	/* failed during ring init, it couldn't have issued any requests */
-	if (ctx->rings) {
+	/*
+	 * If we failed setting up the ctx, we might not have any rings
+	 * and therefore did not submit any requests
+	 */
+	if (ctx->rings)
 		io_kill_timeouts(ctx, NULL, true);
-		/* if we failed setting up the ctx, we might not have any rings */
-		io_iopoll_try_reap_events(ctx);
-		/* drop cached put refs after potentially doing completions */
-		if (current->io_uring)
-			io_uring_drop_tctx_refs(current);
-	}
 
 	INIT_WORK(&ctx->exit_work, io_ring_exit_work);
 	/*