4 files changed, 19 insertions, 26 deletions

diff --git a/include/linux/io_uring_types.h b/include/linux/io_uring_types.h
index 9795eda529f7..c0c03d8059df 100644
--- a/include/linux/io_uring_types.h
+++ b/include/linux/io_uring_types.h
@@ -205,6 +205,7 @@ struct io_ring_ctx {
 		unsigned int		has_evfd: 1;
 		/* all CQEs should be posted only by the submitter task */
 		unsigned int		task_complete: 1;
+		unsigned int		lockless_cq: 1;
 		unsigned int		syscall_iopoll: 1;
 		unsigned int		poll_activated: 1;
 		unsigned int		drain_disabled: 1;
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 7c1ef5b6628d..e8321903e3f3 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -147,7 +147,6 @@ static bool io_uring_try_cancel_requests(struct io_ring_ctx *ctx,
 					 bool cancel_all);
 
 static void io_queue_sqe(struct io_kiocb *req);
-static void __io_submit_flush_completions(struct io_ring_ctx *ctx);
 
 struct kmem_cache *req_cachep;
 
@@ -616,7 +615,7 @@ void __io_commit_cqring_flush(struct io_ring_ctx *ctx)
 
 static inline void __io_cq_lock(struct io_ring_ctx *ctx)
 {
-	if (!ctx->task_complete)
+	if (!ctx->lockless_cq)
 		spin_lock(&ctx->completion_lock);
 }
 
@@ -630,8 +629,11 @@ static inline void __io_cq_unlock_post(struct io_ring_ctx *ctx)
 {
 	io_commit_cqring(ctx);
 	if (!ctx->task_complete) {
-		spin_unlock(&ctx->completion_lock);
-		io_cqring_wake(ctx);
+		if (!ctx->lockless_cq)
+			spin_unlock(&ctx->completion_lock);
+		/* IOPOLL rings only need to wake up if it's also SQPOLL */
+		if (!ctx->syscall_iopoll)
+			io_cqring_wake(ctx);
 	}
 	io_commit_cqring_flush(ctx);
 }
@@ -1485,7 +1487,8 @@ void io_queue_next(struct io_kiocb *req)
 		io_req_task_queue(nxt);
 }
 
-void io_free_batch_list(struct io_ring_ctx *ctx, struct io_wq_work_node *node)
+static void io_free_batch_list(struct io_ring_ctx *ctx,
+			       struct io_wq_work_node *node)
 	__must_hold(&ctx->uring_lock)
 {
 	do {
@@ -1522,7 +1525,7 @@ void io_free_batch_list(struct io_ring_ctx *ctx, struct io_wq_work_node *node)
 	} while (node);
 }
 
-static void __io_submit_flush_completions(struct io_ring_ctx *ctx)
+void __io_submit_flush_completions(struct io_ring_ctx *ctx)
 	__must_hold(&ctx->uring_lock)
 {
 	struct io_submit_state *state = &ctx->submit_state;
@@ -3836,6 +3839,9 @@ static __cold int io_uring_create(unsigned entries, struct io_uring_params *p,
 	    !(ctx->flags & IORING_SETUP_SQPOLL))
 		ctx->task_complete = true;
 
+	if (ctx->task_complete || (ctx->flags & IORING_SETUP_IOPOLL))
+		ctx->lockless_cq = true;
+
 	/*
 	 * lazy poll_wq activation relies on ->task_complete for synchronisation
 	 * purposes, see io_activate_pollwq()
diff --git a/io_uring/io_uring.h b/io_uring/io_uring.h
index 2960e35b32a5..07fd185064d2 100644
--- a/io_uring/io_uring.h
+++ b/io_uring/io_uring.h
@@ -72,7 +72,7 @@ int io_ring_add_registered_file(struct io_uring_task *tctx, struct file *file,
 int io_poll_issue(struct io_kiocb *req, struct io_tw_state *ts);
 int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr);
 int io_do_iopoll(struct io_ring_ctx *ctx, bool force_nonspin);
-void io_free_batch_list(struct io_ring_ctx *ctx, struct io_wq_work_node *node);
+void __io_submit_flush_completions(struct io_ring_ctx *ctx);
 int io_req_prep_async(struct io_kiocb *req);
 
 struct io_wq_work *io_wq_free_work(struct io_wq_work *work);
diff --git a/io_uring/rw.c b/io_uring/rw.c
index 20140d3505f1..0a1e515f0510 100644
--- a/io_uring/rw.c
+++ b/io_uring/rw.c
@@ -983,13 +983,6 @@ copy_iov:
 	return ret;
 }
 
-static void io_cqring_ev_posted_iopoll(struct io_ring_ctx *ctx)
-{
-	if (ctx->flags & IORING_SETUP_SQPOLL)
-		io_cqring_wake(ctx);
-	io_commit_cqring_flush(ctx);
-}
-
 void io_rw_fail(struct io_kiocb *req)
 {
 	int res;
@@ -1060,24 +1053,17 @@ int io_do_iopoll(struct io_ring_ctx *ctx, bool force_nonspin)
 		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);
-		if (unlikely(!io_fill_cqe_req(ctx, req))) {
-			spin_lock(&ctx->completion_lock);
-			io_req_cqe_overflow(req);
-			spin_unlock(&ctx->completion_lock);
-		}
 	}
-
 	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);
+
+	if (WARN_ON_ONCE(!wq_list_empty(&ctx->submit_state.compl_reqs)))
+		return 0;
+	ctx->submit_state.compl_reqs.first = pos;
+	__io_submit_flush_completions(ctx);
 	return nr_events;
 }