io_uring: reorder cqring_flush and wakeups

Unlike in the past, io_commit_cqring_flush() doesn't do anything that
may need io_cqring_wake() to be issued after, all requests it completes
will go via task_work. Do io_commit_cqring_flush() after
io_cqring_wake() to clean up __io_cq_unlock_post().

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/ed32dcfeec47e6c97bd6b18c152ddce5b218403f.1692916914.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index cfc2dc8..7c1ef5b 100644 (file)
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -629,19 +629,11 @@ static inline void io_cq_lock(struct io_ring_ctx *ctx)
 static inline void __io_cq_unlock_post(struct io_ring_ctx *ctx)
 {
        io_commit_cqring(ctx);
-
-       if (ctx->task_complete) {
-               /*
-                * ->task_complete implies that only current might be waiting
-                * for CQEs, and obviously, we currently don't. No one is
-                * waiting, wakeups are futile, skip them.
-                */
-               io_commit_cqring_flush(ctx);
-       } else {
+       if (!ctx->task_complete) {
                spin_unlock(&ctx->completion_lock);
-               io_commit_cqring_flush(ctx);
                io_cqring_wake(ctx);
        }
+       io_commit_cqring_flush(ctx);
 }
 
 static void io_cq_unlock_post(struct io_ring_ctx *ctx)
@@ -649,8 +641,8 @@ static void io_cq_unlock_post(struct io_ring_ctx *ctx)
 {
        io_commit_cqring(ctx);
        spin_unlock(&ctx->completion_lock);
-       io_commit_cqring_flush(ctx);
        io_cqring_wake(ctx);
+       io_commit_cqring_flush(ctx);
 }
 
 /* Returns true if there are no backlogged entries after the flush */

diff --git a/io_uring/rw.c b/io_uring/rw.c
index 9b51afd..20140d3 100644 (file)
--- a/io_uring/rw.c
+++ b/io_uring/rw.c
@@ -985,9 +985,9 @@ copy_iov:
 
 static void io_cqring_ev_posted_iopoll(struct io_ring_ctx *ctx)
 {
-       io_commit_cqring_flush(ctx);
        if (ctx->flags & IORING_SETUP_SQPOLL)
                io_cqring_wake(ctx);
+       io_commit_cqring_flush(ctx);
 }
 
 void io_rw_fail(struct io_kiocb *req)