io_uring: refactor io_cqring_wake()

Instead of smp_mb() + __io_cqring_wake() in __io_cq_unlock_post_flush()
use equivalent io_cqring_wake(). With that we can clean it up further
and remove __io_cqring_wake().

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/662ee5d898168ac206be06038525e97b64072a46.1680782017.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 fb7215b543cddcfb2bffb4c8671903775a36e05a..d4ac62de2113f140ca6082d6821af1e631136404 100644 (file)
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -640,10 +640,8 @@ static inline void __io_cq_unlock_post_flush(struct io_ring_ctx *ctx)
         * it will re-check the wakeup conditions once we return we can safely
         * skip waking it up.
         */
-       if (!(ctx->flags & IORING_SETUP_DEFER_TASKRUN)) {
-               smp_mb();
-               __io_cqring_wake(ctx);
-       }
+       if (!(ctx->flags & IORING_SETUP_DEFER_TASKRUN))
+               io_cqring_wake(ctx);
 }
 
 void io_cq_unlock_post(struct io_ring_ctx *ctx)

diff --git a/io_uring/io_uring.h b/io_uring/io_uring.h
index 193b2db39fe8ac6f9cffe44ffd16e8b18b960351..24d8196bbca3cf97d77d636eef41747f5514eab2 100644 (file)
--- a/io_uring/io_uring.h
+++ b/io_uring/io_uring.h
@@ -228,8 +228,7 @@ static inline void io_poll_wq_wake(struct io_ring_ctx *ctx)
                                poll_to_key(EPOLL_URING_WAKE | EPOLLIN));
 }
 
-/* requires smb_mb() prior, see wq_has_sleeper() */
-static inline void __io_cqring_wake(struct io_ring_ctx *ctx)
+static inline void io_cqring_wake(struct io_ring_ctx *ctx)
 {
        /*
         * Trigger waitqueue handler on all waiters on our waitqueue. This
@@ -241,17 +240,11 @@ static inline void __io_cqring_wake(struct io_ring_ctx *ctx)
         * waitqueue handlers, we know we have a dependency between eventfd or
         * epoll and should terminate multishot poll at that point.
         */
-       if (waitqueue_active(&ctx->cq_wait))
+       if (wq_has_sleeper(&ctx->cq_wait))
                __wake_up(&ctx->cq_wait, TASK_NORMAL, 0,
                                poll_to_key(EPOLL_URING_WAKE | EPOLLIN));
 }
 
-static inline void io_cqring_wake(struct io_ring_ctx *ctx)
-{
-       smp_mb();
-       __io_cqring_wake(ctx);
-}
-
 static inline bool io_sqring_full(struct io_ring_ctx *ctx)
 {
        struct io_rings *r = ctx->rings;