io_uring: remove unnecessary barrier after unsetting IORING_SQ_NEED_WAKEUP

There is no operation to order with afterwards, and removing the flag is
not critical in any way.

There will always be a "race condition" where the application will
trigger IORING_ENTER_SQ_WAKEUP when it isn't actually needed.

Signed-off-by: Stefan Bühler <source@stbuehler.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 2ebc33c..77b247b 100644 (file)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1969,13 +1969,11 @@ static int io_sq_thread(void *data)
                                finish_wait(&ctx->sqo_wait, &wait);
 
                                ctx->sq_ring->flags &= ~IORING_SQ_NEED_WAKEUP;
-                               smp_wmb();
                                continue;
                        }
                        finish_wait(&ctx->sqo_wait, &wait);
 
                        ctx->sq_ring->flags &= ~IORING_SQ_NEED_WAKEUP;
-                       smp_wmb();
                }
 
                i = 0;