From dc6ce4bc2b355a47f225a0205046b3ebf29a7f72 Mon Sep 17 00:00:00 2001 From: Jackie Liu Date: Thu, 16 May 2019 11:46:30 +0800 Subject: [PATCH] io_uring: adjust smp_rmb inside io_cqring_events Whenever smp_rmb is required to use io_cqring_events, keep smp_rmb inside the function io_cqring_events. Signed-off-by: Jackie Liu Signed-off-by: Jens Axboe --- fs/io_uring.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 67d1aae349d7..9cc7a101ef2a 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -2167,6 +2167,8 @@ static int io_ring_submit(struct io_ring_ctx *ctx, unsigned int to_submit) static unsigned io_cqring_events(struct io_cq_ring *ring) { + /* See comment at the top of this file */ + smp_rmb(); return READ_ONCE(ring->r.tail) - READ_ONCE(ring->r.head); } @@ -2182,8 +2184,6 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events, DEFINE_WAIT(wait); int ret; - /* See comment at the top of this file */ - smp_rmb(); if (io_cqring_events(ring) >= min_events) return 0; @@ -2205,8 +2205,6 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events, prepare_to_wait(&ctx->wait, &wait, TASK_INTERRUPTIBLE); ret = 0; - /* See comment at the top of this file */ - smp_rmb(); if (io_cqring_events(ring) >= min_events) break;