From: Stefan Bühler <source@stbuehler.de>
Date: Wed, 24 Apr 2019 21:54:20 +0000 (+0200)
Subject: io_uring: remove unnecessary barrier before reading SQ tail
X-Git-Tag: v5.1~12^2~9
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=82ab082c0e2f8592c2ff6b2ab99a92d8406c8c2c;p=linux.git

io_uring: remove unnecessary barrier before reading SQ tail

There is no operation before to order with.

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 d3c57ee233fe..662f1c070c8c 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1831,8 +1831,6 @@ static bool io_get_sqring(struct io_ring_ctx *ctx, struct sqe_submit *s)
 	 *    though the application is the one updating it.
 	 */
 	head = ctx->cached_sq_head;
-	/* See comment at the top of this file */
-	smp_rmb();
 	/* make sure SQ entry isn't read before tail */
 	if (head == smp_load_acquire(&ring->r.tail))
 		return false;