From b0a7a1db59a94ea1d8a55336d01e37da5ec28b5d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Stefan=20B=C3=BChler?= <source@stbuehler.de>
Date: Thu, 15 Apr 2021 17:30:58 +0800
Subject: [PATCH] io_uring: remove unnecessary barrier before reading SQ tail
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mainline inclusion
from mainline-5.1
commit 82ab082c0e2f8592c2ff6b2ab99a92d8406c8c2c
category: feature
bugzilla: https://bugzilla.openeuler.org/show_bug.cgi?id=27
CVE: NA
---------------------------

There is no operation before to order with.

Signed-off-by: Stefan Bühler <source@stbuehler.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: yangerkun <yangerkun@huawei.com>
Reviewed-by: zhangyi (F) <yi.zhang@huawei.com>
Signed-off-by: Cheng Jian <cj.chengjian@huawei.com>
---
 fs/io_uring.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 8e143aed7365..ba3fb2d8ec27 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1828,8 +1828,6 @@ 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;
-- 
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