From cc42d13aa8f3bf2e898935f147e67a040bc20c7d Mon Sep 17 00:00:00 2001
From: Jens Axboe <axboe@kernel.dk>
Date: Thu, 19 Sep 2019 09:48:55 -0600
Subject: [PATCH] io_uring: use cond_resched() in sqthread

commit 9831a90ce64362f8429e8fd23838a9db2cdf7803 upstream.

If preempt isn't enabled in the kernel, we can run into hang issues with
sqthread submissions. Use cond_resched() to play nice instead of
cpu_relax(), if we end up starting the loop and not having any events
pending for submissions.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
---
 fs/io_uring.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 325f27533672..407b69d85d4a 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2437,7 +2437,7 @@ static int io_sq_thread(void *data)
 			 * to sleep.
 			 */
 			if (inflight || !time_after(jiffies, timeout)) {
-				cpu_relax();
+				cond_resched();
 				continue;
 			}
 
-- 
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