From: "Paul E. McKenney" <paulmck@kernel.org>
Date: Tue, 31 Jan 2023 16:12:18 -0800
Subject: [PATCH] refscale: Move shutdown from wait_event() to
 wait_event_idle()
References: bsc#1012628
Patch-mainline: 6.3.4
Git-commit: 6bc6e6b27524304aadb9c04611ddb1c84dd7617a

[ Upstream commit 6bc6e6b27524304aadb9c04611ddb1c84dd7617a ]

The ref_scale_shutdown() kthread/function uses wait_event() to wait for
the refscale test to complete.  However, although the read-side tests
are normally extremely fast, there is no law against specifying a very
large value for the refscale.loops module parameter or against having
a slow read-side primitive.  Either way, this might well trigger the
hung-task timeout.

This commit therefore replaces those wait_event() calls with calls to
wait_event_idle(), which do not trigger the hung-task timeout.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 kernel/rcu/refscale.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/rcu/refscale.c b/kernel/rcu/refscale.c
index afa3e1a2..1970ce5f 100644
--- a/kernel/rcu/refscale.c
+++ b/kernel/rcu/refscale.c
@@ -1031,7 +1031,7 @@ ref_scale_cleanup(void)
 static int
 ref_scale_shutdown(void *arg)
 {
-	wait_event(shutdown_wq, shutdown_start);
+	wait_event_idle(shutdown_wq, shutdown_start);
 
 	smp_mb(); // Wake before output.
 	ref_scale_cleanup();
-- 
2.35.3