linux-kernel - [PATCH] sched/core: Use do-while instead of for loop in set_nr_if

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Message-Id: <20230228161426.4508-1-ubizjak@gmail.com>
Date:   Tue, 28 Feb 2023 17:14:26 +0100
From:   Uros Bizjak <ubizjak@...il.com>
To:     linux-kernel@...r.kernel.org
Cc:     Uros Bizjak <ubizjak@...il.com>, Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Juri Lelli <juri.lelli@...hat.com>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Dietmar Eggemann <dietmar.eggemann@....com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Ben Segall <bsegall@...gle.com>, Mel Gorman <mgorman@...e.de>,
        Daniel Bristot de Oliveira <bristot@...hat.com>,
        Christian Brauner <brauner@...nel.org>
Subject: [PATCH] sched/core: Use do-while instead of for loop in set_nr_if_polling

Use equivalent do-while loop instead of infinite for loop.

There are no asm code changes.

Signed-off-by: Uros Bizjak <ubizjak@...il.com>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Juri Lelli <juri.lelli@...hat.com>
Cc: Vincent Guittot <vincent.guittot@...aro.org>
Cc: Dietmar Eggemann <dietmar.eggemann@....com>
Cc: Steven Rostedt <rostedt@...dmis.org>
Cc: Ben Segall <bsegall@...gle.com>
Cc: Mel Gorman <mgorman@...e.de>
Cc: Daniel Bristot de Oliveira <bristot@...hat.com>
Cc: Christian Brauner <brauner@...nel.org>
---
 kernel/sched/core.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index af017e038b48..349c018eaf09 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -899,14 +899,13 @@ static bool set_nr_if_polling(struct task_struct *p)
 	struct thread_info *ti = task_thread_info(p);
 	typeof(ti->flags) val = READ_ONCE(ti->flags);
 
-	for (;;) {
+	do {
 		if (!(val & _TIF_POLLING_NRFLAG))
 			return false;
 		if (val & _TIF_NEED_RESCHED)
 			return true;
-		if (try_cmpxchg(&ti->flags, &val, val | _TIF_NEED_RESCHED))
-			break;
-	}
+	} while (!try_cmpxchg(&ti->flags, &val, val | _TIF_NEED_RESCHED));
+
 	return true;
 }
 
-- 
2.39.2