From: Ulrich Obergfell <uobergfe@redhat.com>
Date: Fri, 6 Nov 2015 02:44:53 +0000 (-0800)
Subject: kernel/watchdog.c: remove {get|put}_online_cpus() from watchdog_{park|unpark}_threads()
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=a2a45b85ec45db4b041ea5d93b21033dbc3cc0fc;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git

kernel/watchdog.c: remove {get|put}_online_cpus() from watchdog_{park|unpark}_threads()

watchdog_{park|unpark}_threads() are now called in code paths that protect
themselves against CPU hotplug, so {get|put}_online_cpus() calls are
redundant and can be removed.

Signed-off-by: Ulrich Obergfell <uobergfe@redhat.com>
Acked-by: Don Zickus <dzickus@redhat.com>
Reviewed-by: Aaron Tomlin <atomlin@redhat.com>
Cc: Ulrich Obergfell <uobergfe@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index 13fdda1a4c91..84c4744d1977 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -683,33 +683,35 @@ static struct smp_hotplug_thread watchdog_threads = {
  * be parked and the watchdog threads of other CPUs can still be runnable.
  * Callers are expected to handle this special condition as appropriate in
  * their context.
+ *
+ * This function may only be called in a context that is protected against
+ * races with CPU hotplug - for example, via get_online_cpus().
  */
 static int watchdog_park_threads(void)
 {
 	int cpu, ret = 0;
 
-	get_online_cpus();
 	for_each_watchdog_cpu(cpu) {
 		ret = kthread_park(per_cpu(softlockup_watchdog, cpu));
 		if (ret)
 			break;
 	}
-	put_online_cpus();
 
 	return ret;
 }
 
 /*
  * unpark all watchdog threads that are specified in 'watchdog_cpumask'
+ *
+ * This function may only be called in a context that is protected against
+ * races with CPU hotplug - for example, via get_online_cpus().
  */
 static void watchdog_unpark_threads(void)
 {
 	int cpu;
 
-	get_online_cpus();
 	for_each_watchdog_cpu(cpu)
 		kthread_unpark(per_cpu(softlockup_watchdog, cpu));
-	put_online_cpus();
 }
 
 /*