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authorUlrich Obergfell <uobergfe@redhat.com>2015-11-05 18:44:53 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2015-11-05 19:34:48 -0800
commita2a45b85ec45db4b041ea5d93b21033dbc3cc0fc (patch)
treedc9ae8545451962f41fd518194b29977080e3842
parent8614ddef82139d08234dbf681188f9bcddae9f03 (diff)
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>
-rw-r--r--kernel/watchdog.c10
1 files changed, 6 insertions, 4 deletions
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();
}
/*