From: Ulrich Obergfell 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-Tag: firefly_0821_release~176^2~776^2~137 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=a2a45b85ec45db4b041ea5d93b21033dbc3cc0fc;p=firefly-linux-kernel-4.4.55.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 Acked-by: Don Zickus Reviewed-by: Aaron Tomlin Cc: Ulrich Obergfell Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- 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(); } /*