Add suspend-related notifications for CPU hotplug

Since nonboot CPUs are now disabled after tasks and devices have been
frozen and the CPU hotplug infrastructure is used for this purpose, we need
special CPU hotplug notifications that will help the CPU-hotplug-aware
subsystems distinguish normal CPU hotplug events from CPU hotplug events
related to a system-wide suspend or resume operation in progress.  This
patch introduces such notifications and causes them to be used during
suspend and resume transitions.  It also changes all of the
CPU-hotplug-aware subsystems to take these notifications into consideration
(for now they are handled in the same way as the corresponding "normal"
ones).

[oleg@tv-sign.ru: cleanups]
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Gautham R Shenoy <ego@in.ibm.com>
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 0 deletions

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index b976ed8..fb56fed 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -799,6 +799,8 @@ static int __devinit workqueue_cpu_callback(struct notifier_block *nfb,
 	struct cpu_workqueue_struct *cwq;
 	struct workqueue_struct *wq;
 
+	action &= ~CPU_TASKS_FROZEN;
+
 	switch (action) {
 	case CPU_LOCK_ACQUIRE:
 		mutex_lock(&workqueue_mutex);