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, 4 insertions, 0 deletions

diff --git a/kernel/softlockup.c b/kernel/softlockup.c
index 8fa7040247ad..0131e296ffb4 100644
--- a/kernel/softlockup.c
+++ b/kernel/softlockup.c
@@ -146,6 +146,7 @@ cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu)
 
         switch (action) {
         case CPU_UP_PREPARE:
+        case CPU_UP_PREPARE_FROZEN:
                 BUG_ON(per_cpu(watchdog_task, hotcpu));
                 p = kthread_create(watchdog, hcpu, "watchdog/%d", hotcpu);
                 if (IS_ERR(p)) {
@@ -157,16 +158,19 @@ cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu)
                 kthread_bind(p, hotcpu);
                 break;
         case CPU_ONLINE:
+        case CPU_ONLINE_FROZEN:
                 wake_up_process(per_cpu(watchdog_task, hotcpu));
                 break;
 #ifdef CONFIG_HOTPLUG_CPU
         case CPU_UP_CANCELED:
+        case CPU_UP_CANCELED_FROZEN:
                 if (!per_cpu(watchdog_task, hotcpu))
                         break;
                 /* Unbind so it can run.  Fall thru. */
                 kthread_bind(per_cpu(watchdog_task, hotcpu),
                              any_online_cpu(cpu_online_map));
         case CPU_DEAD:
+        case CPU_DEAD_FROZEN:
                 p = per_cpu(watchdog_task, hotcpu);
                 per_cpu(watchdog_task, hotcpu) = NULL;
                 kthread_stop(p);