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/relay.c b/kernel/relay.c
index e804589c863c..61a504900eaa 100644
--- a/kernel/relay.c
+++ b/kernel/relay.c
@@ -484,6 +484,7 @@ static int __cpuinit relay_hotcpu_callback(struct notifier_block *nb,
 
         switch(action) {
         case CPU_UP_PREPARE:
+        case CPU_UP_PREPARE_FROZEN:
                 mutex_lock(&relay_channels_mutex);
                 list_for_each_entry(chan, &relay_channels, list) {
                         if (chan->buf[hotcpu])
@@ -500,6 +501,7 @@ static int __cpuinit relay_hotcpu_callback(struct notifier_block *nb,
                 mutex_unlock(&relay_channels_mutex);
                 break;
         case CPU_DEAD:
+        case CPU_DEAD_FROZEN:
                 /* No need to flush the cpu : will be flushed upon
                  * final relay_flush() call. */
                 break;