PM / hibernate / memory hotplug: Rework mutual exclusion

Since all of the memory hotplug operations have to be carried out
under device_hotplug_lock, they won't need to acquire pm_mutex if
device_hotplug_lock is held around hibernation.

For this reason, make the hibernation code acquire
device_hotplug_lock after freezing user space processes and
release it before thawing them.  At the same tim drop the
lock_system_sleep() and unlock_system_sleep() calls from
lock_memory_hotplug() and unlock_memory_hotplug(), respectively.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Toshi Kani <toshi.kani@hp.com>

1 files changed, 0 insertions, 4 deletions

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index ca1dd3aa5eee..53ad1325d7a7 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -51,14 +51,10 @@ DEFINE_MUTEX(mem_hotplug_mutex);
 void lock_memory_hotplug(void)
 {
         mutex_lock(&mem_hotplug_mutex);
-
-        /* for exclusive hibernation if CONFIG_HIBERNATION=y */
-        lock_system_sleep();
 }
 
 void unlock_memory_hotplug(void)
 {
-        unlock_system_sleep();
         mutex_unlock(&mem_hotplug_mutex);
 }