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>
diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index d4e5405..0b78f72 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -652,6 +652,7 @@
if (error)
goto Exit;
+ lock_device_hotplug();
/* Allocate memory management structures */
error = create_basic_memory_bitmaps();
if (error)
@@ -685,6 +686,7 @@
Free_bitmaps:
free_basic_memory_bitmaps();
Thaw:
+ unlock_device_hotplug();
thaw_processes();
/* Don't bother checking whether freezer_test_done is true */
@@ -814,6 +816,7 @@
pr_debug("PM: Loading hibernation image.\n");
+ lock_device_hotplug();
error = create_basic_memory_bitmaps();
if (error)
goto Thaw;
@@ -827,6 +830,7 @@
swsusp_free();
free_basic_memory_bitmaps();
Thaw:
+ unlock_device_hotplug();
thaw_processes();
Finish:
pm_notifier_call_chain(PM_POST_RESTORE);