PM: introduce hibernation and suspend notifiers

Make it possible to register hibernation and suspend notifiers, so that
subsystems can perform hibernation-related or suspend-related operations that
should not be carried out by device drivers' .suspend() and .resume()
routines.

[akpm@linux-foundation.org: build fixes]
[akpm@linux-foundation.org: cleanups]
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Cc: Nigel Cunningham <nigel@nigel.suspend2.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 12 insertions, 4 deletions

diff --git a/kernel/power/disk.c b/kernel/power/disk.c
index 885c653509c9..324ac0188ce1 100644
--- a/kernel/power/disk.c
+++ b/kernel/power/disk.c
@@ -281,9 +281,16 @@ int hibernate(void)
 {
         int error;
 
+        mutex_lock(&pm_mutex);
         /* The snapshot device should not be opened while we're running */
-        if (!atomic_add_unless(&snapshot_device_available, -1, 0))
-                return -EBUSY;
+        if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
+                error = -EBUSY;
+                goto Unlock;
+        }
+
+        error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
+        if (error)
+                goto Exit;
 
         /* Allocate memory management structures */
         error = create_basic_memory_bitmaps();
@@ -294,7 +301,6 @@ int hibernate(void)
         if (error)
                 goto Finish;
 
-        mutex_lock(&pm_mutex);
         if (hibernation_mode == HIBERNATION_TESTPROC) {
                 printk("swsusp debug: Waiting for 5 seconds.\n");
                 mdelay(5000);
@@ -316,12 +322,14 @@ int hibernate(void)
                 swsusp_free();
         }
  Thaw:
-        mutex_unlock(&pm_mutex);
         unprepare_processes();
  Finish:
         free_basic_memory_bitmaps();
  Exit:
+        pm_notifier_call_chain(PM_POST_HIBERNATION);
         atomic_inc(&snapshot_device_available);
+ Unlock:
+        mutex_unlock(&pm_mutex);
         return error;
 }