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, 10 insertions, 0 deletions

diff --git a/kernel/power/power.h b/kernel/power/power.h
index eab3603b7caf..01c2275b15b2 100644
--- a/kernel/power/power.h
+++ b/kernel/power/power.h
@@ -173,5 +173,15 @@ extern void swsusp_close(void);
 extern int suspend_enter(suspend_state_t state);
 
 struct timeval;
+/* kernel/power/swsusp.c */
 extern void swsusp_show_speed(struct timeval *, struct timeval *,
                                 unsigned int, char *);
+
+/* kernel/power/main.c */
+extern struct blocking_notifier_head pm_chain_head;
+
+static inline int pm_notifier_call_chain(unsigned long val)
+{
+        return (blocking_notifier_call_chain(&pm_chain_head, val, NULL)
+                        == NOTIFY_BAD) ? -EINVAL : 0;
+}