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>

2 files changed, 49 insertions, 5 deletions

diff --git a/include/linux/notifier.h b/include/linux/notifier.h
index 576f2bb34cc8..be3f2bb6fcf3 100644
--- a/include/linux/notifier.h
+++ b/include/linux/notifier.h
@@ -212,5 +212,11 @@ extern int __srcu_notifier_call_chain(struct srcu_notifier_head *nh,
 #define CPU_DEAD_FROZEN         (CPU_DEAD | CPU_TASKS_FROZEN)
 #define CPU_DYING_FROZEN        (CPU_DYING | CPU_TASKS_FROZEN)
 
+/* Hibernation and suspend events */
+#define PM_HIBERNATION_PREPARE  0x0001 /* Going to hibernate */
+#define PM_POST_HIBERNATION     0x0002 /* Hibernation finished */
+#define PM_SUSPEND_PREPARE      0x0003 /* Going to suspend the system */
+#define PM_POST_SUSPEND         0x0004 /* Suspend finished */
+
 #endif /* __KERNEL__ */
 #endif /* _LINUX_NOTIFIER_H */
diff --git a/include/linux/suspend.h b/include/linux/suspend.h
index d235c146da2b..e8e6da394c92 100644
--- a/include/linux/suspend.h
+++ b/include/linux/suspend.h
@@ -54,7 +54,8 @@ struct hibernation_ops {
         void (*restore_cleanup)(void);
 };
 
-#if defined(CONFIG_PM) && defined(CONFIG_SOFTWARE_SUSPEND)
+#ifdef CONFIG_PM
+#ifdef CONFIG_SOFTWARE_SUSPEND
 /* kernel/power/snapshot.c */
 extern void __register_nosave_region(unsigned long b, unsigned long e, int km);
 static inline void register_nosave_region(unsigned long b, unsigned long e)
@@ -72,16 +73,14 @@ extern unsigned long get_safe_page(gfp_t gfp_mask);
 
 extern void hibernation_set_ops(struct hibernation_ops *ops);
 extern int hibernate(void);
-#else
-static inline void register_nosave_region(unsigned long b, unsigned long e) {}
-static inline void register_nosave_region_late(unsigned long b, unsigned long e) {}
+#else /* CONFIG_SOFTWARE_SUSPEND */
 static inline int swsusp_page_is_forbidden(struct page *p) { return 0; }
 static inline void swsusp_set_page_free(struct page *p) {}
 static inline void swsusp_unset_page_free(struct page *p) {}
 
 static inline void hibernation_set_ops(struct hibernation_ops *ops) {}
 static inline int hibernate(void) { return -ENOSYS; }
-#endif /* defined(CONFIG_PM) && defined(CONFIG_SOFTWARE_SUSPEND) */
+#endif /* CONFIG_SOFTWARE_SUSPEND */
 
 void save_processor_state(void);
 void restore_processor_state(void);
@@ -89,4 +88,43 @@ struct saved_context;
 void __save_processor_state(struct saved_context *ctxt);
 void __restore_processor_state(struct saved_context *ctxt);
 
+/* kernel/power/main.c */
+extern struct blocking_notifier_head pm_chain_head;
+
+static inline int register_pm_notifier(struct notifier_block *nb)
+{
+        return blocking_notifier_chain_register(&pm_chain_head, nb);
+}
+
+static inline int unregister_pm_notifier(struct notifier_block *nb)
+{
+        return blocking_notifier_chain_unregister(&pm_chain_head, nb);
+}
+
+#define pm_notifier(fn, pri) {                          \
+        static struct notifier_block fn##_nb =                  \
+                { .notifier_call = fn, .priority = pri };       \
+        register_pm_notifier(&fn##_nb);                 \
+}
+#else /* CONFIG_PM */
+
+static inline int register_pm_notifier(struct notifier_block *nb)
+{
+        return 0;
+}
+
+static inline int unregister_pm_notifier(struct notifier_block *nb)
+{
+        return 0;
+}
+
+#define pm_notifier(fn, pri)    do { (void)(fn); } while (0)
+#endif /* CONFIG_PM */
+
+#if !defined CONFIG_SOFTWARE_SUSPEND || !defined(CONFIG_PM)
+static inline void register_nosave_region(unsigned long b, unsigned long e)
+{
+}
+#endif
+
 #endif /* _LINUX_SWSUSP_H */