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>
diff --git a/Documentation/power/notifiers.txt b/Documentation/power/notifiers.txt
new file mode 100644
index 0000000..9293e4b
--- /dev/null
+++ b/Documentation/power/notifiers.txt
@@ -0,0 +1,50 @@
+Suspend notifiers
+ (C) 2007 Rafael J. Wysocki <rjw@sisk.pl>, GPL
+
+There are some operations that device drivers may want to carry out in their
+.suspend() routines, but shouldn't, because they can cause the hibernation or
+suspend to fail. For example, a driver may want to allocate a substantial amount
+of memory (like 50 MB) in .suspend(), but that shouldn't be done after the
+swsusp's memory shrinker has run.
+
+Also, there may be some operations, that subsystems want to carry out before a
+hibernation/suspend or after a restore/resume, requiring the system to be fully
+functional, so the drivers' .suspend() and .resume() routines are not suitable
+for this purpose. For example, device drivers may want to upload firmware to
+their devices after a restore from a hibernation image, but they cannot do it by
+calling request_firmware() from their .resume() routines (user land processes
+are frozen at this point). The solution may be to load the firmware into
+memory before processes are frozen and upload it from there in the .resume()
+routine. Of course, a hibernation notifier may be used for this purpose.
+
+The subsystems that have such needs can register suspend notifiers that will be
+called upon the following events by the suspend core:
+
+PM_HIBERNATION_PREPARE The system is going to hibernate or suspend, tasks will
+ be frozen immediately.
+
+PM_POST_HIBERNATION The system memory state has been restored from a
+ hibernation image or an error occured during the
+ hibernation. Device drivers' .resume() callbacks have
+ been executed and tasks have been thawed.
+
+PM_SUSPEND_PREPARE The system is preparing for a suspend.
+
+PM_POST_SUSPEND The system has just resumed or an error occured during
+ the suspend. Device drivers' .resume() callbacks have
+ been executed and tasks have been thawed.
+
+It is generally assumed that whatever the notifiers do for
+PM_HIBERNATION_PREPARE, should be undone for PM_POST_HIBERNATION. Analogously,
+operations performed for PM_SUSPEND_PREPARE should be reversed for
+PM_POST_SUSPEND. Additionally, all of the notifiers are called for
+PM_POST_HIBERNATION if one of them fails for PM_HIBERNATION_PREPARE, and
+all of the notifiers are called for PM_POST_SUSPEND if one of them fails for
+PM_SUSPEND_PREPARE.
+
+The hibernation and suspend notifiers are called with pm_mutex held. They are
+defined in the usual way, but their last argument is meaningless (it is always
+NULL). To register and/or unregister a suspend notifier use the functions
+register_pm_notifier() and unregister_pm_notifier(), respectively, defined in
+include/linux/suspend.h . If you don't need to unregister the notifier, you can
+also use the pm_notifier() macro defined in include/linux/suspend.h .
diff --git a/include/linux/notifier.h b/include/linux/notifier.h
index 576f2bb..be3f2bb 100644
--- a/include/linux/notifier.h
+++ b/include/linux/notifier.h
@@ -212,5 +212,11 @@
#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 d235c14..e8e6da3 100644
--- a/include/linux/suspend.h
+++ b/include/linux/suspend.h
@@ -54,7 +54,8 @@
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 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 @@
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 */
diff --git a/kernel/power/disk.c b/kernel/power/disk.c
index 885c653..324ac01 100644
--- a/kernel/power/disk.c
+++ b/kernel/power/disk.c
@@ -281,9 +281,16 @@
{
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 @@
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 @@
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;
}
diff --git a/kernel/power/main.c b/kernel/power/main.c
index fc45ed2..4d26ad3 100644
--- a/kernel/power/main.c
+++ b/kernel/power/main.c
@@ -23,6 +23,8 @@
#include "power.h"
+BLOCKING_NOTIFIER_HEAD(pm_chain_head);
+
/*This is just an arbitrary number */
#define FREE_PAGE_NUMBER (100)
@@ -78,6 +80,10 @@
if (!pm_ops || !pm_ops->enter)
return -EPERM;
+ error = pm_notifier_call_chain(PM_SUSPEND_PREPARE);
+ if (error)
+ goto Finish;
+
pm_prepare_console();
if (freeze_processes()) {
@@ -125,6 +131,8 @@
Thaw:
thaw_processes();
pm_restore_console();
+ Finish:
+ pm_notifier_call_chain(PM_POST_SUSPEND);
return error;
}
@@ -176,6 +184,7 @@
resume_console();
thaw_processes();
pm_restore_console();
+ pm_notifier_call_chain(PM_POST_SUSPEND);
}
diff --git a/kernel/power/power.h b/kernel/power/power.h
index eab3603..01c2275 100644
--- a/kernel/power/power.h
+++ b/kernel/power/power.h
@@ -173,5 +173,15 @@
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;
+}
diff --git a/kernel/power/user.c b/kernel/power/user.c
index 1f24f30..7f19afe 100644
--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -151,10 +151,14 @@
if (data->frozen)
break;
mutex_lock(&pm_mutex);
- if (freeze_processes()) {
- thaw_processes();
- error = -EBUSY;
+ error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
+ if (!error) {
+ error = freeze_processes();
+ if (error)
+ thaw_processes();
}
+ if (error)
+ pm_notifier_call_chain(PM_POST_HIBERNATION);
mutex_unlock(&pm_mutex);
if (!error)
data->frozen = 1;
@@ -165,6 +169,7 @@
break;
mutex_lock(&pm_mutex);
thaw_processes();
+ pm_notifier_call_chain(PM_POST_HIBERNATION);
mutex_unlock(&pm_mutex);
data->frozen = 0;
break;