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>

4 files changed, 39 insertions, 7 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;
 }
 
diff --git a/kernel/power/main.c b/kernel/power/main.c
index fc45ed22620f..4d26ad394fb3 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 @@ static int suspend_prepare(suspend_state_t state)
         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 @@ static int suspend_prepare(suspend_state_t state)
  Thaw:
         thaw_processes();
         pm_restore_console();
+ Finish:
+        pm_notifier_call_chain(PM_POST_SUSPEND);
         return error;
 }
 
@@ -176,6 +184,7 @@ static void suspend_finish(suspend_state_t state)
         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 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;
+}
diff --git a/kernel/power/user.c b/kernel/power/user.c
index 1f24f30b951b..7f19afe01b48 100644
--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -151,10 +151,14 @@ static int snapshot_ioctl(struct inode *inode, struct file *filp,
                 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 @@ static int snapshot_ioctl(struct inode *inode, struct file *filp,
                         break;
                 mutex_lock(&pm_mutex);
                 thaw_processes();
+                pm_notifier_call_chain(PM_POST_HIBERNATION);
                 mutex_unlock(&pm_mutex);
                 data->frozen = 0;
                 break;