To prevent race conditions on userspace processes with I/O some taks must be
called after processes are freezed. This patch adds new events which are
delivered by pm_notifier_call_chain() after freezing processes when doing
suspend or hibernate action.

Signed-off-by: Pali Rohár <[email protected]>
---
 include/linux/suspend.h  |    2 ++
 kernel/power/hibernate.c |    2 ++
 kernel/power/suspend.c   |    4 +++-
 3 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/include/linux/suspend.h b/include/linux/suspend.h
index 5efe743..bc743c8 100644
--- a/include/linux/suspend.h
+++ b/include/linux/suspend.h
@@ -368,6 +368,8 @@ static inline bool hibernation_available(void) { return 
false; }
 #define PM_POST_SUSPEND                0x0004 /* Suspend finished */
 #define PM_RESTORE_PREPARE     0x0005 /* Going to restore a saved image */
 #define PM_POST_RESTORE                0x0006 /* Restore failed */
+#define PM_HIBERNATION_AFTER_FREEZE    0x0007 /* After hibernation freeze */
+#define PM_SUSPEND_AFTER_FREEZE                0x0008 /* After suspend freeze 
*/
 
 extern struct mutex pm_mutex;
 
diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index 2329daa..184f7ee 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -671,6 +671,8 @@ int hibernate(void)
        if (error)
                goto Exit;
 
+       pm_notifier_call_chain(PM_HIBERNATION_AFTER_FREEZE);
+
        lock_device_hotplug();
        /* Allocate memory management structures */
        error = create_basic_memory_bitmaps();
diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
index 8d7a1ef..ba2a945 100644
--- a/kernel/power/suspend.c
+++ b/kernel/power/suspend.c
@@ -277,8 +277,10 @@ static int suspend_prepare(suspend_state_t state)
        trace_suspend_resume(TPS("freeze_processes"), 0, true);
        error = suspend_freeze_processes();
        trace_suspend_resume(TPS("freeze_processes"), 0, false);
-       if (!error)
+       if (!error) {
+               pm_notifier_call_chain(PM_SUSPEND_AFTER_FREEZE);
                return 0;
+       }
 
        suspend_stats.failed_freeze++;
        dpm_save_failed_step(SUSPEND_FREEZE);
-- 
1.7.9.5

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