Merge branch 'next' into for-linus

1 files changed, 32 insertions, 18 deletions

diff --git a/include/linux/suspend.h b/include/linux/suspend.h
index 57a692432f8..91784a4f860 100644
--- a/include/linux/suspend.h
+++ b/include/linux/suspend.h
@@ -6,6 +6,7 @@
 #include <linux/init.h>
 #include <linux/pm.h>
 #include <linux/mm.h>
+#include <linux/freezer.h>
 #include <asm/errno.h>
 
 #ifdef CONFIG_VT
@@ -331,6 +332,8 @@ static inline bool system_entering_hibernation(void) { return false; }
 #define PM_RESTORE_PREPARE	0x0005 /* Going to restore a saved image */
 #define PM_POST_RESTORE		0x0006 /* Restore failed */
 
+extern struct mutex pm_mutex;
+
 #ifdef CONFIG_PM_SLEEP
 void save_processor_state(void);
 void restore_processor_state(void);
@@ -351,6 +354,34 @@ extern bool events_check_enabled;
 extern bool pm_wakeup_pending(void);
 extern bool pm_get_wakeup_count(unsigned int *count);
 extern bool pm_save_wakeup_count(unsigned int count);
+
+static inline void lock_system_sleep(void)
+{
+	current->flags |= PF_FREEZER_SKIP;
+	mutex_lock(&pm_mutex);
+}
+
+static inline void unlock_system_sleep(void)
+{
+	/*
+	 * Don't use freezer_count() because we don't want the call to
+	 * try_to_freeze() here.
+	 *
+	 * Reason:
+	 * Fundamentally, we just don't need it, because freezing condition
+	 * doesn't come into effect until we release the pm_mutex lock,
+	 * since the freezer always works with pm_mutex held.
+	 *
+	 * More importantly, in the case of hibernation,
+	 * unlock_system_sleep() gets called in snapshot_read() and
+	 * snapshot_write() when the freezing condition is still in effect.
+	 * Which means, if we use try_to_freeze() here, it would make them
+	 * enter the refrigerator, thus causing hibernation to lockup.
+	 */
+	current->flags &= ~PF_FREEZER_SKIP;
+	mutex_unlock(&pm_mutex);
+}
+
 #else /* !CONFIG_PM_SLEEP */
 
 static inline int register_pm_notifier(struct notifier_block *nb)
@@ -366,28 +397,11 @@ static inline int unregister_pm_notifier(struct notifier_block *nb)
 #define pm_notifier(fn, pri)	do { (void)(fn); } while (0)
 
 static inline bool pm_wakeup_pending(void) { return false; }
-#endif /* !CONFIG_PM_SLEEP */
-
-extern struct mutex pm_mutex;
 
-#ifndef CONFIG_HIBERNATE_CALLBACKS
 static inline void lock_system_sleep(void) {}
 static inline void unlock_system_sleep(void) {}
 
-#else
-
-/* Let some subsystems like memory hotadd exclude hibernation */
-
-static inline void lock_system_sleep(void)
-{
-	mutex_lock(&pm_mutex);
-}
-
-static inline void unlock_system_sleep(void)
-{
-	mutex_unlock(&pm_mutex);
-}
-#endif
+#endif /* !CONFIG_PM_SLEEP */
 
 #ifdef CONFIG_ARCH_SAVE_PAGE_KEYS
 /*