Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/suspend-2.6

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/suspend-2.6:
  spi / PM: Support dev_pm_ops
  PM: Prototype the pm_generic_ operations
  PM / Runtime: Generic resume shouldn't set RPM_ACTIVE unconditionally
  PM: Use dev_name() in core device suspend and resume routines
  PM: Permit registration of parentless devices during system suspend
  PM: Replace the device power.status field with a bit field
  PM: Remove redundant checks from core device resume routines
  PM: Use a different list of devices for each stage of device suspend
  PM: Avoid compiler warning in pm_noirq_op()
  PM: Use pm_wakeup_pending() in __device_suspend()
  PM / Wakeup: Replace pm_check_wakeup_events() with pm_wakeup_pending()
  PM: Prevent dpm_prepare() from returning errors unnecessarily
  PM: Fix references to basic-pm-debugging.txt in drivers-testing.txt
  PM / Runtime: Add synchronous runtime interface for interrupt handlers (v3)
  PM / Hibernate: When failed, in_suspend should be reset
  PM / Hibernate: hibernation_ops->leave should be checked too
  Freezer: Fix a race during freezing of TASK_STOPPED tasks
  PM: Use proper ccflag flag in kernel/power/Makefile
  PM / Runtime: Fix comments to match runtime callback code

Documentation/power/drivers-testing.txt

@@ -23,10 +23,10 @@ Once you have resolved the suspend/resume-related problems with your test system
 without the new driver, you are ready to test it:
 
 a) Build the driver as a module, load it and try the test modes of hibernation
-   (see: Documents/power/basic-pm-debugging.txt, 1).
+   (see: Documentation/power/basic-pm-debugging.txt, 1).
 
 b) Load the driver and attempt to hibernate in the "reboot", "shutdown" and
-   "platform" modes (see: Documents/power/basic-pm-debugging.txt, 1).
+   "platform" modes (see: Documentation/power/basic-pm-debugging.txt, 1).
 
 c) Compile the driver directly into the kernel and try the test modes of
    hibernation.
@@ -34,12 +34,12 @@ c) Compile the driver directly into the kernel and try the test modes of
 d) Attempt to hibernate with the driver compiled directly into the kernel
    in the "reboot", "shutdown" and "platform" modes.
 
-e) Try the test modes of suspend (see: Documents/power/basic-pm-debugging.txt,
+e) Try the test modes of suspend (see: Documentation/power/basic-pm-debugging.txt,
    2).  [As far as the STR tests are concerned, it should not matter whether or
    not the driver is built as a module.]
 
 f) Attempt to suspend to RAM using the s2ram tool with the driver loaded
-   (see: Documents/power/basic-pm-debugging.txt, 2).
+   (see: Documentation/power/basic-pm-debugging.txt, 2).
 
 Each of the above tests should be repeated several times and the STD tests
 should be mixed with the STR tests.  If any of them fails, the driver cannot be

Documentation/power/runtime_pm.txt

@@ -50,6 +50,15 @@ type's callbacks are not defined) of given device.  The bus type, device type
 and device class callbacks are referred to as subsystem-level callbacks in what
 follows.
 
+By default, the callbacks are always invoked in process context with interrupts
+enabled.  However, subsystems can use the pm_runtime_irq_safe() helper function
+to tell the PM core that a device's ->runtime_suspend() and ->runtime_resume()
+callbacks should be invoked in atomic context with interrupts disabled
+(->runtime_idle() is still invoked the default way).  This implies that these
+callback routines must not block or sleep, but it also means that the
+synchronous helper functions listed at the end of Section 4 can be used within
+an interrupt handler or in an atomic context.
+
 The subsystem-level suspend callback is _entirely_ _responsible_ for handling
 the suspend of the device as appropriate, which may, but need not include
 executing the device driver's own ->runtime_suspend() callback (from the
@@ -237,6 +246,10 @@ defined in include/linux/pm.h:
       Section 8); it may be modified only by the pm_runtime_no_callbacks()
       helper function
 
+  unsigned int irq_safe;
+    - indicates that the ->runtime_suspend() and ->runtime_resume() callbacks
+      will be invoked with the spinlock held and interrupts disabled
+
   unsigned int use_autosuspend;
     - indicates that the device's driver supports delayed autosuspend (see
       Section 9); it may be modified only by the
@@ -344,6 +357,10 @@ drivers/base/power/runtime.c and include/linux/pm_runtime.h:
     - decrement the device's usage counter; if the result is 0 then run
       pm_runtime_idle(dev) and return its result
 
+  int pm_runtime_put_sync_suspend(struct device *dev);
+    - decrement the device's usage counter; if the result is 0 then run
+      pm_runtime_suspend(dev) and return its result
+
   int pm_runtime_put_sync_autosuspend(struct device *dev);
     - decrement the device's usage counter; if the result is 0 then run
       pm_runtime_autosuspend(dev) and return its result
@@ -397,6 +414,11 @@ drivers/base/power/runtime.c and include/linux/pm_runtime.h:
       PM attributes from /sys/devices/.../power (or prevent them from being
       added when the device is registered)
 
+  void pm_runtime_irq_safe(struct device *dev);
+    - set the power.irq_safe flag for the device, causing the runtime-PM
+      suspend and resume callbacks (but not the idle callback) to be invoked
+      with interrupts disabled
+
   void pm_runtime_mark_last_busy(struct device *dev);
     - set the power.last_busy field to the current time
 
@@ -438,6 +460,15 @@ pm_runtime_suspended()
 pm_runtime_mark_last_busy()
 pm_runtime_autosuspend_expiration()
 
+If pm_runtime_irq_safe() has been called for a device then the following helper
+functions may also be used in interrupt context:
+
+pm_runtime_suspend()
+pm_runtime_autosuspend()
+pm_runtime_resume()
+pm_runtime_get_sync()
+pm_runtime_put_sync_suspend()
+
 5. Run-time PM Initialization, Device Probing and Removal
 
 Initially, the run-time PM is disabled for all devices, which means that the

drivers/base/power/generic_ops.c

@@ -39,7 +39,7 @@ EXPORT_SYMBOL_GPL(pm_generic_runtime_idle);
  *
  * If PM operations are defined for the @dev's driver and they include
  * ->runtime_suspend(), execute it and return its error code.  Otherwise,
- * return -EINVAL.
+ * return 0.
  */
 int pm_generic_runtime_suspend(struct device *dev)
 {
@@ -58,7 +58,7 @@ EXPORT_SYMBOL_GPL(pm_generic_runtime_suspend);
  *
  * If PM operations are defined for the @dev's driver and they include
  * ->runtime_resume(), execute it and return its error code.  Otherwise,
- * return -EINVAL.
+ * return 0.
  */
 int pm_generic_runtime_resume(struct device *dev)
 {
@@ -185,7 +185,7 @@ static int __pm_generic_resume(struct device *dev, int event)
 		return 0;
 
 	ret = callback(dev);
-	if (!ret) {
+	if (!ret && pm_runtime_enabled(dev)) {
 		pm_runtime_disable(dev);
 		pm_runtime_set_active(dev);
 		pm_runtime_enable(dev);

drivers/base/power/runtime.c

@@ -250,13 +250,16 @@ static int rpm_callback(int (*cb)(struct device *), struct device *dev)
 	if (!cb)
 		return -ENOSYS;
 
+	if (dev->power.irq_safe) {
+		retval = cb(dev);
+	} else {
 		spin_unlock_irq(&dev->power.lock);
 
 		retval = cb(dev);
 
 		spin_lock_irq(&dev->power.lock);
+	}
 	dev->power.runtime_error = retval;
-
 	return retval;
 }
 
@@ -404,7 +407,7 @@ static int rpm_suspend(struct device *dev, int rpmflags)
 		goto out;
 	}
 
-	if (parent && !parent->power.ignore_children) {
+	if (parent && !parent->power.ignore_children && !dev->power.irq_safe) {
 		spin_unlock_irq(&dev->power.lock);
 
 		pm_request_idle(parent);
@@ -527,10 +530,13 @@ static int rpm_resume(struct device *dev, int rpmflags)
 
 	if (!parent && dev->parent) {
 		/*
-		 * Increment the parent's resume counter and resume it if
-		 * necessary.
+		 * Increment the parent's usage counter and resume it if
+		 * necessary.  Not needed if dev is irq-safe; then the
+		 * parent is permanently resumed.
 		 */
 		parent = dev->parent;
+		if (dev->power.irq_safe)
+			goto skip_parent;
 		spin_unlock(&dev->power.lock);
 
 		pm_runtime_get_noresume(parent);
@@ -553,6 +559,7 @@ static int rpm_resume(struct device *dev, int rpmflags)
 			goto out;
 		goto repeat;
 	}
+ skip_parent:
 
 	if (dev->power.no_callbacks)
 		goto no_callback;	/* Assume success. */
@@ -584,7 +591,7 @@ static int rpm_resume(struct device *dev, int rpmflags)
 		rpm_idle(dev, RPM_ASYNC);
 
  out:
-	if (parent) {
+	if (parent && !dev->power.irq_safe) {
 		spin_unlock_irq(&dev->power.lock);
 
 		pm_runtime_put(parent);
@@ -1065,7 +1072,6 @@ EXPORT_SYMBOL_GPL(pm_runtime_allow);
  * Set the power.no_callbacks flag, which tells the PM core that this
  * device is power-managed through its parent and has no run-time PM
  * callbacks of its own.  The run-time sysfs attributes will be removed.
- *
  */
 void pm_runtime_no_callbacks(struct device *dev)
 {
@@ -1077,6 +1083,27 @@ void pm_runtime_no_callbacks(struct device *dev)
 }
 EXPORT_SYMBOL_GPL(pm_runtime_no_callbacks);
 
+/**
+ * pm_runtime_irq_safe - Leave interrupts disabled during callbacks.
+ * @dev: Device to handle
+ *
+ * Set the power.irq_safe flag, which tells the PM core that the
+ * ->runtime_suspend() and ->runtime_resume() callbacks for this device should
+ * always be invoked with the spinlock held and interrupts disabled.  It also
+ * causes the parent's usage counter to be permanently incremented, preventing
+ * the parent from runtime suspending -- otherwise an irq-safe child might have
+ * to wait for a non-irq-safe parent.
+ */
+void pm_runtime_irq_safe(struct device *dev)
+{
+	if (dev->parent)
+		pm_runtime_get_sync(dev->parent);
+	spin_lock_irq(&dev->power.lock);
+	dev->power.irq_safe = 1;
+	spin_unlock_irq(&dev->power.lock);
+}
+EXPORT_SYMBOL_GPL(pm_runtime_irq_safe);
+
 /**
  * update_autosuspend - Handle a change to a device's autosuspend settings.
  * @dev: Device to handle.
@@ -1199,4 +1226,6 @@ void pm_runtime_remove(struct device *dev)
 	/* Change the status back to 'suspended' to match the initial status. */
 	if (dev->power.runtime_status == RPM_ACTIVE)
 		pm_runtime_set_suspended(dev);
+	if (dev->power.irq_safe && dev->parent)
+		pm_runtime_put_sync(dev->parent);
 }

drivers/base/power/wakeup.c

@@ -542,26 +542,26 @@ static void pm_wakeup_update_hit_counts(void)
 }
 
 /**
- * pm_check_wakeup_events - Check for new wakeup events.
+ * pm_wakeup_pending - Check if power transition in progress should be aborted.
  *
  * Compare the current number of registered wakeup events with its preserved
- * value from the past to check if new wakeup events have been registered since
- * the old value was stored.  Check if the current number of wakeup events being
- * processed is zero.
+ * value from the past and return true if new wakeup events have been registered
+ * since the old value was stored.  Also return true if the current number of
+ * wakeup events being processed is different from zero.
  */
-bool pm_check_wakeup_events(void)
+bool pm_wakeup_pending(void)
 {
 	unsigned long flags;
-	bool ret = true;
+	bool ret = false;
 
 	spin_lock_irqsave(&events_lock, flags);
 	if (events_check_enabled) {
-		ret = ((unsigned int)atomic_read(&event_count) == saved_count)
-			&& !atomic_read(&events_in_progress);
-		events_check_enabled = ret;
+		ret = ((unsigned int)atomic_read(&event_count) != saved_count)
+			|| atomic_read(&events_in_progress);
+		events_check_enabled = !ret;
 	}
 	spin_unlock_irqrestore(&events_lock, flags);
-	if (!ret)
+	if (ret)
 		pm_wakeup_update_hit_counts();
 	return ret;
 }

drivers/spi/spi.c

@@ -28,6 +28,7 @@
 #include <linux/mod_devicetable.h>
 #include <linux/spi/spi.h>
 #include <linux/of_spi.h>
+#include <linux/pm_runtime.h>
 
 static void spidev_release(struct device *dev)
 {
@@ -100,9 +101,8 @@ static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
 	return 0;
 }
 
-#ifdef	CONFIG_PM
-
-static int spi_suspend(struct device *dev, pm_message_t message)
+#ifdef CONFIG_PM_SLEEP
+static int spi_legacy_suspend(struct device *dev, pm_message_t message)
 {
 	int			value = 0;
 	struct spi_driver	*drv = to_spi_driver(dev->driver);
@@ -117,7 +117,7 @@ static int spi_suspend(struct device *dev, pm_message_t message)
 	return value;
 }
 
-static int spi_resume(struct device *dev)
+static int spi_legacy_resume(struct device *dev)
 {
 	int			value = 0;
 	struct spi_driver	*drv = to_spi_driver(dev->driver);
@@ -132,18 +132,94 @@ static int spi_resume(struct device *dev)
 	return value;
 }
 
+static int spi_pm_suspend(struct device *dev)
+{
+	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
+
+	if (pm)
+		return pm_generic_suspend(dev);
+	else
+		return spi_legacy_suspend(dev, PMSG_SUSPEND);
+}
+
+static int spi_pm_resume(struct device *dev)
+{
+	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
+
+	if (pm)
+		return pm_generic_resume(dev);
+	else
+		return spi_legacy_resume(dev);
+}
+
+static int spi_pm_freeze(struct device *dev)
+{
+	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
+
+	if (pm)
+		return pm_generic_freeze(dev);
+	else
+		return spi_legacy_suspend(dev, PMSG_FREEZE);
+}
+
+static int spi_pm_thaw(struct device *dev)
+{
+	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
+
+	if (pm)
+		return pm_generic_thaw(dev);
+	else
+		return spi_legacy_resume(dev);
+}
+
+static int spi_pm_poweroff(struct device *dev)
+{
+	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
+
+	if (pm)
+		return pm_generic_poweroff(dev);
+	else
+		return spi_legacy_suspend(dev, PMSG_HIBERNATE);
+}
+
+static int spi_pm_restore(struct device *dev)
+{
+	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
+
+	if (pm)
+		return pm_generic_restore(dev);
+	else
+		return spi_legacy_resume(dev);
+}
 #else
-#define spi_suspend	NULL
-#define spi_resume	NULL
+#define spi_pm_suspend	NULL
+#define spi_pm_resume	NULL
+#define spi_pm_freeze	NULL
+#define spi_pm_thaw	NULL
+#define spi_pm_poweroff	NULL
+#define spi_pm_restore	NULL
 #endif
 
+static const struct dev_pm_ops spi_pm = {
+	.suspend = spi_pm_suspend,
+	.resume = spi_pm_resume,
+	.freeze = spi_pm_freeze,
+	.thaw = spi_pm_thaw,
+	.poweroff = spi_pm_poweroff,
+	.restore = spi_pm_restore,
+	SET_RUNTIME_PM_OPS(
+		pm_generic_runtime_suspend,
+		pm_generic_runtime_resume,
+		pm_generic_runtime_idle
+	)
+};
+
 struct bus_type spi_bus_type = {
 	.name		= "spi",
 	.dev_attrs	= spi_dev_attrs,
 	.match		= spi_match_device,
 	.uevent		= spi_uevent,
-	.suspend	= spi_suspend,
-	.resume		= spi_resume,
+	.pm		= &spi_pm,
 };
 EXPORT_SYMBOL_GPL(spi_bus_type);
 

drivers/usb/core/driver.c

@@ -375,7 +375,7 @@ static int usb_unbind_interface(struct device *dev)
 		 * Just re-enable it without affecting the endpoint toggles.
 		 */
 		usb_enable_interface(udev, intf, false);
-	} else if (!error && intf->dev.power.status == DPM_ON) {
+	} else if (!error && !intf->dev.power.in_suspend) {
 		r = usb_set_interface(udev, intf->altsetting[0].
 				desc.bInterfaceNumber, 0);
 		if (r < 0)
@@ -960,7 +960,7 @@ void usb_rebind_intf(struct usb_interface *intf)
 	}
 
 	/* Try to rebind the interface */
-	if (intf->dev.power.status == DPM_ON) {
+	if (!intf->dev.power.in_suspend) {
 		intf->needs_binding = 0;
 		rc = device_attach(&intf->dev);
 		if (rc < 0)
@@ -1107,8 +1107,7 @@ static int usb_resume_interface(struct usb_device *udev,
 	if (intf->condition == USB_INTERFACE_UNBOUND) {
 
 		/* Carry out a deferred switch to altsetting 0 */
-		if (intf->needs_altsetting0 &&
-				intf->dev.power.status == DPM_ON) {
+		if (intf->needs_altsetting0 && !intf->dev.power.in_suspend) {
 			usb_set_interface(udev, intf->altsetting[0].
 					desc.bInterfaceNumber, 0);
 			intf->needs_altsetting0 = 0;

include/linux/device.h

@@ -508,13 +508,13 @@ static inline int device_is_registered(struct device *dev)
 
 static inline void device_enable_async_suspend(struct device *dev)
 {
-	if (dev->power.status == DPM_ON)
+	if (!dev->power.in_suspend)
 		dev->power.async_suspend = true;
 }
 
 static inline void device_disable_async_suspend(struct device *dev)
 {
-	if (dev->power.status == DPM_ON)
+	if (!dev->power.in_suspend)
 		dev->power.async_suspend = false;
 }
 

include/linux/pm.h

@@ -366,45 +366,6 @@ extern struct dev_pm_ops generic_subsys_pm_ops;
 #define PMSG_AUTO_RESUME	((struct pm_message) \
 					{ .event = PM_EVENT_AUTO_RESUME, })
 
-/**
- * Device power management states
- *
- * These state labels are used internally by the PM core to indicate the current
- * status of a device with respect to the PM core operations.
- *
- * DPM_ON		Device is regarded as operational.  Set this way
- *			initially and when ->complete() is about to be called.
- *			Also set when ->prepare() fails.
- *
- * DPM_PREPARING	Device is going to be prepared for a PM transition.  Set
- *			when ->prepare() is about to be called.
- *
- * DPM_RESUMING		Device is going to be resumed.  Set when ->resume(),
- *			->thaw(), or ->restore() is about to be called.
- *
- * DPM_SUSPENDING	Device has been prepared for a power transition.  Set
- *			when ->prepare() has just succeeded.
- *
- * DPM_OFF		Device is regarded as inactive.  Set immediately after
- *			->suspend(), ->freeze(), or ->poweroff() has succeeded.
- *			Also set when ->resume()_noirq, ->thaw_noirq(), or
- *			->restore_noirq() is about to be called.
- *
- * DPM_OFF_IRQ		Device is in a "deep sleep".  Set immediately after
- *			->suspend_noirq(), ->freeze_noirq(), or
- *			->poweroff_noirq() has just succeeded.
- */
-
-enum dpm_state {
-	DPM_INVALID,
-	DPM_ON,
-	DPM_PREPARING,
-	DPM_RESUMING,
-	DPM_SUSPENDING,
-	DPM_OFF,
-	DPM_OFF_IRQ,
-};
-
 /**
  * Device run-time power management status.
  *
@@ -463,8 +424,8 @@ struct wakeup_source;
 struct dev_pm_info {
 	pm_message_t		power_state;
 	unsigned int		can_wakeup:1;
-	unsigned		async_suspend:1;
-	enum dpm_state		status;		/* Owned by the PM core */
+	unsigned int		async_suspend:1;
+	unsigned int		in_suspend:1;	/* Owned by the PM core */
 	spinlock_t		lock;
 #ifdef CONFIG_PM_SLEEP
 	struct list_head	entry;
@@ -486,6 +447,7 @@ struct dev_pm_info {
 	unsigned int		run_wake:1;
 	unsigned int		runtime_auto:1;
 	unsigned int		no_callbacks:1;
+	unsigned int		irq_safe:1;
 	unsigned int		use_autosuspend:1;
 	unsigned int		timer_autosuspends:1;
 	enum rpm_request	request;
@@ -610,4 +572,11 @@ extern unsigned int	pm_flags;
 #define PM_APM	1
 #define PM_ACPI	2
 
+extern int pm_generic_suspend(struct device *dev);
+extern int pm_generic_resume(struct device *dev);
+extern int pm_generic_freeze(struct device *dev);
+extern int pm_generic_thaw(struct device *dev);
+extern int pm_generic_restore(struct device *dev);
+extern int pm_generic_poweroff(struct device *dev);
+
 #endif /* _LINUX_PM_H */

include/linux/pm_runtime.h

@@ -40,6 +40,7 @@ extern int pm_generic_runtime_idle(struct device *dev);
 extern int pm_generic_runtime_suspend(struct device *dev);
 extern int pm_generic_runtime_resume(struct device *dev);
 extern void pm_runtime_no_callbacks(struct device *dev);
+extern void pm_runtime_irq_safe(struct device *dev);
 extern void __pm_runtime_use_autosuspend(struct device *dev, bool use);
 extern void pm_runtime_set_autosuspend_delay(struct device *dev, int delay);
 extern unsigned long pm_runtime_autosuspend_expiration(struct device *dev);
@@ -81,6 +82,11 @@ static inline bool pm_runtime_suspended(struct device *dev)
 		&& !dev->power.disable_depth;
 }
 
+static inline bool pm_runtime_enabled(struct device *dev)
+{
+	return !dev->power.disable_depth;
+}
+
 static inline void pm_runtime_mark_last_busy(struct device *dev)
 {
 	ACCESS_ONCE(dev->power.last_busy) = jiffies;
@@ -119,11 +125,13 @@ static inline void pm_runtime_put_noidle(struct device *dev) {}
 static inline bool device_run_wake(struct device *dev) { return false; }
 static inline void device_set_run_wake(struct device *dev, bool enable) {}
 static inline bool pm_runtime_suspended(struct device *dev) { return false; }
+static inline bool pm_runtime_enabled(struct device *dev) { return false; }
 
 static inline int pm_generic_runtime_idle(struct device *dev) { return 0; }
 static inline int pm_generic_runtime_suspend(struct device *dev) { return 0; }
 static inline int pm_generic_runtime_resume(struct device *dev) { return 0; }
 static inline void pm_runtime_no_callbacks(struct device *dev) {}
+static inline void pm_runtime_irq_safe(struct device *dev) {}
 
 static inline void pm_runtime_mark_last_busy(struct device *dev) {}
 static inline void __pm_runtime_use_autosuspend(struct device *dev,
@@ -196,6 +204,11 @@ static inline int pm_runtime_put_sync(struct device *dev)
 	return __pm_runtime_idle(dev, RPM_GET_PUT);
 }
 
+static inline int pm_runtime_put_sync_suspend(struct device *dev)
+{
+	return __pm_runtime_suspend(dev, RPM_GET_PUT);
+}
+
 static inline int pm_runtime_put_sync_autosuspend(struct device *dev)
 {
 	return __pm_runtime_suspend(dev, RPM_GET_PUT | RPM_AUTO);

include/linux/suspend.h

@@ -292,7 +292,7 @@ extern int unregister_pm_notifier(struct notifier_block *nb);
 /* drivers/base/power/wakeup.c */
 extern bool events_check_enabled;
 
-extern bool pm_check_wakeup_events(void);
+extern bool pm_wakeup_pending(void);
 extern bool pm_get_wakeup_count(unsigned int *count);
 extern bool pm_save_wakeup_count(unsigned int count);
 #else /* !CONFIG_PM_SLEEP */
@@ -309,7 +309,7 @@ static inline int unregister_pm_notifier(struct notifier_block *nb)
 
 #define pm_notifier(fn, pri)	do { (void)(fn); } while (0)
 
-static inline bool pm_check_wakeup_events(void) { return true; }
+static inline bool pm_wakeup_pending(void) { return false; }
 #endif /* !CONFIG_PM_SLEEP */
 
 extern struct mutex pm_mutex;

kernel/freezer.c

@@ -104,8 +104,13 @@ bool freeze_task(struct task_struct *p, bool sig_only)
 	}
 
 	if (should_send_signal(p)) {
-		if (!signal_pending(p))
 		fake_signal_wake_up(p);
+		/*
+		 * fake_signal_wake_up() goes through p's scheduler
+		 * lock and guarantees that TASK_STOPPED/TRACED ->
+		 * TASK_RUNNING transition can't race with task state
+		 * testing in try_to_freeze_tasks().
+		 */
 	} else if (sig_only) {
 		return false;
 	} else {

kernel/power/Makefile

-
-ifeq ($(CONFIG_PM_DEBUG),y)
-EXTRA_CFLAGS	+=	-DDEBUG
-endif
+ccflags-$(CONFIG_PM_DEBUG)	:=	-DDEBUG
 
 obj-$(CONFIG_PM)		+= main.o
 obj-$(CONFIG_PM_SLEEP)		+= console.o

kernel/power/hibernate.c

@@ -62,7 +62,7 @@ void hibernation_set_ops(struct platform_hibernation_ops *ops)
 {
 	if (ops && !(ops->begin && ops->end &&  ops->pre_snapshot
 	    && ops->prepare && ops->finish && ops->enter && ops->pre_restore
-	    && ops->restore_cleanup)) {
+	    && ops->restore_cleanup && ops->leave)) {
 		WARN_ON(1);
 		return;
 	}
@@ -278,7 +278,7 @@ static int create_image(int platform_mode)
 		goto Enable_irqs;
 	}
 
-	if (hibernation_test(TEST_CORE) || !pm_check_wakeup_events())
+	if (hibernation_test(TEST_CORE) || pm_wakeup_pending())
 		goto Power_up;
 
 	in_suspend = 1;
@@ -516,7 +516,7 @@ int hibernation_platform_enter(void)
 
 	local_irq_disable();
 	sysdev_suspend(PMSG_HIBERNATE);
-	if (!pm_check_wakeup_events()) {
+	if (pm_wakeup_pending()) {
 		error = -EAGAIN;
 		goto Power_up;
 	}
@@ -647,6 +647,7 @@ int hibernate(void)
 		swsusp_free();
 		if (!error)
 			power_down();
+		in_suspend = 0;
 		pm_restore_gfp_mask();
 	} else {
 		pr_debug("PM: Image restored successfully.\n");

kernel/power/process.c

@@ -64,6 +64,12 @@ static int try_to_freeze_tasks(bool sig_only)
 			 * perturb a task in TASK_STOPPED or TASK_TRACED.
 			 * It is "frozen enough".  If the task does wake
 			 * up, it will immediately call try_to_freeze.
+			 *
+			 * Because freeze_task() goes through p's
+			 * scheduler lock after setting TIF_FREEZE, it's
+			 * guaranteed that either we see TASK_RUNNING or
+			 * try_to_stop() after schedule() in ptrace/signal
+			 * stop sees TIF_FREEZE.
 			 */
 			if (!task_is_stopped_or_traced(p) &&
 			    !freezer_should_skip(p))
@@ -79,7 +85,7 @@ static int try_to_freeze_tasks(bool sig_only)
 		if (!todo || time_after(jiffies, end_time))
 			break;
 
-		if (!pm_check_wakeup_events()) {
+		if (pm_wakeup_pending()) {
 			wakeup = true;
 			break;
 		}

kernel/power/suspend.c

@@ -164,7 +164,7 @@ static int suspend_enter(suspend_state_t state)
 
 	error = sysdev_suspend(PMSG_SUSPEND);
 	if (!error) {
-		if (!suspend_test(TEST_CORE) && pm_check_wakeup_events()) {
+		if (!(suspend_test(TEST_CORE) || pm_wakeup_pending())) {
 			error = suspend_ops->enter(state);
 			events_check_enabled = false;
 		}