Merge branches 'pm-sleep' and 'pm-runtime' into pm-core

drivers/base/base.h

@@ -131,6 +131,8 @@ extern void device_remove_groups(struct device *dev,
 extern char *make_class_name(const char *name, struct kobject *kobj);
 
 extern int devres_release_all(struct device *dev);
+extern void device_block_probing(void);
+extern void device_unblock_probing(void);
 
 /* /sys/devices directory */
 extern struct kset *devices_kset;

drivers/base/dd.c

@@ -54,6 +54,13 @@ static LIST_HEAD(deferred_probe_active_list);
 static struct workqueue_struct *deferred_wq;
 static atomic_t deferred_trigger_count = ATOMIC_INIT(0);
 
+/*
+ * In some cases, like suspend to RAM or hibernation, It might be reasonable
+ * to prohibit probing of devices as it could be unsafe.
+ * Once defer_all_probes is true all drivers probes will be forcibly deferred.
+ */
+static bool defer_all_probes;
+
 /*
  * deferred_probe_work_func() - Retry probing devices in the active list.
  */
@@ -171,6 +178,30 @@ static void driver_deferred_probe_trigger(void)
 	queue_work(deferred_wq, &deferred_probe_work);
 }
 
+/**
+ * device_block_probing() - Block/defere device's probes
+ *
+ *	It will disable probing of devices and defer their probes instead.
+ */
+void device_block_probing(void)
+{
+	defer_all_probes = true;
+	/* sync with probes to avoid races. */
+	wait_for_device_probe();
+}
+
+/**
+ * device_unblock_probing() - Unblock/enable device's probes
+ *
+ *	It will restore normal behavior and trigger re-probing of deferred
+ * devices.
+ */
+void device_unblock_probing(void)
+{
+	defer_all_probes = false;
+	driver_deferred_probe_trigger();
+}
+
 /**
  * deferred_probe_initcall() - Enable probing of deferred devices
  *
@@ -277,9 +308,20 @@ static DECLARE_WAIT_QUEUE_HEAD(probe_waitqueue);
 
 static int really_probe(struct device *dev, struct device_driver *drv)
 {
-	int ret = 0;
+	int ret = -EPROBE_DEFER;
 	int local_trigger_count = atomic_read(&deferred_trigger_count);
 
+	if (defer_all_probes) {
+		/*
+		 * Value of defer_all_probes can be set only by
+		 * device_defer_all_probes_enable() which, in turn, will call
+		 * wait_for_device_probe() right after that to avoid any races.
+		 */
+		dev_dbg(dev, "Driver %s force probe deferral\n", drv->name);
+		driver_deferred_probe_add(dev);
+		return ret;
+	}
+
 	atomic_inc(&probe_count);
 	pr_debug("bus: '%s': %s: probing driver %s with device %s\n",
 		 drv->bus->name, __func__, drv->name, dev_name(dev));
@@ -340,6 +382,7 @@ probe_failed:
 	dev_set_drvdata(dev, NULL);
 	if (dev->pm_domain && dev->pm_domain->dismiss)
 		dev->pm_domain->dismiss(dev);
+	pm_runtime_reinit(dev);
 
 	switch (ret) {
 	case -EPROBE_DEFER:
@@ -393,6 +436,10 @@ int driver_probe_done(void)
  */
 void wait_for_device_probe(void)
 {
+	/* wait for the deferred probe workqueue to finish */
+	if (driver_deferred_probe_enable)
+		flush_workqueue(deferred_wq);
+
 	/* wait for the known devices to complete their probing */
 	wait_event(probe_waitqueue, atomic_read(&probe_count) == 0);
 	async_synchronize_full();
@@ -695,6 +742,7 @@ static void __device_release_driver(struct device *dev)
 		dev_set_drvdata(dev, NULL);
 		if (dev->pm_domain && dev->pm_domain->dismiss)
 			dev->pm_domain->dismiss(dev);
+		pm_runtime_reinit(dev);
 
 		klist_remove(&dev->p->knode_driver);
 		if (dev->bus)

drivers/base/power/main.c

@@ -963,6 +963,9 @@ void dpm_complete(pm_message_t state)
 	}
 	list_splice(&list, &dpm_list);
 	mutex_unlock(&dpm_list_mtx);
+
+	/* Allow device probing and trigger re-probing of deferred devices */
+	device_unblock_probing();
 	trace_suspend_resume(TPS("dpm_complete"), state.event, false);
 }
 
@@ -1624,6 +1627,20 @@ int dpm_prepare(pm_message_t state)
 	trace_suspend_resume(TPS("dpm_prepare"), state.event, true);
 	might_sleep();
 
+	/*
+	 * Give a chance for the known devices to complete their probes, before
+	 * disable probing of devices. This sync point is important at least
+	 * at boot time + hibernation restore.
+	 */
+	wait_for_device_probe();
+	/*
+	 * It is unsafe if probing of devices will happen during suspend or
+	 * hibernation and system behavior will be unpredictable in this case.
+	 * So, let's prohibit device's probing here and defer their probes
+	 * instead. The normal behavior will be restored in dpm_complete().
+	 */
+	device_block_probing();
+
 	mutex_lock(&dpm_list_mtx);
 	while (!list_empty(&dpm_list)) {
 		struct device *dev = to_device(dpm_list.next);

drivers/base/power/power.h

@@ -18,6 +18,7 @@ static inline void pm_runtime_early_init(struct device *dev)
 }
 
 extern void pm_runtime_init(struct device *dev);
+extern void pm_runtime_reinit(struct device *dev);
 extern void pm_runtime_remove(struct device *dev);
 
 struct wake_irq {
@@ -84,6 +85,7 @@ static inline void pm_runtime_early_init(struct device *dev)
 }
 
 static inline void pm_runtime_init(struct device *dev) {}
+static inline void pm_runtime_reinit(struct device *dev) {}
 static inline void pm_runtime_remove(struct device *dev) {}
 
 static inline int dpm_sysfs_add(struct device *dev) { return 0; }

drivers/base/power/runtime.c

@@ -1389,6 +1389,25 @@ void pm_runtime_init(struct device *dev)
 	init_waitqueue_head(&dev->power.wait_queue);
 }
 
+/**
+ * pm_runtime_reinit - Re-initialize runtime PM fields in given device object.
+ * @dev: Device object to re-initialize.
+ */
+void pm_runtime_reinit(struct device *dev)
+{
+	if (!pm_runtime_enabled(dev)) {
+		if (dev->power.runtime_status == RPM_ACTIVE)
+			pm_runtime_set_suspended(dev);
+		if (dev->power.irq_safe) {
+			spin_lock_irq(&dev->power.lock);
+			dev->power.irq_safe = 0;
+			spin_unlock_irq(&dev->power.lock);
+			if (dev->parent)
+				pm_runtime_put(dev->parent);
+		}
+	}
+}
+
 /**
  * pm_runtime_remove - Prepare for removing a device from device hierarchy.
  * @dev: Device object being removed from device hierarchy.
@@ -1396,12 +1415,7 @@ void pm_runtime_init(struct device *dev)
 void pm_runtime_remove(struct device *dev)
 {
 	__pm_runtime_disable(dev, false);
-
-	/* 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(dev->parent);
+	pm_runtime_reinit(dev);
 }
 
 /**