Linux-libre 4.5-gnu

1 files changed, 76 insertions, 5 deletions

diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index a641cf3cc..c4da2df62 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -55,6 +55,13 @@ 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.
  */
 static void deferred_probe_work_func(struct work_struct *work)
@@ -172,6 +179,30 @@ static void driver_deferred_probe_trigger(void)
 }
 
 /**
+ * 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
  *
  * We don't want to get in the way when the bulk of drivers are getting probed.
@@ -192,9 +223,23 @@ static int deferred_probe_initcall(void)
 }
 late_initcall(deferred_probe_initcall);
 
+/**
+ * device_is_bound() - Check if device is bound to a driver
+ * @dev: device to check
+ *
+ * Returns true if passed device has already finished probing successfully
+ * against a driver.
+ *
+ * This function must be called with the device lock held.
+ */
+bool device_is_bound(struct device *dev)
+{
+	return dev->p && klist_node_attached(&dev->p->knode_driver);
+}
+
 static void driver_bound(struct device *dev)
 {
-	if (klist_node_attached(&dev->p->knode_driver)) {
+	if (device_is_bound(dev)) {
 		printk(KERN_WARNING "%s: device %s already bound\n",
 			__func__, kobject_name(&dev->kobj));
 		return;
@@ -205,6 +250,8 @@ static void driver_bound(struct device *dev)
 
 	klist_add_tail(&dev->p->knode_driver, &dev->driver->p->klist_devices);
 
+	device_pm_check_callbacks(dev);
+
 	/*
 	 * Make sure the device is no longer in one of the deferred lists and
 	 * kick off retrying all pending devices
@@ -268,6 +315,9 @@ int device_bind_driver(struct device *dev)
 	ret = driver_sysfs_add(dev);
 	if (!ret)
 		driver_bound(dev);
+	else if (dev->bus)
+		blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
+					     BUS_NOTIFY_DRIVER_NOT_BOUND, dev);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(device_bind_driver);
@@ -277,9 +327,20 @@ 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));
@@ -290,7 +351,7 @@ static int really_probe(struct device *dev, struct device_driver *drv)
 	/* If using pinctrl, bind pins now before probing */
 	ret = pinctrl_bind_pins(dev);
 	if (ret)
-		goto probe_failed;
+		goto pinctrl_bind_failed;
 
 	if (driver_sysfs_add(dev)) {
 		printk(KERN_ERR "%s: driver_sysfs_add(%s) failed\n",
@@ -334,12 +395,17 @@ static int really_probe(struct device *dev, struct device_driver *drv)
 	goto done;
 
 probe_failed:
+	if (dev->bus)
+		blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
+					     BUS_NOTIFY_DRIVER_NOT_BOUND, dev);
+pinctrl_bind_failed:
 	devres_release_all(dev);
 	driver_sysfs_remove(dev);
 	dev->driver = NULL;
 	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 +459,10 @@ 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();
@@ -547,7 +617,7 @@ static int __device_attach(struct device *dev, bool allow_async)
 
 	device_lock(dev);
 	if (dev->driver) {
-		if (klist_node_attached(&dev->p->knode_driver)) {
+		if (device_is_bound(dev)) {
 			ret = 1;
 			goto out_unlock;
 		}
@@ -695,13 +765,14 @@ 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);
+		device_pm_check_callbacks(dev);
 		if (dev->bus)
 			blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
 						     BUS_NOTIFY_UNBOUND_DRIVER,
 						     dev);
-
 	}
 }