[PATCH v1 1/3] driver core: move core part of device_shutdown() to a separate function

[Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx>]

Split the device_shutdown() as a preparation for the prioritization
support.

Signed-off-by: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx>
---
 drivers/base/core.c | 110 +++++++++++++++++++++++++-------------------
 1 file changed, 63 insertions(+), 47 deletions(-)

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 67ba592afc77..0f5646a097d3 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -4719,12 +4719,73 @@ int device_change_owner(struct device *dev, kuid_t kuid, kgid_t kgid)
 }
 EXPORT_SYMBOL_GPL(device_change_owner);
 
+/**
+ * device_shutdown_one - shut down a device
+ * @dev: device to shut down
+ *
+ * It is called with the device lock held.
+ *
+ * The device must be on the devices_kset list.
+ */
+static void device_shutdown_one_locked(struct device *dev)
+{
+	struct device *parent;
+
+	lockdep_assert_held(&devices_kset->list_lock);
+	/*
+	 * hold reference count of device's parent to
+	 * prevent it from being freed because parent's
+	 * lock is to be held
+	 */
+	parent = get_device(dev->parent);
+	get_device(dev);
+	/*
+	 * Make sure the device is off the kset list, in the
+	 * event that dev->*->shutdown() doesn't remove it.
+	 */
+	list_del_init(&dev->kobj.entry);
+	spin_unlock(&devices_kset->list_lock);
+
+	/* hold lock to avoid race with probe/release */
+	if (parent)
+		device_lock(parent);
+	device_lock(dev);
+
+	/* Don't allow any more runtime suspends */
+	pm_runtime_get_noresume(dev);
+	pm_runtime_barrier(dev);
+
+	if (dev->class && dev->class->shutdown_pre) {
+		if (initcall_debug)
+			dev_info(dev, "shutdown_pre\n");
+		dev->class->shutdown_pre(dev);
+	}
+	if (dev->bus && dev->bus->shutdown) {
+		if (initcall_debug)
+			dev_info(dev, "shutdown\n");
+		dev->bus->shutdown(dev);
+	} else if (dev->driver && dev->driver->shutdown) {
+		if (initcall_debug)
+			dev_info(dev, "shutdown\n");
+		dev->driver->shutdown(dev);
+	}
+
+	device_unlock(dev);
+	if (parent)
+		device_unlock(parent);
+
+	put_device(dev);
+	put_device(parent);
+
+	spin_lock(&devices_kset->list_lock);
+}
+
 /**
  * device_shutdown - call ->shutdown() on each device to shutdown.
  */
 void device_shutdown(void)
 {
-	struct device *dev, *parent;
+	struct device *dev;
 
 	wait_for_device_probe();
 	device_block_probing();
@@ -4741,52 +4802,7 @@ void device_shutdown(void)
 		dev = list_entry(devices_kset->list.prev, struct device,
 				kobj.entry);
 
-		/*
-		 * hold reference count of device's parent to
-		 * prevent it from being freed because parent's
-		 * lock is to be held
-		 */
-		parent = get_device(dev->parent);
-		get_device(dev);
-		/*
-		 * Make sure the device is off the kset list, in the
-		 * event that dev->*->shutdown() doesn't remove it.
-		 */
-		list_del_init(&dev->kobj.entry);
-		spin_unlock(&devices_kset->list_lock);
-
-		/* hold lock to avoid race with probe/release */
-		if (parent)
-			device_lock(parent);
-		device_lock(dev);
-
-		/* Don't allow any more runtime suspends */
-		pm_runtime_get_noresume(dev);
-		pm_runtime_barrier(dev);
-
-		if (dev->class && dev->class->shutdown_pre) {
-			if (initcall_debug)
-				dev_info(dev, "shutdown_pre\n");
-			dev->class->shutdown_pre(dev);
-		}
-		if (dev->bus && dev->bus->shutdown) {
-			if (initcall_debug)
-				dev_info(dev, "shutdown\n");
-			dev->bus->shutdown(dev);
-		} else if (dev->driver && dev->driver->shutdown) {
-			if (initcall_debug)
-				dev_info(dev, "shutdown\n");
-			dev->driver->shutdown(dev);
-		}
-
-		device_unlock(dev);
-		if (parent)
-			device_unlock(parent);
-
-		put_device(dev);
-		put_device(parent);
-
-		spin_lock(&devices_kset->list_lock);
+		device_shutdown_one_locked(dev);
 	}
 	spin_unlock(&devices_kset->list_lock);
 }
-- 
2.39.2