devices: unregister children when unregistering a device

We currently do not allow to unregister a device when it
has children. However, the return value is seldomly checked.
Also this breaks for hot pluggable devices like USB which we have
to unregister when they disappear. The best way to fix this is to
unregister our children and also the partitions on the unregistered
device.
We unregister the device first and then afterwards the children.
We do this because for example network devices have a miidev as
child which they unregister themselves. So we only have to
unregister the children which are not cleaned up by the drivers,
namely fs devices.
Also, unregister all partitions on a disappearing device.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 15 insertions, 5 deletions

diff --git a/drivers/base/driver.c b/drivers/base/driver.c
index 0132e7dcf8..3777f82d64 100644
--- a/drivers/base/driver.c
+++ b/drivers/base/driver.c
@@ -137,16 +137,26 @@ EXPORT_SYMBOL(register_device);
 
 int unregister_device(struct device_d *old_dev)
 {
-	debug("unregister_device: %s\n", dev_name(old_dev));
+	struct cdev *cdev, *ct;
+	struct device_d *child, *dt;
 
-	if (!list_empty(&old_dev->children)) {
-		errno = -EBUSY;
-		return errno;
-	}
+	dev_dbg(old_dev, "unregister\n");
 
 	if (old_dev->driver)
 		old_dev->bus->remove(old_dev);
 
+	list_for_each_entry_safe(child, dt, &old_dev->children, sibling) {
+		dev_dbg(old_dev, "unregister child %s\n", dev_name(child));
+		unregister_device(child);
+	}
+
+	list_for_each_entry_safe(cdev, ct, &old_dev->cdevs, devices_list) {
+		if (cdev->flags & DEVFS_IS_PARTITION) {
+			dev_dbg(old_dev, "unregister part %s\n", cdev->name);
+			devfs_del_partition(cdev->name);
+		}
+	}
+
 	list_del(&old_dev->list);
 	list_del(&old_dev->active);