[media] dvbdev: returns error if graph object creation fails

Right now, if something gets wrong at dvb_create_media_entity()
or at dvb_create_media_graph(), the device will still be
registered.

Change the logic to properly handle it and free all media graph
objects if something goes wrong at dvb_register_device().

Also, change the logic at dvb_create_media_graph() to return
an error code if something goes wrong. It is up to the
caller to implement the right logic and to call
dvb_unregister_device() to unregister the already-created
objects.

While here, add a missing logic to unregister the created
interfaces.
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

drivers/media/dvb-core/dvbdev.h

@@ -206,7 +206,7 @@ int dvb_register_device(struct dvb_adapter *adap,
 void dvb_unregister_device(struct dvb_device *dvbdev);
 
 #ifdef CONFIG_MEDIA_CONTROLLER_DVB
-void dvb_create_media_graph(struct dvb_adapter *adap);
+int dvb_create_media_graph(struct dvb_adapter *adap);
 static inline void dvb_register_media_controller(struct dvb_adapter *adap,
 						 struct media_device *mdev)
 {
@@ -214,7 +214,10 @@ static inline void dvb_register_media_controller(struct dvb_adapter *adap,
 }
 
 #else
-static inline void dvb_create_media_graph(struct dvb_adapter *adap) {}
+static inline int dvb_create_media_graph(struct dvb_adapter *adap)
+{
+	return 0;
+};
 #define dvb_register_media_controller(a, b) {}
 #endif
 

drivers/media/media-device.c

@@ -576,6 +576,10 @@ void media_device_unregister(struct media_device *mdev)
 	struct media_entity *next;
 	struct media_interface *intf, *tmp_intf;
 
+	/* Remove all entities from the media device */
+	list_for_each_entry_safe(entity, next, &mdev->entities, graph_obj.list)
+		media_device_unregister_entity(entity);
+
 	/* Remove all interfaces from the media device */
 	spin_lock(&mdev->lock);
 	list_for_each_entry_safe(intf, tmp_intf, &mdev->interfaces,
@@ -586,9 +590,6 @@ void media_device_unregister(struct media_device *mdev)
 	}
 	spin_unlock(&mdev->lock);
 
-	list_for_each_entry_safe(entity, next, &mdev->entities, graph_obj.list)
-		media_device_unregister_entity(entity);
-
 	device_remove_file(&mdev->devnode.dev, &dev_attr_model);
 	media_devnode_unregister(&mdev->devnode);
 
@@ -654,8 +655,7 @@ void media_device_unregister_entity(struct media_entity *entity)
 	/* Remove all interface links pointing to this entity */
 	list_for_each_entry(intf, &mdev->interfaces, graph_obj.list) {
 		list_for_each_entry_safe(link, tmp, &intf->links, list) {
-			if (media_type(link->gobj1) == MEDIA_GRAPH_ENTITY
-			    && link->entity == entity)
+			if (link->entity == entity)
 				__media_remove_intf_link(link);
 		}
 	}