Commit 4ebddb7c authored by Sakari Ailus's avatar Sakari Ailus Committed by Mauro Carvalho Chehab
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media: entity: Add lockdep check to media graph walk 



It was always assumed that walking the media graph would require holding
the media_device graph_mutex but this was not documented nor checked for.

Add a lockdep check to graph walk init and iter, and document the need for
acquiring the graph_mutex.

Signed-off-by: default avatarSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab+huawei@kernel.org>
parent 5bf2c8b6

drivers/media/mc/mc-entity.c

+1 −0
Original line number Diff line number Diff line
@@ -340,6 +340,7 @@ static void media_graph_walk_iter(struct media_graph *graph) 
	stack_push(graph, next);

	dev_dbg(entity->graph_obj.mdev->dev, "walk: pushing '%s' on stack\n",

		next->name);

	lockdep_assert_held(&entity->graph_obj.mdev->graph_mutex);

}



struct media_entity *media_graph_walk_next(struct media_graph *graph)

include/media/media-entity.h

+5 −0
Original line number Diff line number Diff line
@@ -885,6 +885,11 @@ int media_entity_get_fwnode_pad(struct media_entity *entity, 
 *

 * @graph: Media graph structure that will be used to walk the graph

 * @mdev: Pointer to the &media_device that contains the object

 *

 * The caller is required to hold the media_device graph_mutex during the graph

 * walk until the graph state is released.

 *

 * Returns zero on success or a negative error code otherwise.

 */

__must_check int media_graph_walk_init(

	struct media_graph *graph, struct media_device *mdev);