Add media_entity_graph_walk_init() and media_entity_graph_walk_cleanup()
functions in order to dynamically allocate memory for the graph. This is
not done in media_entity_graph_walk_start() as there are situations where
e.g. correct error handling, that itself may not fail, requires successful
graph walk.
Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
---
drivers/media/media-entity.c | 39 ++++++++++++++++++++++++++++++++++-----
include/media/media-entity.h | 5 ++++-
2 files changed, 38 insertions(+), 6 deletions(-)
diff --git a/drivers/media/media-entity.c b/drivers/media/media-entity.c
index 667ab32..bf3c31f 100644
--- a/drivers/media/media-entity.c
+++ b/drivers/media/media-entity.c
@@ -353,14 +353,44 @@ static struct media_entity *stack_pop(struct media_entity_graph *graph)
#define stack_top(en) ((en)->stack[(en)->top].entity)
/**
+ * media_entity_graph_walk_init - Allocate resources for graph walk
+ * @graph: Media graph structure that will be used to walk the graph
+ * @mdev: Media device
+ *
+ * Reserve resources for graph walk in media device's current
+ * state. The memory must be released using
+ * media_entity_graph_walk_free().
+ *
+ * Returns error on failure, zero on success.
+ */
+__must_check int media_entity_graph_walk_init(
+ struct media_entity_graph *graph, struct media_device *mdev)
+{
+ return 0;
+}
+EXPORT_SYMBOL_GPL(media_entity_graph_walk_init);
+
+/**
+ * media_entity_graph_walk_cleanup - Release resources related to graph walking
+ * @graph: Media graph structure that was used to walk the graph
+ */
+void media_entity_graph_walk_cleanup(struct media_entity_graph *graph)
+{
+}
+EXPORT_SYMBOL_GPL(media_entity_graph_walk_cleanup);
+
+/**
* media_entity_graph_walk_start - Start walking the media graph at a given entity
* @graph: Media graph structure that will be used to walk the graph
* @entity: Starting entity
*
- * This function initializes the graph traversal structure to walk the entities
- * graph starting at the given entity. The traversal structure must not be
- * modified by the caller during graph traversal. When done the structure can
- * safely be freed.
+ * Before using this function, media_entity_graph_walk_init() must be
+ * used to allocate resources used for walking the graph. This
+ * function initializes the graph traversal structure to walk the
+ * entities graph starting at the given entity. The traversal
+ * structure must not be modified by the caller during graph
+ * traversal. After the graph walk, the resources must be released
+ * using media_entity_graph_walk_cleanup().
*/
void media_entity_graph_walk_start(struct media_entity_graph *graph,
struct media_entity *entity)
@@ -377,7 +407,6 @@ void media_entity_graph_walk_start(struct media_entity_graph *graph,
}
EXPORT_SYMBOL_GPL(media_entity_graph_walk_start);
-
/**
* media_entity_graph_walk_next - Get the next entity in the graph
* @graph: Media graph structure
diff --git a/include/media/media-entity.h b/include/media/media-entity.h
index 4b5ca39..f0652e2 100644
--- a/include/media/media-entity.h
+++ b/include/media/media-entity.h
@@ -506,8 +506,11 @@ struct media_pad *media_entity_remote_pad(struct media_pad *pad);
struct media_entity *media_entity_get(struct media_entity *entity);
void media_entity_put(struct media_entity *entity);
+__must_check int media_entity_graph_walk_init(
+ struct media_entity_graph *graph, struct media_device *mdev);
+void media_entity_graph_walk_cleanup(struct media_entity_graph *graph);
void media_entity_graph_walk_start(struct media_entity_graph *graph,
- struct media_entity *entity);
+ struct media_entity *entity);
struct media_entity *
media_entity_graph_walk_next(struct media_entity_graph *graph);
__must_check int media_entity_pipeline_start(struct media_entity *entity,
--
2.1.4
--
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