[media] media: Add support for circular graph traversal
The graph traversal API (media_entity_graph_walk_*) doesn't support
cyclic graphs and will fail to correctly walk a graph when circular
links exist. Support circular graph traversal by checking whether an
entity has already been visited before pushing it to the stack.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Acked-by: Sakari Ailus <sakari.ailus@iki.fi>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
diff --git a/include/media/media-entity.h b/include/media/media-entity.h
index 06bacf9..10df551 100644
--- a/include/media/media-entity.h
+++ b/include/media/media-entity.h
@@ -23,6 +23,7 @@
#ifndef _MEDIA_ENTITY_H
#define _MEDIA_ENTITY_H
+#include <linux/bitops.h>
#include <linux/list.h>
#include <linux/media.h>
@@ -113,12 +114,15 @@
}
#define MEDIA_ENTITY_ENUM_MAX_DEPTH 16
+#define MEDIA_ENTITY_ENUM_MAX_ID 64
struct media_entity_graph {
struct {
struct media_entity *entity;
int link;
} stack[MEDIA_ENTITY_ENUM_MAX_DEPTH];
+
+ DECLARE_BITMAP(entities, MEDIA_ENTITY_ENUM_MAX_ID);
int top;
};