diff options
| author | Laurent Pinchart | 2013-06-07 12:45:11 -0300 |
|---|---|---|
| committer | Mauro Carvalho Chehab | 2013-08-18 07:16:48 -0300 |
| commit | 5c7b25b90d36942c524d06522ebaf0510a75592a (patch) | |
| tree | 979e3f88bf6e507021c28ac3e9236f7d5cc3bfa9 /drivers/media | |
| parent | 3a9677063f00a61b6067a07df3d7ee12eace79b7 (diff) | |
[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>
Diffstat (limited to 'drivers/media')
| -rw-r--r-- | drivers/media/media-entity.c | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/drivers/media/media-entity.c b/drivers/media/media-entity.c index cb30ffbd5ba8..2c286c307145 100644 --- a/drivers/media/media-entity.c +++ b/drivers/media/media-entity.c @@ -20,6 +20,7 @@ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ +#include <linux/bitmap.h> #include <linux/module.h> #include <linux/slab.h> #include <media/media-entity.h> @@ -121,7 +122,6 @@ static struct media_entity *stack_pop(struct media_entity_graph *graph) return entity; } -#define stack_peek(en) ((en)->stack[(en)->top - 1].entity) #define link_top(en) ((en)->stack[(en)->top].link) #define stack_top(en) ((en)->stack[(en)->top].entity) @@ -140,6 +140,12 @@ void media_entity_graph_walk_start(struct media_entity_graph *graph, { graph->top = 0; graph->stack[graph->top].entity = NULL; + bitmap_zero(graph->entities, MEDIA_ENTITY_ENUM_MAX_ID); + + if (WARN_ON(entity->id >= MEDIA_ENTITY_ENUM_MAX_ID)) + return; + + __set_bit(entity->id, graph->entities); stack_push(graph, entity); } EXPORT_SYMBOL_GPL(media_entity_graph_walk_start); @@ -180,9 +186,11 @@ media_entity_graph_walk_next(struct media_entity_graph *graph) /* Get the entity in the other end of the link . */ next = media_entity_other(entity, link); + if (WARN_ON(next->id >= MEDIA_ENTITY_ENUM_MAX_ID)) + return NULL; - /* Was it the entity we came here from? */ - if (next == stack_peek(graph)) { + /* Has the entity already been visited? */ + if (__test_and_set_bit(next->id, graph->entities)) { link_top(graph)++; continue; } |