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| author | Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> | 2013-06-07 17:45:11 +0200 |
|---|---|---|
| committer | Mauro Carvalho Chehab <m.chehab@samsung.com> | 2013-08-18 12:16:48 +0200 |
| commit | 5c7b25b90d36942c524d06522ebaf0510a75592a (patch) | |
| tree | 979e3f88bf6e507021c28ac3e9236f7d5cc3bfa9 | |
| parent | [media] s5p-mfc: Add support for VP8 encoder (diff) | |
| download | linux-5c7b25b90d36942c524d06522ebaf0510a75592a.tar.xz linux-5c7b25b90d36942c524d06522ebaf0510a75592a.zip | |
[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>
| -rw-r--r-- | drivers/media/media-entity.c | 14 | ||||
| -rw-r--r-- | include/media/media-entity.h | 4 |
2 files changed, 15 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; } diff --git a/include/media/media-entity.h b/include/media/media-entity.h index 06bacf937d61..10df55187981 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 @@ static inline u32 media_entity_subtype(struct media_entity *entity) } #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; }; |