Iterating over the links for an entity is a somewhat common need
through the media subsystem, but generally the assumption is that
they will all be data links. To meet that assumption add a new macro
that iterates through an entity's links and skips non-data links.
Signed-off-by: Daniel Scally <djrscally@xxxxxxxxx>
---
Changes since v1 (suggested by Jacopo and Laurent):
- Simplified __media_entity_next_link()
- Added the link_type param to __media_entity_next_link()
- Moved __media_entity_next_link() to mc-entity.c rather than
media-entity.h
drivers/media/mc/mc-entity.c | 16 ++++++++++++++++
include/media/media-entity.h | 29 +++++++++++++++++++++++++++++
2 files changed, 45 insertions(+)
diff --git a/drivers/media/mc/mc-entity.c b/drivers/media/mc/mc-entity.c
index 11f5207f73aa..a247d5679930 100644
--- a/drivers/media/mc/mc-entity.c
+++ b/drivers/media/mc/mc-entity.c
@@ -9,6 +9,7 @@
*/
#include <linux/bitmap.h>
+#include <linux/list.h>
#include <linux/property.h>
#include <linux/slab.h>
#include <media/media-entity.h>
@@ -1051,3 +1052,18 @@ struct media_link *media_create_ancillary_link(struct media_entity *primary,
return link;
}
EXPORT_SYMBOL_GPL(media_create_ancillary_link);
+
+struct media_link *__media_entity_next_link(struct media_entity *entity,
+ struct media_link *link,
+ unsigned long link_type)
+{
+ link = link ? list_next_entry(link, list)
+ : list_first_entry(&entity->links, typeof(*link), list);
+
+ list_for_each_entry_from(link, &entity->links, list)
+ if ((link->flags & MEDIA_LNK_FL_LINK_TYPE) == link_type)
+ return link;
+
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(__media_entity_next_link);
diff --git a/include/media/media-entity.h b/include/media/media-entity.h
index a9a1c0ec5d1c..903c9368c50d 100644
--- a/include/media/media-entity.h
+++ b/include/media/media-entity.h
@@ -1140,4 +1140,33 @@ struct media_link *
media_create_ancillary_link(struct media_entity *primary,
struct media_entity *ancillary);
+/**
+ * __media_entity_next_link() - iterate through a &media_entity's links,
+ *
+ * @entity: pointer to the &media_entity
+ * @link: pointer to a &media_link to hold the iterated values
+ * @link_type: one of the MEDIA_LNK_FL_LINK_TYPE flags
+ *
+ * Return the next link against an entity matching a specific link type. This
+ * allows iteration through an entity's links whilst guaranteeing all of the
+ * returned links are of the given type.
+ */
+struct media_link *__media_entity_next_link(struct media_entity *entity,
+ struct media_link *link,
+ unsigned long link_type);
+
+/**
+ * for_each_media_entity_data_link() - Iterate through an entity's data links
+ *
+ * @entity: pointer to the &media_entity
+ * @link: pointer to a &media_link to hold the iterated values
+ *
+ * Iterate over a &media_entity's data links
+ */
+#define for_each_media_entity_data_link(entity, link) \
+ for (link = __media_entity_next_link(entity, NULL, \
+ MEDIA_LNK_FL_DATA_LINK); \
+ link; \
+ link = __media_entity_next_link(entity, link, \
+ MEDIA_LNK_FL_DATA_LINK))
#endif
--
2.25.1
