[PATCH RFC v2 1/3] media: added managed media entity initialization

[Andrzej Hajda <a.hajda@xxxxxxxxxxx>]

This patch adds managed versions of initialization
and cleanup functions for media entity.

Signed-off-by: Andrzej Hajda <a.hajda@xxxxxxxxxxx>
Reviewed-by: Sylwester Nawrocki <s.nawrocki@xxxxxxxxxxx>
Signed-off-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
---
v2:
	- added missing struct device forward declaration
---
 drivers/media/media-entity.c |   70 ++++++++++++++++++++++++++++++++++++++++++
 include/media/media-entity.h |    6 ++++
 2 files changed, 76 insertions(+)

diff --git a/drivers/media/media-entity.c b/drivers/media/media-entity.c
index e1cd132..696de35 100644
--- a/drivers/media/media-entity.c
+++ b/drivers/media/media-entity.c
@@ -82,9 +82,79 @@ void
 media_entity_cleanup(struct media_entity *entity)
 {
 	kfree(entity->links);
+	entity->links = NULL;
 }
 EXPORT_SYMBOL_GPL(media_entity_cleanup);
 
+static void devm_media_entity_release(struct device *dev, void *res)
+{
+	struct media_entity **entity = res;
+
+	media_entity_cleanup(*entity);
+}
+
+/**
+ * devm_media_entity_init - managed media entity initialization
+ *
+ * @dev: Device for which @entity belongs to.
+ * @entity: Entity to be initialized.
+ * @num_pads: Total number of sink and source pads.
+ * @pads: Array of 'num_pads' pads.
+ * @extra_links: Initial estimate of the number of extra links.
+ *
+ * This is a managed version of media_entity_init. Entity initialized with
+ * this function will be automatically cleaned up on driver detach.
+ *
+ * If an entity initialized with this function needs to be cleaned up
+ * separately, devm_media_entity_cleanup() must be used.
+ */
+int
+devm_media_entity_init(struct device *dev, struct media_entity *entity,
+		       u16 num_pads, struct media_pad *pads, u16 extra_links)
+{
+	struct media_entity **dr;
+	int rc;
+
+	dr = devres_alloc(devm_media_entity_release, sizeof(*dr), GFP_KERNEL);
+	if (!dr)
+		return -ENOMEM;
+
+	rc = media_entity_init(entity, num_pads, pads, extra_links);
+	if (rc) {
+		devres_free(dr);
+		return rc;
+	}
+
+	*dr = entity;
+	devres_add(dev, dr);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(devm_media_entity_init);
+
+static int devm_media_entity_match(struct device *dev, void *res, void *data)
+{
+	struct media_entity **this = res, **entity = data;
+
+	return *this == *entity;
+}
+
+/**
+ * devm_media_entity_cleanup - managed media entity cleanup
+ *
+ * @dev: Device for which @entity belongs to.
+ * @entity: Entity to be cleaned up.
+ *
+ * This function should be used to manual cleanup of an media entity
+ * initialized with devm_media_entity_init().
+ */
+void devm_media_entity_cleanup(struct device *dev, struct media_entity *entity)
+{
+	WARN_ON(devres_release(dev, devm_media_entity_release,
+			       devm_media_entity_match, &entity));
+}
+EXPORT_SYMBOL_GPL(devm_media_entity_cleanup);
+
 /* -----------------------------------------------------------------------------
  * Graph traversal
  */
diff --git a/include/media/media-entity.h b/include/media/media-entity.h
index 0c16f51..e3f1604 100644
--- a/include/media/media-entity.h
+++ b/include/media/media-entity.h
@@ -26,6 +26,8 @@
 #include <linux/list.h>
 #include <linux/media.h>
 
+struct device;
+
 struct media_pipeline {
 };
 
@@ -126,6 +128,10 @@ int media_entity_init(struct media_entity *entity, u16 num_pads,
 		struct media_pad *pads, u16 extra_links);
 void media_entity_cleanup(struct media_entity *entity);
 
+int devm_media_entity_init(struct device *dev, struct media_entity *entity,
+		u16 num_pads, struct media_pad *pads, u16 extra_links);
+void devm_media_entity_cleanup(struct device *dev, struct media_entity *entity);
+
 int media_entity_create_link(struct media_entity *source, u16 source_pad,
 		struct media_entity *sink, u16 sink_pad, u32 flags);
 int __media_entity_setup_link(struct media_link *link, u32 flags);
-- 
1.7.10.4

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