[media] media: Introduce internal index for media entities

The internal index can be used internally by the framework in order to keep
track of entities for a purpose or another. The internal index is constant
while it's registered to a media device, but the same index may be re-used
once the entity having that index is unregistered.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

1 files changed, 17 insertions, 0 deletions

diff --git a/drivers/media/media-device.c b/drivers/media/media-device.c
index 30e3354d7481..ce97f8f196f3 100644
--- a/drivers/media/media-device.c
+++ b/drivers/media/media-device.c
@@ -22,6 +22,7 @@
 
 #include <linux/compat.h>
 #include <linux/export.h>
+#include <linux/idr.h>
 #include <linux/ioctl.h>
 #include <linux/media.h>
 #include <linux/slab.h>
@@ -551,6 +552,17 @@ int __must_check media_device_register_entity(struct media_device *mdev,
 	entity->num_backlinks = 0;
 
 	spin_lock(&mdev->lock);
+
+	entity->internal_idx = ida_simple_get(&mdev->entity_internal_idx, 1, 0,
+					      GFP_KERNEL);
+	if (entity->internal_idx < 0) {
+		spin_unlock(&mdev->lock);
+		return entity->internal_idx;
+	}
+
+	mdev->entity_internal_idx_max =
+		max(mdev->entity_internal_idx_max, entity->internal_idx);
+
 	/* Initialize media_gobj embedded at the entity */
 	media_gobj_create(mdev, MEDIA_GRAPH_ENTITY, &entity->graph_obj);
 
@@ -579,6 +591,8 @@ static void __media_device_unregister_entity(struct media_entity *entity)
 	struct media_interface *intf;
 	unsigned int i;
 
+	ida_simple_remove(&mdev->entity_internal_idx, entity->internal_idx);
+
 	/* Remove all interface links pointing to this entity */
 	list_for_each_entry(intf, &mdev->interfaces, graph_obj.list) {
 		list_for_each_entry_safe(link, tmp, &intf->links, list) {
@@ -632,6 +646,7 @@ void media_device_init(struct media_device *mdev)
 	INIT_LIST_HEAD(&mdev->links);
 	spin_lock_init(&mdev->lock);
 	mutex_init(&mdev->graph_mutex);
+	ida_init(&mdev->entity_internal_idx);
 
 	dev_dbg(mdev->dev, "Media device initialized\n");
 }
@@ -644,6 +659,8 @@ EXPORT_SYMBOL_GPL(media_device_init);
  */
 void media_device_cleanup(struct media_device *mdev)
 {
+	ida_destroy(&mdev->entity_internal_idx);
+	mdev->entity_internal_idx_max = 0;
 	mutex_destroy(&mdev->graph_mutex);
 }
 EXPORT_SYMBOL_GPL(media_device_cleanup);