diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/media/media-device.c | 1 | ||||
| -rw-r--r-- | drivers/media/media-entity.c | 46 |
2 files changed, 47 insertions, 0 deletions
diff --git a/drivers/media/media-device.c b/drivers/media/media-device.c index a36509a1df09..d2bc809d7a2a 100644 --- a/drivers/media/media-device.c +++ b/drivers/media/media-device.c @@ -73,6 +73,7 @@ int __must_check media_device_register(struct media_device *mdev) mdev->entity_id = 1; INIT_LIST_HEAD(&mdev->entities); spin_lock_init(&mdev->lock); + mutex_init(&mdev->graph_mutex); /* Register the device node. */ mdev->devnode.fops = &media_device_fops; diff --git a/drivers/media/media-entity.c b/drivers/media/media-entity.c index 166f2b5505ce..3e7e2d569cec 100644 --- a/drivers/media/media-entity.c +++ b/drivers/media/media-entity.c @@ -23,6 +23,7 @@ #include <linux/module.h> #include <linux/slab.h> #include <media/media-entity.h> +#include <media/media-device.h> /** * media_entity_init - Initialize a media entity @@ -196,6 +197,51 @@ media_entity_graph_walk_next(struct media_entity_graph *graph) EXPORT_SYMBOL_GPL(media_entity_graph_walk_next); /* ----------------------------------------------------------------------------- + * Module use count + */ + +/* + * media_entity_get - Get a reference to the parent module + * @entity: The entity + * + * Get a reference to the parent media device module. + * + * The function will return immediately if @entity is NULL. + * + * Return a pointer to the entity on success or NULL on failure. + */ +struct media_entity *media_entity_get(struct media_entity *entity) +{ + if (entity == NULL) + return NULL; + + if (entity->parent->dev && + !try_module_get(entity->parent->dev->driver->owner)) + return NULL; + + return entity; +} +EXPORT_SYMBOL_GPL(media_entity_get); + +/* + * media_entity_put - Release the reference to the parent module + * @entity: The entity + * + * Release the reference count acquired by media_entity_get(). + * + * The function will return immediately if @entity is NULL. + */ +void media_entity_put(struct media_entity *entity) +{ + if (entity == NULL) + return; + + if (entity->parent->dev) + module_put(entity->parent->dev->driver->owner); +} +EXPORT_SYMBOL_GPL(media_entity_put); + +/* ----------------------------------------------------------------------------- * Links management */ |