Re: [PATCH v7 42/44] [media] media-device: add pads and links to media_device

[Hans Verkuil <hverkuil@xs4all.nl>]

On 08/23/15 22:17, Mauro Carvalho Chehab wrote:
> The MC next gen API sends objects to userspace grouped by
> their types.
> 
> In the case of pads and links, in order to improve performance
> and have a simpler code, the best is to store them also on
> separate linked lists at MC.
> 
> If we don't do that, we would need this kind of interaction
> to send data to userspace (code is in structured english):
> 
> 	for each entity:
> 		for each pad:
> 			store pads
> 
> 	for each entity:
> 		for each link:
> 			store link
> 
> 	for each interface:
> 		for each link:
> 			store link
> 
> With would require one nexted loop for pads and two nested
> loops for links. By using  separate linked lists for them,
> just one loop would be enough.
> 
> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

Acked-by: Hans Verkuil <hans.verkuil@cisco.com>

> 
> diff --git a/drivers/media/media-device.c b/drivers/media/media-device.c
> index 01cd014963d6..2de65a621b93 100644
> --- a/drivers/media/media-device.c
> +++ b/drivers/media/media-device.c
> @@ -382,6 +382,8 @@ int __must_check __media_device_register(struct media_device *mdev,
>  
>  	INIT_LIST_HEAD(&mdev->entities);
>  	INIT_LIST_HEAD(&mdev->interfaces);
> +	INIT_LIST_HEAD(&mdev->pads);
> +	INIT_LIST_HEAD(&mdev->links);
>  	spin_lock_init(&mdev->lock);
>  	mutex_init(&mdev->graph_mutex);
>  
> @@ -474,7 +476,6 @@ void media_device_unregister_entity(struct media_entity *entity)
>  	spin_lock(&mdev->lock);
>  	list_for_each_entry_safe(link, tmp, &entity->links, graph_obj.list) {
>  		media_gobj_remove(&link->graph_obj);
> -		list_del(&link->list);
>  		kfree(link);
>  	}
>  	for (i = 0; i < entity->num_pads; i++)
> diff --git a/drivers/media/media-entity.c b/drivers/media/media-entity.c
> index 17f2f7555d42..ef26c01a5a9a 100644
> --- a/drivers/media/media-entity.c
> +++ b/drivers/media/media-entity.c
> @@ -172,9 +172,11 @@ void media_gobj_init(struct media_device *mdev,
>  		break;
>  	case MEDIA_GRAPH_PAD:
>  		gobj->id = media_gobj_gen_id(type, ++mdev->pad_id);
> +		list_add_tail(&gobj->list, &mdev->pads);
>  		break;
>  	case MEDIA_GRAPH_LINK:
>  		gobj->id = media_gobj_gen_id(type, ++mdev->link_id);
> +		list_add_tail(&gobj->list, &mdev->links);
>  		break;
>  	case MEDIA_GRAPH_INTF_DEVNODE:
>  		list_add_tail(&gobj->list, &mdev->interfaces);
> @@ -194,13 +196,7 @@ void media_gobj_init(struct media_device *mdev,
>  void media_gobj_remove(struct media_gobj *gobj)
>  {
>  	/* Remove the object from mdev list */
> -	switch (media_type(gobj)) {
> -	case MEDIA_GRAPH_ENTITY:
> -	case MEDIA_GRAPH_INTF_DEVNODE:
> -		list_del(&gobj->list);
> -	default:
> -		break;
> -	}
> +	list_del(&gobj->list);
>  
>  	dev_dbg_obj(__func__, gobj);
>  }
> diff --git a/include/media/media-device.h b/include/media/media-device.h
> index 85fa302047bd..0d1b9c687454 100644
> --- a/include/media/media-device.h
> +++ b/include/media/media-device.h
> @@ -47,6 +47,8 @@ struct device;
>   * @intf_devnode_id: Unique ID used on the last interface devnode registered
>   * @entities:	List of registered entities
>   * @interfaces:	List of registered interfaces
> + * @pads:	List of registered pads
> + * @links:	List of registered links
>   * @lock:	Entities list lock
>   * @graph_mutex: Entities graph operation lock
>   * @link_notify: Link state change notification callback
> @@ -79,6 +81,8 @@ struct media_device {
>  
>  	struct list_head entities;
>  	struct list_head interfaces;
> +	struct list_head pads;
> +	struct list_head links;
>  
>  	/* Protects the entities list */
>  	spinlock_t lock;
> @@ -117,6 +121,14 @@ struct media_device *media_device_find_devres(struct device *dev);
>  #define media_device_for_each_intf(intf, mdev)			\
>  	list_for_each_entry(intf, &(mdev)->interfaces, graph_obj.list)
>  
> +/* Iterate over all pads. */
> +#define media_device_for_each_pad(pad, mdev)			\
> +	list_for_each_entry(pad, &(mdev)->pads, graph_obj.list)
> +
> +/* Iterate over all links. */
> +#define media_device_for_each_link(link, mdev)			\
> +	list_for_each_entry(link, &(mdev)->links, graph_obj.list)
> +
>  
>  #else
>  static inline int media_device_register(struct media_device *mdev)
>