On 08/30/2015 05:06 AM, 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@xxxxxxxxxxxxxxx>
Acked-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>
>
> diff --git a/drivers/media/media-device.c b/drivers/media/media-device.c
> index ec98595b8a7a..5b2c9f7fcd45 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);
>
> diff --git a/drivers/media/media-entity.c b/drivers/media/media-entity.c
> index 192af193a394..c89f51bc688d 100644
> --- a/drivers/media/media-entity.c
> +++ b/drivers/media/media-entity.c
> @@ -174,13 +174,15 @@ 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);
> gobj->id = media_gobj_gen_id(type, ++mdev->intf_devnode_id);
> + list_add_tail(&gobj->list, &mdev->interfaces);
> break;
> }
> dev_dbg_obj(__func__, gobj);
> @@ -195,16 +197,10 @@ void media_gobj_init(struct media_device *mdev,
> */
> void media_gobj_remove(struct media_gobj *gobj)
> {
> + dev_dbg_obj(__func__, 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;
> - }
> -
> - dev_dbg_obj(__func__, gobj);
> + list_del(&gobj->list);
> }
>
> /**
> 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)
>
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