Re: [PATCH 1/5] media: vb2: Introduce a vb2_get_buffer accessor

[Boris Brezillon <boris.brezillon@collabora.com>]

On Thu,  6 Jun 2019 12:44:22 -0300
Ezequiel Garcia <ezequiel@collabora.com> wrote:

> Some drivers need to access a vb2 buffer from its
> queue index. Introduce an accessor to abstract this,
> and avoid drivers from accessing private members.
> 
> Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
> ---
>  include/media/videobuf2-core.h | 18 ++++++++++++++++++
>  1 file changed, 18 insertions(+)
> 
> diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
> index c03ef7cc5071..7b1729320b16 100644
> --- a/include/media/videobuf2-core.h
> +++ b/include/media/videobuf2-core.h
> @@ -1163,6 +1163,24 @@ static inline void vb2_clear_last_buffer_dequeued(struct vb2_queue *q)
>  	q->last_buffer_dequeued = false;
>  }
>  
> +/**
> + * vb2_get_buffer() - get a buffer from a queue
> + * @q:		pointer to &struct vb2_queue with videobuf2 queue.
> + * @index:	buffer index
> + *
> + * This function obtains a buffer from a queue, by its index.
> + * Keep in mind that there is no refcounting involved in this
> + * operation, so the buffer lifetime should be taken into
> + * consideration.
> + */
> +static inline struct vb2_buffer *vb2_get_buffer(struct vb2_queue *q,
> +						unsigned int index)
> +{
> +	if (q->num_buffers > 0 && index < q->num_buffers)

No need to check q->num_buffers > 0 because in that case
index < q->num_buffers is always false.

Looks good otherwise

Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>

> +		return q->bufs[index];
> +	return NULL;
> +}
> +
>  /*
>   * The following functions are not part of the vb2 core API, but are useful
>   * functions for videobuf2-*.