RE: [PATCH] videobuf2: call buf_finish() on unprocessed buffers

[Marek Szyprowski <m.szyprowski@samsung.com>]

Hello,

On Thursday, July 14, 2011 11:10 PM Jonathan Corbet wrote:

> When user space stops streaming, there may be buffers which have been given
> to buf_prepare() and which may or may not have been passed to buf_queue().
> The videobuf2 core simply takes those buffers back; if buf_prepare() does
> work that needs cleaning up (like setting up a DMA mapping), that cleanup
> will not happen.
> 
> This patch establishes a simple contract with drivers: buffers given to
> buf_prepare() will eventually see a buf_finish() call.
> 
> Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>

> ---
>  drivers/media/video/videobuf2-core.c |    8 +++++++-
>  1 files changed, 7 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/media/video/videobuf2-core.c
> b/drivers/media/video/videobuf2-core.c
> index 6ba1461..2ba08ab 100644
> --- a/drivers/media/video/videobuf2-core.c
> +++ b/drivers/media/video/videobuf2-core.c
> @@ -1177,6 +1177,7 @@ EXPORT_SYMBOL_GPL(vb2_streamon);
>   */
>  static void __vb2_queue_cancel(struct vb2_queue *q)
>  {
> +	struct vb2_buffer *vb;
>  	unsigned int i;
> 
>  	/*
> @@ -1188,13 +1189,18 @@ static void __vb2_queue_cancel(struct vb2_queue *q)
>  	q->streaming = 0;
> 
>  	/*
> -	 * Remove all buffers from videobuf's list...
> +	 * Remove all buffers from videobuf's list...  Give the driver
> +	 * a chance to clean them up first, though.
>  	 */
> +	list_for_each_entry(vb, &q->queued_list, queued_entry)
> +		call_qop(q, buf_finish, vb);
>  	INIT_LIST_HEAD(&q->queued_list);
>  	/*
>  	 * ...and done list; userspace will not receive any buffers it
>  	 * has not already dequeued before initiating cancel.
>  	 */
> +	list_for_each_entry(vb, &q->done_list, done_entry)
> +		call_qop(q, buf_finish, vb);
>  	INIT_LIST_HEAD(&q->done_list);
>  	wake_up_all(&q->done_wq);
> 
> --
> 1.7.6

Best regards
-- 
Marek Szyprowski
Samsung Poland R&D Center