Re: [PATCH] media: entity: Catch unbalanced media_pipeline_stop calls

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Kieran,

Thank you for the patch.

On Tuesday 03 Jan 2017 13:12:11 Kieran Bingham wrote:
> Drivers must not perform unbalanced calls to stop the entity pipeline,
> however if they do they will fault in the core media code, as the
> entity->pipe will be set as NULL. We handle this gracefully in the core
> with a WARN for the developer.
> 
> Replace the erroneous check on zero streaming counts, with a check on
> NULL pipe elements instead, as this is the symptom of unbalanced
> media_pipeline_stop calls.
> 
> Signed-off-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>

This looks good to me,

Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

I'll let Sakari review and merge the patch.

> ---
>  drivers/media/media-entity.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/media/media-entity.c b/drivers/media/media-entity.c
> index caa13e6f09f5..cb1fb2c17f85 100644
> --- a/drivers/media/media-entity.c
> +++ b/drivers/media/media-entity.c
> @@ -534,8 +534,13 @@ void __media_pipeline_stop(struct media_entity *entity)
> struct media_graph *graph = &entity->pipe->graph;
>  	struct media_pipeline *pipe = entity->pipe;
> 
> +	/*
> +	 * If the following check fails, the driver has performed an
> +	 * unbalanced call to media_pipeline_stop()
> +	 */
> +	if (WARN_ON(!pipe))
> +		return;
> 
> -	WARN_ON(!pipe->streaming_count);
>  	media_graph_walk_start(graph, entity);
> 
>  	while ((entity = media_graph_walk_next(graph))) {

-- 
Regards,

Laurent Pinchart