Re: [PATCH v3 22/33] omap3isp: Assume media_entity_pipeline_start may fail

Laurent Pinchart
2012-02-22T10:48:34Z

Hi Sakari,

Thanks for the patch.

On Monday 20 February 2012 03:57:01 Sakari Ailus wrote:
> Since media_entity_pipeline_start() now does link validation, it may
> actually fail. Perform the error handling.
>
> Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
> ---
> drivers/media/video/omap3isp/ispvideo.c | 20 ++++++++++++--------
> 1 files changed, 12 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/media/video/omap3isp/ispvideo.c
> b/drivers/media/video/omap3isp/ispvideo.c index c191f13..17522db 100644
> --- a/drivers/media/video/omap3isp/ispvideo.c
> +++ b/drivers/media/video/omap3isp/ispvideo.c
> @@ -993,14 +993,16 @@ isp_video_streamon(struct file *file, void *fh, enum
> v4l2_buf_type type) */
> pipe = video->video.entity.pipe
> ? to_isp_pipeline(&video->video.entity) : &video->pipe;
> - media_entity_pipeline_start(&video->video.entity, &pipe->pipe);
> + ret = media_entity_pipeline_start(&video->video.entity, &pipe->pipe);
> + if (ret < 0)
> + goto err_media_entity_pipeline_start;
>
> /* Verify that the currently configured format matches the output of
> * the connected subdev.
> */
> ret = isp_video_check_format(video, vfh);
> if (ret < 0)
> - goto error;
> + goto err_isp_video_check_format;
>
> video->bpl_padding = ret;
> video->bpl_value = vfh->format.fmt.pix.bytesperline;
> @@ -1017,7 +1019,7 @@ isp_video_streamon(struct file *file, void *fh, enum
> v4l2_buf_type type) } else {
> if (far_end == NULL) {
> ret = -EPIPE;
> - goto error;
> + goto err_isp_video_check_format;
> }
>
> state = ISP_PIPELINE_STREAM_INPUT | ISP_PIPELINE_IDLE_INPUT;
> @@ -1032,7 +1034,7 @@ isp_video_streamon(struct file *file, void *fh, enum
> v4l2_buf_type type) /* Validate the pipeline and update its state. */
> ret = isp_video_validate_pipeline(pipe);
> if (ret < 0)
> - goto error;
> + goto err_isp_video_check_format;
>
> pipe->error = false;
>
> @@ -1054,7 +1056,7 @@ isp_video_streamon(struct file *file, void *fh, enum
> v4l2_buf_type type)
>
> ret = omap3isp_video_queue_streamon(&vfh->queue);
> if (ret < 0)
> - goto error;
> + goto err_isp_video_check_format;
>
> /* In sensor-to-memory mode, the stream can be started synchronously
> * to the stream on command. In memory-to-memory mode, it will be
> @@ -1064,19 +1066,21 @@ isp_video_streamon(struct file *file, void *fh, enum
> v4l2_buf_type type) ret = omap3isp_pipeline_set_stream(pipe,
> ISP_PIPELINE_STREAM_CONTINUOUS);
> if (ret < 0)
> - goto error;
> + goto err_omap3isp_set_stream;
> spin_lock_irqsave(&video->queue->irqlock, flags);
> if (list_empty(&video->dmaqueue))
> video->dmaqueue_flags |= ISP_VIDEO_DMAQUEUE_UNDERRUN;
> spin_unlock_irqrestore(&video->queue->irqlock, flags);
> }
>
> -error:
> if (ret < 0) {
> +err_omap3isp_set_stream:
> omap3isp_video_queue_streamoff(&vfh->queue);
> +err_isp_video_check_format:
> + media_entity_pipeline_stop(&video->video.entity);
> +err_media_entity_pipeline_start:
> if (video->isp->pdata->set_constraints)
> video->isp->pdata->set_constraints(video->isp, false);
> - media_entity_pipeline_stop(&video->video.entity);
> /* The DMA queue must be emptied here, otherwise CCDC interrupts
> * that will get triggered the next time the CCDC is powered up
> * will try to access buffers that might have been freed but

As you add error labels, you can remove the if (ret < 0) test and move error
handling to a separate block. set_constraint() should be called before
media_entity_pipeline_stop() in that case. Another option is to leave error
handling untouched, and to return directly when media_entity_pipeline_start()
fails (after unlocking the mutex of course).

--
Regards,

Laurent Pinchart