Re: [PATCH] media: cedrus: Forbid setting new formats on busy queues

[Hans Verkuil]

On 2/14/19 9:37 AM, Paul Kocialkowski wrote:
> Check that our queues are not busy before setting the format or return
> EBUSY if that's the case. This ensures that our format can't change
> once buffers are allocated for the queue.
> 
> Signed-off-by: Paul Kocialkowski <paul.kocialkowski@xxxxxxxxxxx>
> ---
>  drivers/staging/media/sunxi/cedrus/cedrus_video.c | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
> 
> diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_video.c b/drivers/staging/media/sunxi/cedrus/cedrus_video.c
> index b5cc79389d67..3420a938a613 100644
> --- a/drivers/staging/media/sunxi/cedrus/cedrus_video.c
> +++ b/drivers/staging/media/sunxi/cedrus/cedrus_video.c
> @@ -282,8 +282,15 @@ static int cedrus_s_fmt_vid_cap(struct file *file, void *priv,
>  {
>  	struct cedrus_ctx *ctx = cedrus_file2ctx(file);
>  	struct cedrus_dev *dev = ctx->dev;
> +	struct vb2_queue *vq;
>  	int ret;
>  
> +	vq = v4l2_m2m_get_vq(ctx->fh.m2m_ctx, f->type);
> +	if (!vq)
> +		return -EINVAL;

Can this ever happen?

Regards,

	Hans

> +	else if (vb2_is_busy(vq))
> +		return -EBUSY;
> +
>  	ret = cedrus_try_fmt_vid_cap(file, priv, f);
>  	if (ret)
>  		return ret;
> @@ -299,8 +306,15 @@ static int cedrus_s_fmt_vid_out(struct file *file, void *priv,
>  				struct v4l2_format *f)
>  {
>  	struct cedrus_ctx *ctx = cedrus_file2ctx(file);
> +	struct vb2_queue *vq;
>  	int ret;
>  
> +	vq = v4l2_m2m_get_vq(ctx->fh.m2m_ctx, f->type);
> +	if (!vq)
> +		return -EINVAL;
> +	else if (vb2_is_busy(vq))
> +		return -EBUSY;
> +
>  	ret = cedrus_try_fmt_vid_out(file, priv, f);
>  	if (ret)
>  		return ret;
>