Re: [PATCH] media: videobuf2: check constants during build time

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

On 28.03.2025 23:05, Michał Mirosław wrote:
> There is nothing a driver author can do fix in the driver to make the
> global constants match. Since the assertion can be verified at build
> time, don't return EINVAL at runtime for it.
>
> Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
> ---
>   drivers/media/common/videobuf2/videobuf2-v4l2.c | 11 +++++------
>   1 file changed, 5 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/media/common/videobuf2/videobuf2-v4l2.c b/drivers/media/common/videobuf2/videobuf2-v4l2.c
> index 9201d854dbcc..1cd26faee503 100644
> --- a/drivers/media/common/videobuf2/videobuf2-v4l2.c
> +++ b/drivers/media/common/videobuf2/videobuf2-v4l2.c
> @@ -903,6 +903,11 @@ EXPORT_SYMBOL_GPL(vb2_expbuf);
>   
>   int vb2_queue_init_name(struct vb2_queue *q, const char *name)
>   {
> +	/* vb2_memory should match with v4l2_memory */
> +	BUILD_BUG_ON(VB2_MEMORY_MMAP != (int)V4L2_MEMORY_MMAP);
> +	BUILD_BUG_ON(VB2_MEMORY_USERPTR != (int)V4L2_MEMORY_USERPTR);
> +	BUILD_BUG_ON(VB2_MEMORY_DMABUF != (int)V4L2_MEMORY_DMABUF);
> +
>   	/*
>   	 * Sanity check
>   	 */
> @@ -916,12 +921,6 @@ int vb2_queue_init_name(struct vb2_queue *q, const char *name)
>   	WARN_ON((q->timestamp_flags & V4L2_BUF_FLAG_TIMESTAMP_MASK) ==
>   		V4L2_BUF_FLAG_TIMESTAMP_UNKNOWN);
>   
> -	/* Warn that vb2_memory should match with v4l2_memory */
> -	if (WARN_ON(VB2_MEMORY_MMAP != (int)V4L2_MEMORY_MMAP)
> -		|| WARN_ON(VB2_MEMORY_USERPTR != (int)V4L2_MEMORY_USERPTR)
> -		|| WARN_ON(VB2_MEMORY_DMABUF != (int)V4L2_MEMORY_DMABUF))
> -		return -EINVAL;
> -
>   	if (q->buf_struct_size == 0)
>   		q->buf_struct_size = sizeof(struct vb2_v4l2_buffer);
>   

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland