Re: [PATCH v2 03/15] media: videobuf2: Allow exporting of a struct dmabuf

Stefan Wahren
2023-11-14T19:41:40Z

Hi Umang,

Am 09.11.23 um 22:02 schrieb Umang Jain:
> From: Dave Stevenson <dave.stevenson@raspberrypi.org>
>
> videobuf2 only allowed exporting a dmabuf as a file descriptor,
> but there are instances where having the struct dma_buf is
> useful within the kernel.
>
> Split the current implementation into two, one step which
> exports a struct dma_buf, and the second which converts that
> into an fd.
>
> Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.org>
> Signed-off-by: Umang Jain <umang.jain@ideasonboard.com>
> ---

...

> diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
> index 4b6a9d2ea372..cba4e495f6a2 100644
> --- a/include/media/videobuf2-core.h
> +++ b/include/media/videobuf2-core.h
> @@ -925,6 +925,21 @@ int vb2_core_streamon(struct vb2_queue *q, unsigned int type);
> */
> int vb2_core_streamoff(struct vb2_queue *q, unsigned int type);
>
> +/**
> + * vb2_core_expbuf_dmabuf() - Export a buffer as a dma_buf structure
> + * @q: videobuf2 queue
> + * @type: buffer type
> + * @index: id number of the buffer
> + * @plane: index of the plane to be exported, 0 for single plane queues
> + * @flags: flags for newly created file, currently only O_CLOEXEC is
> + * supported, refer to manual of open syscall for more details

i think "newly created file" could be confusing here

> + *
> + * Return: Returns the dmabuf pointer
> + */
> +struct dma_buf *vb2_core_expbuf_dmabuf(struct vb2_queue *q, unsigned int type,
> + unsigned int index, unsigned int plane,
> + unsigned int flags);
> +
> /**
> * vb2_core_expbuf() - Export a buffer as a file descriptor.
> * @q: pointer to &struct vb2_queue with videobuf2 queue.