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

Laurent Pinchart
2023-11-15T19:31:34Z

On Tue, Nov 14, 2023 at 08:41:11PM +0100, Stefan Wahren wrote:
> 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

Would "newly created dmabuf file handle" be clearer and work for
everybody ?

> > + *
> > + * 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.

--
Regards,

Laurent Pinchart