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

[Stefan Wahren]

Am 15.11.23 um 20:31 schrieb Laurent Pinchart:
> 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@xxxxxxxxxxxxxxx>
> > >
> > > 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@xxxxxxxxxxxxxxx>
> > > Signed-off-by: Umang Jain <umang.jain@xxxxxxxxxxxxxxxx>
> > > ---
> > ...
> >
> > > 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 ?
i'm fine with it
> > > + *
> > > + * 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.