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

Stefan Wahren
2023-11-15T21:01:37Z

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@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 ?
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.