On 04/05/2020 11:26, Laurent Pinchart wrote:
> 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>
> ---
> .../media/common/videobuf2/videobuf2-core.c | 21 ++++++++++++++++---
> include/media/videobuf2-core.h | 15 +++++++++++++
> 2 files changed, 33 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c
> index 44d65f5be845..befdc89983e2 100644
> --- a/drivers/media/common/videobuf2/videobuf2-core.c
> +++ b/drivers/media/common/videobuf2/videobuf2-core.c
> @@ -2073,12 +2073,12 @@ static int __find_plane_by_offset(struct vb2_queue *q, unsigned long off,
> return -EINVAL;
> }
>
> -int vb2_core_expbuf(struct vb2_queue *q, int *fd, unsigned int type,
> - unsigned int index, unsigned int plane, unsigned int flags)
> +int vb2_core_expbuf_dmabuf(struct vb2_queue *q, unsigned int type,
> + unsigned int index, unsigned int plane,
> + unsigned int flags, struct dma_buf **dmabuf)
Just returning struct dma_buf and using ERR_PTR() to report errors would
be much more elegant.
Otherwise this patch is fine.
Regards,
Hans
> {
> struct vb2_buffer *vb = NULL;
> struct vb2_plane *vb_plane;
> - int ret;
> struct dma_buf *dbuf;
>
> if (q->memory != VB2_MEMORY_MMAP) {
> @@ -2128,6 +2128,21 @@ int vb2_core_expbuf(struct vb2_queue *q, int *fd, unsigned int type,
> return -EINVAL;
> }
>
> + *dmabuf = dbuf;
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(vb2_core_expbuf_dmabuf);
> +
> +int vb2_core_expbuf(struct vb2_queue *q, int *fd, unsigned int type,
> + unsigned int index, unsigned int plane, unsigned int flags)
> +{
> + struct dma_buf *dbuf;
> + int ret;
> +
> + ret = vb2_core_expbuf_dmabuf(q, type, index, plane, flags, &dbuf);
> + if (ret)
> + return ret;
> +
> ret = dma_buf_fd(dbuf, flags & ~O_ACCMODE);
> if (ret < 0) {
> dprintk(3, "buffer %d, plane %d failed to export (%d)\n",
> diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
> index f11b96514cf7..86920d3264ab 100644
> --- a/include/media/videobuf2-core.h
> +++ b/include/media/videobuf2-core.h
> @@ -875,6 +875,21 @@ 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
> + * @dmabuf: Returns the dmabuf pointer
> + *
> + */
> +int vb2_core_expbuf_dmabuf(struct vb2_queue *q, unsigned int type,
> + unsigned int index, unsigned int plane,
> + unsigned int flags, struct dma_buf **dmabuf);
> +
> /**
> * vb2_core_expbuf() - Export a buffer as a file descriptor.
> * @q: pointer to &struct vb2_queue with videobuf2 queue.
>
