On Tue, May 29, 2018 at 03:59:18PM +0200, Gerd Hoffmann wrote:
> So drivers don't need dummy functions just returning NULL.
>
> Cc: Daniel Vetter <daniel@xxxxxxxx>
> Signed-off-by: Gerd Hoffmann <kraxel@xxxxxxxxxx>
Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
Please push to drm-misc-next (maybe after a few more days of waiting for
feedback).
-Daniel
> ---
> include/linux/dma-buf.h | 4 ++--
> drivers/dma-buf/dma-buf.c | 4 ++++
> 2 files changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h
> index 085db2fee2..88917fa796 100644
> --- a/include/linux/dma-buf.h
> +++ b/include/linux/dma-buf.h
> @@ -39,12 +39,12 @@ struct dma_buf_attachment;
>
> /**
> * struct dma_buf_ops - operations possible on struct dma_buf
> - * @map_atomic: maps a page from the buffer into kernel address
> + * @map_atomic: [optional] maps a page from the buffer into kernel address
> * space, users may not block until the subsequent unmap call.
> * This callback must not sleep.
> * @unmap_atomic: [optional] unmaps a atomically mapped page from the buffer.
> * This Callback must not sleep.
> - * @map: maps a page from the buffer into kernel address space.
> + * @map: [optional] maps a page from the buffer into kernel address space.
> * @unmap: [optional] unmaps a page from the buffer.
> * @vmap: [optional] creates a virtual mapping for the buffer into kernel
> * address space. Same restrictions as for vmap and friends apply.
> diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
> index d78d5fc173..4c45e31258 100644
> --- a/drivers/dma-buf/dma-buf.c
> +++ b/drivers/dma-buf/dma-buf.c
> @@ -872,6 +872,8 @@ void *dma_buf_kmap_atomic(struct dma_buf *dmabuf, unsigned long page_num)
> {
> WARN_ON(!dmabuf);
>
> + if (!dmabuf->ops->map_atomic)
> + return NULL;
> return dmabuf->ops->map_atomic(dmabuf, page_num);
> }
> EXPORT_SYMBOL_GPL(dma_buf_kmap_atomic);
> @@ -907,6 +909,8 @@ void *dma_buf_kmap(struct dma_buf *dmabuf, unsigned long page_num)
> {
> WARN_ON(!dmabuf);
>
> + if (!dmabuf->ops->map)
> + return NULL;
> return dmabuf->ops->map(dmabuf, page_num);
> }
> EXPORT_SYMBOL_GPL(dma_buf_kmap);
> --
> 2.9.3
>
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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