Re: [PATCH 3/4] dma-buf: begin/end_cpu might lock the dma_resv lock

["Christian König" <christian.koenig@amd.com>]

Am 11.12.20 um 16:58 schrieb Daniel Vetter:
> At least amdgpu and i915 do, so lets just document this as the rule.
>
> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> Cc: Thomas Zimmermann <tzimmermann@suse.de>
> Cc: Sumit Semwal <sumit.semwal@linaro.org>
> Cc: "Christian König" <christian.koenig@amd.com>
> Cc: linux-media@vger.kernel.org
> Cc: linaro-mm-sig@lists.linaro.org

Reviewed-by: Christian König <christian.koenig@amd.com>

> ---
>   drivers/dma-buf/dma-buf.c | 4 ++++
>   1 file changed, 4 insertions(+)
>
> diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
> index e1fa6c6f02c4..00d5afe904cc 100644
> --- a/drivers/dma-buf/dma-buf.c
> +++ b/drivers/dma-buf/dma-buf.c
> @@ -1118,6 +1118,8 @@ int dma_buf_begin_cpu_access(struct dma_buf *dmabuf,
>   	if (WARN_ON(!dmabuf))
>   		return -EINVAL;
>   
> +	might_lock(&dma_buf->resv.lock);
> +
>   	if (dmabuf->ops->begin_cpu_access)
>   		ret = dmabuf->ops->begin_cpu_access(dmabuf, direction);
>   
> @@ -1151,6 +1153,8 @@ int dma_buf_end_cpu_access(struct dma_buf *dmabuf,
>   
>   	WARN_ON(!dmabuf);
>   
> +	might_lock(&dma_buf->resv.lock);
> +
>   	if (dmabuf->ops->end_cpu_access)
>   		ret = dmabuf->ops->end_cpu_access(dmabuf, direction);
>