Re: [PATCH v2 04/15] docs: dma-api: document DMA_ATTR_CPU_CACHE_CLEAN

Petr Tesarik
2026-01-05T09:52:02Z

On Mon, 5 Jan 2026 03:23:05 -0500
"Michael S. Tsirkin" <mst@redhat.com> wrote:

> Document DMA_ATTR_CPU_CACHE_CLEAN as implemented in the
> previous patch.
>
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

LGTM. I'm not formally a reviewer, but FWIW:

Reviewed-by: Petr Tesarik <ptesarik@suse.com>

> ---
> Documentation/core-api/dma-attributes.rst | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/Documentation/core-api/dma-attributes.rst b/Documentation/core-api/dma-attributes.rst
> index 0bdc2be65e57..1d7bfad73b1c 100644
> --- a/Documentation/core-api/dma-attributes.rst
> +++ b/Documentation/core-api/dma-attributes.rst
> @@ -148,3 +148,12 @@ DMA_ATTR_MMIO is appropriate.
> For architectures that require cache flushing for DMA coherence
> DMA_ATTR_MMIO will not perform any cache flushing. The address
> provided must never be mapped cacheable into the CPU.
> +
> +DMA_ATTR_CPU_CACHE_CLEAN
> +------------------------
> +
> +This attribute indicates the CPU will not dirty any cacheline overlapping this
> +DMA_FROM_DEVICE/DMA_BIDIRECTIONAL buffer while it is mapped. This allows
> +multiple small buffers to safely share a cacheline without risk of data
> +corruption, suppressing DMA debug warnings about overlapping mappings.
> +All mappings sharing a cacheline should have this attribute.