From: Michael S. Tsirkin Date: Mon, 29 Dec 2025 13:11:41 +0000 (-0500) Subject: docs: dma-api: document DMA_ATTR_CPU_CACHE_CLEAN X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e21dd666e4af829c6a26d830cca8bf4839878297;p=thirdparty%2Flinux.git docs: dma-api: document DMA_ATTR_CPU_CACHE_CLEAN Document DMA_ATTR_CPU_CACHE_CLEAN as implemented in the previous patch. Message-ID: <0720b4be31c1b7a38edca67fd0c97983d2a56936.1767601130.git.mst@redhat.com> Reviewed-by: Petr Tesarik Acked-by: Marek Szyprowski Signed-off-by: Michael S. Tsirkin --- diff --git a/Documentation/core-api/dma-attributes.rst b/Documentation/core-api/dma-attributes.rst index 0bdc2be65e575..1d7bfad73b1c7 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.