[PATCH v3 03/13] iommu/dma: Force bouncing of the size is not cacheline-aligned

[Christoph Hellwig]

On Mon, Nov 07, 2022 at 10:54:36AM +0000, Catalin Marinas wrote:
> An idea: we could add another member to struct scatterlist to track the
> bounced address. We can then do the bouncing in a similar way to
> iommu_dma_map_sg_swiotlb() but without the iova allocation. The latter
> would be a common path for both the bounced and non-bounced cases.

That would be a pretty massive memory overhead for an unusual case,
so I'd rather avoid it.  In addition to the long term plan of doing
DMA mappings without a scatterlist..