On Wed, Apr 25, 2018 at 07:15:37AM +0200, Christoph Hellwig wrote:
> Only mips and unicore32 select CONFIG_NEED_SG_DMA_LENGTH when building
> swiotlb.  swiotlb itself never merges segements and doesn't accesses the
> dma_length field directly, so drop the dependency.

Is that at odds with Documentation/DMA-API-HOWTO.txt, which seems to
suggest arch ports should enable it for IOMMUs?

Cheers
James