Btw, given that I assume this is 4.20 material now, any chance we could merge it through the dma-mapping tree? I have some major changes pending that would clash if done in a different tree, so I'd rather get it all together. > We check this flag in arch_dma_alloc (which are used in non-coherent case) to > skip MMU mapping if we are advertised that consistency is not required. > > So, actually we can get rid of this flag checking in arch_dma_alloc and > simply always do MMU mapping to enforce non-cachability and return > non-cacheable memory even if DMA_ATTR_NON_CONSISTENT is passed. > But I don't sure we want to do that. I plan to kill this flag for 4.20 (or 4.20 at latest) in favor of a better interface. But your implementation looks ok, so I'm fine with keeping it for now.