On Thu, Jan 20, 2022 at 02:56:02PM +0100, Christoph Hellwig wrote: > - on the input side to dma mapping the bio_vecs (or phyrs) are chained > as bios or whatever the containing structure is. These already exist > and have infrastructure at least in the block layer > - on the output side I plan for two options: > > 1) we have a sane IOMMU and everyting will be coalesced into a > single dma_range. This requires setting the block layer > merge boundary to match the IOMMU page size, but that is > a very good thing to do anyway.
It doesn't look like IOMMU page sizes are exported, or even necessarily consistently sized on at least one arch (power).
