On Sun, 2017-04-16 at 10:47 -0600, Logan Gunthorpe wrote: > > I think you need to give other archs a chance to support this with a > > design that considers the offset case as a first class citizen rather > > than an afterthought. > > I'll consider this. Given the fact I can use your existing > get_dev_pagemap infrastructure to look up the p2pmem device this > probably isn't as hard as I thought it would be anyway (we probably > don't even need a page flag). We'd just have lookup the dev_pagemap, > test if it's a p2pmem device, and if so, call a p2pmem_dma_map function > which could apply the offset or do any other arch specific logic (if > necessary). I'm still not 100% why do you need a "p2mem device" mind you ... Cheers, Ben.