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Well here I am saying the buffer has a P2P struct page so that is all you actually need to know. It just follows the existing proven path in the IO stack. > So to generalize this for upstreaming it would need something like a > giant whitelist of exporter/importer combinations which are known to > work together and not crash the kernel in surprising and hard to > track down ways. Well I think the mapping type proposal goes a long way toward dealing wiht this problem. Let's shelve the discussion until after we discuss that with patches. > > Reworking the block stack to not rely on page is also a good path, but > > probably alot harder. :\ > > Yeah, that would be really really nice to have and the latest > patches for extending the struct file stuff actually looked quite > promising. Yeah, I thought the dma token through the IO stack looked very interesting too. I hope it eventually succeeds! Jason