On Sat, Dec 23, 2017 at 04:56:06PM -0800, Dan Williams wrote: > In support of removing the VM_MIXEDMAP indication from DAX VMAs, > introduce pfn_t_special() for drivers to indicate that _PAGE_SPECIAL > should be used for DAX ptes. This also helps identify drivers like > dccssblk that only want to use DAX in a read-only fashion without > get_user_pages() support. > > Ideally we could delete axonram and dcssblk DAX support, but if we need > to keep it better make it explicit that axonram and dcssblk only support > a sub-set of DAX due to missing _PAGE_DEVMAP support. I'd suggest to just delete it for now. If the powerpc and S/390 people have an interest in it they should resurrect it properly and fully.
