Alistair Popple wrote: > The procfs mmu files such as smaps and pagemap currently ignore devdax and > fsdax pages because these pages are considered special. A future change > will start treating these as normal pages, meaning they can be exposed via > smaps and pagemap. > > The only difference is that devdax and fsdax pages can never be pinned for > DMA via FOLL_LONGTERM, so add an explicit check in pte_is_pinned() to > reflect that. I don't understand this patch. pin_user_pages() is also used for Direct-I/O page pinning, so the comment about FOLL_LONGTERM is wrong, and I otherwise do not understand what goes wrong if the only pte_is_pinned() user correctly detects the pin state?
