Alistair Popple wrote: > The page->mapping and page->index fields are normally used by the > pagecache and rmap for looking up virtual mappings of pages. FS DAX > implements it's own kind of page cache and rmap look ups so these > fields are unnecessary. They are currently only used to detect > error/warning conditions which should never occur. > > A future change will change the way shared mappings are detected by > doing normal page reference counting instead, so remove the > unnecessary checks. Ignore my comment on patch3, I fumble fingered the reply, it was meant to for this patch. I.e. that "future change" should just be present before removing old logic.