Alistair Popple wrote: > > Dan Williams <dan.j.williams@xxxxxxxxx> writes: > > [...] > > > +/** > > + * dax_zap_mappings_range - find first pinned page in @mapping > > + * @mapping: address space to scan for a page with ref count > 1 > > + * @start: Starting offset. Page containing 'start' is included. > > + * @end: End offset. Page containing 'end' is included. If 'end' is LLONG_MAX, > > + * pages from 'start' till the end of file are included. > > + * > > + * DAX requires ZONE_DEVICE mapped pages. These pages are never > > + * 'onlined' to the page allocator so they are considered idle when > > + * page->count == 1. A filesystem uses this interface to determine if > > Minor nit-pick I noticed while reading this but shouldn't that be > "page->count == 0" now? I put this patch set down for a couple days to attend a conference and now I am warming up my cache again. I believe the patch to make this zero based comes later in this series, but I definitely did not come back and fix this up in that patch, so good catch!