Re: [PATCH v2 12/18] devdax: Move address_space helpers to the DAX core

Dan Williams
2022-09-29T22:44:31Z

Alistair Popple wrote:
>
> Dan Williams <dan.j.williams@intel.com> 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!