[RFC PATCH 5/5] mm: changes to unref pages with Generic type

[Christoph Hellwig]

On Thu, May 27, 2021 at 07:08:09PM -0400, Felix Kuehling wrote:
> From: Alex Sierra <alex.sierra at amd.com>
> 
> pages in device mapping refcounts are 1-based, instead
> of 0-based. If refcount 1, means it can be freed.
> This logic is not set for Generic memory type. Therefore,
> its release is threated as a normal page, instead of
> the callback device driver release it.

So we really need to stop this magic one off refcount.  We had a WIP
patchset to do that, and we need to finish that off instad of piling on
more hacks.