[PATCH v6 01/13] ext4/xfs: add page refcount helper

[Christoph Hellwig]

On Fri, Aug 13, 2021 at 01:31:38AM -0500, Alex Sierra wrote:
> From: Ralph Campbell <rcampbell at nvidia.com>
> 
> There are several places where ZONE_DEVICE struct pages assume a reference
> count == 1 means the page is idle and free. Instead of open coding this,
> add a helper function to hide this detail.
> 
> v3:
> [AS]: rename dax_layout_is_idle_page func to dax_page_unused
> 
> v4:
> [AS]: This ref count functionality was missing on fuse/dax.c.

These per-patch changelog goes under the "---", otherwise they totally
mess up the logs when commited to git.  Same for the other patches in
this series.

But the changes itself looks good:

Reviewed-by: Christoph Hellwig <hch at lst.de>