On Fri, Aug 13, 2021 at 01:31:38AM -0500, Alex Sierra wrote:

From: Ralph Campbell <redacted>

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@lst.de>