[PATCH v1 1/2] ext4/xfs: add page refcount helper

[Jason Gunthorpe]

On Thu, Oct 14, 2021 at 10:39:27AM -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.
> 
> Signed-off-by: Ralph Campbell <rcampbell at nvidia.com>
> Signed-off-by: Alex Sierra <alex.sierra at amd.com>
> Reviewed-by: Christoph Hellwig <hch at lst.de>
> Acked-by: Theodore Ts'o <tytso at mit.edu>
> Acked-by: Darrick J. Wong <djwong at kernel.org>
> ---
> 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.
> ---
>  fs/dax.c            |  4 ++--
>  fs/ext4/inode.c     |  5 +----
>  fs/fuse/dax.c       |  4 +---
>  fs/xfs/xfs_file.c   |  4 +---
>  include/linux/dax.h | 10 ++++++++++
>  5 files changed, 15 insertions(+), 12 deletions(-)

Reviewed-by: Jason Gunthorpe <jgg at nvidia.com>

Jason