[PATCH v1 2/2] mm: remove extra ZONE_DEVICE struct page refcount

[Matthew Wilcox]

On Thu, Oct 14, 2021 at 10:39:28AM -0500, Alex Sierra wrote:
> From: Ralph Campbell <rcampbell at nvidia.com>
> 
> ZONE_DEVICE struct pages have an extra reference count that complicates the
> code for put_page() and several places in the kernel that need to check the
> reference count to see that a page is not being used (gup, compaction,
> migration, etc.). Clean up the code so the reference count doesn't need to
> be treated specially for ZONE_DEVICE.
> 
> 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>

Reviewed-by: Matthew Wilcox (Oracle) <willy at infradead.org>