Re: [PATCH v2 2/3] fs: stable_page_flags(): use folio_test_*() helpers

["David Hildenbrand (Arm)" <david@kernel.org>]

On 7/20/26 04:30, Jinjiang Tu wrote:
> Since commit 304daa8132a9 ("maps4: add /proc/kpageflags interface"),
> /proc/kpageflags directly operates on page->flags to determine page status.
> Later, commit 177975495914 ("proc: export more page flags in
> /proc/kpageflags") started using page helper functions when exposing new
> flags, leading to a mix of both approaches.
> 
> For tail pages, the original code did not return corresponding status.
> commit 0a71649cb724 ("/proc/kpageflags: return KPF_SLAB for slab tail
> pages") and commit 832fc1de01ae ("/proc/kpageflags: return KPF_BUDDY for
> "tail" buddy pages") made tail slab/buddy pages also return corresponding
> status. Then commit dee3d0bef2b0 ("proc: rewrite stable_page_flags()")
> made all tail pages return the same status as their head page, except for
> hwpoison and mapped flags. It also cached the folio's flags and operate on
> the flags directly to avoid concurrency issues if using folio_test_*()
> helpers.
> 
> Since commit 476d87d6a061 ("fs: stable_page_flags(): use snapshot_page()"),
> we can now safely switch to folio_test_*() helpers instead of directly
> operating on flags, which is more readable and consistent with the rest of
> the kernel. Only convert cfolio-specific flags (i.e., anon, ksm, swapcache)
> to folio_test_*() helpers, which reduces redundant code. Keep others
> unchanged due to they aren't folio-specific flags or coverting them doesn't
> cleanup.
> 
> No functional change is intended.
> 
> Signed-off-by: Jinjiang Tu <tujinjiang@huawei.com>

Acked-by: David Hildenbrand (Arm) <david@kernel.org>

-- 
Cheers,

David