Re: [PATCH] kho: fix order calculation for kho_unpreserve_pages()

[Samiullah Khawaja <skhawaja@google.com>]

On Tue, May 19, 2026 at 03:33:30PM +0200, Pratyush Yadav wrote:
>From: "Pratyush Yadav (Google)" <pratyush@kernel.org>
>
>Commit 91e74fa8b1bc ("kho: make sure preservations do not span multiple
>NUMA nodes") made sure preservations from kho_preserve_pages() do not
>span multiple NUMA nodes. If they do, the order is reduced and tried
>again.
>
>The same logic was not implemented for kho_unpreserve_pages(). This can
>result in unpreserve calculating a different order than preserve, and
>thus not actually unpreserving the pages.
>
>Fix this by moving the order calculation logic to
>__kho_preserve_pages_order() and use it from both preserve and
>unpreserve paths.
>
>Move __kho_unpreserve() down to avoid having a forward declaration. Its
>users are further down in the file anyway. Also, it results in grouping
>for all the page-level preservation and unpreservation functions. This
>unfortunately makes the diff hard to read, but the main change in
>__kho_unpreserve() is to call __kho_preserve_pages_order() instead of
>open-coding the order calculation.
>
>Fixes: 91e74fa8b1bc ("kho: make sure preservations do not span multiple NUMA nodes")
>Cc: stable@vger.kernel.org
>Signed-off-by: Pratyush Yadav (Google) <pratyush@kernel.org>

Nice find, sashiko was also complaining about same on my kunit series:
https://sashiko.dev/#/patchset/20260512195135.804833-1-skhawaja%40google.com

Reviewed-by: Samiullah Khawaja <skhawaja@google.com>