Re: [Patch v3 2/2] mm/huge_memory: merge uniform_split_supported() and non_uniform_split_supported()

[Zi Yan <ziy@nvidia.com>]

On 21 Nov 2025, at 11:50, Andrew Morton wrote:

> On Fri, 21 Nov 2025 09:59:42 -0500 Zi Yan <ziy@nvidia.com> wrote:
>
>>>
>>> 2. A further cleanup attempt:
>>>
>>>  https://lkml.kernel.org/r/136E8B1C-3352-412C-8038-627F5CC8A112@nvidia.com
>>>
>>> This one is the related mail.
>>>
>>> I proposed one version in
>>>
>>>  http://lkml.kernel.org/r/20251114075703.10434-1-richard.weiyang@gmail.com
>>>
>>> But it is not proper, will do follow up work later.
>>
>> Please refrain from sending more patches related to __folio_split() and its
>> related functions until the above hotfix is merged.
>
> You're referring to
> https://lkml.kernel.org/r/20251119235302.24773-1-richard.weiyang@gmail.com?

Yes.

>
>> I also have an ongoing
>> cleanup patchset[1] and want to get it in before any other changes.
>
> I remain unclear on the status of this patchset.  Is it considered good
> to upstream or is additional work required?

I am still having a discussion with David Hildenbrand about it and hopefully
get it sorted out soon. The reason is that the above hotfix is good for
backport but future user of folio_split_supported() can still dereference
a NULL folio->mapping unless they check folio->mapping != NULL beforehand.
I would like to avoid that by refactoring folio_split_support().

Wei’s further cleanup patch can come after my refactoring by just moving
a code hunk above.

Best Regards,
Yan, Zi