Re: [PATCH v2] mm: folio_zero_user: open code range computation in folio_zero_user()

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

On 2/6/26 06:42, Ankur Arora wrote:
> 
> David Hildenbrand (Arm) <david@kernel.org> writes:
> 
>> On 2/5/26 06:48, Ankur Arora wrote:
>>> Andrew Morton <akpm@linux-foundation.org> writes:
>>>
>>> Yes agreed.
>>> The first u64 is because currently struct range only supports that.
>>> Then the cast to signed long is because the range can be negative
>>> and the clear_contig_highpages() is only done if nr_pages > 0.
>>
>> That makes sense to me.
>>
>>> And, the third one is almost certainly unnecessary for any realistic
>>> hugepage size but since nr_pages is being truncating, I wanted that
>>> to be explicit.
>>
>> But the non-silent truncation is no better? IOW, it doesn't matter.
> 
> I never seem to get them but I thought we had some kconfig option that
> makes gcc give a warning to that effect.

I think we do it all the time :)

> 
> I can update this patch to just implicitly truncate.
> 

Yeah, I think the implicit once can just be dropped.

>> You could just make clear_contig_highpages() consume an unsigned long ...
> 
> Unfortunately that'll be an even bigger mess. The clear_contig_highpages()
> version in mm-stable uses the unsigned intness of nr_pages all over:

Right.

In any case, thanks and feel free to add

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

-- 
Cheers,

David