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

[David Hildenbrand (Arm)]

On 2/6/26 06:42, Ankur Arora wrote:
> David Hildenbrand (Arm) <david@xxxxxxxxxx> writes:
>
> > On 2/5/26 06:48, Ankur Arora wrote:
> > > Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> 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@xxxxxxxxxx>

--
Cheers,

David