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

[David Hildenbrand (Arm)]

On 2/5/26 06:48, Ankur Arora wrote:
> Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> writes:
>
> > On Wed, 4 Feb 2026 22:01:42 +0100 "David Hildenbrand (arm)" <david@xxxxxxxxxx> wrote:
> >
> > > I'm late, maybe this is already upstream.
> >
> > It's in mm-unstable.  The second round of MM upstreaming is two weeks hence.
> >
> > > TBH, without the clamp that looks much more readable here.
> >
> > me too.
> >
> > > Is that cast really required?
> >
> > Seems not.  The types for nr_pages are a bit chaotic - u64->long->uint.
>
> 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.

You could just make clear_contig_highpages() consume an unsigned long ...

--
Cheers,

David