Re: [PATCH 3/5] mm: export zap_page_range_single and list_lru_add/del

[Lorenzo Stoakes <lorenzo.stoakes@oracle.com>]

On Thu, Feb 05, 2026 at 01:24:09PM +0100, Miguel Ojeda wrote:
> On Thu, Feb 5, 2026 at 12:58 PM Lorenzo Stoakes
> <lorenzo.stoakes@oracle.com> wrote:
> >
> > What??
> >
> > Alice - can you confirm rust isn't exporting stuff that isn't explicitly marked
> > EXPORT_SYMBOL*() for use by other rust modules?
> >
> > It's important we keep this in sync, otherwise rust is overriding kernel policy.
>
> Currently, Rust GPL-exports every mangled symbol from the `kernel`
> crate. To call something you would need to be a Rust caller (not C --
> that is not supported at all, even if technically you could hack
> something up) and the Rust API would then need to give you access to
> it (i.e. you need to be able to pass the Rust language rules, e.g.
> being public etc.).
>
> In this case if we are talking about the `VmaRef` type, someone that
> can get a reference to a value of that type could then call the
> `zap_page_range_single` method. That in turns would try to call the C
> one, but that one is not exported, right? So it should be fine.
>

OK cool. Thanks for the explanation.

> In the future, for Rust, we may specify whether a particular crate
> exports or not (and perhaps even allow to export non-GPL, but
> originally it was decided to only export GPL stuff to be on the safe
> side; and perhaps in certain namespaces etc.).

We'd definitely need to keep this in sync with C exports, maybe we can find
a nice way of doing/checking this.

Generally we're _very_ conservative about exports, and actually it'd be
nice if maybe rust only provided GPL ones. The GPL is a good thing :) But I
guess we can figure that out later.

>
> Cheers,
> Miguel

Cheers, Lorenzo