Re: [PATCH V3] implement `ww_mutex` abstraction for the Rust tree

[Alice Ryhl]

On Thu, Jun 19, 2025 at 4:33 PM Onur <work@xxxxxxxxxxxxx> wrote:
>
> On Thu, 19 Jun 2025 16:14:01 +0200
> Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
>
> > On Thu, Jun 19, 2025 at 05:06:56PM +0300, Onur Özkan wrote:
> > > +bool rust_helper_ww_mutex_is_locked(struct ww_mutex *lock)
> > > +{
> > > +   return ww_mutex_is_locked(lock);
> > > +}
> >
> > Do we really need this? In general I dislike all the _is_locked()
> > functions and would ideally like to remove them.
> >
> > Pretty much the only useful pattern for any of the _is_locked()
> > functions is:
> >
> >   WARN_ON_ONCE(!foo_is_locked(&foo));
> >
> > Any other use is dodgy as heck.
> >
> >
>
> It's an abstraction of `ww_mutex_is_locked`. Since this is an
> abstraction module, as long as `ww_mutex_is_locked` exists I think
> we should keep it. FWIW it's also quite useful for tests.

We're not just adding copies of all of the C methods - instead we
focus on the things we have a use-case for. If you're using them in
tests, then that could make sense, but otherwise you shouldn't add
them.

Alice