Re: [PATCH] rust: add trylock method support for lock backend

[Gary Guo <gary@garyguo.net>]

On Sat, 14 Sep 2024 22:35:29 -0700
Boqun Feng <boqun.feng@gmail.com> wrote:

> > diff --git a/rust/helpers/spinlock.c b/rust/helpers/spinlock.c
> > index acc1376b833c..775ed4d549ae 100644
> > --- a/rust/helpers/spinlock.c
> > +++ b/rust/helpers/spinlock.c
> > @@ -22,3 +22,8 @@ void rust_helper_spin_unlock(spinlock_t *lock)
> >  {
> >  	spin_unlock(lock);
> >  }
> > +
> > +int rust_helper_spin_trylock(spinlock_t *lock)  
> 
> I'd just change this to `boolean`, but I don't whether it affects
> LTO-inlining, Gary?
> 

I don't see why it would affect LTO inlining. The additional cast
should be easily optimized away.

However I'd be wary of the signature going out-of-sync compared to rest
of C. If we later use bindgen's automatic helper generation or if the C
side made spin_trylock an externed function, then we would have issue
(compilation issue, but still...)

I think we should stick with `int` unless we change the signature of the
static inline functionn to also return `bool`.

Best,
Gary


> > +{
> > +	return spin_trylock(lock);
> > +}