Re: [PATCH 5/7] rust: file: add `Kuid` wrapper

[Christian Brauner]

On Wed, Nov 29, 2023 at 05:48:15PM +0100, Peter Zijlstra wrote:
> On Wed, Nov 29, 2023 at 05:28:27PM +0100, Christian Brauner wrote:
> 
> > > +pid_t rust_helper_task_tgid_nr_ns(struct task_struct *tsk,
> > > +				  struct pid_namespace *ns)
> > > +{
> > > +	return task_tgid_nr_ns(tsk, ns);
> > > +}
> > > +EXPORT_SYMBOL_GPL(rust_helper_task_tgid_nr_ns);
> > 
> > I'm a bit puzzled by all these rust_helper_*() calls. Can you explain
> > why they are needed? Because they are/can be static inlines and that
> > somehow doesn't work?
> 
> Correct, because Rust can only talk to C ABI, it cannot use C headers.
> Bindgen would need to translate the full C headers into valid Rust for
> that to work.
> 
> I really think the Rust peoples should spend more effort on that,
> because you are quite right, all this wrappery is tedious at best.

The problem is that we end up with a long list of explicit exports that
also are all really weirdly named like rust_helper_*(). I wouldn't even
complain if it they were somehow auto-generated but as you say that
might be out of scope.

The thing is though that if I want to change the static inlines I know
also have to very likely care about these explicit Rust wrappers which
seems less than ideal.

So if we could not do rust_helper_*() exports we'd probably be better
off.