Re: [PATCH] rust: bindings: add `rust_helper_wait_for_completion` helper function

[Boqun Feng]

On Thu, Oct 02, 2025 at 10:06:17AM +0000, Guangbo Cui wrote:
> > -extern void wait_for_completion(struct completion *);
> > -extern void wait_for_completion_io(struct completion *);
> > -extern int wait_for_completion_interruptible(struct completion *x);
> > -extern int wait_for_completion_killable(struct completion *x);
> > -extern int wait_for_completion_state(struct completion *x, unsigned int state);
> > -extern unsigned long wait_for_completion_timeout(struct completion *x,
> > +extern void __wait_for_completion(struct completion *);
> > +extern void __wait_for_completion_io(struct completion *);
> > +extern int __wait_for_completion_interruptible(struct completion *x);
> > +extern int __wait_for_completion_killable(struct completion *x);
> > +extern int __wait_for_completion_state(struct completion *x, unsigned int state);
> > +extern unsigned long __wait_for_completion_timeout(struct completion *x,
> >  						   unsigned long timeout);
> > -extern unsigned long wait_for_completion_io_timeout(struct completion *x,
> > +extern unsigned long __wait_for_completion_io_timeout(struct completion *x,
> >  						    unsigned long timeout);
> > -extern long wait_for_completion_interruptible_timeout(
> > +extern long __wait_for_completion_interruptible_timeout(
> >  	struct completion *x, unsigned long timeout);
> > -extern long wait_for_completion_killable_timeout(
> > +extern long __wait_for_completion_killable_timeout(
> >  	struct completion *x, unsigned long timeout);
> >  extern bool try_wait_for_completion(struct completion *x);
> >  extern bool completion_done(struct completion *x);
> > @@ -139,4 +134,79 @@ extern void complete(struct completion *);
> >  extern void complete_on_current_cpu(struct completion *x);
> >  extern void complete_all(struct completion *);
> >  
> > +#define wait_for_completion(x)						\
> > +({									\
> > +	sdt_might_sleep_start_timeout(NULL, -1L);			\
> > +	__wait_for_completion(x);					\
> > +	sdt_might_sleep_end();						\
> > +})
> 
> The DEPT patch series changed `wait_for_completion` into a macro.
> Because bindgen cannot handle function-like macros, this caused
> Rust build errors. Add a helper function to fix it.
> 
> ```
> error[E0425]: cannot find function `wait_for_completion` in crate `bindings`
>      --> rust/kernel/sync/completion.rs:110:28
>       |
>   110 |         unsafe { bindings::wait_for_completion(self.as_raw()) };
>       |                            ^^^^^^^^^^^^^^^^^^^ help: a function with a similar name exists: `__wait_for_completion`
>       |
>      ::: /root/linux/rust/bindings/bindings_generated.rs:33440:5
>       |
> 33440 |     pub fn __wait_for_completion(arg1: *mut completion);
>       |     ---------------------------------------------------- similarly named function `__wait_for_completion` defined here
> 
> error: aborting due to 1 previous error
> 
> For more information about this error, try `rustc --explain E0425`.
> ```
> 

I think Danilo already made it clear, please fold this the existing
patch. Moreover, since this patchset doesn't adjust init_completion()
from the Rust side, the result is Rust code will also use the same dept
key for completion, which has to be fixed if dept wants to be in-tree.

Regards,
Boqun

> Signed-off-by: Guangbo Cui <2407018371@xxxxxx>
> ---
>  rust/helpers/completion.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/rust/helpers/completion.c b/rust/helpers/completion.c
> index b2443262a2ae..5bae5e749def 100644
> --- a/rust/helpers/completion.c
> +++ b/rust/helpers/completion.c
> @@ -6,3 +6,8 @@ void rust_helper_init_completion(struct completion *x)
>  {
>  	init_completion(x);
>  }
> +
> +void rust_helper_wait_for_completion(struct completion *x)
> +{
> +	wait_for_completion(x);
> +}
> -- 
> 2.43.0
>