Re: [PATCH v2] rust: add mark_used macro

[Alice Ryhl <aliceryhl@google.com>]

On Wed, Sep 30, 2026 at 06:50:28PM +0900, FUJITA Tomonori wrote:
> > diff --git a/rust/kernel/tracepoint.rs b/rust/kernel/tracepoint.rs
> > index c6e80aa99e8e..29d2d2d0aca8 100644
> > --- a/rust/kernel/tracepoint.rs
> > +++ b/rust/kernel/tracepoint.rs
> > @@ -38,9 +38,7 @@ macro_rules! declare_trace {
> >  
> >              #[cfg(not(CONFIG_TRACEPOINTS))]
> >              {
> > -                // If tracepoints are disabled, insert a trivial use of each argument
> > -                // to avoid unused argument warnings.
> > -                $( let _unused = $argname; )*
> > +                $crate::mark_used!($($argname),*);
> >              }
> >          }
> >      )*}
> > 
> 
> Gentle ping. Could you take a look at the tracepoint.rs part? If it
> looks fine, I think it is easiest to take the patch through the Rust
> tree.

Why are we adding this macro?

I think it's better to prefer avoiding macros if we can. The current
code is familiar to people who know Rust idioms, and now you are
replacing it with a kernel-specific macro that such people will not be
familiar with.

Alice