Re: [PATCH] rust: error: use pr_warn_once! in from_errno

[FUJITA Tomonori <tomo@flapping.org>]

On Sat, 11 Jul 2026 23:09:19 +0200
alessioMaroni0 <alessiomaroni0@gmail.com> wrote:

> Replace crate::pr_warn! with crate::pr_warn_once! in Error::from_errno
> to prevent logging noise if an invalid errno is repeatedly passed.
> This resolves a pending TODO in the file.
> 
> Signed-off-by: alessioMaroni0 <alessiomaroni0@gmail.com>
> ---
>  rust/kernel/error.rs | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/rust/kernel/error.rs b/rust/kernel/error.rs
> index a56ba6309..2d3e31aff 100644
> --- a/rust/kernel/error.rs
> +++ b/rust/kernel/error.rs
> @@ -123,8 +123,7 @@ pub fn from_errno(errno: crate::ffi::c_int) -> Error {
>          if let Some(error) = Self::try_from_errno(errno) {
>              error
>          } else {
> -            // TODO: Make it a `WARN_ONCE` once available.
> -            crate::pr_warn!(
> +            crate::pr_warn_once!(
>                  "attempted to create `Error` with out of range `errno`: {}\n",
>                  errno

WARN_ONCE and pr_warn_once are not the same thing.

WARN_ONCE prints a full stack trace and register dump.

pr_warn_once is just sorta of printk.

I'll add warn_once macro after the patch to add bug macro [1] is
merged.

[1] https://lore.kernel.org/rust-for-linux/20260709000103.2912159-1-tomo@aliasing.net/