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Add a helper macro tha= t >>> allows this. >>> >>> Signed-off-by: Alexandre Courbot >>> --- >>> rust/kernel/bug.rs | 10 ++++++++++ >>> 1 file changed, 10 insertions(+) >>> >>> diff --git a/rust/kernel/bug.rs b/rust/kernel/bug.rs >>> index ed943960f851..2fefc0aeef81 100644 >>> --- a/rust/kernel/bug.rs >>> +++ b/rust/kernel/bug.rs >>> @@ -130,3 +130,13 @@ macro_rules! warn_on { >>> cond >>> }}; >>> } >>> + >>> +/// Report a warning if `res` is an error and return it unmodified. >>> +#[macro_export] >>> +macro_rules! warn_on_err { >>> + ($res:expr) =3D> {{ >>> + let res =3D $res; >>> + let _ =3D $crate::warn_on!(res.is_err()); >>> + res >>> + }}; >>> +} >> >> >> I think `warn_on_err` could just be expressed as >> >> res.inspect_err(|_| warn_on!(true)) > > This would turn the verbose error message into something like > > [true] module.rs > > I.e. the expression passed as argument won't be printed. > > That being said, my version has the exact same problem and I don't see > how we can fix this without splitting `warn_on` and making it more > complex. > > Since this was done as a small convenience, I think I will just remove > this from this patchset and revisit later as a separate series. Something like this? #[macro_export] macro_rules! warn { () =3D> {{ const WARN_ON_FLAGS: u32 =3D $crate::bug::bugflag_taint($crate::bin= dings::TAINT_WARN); $crate::warn_flags!(file!(), WARN_ON_FLAGS); }} ($msg:expr) =3D> {{ #[cfg(CONFIG_DEBUG_BUGVERBOSE_DETAILED)] const _COND_STR: &str =3D concat!("[", $msg, "] ", file!()); #[cfg(not(CONFIG_DEBUG_BUGVERBOSE_DETAILED))] const _COND_STR: &str =3D file!(); const WARN_ON_FLAGS: u32 =3D $crate::bug::bugflag_taint($crate::bin= dings::TAINT_WARN); $crate::warn_flags!(_COND_STR, WARN_ON_FLAGS); }}; } #[macro_export] macro_rules! warn_on { ($cond:expr) =3D> {{ let cond =3D $cond; if cond { warn!(stringify!($cond)); } cond }}; } Then you can just use a `warn!()` with custom message. Best, Gary