[PATCH 1/4] rust: fix signature of rust_fmt_argument
Alice Ryhl
aliceryhl at google.com
Fri Feb 28 08:44:21 UTC 2025
On Fri, Feb 28, 2025 at 9:20 AM Andreas Hindborg <a.hindborg at kernel.org> wrote:
>
> "Alice Ryhl" <aliceryhl at google.com> writes:
>
> > Without this change, the rest of this series will emit the following
> > error message:
> >
> > error[E0308]: `if` and `else` have incompatible types
> > --> <linux>/rust/kernel/print.rs:22:22
> > |
> > 21 | #[export]
> > | --------- expected because of this
> > 22 | unsafe extern "C" fn rust_fmt_argument(
> > | ^^^^^^^^^^^^^^^^^ expected `u8`, found `i8`
> > |
> > = note: expected fn item `unsafe extern "C" fn(*mut u8, *mut u8, *mut c_void) -> *mut u8 {bindings::rust_fmt_argument}`
> > found fn item `unsafe extern "C" fn(*mut i8, *mut i8, *const c_void) -> *mut i8 {print::rust_fmt_argument}`
> >
> > The error may be different depending on the architecture.
> >
> > Fixes: 787983da7718 ("vsprintf: add new `%pA` format specifier")
> > Signed-off-by: Alice Ryhl <aliceryhl at google.com>
> > ---
> > lib/vsprintf.c | 2 +-
> > rust/kernel/print.rs | 8 ++++----
> > 2 files changed, 5 insertions(+), 5 deletions(-)
> >
> > diff --git a/lib/vsprintf.c b/lib/vsprintf.c
> > index 56fe96319292..a8ac4c4fffcf 100644
> > --- a/lib/vsprintf.c
> > +++ b/lib/vsprintf.c
> > @@ -2285,7 +2285,7 @@ int __init no_hash_pointers_enable(char *str)
> > early_param("no_hash_pointers", no_hash_pointers_enable);
> >
> > /* Used for Rust formatting ('%pA'). */
> > -char *rust_fmt_argument(char *buf, char *end, void *ptr);
> > +char *rust_fmt_argument(char *buf, char *end, const void *ptr);
> >
> > /*
> > * Show a '%p' thing. A kernel extension is that the '%p' is followed
> > diff --git a/rust/kernel/print.rs b/rust/kernel/print.rs
> > index b19ee490be58..8551631dedf1 100644
> > --- a/rust/kernel/print.rs
> > +++ b/rust/kernel/print.rs
> > @@ -6,13 +6,13 @@
> > //!
> > //! Reference: <https://docs.kernel.org/core-api/printk-basics.html>
> >
> > -use core::{
> > +use core::fmt;
> > +
> > +use crate::{
> > ffi::{c_char, c_void},
> > - fmt,
> > + str::RawFormatter,
> > };
> >
> > -use crate::str::RawFormatter;
> > -
> > // Called from `vsprintf` with format specifier `%pA`.
> > #[expect(clippy::missing_safety_doc)]
> > #[no_mangle]
>
> The changes in this last hunk is not mentioned in the commit message.
The diff is rendered pretty poorly, but this is just importing
integers from crate::ffi instead of core::ffi, and I do believe that
the commit message makes it clear that this is needed.
Alice
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