[PATCH] rust: kunit: replace `kernel::c_str!` with C-Strings

[Tamir Duberstein]

From: Tamir Duberstein <tam...@gmail.com>

C-String literals were added in Rust 1.77. Replace instances of
`kernel::c_str!` with C-String literals where possible.

Acked-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
Reviewed-by: Alice Ryhl <alic...@google.com>
Reviewed-by: Benno Lossin <los...@kernel.org>
Signed-off-by: Tamir Duberstein <tam...@gmail.com>
---
rust/kernel/kunit.rs | 11 ++++-------
rust/macros/kunit.rs | 10 +++++-----
scripts/rustdoc_test_gen.rs | 4 ++--
3 files changed, 11 insertions(+), 14 deletions(-)

diff --git a/rust/kernel/kunit.rs b/rust/kernel/kunit.rs
index 79436509dd73..21aef6c97325 100644
--- a/rust/kernel/kunit.rs
+++ b/rust/kernel/kunit.rs
@@ -9,9 +9,6 @@
use crate::fmt;
use crate::prelude::*;

-#[cfg(CONFIG_PRINTK)]
-use crate::c_str;
-
/// Prints a KUnit error-level message.
///
/// Public but hidden since it should only be used from KUnit generated code.
@@ -22,7 +19,7 @@ pub fn err(args: fmt::Arguments<'_>) {
#[cfg(CONFIG_PRINTK)]
unsafe {
bindings::_printk(
- c_str!("\x013%pA").as_char_ptr(),
+ c"\x013%pA".as_char_ptr(),
core::ptr::from_ref(&args).cast::<c_void>(),
);
}
@@ -38,7 +35,7 @@ pub fn info(args: fmt::Arguments<'_>) {
#[cfg(CONFIG_PRINTK)]
unsafe {
bindings::_printk(
- c_str!("\x016%pA").as_char_ptr(),
+ c"\x016%pA".as_char_ptr(),
core::ptr::from_ref(&args).cast::<c_void>(),
);
}
@@ -60,7 +57,7 @@ macro_rules! kunit_assert {
break 'out;
}

- static FILE: &'static $crate::str::CStr = $crate::c_str!($file);
+ static FILE: &'static $crate::str::CStr = $file;
static LINE: i32 = ::core::line!() as i32 - $diff;
static CONDITION: &'static $crate::str::CStr = $crate::c_str!(stringify!($condition));

@@ -253,7 +250,7 @@ pub const fn kunit_case_null() -> kernel::bindings::kunit_case {
/// }
///
/// static mut KUNIT_TEST_CASES: [kernel::bindings::kunit_case; 2] = [
-/// kernel::kunit::kunit_case(kernel::c_str!("name"), test_fn),
+/// kernel::kunit::kunit_case(c"name", test_fn),
/// kernel::kunit::kunit_case_null(),
/// ];
/// kernel::kunit_unsafe_test_suite!(suite_name, KUNIT_TEST_CASES);
diff --git a/rust/macros/kunit.rs b/rust/macros/kunit.rs
index b395bb053695..3d7724b35c0f 100644
--- a/rust/macros/kunit.rs
+++ b/rust/macros/kunit.rs
@@ -102,8 +102,8 @@ pub(crate) fn kunit_tests(attr: TokenStream, ts: TokenStream) -> TokenStream {
// unsafe extern "C" fn kunit_rust_wrapper_bar(_test: *mut ::kernel::bindings::kunit) { bar(); }
//
// static mut TEST_CASES: [::kernel::bindings::kunit_case; 3] = [
- // ::kernel::kunit::kunit_case(::kernel::c_str!("foo"), kunit_rust_wrapper_foo),
- // ::kernel::kunit::kunit_case(::kernel::c_str!("bar"), kunit_rust_wrapper_bar),
+ // ::kernel::kunit::kunit_case(c"foo", kunit_rust_wrapper_foo),
+ // ::kernel::kunit::kunit_case(c"bar", kunit_rust_wrapper_bar),
// ::kernel::kunit::kunit_case_null(),
// ];
//
@@ -133,7 +133,7 @@ pub(crate) fn kunit_tests(attr: TokenStream, ts: TokenStream) -> TokenStream {
writeln!(kunit_macros, "{kunit_wrapper}").unwrap();
writeln!(
test_cases,
- " ::kernel::kunit::kunit_case(::kernel::c_str!(\"{test}\"), {kunit_wrapper_fn_name}),"
+ " ::kernel::kunit::kunit_case(c\"{test}\", {kunit_wrapper_fn_name}),"
)
.unwrap();
writeln!(
@@ -143,7 +143,7 @@ pub(crate) fn kunit_tests(attr: TokenStream, ts: TokenStream) -> TokenStream {
#[allow(unused)]
macro_rules! assert {{
($cond:expr $(,)?) => {{{{
- kernel::kunit_assert!("{test}", "{path}", 0, $cond);
+ kernel::kunit_assert!("{test}", c"{path}", 0, $cond);
}}}}
}}

@@ -151,7 +151,7 @@ macro_rules! assert {{
#[allow(unused)]
macro_rules! assert_eq {{
($left:expr, $right:expr $(,)?) => {{{{
- kernel::kunit_assert_eq!("{test}", "{path}", 0, $left, $right);
+ kernel::kunit_assert_eq!("{test}", c"{path}", 0, $left, $right);
}}}}
}}
"#
diff --git a/scripts/rustdoc_test_gen.rs b/scripts/rustdoc_test_gen.rs
index be0561049660..967064ebd391 100644
--- a/scripts/rustdoc_test_gen.rs
+++ b/scripts/rustdoc_test_gen.rs
@@ -174,7 +174,7 @@ pub extern "C" fn {kunit_name}(__kunit_test: *mut ::kernel::bindings::kunit) {{
macro_rules! assert {{
($cond:expr $(,)?) => {{{{
::kernel::kunit_assert!(
- "{kunit_name}", "{real_path}", __DOCTEST_ANCHOR - {line}, $cond
+ "{kunit_name}", c"{real_path}", __DOCTEST_ANCHOR - {line}, $cond
);
}}}}
}}
@@ -184,7 +184,7 @@ macro_rules! assert {{
macro_rules! assert_eq {{
($left:expr, $right:expr $(,)?) => {{{{
::kernel::kunit_assert_eq!(
- "{kunit_name}", "{real_path}", __DOCTEST_ANCHOR - {line}, $left, $right
+ "{kunit_name}", c"{real_path}", __DOCTEST_ANCHOR - {line}, $left, $right
);
}}}}
}}

---
base-commit: 8f0b4cce4481fb22653697cced8d0d04027cb1e8
change-id: 20251222-cstr-kunit-be68dd8cfbd5

Best regards,
--
Tamir Duberstein <tam...@gmail.com>

[Miguel Ojeda]

On Mon, Dec 22, 2025 at 1:28 PM Tamir Duberstein <tam...@kernel.org> wrote:
>
> From: Tamir Duberstein <tam...@gmail.com>
>
> C-String literals were added in Rust 1.77. Replace instances of
> `kernel::c_str!` with C-String literals where possible.
>
> Acked-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
> Reviewed-by: Alice Ryhl <alic...@google.com>
> Reviewed-by: Benno Lossin <los...@kernel.org>
> Signed-off-by: Tamir Duberstein <tam...@gmail.com>

Thanks for these (and all the others you just sent) cleanups.

David et al.: I can pick this up if you want with an Acked-by -- thanks!

Cheers,
Miguel