[PATCH v4] rust: sync: replace `kernel::c_str!` with C-Strings

[PATCH v4] rust: sync: replace `kernel::c_str!` with C-Strings

[Tamir Duberstein]

From: Tamir Duberstein <tamird@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 <gregkh@linuxfoundation.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Benno Lossin <lossin@kernel.org>
Signed-off-by: Tamir Duberstein <tamird@gmail.com>
---
This intentionally includes only those changes that can be taken through
the Rust tree. I will send separate patches after rc1 for the remaining
changes.
---
Changes in v4:
- Drop applied patches.
- Drop rust/kernel/net/phy.rs patch; will send to netdev after rc1.
- Drop changes to `new_spinlock!`; allow callers to pass plain string
  literals rather than C-string literals.
- Link to v3: https://patch.msgid.link/20251113-core-cstr-cstrings-v3-0-411b34002774@gmail.com

Changes in v3:
- Include all patches that can be taken through the rust tree.
- Split "sync" patch into "sync" and "workqueue". Kept the tags on both.
- Link to v2: https://lore.kernel.org/r/20250925-core-cstr-cstrings-v2-0-78e0aaace1cd@gmail.com

Changes in v2:
- Rebase.
- Add two patches to address new code.
- Drop incorrectly applied Acked-by tags from Danilo.
- Link to v1: https://lore.kernel.org/r/20250710-core-cstr-cstrings-v1-0-027420ea799e@gmail.com
---
 rust/kernel/sync.rs | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/rust/kernel/sync.rs b/rust/kernel/sync.rs
index cf5b638a097d..c94753d6413e 100644
--- a/rust/kernel/sync.rs
+++ b/rust/kernel/sync.rs
@@ -48,7 +48,6 @@ impl LockClassKey {
     ///
     /// # Examples
     /// ```
-    /// # use kernel::c_str;
     /// # use kernel::alloc::KBox;
     /// # use kernel::types::ForeignOwnable;
     /// # use kernel::sync::{LockClassKey, SpinLock};
@@ -60,7 +59,7 @@ impl LockClassKey {
     /// {
     ///     stack_pin_init!(let num: SpinLock<u32> = SpinLock::new(
     ///         0,
-    ///         c_str!("my_spinlock"),
+    ///         c"my_spinlock",
     ///         // SAFETY: `key_ptr` is returned by the above `into_foreign()`, whose
     ///         // `from_foreign()` has not yet been called.
     ///         unsafe { <Pin<KBox<LockClassKey>> as ForeignOwnable>::borrow(key_ptr) }

---
base-commit: bf724be7f00cf2cbafc105422476f6242e917a90
change-id: 20250710-core-cstr-cstrings-1faaa632f0fd

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

Re: [PATCH v4] rust: sync: replace `kernel::c_str!` with C-Strings

[Miguel Ojeda]

On Mon, Nov 17, 2025 at 5:38 PM Tamir Duberstein <tamird@kernel.org> wrote:
>
> From: Tamir Duberstein <tamird@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 <gregkh@linuxfoundation.org>
> Reviewed-by: Alice Ryhl <aliceryhl@google.com>
> Reviewed-by: Benno Lossin <lossin@kernel.org>
> Signed-off-by: Tamir Duberstein <tamird@gmail.com>

Applied to `rust-next` -- thanks everyone!

Cheers,
Miguel