[PATCH 2/2] rust: sync: atomic: clarify AtomicAdd safety comment

Sagar Taunk
2026-04-27T20:33:29Z

The previous safety comment for AtomicAdd was marked with a TODO
and contained a grammatically broken sentence that was difficult to
parse. Rewrite the safety requirement to clearly state the actual
contract: calling wrapping_add with a delta from rhs_into_delta()
on a repr obtained via into_repr() from a valid Self must produce
a bit pattern valid for Self.

Signed-off-by: Sagar Taunk <sagartaunk2@gmail.com>
---
rust/kernel/sync/atomic.rs | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/rust/kernel/sync/atomic.rs b/rust/kernel/sync/atomic.rs
index 9cd009d57e35..b38d9a17f9e8 100644
--- a/rust/kernel/sync/atomic.rs
+++ b/rust/kernel/sync/atomic.rs
@@ -127,10 +127,9 @@ pub unsafe trait AtomicType: Sized + Copy {
///
/// # Safety
///
-// TODO: Properly defines `wrapping_add` in the following comment.
-/// `wrapping_add` any value of type `Self::Repr::Delta` obtained by [`Self::rhs_into_delta()`] to
-/// any value of type `Self::Repr` obtained through transmuting a value of type `Self` to must
-/// yield a value with a bit pattern also valid for `Self`.
+/// Calling `wrapping_add` with any value of type `Self::Repr::Delta` produced by
+/// `Self::rhs_into_delta()`, on any `Self::Repr` value obtained via `into_repr()` from a valid
+/// `Self`, must produce a bit pattern also valid for `Self`.
pub unsafe trait AtomicAdd<Rhs = Self>: AtomicType {
/// Converts `Rhs` into the `Delta` type of the atomic implementation.
fn rhs_into_delta(rhs: Rhs) -> <Self::Repr as AtomicImpl>::Delta;
--
2.54.0