Re: [PATCH RFC 02/11] rust: sync: atomic: Add Atomic<u{8,16}>
flat view
From: "Gary Guo" <gary@garyguo.net>
Date: 2026-10-11 13:04:59
Also in:
driver-core, linux-kselftest, lkml, rust-for-linux
On Sun Oct 11, 2026 at 1:52 PM BST, Thomas Weißschuh wrote:
Add generic atomic support for small unsigned integers that have an `AtomicImpl` with the same size and alignment. Also extend the unit tests. Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
AtomicType is something that I'm getting rid of next cycle. The plan is to convert atomic to use `kernel::mem::AsRepr`. Best, Gary
quoted hunk ↗ jump to hunk
--- rust/kernel/sync/atomic/predefine.rs | 44 ++++++++++++++++++++++++++++-------- 1 file changed, 35 insertions(+), 9 deletions(-)diff --git a/rust/kernel/sync/atomic/predefine.rs b/rust/kernel/sync/atomic/predefine.rs index 3d63f40791fa..4c1fb5e08dc2 100644 --- a/rust/kernel/sync/atomic/predefine.rs +++ b/rust/kernel/sync/atomic/predefine.rs@@ -113,6 +113,32 @@ fn rhs_into_delta(rhs: isize) -> isize_atomic_repr { } } +// SAFETY: `u8` and `i8` has the same size and alignment, and `u8` is round-trip transmutable to +// `i8`. +unsafe impl super::AtomicType for u8 { + type Repr = i8; +} + +// SAFETY: The wrapping add result of two `i8`s is a valid `u8`. +unsafe impl super::AtomicAdd<u8> for u8 { + fn rhs_into_delta(rhs: u8) -> i8 { + rhs as i8 + } +} + +// SAFETY: `u16` and `i16` has the same size and alignment, and `u16` is round-trip transmutable to +// `i16`. +unsafe impl super::AtomicType for u16 { + type Repr = i16; +} + +// SAFETY: The wrapping add result of two `i16`s is a valid `u16`. +unsafe impl super::AtomicAdd<u16> for u16 { + fn rhs_into_delta(rhs: u16) -> i16 { + rhs as i16 + } +} +