From: Boqun Feng <boqun.feng@gmail.com>
To: linux-kernel@vger.kernel.org, rust-for-linux@vger.kernel.org,
lkmm@lists.linux.dev, linux-arch@vger.kernel.org
Cc: "Miguel Ojeda" <ojeda@kernel.org>,
"Alex Gaynor" <alex.gaynor@gmail.com>,
"Boqun Feng" <boqun.feng@gmail.com>,
"Gary Guo" <gary@garyguo.net>,
"Björn Roy Baron" <bjorn3_gh@protonmail.com>,
"Benno Lossin" <lossin@kernel.org>,
"Andreas Hindborg" <a.hindborg@kernel.org>,
"Alice Ryhl" <aliceryhl@google.com>,
"Trevor Gross" <tmgross@umich.edu>,
"Danilo Krummrich" <dakr@kernel.org>,
"Will Deacon" <will@kernel.org>,
"Peter Zijlstra" <peterz@infradead.org>,
"Mark Rutland" <mark.rutland@arm.com>,
"Wedson Almeida Filho" <wedsonaf@gmail.com>,
"Viresh Kumar" <viresh.kumar@linaro.org>,
"Lyude Paul" <lyude@redhat.com>, "Ingo Molnar" <mingo@kernel.org>,
"Mitchell Levy" <levymitchell0@gmail.com>,
"Paul E. McKenney" <paulmck@kernel.org>,
"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
"Linus Torvalds" <torvalds@linux-foundation.org>,
"Thomas Gleixner" <tglx@linutronix.de>
Subject: [PATCH v4 08/10] rust: sync: atomic: Add Atomic<{usize,isize}>
Date: Mon, 9 Jun 2025 15:46:13 -0700 [thread overview]
Message-ID: <20250609224615.27061-9-boqun.feng@gmail.com> (raw)
In-Reply-To: <20250609224615.27061-1-boqun.feng@gmail.com>
Add generic atomic support for `usize` and `isize`. Note that instead of
mapping directly to `atomic_long_t`, the represention type
(`AllowAtomic::Repr`) is selected based on CONFIG_64BIT. This reduces
the necessarity of creating `atomic_long_*` helpers, which could save
the binary size of kernel if inline helpers are not available.
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
---
rust/kernel/sync/atomic.rs | 54 ++++++++++++++++++++++++++++++++++++--
1 file changed, 52 insertions(+), 2 deletions(-)
diff --git a/rust/kernel/sync/atomic.rs b/rust/kernel/sync/atomic.rs
index 9039591b4d46..e36431f0b42c 100644
--- a/rust/kernel/sync/atomic.rs
+++ b/rust/kernel/sync/atomic.rs
@@ -65,6 +65,56 @@ fn delta_into_repr(d: Self::Delta) -> Self::Repr {
}
}
+// SAFETY: `usize` has the same size and the alignment as `i64` for 64bit and the same as `i32` for
+// 32bit.
+unsafe impl generic::AllowAtomic for usize {
+ #[cfg(CONFIG_64BIT)]
+ type Repr = i64;
+ #[cfg(not(CONFIG_64BIT))]
+ type Repr = i32;
+
+ fn into_repr(self) -> Self::Repr {
+ self as Self::Repr
+ }
+
+ fn from_repr(repr: Self::Repr) -> Self {
+ repr as Self
+ }
+}
+
+impl generic::AllowAtomicArithmetic for usize {
+ type Delta = usize;
+
+ fn delta_into_repr(d: Self::Delta) -> Self::Repr {
+ d as Self::Repr
+ }
+}
+
+// SAFETY: `isize` has the same size and the alignment as `i64` for 64bit and the same as `i32` for
+// 32bit.
+unsafe impl generic::AllowAtomic for isize {
+ #[cfg(CONFIG_64BIT)]
+ type Repr = i64;
+ #[cfg(not(CONFIG_64BIT))]
+ type Repr = i32;
+
+ fn into_repr(self) -> Self::Repr {
+ self as Self::Repr
+ }
+
+ fn from_repr(repr: Self::Repr) -> Self {
+ repr as Self
+ }
+}
+
+impl generic::AllowAtomicArithmetic for isize {
+ type Delta = isize;
+
+ fn delta_into_repr(d: Self::Delta) -> Self::Repr {
+ d as Self::Repr
+ }
+}
+
use crate::macros::kunit_tests;
#[kunit_tests(rust_atomics)]
@@ -84,7 +134,7 @@ macro_rules! for_each_type {
#[test]
fn atomic_basic_tests() {
- for_each_type!(42 in [i32, i64, u32, u64] |v| {
+ for_each_type!(42 in [i32, i64, u32, u64, isize, usize] |v| {
let x = Atomic::new(v);
assert_eq!(v, x.load(Relaxed));
@@ -93,7 +143,7 @@ fn atomic_basic_tests() {
#[test]
fn atomic_arithmetic_tests() {
- for_each_type!(42 in [i32, i64, u32, u64] |v| {
+ for_each_type!(42 in [i32, i64, u32, u64, isize, usize] |v| {
let x = Atomic::new(v);
assert_eq!(v, x.fetch_add(12, Full));
--
2.39.5 (Apple Git-154)
next prev parent reply other threads:[~2025-06-09 22:46 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-06-09 22:46 [PATCH v4 00/10] LKMM generic atomics in Rust Boqun Feng
2025-06-09 22:46 ` [PATCH v4 01/10] rust: Introduce atomic API helpers Boqun Feng
2025-06-09 22:46 ` [PATCH v4 02/10] rust: sync: Add basic atomic operation mapping framework Boqun Feng
2025-06-09 22:46 ` [PATCH v4 03/10] rust: sync: atomic: Add ordering annotation types Boqun Feng
2025-06-10 9:07 ` Benno Lossin
2025-06-10 17:30 ` Boqun Feng
2025-06-10 17:58 ` Boqun Feng
2025-06-10 18:53 ` Boqun Feng
2025-06-11 6:40 ` Benno Lossin
2025-06-09 22:46 ` [PATCH v4 04/10] rust: sync: atomic: Add generic atomics Boqun Feng
2025-06-09 22:46 ` [PATCH v4 05/10] rust: sync: atomic: Add atomic {cmp,}xchg operations Boqun Feng
2025-06-09 22:46 ` [PATCH v4 06/10] rust: sync: atomic: Add the framework of arithmetic operations Boqun Feng
2025-06-09 22:46 ` [PATCH v4 07/10] rust: sync: atomic: Add Atomic<u{32,64}> Boqun Feng
2025-06-09 22:46 ` Boqun Feng [this message]
2025-06-09 22:46 ` [PATCH v4 09/10] rust: sync: atomic: Add Atomic<*mut T> Boqun Feng
2025-06-09 22:46 ` [PATCH v4 10/10] rust: sync: Add memory barriers Boqun Feng
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