linux-kernel - [PATCH 22/36] rust: list: Switch to kernel::sync atomic primitives

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Message-ID: <20260111120209.6133-20-boqun.feng@gmail.com>
Date: Sun, 11 Jan 2026 20:01:55 +0800
From: Boqun Feng <boqun.feng@...il.com>
To: "Peter Zijlstra" <peterz@...radead.org>,
	"Ingo Molnar" <mingo@...nel.org>
Cc: rust-for-linux@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	"Will Deacon" <will@...nel.org>,
	"Mark Rutland" <mark.rutland@....com>,
	"Thomas Gleixner" <tglx@...utronix.de>,
	"Miguel Ojeda" <ojeda@...nel.org>,
	"Gary Guo" <gary@...yguo.net>,
	"Alice Ryhl" <aliceryhl@...gle.com>,
	"Andreas Hindborg" <a.hindborg@...nel.org>,
	"Benno Lossin" <lossin@...nel.org>,
	"Danilo Krummrich" <dakr@...nel.org>,
	FUJITA Tomonori <fujita.tomonori@...il.com>,
	Boqun Feng <boqun.feng@...il.com>
Subject: [PATCH 22/36] rust: list: Switch to kernel::sync atomic primitives

From: FUJITA Tomonori <fujita.tomonori@...il.com>

Convert uses of `AtomicBool` to `Atomic<bool>`.

Note that the compare_exchange migration simplifies to
`try_cmpxchg()`, since `try_cmpxchg()` provides relaxed ordering on
failure, making the explicit failure ordering unnecessary.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@...il.com>
Reviewed-by: Alice Ryhl <aliceryhl@...gle.com>
Signed-off-by: Boqun Feng <boqun.feng@...il.com>
Link: https://patch.msgid.link/20251230093718.1852322-3-fujita.tomonori@gmail.com
---
 rust/kernel/list/arc.rs | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/rust/kernel/list/arc.rs b/rust/kernel/list/arc.rs
index d92bcf665c89..2282f33913ee 100644
--- a/rust/kernel/list/arc.rs
+++ b/rust/kernel/list/arc.rs
@@ -6,11 +6,11 @@
 
 use crate::alloc::{AllocError, Flags};
 use crate::prelude::*;
+use crate::sync::atomic::{ordering, Atomic};
 use crate::sync::{Arc, ArcBorrow, UniqueArc};
 use core::marker::PhantomPinned;
 use core::ops::Deref;
 use core::pin::Pin;
-use core::sync::atomic::{AtomicBool, Ordering};
 
 /// Declares that this type has some way to ensure that there is exactly one `ListArc` instance for
 /// this id.
@@ -469,7 +469,7 @@ impl<T, U, const ID: u64> core::ops::DispatchFromDyn<ListArc<U, ID>> for ListArc
 /// If the boolean is `false`, then there is no [`ListArc`] for this value.
 #[repr(transparent)]
 pub struct AtomicTracker<const ID: u64 = 0> {
-    inner: AtomicBool,
+    inner: Atomic<bool>,
     // This value needs to be pinned to justify the INVARIANT: comment in `AtomicTracker::new`.
     _pin: PhantomPinned,
 }
@@ -480,12 +480,12 @@ pub fn new() -> impl PinInit<Self> {
         // INVARIANT: Pin-init initializers can't be used on an existing `Arc`, so this value will
         // not be constructed in an `Arc` that already has a `ListArc`.
         Self {
-            inner: AtomicBool::new(false),
+            inner: Atomic::new(false),
             _pin: PhantomPinned,
         }
     }
 
-    fn project_inner(self: Pin<&mut Self>) -> &mut AtomicBool {
+    fn project_inner(self: Pin<&mut Self>) -> &mut Atomic<bool> {
         // SAFETY: The `inner` field is not structurally pinned, so we may obtain a mutable
         // reference to it even if we only have a pinned reference to `self`.
         unsafe { &mut Pin::into_inner_unchecked(self).inner }
@@ -500,7 +500,7 @@ unsafe fn on_create_list_arc_from_unique(self: Pin<&mut Self>) {
 
     unsafe fn on_drop_list_arc(&self) {
         // INVARIANT: We just dropped a ListArc, so the boolean should be false.
-        self.inner.store(false, Ordering::Release);
+        self.inner.store(false, ordering::Release);
     }
 }
 
@@ -514,8 +514,6 @@ unsafe impl<const ID: u64> TryNewListArc<ID> for AtomicTracker<ID> {
     fn try_new_list_arc(&self) -> bool {
         // INVARIANT: If this method returns true, then the boolean used to be false, and is no
         // longer false, so it is okay for the caller to create a new [`ListArc`].
-        self.inner
-            .compare_exchange(false, true, Ordering::Acquire, Ordering::Relaxed)
-            .is_ok()
+        self.inner.cmpxchg(false, true, ordering::Acquire).is_ok()
     }
 }
-- 
2.51.0