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(unknown [17.57.155.37]) by p00-icloudmta-asmtp-us-east-2d-60-percent-15 (Postfix) with ESMTPSA id 4AD9618000A6; Wed, 28 Jan 2026 11:52:19 +0000 (UTC) From: FUJITA Tomonori To: boqun.feng@gmail.com, ojeda@kernel.org, peterz@infradead.org, will@kernel.org Cc: a.hindborg@kernel.org, aliceryhl@google.com, bjorn3_gh@protonmail.com, dakr@kernel.org, gary@garyguo.net, lossin@kernel.org, mark.rutland@arm.com, tmgross@umich.edu, rust-for-linux@vger.kernel.org, FUJITA Tomonori Subject: [PATCH v1 2/2] rust: list: Use AtomicFlag in AtomicTracker Date: Wed, 28 Jan 2026 20:52:00 +0900 Message-ID: <20260128115200.3820113-3-tomo@aliasing.net> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260128115200.3820113-1-tomo@aliasing.net> References: <20260128115200.3820113-1-tomo@aliasing.net> Precedence: bulk X-Mailing-List: rust-for-linux@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwMTI4MDA5NyBTYWx0ZWRfX2ZiWN6M81qqj OGenIdKZ0lH5Qs/g7HbVvACW+/LRo/tn4dRhcwKx//ETQHdmhntDBLwkjFmPoY3A/pQ4wlw+aIG jiqpwVcYw9P/6tK4rNUStyAYDsbc6GjJYVZDOPhicNMl5Goaz/1bVaYfVRaeRTjeiUz63mXgNnU RkBJ4Z8jLLLBI3/r3S2G3zmw8HzvG8mHo6V6c4UCMwgmrheOoGnUfOA/AEDdsZAQlVNtIsnIwZq GPrTrC8q64u+XGx2w4TabU6n6R+ffbOVVywt/k6ajcMvAUHmeRDSOPIKIIHhCrey4ksT7kc/WmR XxqCKVXcxau/2sCsXhWUPLdna3Px4v3ug0m85qwk35z+KCuMv96ChvwULhhaDk= X-Authority-Info-Out: v=2.4 cv=L8kQguT8 c=1 sm=1 tr=0 ts=6979f877 cx=c_apl:c_apl_out:c_pps a=bsP7O+dXZ5uKcj+dsLqiMw==:117 a=bsP7O+dXZ5uKcj+dsLqiMw==:17 a=vUbySO9Y5rIA:10 a=VkNPw1HP01LnGYTKEx00:22 a=pGLkceISAAAA:8 a=_2yia0w1AAAA:8 a=haVVJi4SGN7caT7hu4gA:9 a=4yAS8WwzZ1jAEY03B-5r:22 X-Proofpoint-GUID: j2xR5eht1sJagpVRR1Pht0v0nqGQa1T8 X-Proofpoint-ORIG-GUID: j2xR5eht1sJagpVRR1Pht0v0nqGQa1T8 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.51,FMLib:17.12.100.49 definitions=2026-01-28_02,2026-01-27_03,2025-10-01_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 clxscore=1030 spamscore=0 mlxscore=0 mlxlogscore=959 suspectscore=0 bulkscore=0 lowpriorityscore=0 phishscore=0 adultscore=0 malwarescore=0 classifier=spam authscore=0 adjust=0 reason=mlx scancount=1 engine=8.22.0-2601150000 definitions=main-2601280097 X-JNJ: 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 From: FUJITA Tomonori Make AtomicTracker use AtomicFlag instead of Atomic to avoid slow byte-sized RMWs on architectures that don't support them. Reviewed-by: Gary Guo Signed-off-by: FUJITA Tomonori --- rust/kernel/list/arc.rs | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/rust/kernel/list/arc.rs b/rust/kernel/list/arc.rs index 2282f33913ee..5e84f500a3fe 100644 --- a/rust/kernel/list/arc.rs +++ b/rust/kernel/list/arc.rs @@ -6,7 +6,7 @@ use crate::alloc::{AllocError, Flags}; use crate::prelude::*; -use crate::sync::atomic::{ordering, Atomic}; +use crate::sync::atomic::{ordering, AtomicFlag}; use crate::sync::{Arc, ArcBorrow, UniqueArc}; use core::marker::PhantomPinned; use core::ops::Deref; @@ -469,7 +469,7 @@ impl core::ops::DispatchFromDyn> for ListArc /// If the boolean is `false`, then there is no [`ListArc`] for this value. #[repr(transparent)] pub struct AtomicTracker { - inner: Atomic, + inner: AtomicFlag, // 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 { // 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: Atomic::new(false), + inner: AtomicFlag::new(false), _pin: PhantomPinned, } } - fn project_inner(self: Pin<&mut Self>) -> &mut Atomic { + fn project_inner(self: Pin<&mut Self>) -> &mut AtomicFlag { // 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 } -- 2.43.0