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[103.168.172.201]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-8942e6c9a9dsm107071836d6.43.2026.01.20.03.52.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 20 Jan 2026 03:52:18 -0800 (PST) Received: from phl-compute-05.internal (phl-compute-05.internal [10.202.2.45]) by mailfauth.phl.internal (Postfix) with ESMTP id 8EB16F40068; Tue, 20 Jan 2026 06:52:17 -0500 (EST) Received: from phl-frontend-03 ([10.202.2.162]) by phl-compute-05.internal (MEProxy); Tue, 20 Jan 2026 06:52:17 -0500 X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeefgedrtddtgddugedtfeegucetufdoteggodetrf dotffvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfurfetoffkrfgpnffqhgenuceu rghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmnecujf gurhephffvvefufffkofgjfhgggfestdekredtredttdenucfhrhhomhepuehoqhhunhcu hfgvnhhguceosghoqhhunhdrfhgvnhhgsehgmhgrihhlrdgtohhmqeenucggtffrrghtth gvrhhnpeegleejiedthedvheeggfejveefjeejkefgveffieeujefhueeigfegueehgeeg gfenucevlhhushhtvghrufhiiigvpedtnecurfgrrhgrmhepmhgrihhlfhhrohhmpegsoh hquhhnodhmvghsmhhtphgruhhthhhpvghrshhonhgrlhhithihqdeiledvgeehtdeigedq udejjeekheehhedvqdgsohhquhhnrdhfvghngheppehgmhgrihhlrdgtohhmsehfihigmh gvrdhnrghmvgdpnhgspghrtghpthhtohepvddtpdhmohguvgepshhmthhpohhuthdprhgt phhtthhopehlihhnuhigqdhkvghrnhgvlhesvhhgvghrrdhkvghrnhgvlhdrohhrghdprh gtphhtthhopehruhhsthdqfhhorhdqlhhinhhugiesvhhgvghrrdhkvghrnhgvlhdrohhr ghdprhgtphhtthhopehlihhnuhigqdhfshguvghvvghlsehvghgvrhdrkhgvrhhnvghlrd horhhgpdhrtghpthhtohepkhgrshgrnhdquggvvhesghhoohhglhgvghhrohhuphhsrdgt ohhmpdhrtghpthhtohepfihilhhlsehkvghrnhgvlhdrohhrghdprhgtphhtthhopehpvg htvghriiesihhnfhhrrgguvggrugdrohhrghdprhgtphhtthhopegsohhquhhnrdhfvghn ghesghhmrghilhdrtghomhdprhgtphhtthhopehmrghrkhdrrhhuthhlrghnugesrghrmh drtghomhdprhgtphhtthhopehgrghrhiesghgrrhihghhuohdrnhgvth X-ME-Proxy: Feedback-ID: iad51458e:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Tue, 20 Jan 2026 06:52:16 -0500 (EST) From: Boqun Feng To: linux-kernel@vger.kernel.org, rust-for-linux@vger.kernel.org, linux-fsdevel@vger.kernel.org, kasan-dev@googlegroups.com Cc: Will Deacon , Peter Zijlstra , Boqun Feng , Mark Rutland , Gary Guo , Miguel Ojeda , =?UTF-8?q?Bj=C3=B6rn=20Roy=20Baron?= , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Danilo Krummrich , Elle Rhumsaa , "Paul E. McKenney" , Marco Elver , FUJITA Tomonori Subject: [PATCH 1/2] rust: sync: atomic: Remove bound `T: Sync` for `Atomci::from_ptr()` Date: Tue, 20 Jan 2026 19:52:06 +0800 Message-ID: <20260120115207.55318-2-boqun.feng@gmail.com> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20260120115207.55318-1-boqun.feng@gmail.com> References: <20260120115207.55318-1-boqun.feng@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Originally, `Atomic::from_ptr()` requires `T` being a `Sync` because I thought having the ability to do `from_ptr()` meant multiplle `&Atomic`s shared by different threads, which was identical (or similar) to multiple `&T`s shared by different threads. Hence `T` was required to be `Sync`. However this is not true, since `&Atomic` is not the same at `&T`. Moreover, having this bound makes `Atomic::<*mut T>::from_ptr()` impossible, which is definitely not intended. Therefore remove the `T: Sync` bound. Fixes: 29c32c405e53 ("rust: sync: atomic: Add generic atomics") Signed-off-by: Boqun Feng Reviewed-by: Alice Ryhl Reviewed-by: Gary Guo --- rust/kernel/sync/atomic.rs | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) diff --git a/rust/kernel/sync/atomic.rs b/rust/kernel/sync/atomic.rs index 224bd57da1ab..d49ee45c6eb7 100644 --- a/rust/kernel/sync/atomic.rs +++ b/rust/kernel/sync/atomic.rs @@ -215,10 +215,7 @@ pub const fn new(v: T) -> Self { /// // no data race. /// unsafe { Atomic::from_ptr(foo_a_ptr) }.store(2, Release); /// ``` - pub unsafe fn from_ptr<'a>(ptr: *mut T) -> &'a Self - where - T: Sync, - { + pub unsafe fn from_ptr<'a>(ptr: *mut T) -> &'a Self { // CAST: `T` and `Atomic` have the same size, alignment and bit= validity. // SAFETY: Per function safety requirement, `ptr` is a valid point= er and the object will // live long enough. It's safe to return a `&Atomic` because fu= nction safety requirement --=20 2.51.0