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[103.168.172.201]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-8907710632asm115216876d6.24.2026.01.11.04.03.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 11 Jan 2026 04:03:05 -0800 (PST) Received: from phl-compute-12.internal (phl-compute-12.internal [10.202.2.52]) by mailfauth.phl.internal (Postfix) with ESMTP id 591BDF40068; Sun, 11 Jan 2026 07:03:05 -0500 (EST) Received: from phl-frontend-03 ([10.202.2.162]) by phl-compute-12.internal (MEProxy); Sun, 11 Jan 2026 07:03:05 -0500 X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeefgedrtddtgdduudegheduucetufdoteggodetrf dotffvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfurfetoffkrfgpnffqhgenuceu rghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmnecujf gurhephffvvefufffkofgjfhgggfestdekredtredttdenucfhrhhomhepuehoqhhunhcu hfgvnhhguceosghoqhhunhdrfhgvnhhgsehgmhgrihhlrdgtohhmqeenucggtffrrghtth gvrhhnpeejgeeitefgtdeuieefudefhefhhfdtvdejhedvveduvdehgeehuefhgfeiteff vdenucffohhmrghinheprhhushhtqdhlrghnghdrohhrghdpmhhsghhiugdrlhhinhhkne cuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehmrghilhhfrhhomhepsghoqhhu nhdomhgvshhmthhprghuthhhphgvrhhsohhnrghlihhthidqieelvdeghedtieegqdduje ejkeehheehvddqsghoqhhunhdrfhgvnhhgpeepghhmrghilhdrtghomhesfhhigihmvgdr nhgrmhgvpdhnsggprhgtphhtthhopeduhedpmhhouggvpehsmhhtphhouhhtpdhrtghpth htohepphgvthgvrhiisehinhhfrhgruggvrggurdhorhhgpdhrtghpthhtohepmhhinhhg oheskhgvrhhnvghlrdhorhhgpdhrtghpthhtoheprhhushhtqdhfohhrqdhlihhnuhigse hvghgvrhdrkhgvrhhnvghlrdhorhhgpdhrtghpthhtoheplhhinhhugidqkhgvrhhnvghl sehvghgvrhdrkhgvrhhnvghlrdhorhhgpdhrtghpthhtohepfihilhhlsehkvghrnhgvlh drohhrghdprhgtphhtthhopehmrghrkhdrrhhuthhlrghnugesrghrmhdrtghomhdprhgt phhtthhopehtghhlgieslhhinhhuthhrohhnihigrdguvgdprhgtphhtthhopehojhgvug grsehkvghrnhgvlhdrohhrghdprhgtphhtthhopehgrghrhiesghgrrhihghhuohdrnhgv th X-ME-Proxy: Feedback-ID: iad51458e:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Sun, 11 Jan 2026 07:03:04 -0500 (EST) From: Boqun Feng To: "Peter Zijlstra" , "Ingo Molnar" Cc: rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, "Will Deacon" , "Mark Rutland" , "Thomas Gleixner" , "Miguel Ojeda" , "Gary Guo" , "Alice Ryhl" , "Andreas Hindborg" , "Benno Lossin" , "Danilo Krummrich" , FUJITA Tomonori , Boqun Feng Subject: [PATCH 20/36] rust: sync: atomic: Add atomic bool support via i8 representation Date: Sun, 11 Jan 2026 20:01:53 +0800 Message-ID: <20260111120209.6133-18-boqun.feng@gmail.com> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20260111120209.6133-1-boqun.feng@gmail.com> References: <20260111115808.5702-1-boqun.feng@gmail.com> <20260111120209.6133-1-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: 8bit From: FUJITA Tomonori Add `bool` support, `Atomic` by using `i8` as its underlying representation. Rust specifies that `bool` has size 1 and alignment 1 [1], so it matches `i8` on layout; keep `static_assert!()` checks to enforce this assumption at build time. [boqun: Remove the unnecessary impl AtomicImpl for bool] Link: https://doc.rust-lang.org/reference/types/boolean.html [1] Signed-off-by: FUJITA Tomonori Reviewed-by: Gary Guo Signed-off-by: Boqun Feng Link: https://patch.msgid.link/20260101034922.2020334-2-fujita.tomonori@gmail.com --- rust/kernel/sync/atomic/predefine.rs | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/rust/kernel/sync/atomic/predefine.rs b/rust/kernel/sync/atomic/predefine.rs index 248d26555ccf..3fc99174b086 100644 --- a/rust/kernel/sync/atomic/predefine.rs +++ b/rust/kernel/sync/atomic/predefine.rs @@ -5,6 +5,17 @@ use crate::static_assert; use core::mem::{align_of, size_of}; +// Ensure size and alignment requirements are checked. +static_assert!(size_of::() == size_of::()); +static_assert!(align_of::() == align_of::()); + +// SAFETY: `bool` has the same size and alignment as `i8`, and Rust guarantees that `bool` has +// only two valid bit patterns: 0 (false) and 1 (true). Those are valid `i8` values, so `bool` is +// round-trip transmutable to `i8`. +unsafe impl super::AtomicType for bool { + type Repr = i8; +} + // SAFETY: `i8` has the same size and alignment with itself, and is round-trip transmutable to // itself. unsafe impl super::AtomicType for i8 { -- 2.51.0