From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5F4072D46CE; Wed, 5 Aug 2026 15:02:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785942124; cv=none; b=uKddV9d2nl2gkAEa3vHdrB4xH3HxYolcqCAitJbgkZHaEcvozUU3HZcqyPj+L/B0L16LAknoM//jtcdVdbcszfFBSAwOK44WbhyIQvcznwOTUt10zmAdc429YbeWiE8WVw/JMIR29VrJVTOQfqJ+j/1Lv1FOcjXLFhql4Fsm7js= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785942124; c=relaxed/simple; bh=YOlv3o40GyVVy99CqrmV5kA8RFAg585fD7edIGWhAR8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=fXZ/LfTF8cHiC5QEgNfbXjSwwOz56DtsXj3kCzKt4ubpdhUwSY1wVGm8bvkwr2cvy9mt7lw5et99p98xkli86Zchgm76J+8zOCuKkKZl+yhheFd9mx00iErlHqW/O1M7xLFUC0l7vp0QClt7L4OQ3akGG5JO3YzQu3SCq+v6F5Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=GiPWknGk; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="GiPWknGk" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 272791F00A3A; Wed, 5 Aug 2026 15:01:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785942123; bh=ES4LoSb21zgaO4ykRP24VmWuxpdtjPaJPxGZBbKvNvM=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=GiPWknGkRCtuMRgROKHnONNIBdarVWNcK71u2CbBh0K0HUWT3SqWuQ6mpA8CpNzhH /9PHlVnh6piykDZOXABoZb9J+iVuNw8eOwRDV+DdMuN+Y3KATX9qHyBCc3stng8WfI KJMPb04A4EL0OyFWEiGZVvOUe15PBIZ58cA6iwnVQm0KluzPZwBGoOZoNDT9J1cVDe rR1wZJk0yIb8B+aP1hX7aCpTo5KYIa06cZKlC4onZG0SKN49qh9w2tLZ+ADSTrPn6k B4uqxf4ggiBqoPcCxDdeS2bVq9EShUOqCyyGVFBga7U5EtnQoG6gC+BE/iW8yU5+Bx BEuVzQv/me1Xw== From: Philipp Stanner To: Miguel Ojeda , Boqun Feng , Gary Guo , =?UTF-8?q?Bj=C3=B6rn=20Roy=20Baron?= , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Danilo Krummrich , Daniel Almeida , Tamir Duberstein , Alexandre Courbot , =?UTF-8?q?Onur=20=C3=96zkan?= , Sumit Semwal , =?UTF-8?q?Christian=20K=C3=B6nig?= , Philipp Stanner , Lyude Paul , "Paul E. McKenney" , Frederic Weisbecker , Neeraj Upadhyay , Joel Fernandes , Josh Triplett , Uladzislau Rezki , Steven Rostedt , Mathieu Desnoyers , Lai Jiangshan , Zqiang , Greg Kroah-Hartman , Asahi Lina , Burak Emir , Lorenzo Stoakes , FUJITA Tomonori , Eliot Courtney , Mirko Adzic , Timur Tabi , Daniel del Castillo , Boris Brezillon Cc: linux-kernel@vger.kernel.org, rust-for-linux@vger.kernel.org, linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, rcu@vger.kernel.org Subject: [PATCH v9 3/5] rust: sync: Add abstraction for rcu_barrier() Date: Wed, 5 Aug 2026 16:59:45 +0200 Message-ID: <20260805145949.938505-5-phasta@kernel.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260805145949.938505-2-phasta@kernel.org> References: <20260805145949.938505-2-phasta@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit rcu_barrier() is a frequently used C function which is always safe to be called. Add a safe abstraction for rcu_barrier(). Signed-off-by: Philipp Stanner Tested-by: Daniel Almeida --- rust/kernel/sync/rcu.rs | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/rust/kernel/sync/rcu.rs b/rust/kernel/sync/rcu.rs index a32bef6e490b..7031ca5d2473 100644 --- a/rust/kernel/sync/rcu.rs +++ b/rust/kernel/sync/rcu.rs @@ -50,3 +50,23 @@ fn drop(&mut self) { pub fn read_lock() -> Guard { Guard::new() } + +/// Wait until all in-flight call_rcu() callbacks complete. +/// +/// Note that this primitive does not necessarily wait for an RCU grace period +/// to complete. For example, if there are no RCU callbacks queued anywhere +/// in the system, then rcu_barrier() is within its rights to return +/// immediately, without waiting for anything, much less an RCU grace period. +/// In fact, rcu_barrier() will normally not result in any RCU grace periods +/// beyond those that were already destined to be executed. +/// +/// In kernels built with CONFIG_RCU_LAZY=y, this function also hurries all +/// pending lazy RCU callbacks. +/// +/// Note that this is one of the RCU primitives which must not be called in +/// atomic context. +#[inline] +pub fn rcu_barrier() { + // SAFETY: `rcu_barrier()` is always safe to be called. It just might wait for a grace period. + unsafe { bindings::rcu_barrier() }; +} -- 2.55.0