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 A0BE839DBF7; Fri, 31 Jul 2026 08:05:08 +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=1785485109; cv=none; b=hH4+GqvNycagzu6apvJJerncvUlyJoMVf+NLuf9xdumtUVK9f4bFcDJ4IW/VorsmibwQ327tNY1Qogl9d8ZYxF+NeKiO5HLrfnM8iHfsj0BD7aAOCsGYi2ROsty44bOCzq9w5U06xTjkUvapAuv2D6R2yF6LJBL7lVecSj9NnNM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785485109; c=relaxed/simple; bh=YOlv3o40GyVVy99CqrmV5kA8RFAg585fD7edIGWhAR8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ucC799MRB+lZLsH9ZjGkWjfMat0Mk3fPpjQrCX5RUae2nnVBObUfFBb74pfZEojw9R7G9qyrtry/R5SuIj8JYzEyp2T0AAi43NJThTtoUexWKJOMAPKPJb3fIogmq5PSVhdLJ4clj2F+brg47aki6TCW61VUgCDMs7aiNae3Rjg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=IQogpFwC; 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="IQogpFwC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A792B1F00A3A; Fri, 31 Jul 2026 08:04:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785485108; bh=ES4LoSb21zgaO4ykRP24VmWuxpdtjPaJPxGZBbKvNvM=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=IQogpFwC7c6+zV26KvNH+4Yx9OhwqR/Zh+fW/JMV89JiwrcoyqGs7hkmELkJCGzxw Bz9S4C/SVxUGKS428XPPVTMv3FxBNrA3NbZ935zQgHwYb/Qn6kjkjftFlZVMAThfQB iKyRXwJFmxFwViL5XuDRZIhW6KII9ejWh2cFN6HBbV97gSbmn4FJGrbEhBuA220MwH 3cUirihYQEs3M63oQ3ap0quw9cfI7bHe1iF+VjvLDHiFO0WbyQk2w0cf9YAopDPMv5 56YptaBBJKwK2qKaUFss/L3pcpiwA4XnMaCvDiqeL5lrYdTsN7luNRnW+Z++8yzl8q bhQrnw3bK3phw== 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 v8 3/5] rust: sync: Add abstraction for rcu_barrier() Date: Fri, 31 Jul 2026 10:04:08 +0200 Message-ID: <20260731080411.848772-5-phasta@kernel.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260731080411.848772-2-phasta@kernel.org> References: <20260731080411.848772-2-phasta@kernel.org> Precedence: bulk X-Mailing-List: rust-for-linux@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