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 5A78F353A8E; Fri, 3 Jul 2026 07:32:18 +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=1783063939; cv=none; b=eQyLey8IUzig79K/AsAsfRS8o/NqksLgkhIHI+pYCdHuF0TwwBzm91X5TYYHkWeBPXhfTD/HmBzZUG9RJzq/VVlozwLlJw91PBWrJXdlap478othile86H1zaLEw12WsfP4qlCWroeG/PkWxa5t7vD0A/3XfX8m+NHt/HHe07N8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783063939; c=relaxed/simple; bh=V/pzrCFV8IdJ56UsCIzwzcykh7+qJbMM3pf8n/QUuYo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=RVrfFx3J3nFEqKBUXEzekEoYplkJ7LYUW5ZRpOP/bsAot+4OL6UlSUFFGWvgr6lX/INDdlbI7/Y+Yt0cL6thjvSUtNkGoxK+OW8SfxEZlHVQEJxN/EeQCmUecZO4tsxxO+KsfW8m4S4CKYdVYmvG/I9GDS32H5UtVjmjj6pi9wc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Us+fRwVn; 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="Us+fRwVn" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F3CE11F00A3A; Fri, 3 Jul 2026 07:32:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1783063938; bh=1zoIAZtdXOviXMtnoJ37cYn19oGrY7Vb57AI0Lnpx5s=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Us+fRwVn+sSB0I9T5c05P0bkcpFrtgiBb8eXoRKEY5KXCdBCp01+FB+mn9SWA44fR dLCAn6wbvXF0K7KR4IEdh2rhm6Vgg04RnmLRECxznWQf40BV5dFuoZHPjMml4TBIjO ObTEoG8hvDSGnnBK8jXXoPKE6CXuWFnfprCF+kOriQHi3dGzBZzcKA/PqwzCeT6Egk cSjQA/1qyQGe4ACpdhzvmBqPc2Ox14Hp5nA56uErYGEua9brLBHOBK5D5gsSA5+rIM +prf2rnq+LsGNvVJzSoj0zocq65PJtyzMWeqUyP/dnjTPXycg6BrLdGYRqzFCbbwA/ W/zkEgTP/mpLQ== 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 , Sumit Semwal , =?UTF-8?q?Christian=20K=C3=B6nig?= , Philipp Stanner , Daniel Almeida , Greg Kroah-Hartman , Asahi Lina , Burak Emir , Lorenzo Stoakes , Joel Fernandes , Alexandre Courbot , Krishna Ketan Rai , Tamir Duberstein , Mirko Adzic , Alistair Francis , =?UTF-8?q?Onur=20=C3=96zkan?= , Shankari Anand 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 Subject: [PATCH v5 3/5] rust: sync: Add abstraction for rcu_barrier() Date: Fri, 3 Jul 2026 09:31:39 +0200 Message-ID: <20260703073141.3962604-5-phasta@kernel.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260703073141.3962604-2-phasta@kernel.org> References: <20260703073141.3962604-2-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 --- 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() }; +} -- 2.54.0