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[103.168.172.201]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-6d35415a640sm15713376d6.89.2024.10.31.23.04.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 31 Oct 2024 23:04:09 -0700 (PDT) Received: from phl-compute-04.internal (phl-compute-04.phl.internal [10.202.2.44]) by mailfauth.phl.internal (Postfix) with ESMTP id 7765D1200043; Fri, 1 Nov 2024 02:04:09 -0400 (EDT) Received: from phl-mailfrontend-02 ([10.202.2.163]) by phl-compute-04.internal (MEProxy); Fri, 01 Nov 2024 02:04:09 -0400 X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeeftddrvdekkedgkeekucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdggtfgfnhhsuhgsshgtrhhisggvpdfu rfetoffkrfgpnffqhgenuceurghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnh htshculddquddttddmnecujfgurhephffvvefufffkofgjfhgggfestdekredtredttden ucfhrhhomhepuehoqhhunhcuhfgvnhhguceosghoqhhunhdrfhgvnhhgsehgmhgrihhlrd gtohhmqeenucggtffrrghtthgvrhhnpeegleejiedthedvheeggfejveefjeejkefgveff ieeujefhueeigfegueehgeeggfenucevlhhushhtvghrufhiiigvpedtnecurfgrrhgrmh epmhgrihhlfhhrohhmpegsohhquhhnodhmvghsmhhtphgruhhthhhpvghrshhonhgrlhhi thihqdeiledvgeehtdeigedqudejjeekheehhedvqdgsohhquhhnrdhfvghngheppehgmh grihhlrdgtohhmsehfihigmhgvrdhnrghmvgdpnhgspghrtghpthhtohepheekpdhmohgu vgepshhmthhpohhuthdprhgtphhtthhopehruhhsthdqfhhorhdqlhhinhhugiesvhhgvg hrrdhkvghrnhgvlhdrohhrghdprhgtphhtthhopehrtghusehvghgvrhdrkhgvrhhnvghl rdhorhhgpdhrtghpthhtoheplhhinhhugidqkhgvrhhnvghlsehvghgvrhdrkhgvrhhnvg hlrdhorhhgpdhrtghpthhtoheplhhinhhugidqrghrtghhsehvghgvrhdrkhgvrhhnvghl rdhorhhgpdhrtghpthhtoheplhhlvhhmsehlihhsthhsrdhlihhnuhigrdguvghvpdhrtg hpthhtoheplhhkmhhmsehlihhsthhsrdhlihhnuhigrdguvghvpdhrtghpthhtohepohhj vggurgeskhgvrhhnvghlrdhorhhgpdhrtghpthhtoheprghlvgigrdhgrgihnhhorhesgh hmrghilhdrtghomhdprhgtphhtthhopeifvggushhonhgrfhesghhmrghilhdrtghomh X-ME-Proxy: Feedback-ID: iad51458e:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Fri, 1 Nov 2024 02:04:08 -0400 (EDT) From: Boqun Feng To: rust-for-linux@vger.kernel.org, rcu@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, llvm@lists.linux.dev, lkmm@lists.linux.dev Cc: Miguel Ojeda , Alex Gaynor , Wedson Almeida Filho , Boqun Feng , Gary Guo , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , Benno Lossin , Andreas Hindborg , Alice Ryhl , Alan Stern , Andrea Parri , Will Deacon , Peter Zijlstra , Nicholas Piggin , David Howells , Jade Alglave , Luc Maranget , "Paul E. McKenney" , Akira Yokosawa , Daniel Lustig , Joel Fernandes , Nathan Chancellor , Nick Desaulniers , kent.overstreet@gmail.com, Greg Kroah-Hartman , elver@google.com, Mark Rutland , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Catalin Marinas , torvalds@linux-foundation.org, linux-arm-kernel@lists.infradead.org, linux-fsdevel@vger.kernel.org, Trevor Gross , dakr@redhat.com, Frederic Weisbecker , Neeraj Upadhyay , Josh Triplett , Uladzislau Rezki , Steven Rostedt , Mathieu Desnoyers , Lai Jiangshan , Zqiang , Paul Walmsley , Palmer Dabbelt , Albert Ou , linux-riscv@lists.infradead.org, Danilo Krummrich Subject: [RFC v2 12/13] rust: add rcu abstraction Date: Thu, 31 Oct 2024 23:02:35 -0700 Message-ID: <20241101060237.1185533-13-boqun.feng@gmail.com> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20241101060237.1185533-1-boqun.feng@gmail.com> References: <20241101060237.1185533-1-boqun.feng@gmail.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Wedson Almeida Filho Add a simple abstraction to guard critical code sections with an rcu read lock. Signed-off-by: Wedson Almeida Filho Signed-off-by: Danilo Krummrich --- rust/helpers/helpers.c | 1 + rust/helpers/rcu.c | 13 +++++++++++ rust/kernel/sync.rs | 1 + rust/kernel/sync/rcu.rs | 52 +++++++++++++++++++++++++++++++++++++++++ 4 files changed, 67 insertions(+) create mode 100644 rust/helpers/rcu.c create mode 100644 rust/kernel/sync/rcu.rs diff --git a/rust/helpers/helpers.c b/rust/helpers/helpers.c index f4a94833b29d..65951245879f 100644 --- a/rust/helpers/helpers.c +++ b/rust/helpers/helpers.c @@ -18,6 +18,7 @@ #include "mutex.c" #include "page.c" #include "rbtree.c" +#include "rcu.c" #include "refcount.c" #include "signal.c" #include "slab.c" diff --git a/rust/helpers/rcu.c b/rust/helpers/rcu.c new file mode 100644 index 000000000000..f1cec6583513 --- /dev/null +++ b/rust/helpers/rcu.c @@ -0,0 +1,13 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include + +void rust_helper_rcu_read_lock(void) +{ + rcu_read_lock(); +} + +void rust_helper_rcu_read_unlock(void) +{ + rcu_read_unlock(); +} diff --git a/rust/kernel/sync.rs b/rust/kernel/sync.rs index 0d0b19441ae8..f5a413e1ce30 100644 --- a/rust/kernel/sync.rs +++ b/rust/kernel/sync.rs @@ -13,6 +13,7 @@ mod condvar; pub mod lock; mod locked_by; +pub mod rcu; pub use arc::{Arc, ArcBorrow, UniqueArc}; pub use condvar::{new_condvar, CondVar, CondVarTimeoutResult}; diff --git a/rust/kernel/sync/rcu.rs b/rust/kernel/sync/rcu.rs new file mode 100644 index 000000000000..5a35495f69a4 --- /dev/null +++ b/rust/kernel/sync/rcu.rs @@ -0,0 +1,52 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! RCU support. +//! +//! C header: [`include/linux/rcupdate.h`](srctree/include/linux/rcupdate.h) + +use crate::bindings; +use core::marker::PhantomData; + +/// Evidence that the RCU read side lock is held on the current thread/CPU. +/// +/// The type is explicitly not `Send` because this property is per-thread/CPU. +/// +/// # Invariants +/// +/// The RCU read side lock is actually held while instances of this guard exist. +pub struct Guard { + _not_send: PhantomData<*mut ()>, +} + +impl Guard { + /// Acquires the RCU read side lock and returns a guard. + pub fn new() -> Self { + // SAFETY: An FFI call with no additional requirements. + unsafe { bindings::rcu_read_lock() }; + // INVARIANT: The RCU read side lock was just acquired above. + Self { + _not_send: PhantomData, + } + } + + /// Explicitly releases the RCU read side lock. + pub fn unlock(self) {} +} + +impl Default for Guard { + fn default() -> Self { + Self::new() + } +} + +impl Drop for Guard { + fn drop(&mut self) { + // SAFETY: By the type invariants, the rcu read side is locked, so it is ok to unlock it. + unsafe { bindings::rcu_read_unlock() }; + } +} + +/// Acquires the RCU read side lock. +pub fn read_lock() -> Guard { + Guard::new() +}