From patchwork Fri Oct 4 22:01:38 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mitchell Levy via B4 Relay X-Patchwork-Id: 13823043 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 8236A231CAD; Fri, 4 Oct 2024 22:02:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728079320; cv=none; b=hWBCYqqf5UU2s/yByZ6rW5UQM/+ybQpM4YanHVLiPwvn+95ka7r4K1S0OO4Khavt0LT/iLqa6xp/Mv666KAA/FYGuAX9NDXZB+kslImri4jMKEYOKAwSadOY5aMK0K8AbmrR/COKI0Lx36UkYjDdBamnFcMwG3f9oKIVpIVgBns= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728079320; c=relaxed/simple; bh=MhJNA96GzFeBg9a6LYM830UHrSoHd405+L5yke1y9rE=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=Ds+VrmkwxwDSGc9icM8XMg6SyWteRkpvM2J6csOE7mr9ORS6rbBn7IS+sU4wCOPcWbcYE4zWAbvTbO0tWYNlm8wnvGDqBqZXNJYu9fEabOpbXJMUXPSTj230P2q1Hnulyjt4BIsp3yjSTMWFFb+uF+RHjc2tUh6fv3q1IieTci4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=PClPP3oH; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="PClPP3oH" Received: by smtp.kernel.org (Postfix) with ESMTPS id 57C17C4CECE; Fri, 4 Oct 2024 22:02:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1728079320; bh=MhJNA96GzFeBg9a6LYM830UHrSoHd405+L5yke1y9rE=; h=From:Date:Subject:References:In-Reply-To:To:Cc:Reply-To:From; b=PClPP3oHEke17anFGzi/uawGZRH7vcpmnaeepa0cCP9UWc8gvpkN7MnjfAn4uVnXs Rx4bPvGxSjw+tyv1Om3XOubWIDI7f/aXdwfwCVbp1AdyTW80pPIRAwyPJFNkYrluid nNwMuf+nUQHaW4QaDSWKDfnr998qCUcrfuDM1gy8u0Q+z3tQ2woPMjPJtIlKq7K1YX bVC75lOs6l9173K8zE93DHFNTq0Vx2e8da/K+G1Ey49vrG9iGn5iAkI+YClXBnSiGd b17MxnBZO0xyI9QO1bNms6QQWVsvnq6fWnPcwviqr2DLDlrZ8/u4RitS5oBSPNQ3F1 xGqrpiH4+pgGw== Received: from aws-us-west-2-korg-lkml-1.web.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.lore.kernel.org (Postfix) with ESMTP id 45BBDCF8862; Fri, 4 Oct 2024 22:02:00 +0000 (UTC) From: Mitchell Levy via B4 Relay Date: Fri, 04 Oct 2024 15:01:38 -0700 Subject: [PATCH 2/2] rust: lockdep: Use Pin for all LockClassKey usages Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20241004-rust-lockdep-v1-2-e9a5c45721fc@gmail.com> References: <20241004-rust-lockdep-v1-0-e9a5c45721fc@gmail.com> In-Reply-To: <20241004-rust-lockdep-v1-0-e9a5c45721fc@gmail.com> To: Boqun Feng , Miguel Ojeda , Alex Gaynor , Wedson Almeida Filho , Gary Guo , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , Benno Lossin , Alice Ryhl , Trevor Gross , Andreas Hindborg , Andreas Hindborg Cc: linux-block@vger.kernel.org, rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, Mitchell Levy X-Mailer: b4 0.14.0 X-Developer-Signature: v=1; a=ed25519-sha256; t=1728079319; l=6324; i=levymitchell0@gmail.com; s=20240719; h=from:subject:message-id; bh=egblrpL7foe9PRdbj/s3OB75zKKFl+jmHi9rcTsQviA=; b=LdiL3W4op5Qu1coC1Ds9URaXOy062w9QiB15UUnMDuMQjAyH3+2kMrnlBzksDqKylGYFr18Ti nqFq0B0wN48AlL1Atuu3qY0QTiQ/I3HHVbVixZD/5GBoVGQB8BqFDhS X-Developer-Key: i=levymitchell0@gmail.com; a=ed25519; pk=n6kBmUnb+UNmjVkTnDwrLwTJAEKUfs2e8E+MFPZI93E= X-Endpoint-Received: by B4 Relay for levymitchell0@gmail.com/20240719 with auth_id=188 X-Original-From: Mitchell Levy Reply-To: levymitchell0@gmail.com From: Mitchell Levy Reintroduce dynamically-allocated LockClassKeys such that they are automatically (de)registered. Require that all usages of LockClassKeys ensure that they are Pin'd. Link: https://lore.kernel.org/rust-for-linux/20240815074519.2684107-1-nmi@metaspace.dk/ Suggested-by: Benno Lossin Suggested-by: Boqun Feng Signed-off-by: Mitchell Levy --- rust/helpers/helpers.c | 1 + rust/helpers/sync.c | 13 +++++++++++++ rust/kernel/sync.rs | 30 +++++++++++++++++++++++++++--- rust/kernel/sync/condvar.rs | 11 +++++++---- rust/kernel/sync/lock.rs | 4 ++-- rust/kernel/workqueue.rs | 2 +- 6 files changed, 51 insertions(+), 10 deletions(-) diff --git a/rust/helpers/helpers.c b/rust/helpers/helpers.c index 30f40149f3a9..2e8a2abfca33 100644 --- a/rust/helpers/helpers.c +++ b/rust/helpers/helpers.c @@ -20,6 +20,7 @@ #include "signal.c" #include "slab.c" #include "spinlock.c" +#include "sync.c" #include "task.c" #include "uaccess.c" #include "wait.c" diff --git a/rust/helpers/sync.c b/rust/helpers/sync.c new file mode 100644 index 000000000000..ff7e68b48810 --- /dev/null +++ b/rust/helpers/sync.c @@ -0,0 +1,13 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include + +void rust_helper_lockdep_register_key(struct lock_class_key *k) +{ + lockdep_register_key(k); +} + +void rust_helper_lockdep_unregister_key(struct lock_class_key *k) +{ + lockdep_unregister_key(k); +} diff --git a/rust/kernel/sync.rs b/rust/kernel/sync.rs index d270db9b9894..3903573143b3 100644 --- a/rust/kernel/sync.rs +++ b/rust/kernel/sync.rs @@ -5,6 +5,8 @@ //! This module contains the kernel APIs related to synchronisation that have been ported or //! wrapped for usage by Rust code in the kernel. +use crate::pin_init; +use crate::prelude::*; use crate::types::Opaque; mod arc; @@ -20,15 +22,35 @@ /// Represents a lockdep class. It's a wrapper around C's `lock_class_key`. #[repr(transparent)] -pub struct LockClassKey(Opaque); +#[pin_data(PinnedDrop)] +pub struct LockClassKey { + #[pin] + inner: Opaque, +} // SAFETY: `bindings::lock_class_key` is designed to be used concurrently from multiple threads and // provides its own synchronization. unsafe impl Sync for LockClassKey {} impl LockClassKey { + /// Initializes a dynamically allocated lock class key. In the common case of using a + /// statically allocated lock class key, the static_lock_class! macro should be used instead. + pub fn new_dynamic() -> impl PinInit { + pin_init!(Self { + // SAFETY: lockdep_register_key expects an uninitialized block of memory + inner <- Opaque::ffi_init(|slot| unsafe { bindings::lockdep_register_key(slot) }) + }) + } + pub(crate) fn as_ptr(&self) -> *mut bindings::lock_class_key { - self.0.get() + self.inner.get() + } +} + +#[pinned_drop] +impl PinnedDrop for LockClassKey { + fn drop(self: Pin<&mut Self>) { + unsafe { bindings::lockdep_unregister_key(self.as_ptr()) } } } @@ -37,9 +59,11 @@ pub(crate) fn as_ptr(&self) -> *mut bindings::lock_class_key { #[macro_export] macro_rules! static_lock_class { () => {{ + // SAFETY: lockdep expects uninitialized memory when it's handed a statically allocated + // lock_class_key static CLASS: $crate::sync::LockClassKey = unsafe { ::core::mem::MaybeUninit::uninit().assume_init() }; - &CLASS + $crate::prelude::Pin::static_ref(&CLASS) }}; } diff --git a/rust/kernel/sync/condvar.rs b/rust/kernel/sync/condvar.rs index 2b306afbe56d..0469a9d81b7e 100644 --- a/rust/kernel/sync/condvar.rs +++ b/rust/kernel/sync/condvar.rs @@ -14,9 +14,12 @@ time::Jiffies, types::Opaque, }; -use core::ffi::{c_int, c_long}; -use core::marker::PhantomPinned; -use core::ptr; +use core::{ + ffi::{c_int, c_long}, + marker::PhantomPinned, + pin::Pin, + ptr, +}; use macros::pin_data; /// Creates a [`CondVar`] initialiser with the given name and a newly-created lock class. @@ -102,7 +105,7 @@ unsafe impl Sync for CondVar {} impl CondVar { /// Constructs a new condvar initialiser. - pub fn new(name: &'static CStr, key: &'static LockClassKey) -> impl PinInit { + pub fn new(name: &'static CStr, key: Pin<&'static LockClassKey>) -> impl PinInit { pin_init!(Self { _pin: PhantomPinned, // SAFETY: `slot` is valid while the closure is called and both `name` and `key` have diff --git a/rust/kernel/sync/lock.rs b/rust/kernel/sync/lock.rs index f6c34ca4d819..305c41321369 100644 --- a/rust/kernel/sync/lock.rs +++ b/rust/kernel/sync/lock.rs @@ -7,7 +7,7 @@ use super::LockClassKey; use crate::{init::PinInit, pin_init, str::CStr, types::Opaque, types::ScopeGuard}; -use core::{cell::UnsafeCell, marker::PhantomData, marker::PhantomPinned}; +use core::{cell::UnsafeCell, marker::PhantomData, marker::PhantomPinned, pin::Pin}; use macros::pin_data; pub mod mutex; @@ -106,7 +106,7 @@ unsafe impl Sync for Lock {} impl Lock { /// Constructs a new lock initialiser. - pub fn new(t: T, name: &'static CStr, key: &'static LockClassKey) -> impl PinInit { + pub fn new(t: T, name: &'static CStr, key: Pin<&'static LockClassKey>) -> impl PinInit { pin_init!(Self { data: UnsafeCell::new(t), _pin: PhantomPinned, diff --git a/rust/kernel/workqueue.rs b/rust/kernel/workqueue.rs index 553a5cba2adc..1720a99f53be 100644 --- a/rust/kernel/workqueue.rs +++ b/rust/kernel/workqueue.rs @@ -367,7 +367,7 @@ impl Work { /// Creates a new instance of [`Work`]. #[inline] #[allow(clippy::new_ret_no_self)] - pub fn new(name: &'static CStr, key: &'static LockClassKey) -> impl PinInit + pub fn new(name: &'static CStr, key: Pin<&'static LockClassKey>) -> impl PinInit where T: WorkItem, {