From nobody Thu Oct 31 02:13:53 2024 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 917F9188584 for ; Mon, 16 Sep 2024 21:31:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726522267; cv=none; b=uwjpKw9YFQS8EEypqYF10Fy6HBkM9XG+F0QVPjTq23MI5diS5H8Fp3/7F3qxdqe/j1NBhRTWdEmcVrFJ9+CD1RXdgJCRRSFQEg0HCwnpHr5yBdMXWVEibdwEJd00VQPyKLDnkTbPZQULAi4UNMXyN1lwAiMr+DHlr78xL6f7Va0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726522267; c=relaxed/simple; bh=TfZJbpp9zXEoa+e6StsgG5WDca0qXx/l5uqKk5O50pI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=mLkIRyCgc2Zwd7vSLR/m4l/z9JkrfVHbN0XvwatVTyl2w4XSd8zNsPlBXkhyKjBMnkdQpHIexd1v6pmnl7YCUzk+vYUKjeC8PSVBJhs5pxnnNCZ/GQqahO5HGk4FXAQC3hLJUj0UyB7jCxr9NeME11IpWaiGk6+XSfQayYSk9Ow= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=bqKIMF1U; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="bqKIMF1U" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1726522263; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=ecVEOyaTeumZAX2Umi7O9C03HHNMLFdbxAe12DFyqkw=; b=bqKIMF1UIeCP1hfZbMys+wcbS7d6Z+qpfyE6Ox8W7B62h/udwcCyD/P3oxh8wWpAQrXORf +5PHGTH53tOKsyj5ftiqNDB+b/PTODAgrf/ZUeSo1XzF9xwVFllv8jHLo0Uf1JmyawbYDf c58tXqTiB5Kl4AMUYHEenz3V4RhNDHU= Received: from mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-450-wA-_0SKgO32ivfU7vDK4CQ-1; Mon, 16 Sep 2024 17:31:00 -0400 X-MC-Unique: wA-_0SKgO32ivfU7vDK4CQ-1 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 5F5AA195608C; Mon, 16 Sep 2024 21:30:57 +0000 (UTC) Received: from chopper.redhat.com (unknown [10.22.33.131]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id C723F19560AA; Mon, 16 Sep 2024 21:30:52 +0000 (UTC) From: Lyude Paul To: rust-for-linux@vger.kernel.org Cc: Danilo Krummrich , airlied@redhat.com, Ingo Molnar , Will Deacon , Waiman Long , Peter Zijlstra , Thomas Gleixner , linux-kernel@vger.kernel.org, Benno Lossin , Daniel Almeida , Gary Guo , Miguel Ojeda , Alex Gaynor , Wedson Almeida Filho , Boqun Feng , =?UTF-8?q?Bj=C3=B6rn=20Roy=20Baron?= , Andreas Hindborg , Alice Ryhl , Trevor Gross , Martin Rodriguez Reboredo , Valentin Obst Subject: [PATCH v6 2/3] rust: sync: Introduce lock::Backend::Context Date: Mon, 16 Sep 2024 17:28:05 -0400 Message-ID: <20240916213025.477225-3-lyude@redhat.com> In-Reply-To: <20240916213025.477225-1-lyude@redhat.com> References: <20240916213025.477225-1-lyude@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 Content-Type: text/plain; charset="utf-8" Now that we've introduced an `IrqDisabled` token for marking contexts in which IRQs are disabled, we need a way to be able to pass it to locks that require that IRQs are disabled. In order to continue using the `lock::Backend` type instead of inventing our own thing, we accomplish this by adding the associated Context type, along with a `lock_with()` function that can accept a Context when acquiring a lock. To allow current users of context-less locks to keep using the normal `lock()` method, we take an example from Wedson Almeida Filho's work and add a `where T<'a>: Default` bound to `lock()` so that it can only be called on lock types where the context is simply a placeholder value, then re-implement it through the new `lock_with()` function. Signed-off-by: Lyude Paul Reviewed-by: Benno Lossin Reviewed-by: Daniel Almeida Reviewed-by: Gary Guo Reviewed-by: Boqun Feng Reviewed-by: Trevor Gross --- V3: * Use explicit lifetimes in lock_with() to ensure self and _context have the same lifetime (Benno) * Use () for locks that don't need a Context instead of PhantomData (Benno) V4: * Fix typo (Dirk) --- rust/kernel/sync/lock.rs | 17 +++++++++++++++-- rust/kernel/sync/lock/mutex.rs | 1 + rust/kernel/sync/lock/spinlock.rs | 1 + 3 files changed, 17 insertions(+), 2 deletions(-) diff --git a/rust/kernel/sync/lock.rs b/rust/kernel/sync/lock.rs index d6e9bab114b87..cc39a3dc3f20b 100644 --- a/rust/kernel/sync/lock.rs +++ b/rust/kernel/sync/lock.rs @@ -43,6 +43,9 @@ pub unsafe trait Backend { /// [`unlock`]: Backend::unlock type GuardState; =20 + /// The context which must be provided to acquire the lock. + type Context<'a>; + /// Initialises the lock. /// /// # Safety @@ -125,14 +128,24 @@ pub fn new(t: T, name: &'static CStr, key: &'static L= ockClassKey) -> impl PinIni } =20 impl Lock { - /// Acquires the lock and gives the caller access to the data protecte= d by it. - pub fn lock(&self) -> Guard<'_, T, B> { + /// Acquires the lock with the given context and gives the caller acce= ss to the data protected + /// by it. + pub fn lock_with<'a>(&'a self, _context: B::Context<'a>) -> Guard<'a, = T, B> { // SAFETY: The constructor of the type calls `init`, so the existe= nce of the object proves // that `init` was called. let state =3D unsafe { B::lock(self.state.get()) }; // SAFETY: The lock was just acquired. unsafe { Guard::new(self, state) } } + + /// Acquires the lock and gives the caller access to the data protecte= d by it. + #[inline] + pub fn lock<'a>(&'a self) -> Guard<'a, T, B> + where + B::Context<'a>: Default, + { + self.lock_with(B::Context::default()) + } } =20 /// A lock guard. diff --git a/rust/kernel/sync/lock/mutex.rs b/rust/kernel/sync/lock/mutex.rs index 30632070ee670..7c2c239944931 100644 --- a/rust/kernel/sync/lock/mutex.rs +++ b/rust/kernel/sync/lock/mutex.rs @@ -93,6 +93,7 @@ macro_rules! new_mutex { unsafe impl super::Backend for MutexBackend { type State =3D bindings::mutex; type GuardState =3D (); + type Context<'a> =3D (); =20 unsafe fn init( ptr: *mut Self::State, diff --git a/rust/kernel/sync/lock/spinlock.rs b/rust/kernel/sync/lock/spin= lock.rs index ea5c5bc1ce12e..97d85a5576615 100644 --- a/rust/kernel/sync/lock/spinlock.rs +++ b/rust/kernel/sync/lock/spinlock.rs @@ -92,6 +92,7 @@ macro_rules! new_spinlock { unsafe impl super::Backend for SpinLockBackend { type State =3D bindings::spinlock_t; type GuardState =3D (); + type Context<'a> =3D (); =20 unsafe fn init( ptr: *mut Self::State, --=20 2.46.0