From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4648BC761AF for ; Wed, 5 Apr 2023 17:52:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231564AbjDERwS (ORCPT ); Wed, 5 Apr 2023 13:52:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38554 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232079AbjDERwR (ORCPT ); Wed, 5 Apr 2023 13:52:17 -0400 Received: from mail-oi1-x22f.google.com (mail-oi1-x22f.google.com [IPv6:2607:f8b0:4864:20::22f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6CCD065B2; Wed, 5 Apr 2023 10:52:07 -0700 (PDT) Received: by mail-oi1-x22f.google.com with SMTP id b19so27233751oib.7; Wed, 05 Apr 2023 10:52:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; t=1680717127; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=sG++w8NyFtmU3a0MKdVasgEDSXcDlxmofOYd/dEc4Vg=; b=MqTYpyAJ0uiRFQpxjXrrJm0DoawAd2L4V+h9dx2IhPXHokDFQ0nQosHQrSNLNNW3Eo z6vOY/TRmvjtzI7nD3AwKa5mBy6xN/VvLktI8E9nNvDXCz3+qXze8p7iPC58i+w/b0rW 9p22SV0DtBbtIIR3fzf+hccTgSsXyL/zSTXAiwTB/IsjVP/B5GXSdIDlA+AmO95Eoj6q Sa0vO6fEis4pZtAOdFCznr26WIZKeiuBgO4d0djF6daQDx9iNyhlq3glL+VObxTbTCxo RbG3upqiyIosE7AUb3Jj7xmC5ZlygF9XB3nRF2icOXCgN3egsgfWWb2lxxGBzviR+Qbr ZylA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1680717127; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=sG++w8NyFtmU3a0MKdVasgEDSXcDlxmofOYd/dEc4Vg=; b=FzQyGyLQsXhFsa9e8lbdlN8dRloXb5BzP7j320LC76xrszOSrxM030Xift10+jKNoc QWYlGaaDPt54fH2E9++lA2OjgfxXXp2ZeaKH6lSfX+pGSXlLI3Sqj5PRIDSPT8bImoq8 7U+kspqGt7qPY8h03ZFq/aMQsi8p2rkwfBguLgoSczZnpWLx+CDJwvlOnHqKzgDFPWkm PhC65svNUrrAA0eur0iB5GrXYqVpUIXqZHr1a6HuTQCPAGI+Kiy4Su0C8Ju8qZX5OUN4 D9gOd9l1SRBuqj20IzVzdaBA/sUx7KgwJ6CkadRf9WfQxAFtFxWWZXz+MzAkRVGW8jJN Xjfw== X-Gm-Message-State: AAQBX9fSLUGjbgdFTTQrVYpHFBYU/wLaNgcGl0eIgARC96h/w+MxHC/h a4wI87XRZsa3o4MYih1ipZIiObOpFc8= X-Google-Smtp-Source: AKy350aLoVyVPn3feTTFZLJ056HP8gggLDXJWePrtJRPJWhL6GCPiTc2OS03gnKMK29D80yhHJAN1g== X-Received: by 2002:aca:1e0b:0:b0:387:2075:59b with SMTP id m11-20020aca1e0b000000b003872075059bmr2901893oic.24.1680717127067; Wed, 05 Apr 2023 10:52:07 -0700 (PDT) Received: from wedsonaf-dev.home.lan ([189.124.190.154]) by smtp.googlemail.com with ESMTPSA id w185-20020aca62c2000000b003896e31867esm6604045oib.49.2023.04.05.10.52.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 05 Apr 2023 10:52:06 -0700 (PDT) From: Wedson Almeida Filho To: rust-for-linux@vger.kernel.org Cc: Miguel Ojeda , Alex Gaynor , Boqun Feng , Gary Guo , =?UTF-8?q?Bj=C3=B6rn=20Roy=20Baron?= , linux-kernel@vger.kernel.org, Wedson Almeida Filho Subject: [PATCH v2 06/13] rust: lock: add support for `Lock::lock_irqsave` Date: Wed, 5 Apr 2023 14:51:04 -0300 Message-Id: <20230405175111.5974-6-wedsonaf@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230405175111.5974-1-wedsonaf@gmail.com> References: <20230405175111.5974-1-wedsonaf@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: rust-for-linux@vger.kernel.org From: Wedson Almeida Filho This allows locks like spinlocks and raw spinlocks to expose a `lock_irqsave` variant in Rust that corresponds to the C version. Signed-off-by: Wedson Almeida Filho --- v1 -> v2: No changes rust/kernel/sync/lock.rs | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) diff --git a/rust/kernel/sync/lock.rs b/rust/kernel/sync/lock.rs index bca9af2a9a5a..491446c3a074 100644 --- a/rust/kernel/sync/lock.rs +++ b/rust/kernel/sync/lock.rs @@ -57,6 +57,29 @@ pub unsafe trait Backend { unsafe fn unlock(ptr: *mut Self::State, guard_state: &Self::GuardState); } +/// The "backend" of a lock that supports the irq-save variant. +/// +/// # Safety +/// +/// The same requirements wrt mutual exclusion in [`Backend`] apply for acquiring the lock via +/// [`IrqSaveBackend::lock_irqsave`]. +/// +/// Additionally, when [`IrqSaveBackend::lock_irqsave`] is used to acquire the lock, implementers +/// must disable interrupts on lock, and restore interrupt state on unlock. Implementers may use +/// [`Backend::GuardState`] to store state needed to keep track of the interrupt state. +pub unsafe trait IrqSaveBackend: Backend { + /// Acquires the lock, making the caller its owner. + /// + /// Before acquiring the lock, it disables interrupts, and returns the previous interrupt state + /// as its guard state so that the guard can restore it when it is dropped. + /// + /// # Safety + /// + /// Callers must ensure that [`Backend::init`] has been previously called. + #[must_use] + unsafe fn lock_irqsave(ptr: *mut Self::State) -> Self::GuardState; +} + /// A mutual exclusion primitive. /// /// Exposes one of the kernel locking primitives. Which one is exposed depends on the lock banckend @@ -109,6 +132,21 @@ impl Lock { } } +impl Lock { + /// Acquires the lock and gives the caller access to the data protected by it. + /// + /// Before acquiring the lock, it disables interrupts. When the guard is dropped, the interrupt + /// state (either enabled or disabled) is restored to its state before + /// [`lock_irqsave`](Self::lock_irqsave) was called. + pub fn lock_irqsave(&self) -> Guard<'_, T, B> { + // SAFETY: The constructor of the type calls `init`, so the existence of the object proves + // that `init` was called. + let state = unsafe { B::lock_irqsave(self.state.get()) }; + // SAFETY: The lock was just acquired. + unsafe { Guard::new(self, state) } + } +} + /// A lock guard. /// /// Allows mutual exclusion primitives that implement the `Backend` trait to automatically unlock -- 2.34.1