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 8EF5DC7619A for ; Sat, 8 Apr 2023 07:54:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229785AbjDHHyg (ORCPT ); Sat, 8 Apr 2023 03:54:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59762 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230056AbjDHHyQ (ORCPT ); Sat, 8 Apr 2023 03:54:16 -0400 Received: from mail-oo1-xc31.google.com (mail-oo1-xc31.google.com [IPv6:2607:f8b0:4864:20::c31]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0C981EF91; Sat, 8 Apr 2023 00:54:11 -0700 (PDT) Received: by mail-oo1-xc31.google.com with SMTP id g26-20020a4adc9a000000b0053b9059edd5so101132oou.3; Sat, 08 Apr 2023 00:54:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; t=1680940451; 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=wpOoeU4Qo2xSWrP8Zd47XosmBdNzXp8ItY0SM633XWM=; b=XLHoIICN4WFwHuDBqxfKuglpmeOGb0tM/R0Hg70PpgPHdHtnZs4dWSz8OGj0GBvj+w RmXHSyGsBLFukKlZM6mC4tGYngB2/VEOVVrfQwQ/PZG0wJHWUIUOnmxLTXJZh4VgfXIo Yyvy6fBIYsGXtrdawKmHht6TDayR3g4d4zzYewKAmh3JlCuX3A2vLmD51ZkI7bZ6qBB/ vuNBDV0eo1AjVf84FlG6LoZ/hpS+cUGCxF3KLH+roU5FIOV9UnHVCVQSulDOMdWwh+9x pPzsg9DlH1NeuCgqSLRUwLaRnnUNLKQ/xwJX6SIiuK+2mKPy9A8QSm204DTuI4LaZSMQ U0TQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1680940451; 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=wpOoeU4Qo2xSWrP8Zd47XosmBdNzXp8ItY0SM633XWM=; b=LRsH13/nkR9WTA4H447eUIqurpK49UVf3ww1taBd0YL/hhdAZ0wgEmRsH7f05DNZAC Xsw+RGxlRCo26cvpA3+e0Nxt2rl7PBr9reK3tIfeLlDfggYg+l/YSx8SQMGdebGygq+d 8mD+mj/9N4SvEMOP/dKUeZ86mQa4a48Eaa3JDJS0mUyR9E/butChLlk+p+8u3yXzG+zf /6alUKwVOwYYtBeYM+18dRHpPkPuuIqCVtQ4blwDGVS4Iyi6AUlug2hbMEeAZd8zcLHf CUweiNlieRAWs9zpGZYpWO7skT0DEAhRF7EthXT5MsA9q36u1+FR672aPTbfeNHq2PO9 68bw== X-Gm-Message-State: AAQBX9fvgxtk5ZC1g7UOjA4xWXdZkVMx1XzmmlcJr00ogN8mvYdlELc0 Lc+YviD4yhYqdA1LcfMNF6L4GKw/BkQ= X-Google-Smtp-Source: AKy350YrquCOq7bdfdlw3x4MFa6rgRr71bB0aUmra4lMhjkiyi75Bue78/5tsEWXIKUo6utlI4PnZA== X-Received: by 2002:a4a:58cb:0:b0:517:a7d1:9762 with SMTP id f194-20020a4a58cb000000b00517a7d19762mr2437292oob.7.1680940450726; Sat, 08 Apr 2023 00:54:10 -0700 (PDT) Received: from wedsonaf-dev.home.lan ([189.124.190.154]) by smtp.googlemail.com with ESMTPSA id o6-20020a4a9586000000b0051ffe0fe11bsm2435175ooi.6.2023.04.08.00.54.08 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 08 Apr 2023 00:54:10 -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 v3 06/13] rust: lock: add support for `Lock::lock_irqsave` Date: Sat, 8 Apr 2023 04:53:33 -0300 Message-Id: <20230408075340.25237-6-wedsonaf@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230408075340.25237-1-wedsonaf@gmail.com> References: <20230408075340.25237-1-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 v2 -> v3: 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 df43dff5af5c..690429561f0e 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 @@ -111,6 +134,21 @@ 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