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 B815EC74A5B for ; Thu, 30 Mar 2023 04:41:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230001AbjC3Ele (ORCPT ); Thu, 30 Mar 2023 00:41:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35800 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229929AbjC3ElW (ORCPT ); Thu, 30 Mar 2023 00:41:22 -0400 Received: from mail-ot1-x331.google.com (mail-ot1-x331.google.com [IPv6:2607:f8b0:4864:20::331]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9AD2255B5; Wed, 29 Mar 2023 21:41:08 -0700 (PDT) Received: by mail-ot1-x331.google.com with SMTP id d22-20020a9d5e16000000b0069b5252ced7so9390956oti.13; Wed, 29 Mar 2023 21:41:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; t=1680151268; 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=u/B9dFAeaUqrqqXcKIk+Y/eQ9yVG9iQNTR7il5e9jLs=; b=FBldUjeWmTnMcGDYtqPGJOtkr5qqAbx5XiPvKUIklDArae9Xj9CeCHqo5AgHV6DmJ8 7VYNkFwXjHt4PiCnF+qGoy4piOQ79h/06J07fzF9g5FmSl5EQ8XijZ7ko5HcBgGDj9VN /4QFZCOftuHqdU3uFgL27j225r4bIsAFt1dSBzTyi08LjsDzas/byE1wbN1j+qk/reYm notFF2U2pairKLHR4xcS/GOOvf5ZRL5zq8oTEYoeXLobavX7T7GvXuk79j2KjtecFyVK OhnnTSq5hYySGzqeWDgy78MFf4lbW63A37vRGZWAKb+MzYToslbH527fdxj4M/YLnlNI QUJA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1680151268; 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=u/B9dFAeaUqrqqXcKIk+Y/eQ9yVG9iQNTR7il5e9jLs=; b=ITvSaEUzvQD8Kt+lA8J1CruVuHlwy3d8+9NLWQGviMt91kGCYuyJJZuDiYaq8jqc8O lEaGEKKv8T6aMXqmOg1AyOEWp5VYYfyuotEyJrGdnAwFs6vLWgXWxcc1aogEZP0iR/j6 SKE8oiR8PbXMqBa/2RF5CnMI6jpvHXxEQi2VR9Ado/Gtj+C6y4yFtOMirOaclD6d5sSZ dNC0LyW7pIRzWVWQWXA9Bo/eLE/icN2oqbJRWSXwM6V4ni7lH0HluNfnrx5vC5tOIuh/ dB45BDyXDoCahXFKwYvHryZf8fqkoDrxHRew0dt7Dg0dZHZpGSKFjr8a7E6D8696wgk5 Br9Q== X-Gm-Message-State: AO0yUKWxTYVW7LUCqfo8xKwas6Q0qu2UM+i0vP4gRkfMZkOSC3vZxpG+ IPiu6KB675tq7iP8dPymiYTWEd44G+NswA== X-Google-Smtp-Source: AK7set99jG8l4uyr3wxeKERjnAXMdcfXxE87b+Wva1bGOUnjb4oAkZzPLPlnQdrwX8lnBEcIj6h4Fw== X-Received: by 2002:a9d:6854:0:b0:693:d998:f50c with SMTP id c20-20020a9d6854000000b00693d998f50cmr10533454oto.5.1680151267883; Wed, 29 Mar 2023 21:41:07 -0700 (PDT) Received: from wedsonaf-dev.home.lan ([189.124.190.154]) by smtp.googlemail.com with ESMTPSA id ea43-20020a056870072b00b0017e0c13b29asm7518599oab.36.2023.03.29.21.41.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 29 Mar 2023 21:41:07 -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 06/13] rust: lock: add support for `Lock::lock_irqsave` Date: Thu, 30 Mar 2023 01:39:47 -0300 Message-Id: <20230330043954.562237-6-wedsonaf@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230330043954.562237-1-wedsonaf@gmail.com> References: <20230330043954.562237-1-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 --- 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