From patchwork Sat Jul 29 09:10:19 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Benno Lossin X-Patchwork-Id: 128099 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:918b:0:b0:3e4:2afc:c1 with SMTP id s11csp959981vqg; Sat, 29 Jul 2023 03:47:03 -0700 (PDT) X-Google-Smtp-Source: APBJJlF727FPbjG6d0uiEHumAG+P3VwFsNYip2qT7n3MTOQAzspOpo7mnN6PPnQJzxXk0/MlXoIb X-Received: by 2002:a17:902:f7cb:b0:1b8:9b5e:6697 with SMTP id h11-20020a170902f7cb00b001b89b5e6697mr3615971plw.68.1690627622927; Sat, 29 Jul 2023 03:47:02 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1690627622; cv=none; d=google.com; s=arc-20160816; b=IWR/xXB5hsU4GfALjCylcV80QnG4EStSAf8gMbMtQyVrON1JsCAdg6MqM0om220Fh6 c4PJ2/VCYBabfzfcf20pedakGXT/VsRNSh8QWJpcC7hzyXpDmBtPHvRSzdJ+HVuxOegf xDQEsnk2ToPzX6k4TydGEDfuFZpLKgL6DM4/FLyWmFyiM4PA7OX5t7RDNDJjYi4Eeihi lHobhZN09QwQCAz0hgnE77RK9pKe+M+vutFqiImgSAoldzv4kYJEIfIiHcMDopa/2xUq itbuK6ODb9aOFFE5Q8BbUMZtAqU4AHC9ceCcIE/udTjoPWqAoyVgtdFUolh8Wan3sb/Y T6Hw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :feedback-id:references:in-reply-to:message-id:subject:cc:from:to :dkim-signature:date; bh=3zNIMZmZNDCpyXxxyP7KXlpj+oRhkgVcL+Ru9AKEqMQ=; fh=qm1bOEYzVYZKL4fg86TgWb8D+QJA9mGpUhKFp2A6Xio=; b=HpEfwwsTQn0m667XS/4kY+RUCppi0IJZ9yS9PHInccJXnkWmMmYXyYtBXpnNvPQlrb rp1HeVzImCi61ofPhgHP9DwmxSxcmnj9Kv0g4OUH2VYaqWNrgSJHJLdCv/KLmzwDeJl+ QG+daxhWZru61jeVMu54yhrDk+ojG2sBEcKzGVnK0pD4MFpl7M2Zy6WqpUBlZOL7RiPn gMiw1veSx/9Bb9xRHTyOc8cYAr+6hffpVL9NZGqdPBWJG2iTw6KagYFW+xAM6Y+rKwfT OaILHBLxwQvDmEUwJJoDahAv8DAbt37CVygHPZTSPLFpCwVwyJ7UJN1DsU78byjyqyXI t4Zg== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@proton.me header.s=protonmail header.b=chbVs6fH; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=QUARANTINE sp=QUARANTINE dis=NONE) header.from=proton.me Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id p4-20020a170902e74400b001b3d27ca12fsi4621920plf.207.2023.07.29.03.46.47; Sat, 29 Jul 2023 03:47:02 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@proton.me header.s=protonmail header.b=chbVs6fH; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=QUARANTINE sp=QUARANTINE dis=NONE) header.from=proton.me Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231206AbjG2JLo (ORCPT + 99 others); Sat, 29 Jul 2023 05:11:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40728 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231693AbjG2JLU (ORCPT ); Sat, 29 Jul 2023 05:11:20 -0400 Received: from mail-4316.protonmail.ch (mail-4316.protonmail.ch [185.70.43.16]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D689B44BC for ; Sat, 29 Jul 2023 02:10:37 -0700 (PDT) Date: Sat, 29 Jul 2023 09:10:19 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=proton.me; s=protonmail; t=1690621832; x=1690881032; bh=3zNIMZmZNDCpyXxxyP7KXlpj+oRhkgVcL+Ru9AKEqMQ=; h=Date:To:From:Cc:Subject:Message-ID:In-Reply-To:References: Feedback-ID:From:To:Cc:Date:Subject:Reply-To:Feedback-ID: Message-ID:BIMI-Selector; b=chbVs6fHFDVnXKLqa/IdGHFF5wg9kxo0llJBCweB/b7pRciP4kY9xe5QSS3DJ97WN uuwVujcl8aAnoN7sMarSEODG0XBsxPWGk9vkwzEf1TDMbgU3t0UkktB6ubMvudcaR3 BF98jn3lt4nCyIhWqxzhgqIWflFdHbSk1MQNDtq43mkoW3FgD+CFxTTmkmL/3nJqwZ 2dIBXYQJrjoe4V9Pv99c2YkGP75+1+LdHEUcsqT4XLwp18HuOtsubnoibAjy5VKiLb pZHaZwjcpy1ndewgQ6f1t361S+Hu83O7O2ERAQxw0mnZsFJnRg+CvcW2VwMXcrVKNE zzLMZTVZagUSQ== To: Miguel Ojeda , Wedson Almeida Filho , Alex Gaynor From: Benno Lossin Cc: Boqun Feng , Gary Guo , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , Benno Lossin , Alice Ryhl , Andreas Hindborg , rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v3 10/13] rust: init: implement `Zeroable` for `UnsafeCell` and `Opaque` Message-ID: <20230729090838.225225-11-benno.lossin@proton.me> In-Reply-To: <20230729090838.225225-1-benno.lossin@proton.me> References: <20230729090838.225225-1-benno.lossin@proton.me> Feedback-ID: 71780778:user:proton MIME-Version: 1.0 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_MSPIKE_H5, RCVD_IN_MSPIKE_WL,SPF_HELO_PASS,SPF_PASS,T_SCC_BODY_TEXT_LINE, URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1772751549896776767 X-GMAIL-MSGID: 1772751549896776767 `UnsafeCell` and `T` have the same layout so if `T` is `Zeroable` then so should `UnsafeCell` be. This allows using the derive macro for `Zeroable` on types that contain an `UnsafeCell`. Since `Opaque` contains a `MaybeUninit`, all bytes zero is a valid bit pattern for that type. Signed-off-by: Benno Lossin Reviewed-by: Martin Rodriguez Reboredo Reviewed-by: Gary Guo --- v2 -> v3: - also implement Zeroable for `UnsafeCell` when `T: Zeroable`, - use `impl_zeroable!` instead of `derive(Zeroable)`. rust/kernel/init.rs | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/rust/kernel/init.rs b/rust/kernel/init.rs index af96d4acc26b..06ecab4901f2 100644 --- a/rust/kernel/init.rs +++ b/rust/kernel/init.rs @@ -212,10 +212,12 @@ use crate::{ error::{self, Error}, sync::UniqueArc, + types::Opaque, }; use alloc::boxed::Box; use core::{ alloc::AllocError, + cell::UnsafeCell, convert::Infallible, marker::PhantomData, mem::MaybeUninit, @@ -1157,6 +1159,11 @@ macro_rules! impl_zeroable { // SAFETY: Type is allowed to take any value, including all zeros. {} MaybeUninit, + // SAFETY: Type is allowed to take any value, including all zeros. + {} Opaque, + + // SAFETY: `T: Zeroable` and `UnsafeCell` is `repr(transparent)`. + {} UnsafeCell, // SAFETY: All zeros is equivalent to `None` (option layout optimization guarantee). Option, Option, Option, Option,