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[2620:137:e000::1:20]) by mx.google.com with ESMTP id l7-20020a17090270c700b0019d038765f6si19368520plt.449.2023.05.17.03.34.00; Wed, 17 May 2023 03:34:15 -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=@google.com header.s=20221208 header.b=3SFYtDlz; 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=REJECT sp=REJECT dis=NONE) header.from=google.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229904AbjEQJ7b (ORCPT + 99 others); Wed, 17 May 2023 05:59:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34788 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230240AbjEQJ7Z (ORCPT ); Wed, 17 May 2023 05:59:25 -0400 Received: from mail-yw1-x114a.google.com (mail-yw1-x114a.google.com [IPv6:2607:f8b0:4864:20::114a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7D40E5BAA for ; Wed, 17 May 2023 02:59:18 -0700 (PDT) Received: by mail-yw1-x114a.google.com with SMTP id 00721157ae682-560ee0df572so7567627b3.0 for ; Wed, 17 May 2023 02:59:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1684317557; x=1686909557; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=J+riL/nvu1twHwHqCACNcwNJex8EunROGCv0pZTyq3c=; b=3SFYtDlzFGF0m5RFD90h5jV9WZN4ZQwsCYqL/L/KzsZpuhNTLNtc4NH8KkUmRUjhHw yU+/GY4lHVLt8d1eTEBvKc6iGCGTvz6I045YZE8Ng2XHGgSWo+1d0F2TwuhQuaeomJDH i/6cV5XiGTYvBIxkfd7/+PUO2skxtNeaGRppfUZYo2OsYGRYf/AbtvCjVoszYi4K7rMv NyCLauJl4qVfLHNz0jiJglxu5L01hZP5yijMYDdXMXBUcLgeVuKltS5XBDCm6fa/qfAn Dbzm2INF6PUBvWIX8Q1PMEbamATl0vdm0foAco2RbUnHFx4WCbE6oar+BGe9b+EwsDiJ KJ+Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1684317557; x=1686909557; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=J+riL/nvu1twHwHqCACNcwNJex8EunROGCv0pZTyq3c=; b=mB9MkQ+G7YUmsF3/VIkxnKkhs7LcvS5gNeeRJYMD/mm4mPvqwINgn5OEXPAYCoGjoz Obbzfid4jphTGABKEZ2rJs62TUkrWGf/Ud3beM+bGulivkYvwRr+fwQq4udC/muh8rdI afEYnV8XvfSW4Wb1+HxYCoCD5WjJZ6vxQYJSDl09KI3go99wrWMiyTCSDBs2TwiCmBHH k5AxbPmlszEPdCwLVupLfkvtIpFgFhctCaSmHRuOGipwb5tzO4tbOPME2sOZuK/ctIgJ 8ujZH4wpw0mzmAQoFvSf4/LmfpzZ0Vuo6pRL/E4Lm7FOBD0gfKXbUcgDIIG07EnFWwTB xT5Q== X-Gm-Message-State: AC+VfDwAFgVcKYI/GzgvFcepTYpgcVRQWZQzLhoeH3klOUvqIs58lUp1 EcFp0SqGXgWh1CbpOuUU/CEp2ILowvoWZ5k= X-Received: from aliceryhl.c.googlers.com ([fda3:e722:ac3:cc00:31:98fb:c0a8:6c8]) (user=aliceryhl job=sendgmr) by 2002:a81:400c:0:b0:560:c30c:75f7 with SMTP id l12-20020a81400c000000b00560c30c75f7mr15720009ywn.2.1684317557527; Wed, 17 May 2023 02:59:17 -0700 (PDT) Date: Wed, 17 May 2023 09:59:05 +0000 In-Reply-To: <20230517095905.3548100-1-aliceryhl@google.com> Mime-Version: 1.0 References: <20230517095905.3548100-1-aliceryhl@google.com> X-Mailer: git-send-email 2.40.1.606.ga4b1b128d6-goog Message-ID: <20230517095905.3548100-2-aliceryhl@google.com> Subject: [PATCH v1 2/2] rust: task: add `Send` marker to `Task` From: Alice Ryhl To: Miguel Ojeda , Wedson Almeida Filho , Alex Gaynor Cc: Boqun Feng , Gary Guo , " =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= " , Benno Lossin , Alice Ryhl , Ingo Molnar , Peter Zijlstra , Will Deacon , Mark Rutland , rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, patches@lists.linux.dev X-Spam-Status: No, score=-9.6 required=5.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE,URIBL_BLOCKED, USER_IN_DEF_DKIM_WL autolearn=ham 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: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1766137166986003322?= X-GMAIL-MSGID: =?utf-8?q?1766137166986003322?= When a type also implements `Sync`, the meaning of `Send` is just "this type may be accessed mutably from threads other than the one it is created on". That's ok for this type. Signed-off-by: Alice Ryhl --- rust/kernel/task.rs | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/rust/kernel/task.rs b/rust/kernel/task.rs index 526d29a0ae27..4f1fe9aa9f6e 100644 --- a/rust/kernel/task.rs +++ b/rust/kernel/task.rs @@ -64,6 +64,11 @@ macro_rules! current { #[repr(transparent)] pub struct Task(pub(crate) Opaque); +// SAFETY: The only situation in which this can be accessed mutably is when the refcount drops to +// zero and the destructor runs. It is safe for that to happen on any thread, so it is ok for this +// type to be `Send`. +unsafe impl Send for Task {} + // SAFETY: It's OK to access `Task` through references from other threads because we're either // accessing properties that don't change (e.g., `pid`, `group_leader`) or that are properly // synchronised by C code (e.g., `signal_pending`).