From patchwork Fri Feb 24 07:59:33 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Asahi Lina X-Patchwork-Id: 61185 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a5d:5915:0:0:0:0:0 with SMTP id v21csp776825wrd; Fri, 24 Feb 2023 00:29:44 -0800 (PST) X-Google-Smtp-Source: AK7set/iT3bkXUxL1ngtJnbT9nQivtNnY/n8AUrzKnk+a00QzJUGJ5ByTl/sDRcEMHfWe7oOM5Hk X-Received: by 2002:aa7:9608:0:b0:5dc:ecea:fc8b with SMTP id q8-20020aa79608000000b005dceceafc8bmr4143605pfg.29.1677227383835; Fri, 24 Feb 2023 00:29:43 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1677227383; cv=none; d=google.com; s=arc-20160816; b=SyYAnEBgEXfZLXwYqlBErinFzzaq12hxvmtSl4Qy7k75kjM9OL52gqGeSRJ4r18k/5 FBUrujwnRt/BWr0j/i7lRhI/aDgMRazmwtSpTvQfgPCBiv0VmFN6j2YscV+cbJxBoRc+ 2xb1g5e+p4h3wlPClwkMtaDRV8ZJzXXLQ9tWYtIzsPvGAhNECidlIWHbmF3ryPoJHieO 47myfSkzzhfkT99YM7R/CAI+u3W6Fy9gugP2pbN/eHUv9vIGTdC6vpjqL5Te3g08NadW b39goK+Sp+e3/IVQVKsQtv9AnEbZQG4yNO0Bl83qx3RifVO4EGHpQfjuQ1i4mKHUh+7Q SZCw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:cc:to:in-reply-to:references:message-id :content-transfer-encoding:mime-version:subject:date:from :dkim-signature; bh=E4Sj1q7Pj9vOfP3949fgGlvuLEXC4g2Av96JtB1Avmw=; b=dOyzR9PuxFqd/YG32KshCW5bEFa9U7zlErL2otIsXD3DlLylH6vrztJt9KPSByibHg dB7RGnwQ0rtPwTeiRlN0j9nZErCb+BRH8pRwLGxyGQ2iTWwmq5DB22YLncZx18489Eyy vAjgwds7dZhwiEFWIULxo8K5o5SysaDSKMoQg0OMt4hNODfEpNhTQulUaztp7ukyvkxl N2o8uA5bu6kZpmelZaC/ByYqR7bEFW/ltaUOYb0ZDv3kT4eILrHVYXAU9JPBFpGsg/dy 6YNJFmnJMHom/TLn8+HkqUb3FRsPgag4YqDUAiz8/JjVFEgnvgPJwoyLM6nqUMHF2VXQ wo9g== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@asahilina.net header.s=default header.b=HNf14lwW; 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=asahilina.net Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id m3-20020a632603000000b004fb358f497esi1163029pgm.436.2023.02.24.00.29.31; Fri, 24 Feb 2023 00:29:43 -0800 (PST) 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=@asahilina.net header.s=default header.b=HNf14lwW; 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=asahilina.net Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229625AbjBXIAO (ORCPT + 99 others); Fri, 24 Feb 2023 03:00:14 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49314 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229587AbjBXIAI (ORCPT ); Fri, 24 Feb 2023 03:00:08 -0500 Received: from mail.marcansoft.com (marcansoft.com [212.63.210.85]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D1E4221950; Fri, 24 Feb 2023 00:00:06 -0800 (PST) Received: from [127.0.0.1] (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: linasend@asahilina.net) by mail.marcansoft.com (Postfix) with ESMTPSA id CB14A425FF; Fri, 24 Feb 2023 08:00:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=asahilina.net; s=default; t=1677225605; bh=6Wbnei3k6KtVJz9ZI7M1PVB1moPrUHEpETOWDNtBwL8=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=HNf14lwW2ZiKP2wSRb6ZYYx6kIurcsxTrTnaYTiE6pGBGgNBb46Ayp/vt5XW7NxNN h44pAvXfwVovff8VmmBWdLlUp6gHjUt1LpSQmKUl6P3JRrW7JwLLsbp1bXXBLjQ+Ar qSqSZWTSYgMAGbCWtDztaRsnOrDmjGn0LKUjH9+bs9h8EXFJYyJP7Q/D/1R+Bqi8tY klxNRUOyZMwJJyqUYsWvDJIMpwmO5sdgqY2RmpMzhO587mAC2a1pCNgk16LPtOO24+ 3XWeauLuT2R37YdJmBrZUSUbZMi8bEt7hhx19NXNbpyNc4h+zy4HeEq4rhFjf4wM8K cmoc/rD1KdouA== From: Asahi Lina Date: Fri, 24 Feb 2023 16:59:33 +0900 Subject: [PATCH 1/2] rust: sync: arc: implement Arc::downcast() MIME-Version: 1.0 Message-Id: <20230224-rust-arc-v1-1-568eea613a41@asahilina.net> References: <20230224-rust-arc-v1-0-568eea613a41@asahilina.net> In-Reply-To: <20230224-rust-arc-v1-0-568eea613a41@asahilina.net> To: Miguel Ojeda , Alex Gaynor , Wedson Almeida Filho , Boqun Feng , Gary Guo , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= Cc: rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, asahi@lists.linux.dev, Asahi Lina X-Mailer: b4 0.12.0 X-Developer-Signature: v=1; a=ed25519-sha256; t=1677225599; l=1738; i=lina@asahilina.net; s=20230221; h=from:subject:message-id; bh=6Wbnei3k6KtVJz9ZI7M1PVB1moPrUHEpETOWDNtBwL8=; b=pl+lv4Tc3xCIBS5/RLRLXHflMYEspfZVvyeG9O2EVpNFAe5b/JOSXqDeabDbmi3eE4wYUsw3B FzcsitZwuTzClhPwm86Jxdx/DHXFqY5N7mORtzgFbDCpcbFGBp+cqZy X-Developer-Key: i=lina@asahilina.net; a=ed25519; pk=Qn8jZuOtR1m5GaiDfTrAoQ4NE1XoYVZ/wmt5YtXWFC4= X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,SPF_HELO_NONE,SPF_PASS 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?1758700381681493948?= X-GMAIL-MSGID: =?utf-8?q?1758700381681493948?= This mirrors the standard library's alloc::sync::Arc::downcast(). Based on the Rust standard library implementation, ver 1.62.0, licensed under "Apache-2.0 OR MIT", from: https://github.com/rust-lang/rust/tree/1.62.0/library/alloc/src For copyright details, please see: https://github.com/rust-lang/rust/blob/1.62.0/COPYRIGHT Signed-off-by: Asahi Lina Reviewed-by: Martin Rodriguez Reboredo Reviewed-by: Gary Guo Reviewed-by: Andreas Hindborg Reviewed-by: Vincenzo Palazzo --- rust/kernel/sync/arc.rs | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/rust/kernel/sync/arc.rs b/rust/kernel/sync/arc.rs index a94e303217c6..752bd7c4699e 100644 --- a/rust/kernel/sync/arc.rs +++ b/rust/kernel/sync/arc.rs @@ -22,6 +22,7 @@ use crate::{ }; use alloc::boxed::Box; use core::{ + any::Any, fmt, marker::{PhantomData, Unsize}, mem::{ManuallyDrop, MaybeUninit}, @@ -220,6 +221,27 @@ impl ForeignOwnable for Arc { } } +impl Arc { + /// Attempt to downcast the `Arc` to a concrete type. + // Based on the Rust standard library implementation, ver 1.62.0, which is + // Apache-2.0 OR MIT. + pub fn downcast(self) -> core::result::Result, Self> + where + T: Any + Send + Sync, + { + if (*self).is::() { + // SAFETY: We have just checked that the type is correct, so we can cast the pointer. + unsafe { + let ptr = self.ptr.cast::>(); + core::mem::forget(self); + Ok(Arc::from_inner(ptr)) + } + } else { + Err(self) + } + } +} + impl Deref for Arc { type Target = T; From patchwork Fri Feb 24 07:59:34 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Asahi Lina X-Patchwork-Id: 61184 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a5d:5915:0:0:0:0:0 with SMTP id v21csp776821wrd; Fri, 24 Feb 2023 00:29:43 -0800 (PST) X-Google-Smtp-Source: AK7set/Uirk3iEy00KPc1bJTYQZHpHvXFNLiPQNHKI4tFtLuEt9UPrCdQdyO2OW6qNgAhphDpkEF X-Received: by 2002:a17:902:cec9:b0:19c:d457:ff22 with SMTP id d9-20020a170902cec900b0019cd457ff22mr1839886plg.48.1677227382890; Fri, 24 Feb 2023 00:29:42 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1677227382; cv=none; d=google.com; s=arc-20160816; b=lcke7qvqB61EeLse33FrMWNGEnMLjQSTDw8ciyN1SGhhkKLJYIxQpwdnnCnLFyGokb 9FVR1vvQnLqx3kBXH5BxchTSFNqONHJ1BpK+yAJi+Y5dh8SYpq2ogXVdy3TE8qB7XrV/ U7Et8ParDHIJp7hvh3kEgECsS3HTh98UOYsj8X9T9+4d7VkWxXRMYLOTOOMsQMWDa57i rHIZxEyDD9g8fLJxmDcw0z1OM9oTOwIcCbM/YuhgzZSbClxrhL/VemZVZABrtOUx/A4S 25tCi6MuNtWIdAJYAQo5mL15+vE+tZUV5RXSGAIlBvjNba/ODa6BeYoPobdmwo9L6bgH sVzg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:cc:to:in-reply-to:references:message-id :content-transfer-encoding:mime-version:subject:date:from :dkim-signature; bh=+HoLkbnHsdxO4iZR5B0SgQXHLvS0D+9DE9/JMcF1NmQ=; b=wRYZKKGr8dIEWJZhZ0IH71RazjU3okY4Rq9kLSr/VzH+18KbqL42LXcRgLRMKQPUfm jzQiW/c8wqPSb1m23BqLyYjYLxQQZPkFTvj4qqYeDb9a45rikTByB9okv6sGWiwxyI6v G9Vd0C/26gs7uLGpiSeKNih6dz0xXawQCI2sSu7nDgZ8IY5EXui6vFIV9RzvRAG0POJW ylj0FAWm+vuvgphSfM/hn4heeGCYo0XP9a6ae+GxFYnU+VjORNLA4OnnWyTjZg8FS/kL dSupQacgYA5HtuqA1rPR1WRf8ajvBHr9xc0CWKuNiurUq5y4mbcsP13hfIbDF5WpIzoE E3xQ== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@asahilina.net header.s=default header.b=tER4tx7J; 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=asahilina.net Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id kp12-20020a170903280c00b0019ca9b843b0si6477754plb.329.2023.02.24.00.29.30; Fri, 24 Feb 2023 00:29:42 -0800 (PST) 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=@asahilina.net header.s=default header.b=tER4tx7J; 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=asahilina.net Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229622AbjBXIAT (ORCPT + 99 others); Fri, 24 Feb 2023 03:00:19 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49364 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229617AbjBXIAL (ORCPT ); Fri, 24 Feb 2023 03:00:11 -0500 Received: from mail.marcansoft.com (marcansoft.com [212.63.210.85]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E993122DEF; Fri, 24 Feb 2023 00:00:09 -0800 (PST) Received: from [127.0.0.1] (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: linasend@asahilina.net) by mail.marcansoft.com (Postfix) with ESMTPSA id E970C42627; Fri, 24 Feb 2023 08:00:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=asahilina.net; s=default; t=1677225608; bh=0Up47y7KEYhekwntYgr5syUpa6Dxb/pGbZHOT4tPwJM=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=tER4tx7J4m3yFPMir0rEV1nhCYmxofpML4pw1lwQYZhVt3OM2iNb41mFu4itCF3Q4 Vk+V16EjWGKqAGT1XCMFkiH1f4BwehRYbZWCZ7/E+dhMp4hDAxaBZ+xO80N7NSFeoO 1P59zVIfTE+Epbm2JUshFd51dHWmY2yBBz+uWOU9NAGCVFEWN7KWe73/lcClmsWnFs wrEVjuinO7AJ+Hw2ompz99OxVd54JjTtD9FXuNUOYnuDXRLCF/XH1nErXRz3CsuJZ+ XyDsZjJrbLXKC814dS1xE5WE3jNkKEulgILcNARN6Ow7Nyjdc3TnkU7W2dr4FnN50K sQDP3r5UapMaA== From: Asahi Lina Date: Fri, 24 Feb 2023 16:59:34 +0900 Subject: [PATCH 2/2] rust: sync: arc: Add UniqueArc::assume_init() MIME-Version: 1.0 Message-Id: <20230224-rust-arc-v1-2-568eea613a41@asahilina.net> References: <20230224-rust-arc-v1-0-568eea613a41@asahilina.net> In-Reply-To: <20230224-rust-arc-v1-0-568eea613a41@asahilina.net> To: Miguel Ojeda , Alex Gaynor , Wedson Almeida Filho , Boqun Feng , Gary Guo , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= Cc: rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, asahi@lists.linux.dev, Asahi Lina X-Mailer: b4 0.12.0 X-Developer-Signature: v=1; a=ed25519-sha256; t=1677225599; l=1757; i=lina@asahilina.net; s=20230221; h=from:subject:message-id; bh=0Up47y7KEYhekwntYgr5syUpa6Dxb/pGbZHOT4tPwJM=; b=uJ1yTsqKiJ60A7a9DGhqliBpLPZdFYZvgKBN4QFlYL8xz5Fq/DvvPu1HeHmu9Ru9FqBj2uX1Z Y9EbTDTSc0QC01RK+qseEH2NcYWjE1RCHtAH9DyQH9p4mLLqKfKcyLh X-Developer-Key: i=lina@asahilina.net; a=ed25519; pk=Qn8jZuOtR1m5GaiDfTrAoQ4NE1XoYVZ/wmt5YtXWFC4= X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,SPF_HELO_NONE,SPF_PASS 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?1758700380599688666?= X-GMAIL-MSGID: =?utf-8?q?1758700380599688666?= We can already create `UniqueArc>` instances with `UniqueArc::try_new_uninit()` and write to them with `write()`. Add the missing unsafe `assume_init()` function to promote it to `UniqueArc`, so users can do piece-wise initialization of the contents instead of doing it all at once as long as they keep the invariants (the same requirements as `MaybeUninit::assume_init()`). This mirrors the std `Arc::assume_init()` function. In the kernel, since we have `UniqueArc`, arguably this only belongs there since most use cases will initialize it immediately after creating it, before demoting it to `Arc` to share it. Signed-off-by: Asahi Lina Reviewed-by: Martin Rodriguez Reboredo Reviewed-by: Andreas Hindborg Reviewed-by: Vincenzo Palazzo --- rust/kernel/sync/arc.rs | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/rust/kernel/sync/arc.rs b/rust/kernel/sync/arc.rs index 752bd7c4699e..b8e9477fe865 100644 --- a/rust/kernel/sync/arc.rs +++ b/rust/kernel/sync/arc.rs @@ -512,6 +512,15 @@ impl UniqueArc> { /// Converts a `UniqueArc>` into a `UniqueArc` by writing a value into it. pub fn write(mut self, value: T) -> UniqueArc { self.deref_mut().write(value); + // SAFETY: We have just written the contents fully. + unsafe { self.assume_init() } + } + + /// Returns a UniqueArc, assuming the MaybeUninit has already been initialized. + /// + /// # Safety + /// The contents of the UniqueArc must have already been fully initialized. + pub unsafe fn assume_init(self) -> UniqueArc { let inner = ManuallyDrop::new(self).inner.ptr; UniqueArc { // SAFETY: The new `Arc` is taking over `ptr` from `self.inner` (which won't be