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[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