From patchwork Fri Mar 31 21:53:25 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: y86-dev X-Patchwork-Id: 78003 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:b0ea:0:b0:3b6:4342:cba0 with SMTP id b10csp870471vqo; Fri, 31 Mar 2023 15:11:42 -0700 (PDT) X-Google-Smtp-Source: AKy350amSIrFoBr7IH5c6zVXdom15CIWRsTsHlEszusmztqt2xq2LzjN3j9NHcQCwkO3SKim3j3m X-Received: by 2002:a17:906:55cd:b0:933:1134:be1e with SMTP id z13-20020a17090655cd00b009331134be1emr26160424ejp.53.1680300702150; Fri, 31 Mar 2023 15:11:42 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1680300702; cv=none; d=google.com; s=arc-20160816; b=pcjxpW6sNUABJ7kAEZFhXptapmootLWZ7RBmXvO4qyEzdd/11DToSngMhY8nFV11L4 bnybgHyjJRsKuSZ41tTDVxCeuLYftgEZFHBp63cjRZGtmcuzCK/Obv/tK0sKg5dp6y07 F//kI0moIPoUJyEA8P/BJXM2YDleNKFuSyKIkj91xb31qAgh+Mq2PbuhFWFkLBdZ7Ahi r9TNH/W0cS9VarOpKZRLs7khX3Y4Vnsxaiu+0lB6pXmUHtzMxOPAXCvrSJonOXVSDK2B tNARsvDPi3QM6SBzfwCcCJLoVh2SlIsSSpf6n7fcWTBKl9OLfLRpqbFQrkVPp1kcQ7Wz tPyg== 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:message-id:subject:cc:from:to:dkim-signature:date; bh=DPTzK+Qui1IJXTgvMYy9gbdRtBobG73CivdLCgcwUrA=; b=lYyRTdK7OoFzrgRrL3KN03mVq6KUEnrHntfP7kvrzQH1CSM9vA9NmLwtpkp61ohQRx V/gpCnZj2crt/Xszs/7nsojIDCSkA5grK3li5V6NPXifC2RJjOIWWdJOIaTJZLuTWig7 z8xTSKaNmWk8pzVpvuQGzPZ24XLdVFpnWT+nnUxEjShYhST9Izxs5zFv60/mtbB7qQMh RWZsSE5eowbTm0hFxY/8696vNa6Pd5mZ1AdWzMAKID3fvVIKlPGv3RV5Zny+lyp1984R crufFrelj4nq+Tq9gB24EydjrVZymH5H8IheG0N6CwfgOQioe05/ulPn6pBYe0CjCTkv 8eDQ== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@protonmail.com header.s=protonmail3 header.b=GJKpOeXl; 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=protonmail.com Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id x9-20020a170906134900b008cc8a6fea26si2875219ejb.561.2023.03.31.15.11.18; Fri, 31 Mar 2023 15:11:42 -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=@protonmail.com header.s=protonmail3 header.b=GJKpOeXl; 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=protonmail.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233376AbjCaVzC (ORCPT + 99 others); Fri, 31 Mar 2023 17:55:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46806 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233297AbjCaVyl (ORCPT ); Fri, 31 Mar 2023 17:54:41 -0400 Received: from mail-40133.protonmail.ch (mail-40133.protonmail.ch [185.70.40.133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D281221ABA; Fri, 31 Mar 2023 14:54:01 -0700 (PDT) Date: Fri, 31 Mar 2023 21:53:25 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=protonmail.com; s=protonmail3; t=1680299614; x=1680558814; bh=DPTzK+Qui1IJXTgvMYy9gbdRtBobG73CivdLCgcwUrA=; h=Date:To:From:Cc:Subject:Message-ID:Feedback-ID:From:To:Cc:Date: Subject:Reply-To:Feedback-ID:Message-ID:BIMI-Selector; b=GJKpOeXlyfaIGROdt2A8y+Ftn/Jd2JxDZTszCitNIuOOeDCJb0m8PjU1KZ8Qe6nMg N574iFyvm1sGmspnBarR5Da/i93FbOzPe/mBjs/BkNWW3w1FtygzX2xOePNjMDiEL2 3e9MynpzyOPJpBzR/qfbMg+tmeC/xSImhXv34r580U9eu7FjAeQitSN/izDpu5FAp8 OuJvpogDGDVLjlbxYzwvjjv0MKZGn+ZaZqD/sJDrMUceazE6id61jLDU0eQUiykCt8 edbHUtSZ7rKWBbLXakNTqTbg8ss2GJhF3Er6zwmGIltxGNO0o56blGbLMNLB6U/htB P9kfOVaHuVNGw== To: Miguel Ojeda , Alex Gaynor , Wedson Almeida Filho , Boqun Feng , Gary Guo , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , Alice Ryhl From: y86-dev@protonmail.com Cc: rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, patches@lists.linux.dev, Benno Lossin , Andreas Hindborg , Alice Ryhl Subject: [PATCH v4 08/15] rust: init/sync: add `InPlaceInit` trait to pin-initialize smart pointers Message-ID: <20230331215053.585759-9-y86-dev@protonmail.com> Feedback-ID: 40624463:user:proton MIME-Version: 1.0 X-Spam-Status: No, score=-0.2 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_FROM,RCVD_IN_MSPIKE_H2, SPF_HELO_PASS,SPF_PASS 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: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1761922988788827173?= X-GMAIL-MSGID: =?utf-8?q?1761922988788827173?= From: Benno Lossin The `InPlaceInit` trait that provides two functions, for initializing using `PinInit` and `Init`. It is implemented by `Arc`, `UniqueArc` and `Box`. Signed-off-by: Benno Lossin Cc: Andreas Hindborg Cc: Alice Ryhl Cc: Gary Guo --- rust/kernel/init.rs | 128 ++++++++++++++++++++++++++++++++++++---- rust/kernel/sync/arc.rs | 23 ++++++++ 2 files changed, 138 insertions(+), 13 deletions(-) -- 2.39.2 diff --git a/rust/kernel/init.rs b/rust/kernel/init.rs index 14cc5d2dafef..cf2b9ee6ce0e 100644 --- a/rust/kernel/init.rs +++ b/rust/kernel/init.rs @@ -114,10 +114,16 @@ //! [`impl Init`]: Init //! [`Opaque`]: kernel::types::Opaque //! [`pin_data`]: ::macros::pin_data -//! [`UniqueArc`]: kernel::sync::UniqueArc +use crate::{ + error::{self, Error}, + sync::UniqueArc, +}; use alloc::boxed::Box; -use core::{cell::Cell, convert::Infallible, marker::PhantomData, mem::MaybeUninit, ptr}; +use core::{ + alloc::AllocError, cell::Cell, convert::Infallible, marker::PhantomData, mem::MaybeUninit, + pin::Pin, ptr, +}; #[doc(hidden)] pub mod __internal; @@ -309,7 +315,6 @@ pub mod macros; /// /// [`try_pin_init!`]: kernel::try_pin_init /// [`NonNull`]: core::ptr::NonNull -/// [`Error`]: kernel::error::Error // For a detailed example of how this macro works, see the module documentation of the hidden // module `__internal` inside of `init/__internal.rs`. #[macro_export] @@ -363,8 +368,6 @@ macro_rules! pin_init { /// } /// } /// ``` -/// -/// [`Error`]: kernel::error::Error // For a detailed example of how this macro works, see the module documentation of the hidden // module `__internal` inside of `init/__internal.rs`. #[macro_export] @@ -586,8 +589,6 @@ macro_rules! try_pin_init { /// /// This initializer is for initializing data in-place that might later be moved. If you want to /// pin-initialize, use [`pin_init!`]. -/// -/// [`Error`]: kernel::error::Error // For a detailed example of how this macro works, see the module documentation of the hidden // module `__internal` inside of `init/__internal.rs`. #[macro_export] @@ -638,8 +639,6 @@ macro_rules! init { /// } /// } /// ``` -/// -/// [`Error`]: kernel::error::Error // For a detailed example of how this macro works, see the module documentation of the hidden // module `__internal` inside of `init/__internal.rs`. #[macro_export] @@ -845,7 +844,8 @@ macro_rules! try_init { /// A pin-initializer for the type `T`. /// /// To use this initializer, you will need a suitable memory location that can hold a `T`. This can -/// be [`Box`], [`Arc`], [`UniqueArc`]. +/// be [`Box`], [`Arc`], [`UniqueArc`]. Use the [`InPlaceInit::pin_init`] function of a +/// smart pointer like [`Arc`] on this. /// /// Also see the [module description](self). /// @@ -864,7 +864,6 @@ macro_rules! try_init { /// /// [`Arc`]: crate::sync::Arc /// [`Arc::pin_init`]: crate::sync::Arc::pin_init -/// [`UniqueArc`]: kernel::sync::UniqueArc #[must_use = "An initializer must be used in order to create its value."] pub unsafe trait PinInit: Sized { /// Initializes `slot`. @@ -881,7 +880,8 @@ pub unsafe trait PinInit: Sized { /// An initializer for `T`. /// /// To use this initializer, you will need a suitable memory location that can hold a `T`. This can -/// be [`Box`], [`Arc`], [`UniqueArc`]. Because [`PinInit`] is a super trait, you can +/// be [`Box`], [`Arc`], [`UniqueArc`]. Use the [`InPlaceInit::init`] function of a smart +/// pointer like [`Arc`] on this. Because [`PinInit`] is a super trait, you can /// use every function that takes it as well. /// /// Also see the [module description](self). @@ -906,7 +906,6 @@ pub unsafe trait PinInit: Sized { /// move the pointee after initialization. /// /// [`Arc`]: crate::sync::Arc -/// [`UniqueArc`]: kernel::sync::UniqueArc #[must_use = "An initializer must be used in order to create its value."] pub unsafe trait Init: PinInit { /// Initializes `slot`. @@ -981,3 +980,106 @@ unsafe impl Init for T { Ok(()) } } + +/// Smart pointer that can initialize memory in-place. +pub trait InPlaceInit: Sized { + /// Use the given pin-initializer to pin-initialize a `T` inside of a new smart pointer of this + /// type. + /// + /// If `T: !Unpin` it will not be able to move afterwards. + fn try_pin_init(init: impl PinInit) -> Result, E> + where + E: From; + + /// Use the given pin-initializer to pin-initialize a `T` inside of a new smart pointer of this + /// type. + /// + /// If `T: !Unpin` it will not be able to move afterwards. + fn pin_init(init: impl PinInit) -> error::Result> + where + Error: From, + { + // SAFETY: We delegate to `init` and only change the error type. + let init = unsafe { + pin_init_from_closure(|slot| init.__pinned_init(slot).map_err(|e| Error::from(e))) + }; + Self::try_pin_init(init) + } + + /// Use the given initializer to in-place initialize a `T`. + fn try_init(init: impl Init) -> Result + where + E: From; + + /// Use the given initializer to in-place initialize a `T`. + fn init(init: impl Init) -> error::Result + where + Error: From, + { + // SAFETY: We delegate to `init` and only change the error type. + let init = unsafe { + init_from_closure(|slot| init.__pinned_init(slot).map_err(|e| Error::from(e))) + }; + Self::try_init(init) + } +} + +impl InPlaceInit for Box { + #[inline] + fn try_pin_init(init: impl PinInit) -> Result, E> + where + E: From, + { + let mut this = Box::try_new_uninit()?; + let slot = this.as_mut_ptr(); + // SAFETY: When init errors/panics, slot will get deallocated but not dropped, + // slot is valid and will not be moved, because we pin it later. + unsafe { init.__pinned_init(slot)? }; + // SAFETY: All fields have been initialized. + Ok(unsafe { this.assume_init() }.into()) + } + + #[inline] + fn try_init(init: impl Init) -> Result + where + E: From, + { + let mut this = Box::try_new_uninit()?; + let slot = this.as_mut_ptr(); + // SAFETY: When init errors/panics, slot will get deallocated but not dropped, + // slot is valid. + unsafe { init.__init(slot)? }; + // SAFETY: All fields have been initialized. + Ok(unsafe { this.assume_init() }) + } +} + +impl InPlaceInit for UniqueArc { + #[inline] + fn try_pin_init(init: impl PinInit) -> Result, E> + where + E: From, + { + let mut this = UniqueArc::try_new_uninit()?; + let slot = this.as_mut_ptr(); + // SAFETY: When init errors/panics, slot will get deallocated but not dropped, + // slot is valid and will not be moved, because we pin it later. + unsafe { init.__pinned_init(slot)? }; + // SAFETY: All fields have been initialized. + Ok(unsafe { this.assume_init() }.into()) + } + + #[inline] + fn try_init(init: impl Init) -> Result + where + E: From, + { + let mut this = UniqueArc::try_new_uninit()?; + let slot = this.as_mut_ptr(); + // SAFETY: When init errors/panics, slot will get deallocated but not dropped, + // slot is valid. + unsafe { init.__init(slot)? }; + // SAFETY: All fields have been initialized. + Ok(unsafe { this.assume_init() }) + } +} diff --git a/rust/kernel/sync/arc.rs b/rust/kernel/sync/arc.rs index eee7008e5e3e..24dc96603090 100644 --- a/rust/kernel/sync/arc.rs +++ b/rust/kernel/sync/arc.rs @@ -17,6 +17,7 @@ use crate::{ bindings, + init::{InPlaceInit, Init, PinInit}, types::{ForeignOwnable, Opaque}, }; use alloc::boxed::Box; @@ -163,6 +164,28 @@ impl Arc { // `Arc` object. Ok(unsafe { Self::from_inner(Box::leak(inner).into()) }) } + + /// Use the given initializer to in-place initialize a `T`. + /// + /// If `T: !Unpin` it will not be able to move afterwards. + #[inline] + pub fn pin_init(init: impl PinInit) -> Result + where + Error: From, + { + UniqueArc::pin_init(init).map(|u| u.into()) + } + + /// Use the given initializer to in-place initialize a `T`. + /// + /// This is equivalent to [`pin_init`], since an [`Arc`] is always pinned. + #[inline] + pub fn init(init: impl Init) -> Result + where + Error: From, + { + UniqueArc::init(init).map(|u| u.into()) + } } impl Arc {