From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id D7423EE36AC for ; Thu, 12 Feb 2026 17:23:47 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 224FE6B0088; Thu, 12 Feb 2026 12:23:47 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 1D2676B0089; Thu, 12 Feb 2026 12:23:47 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0DF8A6B008A; Thu, 12 Feb 2026 12:23:47 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id ED9D96B0088 for ; Thu, 12 Feb 2026 12:23:46 -0500 (EST) Received: from smtpin15.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id 825221A0276 for ; Thu, 12 Feb 2026 17:23:46 +0000 (UTC) X-FDA: 84436476852.15.53B04DB Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf14.hostedemail.com (Postfix) with ESMTP id C3F94100005 for ; Thu, 12 Feb 2026 17:23:44 +0000 (UTC) Authentication-Results: imf14.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=J1jfRton; spf=pass (imf14.hostedemail.com: domain of a.hindborg@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=a.hindborg@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1770917024; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=so4QGrJOcY7JuWr3cPaTVDLZ62UF9pT/A5r7PuP9lGE=; b=gwFpt+NUP1mW7paijqgkLK9X1cScHPJ6KdcVij1FZC0cqHFZV75DWkWPPWYoEiu66D5bFo hdd+aiZUeXDjBWogkGRXLRbBa5L0Z96COJJ8sixwDzuPrLOGYar+93zNzwX74pCbDmSQjX B30+t+F9IWCiUqmRfCnQJp/Owba88M8= ARC-Authentication-Results: i=1; imf14.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=J1jfRton; spf=pass (imf14.hostedemail.com: domain of a.hindborg@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=a.hindborg@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1770917024; a=rsa-sha256; cv=none; b=vNgB/ClsFL3mi/+ftctbaGjSbnVAAhi0M/rPYNgI/DUb60rv8sj0X8FPts7NY15sQ41ez9 hPrkFp1WigRwTT4Iq/IlMUVSOtCLz4KyLmndJVR7rw9cbTduwGPstTGMGz0iSXRqh0XfEo /IoPfU2W5QmY+uZm9hgYsHXZ7Z+SCJM= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id C63B3444FC; Thu, 12 Feb 2026 17:23:43 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5109EC4CEF7; Thu, 12 Feb 2026 17:23:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1770917023; bh=so4QGrJOcY7JuWr3cPaTVDLZ62UF9pT/A5r7PuP9lGE=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=J1jfRtonQwBnquYFfzu5ltBwES3ulkbPUHEzJr3NS9bM/5ujnYx2dHiY5ClUTTrwz TxmEErZT4EpfFh8es7SLaolgKnOY3+Khe6QdldXbDuRznz/nxlsdPL+gd4HdpEOabD wYU8Rr2ux0yKbiX3RJHSU67TF/TI9d2TAm2AjTaEiDoKZo2NIt7xsrxHVRJBB2nXGC q12bKAPrmLpSQZATzq43PHoTZ7lZabJxmJy6HVH2zVwM0EWFrOMV39Uxm7NcstzZmh fpWp28cmSZQ+TUn8DfmIDgh3ju70sHzNonuv/5QvInrFJqZVGBmXv4MPQLjr20Bt60 dW6kOVdhg65Ug== From: Andreas Hindborg To: Boqun Feng Cc: Alice Ryhl , Lorenzo Stoakes , "Liam R. Howlett" , Miguel Ojeda , Boqun Feng , Gary Guo , =?utf-8?Q?Bj=C3=B6rn?= Roy Baron , Benno Lossin , Trevor Gross , Danilo Krummrich , Will Deacon , Peter Zijlstra , Mark Rutland , linux-mm@kvack.org, rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] rust: page: add byte-wise atomic memory copy methods In-Reply-To: <87ikc1ubuy.fsf@kernel.org> References: <20260212-page-volatile-io-v2-1-a36cb97d15c2@kernel.org> <87ikc1ubuy.fsf@kernel.org> Date: Thu, 12 Feb 2026 18:23:36 +0100 Message-ID: <87ecmpub8n.fsf@kernel.org> MIME-Version: 1.0 Content-Type: text/plain X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: C3F94100005 X-Stat-Signature: 8mxxgqrendh7kiq3z9nnucmshjte3759 X-Rspam-User: X-HE-Tag: 1770917024-155077 X-HE-Meta: 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 NeexljmX IEE8gMafWBUHEF+pY3mb+e5YPcX5vd2vKuKnhS3MC18fwfAlebmTb1Edp6NDCqlYLaHbQSyv5Qks6unNm/mnqXPavUEstjmIxgz/MgUCYG4EVi/QZwiisL1Q0WVWm0zEW3slFasGdKXvei3Nvb/X+tAiBq/CcbeWmU5TGbpXFn50vXiYZyXkDdSyYJfaddk+oPsbJhRo12WOPA8LSJGuYMfEtC7c+qnEd3kR48xaUWEdk+XyZYtSOuQql2ad27QEHGuVKcKsJjGhjuobafwVaUJOdu4kIszULAXGmYc5JSqJ6l+0= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Andreas Hindborg writes: > "Boqun Feng" writes: > >> On Thu, Feb 12, 2026 at 03:51:24PM +0100, Andreas Hindborg wrote: >>> When copying data from buffers that are mapped to user space, it is >>> impossible to guarantee absence of concurrent memory operations on those >>> buffers. Copying data to/from `Page` from/to these buffers would be >>> undefined behavior if no special considerations are made. >>> >>> Add methods on `Page` to read and write the contents using byte-wise atomic >>> operations. >>> >> >> Thank you, but in this patch we still have "the given IO memory" and use >> memcpy_{from,to}io() as the implementation, is that intended? > > No that is a mistake. Please pretend it is regular `memcpy`. I'll send > v3 soon. Sorry, pretend it is `kernel::sync::atomic_per_byte_memcpy` ofc. Best regards, Andreas Hindborg