From mboxrd@z Thu Jan 1 00:00:00 1970 From: Al Viro Subject: Re: [PATCH v3 20/23] fs: Allow copy_mount_options() to access user-space in a single pass Date: Tue, 21 Apr 2020 16:29:48 +0100 Message-ID: <20200421152948.GC23230@ZenIV.linux.org.uk> References: <20200421142603.3894-1-catalin.marinas@arm.com> <20200421142603.3894-21-catalin.marinas@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57898 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725870AbgDUPaC (ORCPT ); Tue, 21 Apr 2020 11:30:02 -0400 Received: from ZenIV.linux.org.uk (zeniv.linux.org.uk [IPv6:2002:c35c:fd02::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 27DB5C061A10 for ; Tue, 21 Apr 2020 08:30:02 -0700 (PDT) Content-Disposition: inline In-Reply-To: <20200421142603.3894-21-catalin.marinas@arm.com> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Catalin Marinas Cc: linux-arm-kernel@lists.infradead.org, Will Deacon , Vincenzo Frascino , Szabolcs Nagy , Richard Earnshaw , Kevin Brodsky , Andrey Konovalov , Peter Collingbourne , linux-mm@kvack.org, linux-arch@vger.kernel.org On Tue, Apr 21, 2020 at 03:26:00PM +0100, Catalin Marinas wrote: > While this function is not on a critical path, the single-pass behaviour > is required for arm64 MTE (memory tagging) support where a uaccess can > trigger intra-page faults (tag not matching). With the current > implementation, if this happens during the first page, the function will > return -EFAULT. Details, please. 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 X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2F1C8C54FCC for ; Tue, 21 Apr 2020 15:30:11 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id B510E206E9 for ; Tue, 21 Apr 2020 15:30:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="Exy+TYZh" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B510E206E9 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=zeniv.linux.org.uk Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=SJL2MNZk2bO7Wl3NP7GOfLTUGaMPJohMtmpV1hW5pro=; b=Exy+TYZhgeiymz sH6s8RVHW/GhS0S8vrCHurTg6HlUzUUOnFI1Ej66Djj5jUWis/yTJSJKxLau2x4gwVSpZHs4hu8nf zjzKZ98Qf9phAHk8OE57TSyII79pynir5Ri6cJJyf8hqYxcIME+S/83a3umH9/yhZiSsBctnyvfIE nQFCDS/JCHt0iflZc1hni33ztuFrapkuiVIZVQVM86BQYYfjG5kSa0n0OsVrIjrUmNY6/QAQnr0xG BZIYMsTrftnaK9nQgCZjSjHQpuRE0e9j+tuxPUiEkiGYj0Kz8XsS0WVDlqJ4+V3UFgnYtHWrDFu/n KLTI2g2/PpIxXYEFpR0A==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jQuqc-0005yh-Mj; Tue, 21 Apr 2020 15:30:06 +0000 Received: from [2002:c35c:fd02::1] (helo=ZenIV.linux.org.uk) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jQuqX-00056H-79 for linux-arm-kernel@lists.infradead.org; Tue, 21 Apr 2020 15:30:04 +0000 Received: from viro by ZenIV.linux.org.uk with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1jQuqK-007fHW-VB; Tue, 21 Apr 2020 15:29:49 +0000 Date: Tue, 21 Apr 2020 16:29:48 +0100 From: Al Viro To: Catalin Marinas Subject: Re: [PATCH v3 20/23] fs: Allow copy_mount_options() to access user-space in a single pass Message-ID: <20200421152948.GC23230@ZenIV.linux.org.uk> References: <20200421142603.3894-1-catalin.marinas@arm.com> <20200421142603.3894-21-catalin.marinas@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200421142603.3894-21-catalin.marinas@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200421_083002_269728_E2484882 X-CRM114-Status: UNSURE ( 7.32 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-arch@vger.kernel.org, Richard Earnshaw , Szabolcs Nagy , Andrey Konovalov , Kevin Brodsky , Peter Collingbourne , linux-mm@kvack.org, Vincenzo Frascino , Will Deacon , linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Apr 21, 2020 at 03:26:00PM +0100, Catalin Marinas wrote: > While this function is not on a critical path, the single-pass behaviour > is required for arm64 MTE (memory tagging) support where a uaccess can > trigger intra-page faults (tag not matching). With the current > implementation, if this happens during the first page, the function will > return -EFAULT. Details, please. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel