From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <SRS0=lzY1=6F=kvack.org=owner-linux-mm@kernel.org>
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=HEADER_FROM_DIFFERENT_DOMAINS,
	MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 D968EC54FC9
	for <linux-mm@archiver.kernel.org>; Tue, 21 Apr 2020 15:30:00 +0000 (UTC)
Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17])
	by mail.kernel.org (Postfix) with ESMTP id A8D72206A2
	for <linux-mm@archiver.kernel.org>; Tue, 21 Apr 2020 15:30:00 +0000 (UTC)
DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A8D72206A2
Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=zeniv.linux.org.uk
Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org
Received: by kanga.kvack.org (Postfix)
	id 42E728E0005; Tue, 21 Apr 2020 11:30:00 -0400 (EDT)
Received: by kanga.kvack.org (Postfix, from userid 40)
	id 3DD878E0003; Tue, 21 Apr 2020 11:30:00 -0400 (EDT)
X-Delivered-To: int-list-linux-mm@kvack.org
Received: by kanga.kvack.org (Postfix, from userid 63042)
	id 31AE88E0005; Tue, 21 Apr 2020 11:30:00 -0400 (EDT)
X-Delivered-To: linux-mm@kvack.org
Received: from forelay.hostedemail.com (smtprelay0176.hostedemail.com [216.40.44.176])
	by kanga.kvack.org (Postfix) with ESMTP id 1AEC88E0003
	for <linux-mm@kvack.org>; Tue, 21 Apr 2020 11:30:00 -0400 (EDT)
Received: from smtpin10.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251])
	by forelay01.hostedemail.com (Postfix) with ESMTP id C89F8180AD820
	for <linux-mm@kvack.org>; Tue, 21 Apr 2020 15:29:59 +0000 (UTC)
X-FDA: 76732247718.10.actor54_91741485c1062
X-HE-Tag: actor54_91741485c1062
X-Filterd-Recvd-Size: 1707
Received: from ZenIV.linux.org.uk (zeniv.linux.org.uk [195.92.253.2])
	by imf44.hostedemail.com (Postfix) with ESMTP
	for <linux-mm@kvack.org>; Tue, 21 Apr 2020 15:29:59 +0000 (UTC)
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 <viro@zeniv.linux.org.uk>
To: Catalin Marinas <catalin.marinas@arm.com>
Cc: linux-arm-kernel@lists.infradead.org, Will Deacon <will@kernel.org>,
	Vincenzo Frascino <vincenzo.frascino@arm.com>,
	Szabolcs Nagy <szabolcs.nagy@arm.com>,
	Richard Earnshaw <Richard.Earnshaw@arm.com>,
	Kevin Brodsky <kevin.brodsky@arm.com>,
	Andrey Konovalov <andreyknvl@google.com>,
	Peter Collingbourne <pcc@google.com>, linux-mm@kvack.org,
	linux-arch@vger.kernel.org
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-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20200421142603.3894-21-catalin.marinas@arm.com>
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: <linux-mm.kvack.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.