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=-3.8 required=3.0 tests=BAYES_00, 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 BC0A7C43465 for ; Mon, 21 Sep 2020 15:07:55 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 8472520BED for ; Mon, 21 Sep 2020 15:07:55 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8472520BED 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 0C1DC6B010E; Mon, 21 Sep 2020 11:07:55 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 01EDF6B0110; Mon, 21 Sep 2020 11:07:54 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id DDAFC6B010F; Mon, 21 Sep 2020 11:07:54 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0080.hostedemail.com [216.40.44.80]) by kanga.kvack.org (Postfix) with ESMTP id C3EF86B010E for ; Mon, 21 Sep 2020 11:07:54 -0400 (EDT) Received: from smtpin19.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 8774C181AEF10 for ; Mon, 21 Sep 2020 15:07:54 +0000 (UTC) X-FDA: 77287398468.19.care29_331298727146 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin19.hostedemail.com (Postfix) with ESMTP id 378E91AD1A3; Mon, 21 Sep 2020 15:07:54 +0000 (UTC) X-HE-Tag: care29_331298727146 X-Filterd-Recvd-Size: 2022 Received: from ZenIV.linux.org.uk (zeniv.linux.org.uk [195.92.253.2]) by imf11.hostedemail.com (Postfix) with ESMTP; Mon, 21 Sep 2020 15:07:53 +0000 (UTC) Received: from viro by ZenIV.linux.org.uk with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1kKNPt-003Bss-FQ; Mon, 21 Sep 2020 15:07:45 +0000 Date: Mon, 21 Sep 2020 16:07:45 +0100 From: Al Viro To: Christoph Hellwig Cc: Andrew Morton , Jens Axboe , Arnd Bergmann , David Howells , David Laight , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, sparclinux@vger.kernel.org, linux-block@vger.kernel.org, linux-scsi@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-aio@kvack.org, io-uring@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, netdev@vger.kernel.org, keyrings@vger.kernel.org, linux-security-module@vger.kernel.org Subject: Re: [PATCH 04/11] iov_iter: explicitly check for CHECK_IOVEC_ONLY in rw_copy_check_uvector Message-ID: <20200921150745.GT3421308@ZenIV.linux.org.uk> References: <20200921143434.707844-1-hch@lst.de> <20200921143434.707844-5-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200921143434.707844-5-hch@lst.de> 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: On Mon, Sep 21, 2020 at 04:34:27PM +0200, Christoph Hellwig wrote: > Explicitly check for the magic value insted of implicitly relying on > its numeric representation. Also drop the rather pointless unlikely > annotation. See above - I would rather have CHECK_IOVEC_ONLY gone. The reason for doing these access_ok() in the same loop is fairly weak, especially since you are checking type on each iteration. Might as well do that in a separate loop afterwards.