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=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 0A1F8C433DF for ; Thu, 28 May 2020 19:01:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EA2DE2074B for ; Thu, 28 May 2020 19:01:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2406097AbgE1TBA (ORCPT ); Thu, 28 May 2020 15:01:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56168 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2406018AbgE1TA7 (ORCPT ); Thu, 28 May 2020 15:00:59 -0400 Received: from ZenIV.linux.org.uk (zeniv.linux.org.uk [IPv6:2002:c35c:fd02::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5CC5DC08C5C6; Thu, 28 May 2020 12:00:59 -0700 (PDT) Received: from viro by ZenIV.linux.org.uk with local (Exim 4.93 #3 (Red Hat Linux)) id 1jeNls-00H4Qd-Rj; Thu, 28 May 2020 19:00:53 +0000 Date: Thu, 28 May 2020 20:00:52 +0100 From: Al Viro To: Christoph Hellwig Cc: Linus Torvalds , Ian Kent , David Howells , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-security-module@vger.kernel.org, netfilter-devel@vger.kernel.org Subject: Re: [PATCH 09/14] fs: don't change the address limit for ->write_iter in __kernel_write Message-ID: <20200528190052.GM23230@ZenIV.linux.org.uk> References: <20200528054043.621510-1-hch@lst.de> <20200528054043.621510-10-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200528054043.621510-10-hch@lst.de> Sender: netfilter-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org On Thu, May 28, 2020 at 07:40:38AM +0200, Christoph Hellwig wrote: > If we write to a file that implements ->write_iter there is no need > to change the address limit if we send a kvec down. Implement that > case, and prefer it over using plain ->write with a changed address > limit if available. Umm... It needs a comment along the lines of "weird shits like /dev/sg that currently check for uaccess_kernel() will just have to make sure they never switch to ->write_iter()"