Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752576AbdLKJDJ (ORCPT ); Mon, 11 Dec 2017 04:03:09 -0500 Received: from mx2.suse.de ([195.135.220.15]:59056 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750836AbdLKJDG (ORCPT ); Mon, 11 Dec 2017 04:03:06 -0500 Date: Mon, 11 Dec 2017 10:03:03 +0100 From: Michal Hocko To: John Hubbard Cc: Michael Kerrisk , linux-man , linux-api@vger.kernel.org, Michael Ellerman , linux-mm@kvack.org, LKML , linux-arch@vger.kernel.org, Jann Horn , Matthew Wilcox , Mike Rapoport , Cyril Hrubis Subject: Re: [PATCH v4] mmap.2: MAP_FIXED updated documentation Message-ID: <20171211090303.GG20234@dhcp22.suse.cz> References: <20171206031434.29087-1-jhubbard@nvidia.com> <20171210103147.GC20234@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.1 (2017-09-22) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1689 Lines: 44 On Sun 10-12-17 18:22:05, John Hubbard wrote: > On 12/10/2017 02:31 AM, Michal Hocko wrote: > > On Tue 05-12-17 19:14:34, john.hubbard@gmail.com wrote: > >> From: John Hubbard > >> > >> Previously, MAP_FIXED was "discouraged", due to portability > >> issues with the fixed address. In fact, there are other, more > >> serious issues. Also, alignment requirements were a bit vague. > >> So: > >> > >> -- Expand the documentation to discuss the hazards in > >> enough detail to allow avoiding them. > >> > >> -- Mention the upcoming MAP_FIXED_SAFE flag. > >> > >> -- Enhance the alignment requirement slightly. > >> > >> Some of the wording is lifted from Matthew Wilcox's review > >> (the "Portability issues" section). The alignment requirements > >> section uses Cyril Hrubis' wording, with light editing applied. > >> > >> Suggested-by: Matthew Wilcox > >> Suggested-by: Cyril Hrubis > >> Signed-off-by: John Hubbard > > > > Would you mind if I take this patch and resubmit it along with my > > MAP_FIXED_SAFE (or whatever name I will end up with) next week? > > > > Acked-by: Michal Hocko > > Sure, that works for me. A tiny complication: I see that Michael > Kerrisk has already applied the much smaller v2 of this patch (the > one that "no longer discourages" the option, but that's all), as: > > ffa518803e14 mmap.2: MAP_FIXED is no longer discouraged > > so this one here will need to be adjusted slightly to merge > gracefully. Let me know if you want me to respin, or if you > want to handle the merge. Yes, please respin. -- Michal Hocko SUSE Labs