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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 B5A12C4338F for ; Fri, 20 Aug 2021 12:39:40 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 436B0610CA for ; Fri, 20 Aug 2021 12:39:40 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 436B0610CA Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=1wt.eu Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id B91256B0071; Fri, 20 Aug 2021 08:39:39 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id B42566B0072; Fri, 20 Aug 2021 08:39:39 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A088F6B0073; Fri, 20 Aug 2021 08:39:39 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0204.hostedemail.com [216.40.44.204]) by kanga.kvack.org (Postfix) with ESMTP id 844F56B0071 for ; Fri, 20 Aug 2021 08:39:39 -0400 (EDT) Received: from smtpin22.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 2A9E682F2C21 for ; Fri, 20 Aug 2021 12:39:39 +0000 (UTC) X-FDA: 78495415278.22.2E53573 Received: from 1wt.eu (wtarreau.pck.nerim.net [62.212.114.60]) by imf22.hostedemail.com (Postfix) with ESMTP id 28E2D1904 for ; Fri, 20 Aug 2021 12:39:37 +0000 (UTC) Received: (from willy@localhost) by pcw.home.local (8.15.2/8.15.2/Submit) id 17KCcAgu024415; Fri, 20 Aug 2021 14:38:10 +0200 Date: Fri, 20 Aug 2021 14:38:10 +0200 From: Willy Tarreau To: Jeff Layton Cc: Amir Goldstein , Linus Torvalds , "Eric W. Biederman" , Matthew Wilcox , Andy Lutomirski , David Laight , David Hildenbrand , Linux Kernel Mailing List , Andrew Morton , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , Al Viro , Alexey Dobriyan , Steven Rostedt , "Peter Zijlstra (Intel)" , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Petr Mladek , Sergey Senozhatsky , Andy Shevchenko , Rasmus Villemoes , Kees Cook , Greg Ungerer , Geert Uytterhoeven , Mike Rapoport , Vlastimil Babka , Vincenzo Frascino , Chinwen Chang , Michel Lespinasse , Catalin Marinas , Huang Ying , Jann Horn , Feng Tang , Kevin Brodsky , Michael Ellerman , Shawn Anastasio , Steven Price , Nicholas Piggin , Christian Brauner , Jens Axboe , Gabriel Krisman Bertazi , Peter Xu , Suren Baghdasaryan , Shakeel Butt , Marco Elver , Daniel Jordan , Nicolas Viennot , Thomas Cedeno , Collin Fijalkovich , Michal Hocko , Miklos Szeredi , Chengguang Xu , Christian =?iso-8859-1?Q?K=F6nig?= , "linux-unionfs@vger.kernel.org" , Linux API , the arch/x86 maintainers , "" , Linux-MM , Florian Weimer , Michael Kerrisk Subject: Re: Removing Mandatory Locks Message-ID: <20210820123810.GE22171@1wt.eu> References: <87k0kkxbjn.fsf_-_@disp2133> <0c2af732e4e9f74c9d20b09fc4b6cbae40351085.camel@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) X-Rspamd-Queue-Id: 28E2D1904 Authentication-Results: imf22.hostedemail.com; dkim=none; dmarc=none; spf=pass (imf22.hostedemail.com: domain of w@1wt.eu designates 62.212.114.60 as permitted sender) smtp.mailfrom=w@1wt.eu X-Rspamd-Server: rspam04 X-Stat-Signature: shfxf3p48hzfmy6jh7z56c6k69d8wmfi X-HE-Tag: 1629463177-689903 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 Fri, Aug 20, 2021 at 08:27:12AM -0400, Jeff Layton wrote: > I'm fine with any of these approaches if the consensus is that it's too > risky to just remove it. OTOH, I've yet to ever hear of any application > that uses this feature, even in a historical sense. Honestly, I agree. Some have fun of me because I'm often using old stuff, but I don't even remember having used an application that made use of mandatory locking. I remember having enabled it myself in my kernels long ago after discovering its existence in the man pages, just to test it. It doesn't rule out the possibility that it exists somewhere though, but I think that the immediate removal combined with the big fat warning in previous branches should be largely enough to avoid the last minute surprise. Willy