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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 106D8C32750 for ; Fri, 2 Aug 2019 09:12:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D5415205F4 for ; Fri, 2 Aug 2019 09:12:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564737172; bh=JrP72r6LstQeI6Dz9wti4WjfN6tNHcW2sHlVYyQng/I=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=Z2yt5nEdvNzKruWu527OiGR+8Ok8FYLCbzvEkVPZbiT+wnIMmyLWrfbo8Oyu4gtgG Amkva43VMOviSY+TT+wUX7G6GszzfgAnc9HMzs0AG1ADlu2N1wRP1UOgmw5zRbpVpC 4gQs+isdjBTbNUeVkfIJOaBtMp8uuQKmjhB6oRKs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387799AbfHBJMv (ORCPT ); Fri, 2 Aug 2019 05:12:51 -0400 Received: from mx2.suse.de ([195.135.220.15]:54294 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727127AbfHBJMu (ORCPT ); Fri, 2 Aug 2019 05:12:50 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 4990DAFE2; Fri, 2 Aug 2019 09:12:47 +0000 (UTC) Date: Fri, 2 Aug 2019 11:12:44 +0200 From: Michal Hocko To: john.hubbard@gmail.com Cc: Andrew Morton , Christoph Hellwig , Dan Williams , Dave Chinner , Dave Hansen , Ira Weiny , Jan Kara , Jason Gunthorpe , =?iso-8859-1?B?Suly9G1l?= Glisse , LKML , amd-gfx@lists.freedesktop.org, ceph-devel@vger.kernel.org, devel@driverdev.osuosl.org, devel@lists.orangefs.org, dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-block@vger.kernel.org, linux-crypto@vger.kernel.org, linux-fbdev@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-media@vger.kernel.org, linux-mm@kvack.org, linux-nfs@vger.kernel.org, linux-rdma@vger.kernel.org, linux-rpi-kernel@lists.infradead.org, linux-xfs@vger.kernel.org, netdev@vger.kernel.org, rds-devel@oss.oracle.com, sparclinux@vger.kernel.org, x86@kernel.org, xen-devel@lists.xenproject.org, John Hubbard Subject: Re: [PATCH 00/34] put_user_pages(): miscellaneous call sites Message-ID: <20190802091244.GD6461@dhcp22.suse.cz> References: <20190802022005.5117-1-jhubbard@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190802022005.5117-1-jhubbard@nvidia.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu 01-08-19 19:19:31, john.hubbard@gmail.com wrote: [...] > 2) Convert all of the call sites for get_user_pages*(), to > invoke put_user_page*(), instead of put_page(). This involves dozens of > call sites, and will take some time. How do we make sure this is the case and it will remain the case in the future? There must be some automagic to enforce/check that. It is simply not manageable to do it every now and then because then 3) will simply be never safe. Have you considered coccinele or some other scripted way to do the transition? I have no idea how to deal with future changes that would break the balance though. -- Michal Hocko SUSE Labs