From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756056Ab2BAJCY (ORCPT ); Wed, 1 Feb 2012 04:02:24 -0500 Received: from mail-pw0-f46.google.com ([209.85.160.46]:58997 "EHLO mail-pw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754676Ab2BAJCP convert rfc822-to-8bit (ORCPT ); Wed, 1 Feb 2012 04:02:15 -0500 MIME-Version: 1.0 In-Reply-To: <20120201.024357.1370213516985704222.davem@davemloft.net> References: <20120131.190830.1189531706541596294.davem@davemloft.net> <20120201.024357.1370213516985704222.davem@davemloft.net> From: =?ISO-8859-2?Q?=A9tefan_Gula?= Date: Wed, 1 Feb 2012 10:01:55 +0100 X-Google-Sender-Auth: fDdItfAA47lscldrrEO03kSVUc0 Message-ID: Subject: Re: [patch v7, kernel version 3.2.1] net/ipv4/ip_gre: Ethernet multipoint GRE over IP To: David Miller Cc: kuznet@ms2.inr.ac.ru, jmorris@namei.org, yoshfuji@linux-ipv6.org, kaber@trash.net, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2012/2/1 David Miller : > From: Štefan Gula > Date: Wed, 1 Feb 2012 08:22:02 +0100 > >> So if this is now only about the >> maintenance of my code, I'll be more than happy to continue >> maintaining it myself together with you guys. > > You have a very warped understanding of what maintainence cost means. > > Everyone time someone wants to change a core API in the networking > your new code will need to be considered.  Every time someone wants to > audit how an interface is used, your code adds to the audit burdon. That's true. But as I said. gretap interface already exists in linux kernel. Without my patch it simply use logic of point-to-point tunnel or static point-to-multipoint tunnel using muticast IP address as destination. The point here is that the maintenance cost is there already: >>From the kernel API point of view the functions that enables use of gre or gretap interface are already there maintained (functions like init/exit/xmit/receive...). That part of the code was modified as little as possible. If that kernel API changes, the API will need to be changed also for standard gre or gretap code, which in the end almost the same amount of time consumed to figure out the code as it is the same functions that are called. >>From the user-space/netlink API point of view those functions (open/close/add/change/del....) are already maintained - my patch allows you to use only one additional keyword "bridge" to maintain backward compatibility, so if that part of API changes, it influences again whole gre/gretap API and therefore almost the same amount of code is needed to be checked. The last portion of auditing the code purpose is that you are developing something new that doesn't exists or try to port the code to somewhere else. In that time we are talking about maintaining the gre/gretap code itself and not some global API changes - that's the only one relevant where more time is needed, but this one is expected (at least should be by developer) If I missed something, please feel free to highlight it. > > And this is burdon placed upon other people, even if you personally > "promise" to maintain this specific code snippet.  This promise > completely meaningless from a global kernel maintainence standpoint. Yes, the burdon is there, but it's minimal from global point of view. > Therefore we don't add spurious code, and your code is spurious if it > will end up duplicating a more desirable implementation and interface > for this functionality. It cannot duplicate something that doesn't actually currently exists. VXLAN or NVGRE are still in process of developing/designing, so in the end it could easily happen that those "standards" will not do the same thing or by the same methodology - it's completely on those developers/designers, if they adopt my implementation/design or use something else. Openvswitch gre interface is currently only the same as thing as is current gretap interface in linux kernel with some kind of caching code - nothing more.