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=-3.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,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 33745C33CB1 for ; Tue, 14 Jan 2020 12:52:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 985CF207E0 for ; Tue, 14 Jan 2020 12:52:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=wp.pl header.i=@wp.pl header.b="lZPhlWcV" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726379AbgANMwC (ORCPT ); Tue, 14 Jan 2020 07:52:02 -0500 Received: from mx3.wp.pl ([212.77.101.10]:19597 "EHLO mx3.wp.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726175AbgANMwC (ORCPT ); Tue, 14 Jan 2020 07:52:02 -0500 Received: (wp-smtpd smtp.wp.pl 30740 invoked from network); 14 Jan 2020 13:51:57 +0100 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=wp.pl; s=1024a; t=1579006317; bh=kSC9TeFUobiO3Iz/cyDPdWPcN3QsQfg0WTbYeDOz+PU=; h=From:To:Cc:Subject; b=lZPhlWcVJ2DsliFxcUNtxkmqSMEeO9Yfdrsah7E1tx25EE4F2AHXd2Fj4V9xskmf+ r43qlGV5WNpg3+chbg5Kd2RjOFA6Flv4OjWY7kPX1yxn9jcajiy9OclOtFr1G+vYQH DVQLH3FYL+7h7PVIuXbxvjCIrVIf3NPdS88/QMg8= Received: from c-73-93-4-247.hsd1.ca.comcast.net (HELO cakuba) (kubakici@wp.pl@[73.93.4.247]) (envelope-sender ) by smtp.wp.pl (WP-SMTPD) with ECDHE-RSA-AES256-GCM-SHA384 encrypted SMTP for ; 14 Jan 2020 13:51:57 +0100 Date: Tue, 14 Jan 2020 04:51:49 -0800 From: Jakub Kicinski To: Martin Schiller Cc: khc@pm.waw.pl, davem@davemloft.net, linux-x25@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] wan/hdlc_x25: make lapb params configurable Message-ID: <20200114045149.4e97f0ac@cakuba> In-Reply-To: <83f60f76a0cf602c73361ccdb34cc640@dev.tdt.de> References: <20200113124551.2570-1-ms@dev.tdt.de> <20200113055316.4e811276@cakuba> <83f60f76a0cf602c73361ccdb34cc640@dev.tdt.de> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-WP-MailID: 107e775709673ca4f5508c7caa3a988f X-WP-AV: skaner antywirusowy Poczty Wirtualnej Polski X-WP-SPAM: NO 000000A [waMU] Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Tue, 14 Jan 2020 06:37:03 +0100, Martin Schiller wrote: > >> diff --git a/include/uapi/linux/hdlc/ioctl.h > >> b/include/uapi/linux/hdlc/ioctl.h > >> index 0fe4238e8246..3656ce8b8af0 100644 > >> --- a/include/uapi/linux/hdlc/ioctl.h > >> +++ b/include/uapi/linux/hdlc/ioctl.h > >> @@ -3,7 +3,7 @@ > >> #define __HDLC_IOCTL_H__ > >> > >> > >> -#define GENERIC_HDLC_VERSION 4 /* For synchronization with sethdlc > >> utility */ > >> +#define GENERIC_HDLC_VERSION 5 /* For synchronization with sethdlc > >> utility */ > > > > What's the backward compatibility story in this code? > > Well, I thought I have to increment the version to keep the kernel code > and the sethdlc utility in sync (like the comment says). Perhaps I chose the wrong place for asking this question, IOCTL code was my real worry. I don't think this version number is validated so I think bumping it shouldn't break anything? > > The IOCTL handling at least looks like it may start returning errors > > to existing user space which could have expected the parameters to > > IF_PROTO_X25 (other than just ifr_settings.type) to be ignored. > > I could also try to implement it without incrementing the version by > looking at ifr_settings.size and using the former defaults if the size > doesn't match. Sounds good, thank you!