Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S967470AbXEHAKn (ORCPT ); Mon, 7 May 2007 20:10:43 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S967464AbXEHAKm (ORCPT ); Mon, 7 May 2007 20:10:42 -0400 Received: from mx1.redhat.com ([66.187.233.31]:49738 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S967463AbXEHAKk (ORCPT ); Mon, 7 May 2007 20:10:40 -0400 Message-ID: <463FBF69.3040203@redhat.com> Date: Mon, 07 May 2007 20:08:09 -0400 From: =?UTF-8?B?S3Jpc3RpYW4gSMO4Z3NiZXJn?= User-Agent: Thunderbird 1.5.0.10 (X11/20070302) MIME-Version: 1.0 To: Christoph Hellwig , Stefan Richter , linux-kernel@vger.kernel.org, Kristian H??gsberg , Linus Torvalds , Andrew Morton , linux1394-devel Subject: Re: [PATCH 3/6] firewire: char device interface References: <4637A29F.6070302@redhat.com> <20070502090007.GA28174@infradead.org> <20070502193026.GC1248@infradead.org> In-Reply-To: <20070502193026.GC1248@infradead.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1338 Lines: 35 Christoph Hellwig wrote: > On Wed, May 02, 2007 at 02:17:26PM +0200, Stefan Richter wrote: >> +#include >> +#include > > Always use the > +struct fw_cdev_get_info { >> + /* The version field is just a running serial number. We >> + * never break backwards compatibility. Userspace passes in >> + * the version it expects and the kernel passes back the >> + * highest version it can provide. Even if the structs in >> + * this interface are extended in a later version, the kernel >> + * will not copy back more data than what was present in the >> + * interface version userspace expects. */ >> + __u32 version; > > Please don't even try to build interfaces this complicated. If your > current interface needs changes at some point just introduce new ioctls. Sure, I don't expect a lot of changes anyway, and the few features I know that will show up down the road are strictly additions anyway. I think it makes sense to keep the version number there, though, as a way to advertise which ioctls are present. Kristian - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/