From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932258Ab1EXNNG (ORCPT ); Tue, 24 May 2011 09:13:06 -0400 Received: from smtp4-g21.free.fr ([212.27.42.4]:44583 "EHLO smtp4-g21.free.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932222Ab1EXNNF (ORCPT ); Tue, 24 May 2011 09:13:05 -0400 From: Florian Fainelli Organization: Freebox To: Greg KH Subject: Re: [PATCH] TTY: export NR_LDISC and N_* line discipline numbers to user-space Date: Tue, 24 May 2011 15:17:23 +0200 User-Agent: KMail/1.13.6 (Linux/2.6.38-8-server; KDE/4.6.2; x86_64; ; ) Cc: lkml , Maxime Bizon , Tilman Schmidt , Andrew Morton References: <201105241043.03347.ffainelli@freebox.fr> <20110524124044.GD31517@suse.de> In-Reply-To: <20110524124044.GD31517@suse.de> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201105241517.23166.ffainelli@freebox.fr> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, On Tuesday 24 May 2011 14:40:44 Greg KH wrote: > On Tue, May 24, 2011 at 10:43:03AM +0200, Florian Fainelli wrote: > > From: Florian Fainelli > > > > Since commit (4564f9e5: consolidate line discipline number definitions) > > the patch moved all line discipline number from a per-architecture > > termios.h to a shared one: tty.h. However, prior to this consolidation > > work, the line discipline numbers were outside of an ifdef > > __KERNEL__/endif block so these numbers used to be exported to > > user-space. > > > > Since such numbers are kernel ABI anyway, and tty.h is already included > > for user- space header processing, just move these relevant defines > > outside of the ifdef __KERNEL__/endif block in include/linux/tty.h. > > Any reason you didn't copy _any_ of the people who signed off on that > patch, or the original author of that patch? No particular reason but my mistake, fixed that. > > Anyway, this is been this way for four years, since the 2.6.21 kernel > release. Since no one has noticed, or complained, since then, how much > a problem is this really? This is a problem because you may have out of tree drivers using a line discpline number, and you do not want your companion user-space application to have to use a different line discpline number but the one the kernel should provide. > > Meaning, why has it taken this long for anyone to notice? - long standing user-space applications such as pppd got their N_PPP long ago, and do not have to worry about N_PPP being renumbered so they can just define it in pppd's sources it won't break - I started implementing a line discipline driver only a couple of months ago and then realized that such ABI should have been exported -- Florian