From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762756AbZJOPA7 (ORCPT ); Thu, 15 Oct 2009 11:00:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1762416AbZJOPA6 (ORCPT ); Thu, 15 Oct 2009 11:00:58 -0400 Received: from earthlight.etchedpixels.co.uk ([81.2.110.250]:49705 "EHLO www.etchedpixels.co.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1762297AbZJOPA5 (ORCPT ); Thu, 15 Oct 2009 11:00:57 -0400 Date: Thu, 15 Oct 2009 16:01:09 +0100 From: Alan Cox To: Jeff Garzik Cc: Thomas Gleixner , LKML , Arnd Bergmann , Ingo Molnar , Peter Zijlstra , Frederic Weisbecker Subject: Re: [RFC] Remove or convert empty ioctls ? Message-ID: <20091015160109.6d9353e8@lxorguk.ukuu.org.uk> In-Reply-To: <4AD711BC.2030409@garzik.org> References: <4AD711BC.2030409@garzik.org> X-Mailer: Claws Mail 3.7.2 (GTK+ 2.14.7; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > "no particular value" is highly subjective, and I think unprovable, > without an exhaustive survey of userland programs interacting with > kernel drivers. Userland programs often interact with a -class- of > drivers, expecting predictable behavior from a DoThisThing ioctl, with > EINVAL or "other weird error code" returned intentionally. > > Changing the return codes seems quite unwise. We've changed lots of them to -ENOTTY over the past few years, nobody has even noticed (you included ;)) SuS says an unknown ioctl code returns -ENOTTY. Alan