From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755149AbXDZViI (ORCPT ); Thu, 26 Apr 2007 17:38:08 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755150AbXDZViI (ORCPT ); Thu, 26 Apr 2007 17:38:08 -0400 Received: from moutng.kundenserver.de ([212.227.126.177]:51847 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755149AbXDZViG (ORCPT ); Thu, 26 Apr 2007 17:38:06 -0400 From: Arnd Bergmann To: Paul Fulghum Subject: Re: compat_ioctl question Date: Thu, 26 Apr 2007 23:37:55 +0200 User-Agent: KMail/1.9.6 Cc: Linux Kernel Mailing List References: <1177620717.5060.11.camel@amdx2.microgate.com> In-Reply-To: <1177620717.5060.11.camel@amdx2.microgate.com> X-Face: >j"dOR3XO=^3iw?0`(E1wZ/&le9!.ok[JrI=S~VlsF~}"P\+jx.GT@=?utf-8?q?=0A=09-oaEG?=,9Ba>v;3>:kcw#yO5?B:l{(Ln.2)=?utf-8?q?=27=7Dfw07+4-=26=5E=7CScOpE=3F=5D=5EXdv=5B/zWkA7=60=25M!DxZ=0A=09?= =?utf-8?q?8MJ=2EU5?="hi+2yT(k`PF~Zt;tfT,i,JXf=x@eLP{7B:"GyA\=UnN) =?utf-8?q?=26=26qdaA=3A=7D-Y*=7D=3A3YvzV9=0A=09=7E=273a=7E7I=7CWQ=5D?=<50*%U-6Ewmxfzdn/CK_E/ouMU(r?FAQG/ev^JyuX.%(By`" =?utf-8?q?L=5F=0A=09H=3Dbj?=)"y7*XOqz|SS"mrZ$`Q_syCd MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-15" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200704262337.56240.arnd@arndb.de> X-Provags-ID: V01U2FsdGVkX1/4HzXH2vsu6IyFC7cwxMmhF7Ny4IFtLivJy76 RXzvneBjAujzbGyU3AavG3MnbXrQFK9uAKlB4H+JCs2NF5uSWj 2nQ+mvvr+JAj2OYnxcDOw== Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thursday 26 April 2007, Paul Fulghum wrote: > I need to add ioctl translations for my driver to > allow 32 bit access on 64 bit systems. > > After digging through the kernel code there seems to be > 3 methods of doing this: > > 1. define compat_ioctl() file operation for device and > implement translation code in individual driver > 2. add COMPATIBLE_IOCTL entry to include/linux/compat_ioctl.h > to mark an ioctl code as the same in any environment > 3. add HANDLE_IOCTL entry to fs/compat_ioctl.c with translation code > implemented in the same file > > There is no way to implement #1 for a tty driver without > modifying the kernel tty code to allow registration of a > compat_ioctl() handler. > > #3 would put a lot of driver specific stuff in a common > kernel file. This method also seems to break if there > is an ioctl code collision. > > All of these methods involve changes to code outside of my driver. > > -- > > Before I spend a lot of time on this I need to know what the > officially sanctioned method is. I haven't found any definitive > documentation and a review of mailing list archives does not > suggest a prevailing opinion. > > Does anyone have pointers on which way would be most likely > to be accepted as a patch? It depends a lot on what your specific driver does in the ioctl handler, but normally you should define a compat_ioctl() function. What driver are you talking about? Arnd <><