From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261458AbVG1ORO (ORCPT ); Thu, 28 Jul 2005 10:17:14 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261472AbVG1ORI (ORCPT ); Thu, 28 Jul 2005 10:17:08 -0400 Received: from pentafluge.infradead.org ([213.146.154.40]:42634 "EHLO pentafluge.infradead.org") by vger.kernel.org with ESMTP id S261468AbVG1ORA (ORCPT ); Thu, 28 Jul 2005 10:17:00 -0400 Date: Thu, 28 Jul 2005 15:16:53 +0100 From: Christoph Hellwig To: Stephen Rothwell Cc: LKML , Andrew Morton Subject: Re: [PATCH] compat_sys_read/write Message-ID: <20050728141653.GA22173@infradead.org> Mail-Followup-To: Christoph Hellwig , Stephen Rothwell , LKML , Andrew Morton References: <20050728234341.3303d5fe.sfr@canb.auug.org.au> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20050728234341.3303d5fe.sfr@canb.auug.org.au> User-Agent: Mutt/1.4.2.1i X-SRS-Rewrite: SMTP reverse-path rewritten from by pentafluge.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jul 28, 2005 at 11:43:41PM +1000, Stephen Rothwell wrote: > Hi all, > > Someone mentioned the mess in evdev.c that is caused by the fact that the > structures that are passed to/from user mode via read/write require > conversion when this API is used from 32 bit tasks on 64 bit kernels. > Some "discussion" followed during which I suggested an idea originally > from Matthew Wilcox of an arch-specific is_compat_task() function so that > these places could be identified. However it was considered better to > instead implement compat_sys_read/write. This looks totally horrible, especially as we'd need readv/writev and pread/pwrite aswell. I don't think anyone but Andi actually liked this approach when discussed earlier.