From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1764355AbXJOBkx (ORCPT ); Sun, 14 Oct 2007 21:40:53 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755304AbXJOBko (ORCPT ); Sun, 14 Oct 2007 21:40:44 -0400 Received: from mx1.redhat.com ([66.187.233.31]:53434 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755050AbXJOBkm (ORCPT ); Sun, 14 Oct 2007 21:40:42 -0400 Date: Mon, 15 Oct 2007 02:26:21 +0100 From: Alasdair G Kergon To: Arnd Bergmann Cc: Linus Torvalds , dm-devel@redhat.com, linux-kernel@vger.kernel.org, Milan Broz , Guido Guenther , Kevin Corry , stable@kernel.org Subject: Re: [2.6.24 PATCH 02/25] dm io:ctl use constant struct size Message-ID: <20071015012621.GD10006@agk.fab.redhat.com> Mail-Followup-To: Arnd Bergmann , Linus Torvalds , dm-devel@redhat.com, linux-kernel@vger.kernel.org, Milan Broz , Guido Guenther , Kevin Corry , stable@kernel.org References: <20071012170509.GM24157@agk.fab.redhat.com> <200710130016.29937.arnd@arndb.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200710130016.29937.arnd@arndb.de> User-Agent: Mutt/1.4.1i Organization: Red Hat UK Ltd. Registered in England and Wales, number 03798903. Registered Office: Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SL4 1TE. Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Oct 13, 2007 at 12:16:29AM +0200, Arnd Bergmann wrote: > This change seems rather bogus, you're changing the ABI just to work > around a bug in the compat_ioctl layer. Why not just do the compat > code the right way, like the patch below? The underlying ABI is not changing, I hope - the trailing padding in the struct should not affect the processing of the data by dm, and I see no reason to continue maintaining the fiction that the 32-bit and 64-bit ioctls are in some way incompatible with each other when they aren't AFAIK. And yes, a follow-up patch can clean up our use of the compatibility mechanism, going a little bit further than the patch you attached, I hope. Alasdair -- agk@redhat.com