From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sat, 10 Nov 2001 13:00:06 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sat, 10 Nov 2001 12:59:57 -0500 Received: from nat-pool-meridian.redhat.com ([199.183.24.200]:17506 "EHLO devserv.devel.redhat.com") by vger.kernel.org with ESMTP id ; Sat, 10 Nov 2001 12:59:43 -0500 Date: Sat, 10 Nov 2001 12:58:32 -0500 From: Pete Zaitcev To: Ulrich Weigand Cc: linux-kernel@vger.kernel.org, Pete Zaitcev Subject: Re: Patch for kernel.real-root-dev on s390 Message-ID: <20011110125832.A21437@devserv.devel.redhat.com> In-Reply-To: <200111100248.DAA00341@faui11.informatik.uni-erlangen.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: <200111100248.DAA00341@faui11.informatik.uni-erlangen.de>; from weigand@immd1.informatik.uni-erlangen.de on Sat, Nov 10, 2001 at 03:48:33AM +0100 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > From: Ulrich Weigand > Date: Sat, 10 Nov 2001 03:48:33 +0100 (MET) > Cc: linux-kernel@vger.kernel.org > I agree that this looks broken, but I don't see why it > would be s390 specific. The clobber of adjacent memory > happens on all architectures, and on all big endian systems > the value read is incorrect even if adjacent memory happens > to be 0. Probably alignment restrictions do not allow anything interesting to happen. I know now that ppc people complained about it. > However, I'm not convinced the patch is a proper fix; it > will cause the MAJOR and MINOR macros to be applied to a > variable not of type kdev_t, which happens to work now but will > break if the definition of kdev_t is changed to a structure > or pointer type (as it probably will at some point in the > future, if I recall the various discussions correctly). > > What about either > - adding support for kdev_t values to procfs > or I thought that would be the right thing to do when kdev_t is changed. Currently, I do not know how to change it. Guy Streeter told me that someone floated an insanely ugly patch that special-cased shorts into do_proc_dointvec(), and I did not like that approach too much. Once the structure of new kdev_t is known, the do_proc_kdev_t may be defined, but I think it makes no sense to jump the gun now. > - keeping two int variables real_root_major and > real_root_minor ? Who knows if we are going to have majors and minors at all. Suppose Gooch and Viro give us a decent devfs, or something. An alternative may be to redo the initrd interface, for instance have /proc/real-root-path instead of real-root-dev (and no sysctl), I did not have time to explore all implications of that way. -- Pete