From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2992687AbXDTJJK (ORCPT ); Fri, 20 Apr 2007 05:09:10 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S2992723AbXDTJJK (ORCPT ); Fri, 20 Apr 2007 05:09:10 -0400 Received: from mtagate2.de.ibm.com ([195.212.29.151]:50855 "EHLO mtagate2.de.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2992687AbXDTJJI (ORCPT ); Fri, 20 Apr 2007 05:09:08 -0400 Date: Fri, 20 Apr 2007 11:11:46 +0200 From: Cornelia Huck To: Tejun Heo Cc: Alan Stern , linux-kernel , Greg K-H , Rusty Russell , Dmitry Torokhov Subject: Re: [PATCH RFD] alternative kobject release wait mechanism Message-ID: <20070420111146.2c2e8192@gondolin.boeblingen.de.ibm.com> In-Reply-To: <46284F2A.4000401@gmail.com> References: <46284F2A.4000401@gmail.com> Organization: IBM Deutschland Entwicklung GmbH X-Mailer: Claws Mail 2.8.0 (GTK+ 2.8.20; i486-pc-linux-gnu) X-Legal: IBM Deutschland Entwicklung GmbH Vorsitzender des Aufsichtsrats: Johann Weihen =?ISO-8859-15?Q?Gesch=E4ftsf=FChrung:?= Herbert Kircher Sitz der Gesellschaft: =?ISO-8859-15?Q?B=F6blingen?= Registergericht: Amtsgericht Stuttgart, HRB 243294 Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 20 Apr 2007 14:27:06 +0900, Tejun Heo wrote: > Hello, Alan. > > Alan Stern wrote: > > This doesn't solve a related problem: a subsystem wants to register > > devices and to provide a set of mutually-exclusive services to the > > devices' drivers. The mutual exclusion has to be provided by a mutex or > > something similar, and the drivers need a way to unbind even while waiting > > to acquire the mutex. > > I don't really follow why the drivers need a way to unbind even while > waiting to acquire the mutex. Care to enlighten me? I guess when the driver is just being ripped out or an unbind has been triggered or similar. > Yeah, exactly. My argument is that that impedance matching between > lifetime rules must happen at some place and it's better if we can do in > the higher layer where we can afford more effort and thus complexity. > We're currently pushing that down to each drivers and not too many are > getting it right. I think it's just unrealistic to expect every and > each driver subsystems to get it right, so some overhead at higher layer > is acceptable and we can definitely afford much more optimization at > higher layer. I agree. It isn't easy to get this right, so just we should just solve that once for all drivers.