Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757339Ab0KJXPj (ORCPT ); Wed, 10 Nov 2010 18:15:39 -0500 Received: from 124x34x33x190.ap124.ftth.ucom.ne.jp ([124.34.33.190]:43246 "EHLO master.linux-sh.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753973Ab0KJXPg (ORCPT ); Wed, 10 Nov 2010 18:15:36 -0500 Date: Thu, 11 Nov 2010 08:15:08 +0900 From: Paul Mundt To: Greg KH Cc: Grant Likely , Thomas Gleixner , Maciej Szmigiero , linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, Anton Vorontsov , Uwe Kleine-K?nig , Andrew Morton , Arnd Bergmann , Jonathan Cameron , Ben Nizette Subject: Re: [GPIO]implement sleeping GPIO chip removal Message-ID: <20101110231507.GA6758@linux-sh.org> References: <4CD6F049.10102@o2.pl> <20101110050947.GC4110@angua.secretlab.ca> <4CDABA03.2050000@o2.pl> <4CDB0834.4080101@o2.pl> <20101110211540.GA7063@angua.secretlab.ca> <20101110224516.GA19567@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20101110224516.GA19567@suse.de> User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1690 Lines: 35 On Wed, Nov 10, 2010 at 02:45:16PM -0800, Greg KH wrote: > On Wed, Nov 10, 2010 at 02:15:40PM -0700, Grant Likely wrote: > > On Wed, Nov 10, 2010 at 10:07:05PM +0100, Thomas Gleixner wrote: > > > > I understand that it could be simplified by removing redundant code > > > > (as Grant Likely had suggested before), and moving it to completion > > > > interface instead of manipulating a task structure directly, but > > > > this doesn't mean that the whole GPIO code has to be rewritten just > > > > to add one functionality. > > > > > > It's not about rewriting, it's about fixing the problem in the right > > > way and not just hacking around it. > > > > > > If we see a shortcoming like this, we fix it and do not magically work > > > around it. > > > > +1 > > > > Thomas is right. kobject reference counting is the correct solution. > > Nack on this approach. > > Only use a kobject if you want to be in the sysfs hierarchy (which I > don't think you want to do here.) If you want proper reference > counting, use a 'struct kref' instead. > This is actually an interesting problem. The gpiolib code presently has its own hand-rolled sysfs support, which is entirely optional. If someone is going to go through and do some refactoring anyways it would be worthwile to see how much tidying up using a kobject would permit. kobject-based refcounting could in effect be used like kref-refcounting with the sysfs interface disabled, too. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/