Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757292AbYAUBRo (ORCPT ); Sun, 20 Jan 2008 20:17:44 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756272AbYAUBRf (ORCPT ); Sun, 20 Jan 2008 20:17:35 -0500 Received: from fg-out-1718.google.com ([72.14.220.152]:25174 "EHLO fg-out-1718.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756256AbYAUBRf (ORCPT ); Sun, 20 Jan 2008 20:17:35 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:references:mime-version:content-type:content-disposition:in-reply-to:user-agent; b=H9R8OIh4VqA1Jwptn4Q1r/9tOB/JzH71b+KFDfcJVA/oDOkx26TaN5ng4JzxYYDUmHCnYESeyl/01aY09CEzcwYIhFbPQBBDyG5p7FK1T9u3xk62TYpXOxOQ4RZLCgwH8Mp0AKYv0ulFwvKGQ7Ia/rAWCNzYRwQGLgXTdGil0yA= Date: Mon, 21 Jan 2008 09:19:09 +0800 From: Dave Young To: Jarek Poplawski Cc: Kay Sievers , Alan Stern , Greg KH , stefanr@s5r6.in-berlin.de, David Brownell , Kernel development list Subject: Re: [PATCH 7/7] driver-core : convert semaphore to mutex in struct class Message-ID: <20080121011909.GA2832@darkstar.te-china.tietoenator.com> References: <3ae72650801171755k85c4245i3b4c46a84ae8f52d@mail.gmail.com> <1200626323.5640.21.camel@lov.site> <20080118073836.GA1703@ff.dom.local> <20080118082327.GC1703@ff.dom.local> <4791C555.9050205@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4791C555.9050205@gmail.com> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1689 Lines: 42 On Sat, Jan 19, 2008 at 10:39:33AM +0100, Jarek Poplawski wrote: > Dave Young wrote, On 01/18/2008 10:07 AM: > > > On Jan 18, 2008 4:23 PM, Jarek Poplawski wrote: > > >> On Fri, Jan 18, 2008 at 03:48:02PM +0800, Dave Young wrote: > > ... > > >>> 1) Using CLASS_NORMAL/CLASS_PARENT/CLASS_CHILD will be enough. > >>> or > >>> 2) Simply add SINGLE_LEVEL_NESTING in class_device_add and other > >>> class_device functions because it is the only possible nest-lock place > >>> as I know. > > > Dave, after looking a bit at this it seems you could be "mostly" right > with this 2). Maybe I've missed something (I didn't verify this yet), but > it looks like +1 level (SINGLE_LEVEL_NESTING) could be needed in: > class_device_add() (as you did), but probably also class_device_del() and > class_device_destroy(). Yes, I think so too. > > ...But, there seems to be "little" problem, if there is used this recursion > with: class_intf->add()/remove() in class_device_add()/del()?! Then Kay > is right about possibility of deeper nesting. If this path is really used, > and any of these class_device_* functions with locking are called, then > this patch couldn't work like this. So, there is a question: how deep > nesting is currently used here? Currently I couldn't find such use in kernel source. IMO, drivers would not use it like this in the future because class_device will going away soon. > > Regards, > Jarek P. -- 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/