Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758567AbYARJIC (ORCPT ); Fri, 18 Jan 2008 04:08:02 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753141AbYARJHp (ORCPT ); Fri, 18 Jan 2008 04:07:45 -0500 Received: from hs-out-0708.google.com ([64.233.178.243]:11097 "EHLO hs-out-2122.google.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1758185AbYARJHl (ORCPT ); Fri, 18 Jan 2008 04:07:41 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=IMf1T3ZEHoPxOvl/R80f4ABclaHWtob49y1mHRaJU6/68jDaFIRGdW8p79Cve4uEZAt+iN21j4dHejTKzObjFp1fR6P0mmlsmZKYWEKkx53ZO7OAGAy55CHt+qlLtT4LNC4hFLPeTHsqmxFjk+C0rBEofBQeQHBUXuEyTZBkcTA= Message-ID: Date: Fri, 18 Jan 2008 17:07:40 +0800 From: "Dave Young" To: "Jarek Poplawski" Subject: Re: [PATCH 7/7] driver-core : convert semaphore to mutex in struct class Cc: "Kay Sievers" , "Alan Stern" , "Greg KH" , stefanr@s5r6.in-berlin.de, "David Brownell" , "Kernel development list" In-Reply-To: <20080118082327.GC1703@ff.dom.local> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <20080117232626.GC2905@ami.dom.local> <3ae72650801171755k85c4245i3b4c46a84ae8f52d@mail.gmail.com> <1200626323.5640.21.camel@lov.site> <20080118073836.GA1703@ff.dom.local> <20080118082327.GC1703@ff.dom.local> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2008 Lines: 54 On Jan 18, 2008 4:23 PM, Jarek Poplawski wrote: > On Fri, Jan 18, 2008 at 03:48:02PM +0800, Dave Young wrote: > > On Jan 18, 2008 3:38 PM, Jarek Poplawski wrote: > ... > > > IMHO, it would be nice to get the real state of current lockdep > > > problems here to figure out if there is any chance to do this right & > > > without any warnings with current lockdep. If I got it right from > > > earlier threads it might be impossible with USB, at least. > > > > I don't think so, usb doesn't be affected by struct class mutex, they > > only use the lock of struct device. As I replied before, the lockdep > > issue exist only between class_interface and class_device. > > OK, but I've meant possibility of changing their own semaphores later. > > > > So, since I think these nesting levels seem to be wrong in 7/7 patch, > > > maybe it's better to exclude it from this patchset, and to try this as > > > testing for some time. > > > > I may file the updated patch with more nesting changes and test it of > > course. Actually I should have done it, thanks. > ... > > 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. > > If SINGLE_LEVEL_NESTING is enough? (means 2 levels total) I think so. > > I think you should more care about real (logical) relations here, than > what's enough to get rid of lockdep warnings. You are quite right, thanks. > > Since there are not so much of these changes, you can try both > variants. Will do. >I'll be glad to look at this - maybe I'll mangage to figure > out BTW, what it's all about... > > 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/