From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg KH Subject: Re: lockdep whine in 2.6.26-rc2-mm1 Date: Tue, 20 May 2008 11:07:04 -0700 Message-ID: <20080520180704.GA19817@kroah.com> References: <20080514000933.56adc131.akpm@linux-foundation.org> <20080514155639.GB28594@kroah.com> <20080514162442.GO9324@parisc-linux.org> <20080515090101.GA2915@darkstar.te-china.tietoenator.com> <20080515115203.GH9921@parisc-linux.org> <20080519102343.GB2638@parisc-linux.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from pentafluge.infradead.org ([213.146.154.40]:56931 "EHLO pentafluge.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932912AbYETSIP (ORCPT ); Tue, 20 May 2008 14:08:15 -0400 Content-Disposition: inline In-Reply-To: Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Dave Young Cc: Matthew Wilcox , Andrew Morton , linux-scsi@vger.kernel.org, Kay Sievers On Tue, May 20, 2008 at 09:27:59AM +0800, Dave Young wrote: > On Mon, May 19, 2008 at 6:23 PM, Matthew Wilcox wrote: > > On Mon, May 19, 2008 at 01:20:33PM +0800, Dave Young wrote: > >> On Sat, May 17, 2008 at 6:14 PM, Dave Young wrote: > >> > On 5/15/08, Matthew Wilcox wrote: > >> >> On Thu, May 15, 2008 at 05:01:01PM +0800, Dave Young wrote: > >> >>> > The classes are different here, first sdev_class, then sg_sysfs_class > >> >> > >> >> Oh ... right. I misread scsi_register_interface as > >> >> class_register_interface. > >> >> > >> >>> Greg, what about using mutex_lock_nested to silence lockdep? They are > >> >>> the only usage of class->mutex out of class.c > >> >> > >> >> I don't see how we prove that, for example, you can never take the > >> >> sg_sysfs_class mutex and then take the sdev_class mutex. > >> > > >> > Sorry for my delay. AFAIK, there's no this kind of use. > > > > The question isn't whether there is or isn't this kind of use right now. > > The question is whether there might be this kind of use in the future, > > and if there is, whether we'd like lockdep to warn us. > > In the future, IMHO, the class_interface should go away just as > class_device. If that happened this problem would going away as well. Patches gladly accepted to do this, but what you will end up with is something just called a different name, yet doing the same functionality, so you are back at square one :( thanks, greg k-h