From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Subject: Re: [PATCH 1/3][-mm] add class_reclassify macro Date: Tue, 20 May 2008 10:30:45 -0700 Message-ID: <20080520103045.2bb0a033.akpm@linux-foundation.org> References: <20080520095553.GA3201@darkstar.te-china.tietoenator.com> <20080520030232.fc91b64e.akpm@linux-foundation.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: Received: from smtp1.linux-foundation.org ([140.211.169.13]:41933 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756780AbYETRat (ORCPT ); Tue, 20 May 2008 13:30:49 -0400 In-Reply-To: Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Dave Young Cc: greg@kroah.com, matthew@wil.cx, kay.sievers@vrfy.org, linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org On Tue, 20 May 2008 19:05:21 +0800 "Dave Young" wrote: > On Tue, May 20, 2008 at 6:02 PM, Andrew Morton > wrote: > > On Tue, 20 May 2008 17:55:54 +0800 Dave Young wrote: > > > >> Converting class semaphore to mutex cause lockdep warnings due to > >> class_interface_register/unregister will possible call device_add/del > > > > Shouldn't we just fix that? > > Andrew, could you tell more? Well what are these lockdep warnings? Normally such a warning means that we have a locking bug. I _assume_ that you've determined that the warnings are false-positives? The warning which Mariusz Kozlowski discovered ("Subject: Re: 2.6.26-rc2-mm1: possible circular locking dependency detected") was triggered by the "class semaphore to mutex" conversion and it looks like a real bug to me. Would your patch prevent warnings such as that one from being available to us?