From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759239Ab2D0QJJ (ORCPT ); Fri, 27 Apr 2012 12:09:09 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:53266 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752127Ab2D0QJH (ORCPT ); Fri, 27 Apr 2012 12:09:07 -0400 Date: Fri, 27 Apr 2012 09:09:02 -0700 From: Tejun Heo To: Alan Stern Cc: "Eric W. Biederman" , Peter Zijlstra , Kernel development list Subject: Re: Lockdep false positive in sysfs Message-ID: <20120427160902.GO27486@google.com> References: <20120426221753.GF27486@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, On Fri, Apr 27, 2012 at 11:57:02AM -0400, Alan Stern wrote: > By the way, do you know why attribute structures allow for dynamic keys > as well as static keys? I see dynamic keys are used by attribute > containers, but I don't understand why. I have no idea. Eric? > > > Another idea is to have A's method temporarily drop the sysfs readlock. > > > Of course that would put the onus on the USB core of guaranteeing that > > > A cannot be removed while this happens, but we can handle that. > > > > Yeah, that's an easier way out. Please make it a proper sysfs API > > call tho so that people working on sysfs later can know of the special > > case. > > I will. > > Would it be better to release just the lockdep annotation while > continuing to hold the actual lock, or to really drop the lock? Just the lockdep annotation, I think. Thanks. -- tejun