From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753421Ab3IWUOS (ORCPT ); Mon, 23 Sep 2013 16:14:18 -0400 Received: from mail-vc0-f176.google.com ([209.85.220.176]:56537 "EHLO mail-vc0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752936Ab3IWUOR (ORCPT ); Mon, 23 Sep 2013 16:14:17 -0400 Date: Mon, 23 Sep 2013 16:14:12 -0400 From: Tejun Heo To: Tomoki Sekiyama Cc: "linux-kernel@vger.kernel.org" , "axboe@kernel.dk" , Seiji Aguchi , "vgoyal@redhat.com" , "majianpeng@gmail.com" Subject: Re: [PATCH v2 1/2] elevator: Fix a race in elevator switching and md device initialization Message-ID: <20130923201412.GA28667@mtj.dyndns.org> References: <20130922170417.GF30946@htj.dyndns.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, On Mon, Sep 23, 2013 at 08:11:55PM +0000, Tomoki Sekiyama wrote: > >Hmm... why aren't we just changing elevator_init() to grab sysfs_lock > >where necessary? > > The locking cannot be moved into elevator_init() because it is called > from elevator_switch() path, where the request_queue's sysfs_lock is > already taken. > > > It'd be more consistent with elevator_exit() that way. > > What elevator_exit() locks is elevator_queue's sysfs_lock, not > request_queue's sysfs_lock. What we need here is request_queue's > sysfs_lock. Ah, okay. Reviewed-by: Tejun Heo Thanks. -- tejun