From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753228Ab1BVOVA (ORCPT ); Tue, 22 Feb 2011 09:21:00 -0500 Received: from mx1.redhat.com ([209.132.183.28]:48096 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752247Ab1BVOU7 (ORCPT ); Tue, 22 Feb 2011 09:20:59 -0500 Date: Tue, 22 Feb 2011 09:20:51 -0500 From: Vivek Goyal To: Sergey Senozhatsky Cc: linux-kernel@vger.kernel.org, jaxboe@fusionio.com, neilb@suse.de, tj@kernel.org, jmoyer@redhat.com, snitzer@redhat.com Subject: Re: [PATCH 2/3] loop: No need to initialize ->queue_lock explicitly before calling blk_cleanup_queue() Message-ID: <20110222142050.GB28269@redhat.com> References: <1298346817-26144-1-git-send-email-vgoyal@redhat.com> <1298346817-26144-3-git-send-email-vgoyal@redhat.com> <20110222073032.GA4555@swordfish.minsk.epam.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110222073032.GA4555@swordfish.minsk.epam.com> 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 On Tue, Feb 22, 2011 at 09:30:32AM +0200, Sergey Senozhatsky wrote: > On (02/21/11 22:53), Vivek Goyal wrote: > > o Now we initialize ->queue_lock at queue allocation time so driver does > > not have to worry about initializing it before calling blk_cleanup_queue(). > > > > Signed-off-by: Vivek Goyal > > --- > > drivers/block/loop.c | 3 --- > > 1 files changed, 0 insertions(+), 3 deletions(-) > > > > diff --git a/drivers/block/loop.c b/drivers/block/loop.c > > index 49e6a54..44e18c0 100644 > > --- a/drivers/block/loop.c > > +++ b/drivers/block/loop.c > > @@ -1641,9 +1641,6 @@ out: > > > > static void loop_free(struct loop_device *lo) > > { > > - if (!lo->lo_queue->queue_lock) > > - lo->lo_queue->queue_lock = &lo->lo_queue->__queue_lock; > > - > > blk_cleanup_queue(lo->lo_queue); > > put_disk(lo->lo_disk); > > list_del(&lo->lo_list); > > Hi, > > (just for note) > There is an incremental patch fixing this case in Andrew's mm tree: > https://lkml.org/lkml/2011/2/11/165 > > (block-fix-queue_lock-null-pointer-derefence-in-blk_throtl_exit-v4.patch > added to -mm tree). Hi Sergey, Thinking more about it, initializing queue lock in blk_alloc_queue() seems to be even more cleaner to me instead of initializing it to internal lock during blk_cleanup_queue(). If others like the idea, then we can either ask Andrew to drop the patch or I can generate one on top of it. Thanks Vivek