From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Ewan D. Milne" Subject: Re: [PATCH] st: fix blk_get_queue usage Date: Tue, 01 Aug 2017 12:03:25 -0400 Message-ID: <1501603405.4120.35.camel@localhost.localdomain> References: <1501591374-11229-1-git-send-email-hare@suse.de> Reply-To: emilne@redhat.com Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: Received: from mx1.redhat.com ([209.132.183.28]:44756 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751778AbdHAQD1 (ORCPT ); Tue, 1 Aug 2017 12:03:27 -0400 In-Reply-To: <1501591374-11229-1-git-send-email-hare@suse.de> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Hannes Reinecke Cc: "Martin K. Petersen" , Kai =?ISO-8859-1?Q?M=E4kisara?= , Christoph Hellwig , James Bottomley , linux-scsi@vger.kernel.org, Bodo Stroesser , Hannes Reinecke On Tue, 2017-08-01 at 14:42 +0200, Hannes Reinecke wrote: > From: Bodo Stroesser > > If blk_queue_get() in st_probe fails, disk->queue must not > be set to SDp->request_queue, as that would result in > put_disk() dropping a not taken reference. > > Thus, disk->queue should be set only after a successful > blk_queue_get(). > > Signed-off-by: Bodo Stroesser > Acked-by: Shirish Pargaonkar > Signed-off-by: Hannes Reinecke > --- > drivers/scsi/st.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c > index 1ea34d6..f1bcaf6 100644 > --- a/drivers/scsi/st.c > +++ b/drivers/scsi/st.c > @@ -4300,11 +4300,11 @@ static int st_probe(struct device *dev) > kref_init(&tpnt->kref); > tpnt->disk = disk; > disk->private_data = &tpnt->driver; > - disk->queue = SDp->request_queue; > /* SCSI tape doesn't register this gendisk via add_disk(). Manually > * take queue reference that release_disk() expects. */ > - if (!blk_get_queue(disk->queue)) > + if (!blk_get_queue(SDp->request_queue)) > goto out_put_disk; > + disk->queue = SDp->request_queue; > tpnt->driver = &st_template; > > tpnt->device = SDp; Fixes: 2b5bebccd282 ("st: Take additional queue ref in st_probe") Reviewed-by: Ewan D. Milne