On 14.11.2013, at 20.05, Kai Mäkisara (Kolumbus) <[email protected]> wrote:
> > On 14.11.2013, at 16.48, Bodo Stroesser <[email protected]> wrote: > > > Hi, > > > > in st_probe(), st.c I stumbled across what I'd call a minor problem. > > > > So I'd like to suggest the following patch. > > > > Best Regards, > > Bodo > > > > P.S.: Please CC me, I'm not on the list. > > > > --------------------------------------------------------------------- > > > > > > From: Bodo Stroesser <[email protected]> > > Date: Thu, 14 Nov 2013 14:35:00 +0100 > > Subject: [PATCH] sg: fix blk_get_queue usage > > > > 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 <[email protected]> > > > > --- > > > > --- a/drivers/scsi/st.c 2013-11-14 14:10:40.000000000 +0100 > > +++ b/drivers/scsi/st.c 2013-11-14 14:10:57.000000000 +0100 > > @@ -4107,11 +4107,11 @@ > > 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. */ > > With this patch, blk_get_queue() is not called with the correct argument. > Maybe change the call to blk_get_queue(SDp->request_queue) ? > > > if (blk_get_queue(disk->queue)) Yes, thank you. You are obviously right. Below is the revised patch. Sorry for the mistake. Bodo > > goto out_put_disk; > > + disk->queue = SDp->request_queue; > > tpnt->driver = &st_template; > > > > tpnt->device = SDp-- > > To unsubscribe from this list: send the line "unsubscribe linux-scsi" in > > the body of a message to [email protected] > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > ; > > Thanks, > Kai > From: Bodo Stroesser <[email protected]> Date: Thu, 14 Nov 2013 14:35:00 +0100 Subject: [PATCH] sg: fix blk_get_queue usage 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(). Revised patch due to a hint from Kai Makisara. Signed-off-by: Bodo Stroesser <[email protected]> --- --- a/drivers/scsi/st.c 2013-11-14 14:10:40.000000000 +0100 +++ b/drivers/scsi/st.c 2013-11-14 14:10:57.000000000 +0100 @@ -4107,11 +4107,11 @@ 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;
