From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Thu, 11 Jan 2018 10:48:20 +0800 From: Ming Lei To: Mike Snitzer Cc: axboe@kernel.dk, Ming Lei , hch@lst.de, Bart.VanAssche@wdc.com, dm-devel@redhat.com, linux-block@vger.kernel.org Subject: Re: [for-4.16 PATCH v3 1/3] block: only bdi_unregister() in del_gendisk() if !GENHD_FL_HIDDEN Message-ID: <20180111024819.GC7290@ming.t460p> References: <20180111021256.37490-1-snitzer@redhat.com> <20180111021256.37490-2-snitzer@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20180111021256.37490-2-snitzer@redhat.com> List-ID: On Wed, Jan 10, 2018 at 09:12:54PM -0500, Mike Snitzer wrote: > device_add_disk() will only call bdi_register_owner() if > !GENHD_FL_HIDDEN, so it follows that del_gendisk() should only call > bdi_unregister() if !GENHD_FL_HIDDEN. > > Found with code inspection. bdi_unregister() won't do any harm if > bdi_register_owner() wasn't used but best to avoid the unnecessary > call to bdi_unregister(). > > Fixes: 8ddcd65325 ("block: introduce GENHD_FL_HIDDEN") > Signed-off-by: Mike Snitzer > --- > block/genhd.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/block/genhd.c b/block/genhd.c > index 96a66f671720..00620e01e043 100644 > --- a/block/genhd.c > +++ b/block/genhd.c > @@ -725,7 +725,8 @@ void del_gendisk(struct gendisk *disk) > * Unregister bdi before releasing device numbers (as they can > * get reused and we'd get clashes in sysfs). > */ > - bdi_unregister(disk->queue->backing_dev_info); > + if (!(disk->flags & GENHD_FL_HIDDEN)) > + bdi_unregister(disk->queue->backing_dev_info); > blk_unregister_queue(disk); > } else { > WARN_ON(1); > -- > 2.15.0 > Reviewed-by: Ming Lei -- Ming