From: weiping zhang <zhangweiping@didichuxing.com>
Date: Tue, 31 Oct 2017 18:38:59 +0800
Subject: [PATCH] block: add WARN_ON if bdi register fail
Git-commit: 3a92168bc8a113098b44a95d499557a88bb387da
Patch-mainline: v4.15-rc2
References: bsc#1104967,FATE#325924

device_add_disk need do more safety error handle, so this patch just
add WARN_ON.

Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: weiping zhang <zhangweiping@didichuxing.com>

Adapted for current series by me.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Hannes Reinecke <hare@suse.com>
---
 block/genhd.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/block/genhd.c b/block/genhd.c
index c2223f12a805..c143a2274238 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -671,10 +671,13 @@ void device_add_disk(struct device *parent, struct gendisk *disk)
 		disk->flags |= GENHD_FL_SUPPRESS_PARTITION_INFO;
 		disk->flags |= GENHD_FL_NO_PART_SCAN;
 	} else {
+		int ret;
+
 		/* Register BDI before referencing it from bdev */
 		disk_to_dev(disk)->devt = devt;
-		bdi_register_owner(disk->queue->backing_dev_info,
-				disk_to_dev(disk));
+		ret = bdi_register_owner(disk->queue->backing_dev_info,
+						disk_to_dev(disk));
+		WARN_ON(ret);
 		blk_register_region(disk_devt(disk), disk->minors, NULL,
 				    exact_match, exact_lock, disk);
 	}
-- 
2.16.4