block: call bdput() to avoid memleak

hulk inclusion
category: bugfix
bugzilla: 109288
CVE: NA

-------------------------------------------------

bdget_disk() will get bd_inode, so it need to do bdput().

Fixes: 3ad15d050daa ("block: take bd_mutex around delete_partitions in del_gendisk")
Signed-off-by: NYufen Yu <yuyufen@huawei.com>
Reviewed-by: NHou Tao <houtao1@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

block/genhd.c

@@ -783,8 +783,10 @@ void del_gendisk(struct gendisk *disk)
 		delete_partition(disk, part->partno);
 	}
 	disk_part_iter_exit(&piter);
-	if (bdev)
+	if (bdev) {
 		mutex_unlock(&bdev->bd_mutex);
+		bdput(bdev);
+	}
 
 	invalidate_partition(disk, 0);
 	bdev_unhash_inode(disk_devt(disk));