block: make add_partition() return pointer to hd_struct

Make add_partition() return pointer to the new hd_struct on success
and ERR_PTR() value on failure.  This change will be used to fix md
autodetection bug.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Neil Brown <neilb@suse.de>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index e439e6aed832..3df7742ce246 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -522,7 +522,9 @@ extern char *disk_name (struct gendisk *hd, int partno, char *buf);
 
 extern int disk_expand_part_tbl(struct gendisk *disk, int target);
 extern int rescan_partitions(struct gendisk *disk, struct block_device *bdev);
-extern int __must_check add_partition(struct gendisk *, int, sector_t, sector_t, int);
+extern struct hd_struct * __must_check add_partition(struct gendisk *disk,
+                                                     int partno, sector_t start,
+                                                     sector_t len, int flags);
 extern void delete_partition(struct gendisk *, int);
 extern void printk_all_partitions(void);