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>

3 files changed, 19 insertions, 17 deletions

diff --git a/block/ioctl.c b/block/ioctl.c
index c832d639b6e2..d03985b04d67 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -18,7 +18,6 @@ static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg __user
         struct disk_part_iter piter;
         long long start, length;
         int partno;
-        int err;
 
         if (!capable(CAP_SYS_ADMIN))
                 return -EACCES;
@@ -61,10 +60,10 @@ static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg __user
                         disk_part_iter_exit(&piter);
 
                         /* all seems OK */
-                        err = add_partition(disk, partno, start, length,
-                                            ADDPART_FLAG_NONE);
+                        part = add_partition(disk, partno, start, length,
+                                             ADDPART_FLAG_NONE);
                         mutex_unlock(&bdev->bd_mutex);
-                        return err;
+                        return IS_ERR(part) ? PTR_ERR(part) : 0;
                 case BLKPG_DEL_PARTITION:
                         part = disk_get_part(disk, partno);
                         if (!part)
diff --git a/fs/partitions/check.c b/fs/partitions/check.c
index 90bcf136a9de..633025340239 100644
--- a/fs/partitions/check.c
+++ b/fs/partitions/check.c
@@ -348,8 +348,8 @@ static ssize_t whole_disk_show(struct device *dev,
 static DEVICE_ATTR(whole_disk, S_IRUSR | S_IRGRP | S_IROTH,
                    whole_disk_show, NULL);
 
-int add_partition(struct gendisk *disk, int partno,
-                  sector_t start, sector_t len, int flags)
+struct hd_struct *add_partition(struct gendisk *disk, int partno,
+                                sector_t start, sector_t len, int flags)
 {
         struct hd_struct *p;
         dev_t devt = MKDEV(0, 0);
@@ -361,15 +361,15 @@ int add_partition(struct gendisk *disk, int partno,
 
         err = disk_expand_part_tbl(disk, partno);
         if (err)
-                return err;
+                return ERR_PTR(err);
         ptbl = disk->part_tbl;
 
         if (ptbl->part[partno])
-                return -EBUSY;
+                return ERR_PTR(-EBUSY);
 
         p = kzalloc(sizeof(*p), GFP_KERNEL);
         if (!p)
-                return -ENOMEM;
+                return ERR_PTR(-EBUSY);
 
         if (!init_part_stats(p)) {
                 err = -ENOMEM;
@@ -424,20 +424,20 @@ int add_partition(struct gendisk *disk, int partno,
         if (!ddev->uevent_suppress)
                 kobject_uevent(&pdev->kobj, KOBJ_ADD);
 
-        return 0;
+        return p;
 
 out_free_stats:
         free_part_stats(p);
 out_free:
         kfree(p);
-        return err;
+        return ERR_PTR(err);
 out_del:
         kobject_put(p->holder_dir);
         device_del(pdev);
 out_put:
         put_device(pdev);
         blk_free_devt(devt);
-        return err;
+        return ERR_PTR(err);
 }
 
 /* Not exported, helper to add_disk(). */
@@ -568,10 +568,11 @@ int rescan_partitions(struct gendisk *disk, struct block_device *bdev)
                                disk->disk_name, p, (unsigned long long) size);
                         size = get_capacity(disk) - from;
                 }
-                res = add_partition(disk, p, from, size, state->parts[p].flags);
-                if (res) {
-                        printk(KERN_ERR " %s: p%d could not be added: %d\n",
-                                disk->disk_name, p, -res);
+                part = add_partition(disk, p, from, size,
+                                     state->parts[p].flags);
+                if (IS_ERR(part)) {
+                        printk(KERN_ERR " %s: p%d could not be added: %ld\n",
+                               disk->disk_name, p, -PTR_ERR(part));
                         continue;
                 }
 #ifdef CONFIG_BLK_DEV_MD
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);