[PATCH 02/15] genhd: Return error from register_disk()

[Fam Zheng]

Several operations in register_disk can fail, but the caller currently
cannot check for error due to missing return code. Change the function
return type and return -errno if any error happens.

Also add some documentation.

Signed-off-by: Fam Zheng <f...@redhat.com>
---
 block/genhd.c | 27 +++++++++++++++++++++------
 1 file changed, 21 insertions(+), 6 deletions(-)

diff --git a/block/genhd.c b/block/genhd.c
index fcd6d4f..3dcecaa 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -506,7 +506,15 @@ static int exact_lock(dev_t devt, void *data)
        return 0;
 }
 
-static void register_disk(struct device *parent, struct gendisk *disk)
+/**
+ * register_disk - register a gendisk to a parent device
+ * @parent: parent device for the disk
+ * @disk: per-device partitioning information
+ *
+ * RETURNS:
+ * 0 on success, -errno on failure.
+ */
+static int register_disk(struct device *parent, struct gendisk *disk)
 {
        struct device *ddev = disk_to_dev(disk);
        struct block_device *bdev;
@@ -521,14 +529,16 @@ static void register_disk(struct device *parent, struct 
gendisk *disk)
        /* delay uevents, until we scanned partition table */
        dev_set_uevent_suppress(ddev, 1);
 
-       if (device_add(ddev))
-               return;
+       err = device_add(ddev);
+       if (err)
+               return err;
+
        if (!sysfs_deprecated) {
                err = sysfs_create_link(block_depr, &ddev->kobj,
                                        kobject_name(&ddev->kobj));
                if (err) {
                        device_del(ddev);
-                       return;
+                       return err;
                }
        }
 
@@ -547,12 +557,16 @@ static void register_disk(struct device *parent, struct 
gendisk *disk)
                goto exit;
 
        /* No such device (e.g., media were just removed) */
-       if (!get_capacity(disk))
+       if (!get_capacity(disk)) {
+               err = -ENOMEDIUM;
                goto exit;
+       }
 
        bdev = bdget_disk(disk, 0);
-       if (!bdev)
+       if (!bdev) {
+               err = -ENOMEDIUM;
                goto exit;
+       }
 
        bdev->bd_invalidated = 1;
        err = blkdev_get(bdev, FMODE_READ, NULL);
@@ -570,6 +584,7 @@ exit:
        while ((part = disk_part_iter_next(&piter)))
                kobject_uevent(&part_to_dev(part)->kobj, KOBJ_ADD);
        disk_part_iter_exit(&piter);
+       return err;
 }
 
 /**
-- 
2.7.4