[PATCH 06/15] genhd: Add return code to device_add_disk

Fam Zheng
2016-08-17T07:15:06Z

There are a number of places in device_add_disk that can fail, and even
more to come as we extend it.

Switch the return type of the function, and return the error code when
error happens.

The WARN_ON is kept because callers are not updated to check the error
yet.

Signed-off-by: Fam Zheng <famz@redhat.com>
---
block/genhd.c | 49 ++++++++++++++++++++++++++++++++++---------------
include/linux/genhd.h | 2 +-
2 files changed, 35 insertions(+), 16 deletions(-)

diff --git a/block/genhd.c b/block/genhd.c
index 4316d2d..ffb3929 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -595,9 +595,10 @@ exit:
* This function registers the partitioning information in @disk
* with the kernel.
*
- * FIXME: error handling
+ * RETURNS:
+ * 0 on success, -errno on failure.
*/
-void device_add_disk(struct device *parent, struct gendisk *disk)
+int device_add_disk(struct device *parent, struct gendisk *disk)
{
struct backing_dev_info *bdi;
dev_t devt;
@@ -613,10 +614,8 @@ void device_add_disk(struct device *parent, struct gendisk *disk)
disk->flags |= GENHD_FL_UP;

retval = blk_alloc_devt(&disk->part0, &devt);
- if (retval) {
- WARN_ON(1);
- return;
- }
+ if (retval)
+ goto fail;
disk_to_dev(disk)->devt = devt;

/* ->major and ->first_minor aren't supposed to be
@@ -625,16 +624,26 @@ void device_add_disk(struct device *parent, struct gendisk *disk)
disk->major = MAJOR(devt);
disk->first_minor = MINOR(devt);

- disk_alloc_events(disk);
+ retval = disk_alloc_events(disk);
+ if (retval)
+ goto fail;

/* Register BDI before referencing it from bdev */
bdi = &disk->queue->backing_dev_info;
- bdi_register_owner(bdi, disk_to_dev(disk));
+ retval = bdi_register_owner(bdi, disk_to_dev(disk));
+ if (retval)
+ goto fail;

- blk_register_region(disk_devt(disk), disk->minors, NULL,
- exact_match, exact_lock, disk);
- register_disk(parent, disk);
- blk_register_queue(disk);
+ retval = blk_register_region(disk_devt(disk), disk->minors, NULL,
+ exact_match, exact_lock, disk);
+ if (retval)
+ goto fail;
+ retval = register_disk(parent, disk);
+ if (retval)
+ goto fail;
+ retval = blk_register_queue(disk);
+ if (retval)
+ goto fail;

/*
* Take an extra ref on queue which will be put on disk_release()
@@ -644,10 +653,20 @@ void device_add_disk(struct device *parent, struct gendisk *disk)

retval = sysfs_create_link(&disk_to_dev(disk)->kobj, &bdi->dev->kobj,
"bdi");
+ if (retval)
+ goto fail;
+
+ retval = disk_add_events(disk);
+ if (retval)
+ goto fail;
+
+ retval = blk_integrity_add(disk);
+ if (retval)
+ goto fail;
+ return 0;
+fail:
WARN_ON(retval);
-
- disk_add_events(disk);
- blk_integrity_add(disk);
+ return retval;
}
EXPORT_SYMBOL(device_add_disk);

diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 85ce560..991b5ff 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -413,7 +413,7 @@ static inline void free_part_info(struct hd_struct *part)
extern void part_round_stats(int cpu, struct hd_struct *part);

/* block/genhd.c */
-extern void device_add_disk(struct device *parent, struct gendisk *disk);
+extern int device_add_disk(struct device *parent, struct gendisk *disk);

extern void del_gendisk(struct gendisk *gp);
extern struct gendisk *get_gendisk(dev_t dev, int *partno);
--
2.7.4