Re: [PATCH 1/3] block: introduce device_add_disk()

[Dan Williams]

On Thu, Mar 10, 2016 at 12:09 AM, Christoph Hellwig <hch@xxxxxx> wrote:
>>  /**
>> - * add_disk - add partitioning information to kernel list
>> + * device_add_disk - add partitioning information to kernel list
>> + * @parent: parent device for the disk
>>   * @disk: per-device partitioning information
>>   *
>>   * This function registers the partitioning information in @disk
>> @@ -581,7 +582,7 @@ exit:
>>   *
>>   * FIXME: error handling
>>   */
>> -void add_disk(struct gendisk *disk)
>> +int device_add_disk(struct device *parent, struct gendisk *disk)
>>  {
>>       struct backing_dev_info *bdi;
>>       dev_t devt;
>> @@ -597,10 +598,8 @@ void add_disk(struct gendisk *disk)
>>       disk->flags |= GENHD_FL_UP;
>>
>>       retval = blk_alloc_devt(&disk->part0, &devt);
>> -     if (retval) {
>> -             WARN_ON(1);
>> -             return;
>> -     }
>> +     if (retval)
>> +             return retval;
>>       disk_to_dev(disk)->devt = devt;
>>
>>       /* ->major and ->first_minor aren't supposed to be
>> @@ -617,7 +616,7 @@ void add_disk(struct gendisk *disk)
>>
>>       blk_register_region(disk_devt(disk), disk->minors, NULL,
>>                           exact_match, exact_lock, disk);
>> -     register_disk(disk);
>> +     register_disk(parent, disk);
>>       blk_register_queue(disk);
>>
>>       /*
>> @@ -628,12 +627,11 @@ void add_disk(struct gendisk *disk)
>>
>>       retval = sysfs_create_link(&disk_to_dev(disk)->kobj, &bdi->dev->kobj,
>>                                  "bdi");
>> -     WARN_ON(retval);
>> -
>>       disk_add_events(disk);
>>       blk_integrity_add(disk);
>> +     return retval;
>
> How are the callers expected to unwind after already having added the
> disk?

True, I overlooked making add_disk() unwind-able, will re-spin...