sysfs_remove_group(&chp->dev.kobj, &chp_attr_group);
device_unregister(&chp->dev);
mutex_unlock(&channel_subsystems[chpid.cssid]->mutex);
sysfs_remove_group(&chp->dev.kobj, &chp_attr_group);
device_unregister(&chp->dev);
mutex_unlock(&channel_subsystems[chpid.cssid]->mutex);