walk_devs
static int walk_devs(dev_info_t *, int (*f)(dev_info_t *, void *), void *, int);
if (walk_devs(ddi_get_child(head->dip), f, arg, do_locking) ==
(void) walk_devs(dip, f, arg, 1);
(void) walk_devs(top_devinfo, reset_leaf_device, NULL, 0);