LOCAL: disk-lights work 2

@@ -835,5 +835,57 @@
         wp->tw_thp = thp;
         wp->tw_mod = mod;
 
         return (wp);
 }
+
+/*
+ * Walk the direct children of the given node.
+ */
+int
+topo_node_child_walk(topo_hdl_t *thp, tnode_t *pnode, topo_walk_cb_t cb_f,
+    void *arg, int *errp)
+{
+        int ret = TOPO_WALK_TERMINATE;
+        tnode_t *cnode;
+
+        topo_node_hold(pnode);
+
+        /*
+         * First Child:
+         */
+        topo_node_lock(pnode);
+        cnode = topo_child_first(pnode);
+        topo_node_unlock(pnode);
+
+        if (cnode == NULL) {
+                *errp = ETOPO_WALK_EMPTY;
+                ret = TOPO_WALK_ERR;
+                goto out;
+        }
+
+        while (cnode != NULL) {
+                int iret;
+
+                /*
+                 * Call the walker callback:
+                 */
+                topo_node_hold(cnode);
+                iret = cb_f(thp, cnode, arg);
+                topo_node_rele(cnode);
+                if (iret != TOPO_WALK_NEXT) {
+                        ret = iret;
+                        break;
+                }
+
+                /*
+                 * Next child:
+                 */
+                topo_node_lock(pnode);
+                cnode = topo_child_next(pnode, cnode);
+                topo_node_unlock(pnode);
+        }
+
+out:
+        topo_node_rele(pnode);
+        return (ret);
+}