cmd_hash
int cmd_hash(int ac, const char **av);
ecode = cmd_hash(ac - 1, (const char **)(void *)&av[1]);
hash_init(engine->cmd_hash);
hash_add(engine->cmd_hash, &desc_node->node,
hash_for_each_safe(engine->cmd_hash, i, tmp, desc_node, node) {
hash_for_each_possible(engine->cmd_hash, desc_node, node,
DECLARE_HASHTABLE(cmd_hash, I915_CMD_HASH_ORDER);