__tcf_get_next_chain
struct tcf_chain *chain_next = __tcf_get_next_chain(block, chain);
for (chain = __tcf_get_next_chain(block, NULL);
chain = __tcf_get_next_chain(block, chain),
for (chain = __tcf_get_next_chain(block, NULL);
chain = __tcf_get_next_chain(block, chain),