CHAIN_SZ
err = fence_chains_init(&data.fc, CHAIN_SZ, seqno_inc);
err = fence_chains_init(&fc, CHAIN_SZ, seqno_inc);
err = fence_chains_init(&fc, CHAIN_SZ, seqno_inc);
err = fence_chains_init(&fc, CHAIN_SZ, seqno_inc);