    OVS_REQUIRES(ct->ct_lock)
{
    uint32_t hash = zone_key_hash(zone, ct->hash_basis);
    struct zone_limit *zl;
    HMAP_FOR_EACH_IN_BUCKET (zl, node, hash, &ct->zone_limits) {
        if (zl->czl.zone == zone) {
            return zl;
        }
    }
    return NULL;
}
    OVS_REQUIRES(ct->ct_lock)
{
    uint32_t hash = zone_key_hash(zone, ct->hash_basis);
    struct zone_limit *zl;
    HMAP_FOR_EACH_IN_BUCKET (zl, node, hash, &ct->zone_limits) {
        if (zl->czl.zone == zone) {
            return zl;
        }
    }
    return NULL;
}