nh_rpchc
TAILQ_INIT(&host->nh_rpchc);
TAILQ_INSERT_HEAD(&hostp->nh_rpchc, rpcp, nr_link);
while ((rpcp = TAILQ_FIRST(&hostp->nh_rpchc)) != NULL) {
TAILQ_REMOVE(&hostp->nh_rpchc, rpcp, nr_link);
if (TAILQ_EMPTY(&hostp->nh_rpchc))
TAILQ_FOREACH(rpcp, &hostp->nh_rpchc, nr_link) {
TAILQ_REMOVE(&hostp->nh_rpchc, rpcp, nr_link);