M_IOV
iov = mallocarray(iovcnt, sizeof(*iov), M_IOV, M_WAITOK);
free(iov, M_IOV, iovcnt * sizeof(*iov));
free(iov, M_IOV, iovlen * sizeof(struct iovec));
M_IOV, M_WAITOK);
free(iov, M_IOV, sizeof(struct iovec) * msg.msg_iovlen);
free(iov, M_IOV, iovlen *
M_IOV, M_WAITOK);
free(iov, M_IOV, sizeof(struct iovec) * iovlen);
M_IOV, M_WAITOK);
free(iov, M_IOV, sizeof(struct iovec) * msg.msg_iovlen);
free(iov, M_IOV, iovlen *
M_IOV, M_WAITOK);