bsd/kern/uipc_mbuf.c

842 		(m)->m_data = (m)->m_dat;				\
4463 	return (m->m_data - m->m_dat);
4478 	return (&m->m_dat[MLEN] - (m->m_data + m->m_len));
4833 		    m->m_data + m->m_len + n->m_len >= &m->m_dat[MLEN]) {
4942 	    n->m_data + len < &n->m_dat[MLEN] && n->m_next) {
4960 	space = &m->m_dat[MLEN] - (m->m_data + m->m_len);
5010 	space = &m->m_dat[MLEN] - (m->m_data + m->m_len);
7182 		    (m->m_data != m->m_dat || m->m_len > 0)) {
7196 			    (uint64_t)VM_KERNEL_ADDRPERM(m->m_dat), m->m_len);
7199 			VERIFY((m->m_flags & M_EXT) || m->m_data == m->m_dat);