M_EXT_ROMAP
m->m_flags |= M_EXT_PAGES | M_EXT_ROMAP;
m->m_flags |= M_EXT_PAGES | M_EXT_ROMAP;
m->m_flags |= M_EXT_ROMAP;
(((m)->m_flags & (M_EXT_ROMAP|M_EXT_RW)) != M_EXT_RW || \
(((m)->m_flags & (M_EXT|M_EXT_ROMAP)) == (M_EXT|M_EXT_ROMAP))