RUMPRW
rumpuser_rw_destroy(RUMPRW(rw));
rumpuser_rw_enter(krw2rumprw(op), RUMPRW(rw));
error = rumpuser_rw_tryenter(krw2rumprw(op), RUMPRW(rw));
rumpuser_rw_exit(RUMPRW(rw));
rv = rumpuser_rw_tryupgrade(RUMPRW(rw));
rumpuser_rw_downgrade(RUMPRW(rw));
rumpuser_rw_held(RUMPUSER_RW_READER, RUMPRW(rw), &rv);
rumpuser_rw_held(RUMPUSER_RW_WRITER, RUMPRW(rw), &rv);