rumpuser_curlwp
rw->o = rumpuser_curlwp();
*rvp = rw->o == rumpuser_curlwp();
assert(rw->o == rumpuser_curlwp());
rw->o = rumpuser_curlwp();
mtx->owner = rumpuser_curlwp();
return rw->writer == rumpuser_curlwp() && rw->readers == (unsigned)-1;
rw->writer = rumpuser_curlwp();
struct lwp *rumpuser_curlwp(void);
return rumpuser_curlwp();