lwp_rwlock_lock
return (lwp_rwlock_lock(rwlp, tsp, READ_LOCK));
return (lwp_rwlock_lock(rwlp, tsp, WRITE_LOCK));
return (lwp_rwlock_lock(rwlp, NULL, READ_LOCK_TRY));
return (lwp_rwlock_lock(rwlp, NULL, WRITE_LOCK_TRY));