- int nr, *p, w=0;
- while (pthread_rwlock_trywrlock(rw)==EAGAIN) {
- if (!w) a_inc(&rw->__waiters), w++;
- if ((nr=rw->__readers)) p = &rw->__readers;
- else nr=1, p = &rw->__wrlock;
- if (__timedwait(p, nr, CLOCK_REALTIME, at, 0)==ETIMEDOUT) {
- if (w) a_dec(&rw->__waiters);
- return ETIMEDOUT;
- }
+ int r, t;
+ while ((r=pthread_rwlock_trywrlock(rw))==EBUSY) {
+ if (!(r=rw->_rw_lock)) continue;
+ t = r | 0x80000000;
+ a_inc(&rw->_rw_waiters);
+ a_cas(&rw->_rw_lock, r, t);
+ r = __timedwait(&rw->_rw_lock, t, CLOCK_REALTIME, at, 0, 0, 0);
+ a_dec(&rw->_rw_waiters);
+ if (r && r != EINTR) return r;