- int spins=10000;
- int tid;
-
- if (f->lock < 0) return;
- tid = __pthread_self()->tid;
- if (f->lock == tid) {
- while (f->lockcount == INT_MAX);
- f->lockcount++;
- return;
+ int owner = f->lock, tid = __pthread_self()->tid;
+ if ((owner & ~MAYBE_WAITERS) == tid)
+ return 0;
+ owner = a_cas(&f->lock, 0, tid);
+ if (!owner) return 1;
+ while ((owner = a_cas(&f->lock, 0, tid|MAYBE_WAITERS))) {
+ if ((owner & MAYBE_WAITERS) ||
+ a_cas(&f->lock, owner, owner|MAYBE_WAITERS)==owner)
+ __futexwait(&f->lock, owner|MAYBE_WAITERS, 1);