1 #include "threads_impl.h"
2
pthread_rwlock_timedrdlock(pthread_rwlock_t * restrict rw,const struct timespec * restrict at)3 int pthread_rwlock_timedrdlock(pthread_rwlock_t* restrict rw, const struct timespec* restrict at) {
4 int r, t;
5
6 r = pthread_rwlock_tryrdlock(rw);
7 if (r != EBUSY)
8 return r;
9
10 int spins = 100;
11 while (spins-- && atomic_load(&rw->_rw_lock) && !atomic_load(&rw->_rw_waiters))
12 a_spin();
13
14 while ((r = pthread_rwlock_tryrdlock(rw)) == EBUSY) {
15 if (!(r = atomic_load(&rw->_rw_lock)) || (r & PTHREAD_MUTEX_OWNED_LOCK_MASK) != PTHREAD_MUTEX_OWNED_LOCK_MASK)
16 continue;
17 t = r | PTHREAD_MUTEX_OWNED_LOCK_BIT;
18 atomic_fetch_add(&rw->_rw_waiters, 1);
19 a_cas_shim(&rw->_rw_lock, r, t);
20 r = __timedwait(&rw->_rw_lock, t, CLOCK_REALTIME, at);
21 atomic_fetch_sub(&rw->_rw_waiters, 1);
22 if (r)
23 return r;
24 }
25 return r;
26 }
27