xref: /aosp_15_r20/external/musl/src/thread/pthread_rwlock_timedrdlock.c (revision c9945492fdd68bbe62686c5b452b4dc1be3f8453)
1*c9945492SAndroid Build Coastguard Worker #include "pthread_impl.h"
2*c9945492SAndroid Build Coastguard Worker 
__pthread_rwlock_timedrdlock(pthread_rwlock_t * restrict rw,const struct timespec * restrict at)3*c9945492SAndroid Build Coastguard Worker int __pthread_rwlock_timedrdlock(pthread_rwlock_t *restrict rw, const struct timespec *restrict at)
4*c9945492SAndroid Build Coastguard Worker {
5*c9945492SAndroid Build Coastguard Worker 	int r, t;
6*c9945492SAndroid Build Coastguard Worker 
7*c9945492SAndroid Build Coastguard Worker 	r = pthread_rwlock_tryrdlock(rw);
8*c9945492SAndroid Build Coastguard Worker 	if (r != EBUSY) return r;
9*c9945492SAndroid Build Coastguard Worker 
10*c9945492SAndroid Build Coastguard Worker 	int spins = 100;
11*c9945492SAndroid Build Coastguard Worker 	while (spins-- && rw->_rw_lock && !rw->_rw_waiters) a_spin();
12*c9945492SAndroid Build Coastguard Worker 
13*c9945492SAndroid Build Coastguard Worker 	while ((r=__pthread_rwlock_tryrdlock(rw))==EBUSY) {
14*c9945492SAndroid Build Coastguard Worker 		if (!(r=rw->_rw_lock) || (r&0x7fffffff)!=0x7fffffff) continue;
15*c9945492SAndroid Build Coastguard Worker 		t = r | 0x80000000;
16*c9945492SAndroid Build Coastguard Worker 		a_inc(&rw->_rw_waiters);
17*c9945492SAndroid Build Coastguard Worker 		a_cas(&rw->_rw_lock, r, t);
18*c9945492SAndroid Build Coastguard Worker 		r = __timedwait(&rw->_rw_lock, t, CLOCK_REALTIME, at, rw->_rw_shared^128);
19*c9945492SAndroid Build Coastguard Worker 		a_dec(&rw->_rw_waiters);
20*c9945492SAndroid Build Coastguard Worker 		if (r && r != EINTR) return r;
21*c9945492SAndroid Build Coastguard Worker 	}
22*c9945492SAndroid Build Coastguard Worker 	return r;
23*c9945492SAndroid Build Coastguard Worker }
24*c9945492SAndroid Build Coastguard Worker 
25*c9945492SAndroid Build Coastguard Worker weak_alias(__pthread_rwlock_timedrdlock, pthread_rwlock_timedrdlock);
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