xref: /aosp_15_r20/external/musl/src/thread/pthread_rwlock_unlock.c (revision c9945492fdd68bbe62686c5b452b4dc1be3f8453)
1*c9945492SAndroid Build Coastguard Worker #include "pthread_impl.h"
2*c9945492SAndroid Build Coastguard Worker 
__pthread_rwlock_unlock(pthread_rwlock_t * rw)3*c9945492SAndroid Build Coastguard Worker int __pthread_rwlock_unlock(pthread_rwlock_t *rw)
4*c9945492SAndroid Build Coastguard Worker {
5*c9945492SAndroid Build Coastguard Worker 	int val, cnt, waiters, new, priv = rw->_rw_shared^128;
6*c9945492SAndroid Build Coastguard Worker 
7*c9945492SAndroid Build Coastguard Worker 	do {
8*c9945492SAndroid Build Coastguard Worker 		val = rw->_rw_lock;
9*c9945492SAndroid Build Coastguard Worker 		cnt = val & 0x7fffffff;
10*c9945492SAndroid Build Coastguard Worker 		waiters = rw->_rw_waiters;
11*c9945492SAndroid Build Coastguard Worker 		new = (cnt == 0x7fffffff || cnt == 1) ? 0 : val-1;
12*c9945492SAndroid Build Coastguard Worker 	} while (a_cas(&rw->_rw_lock, val, new) != val);
13*c9945492SAndroid Build Coastguard Worker 
14*c9945492SAndroid Build Coastguard Worker 	if (!new && (waiters || val<0))
15*c9945492SAndroid Build Coastguard Worker 		__wake(&rw->_rw_lock, cnt, priv);
16*c9945492SAndroid Build Coastguard Worker 
17*c9945492SAndroid Build Coastguard Worker 	return 0;
18*c9945492SAndroid Build Coastguard Worker }
19*c9945492SAndroid Build Coastguard Worker 
20*c9945492SAndroid Build Coastguard Worker weak_alias(__pthread_rwlock_unlock, pthread_rwlock_unlock);
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