summaryrefslogtreecommitdiff
path: root/src/thread/pthread_rwlock_unlock.c
blob: 5edca634b785c889db3edcbe31b42cc9ccf3abf0 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
#include "pthread_impl.h"

int pthread_rwlock_unlock(pthread_rwlock_t *rw)
{
	int val, cnt, waiters, new;

	do {
		val = rw->_rw_lock;
		cnt = val & 0x7fffffff;
		waiters = rw->_rw_waiters;
		new = (cnt == 0x7fffffff || cnt == 1) ? 0 : val-1;
	} while (a_cas(&rw->_rw_lock, val, new) != val);

	if (!new && (waiters || val<0))
		__wake(&rw->_rw_lock, 1, 0);

	return 0;
}