X-Git-Url: http://nsz.repo.hu/git/?p=musl;a=blobdiff_plain;f=src%2Fthread%2Fsem_post.c;h=148ab780e8f94d04ac2a0e222ff1f8631096708a;hp=0bd8a4621116bba5f49c9e70478ce856adb88239;hb=88c4e720317845a8e01aee03f142ba82674cd23d;hpb=6fc5fdbdc70dd17ea8e681a361fb4dae541ee953

diff --git a/src/thread/sem_post.c b/src/thread/sem_post.c
index 0bd8a462..148ab780 100644
--- a/src/thread/sem_post.c
+++ b/src/thread/sem_post.c
@@ -3,7 +3,11 @@
 
 int sem_post(sem_t *sem)
 {
-	if (!a_fetch_add(sem->__val, 1))
-		__wake(sem->__val, 1, 0);
+	int val, waiters;
+	do {
+		val = sem->__val[0];
+		waiters = sem->__val[1];
+	} while (a_cas(sem->__val, val, val+1+(val<0)) != val);
+	if (val<0 || waiters) __wake(sem->__val, 1, 0);
 	return 0;
 }