X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=src%2Fstdio%2F__lockfile.c;h=0dcb2a426af86b09fa18bf7b1de3be2775999589;hb=37cd1676395e5ebdae3f372bf59d4fef54be9818;hp=6ebf6202bf189284b8d9a02d153259842a29a0cc;hpb=dba68bf98fc708cea4c478278c889fc7ad802b00;p=musl

diff --git a/src/stdio/__lockfile.c b/src/stdio/__lockfile.c
index 6ebf6202..0dcb2a42 100644
--- a/src/stdio/__lockfile.c
+++ b/src/stdio/__lockfile.c
@@ -1,18 +1,25 @@
 #include "stdio_impl.h"
 #include "pthread_impl.h"
 
+#define MAYBE_WAITERS 0x40000000
+
 int __lockfile(FILE *f)
 {
-	int owner, tid = __pthread_self()->tid;
-	if (f->lock == tid)
+	int owner = f->lock, tid = __pthread_self()->tid;
+	if ((owner & ~MAYBE_WAITERS) == tid)
 		return 0;
-	while ((owner = a_cas(&f->lock, 0, tid)))
-		__wait(&f->lock, &f->waiters, owner, 1);
-	return f->lockcount = 1;
+	owner = a_cas(&f->lock, 0, tid);
+	if (!owner) return 1;
+	while ((owner = a_cas(&f->lock, 0, tid|MAYBE_WAITERS))) {
+		if ((owner & MAYBE_WAITERS) ||
+		    a_cas(&f->lock, owner, owner|MAYBE_WAITERS)==owner)
+			__futexwait(&f->lock, owner|MAYBE_WAITERS, 1);
+	}
+	return 1;
 }
 
 void __unlockfile(FILE *f)
 {
-	a_store(&f->lock, 0);
-	if (f->waiters) __wake(&f->lock, 1, 1);
+	if (a_swap(&f->lock, 0) & MAYBE_WAITERS)
+		__wake(&f->lock, 1, 1);
 }