From 056f707c8618062023a79fdbc6ec19ac482c63dd Mon Sep 17 00:00:00 2001
From: Ulrich Drepper <drepper@redhat.com>
Date: Wed, 19 Jul 2000 06:24:30 +0000
Subject: Update.

	* spinlock.h (__pthread_alt_trylock): Fix code used if no
	compare&swap is available.
---
 linuxthreads/spinlock.h | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

(limited to 'linuxthreads/spinlock.h')

diff --git a/linuxthreads/spinlock.h b/linuxthreads/spinlock.h
index 17efd18..703b72d 100644
--- a/linuxthreads/spinlock.h
+++ b/linuxthreads/spinlock.h
@@ -149,7 +149,19 @@ static inline int __pthread_alt_trylock (struct _pthread_fastlock * lock)
 #endif
 #if !defined HAS_COMPARE_AND_SWAP || defined TEST_FOR_COMPARE_AND_SWAP
   {
-    return (testandset(&lock->__spinlock) ? EBUSY : 0);
+    int res = EBUSY;
+
+    if (testandset(&lock->__spinlock) == 0)
+      {
+	if (lock->__status == 0)
+	  {
+	    lock->__status = 1;
+	    WRITE_MEMORY_BARRIER();
+	    res = 0;
+	  }
+	lock->__spinlock = 0;
+      }
+    return res;
   }
 #endif
 
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