diff -ru4 2.4.1/include/asm-i386/semaphore.h 2.4.1-ben/include/asm-i386/semaphore.h
--- 2.4.1/include/asm-i386/semaphore.h	Fri Feb 16 18:47:23 2001
+++ 2.4.1-ben/include/asm-i386/semaphore.h	Tue Feb 20 14:23:19 2001
@@ -381,6 +381,61 @@
 #endif
 	__up_write(sem);
 }
 
+/* returns 0 if it successfully obtained the semaphore for write */
+static inline int down_write_trylock(struct rw_semaphore *sem)
+{
+	int old = RW_LOCK_BIAS, new = 0;
+
+#if WAITQUEUE_DEBUG
+	if (sem->__magic != (long)&sem->__magic)
+		BUG();
+#endif
+	if (cmpxchg(&sem->count.counter, old, new) == RW_LOCK_BIAS) {
+#if WAITQUEUE_DEBUG
+		if (atomic_read(&sem->writers))
+			BUG();
+		if (atomic_read(&sem->readers))
+			BUG();
+		if (sem->read_bias_granted)
+			BUG();
+		if (sem->write_bias_granted)
+			BUG();
+		atomic_inc(&sem->writers);
+#endif
+		return 0;
+	}
+	else
+		return 1;
+}
+
+/* returns 0 if it successfully obtained the semaphore for read */
+static inline int down_read_trylock(struct rw_semaphore *sem)
+{
+	int old, new;
+
+#if WAITQUEUE_DEBUG
+	if (sem->__magic != (long)&sem->__magic)
+		BUG();
+#endif
+repeat:
+	old = atomic_read(&sem->count);
+	if (old <= 0)
+		return 1;
+	new = old - 1;
+	if (cmpxchg(&sem->count.counter, old, new) == old) {
+#if WAITQUEUE_DEBUG
+		if (sem->write_bias_granted)
+			BUG();
+		if (atomic_read(&sem->writers))
+			BUG();
+		atomic_inc(&sem->readers);
+#endif
+		return 0;
+	}
+	else
+		goto repeat;
+}
+
 #endif
 #endif