PV-on-HVM: Add a compatibility linux/mutex.h for kernels before

2.6.16.  This implements the new mutex type in terms of the old
semaphore type.

Signed-off-by: Ian Campbell <ian.campbell@xensource.com>
Signed-off-by: K. Y. Srinivasan <ksrinivasan@novell.com>
Signed-off-by: Tsunehisa Doi <Doi.Tsunehisa@jp.fujitsu.com>

unmodified_drivers/linux-2.6/compat-include/linux/mutex.h

@@ -0,0 +1,31 @@
+/*
+ * Copyright (c) 2006 Cisco Systems.  All rights reserved.
+ *
+ * This file is released under the GPLv2.
+ */
+
+/* mutex compatibility for pre-2.6.16 kernels */
+
+#ifndef __LINUX_MUTEX_H
+#define __LINUX_MUTEX_H
+
+#include <linux/version.h>
+
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16)
+#error "This version of Linux should not need compat mutex.h"
+#endif
+
+#include <linux/version.h>
+#include <asm/semaphore.h>
+
+#define mutex semaphore
+#define DEFINE_MUTEX(foo) DECLARE_MUTEX(foo)
+#define mutex_init(foo) init_MUTEX(foo)
+#define mutex_lock(foo) down(foo)
+#define mutex_lock_interruptible(foo) down_interruptible(foo)
+/* this function follows the spin_trylock() convention, so        *
+ * it is negated to the down_trylock() return values! Be careful  */
+#define mutex_trylock(foo) !down_trylock(foo)
+#define mutex_unlock(foo) up(foo)
+
+#endif /* __LINUX_MUTEX_H */