add rtnl_lock_interruptible()

@@ -806,6 +806,7 @@
 		        } while(0)
 
 extern void rtnl_lock(void);
+extern int rtnl_lock_interruptible(void);
 extern void rtnl_unlock(void);
 extern void rtnetlink_init(void);
 

@@ -57,6 +57,11 @@
 {
 	rtnl_shlock();
 }
+
+int rtnl_lock_interruptible(void)
+{
+	return down_interruptible(&rtnl_sem);
+}
  
 void rtnl_unlock(void)
 {

@@ -696,5 +701,6 @@
 EXPORT_SYMBOL(rtnetlink_put_metrics);
 EXPORT_SYMBOL(rtnl);
 EXPORT_SYMBOL(rtnl_lock);
+EXPORT_SYMBOL(rtnl_lock_interruptible);
 EXPORT_SYMBOL(rtnl_sem);
 EXPORT_SYMBOL(rtnl_unlock);