[NET]: Add rtnl_lock_interruptible()

Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/rtnetlink.h

@@ -805,6 +805,7 @@ extern struct semaphore rtnl_sem;
 		        } while(0)
 
 extern void rtnl_lock(void);
+extern int rtnl_lock_interruptible(void);
 extern void rtnl_unlock(void);
 extern void rtnetlink_init(void);
 

net/core/rtnetlink.c

@@ -58,6 +58,11 @@ void rtnl_lock(void)
 	rtnl_shlock();
 }
 
+int rtnl_lock_interruptible(void)
+{
+	return down_interruptible(&rtnl_sem);
+}
+ 
 void rtnl_unlock(void)
 {
 	rtnl_shunlock();
@@ -695,5 +700,6 @@ EXPORT_SYMBOL(rtnetlink_links);
 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);