diff --git a/include/net/ndisc.h b/include/net/ndisc.h
index ec48f42..745bf74 100644
--- a/include/net/ndisc.h
+++ b/include/net/ndisc.h
@@ -127,13 +127,19 @@
 	}
 }
 
+static inline int ndisc_opt_addr_space(struct net_device *dev)
+{
+	return NDISC_OPT_SPACE(dev->addr_len +
+			       ndisc_addr_option_pad(dev->type));
+}
+
 static inline u8 *ndisc_opt_addr_data(struct nd_opt_hdr *p,
 				      struct net_device *dev)
 {
 	u8 *lladdr = (u8 *)(p + 1);
 	int lladdrlen = p->nd_opt_len << 3;
 	int prepad = ndisc_addr_option_pad(dev->type);
-	if (lladdrlen != NDISC_OPT_SPACE(dev->addr_len + prepad))
+	if (lladdrlen != ndisc_opt_addr_space(dev))
 		return NULL;
 	return lladdr + prepad;
 }