diff --git a/include/net/ndisc.h b/include/net/ndisc.h
index ec48f42db5ed1fb5f7c4812915ea7c2ce501efd4..745bf741e029c50d8a464374ec5cc4bae855c655 100644
--- a/include/net/ndisc.h
+++ b/include/net/ndisc.h
@@ -127,13 +127,19 @@ static int ndisc_addr_option_pad(unsigned short type)
 	}
 }
 
+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;
 }
diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index 49dfc2a73ee04bbc543d669e1a384a0476d8154c..82ccf0a43063faf8e105e7c2b79dcf1d915bee19 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -143,17 +143,12 @@ struct neigh_table nd_tbl = {
 	.gc_thresh3 =	1024,
 };
 
-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 u8 *ndisc_fill_addr_option(u8 *opt, int type, void *data,
 				  struct net_device *dev)
 {
 	int pad   = ndisc_addr_option_pad(dev->type);
 	int data_len = dev->addr_len;
-	int space = NDISC_OPT_SPACE(data_len + pad);
+	int space = ndisc_opt_addr_space(dev);
 
 	opt[0] = type;
 	opt[1] = space>>3;