[NET]: Wrap netdevice hardware header creation.

Add inline for common usage of hardware header creation, and
fix bug in IPV6 mcast where the assumption about negative return is
an errno. Negative return from hard_header means not enough space
was available,(ie -N bytes).

Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 10 insertions, 2 deletions

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 71cf409ad17e..b33d084712fa 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -800,6 +800,15 @@ extern int		dev_restart(struct net_device *dev);
 extern int              netpoll_trap(void);
 #endif
 
+static inline int dev_hard_header(struct sk_buff *skb, struct net_device *dev,
+                                  unsigned short type,
+                                  void *daddr, void *saddr, unsigned len)
+{
+        if (!dev->hard_header)
+                return 0;
+        return dev->hard_header(skb, dev, type, daddr, saddr, len);
+}
+
 typedef int gifconf_func_t(struct net_device * dev, char __user * bufptr, int len);
 extern int              register_gifconf(unsigned int family, gifconf_func_t * gifconf);
 static inline int unregister_gifconf(unsigned int family)
diff --git a/include/net/dn_route.h b/include/net/dn_route.h
index c10e8e7e59a7..60c9f22d8694 100644
--- a/include/net/dn_route.h
+++ b/include/net/dn_route.h
@@ -100,8 +100,7 @@ static inline void dn_rt_finish_output(struct sk_buff *skb, char *dst, char *src
         if ((dev->type != ARPHRD_ETHER) && (dev->type != ARPHRD_LOOPBACK))
                 dst = NULL;
 
-        if (!dev->hard_header || (dev->hard_header(skb, dev, ETH_P_DNA_RT,
-                        dst, src, skb->len) >= 0))
+        if (dev_hard_header(skb, dev, ETH_P_DNA_RT, dst, src, skb->len) >= 0)
                 dn_rt_send(skb);
         else
                 kfree_skb(skb);