[NET]: Move hardware header operations out of netdevice.

Since hardware header operations are part of the protocol class
not the device instance, make them into a separate object and
save memory.

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

3 files changed, 14 insertions, 7 deletions

diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c
index 5b24c65b13c6..d8248198bcd7 100644
--- a/net/ipv4/arp.c
+++ b/net/ipv4/arp.c
@@ -253,7 +253,7 @@ static int arp_constructor(struct neighbour *neigh)
         neigh->parms = neigh_parms_clone(parms);
         rcu_read_unlock();
 
-        if (dev->hard_header == NULL) {
+        if (!dev->header_ops) {
                 neigh->nud_state = NUD_NOARP;
                 neigh->ops = &arp_direct_ops;
                 neigh->output = neigh->ops->queue_xmit;
@@ -310,10 +310,12 @@ static int arp_constructor(struct neighbour *neigh)
                         neigh->nud_state = NUD_NOARP;
                         memcpy(neigh->ha, dev->broadcast, dev->addr_len);
                 }
-                if (dev->hard_header_cache)
+
+                if (dev->header_ops->cache)
                         neigh->ops = &arp_hh_ops;
                 else
                         neigh->ops = &arp_generic_ops;
+
                 if (neigh->nud_state&NUD_VALID)
                         neigh->output = neigh->ops->connected_output;
                 else
diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index ffa9f1c9dcbb..f151900efaf9 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -684,7 +684,7 @@ static int ipgre_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
                 goto tx_error;
         }
 
-        if (dev->hard_header) {
+        if (dev->header_ops) {
                 gre_hlen = 0;
                 tiph = (struct iphdr*)skb->data;
         } else {
@@ -1063,8 +1063,9 @@ static int ipgre_tunnel_change_mtu(struct net_device *dev, int new_mtu)
 
  */
 
-static int ipgre_header(struct sk_buff *skb, struct net_device *dev, unsigned short type,
-                        void *daddr, void *saddr, unsigned len)
+static int ipgre_header(struct sk_buff *skb, struct net_device *dev,
+                        unsigned short type,
+                        const void *daddr, const void *saddr, unsigned len)
 {
         struct ip_tunnel *t = netdev_priv(dev);
         struct iphdr *iph = (struct iphdr *)skb_push(skb, t->hlen);
@@ -1091,6 +1092,10 @@ static int ipgre_header(struct sk_buff *skb, struct net_device *dev, unsigned sh
         return -t->hlen;
 }
 
+static const struct header_ops ipgre_header_ops = {
+        .create = ipgre_header,
+};
+
 static int ipgre_open(struct net_device *dev)
 {
         struct ip_tunnel *t = netdev_priv(dev);
@@ -1187,7 +1192,7 @@ static int ipgre_tunnel_init(struct net_device *dev)
                         if (!iph->saddr)
                                 return -EINVAL;
                         dev->flags = IFF_BROADCAST;
-                        dev->hard_header = ipgre_header;
+                        dev->header_ops = &ipgre_header_ops;
                         dev->open = ipgre_open;
                         dev->stop = ipgre_close;
                 }
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index 77f67b7cb9bf..699f06781fd8 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -169,7 +169,7 @@ static inline int ip_finish_output2(struct sk_buff *skb)
                 IP_INC_STATS(IPSTATS_MIB_OUTBCASTPKTS);
 
         /* Be paranoid, rather than too clever. */
-        if (unlikely(skb_headroom(skb) < hh_len && dev->hard_header)) {
+        if (unlikely(skb_headroom(skb) < hh_len && dev->header_ops)) {
                 struct sk_buff *skb2;
 
                 skb2 = skb_realloc_headroom(skb, LL_RESERVED_SPACE(dev));