net: Allow netdevices to specify needed head/tailroom

This patch adds needed_headroom/needed_tailroom members to struct
net_device and updates many places that allocate sbks to use them. Not
all of them can be converted though, and I'm sure I missed some (I
mostly grepped for LL_RESERVED_SPACE)

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c
index 68b72a7..418862f 100644
--- a/net/ipv4/arp.c
+++ b/net/ipv4/arp.c
@@ -570,7 +570,7 @@
 	 *	Allocate a buffer
 	 */
 
-	skb = alloc_skb(arp_hdr_len(dev) + LL_RESERVED_SPACE(dev), GFP_ATOMIC);
+	skb = alloc_skb(arp_hdr_len(dev) + LL_ALLOCATED_SPACE(dev), GFP_ATOMIC);
 	if (skb == NULL)
 		return NULL;
 
diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c
index 6250f42..2769dc4 100644
--- a/net/ipv4/igmp.c
+++ b/net/ipv4/igmp.c
@@ -292,7 +292,7 @@
 	struct iphdr *pip;
 	struct igmpv3_report *pig;
 
-	skb = alloc_skb(size + LL_RESERVED_SPACE(dev), GFP_ATOMIC);
+	skb = alloc_skb(size + LL_ALLOCATED_SPACE(dev), GFP_ATOMIC);
 	if (skb == NULL)
 		return NULL;
 
@@ -653,7 +653,7 @@
 		return -1;
 	}
 
-	skb=alloc_skb(IGMP_SIZE+LL_RESERVED_SPACE(dev), GFP_ATOMIC);
+	skb=alloc_skb(IGMP_SIZE+LL_ALLOCATED_SPACE(dev), GFP_ATOMIC);
 	if (skb == NULL) {
 		ip_rt_put(rt);
 		return -1;
diff --git a/net/ipv4/ipconfig.c b/net/ipv4/ipconfig.c
index 89dee43..ed45037 100644
--- a/net/ipv4/ipconfig.c
+++ b/net/ipv4/ipconfig.c
@@ -710,14 +710,14 @@
 	struct net_device *dev = d->dev;
 	struct sk_buff *skb;
 	struct bootp_pkt *b;
-	int hh_len = LL_RESERVED_SPACE(dev);
 	struct iphdr *h;
 
 	/* Allocate packet */
-	skb = alloc_skb(sizeof(struct bootp_pkt) + hh_len + 15, GFP_KERNEL);
+	skb = alloc_skb(sizeof(struct bootp_pkt) + LL_ALLOCATED_SPACE(dev) + 15,
+			GFP_KERNEL);
 	if (!skb)
 		return;
-	skb_reserve(skb, hh_len);
+	skb_reserve(skb, LL_RESERVED_SPACE(dev));
 	b = (struct bootp_pkt *) skb_put(skb, sizeof(struct bootp_pkt));
 	memset(b, 0, sizeof(struct bootp_pkt));
 
diff --git a/net/ipv4/raw.c b/net/ipv4/raw.c
index 11d7f75..fead049 100644
--- a/net/ipv4/raw.c
+++ b/net/ipv4/raw.c
@@ -322,7 +322,6 @@
 			unsigned int flags)
 {
 	struct inet_sock *inet = inet_sk(sk);
-	int hh_len;
 	struct iphdr *iph;
 	struct sk_buff *skb;
 	unsigned int iphlen;
@@ -336,13 +335,12 @@
 	if (flags&MSG_PROBE)
 		goto out;
 
-	hh_len = LL_RESERVED_SPACE(rt->u.dst.dev);
-
-	skb = sock_alloc_send_skb(sk, length+hh_len+15,
-				  flags&MSG_DONTWAIT, &err);
+	skb = sock_alloc_send_skb(sk,
+				  length + LL_ALLOCATED_SPACE(rt->u.dst.dev) + 15,
+				  flags & MSG_DONTWAIT, &err);
 	if (skb == NULL)
 		goto error;
-	skb_reserve(skb, hh_len);
+	skb_reserve(skb, LL_RESERVED_SPACE(rt->u.dst.dev));
 
 	skb->priority = sk->sk_priority;
 	skb->mark = sk->sk_mark;