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>

net/ipv6/ip6_output.c

diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 0af2e055..48cdce9 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -780,7 +780,7 @@
 		 *	Allocate buffer.
 		 */
 
-		if ((frag = alloc_skb(len+hlen+sizeof(struct frag_hdr)+LL_RESERVED_SPACE(rt->u.dst.dev), GFP_ATOMIC)) == NULL) {
+		if ((frag = alloc_skb(len+hlen+sizeof(struct frag_hdr)+LL_ALLOCATED_SPACE(rt->u.dst.dev), GFP_ATOMIC)) == NULL) {
 			NETDEBUG(KERN_INFO "IPv6: frag: no memory for new fragment!\n");
 			IP6_INC_STATS(ip6_dst_idev(skb->dst),
 				      IPSTATS_MIB_FRAGFAILS);

net/ipv6/mcast.c

diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c
index 54f91ef..fd632dd 100644
--- a/net/ipv6/mcast.c
+++ b/net/ipv6/mcast.c
@@ -1411,7 +1411,7 @@
 		     IPV6_TLV_PADN, 0 };
 
 	/* we assume size > sizeof(ra) here */
-	skb = sock_alloc_send_skb(sk, size + LL_RESERVED_SPACE(dev), 1, &err);
+	skb = sock_alloc_send_skb(sk, size + LL_ALLOCATED_SPACE(dev), 1, &err);
 
 	if (!skb)
 		return NULL;
@@ -1790,7 +1790,7 @@
 	payload_len = len + sizeof(ra);
 	full_len = sizeof(struct ipv6hdr) + payload_len;
 
-	skb = sock_alloc_send_skb(sk, LL_RESERVED_SPACE(dev) + full_len, 1, &err);
+	skb = sock_alloc_send_skb(sk, LL_ALLOCATED_SPACE(dev) + full_len, 1, &err);
 
 	if (skb == NULL) {
 		rcu_read_lock();

net/ipv6/ndisc.c

diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index 2c74885..a55fc05b 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -479,7 +479,7 @@
 
 	skb = sock_alloc_send_skb(sk,
 				  (MAX_HEADER + sizeof(struct ipv6hdr) +
-				   len + LL_RESERVED_SPACE(dev)),
+				   len + LL_ALLOCATED_SPACE(dev)),
 				  1, &err);
 	if (!skb) {
 		ND_PRINTK0(KERN_ERR
@@ -1521,7 +1521,7 @@
 
 	buff = sock_alloc_send_skb(sk,
 				   (MAX_HEADER + sizeof(struct ipv6hdr) +
-				    len + LL_RESERVED_SPACE(dev)),
+				    len + LL_ALLOCATED_SPACE(dev)),
 				   1, &err);
 	if (buff == NULL) {
 		ND_PRINTK0(KERN_ERR

net/ipv6/raw.c

diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c
index 396f0ea..232e0dc 100644
--- a/net/ipv6/raw.c
+++ b/net/ipv6/raw.c
@@ -609,7 +609,6 @@
 	struct ipv6_pinfo *np = inet6_sk(sk);
 	struct ipv6hdr *iph;
 	struct sk_buff *skb;
-	unsigned int hh_len;
 	int err;
 
 	if (length > rt->u.dst.dev->mtu) {
@@ -619,13 +618,12 @@
 	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;