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>

13 files changed, 39 insertions, 31 deletions

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index a3fb57fde623..b11e6e19e96c 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -246,11 +246,16 @@ struct hh_cache
  *
  * We could use other alignment values, but we must maintain the
  * relationship HH alignment <= LL alignment.
+ *
+ * LL_ALLOCATED_SPACE also takes into account the tailroom the device
+ * may need.
  */
 #define LL_RESERVED_SPACE(dev) \
-        (((dev)->hard_header_len&~(HH_DATA_MOD - 1)) + HH_DATA_MOD)
+        ((((dev)->hard_header_len+(dev)->needed_headroom)&~(HH_DATA_MOD - 1)) + HH_DATA_MOD)
 #define LL_RESERVED_SPACE_EXTRA(dev,extra) \
-        ((((dev)->hard_header_len+extra)&~(HH_DATA_MOD - 1)) + HH_DATA_MOD)
+        ((((dev)->hard_header_len+(dev)->needed_headroom+(extra))&~(HH_DATA_MOD - 1)) + HH_DATA_MOD)
+#define LL_ALLOCATED_SPACE(dev) \
+        ((((dev)->hard_header_len+(dev)->needed_headroom+(dev)->needed_tailroom)&~(HH_DATA_MOD - 1)) + HH_DATA_MOD)
 
 struct header_ops {
         int     (*create) (struct sk_buff *skb, struct net_device *dev,
@@ -569,6 +574,13 @@ struct net_device
         unsigned short          type;   /* interface hardware type      */
         unsigned short          hard_header_len;        /* hardware hdr length  */
 
+        /* extra head- and tailroom the hardware may need, but not in all cases
+         * can this be guaranteed, especially tailroom. Some cases also use
+         * LL_MAX_HEADER instead to allocate the skb.
+         */
+        unsigned short          needed_headroom;
+        unsigned short          needed_tailroom;
+
         struct net_device       *master; /* Pointer to master device of a group,
                                           * which this device is member of.
                                           */
diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index b04d643fc3c7..8fb134da0346 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -419,7 +419,7 @@ static void arp_reply(struct sk_buff *skb)
                 return;
 
         size = arp_hdr_len(skb->dev);
-        send_skb = find_skb(np, size + LL_RESERVED_SPACE(np->dev),
+        send_skb = find_skb(np, size + LL_ALLOCATED_SPACE(np->dev),
                             LL_RESERVED_SPACE(np->dev));
 
         if (!send_skb)
diff --git a/net/econet/af_econet.c b/net/econet/af_econet.c
index 68d154480043..7c9bb13b1539 100644
--- a/net/econet/af_econet.c
+++ b/net/econet/af_econet.c
@@ -340,7 +340,7 @@ static int econet_sendmsg(struct kiocb *iocb, struct socket *sock,
 
                 dev_hold(dev);
 
-                skb = sock_alloc_send_skb(sk, len+LL_RESERVED_SPACE(dev),
+                skb = sock_alloc_send_skb(sk, len+LL_ALLOCATED_SPACE(dev),
                                           msg->msg_flags & MSG_DONTWAIT, &err);
                 if (skb==NULL)
                         goto out_unlock;
diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c
index 68b72a7a1806..418862f1bf22 100644
--- a/net/ipv4/arp.c
+++ b/net/ipv4/arp.c
@@ -570,7 +570,7 @@ struct sk_buff *arp_create(int type, int ptype, __be32 dest_ip,
          *      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 6250f4239b61..2769dc4a4c84 100644
--- a/net/ipv4/igmp.c
+++ b/net/ipv4/igmp.c
@@ -292,7 +292,7 @@ static struct sk_buff *igmpv3_newpack(struct net_device *dev, int size)
         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 @@ static int igmp_send_report(struct in_device *in_dev, struct ip_mc_list *pmc,
                 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 89dee4346f60..ed45037ce9be 100644
--- a/net/ipv4/ipconfig.c
+++ b/net/ipv4/ipconfig.c
@@ -710,14 +710,14 @@ static void __init ic_bootp_send_if(struct ic_device *d, unsigned long jiffies_d
         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 11d7f753a820..fead049daf43 100644
--- a/net/ipv4/raw.c
+++ b/net/ipv4/raw.c
@@ -322,7 +322,6 @@ static int raw_send_hdrinc(struct sock *sk, void *from, size_t length,
                         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 @@ static int raw_send_hdrinc(struct sock *sk, void *from, size_t length,
         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;
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 0af2e055f883..48cdce9c696c 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -780,7 +780,7 @@ slow_path:
                  *      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);
diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c
index 54f91efdae58..fd632dd7f98d 100644
--- a/net/ipv6/mcast.c
+++ b/net/ipv6/mcast.c
@@ -1411,7 +1411,7 @@ static struct sk_buff *mld_newpack(struct net_device *dev, int size)
                      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 @@ static void igmp6_send(struct in6_addr *addr, struct net_device *dev, int type)
         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();
diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index 2c74885f8355..a55fc05b8125 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -479,7 +479,7 @@ static void __ndisc_send(struct net_device *dev,
 
         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 @@ void ndisc_send_redirect(struct sk_buff *skb, struct neighbour *neigh,
 
         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
diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c
index 396f0ea11090..232e0dc45bf5 100644
--- a/net/ipv6/raw.c
+++ b/net/ipv6/raw.c
@@ -609,7 +609,6 @@ static int rawv6_send_hdrinc(struct sock *sk, void *from, int length,
         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 @@ static int rawv6_send_hdrinc(struct sock *sk, void *from, int length,
         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;
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 25070240d4ae..2cee87da4441 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -743,7 +743,7 @@ static int packet_sendmsg(struct kiocb *iocb, struct socket *sock,
         if (len > dev->mtu+reserve)
                 goto out_unlock;
 
-        skb = sock_alloc_send_skb(sk, len + LL_RESERVED_SPACE(dev),
+        skb = sock_alloc_send_skb(sk, len + LL_ALLOCATED_SPACE(dev),
                                 msg->msg_flags & MSG_DONTWAIT, &err);
         if (skb==NULL)
                 goto out_unlock;
diff --git a/net/xfrm/xfrm_output.c b/net/xfrm/xfrm_output.c
index 09cd9c0c2d80..3f964db908a7 100644
--- a/net/xfrm/xfrm_output.c
+++ b/net/xfrm/xfrm_output.c
@@ -25,11 +25,11 @@ static int xfrm_state_check_space(struct xfrm_state *x, struct sk_buff *skb)
         struct dst_entry *dst = skb->dst;
         int nhead = dst->header_len + LL_RESERVED_SPACE(dst->dev)
                 - skb_headroom(skb);
+        int ntail = dst->dev->needed_tailroom - skb_tailroom(skb);
 
-        if (nhead > 0)
-                return pskb_expand_head(skb, nhead, 0, GFP_ATOMIC);
+        if (nhead > 0 || ntail > 0)
+                return pskb_expand_head(skb, nhead, ntail, GFP_ATOMIC);
 
-        /* Check tail too... */
         return 0;
 }