ipv6: Remove all uses of LL_ALLOCATED_SPACE

ipv6: Remove all uses of LL_ALLOCATED_SPACE

The macro LL_ALLOCATED_SPACE was ill-conceived.  It applies the
alignment to the sum of needed_headroom and needed_tailroom.  As
the amount that is then reserved for head room is needed_headroom
with alignment, this means that the tail room left may be too small.

This patch replaces all uses of LL_ALLOCATED_SPACE in net/ipv6
with the macro LL_RESERVED_SPACE and direct reference to
needed_tailroom.

This also fixes the problem with needed_headroom changing between
allocating the skb and reserving the head room.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 9 insertions, 4 deletions

diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index 4a2098222625..d699ddcad4ce 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -446,6 +446,8 @@ struct sk_buff *ndisc_build_skb(struct net_device *dev,
         struct sock *sk = net->ipv6.ndisc_sk;
         struct sk_buff *skb;
         struct icmp6hdr *hdr;
+        int hlen = LL_RESERVED_SPACE(dev);
+        int tlen = dev->needed_tailroom;
         int len;
         int err;
         u8 *opt;
@@ -459,7 +461,7 @@ struct sk_buff *ndisc_build_skb(struct net_device *dev,
 
         skb = sock_alloc_send_skb(sk,
                                   (MAX_HEADER + sizeof(struct ipv6hdr) +
-                                   len + LL_ALLOCATED_SPACE(dev)),
+                                   len + hlen + tlen),
                                   1, &err);
         if (!skb) {
                 ND_PRINTK0(KERN_ERR
@@ -468,7 +470,7 @@ struct sk_buff *ndisc_build_skb(struct net_device *dev,
                 return NULL;
         }
 
-        skb_reserve(skb, LL_RESERVED_SPACE(dev));
+        skb_reserve(skb, hlen);
         ip6_nd_hdr(sk, skb, dev, saddr, daddr, IPPROTO_ICMPV6, len);
 
         skb->transport_header = skb->tail;
@@ -1533,6 +1535,7 @@ void ndisc_send_redirect(struct sk_buff *skb, struct neighbour *neigh,
         struct inet6_dev *idev;
         struct flowi6 fl6;
         u8 *opt;
+        int hlen, tlen;
         int rd_len;
         int err;
         u8 ha_buf[MAX_ADDR_LEN], *ha = NULL;
@@ -1590,9 +1593,11 @@ void ndisc_send_redirect(struct sk_buff *skb, struct neighbour *neigh,
         rd_len &= ~0x7;
         len += rd_len;
 
+        hlen = LL_RESERVED_SPACE(dev);
+        tlen = dev->needed_tailroom;
         buff = sock_alloc_send_skb(sk,
                                    (MAX_HEADER + sizeof(struct ipv6hdr) +
-                                    len + LL_ALLOCATED_SPACE(dev)),
+                                    len + hlen + tlen),
                                    1, &err);
         if (buff == NULL) {
                 ND_PRINTK0(KERN_ERR
@@ -1601,7 +1606,7 @@ void ndisc_send_redirect(struct sk_buff *skb, struct neighbour *neigh,
                 goto release;
         }
 
-        skb_reserve(buff, LL_RESERVED_SPACE(dev));
+        skb_reserve(buff, hlen);
         ip6_nd_hdr(sk, buff, dev, &saddr_buf, &ipv6_hdr(skb)->saddr,
                    IPPROTO_ICMPV6, len);