[TCP]: Account skb overhead in tcp_fragment

Make sure that we get the full sizeof(struct sk_buff)
plus the data size accounted for in skb->truesize.

This will create invariants that will allow adding
assertion checks on skb->truesize.

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

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 44df1db..a28ae59 100644 (file)
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -533,6 +533,7 @@ int tcp_fragment(struct sock *sk, struct sk_buff *skb, u32 len, unsigned int mss
        struct tcp_sock *tp = tcp_sk(sk);
        struct sk_buff *buff;
        int nsize, old_factor;
+       int nlen;
        u16 flags;
 
        BUG_ON(len > skb->len);
@@ -552,8 +553,10 @@ int tcp_fragment(struct sock *sk, struct sk_buff *skb, u32 len, unsigned int mss
        if (buff == NULL)
                return -ENOMEM; /* We'll just try again later. */
 
-       buff->truesize = skb->len - len;
-       skb->truesize -= buff->truesize;
+       sk_charge_skb(sk, buff);
+       nlen = skb->len - len - nsize;
+       buff->truesize += nlen;
+       skb->truesize -= nlen;
 
        /* Correct the sequence numbers. */
        TCP_SKB_CB(buff)->seq = TCP_SKB_CB(skb)->seq + len;
@@ -1039,7 +1042,8 @@ static int tso_fragment(struct sock *sk, struct sk_buff *skb, unsigned int len,
        if (unlikely(buff == NULL))
                return -ENOMEM;
 
-       buff->truesize = nlen;
+       sk_charge_skb(sk, buff);
+       buff->truesize += nlen;
        skb->truesize -= nlen;
 
        /* Correct the sequence numbers. */