Freshly allocated skbs have their csum field cleared already.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
        struct tcp_sock *tp = tcp_sk(sk);
        struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
 
-       skb->csum    = 0;
        tcb->seq     = tcb->end_seq = tp->write_seq;
        tcb->tcp_flags = TCPHDR_ACK;
        tcb->sacked  = 0;
 
        TCP_SKB_CB(nskb)->end_seq = TCP_SKB_CB(skb)->seq + probe_size;
        TCP_SKB_CB(nskb)->tcp_flags = TCPHDR_ACK;
        TCP_SKB_CB(nskb)->sacked = 0;
-       nskb->csum = 0;
 
        tcp_insert_write_queue_before(nskb, skb, sk);
        tcp_highest_sack_replace(sk, skb, nskb);
 
        fl6.flowlabel = label;
 
        buff->ip_summed = CHECKSUM_PARTIAL;
-       buff->csum = 0;
 
        __tcp_v6_send_check(buff, &fl6.saddr, &fl6.daddr);