tcp: do not copy headers in tcp_collapse()
tcp_collapse() wants to shrink skb so that the overhead is minimal.
Now we store tcp flags into TCP_SKB_CB(skb)->tcp_flags, we no longer
need to keep around full headers.
Whole available space is dedicated to the payload.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 228bf0c..ea92f23 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -4535,26 +4535,13 @@
return;
while (before(start, end)) {
+ int copy = min_t(int, SKB_MAX_ORDER(0, 0), end - start);
struct sk_buff *nskb;
- unsigned int header = skb_headroom(skb);
- int copy = SKB_MAX_ORDER(header, 0);
- /* Too big header? This can happen with IPv6. */
- if (copy < 0)
- return;
- if (end - start < copy)
- copy = end - start;
- nskb = alloc_skb(copy + header, GFP_ATOMIC);
+ nskb = alloc_skb(copy, GFP_ATOMIC);
if (!nskb)
return;
- skb_set_mac_header(nskb, skb_mac_header(skb) - skb->head);
- skb_set_network_header(nskb, (skb_network_header(skb) -
- skb->head));
- skb_set_transport_header(nskb, (skb_transport_header(skb) -
- skb->head));
- skb_reserve(nskb, header);
- memcpy(nskb->head, skb->head, header);
memcpy(nskb->cb, skb->cb, sizeof(skb->cb));
TCP_SKB_CB(nskb)->seq = TCP_SKB_CB(nskb)->end_seq = start;
__skb_queue_before(list, skb, nskb);
