From b3d6cb92fd190d720a01075c4d20cdca896663fc Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Mon, 15 Sep 2014 04:19:53 -0700 Subject: [PATCH] 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 Acked-by: Neal Cardwell Signed-off-by: David S. Miller --- net/ipv4/tcp_input.c | 17 ++--------------- 1 file changed, 2 insertions(+), 15 deletions(-) diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 228bf0c5ff19..ea92f23ffaf1 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -4535,26 +4535,13 @@ restart: 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); -- 2.20.1