Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit b3d6cb92 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

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: default avatarEric Dumazet <edumazet@google.com>
Acked-by: default avatarNeal Cardwell <ncardwell@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent e93a0435

net/ipv4/tcp_input.c

+2 −15
Original line number Original line Diff line number Diff line
@@ -4535,26 +4535,13 @@ tcp_collapse(struct sock *sk, struct sk_buff_head *list, 
		return;

		return;





	while (before(start, end)) {

	while (before(start, end)) {

		int copy = min_t(int, SKB_MAX_ORDER(0, 0), end - start);

		struct sk_buff *nskb;

		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. */

		nskb = alloc_skb(copy, GFP_ATOMIC);

		if (copy < 0)

			return;

		if (end - start < copy)

			copy = end - start;

		nskb = alloc_skb(copy + header, GFP_ATOMIC);

		if (!nskb)

		if (!nskb)

			return;

			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));

		memcpy(nskb->cb, skb->cb, sizeof(skb->cb));

		TCP_SKB_CB(nskb)->seq = TCP_SKB_CB(nskb)->end_seq = start;

		TCP_SKB_CB(nskb)->seq = TCP_SKB_CB(nskb)->end_seq = start;

		__skb_queue_before(list, skb, nskb);

		__skb_queue_before(list, skb, nskb);