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Commit 2594a2a9 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
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tcp: better use ooo_last_skb in tcp_data_queue_ofo() 



Willem noticed that we could avoid an rbtree lookup if the
the attempt to coalesce incoming skb to the last skb failed
for some reason.

Since most ooo additions are at the tail, this is definitely
worth adding a test and fast path.

Suggested-by: default avatarWillem de Bruijn <willemb@google.com>
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Cc: Yaogong Wang <wygivan@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent ed227099

net/ipv4/tcp_input.c

+7 −1
Original line number Diff line number Diff line
@@ -4461,6 +4461,12 @@ static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb) 
		skb = NULL;

		goto add_sack;

	}

	/* Can avoid an rbtree lookup if we are adding skb after ooo_last_skb */

	if (!before(seq, TCP_SKB_CB(tp->ooo_last_skb)->end_seq)) {

		parent = &tp->ooo_last_skb->rbnode;

		p = &parent->rb_right;

		goto insert;

	}



	/* Find place to insert this segment. Handle overlaps on the way. */

	parent = NULL;
@@ -4503,7 +4509,7 @@ static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb) 
		}

		p = &parent->rb_right;

	}



insert:

	/* Insert segment into RB tree. */

	rb_link_node(&skb->rbnode, parent, p);

	rb_insert_color(&skb->rbnode, &tp->out_of_order_queue);