Commit 547669d4 authored May 23, 2013 by Eric Dumazet Committed by David S. Miller May 23, 2013

tcp: xps: fix reordering issues



commit 3853b584 ("xps: Improvements in TX queue selection")
introduced ooo_okay flag, but the condition to set it is slightly wrong.

In our traces, we have seen ACK packets being received out of order,
and RST packets sent in response.

We should test if we have any packets still in host queue.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Tom Herbert <therbert@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 7a1a0cbf

net/ipv4/tcp_output.c

+6 −4

Original line number	Diff line number	Diff line
		@@ -874,11 +874,13 @@ static int tcp_transmit_skb(struct sock sk, struct sk_buff skb, int clone_it,
		&md5);
		tcp_header_size = tcp_options_size + sizeof(struct tcphdr);

		if (tcp_packets_in_flight(tp) == 0) {
		if (tcp_packets_in_flight(tp) == 0)
		tcp_ca_event(sk, CA_EVENT_TX_START);
		skb->ooo_okay = 1;
		} else
		skb->ooo_okay = 0;

		/* if no packet is in qdisc/device queue, then allow XPS to select
		* another queue.
		*/
		skb->ooo_okay = sk_wmem_alloc_get(sk) == 0;

		skb_push(skb, tcp_header_size);
		skb_reset_transport_header(skb);