netdev - [PATCH net] tcp: increment retransmit counters in tlp and fast open

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Date:	Mon, 28 Apr 2014 22:00:29 -0700
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	David Miller <davem@...emloft.net>
Cc:	netdev <netdev@...r.kernel.org>,
	Nandita Dukkipati <nanditad@...gle.com>,
	Yuchung Cheng <ycheng@...gle.com>,
	Neal Cardwell <ncardwell@...gle.com>
Subject: [PATCH net] tcp: increment retransmit counters in tlp and fast open

From: Eric Dumazet <edumazet@...gle.com>

Both TLP and Fast Open call __tcp_retransmit_skb() instead of
tcp_retransmit_skb() to avoid changing tp->retrans_out.

This has the side effect of missing SNMP counters increments as well
as tcp_info tcpi_total_retrans updates.

Fix this by moving the stats increments of into __tcp_retransmit_skb()

Signed-off-by: Eric Dumazet <edumazet@...gle.com>
---
 net/ipv4/tcp_output.c |   14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 025e25093984..12d6016bdd9a 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -2441,8 +2441,14 @@ int __tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
 		err = tcp_transmit_skb(sk, skb, 1, GFP_ATOMIC);
 	}
 
-	if (likely(!err))
+	if (likely(!err)) {
 		TCP_SKB_CB(skb)->sacked |= TCPCB_EVER_RETRANS;
+		/* Update global TCP statistics. */
+		TCP_INC_STATS(sock_net(sk), TCP_MIB_RETRANSSEGS);
+		if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)
+			NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPSYNRETRANS);
+		tp->total_retrans++;
+	}
 	return err;
 }
 
@@ -2452,12 +2458,6 @@ int tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
 	int err = __tcp_retransmit_skb(sk, skb);
 
 	if (err == 0) {
-		/* Update global TCP statistics. */
-		TCP_INC_STATS(sock_net(sk), TCP_MIB_RETRANSSEGS);
-		if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)
-			NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPSYNRETRANS);
-		tp->total_retrans++;
-
 #if FASTRETRANS_DEBUG > 0
 		if (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_RETRANS) {
 			net_dbg_ratelimited("retrans_out leaked\n");


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