diff mbox series

[net-next] tcp: account total lost packets properly

Message ID 20201001210518.92495-1-ycheng@google.com
State New
Headers show
Series [net-next] tcp: account total lost packets properly | expand

Commit Message

Yuchung Cheng Oct. 1, 2020, 9:05 p.m. UTC 
The retransmission refactoring patch
686989700cab ("tcp: simplify tcp_mark_skb_lost")
does not properly update the total lost packet counter which may
break the policer mode in BBR. This patch fixes it.

Fixes: 686989700cab ("tcp: simplify tcp_mark_skb_lost")
Reported-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 net/ipv4/tcp_input.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

Comments

David Miller Oct. 3, 2020, 11:57 p.m. UTC | #1 
From: Yuchung Cheng <ycheng@google.com>
Date: Thu,  1 Oct 2020 14:05:18 -0700

> The retransmission refactoring patch
> 686989700cab ("tcp: simplify tcp_mark_skb_lost")
> does not properly update the total lost packet counter which may
> break the policer mode in BBR. This patch fixes it.
> 
> Fixes: 686989700cab ("tcp: simplify tcp_mark_skb_lost")
> Reported-by: Neal Cardwell <ncardwell@google.com>
> Signed-off-by: Yuchung Cheng <ycheng@google.com>
> Signed-off-by: Neal Cardwell <ncardwell@google.com>
> Signed-off-by: Eric Dumazet <edumazet@google.com>

Applied, thank you.
diff mbox series

Patch

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index f7b3e37d2198..20f89078fa8d 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -1020,6 +1020,14 @@  static void tcp_verify_retransmit_hint(struct tcp_sock *tp, struct sk_buff *skb)
 		tp->retransmit_skb_hint = skb;
 }
 
+/* Sum the number of packets on the wire we have marked as lost, and
+ * notify the congestion control module that the given skb was marked lost.
+ */
+static void tcp_notify_skb_loss_event(struct tcp_sock *tp, const struct sk_buff *skb)
+{
+	tp->lost += tcp_skb_pcount(skb);
+}
+
 void tcp_mark_skb_lost(struct sock *sk, struct sk_buff *skb)
 {
 	__u8 sacked = TCP_SKB_CB(skb)->sacked;
@@ -1036,10 +1044,12 @@  void tcp_mark_skb_lost(struct sock *sk, struct sk_buff *skb)
 			tp->retrans_out -= tcp_skb_pcount(skb);
 			NET_ADD_STATS(sock_net(sk), LINUX_MIB_TCPLOSTRETRANSMIT,
 				      tcp_skb_pcount(skb));
+			tcp_notify_skb_loss_event(tp, skb);
 		}
 	} else {
 		tp->lost_out += tcp_skb_pcount(skb);
 		TCP_SKB_CB(skb)->sacked |= TCPCB_LOST;
+		tcp_notify_skb_loss_event(tp, skb);
 	}
 }