From b9f1f1ce866c28e3d9b86202441b220244754a69 Mon Sep 17 00:00:00 2001
From: Eric Dumazet <edumazet@google.com>
Date: Mon, 16 Oct 2017 19:38:35 -0700
Subject: [PATCH] tcp: fix tcp_xmit_retransmit_queue() after rbtree
introduction
I tried to hard avoiding a call to rb_first() (via tcp_rtx_queue_head)
in tcp_xmit_retransmit_queue(). But this was probably too bold.
Quoting Yuchung :
We might miss re-arming the RTO if tp->retransmit_skb_hint is not NULL.
This can happen when RACK marks the first packet lost again and resets
tp->retransmit_skb_hint for example (tcp_rack_mark_skb_lost())
Fixes: 75c119afe14f ("tcp: implement rb-tree based retransmit queue")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/ipv4/tcp_output.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 6c74f2a397787..53dc1267c85e6 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -2921,7 +2921,7 @@ int tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb, int segs)
void tcp_xmit_retransmit_queue(struct sock *sk)
{
const struct inet_connection_sock *icsk = inet_csk(sk);
- struct sk_buff *skb, *rtx_head = NULL, *hole = NULL;
+ struct sk_buff *skb, *rtx_head, *hole = NULL;
struct tcp_sock *tp = tcp_sk(sk);
u32 max_segs;
int mib_idx;
@@ -2929,11 +2929,8 @@ void tcp_xmit_retransmit_queue(struct sock *sk)
if (!tp->packets_out)
return;
- skb = tp->retransmit_skb_hint;
- if (!skb) {
- rtx_head = tcp_rtx_queue_head(sk);
- skb = rtx_head;
- }
+ rtx_head = tcp_rtx_queue_head(sk);
+ skb = tp->retransmit_skb_hint ?: rtx_head;
max_segs = tcp_tso_segs(sk, tcp_current_mss(sk));
skb_rbtree_walk_from(skb) {
__u8 sacked;
--
2.39.5