5.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Eric Dumazet <edumazet@xxxxxxxxxx>
commit 0d580fbd2db084a5c96ee9c00492236a279d5e0f upstream.
It appears linux-4.14 stable needs a backport of commit
88f8598d0a30 ("tcp: exit if nothing to retransmit on RTO timeout")
Since tcp_rtx_queue_empty() is not in pre 4.15 kernels,
let's refactor tcp_retransmit_timer() to only use tcp_rtx_queue_head()
I will provide to stable teams the squashed patches.
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Cc: Willem de Bruijn <willemb@xxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Acked-by: Soheil Hassas Yeganeh <soheil@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/ipv4/tcp_timer.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
--- a/net/ipv4/tcp_timer.c
+++ b/net/ipv4/tcp_timer.c
@@ -452,6 +452,7 @@ void tcp_retransmit_timer(struct sock *s
struct net *net = sock_net(sk);
struct inet_connection_sock *icsk = inet_csk(sk);
struct request_sock *req;
+ struct sk_buff *skb;
req = rcu_dereference_protected(tp->fastopen_rsk,
lockdep_sock_is_held(sk));
@@ -464,7 +465,12 @@ void tcp_retransmit_timer(struct sock *s
*/
return;
}
- if (!tp->packets_out || WARN_ON_ONCE(tcp_rtx_queue_empty(sk)))
+
+ if (!tp->packets_out)
+ return;
+
+ skb = tcp_rtx_queue_head(sk);
+ if (WARN_ON_ONCE(!skb))
return;
if (!tp->snd_wnd && !sock_flag(sk, SOCK_DEAD) &&
@@ -496,7 +502,7 @@ void tcp_retransmit_timer(struct sock *s
goto out;
}
tcp_enter_loss(sk);
- tcp_retransmit_skb(sk, tcp_rtx_queue_head(sk), 1);
+ tcp_retransmit_skb(sk, skb, 1);
__sk_dst_reset(sk);
goto out_reset_timer;
}
