[PATCH 4.13 29/44] tcp: refresh tp timestamp before tcp_mtu_probe()

From: Greg Kroah-Hartman
Date: Thu Nov 16 2017 - 12:51:22 EST


4.13-stable review patch. If anyone has any objections, please let me know.

------------------

From: Eric Dumazet <edumazet@xxxxxxxxxx>


[ Upstream commit ee1836aec4f5a977c1699a311db4d9027ef21ac8 ]

In the unlikely event tcp_mtu_probe() is sending a packet, we
want tp->tcp_mstamp being as accurate as possible.

This means we need to call tcp_mstamp_refresh() a bit earlier in
tcp_write_xmit().

Fixes: 385e20706fac ("tcp: use tp->tcp_mstamp in output path")
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/ipv4/tcp_output.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -2271,6 +2271,7 @@ static bool tcp_write_xmit(struct sock *

sent_pkts = 0;

+ tcp_mstamp_refresh(tp);
if (!push_one) {
/* Do MTU probing. */
result = tcp_mtu_probe(sk);
@@ -2282,7 +2283,6 @@ static bool tcp_write_xmit(struct sock *
}

max_segs = tcp_tso_segs(sk, mss_now);
- tcp_mstamp_refresh(tp);
while ((skb = tcp_send_head(sk))) {
unsigned int limit;