From: Eric Dumazet <edumazet@google.com>
Date: Fri, 22 Sep 2023 22:03:54 +0000 (+0000)
Subject: tcp_metrics: properly set tp->snd_ssthresh in tcp_init_metrics()
X-Git-Tag: v4.14.330~44
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=568e546fccfc836e817bc0476cdfa72fbcbdace2;p=thirdparty%2Fkernel%2Fstable.git

tcp_metrics: properly set tp->snd_ssthresh in tcp_init_metrics()

[ Upstream commit 081480014a64a69d901f8ef1ffdd56d6085cf87e ]

We need to set tp->snd_ssthresh to TCP_INFINITE_SSTHRESH
in the case tcp_get_metrics() fails for some reason.

Fixes: 9ad7c049f0f7 ("tcp: RFC2988bis + taking RTT sample from 3WHS for the passive open side")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

diff --git a/net/ipv4/tcp_metrics.c b/net/ipv4/tcp_metrics.c
index 11bb9751a799f..164e917d71b21 100644
--- a/net/ipv4/tcp_metrics.c
+++ b/net/ipv4/tcp_metrics.c
@@ -467,6 +467,10 @@ void tcp_init_metrics(struct sock *sk)
 	u32 val, crtt = 0; /* cached RTT scaled by 8 */
 
 	sk_dst_confirm(sk);
+	/* ssthresh may have been reduced unnecessarily during.
+	 * 3WHS. Restore it back to its initial default.
+	 */
+	tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
 	if (!dst)
 		goto reset;
 
@@ -485,11 +489,6 @@ void tcp_init_metrics(struct sock *sk)
 		tp->snd_ssthresh = val;
 		if (tp->snd_ssthresh > tp->snd_cwnd_clamp)
 			tp->snd_ssthresh = tp->snd_cwnd_clamp;
-	} else {
-		/* ssthresh may have been reduced unnecessarily during.
-		 * 3WHS. Restore it back to its initial default.
-		 */
-		tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
 	}
 	val = tcp_metric_get(tm, TCP_METRIC_REORDERING);
 	if (val && tp->reordering != val) {