netdev - [PATCH net 5/4] tcp: fix rcu usage around __sk_dst_get in tcp_update

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Message-Id: <1459468123-31474-1-git-send-email-hannes@stressinduktion.org>
Date:	Fri,  1 Apr 2016 01:48:43 +0200
From:	Hannes Frederic Sowa <hannes@...essinduktion.org>
To:	davem@...emloft.net
Cc:	netdev@...r.kernel.org, sasha.levin@...cle.com,
	daniel@...earbox.net, alexei.starovoitov@...il.com,
	mkubecek@...e.cz
Subject: [PATCH net 5/4] tcp: fix rcu usage around __sk_dst_get in tcp_update_metrics

Already another one fix I overlooked.

Signed-off-by: Hannes Frederic Sowa <hannes@...essinduktion.org>
---
 net/ipv4/tcp_metrics.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/net/ipv4/tcp_metrics.c b/net/ipv4/tcp_metrics.c
index 33a36648423e8b..196de79902819a 100644
--- a/net/ipv4/tcp_metrics.c
+++ b/net/ipv4/tcp_metrics.c
@@ -367,7 +367,7 @@ static struct tcp_metrics_block *tcp_get_metrics(struct sock *sk,
 void tcp_update_metrics(struct sock *sk)
 {
 	const struct inet_connection_sock *icsk = inet_csk(sk);
-	struct dst_entry *dst = __sk_dst_get(sk);
+	struct dst_entry *dst;
 	struct tcp_sock *tp = tcp_sk(sk);
 	struct net *net = sock_net(sk);
 	struct tcp_metrics_block *tm;
@@ -375,13 +375,14 @@ void tcp_update_metrics(struct sock *sk)
 	u32 val;
 	int m;
 
+	rcu_read_lock();
+	dst = __sk_dst_get(sk);
 	if (sysctl_tcp_nometrics_save || !dst)
-		return;
+		goto out_unlock;
 
 	if (dst->flags & DST_HOST)
 		dst_confirm(dst);
 
-	rcu_read_lock();
 	if (icsk->icsk_backoff || !tp->srtt_us) {
 		/* This session failed to estimate rtt. Why?
 		 * Probably, no packets returned in time.  Reset our
-- 
2.5.5