tcp: remove tcp_ecn_make_synack() socket argument

SYNACK packets might be sent without holding socket lock.

For DCTCP/ECN sake, we should call INET_ECN_xmit() while
socket lock is owned, and only when we init/change congestion control.

This also fixies a bug if congestion module is changed from
dctcp to another one on a listener : we now clear ECN bits
properly.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/tcp_cong.c b/net/ipv4/tcp_cong.c
index 93c4dc3..882caa4 100644 (file)
--- a/net/ipv4/tcp_cong.c
+++ b/net/ipv4/tcp_cong.c
@@ -173,6 +173,10 @@ out:
         */
        if (ca->get_info)
                memset(icsk->icsk_ca_priv, 0, sizeof(icsk->icsk_ca_priv));
+       if (ca->flags & TCP_CONG_NEEDS_ECN)
+               INET_ECN_xmit(sk);
+       else
+               INET_ECN_dontxmit(sk);
 }
 
 void tcp_init_congestion_control(struct sock *sk)
@@ -181,6 +185,10 @@ void tcp_init_congestion_control(struct sock *sk)
 
        if (icsk->icsk_ca_ops->init)
                icsk->icsk_ca_ops->init(sk);
+       if (tcp_ca_needs_ecn(sk))
+               INET_ECN_xmit(sk);
+       else
+               INET_ECN_dontxmit(sk);
 }
 
 static void tcp_reinit_congestion_control(struct sock *sk,
@@ -192,8 +200,8 @@ static void tcp_reinit_congestion_control(struct sock *sk,
        icsk->icsk_ca_ops = ca;
        icsk->icsk_ca_setsockopt = 1;
 
-       if (sk->sk_state != TCP_CLOSE && icsk->icsk_ca_ops->init)
-               icsk->icsk_ca_ops->init(sk);
+       if (sk->sk_state != TCP_CLOSE)
+               tcp_init_congestion_control(sk);
 }
 
 /* Manage refcounts on socket close. */

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 87392cb..ba61941 100644 (file)
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -357,14 +357,10 @@ static void tcp_ecn_clear_syn(struct sock *sk, struct sk_buff *skb)
 }
 
 static void
-tcp_ecn_make_synack(const struct request_sock *req, struct tcphdr *th,
-                   struct sock *sk)
+tcp_ecn_make_synack(const struct request_sock *req, struct tcphdr *th)
 {
-       if (inet_rsk(req)->ecn_ok) {
+       if (inet_rsk(req)->ecn_ok)
                th->ece = 1;
-               if (tcp_ca_needs_ecn(sk))
-                       INET_ECN_xmit(sk);
-       }
 }
 
 /* Set up ECN state for a packet on a ESTABLISHED socket that is about to
@@ -2998,7 +2994,7 @@ struct sk_buff *tcp_make_synack(struct sock *sk, struct dst_entry *dst,
        memset(th, 0, sizeof(struct tcphdr));
        th->syn = 1;
        th->ack = 1;
-       tcp_ecn_make_synack(req, th, sk);
+       tcp_ecn_make_synack(req, th);
        th->source = htons(ireq->ir_num);
        th->dest = ireq->ir_rmt_port;
        /* Setting of flags are superfluous here for callers (and ECE is