From 4d4d3d1e8807d6aa9822eeedf7fe8500e1b7e38d Mon Sep 17 00:00:00 2001 From: Stephen Hemminger Date: Mon, 23 Apr 2007 22:32:11 -0700 Subject: [PATCH] [TCP]: Congestion control initialization. Change to defer congestion control initialization. If setsockopt() was used to change TCP_CONGESTION before connection is established, then protocols that use sequence numbers to keep track of one RTT interval (vegas, illinois, ...) get confused. Change the init hook to be called after handshake. Signed-off-by: Stephen Hemminger Signed-off-by: David S. Miller --- net/ipv4/tcp_cong.c | 23 +++++++++++++---------- 1 file changed, 13 insertions(+), 10 deletions(-) diff --git a/net/ipv4/tcp_cong.c b/net/ipv4/tcp_cong.c index 5c8caf4a124..34ae3f13483 100644 --- a/net/ipv4/tcp_cong.c +++ b/net/ipv4/tcp_cong.c @@ -77,18 +77,19 @@ void tcp_init_congestion_control(struct sock *sk) struct inet_connection_sock *icsk = inet_csk(sk); struct tcp_congestion_ops *ca; - if (icsk->icsk_ca_ops != &tcp_init_congestion_ops) - return; + /* if no choice made yet assign the current value set as default */ + if (icsk->icsk_ca_ops == &tcp_init_congestion_ops) { + rcu_read_lock(); + list_for_each_entry_rcu(ca, &tcp_cong_list, list) { + if (try_module_get(ca->owner)) { + icsk->icsk_ca_ops = ca; + break; + } - rcu_read_lock(); - list_for_each_entry_rcu(ca, &tcp_cong_list, list) { - if (try_module_get(ca->owner)) { - icsk->icsk_ca_ops = ca; - break; + /* fallback to next available */ } - + rcu_read_unlock(); } - rcu_read_unlock(); if (icsk->icsk_ca_ops->init) icsk->icsk_ca_ops->init(sk); @@ -236,6 +237,7 @@ int tcp_set_congestion_control(struct sock *sk, const char *name) rcu_read_lock(); ca = tcp_ca_find(name); + /* no change asking for existing value */ if (ca == icsk->icsk_ca_ops) goto out; @@ -261,7 +263,8 @@ int tcp_set_congestion_control(struct sock *sk, const char *name) else { tcp_cleanup_congestion_control(sk); icsk->icsk_ca_ops = ca; - if (icsk->icsk_ca_ops->init) + + if (sk->sk_state != TCP_CLOSE && icsk->icsk_ca_ops->init) icsk->icsk_ca_ops->init(sk); } out: -- 2.39.5