3.3-stable review patch. If anyone has any objections, please let me know.
------------------ From: Yuchung Cheng <[email protected]> [ Upstream commit 1cebce36d660c83bd1353e41f3e66abd4686f215 ] When the cwnd reduction is done, ssthresh may be infinite if TCP enters CWR via ECN or F-RTO. If cwnd is not undone, i.e., undo_marker is set, tcp_complete_cwr() falsely set cwnd to the infinite ssthresh value. The correct operation is to keep cwnd intact because it has been updated in ECN or F-RTO. Signed-off-by: Yuchung Cheng <[email protected]> Acked-by: Neal Cardwell <[email protected]> Signed-off-by: David S. Miller <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- net/ipv4/tcp_input.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -2866,11 +2866,14 @@ static inline void tcp_complete_cwr(stru /* Do not moderate cwnd if it's already undone in cwr or recovery. */ if (tp->undo_marker) { - if (inet_csk(sk)->icsk_ca_state == TCP_CA_CWR) + if (inet_csk(sk)->icsk_ca_state == TCP_CA_CWR) { tp->snd_cwnd = min(tp->snd_cwnd, tp->snd_ssthresh); - else /* PRR */ + tp->snd_cwnd_stamp = tcp_time_stamp; + } else if (tp->snd_ssthresh < TCP_INFINITE_SSTHRESH) { + /* PRR algorithm. */ tp->snd_cwnd = tp->snd_ssthresh; - tp->snd_cwnd_stamp = tcp_time_stamp; + tp->snd_cwnd_stamp = tcp_time_stamp; + } } tcp_ca_event(sk, CA_EVENT_COMPLETE_CWR); } -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
