From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vlad Yasevich Subject: Re: [PATCH net v2] sctp: donot reset the overall_error_count in SHUTDOWN_RECEIVE state Date: Wed, 26 Aug 2015 11:19:20 -0400 Message-ID: <55DDD8F8.4090400@gmail.com> References: <46eeeb896c5be2523e3d978d4a7ea9907d4301ee.1440329415.git.lucien.xin@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Cc: mleitner@redhat.com, tgraf@infradead.org, davem@davemloft.net To: Xin Long , network dev Return-path: Received: from mail-qg0-f50.google.com ([209.85.192.50]:35134 "EHLO mail-qg0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751690AbbHZPTX (ORCPT ); Wed, 26 Aug 2015 11:19:23 -0400 Received: by qgj62 with SMTP id 62so128174271qgj.2 for ; Wed, 26 Aug 2015 08:19:22 -0700 (PDT) In-Reply-To: <46eeeb896c5be2523e3d978d4a7ea9907d4301ee.1440329415.git.lucien.xin@gmail.com> Sender: netdev-owner@vger.kernel.org List-ID: On 08/23/2015 07:30 AM, Xin Long wrote: > commit f8d960524 fix the 0 peer.rwnd issue in SHUTDOWN_PENDING state through > not reseting the overall_error_count when receive a heartbeat, but the same > issue also exists in SHUTDOWN_RECEIVE state. > > so we change the condition to state < SCTP_STATE_SHUTDOWN_PENDING to reset the > overall_error_count when receive a heartbeat, which can avoid the issue happen > in SCTP_STATE_SHUTDOWN_RECEIVE. > > as to SCTP_STATE_SHUTDOWN_ACK_SENT and SCTP_STATE_SHUTDOWN_SENT state, with > this patch, it will not be affected by the heartbeat, cause these two states > have been taken charge of by t2 timer. > > Fixes: f8d960524 ("sctp: Enforce retransmission limit during shutdown") > Signed-off-by: Xin Long The code is OK, but the change log could use some help. How is this for the explanation: Commit f8d960524 ("sctp: Enforce retransmission limit during shutdown") fixed a problem with excessive retransmissions in the SHUTDOWN_PENDING by not resetting the association overall_error_count. This allowed the association to better enforce assoc.max_retrans limit. However, the same issue still exists when the association is in SHUTDOWN_RECEIVED state. In this state, HB-ACKs will continue to reset the overall_error_count for the association would extend the lifetime of association unnecessarily. This patch solves this by resetting the overall_error_count whenever the current state is small then SCTP_STATE_SHUTDOWN_PENDING. As a small side-effect, we end up also handling SCTP_STATE_SHUTDOWN_ACK_SENT and SCTP_STATE_SHUTDOWN_SENT states, but they are not really impacted because we disable Heartbeats in those states. Thanks -vlad > --- > net/sctp/sm_sideeffect.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/net/sctp/sm_sideeffect.c b/net/sctp/sm_sideeffect.c > index fef2acd..85e6f03 100644 > --- a/net/sctp/sm_sideeffect.c > +++ b/net/sctp/sm_sideeffect.c > @@ -702,7 +702,7 @@ static void sctp_cmd_transport_on(sctp_cmd_seq_t *cmds, > * outstanding data and rely on the retransmission limit be reached > * to shutdown the association. > */ > - if (t->asoc->state != SCTP_STATE_SHUTDOWN_PENDING) > + if (t->asoc->state < SCTP_STATE_SHUTDOWN_PENDING) > t->asoc->overall_error_count = 0; > > /* Clear the hb_sent flag to signal that we had a good >