From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marcelo Ricardo Leitner Subject: Re: [PATCH net] sctp: fix the transports round robin issue when init is retransmitted Date: Thu, 10 Mar 2016 12:01:57 -0300 Message-ID: <20160310150156.GK31743@localhost.localdomain> References: <8d3cd163c84b30797f1123a7fc8a56f768801a87.1457595117.git.lucien.xin@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: network dev , linux-sctp@vger.kernel.org, davem@davemloft.net, Vlad Yasevich , daniel@iogearbox.net To: Xin Long Return-path: Received: from mx1.redhat.com ([209.132.183.28]:52086 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751821AbcCJPCA (ORCPT ); Thu, 10 Mar 2016 10:02:00 -0500 Content-Disposition: inline In-Reply-To: <8d3cd163c84b30797f1123a7fc8a56f768801a87.1457595117.git.lucien.xin@gmail.com> Sender: netdev-owner@vger.kernel.org List-ID: On Thu, Mar 10, 2016 at 03:31:57PM +0800, Xin Long wrote: > prior to this patch, at the beginning if we have two paths in one assoc, > they may have the same params other than the last_time_heard, it will try > the paths like this: > > 1st cycle > try trans1 fail. > then trans2 is selected.(cause it's last_time_heard is after trans1). > > 2nd cycle: > try trans2 fail > then trans2 is selected.(cause it's last_time_heard is after trans1). > > 3rd cycle: > try trans2 fail > then trans2 is selected.(cause it's last_time_heard is after trans1). > > .... > > trans1 will never have change to be selected, which is not what we expect. > we should keeping round robin all the paths if they are just added at the > beginning. > > So at first every tranport's last_time_heard should be initialized 0, so > that we ensure they have the same value at the beginning, only by this, > all the transports could get equal chance to be selected. > > Then for sctp_trans_elect_best, it should return the trans_next one when > *trans == *trans_next, so that we can try next if it fails, but now it > always return trans. so we can fix it by exchanging these two params when > we calls sctp_trans_elect_tie(). > > Fixes: 4c47af4d5eb2 ('net: sctp: rework multihoming retransmission path selection to rfc4960') > Signed-off-by: Xin Long Acked-by: Marcelo Ricardo Leitner > --- > net/sctp/associola.c | 2 +- > net/sctp/transport.c | 2 +- > 2 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/net/sctp/associola.c b/net/sctp/associola.c > index 2bf8ec9..cd87344 100644 > --- a/net/sctp/associola.c > +++ b/net/sctp/associola.c > @@ -1263,7 +1263,7 @@ static struct sctp_transport *sctp_trans_elect_best(struct sctp_transport *curr, > if (score_curr > score_best) > return curr; > else if (score_curr == score_best) > - return sctp_trans_elect_tie(curr, best); > + return sctp_trans_elect_tie(best, curr); > else > return best; > } > diff --git a/net/sctp/transport.c b/net/sctp/transport.c > index a431c14..d517153 100644 > --- a/net/sctp/transport.c > +++ b/net/sctp/transport.c > @@ -72,7 +72,7 @@ static struct sctp_transport *sctp_transport_init(struct net *net, > */ > peer->rto = msecs_to_jiffies(net->sctp.rto_initial); > > - peer->last_time_heard = ktime_get(); > + peer->last_time_heard = ktime_set(0, 0); > peer->last_time_ecne_reduced = jiffies; > > peer->param_flags = SPP_HB_DISABLE | > -- > 2.1.0 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-sctp" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >