On Tue, Apr 24, 2018 at 06:17:35PM -0300, Marcelo Ricardo Leitner wrote:
> It's currently written as:
> 
> if (!tchunk->tsn_gap_acked) {   [1]
>       tchunk->tsn_gap_acked = 1;
>       ...
> }
> 
> if (TSN_lte(tsn, sack_ctsn)) {
>       if (!tchunk->tsn_gap_acked) {
>               /* SFR-CACC processing */
>               ...
>       }
> }
> 
> Which causes the SFR-CACC processing on ack reception to never process,
> as tchunk->tsn_gap_acked is always true by then. Block [1] was
> moved to that position by the commit marked below.
> 
> This patch fixes it by doing SFR-CACC processing earlier, before
> tsn_gap_acked is set to true.
> 
> Fixes: 31b02e154940 ("sctp: Failover transmitted list on transport delete")
> Signed-off-by: Marcelo Ricardo Leitner <marcelo.leit...@gmail.com>
> ---
> 
> Even though this is a -stable candidate, please apply it to net-next
> to avoid conflicts with subsequent patches in my queue. Thanks.
> 
>  net/sctp/outqueue.c | 48 +++++++++++++++++++++++-------------------------
>  1 file changed, 23 insertions(+), 25 deletions(-)
> 
> diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c
> index 
> f211b3db6a3543073e113da121bb28518b0af491..dee7cbd5483149024f2f3195db2fe4d473b1a00a
>  100644
> --- a/net/sctp/outqueue.c
> +++ b/net/sctp/outqueue.c
> @@ -1457,7 +1457,7 @@ static void sctp_check_transmitted(struct sctp_outq *q,
>                        * the outstanding bytes for this chunk, so only
>                        * count bytes associated with a transport.
>                        */
> -                     if (transport) {
> +                     if (transport && !tchunk->tsn_gap_acked) {
>                               /* If this chunk is being used for RTT
>                                * measurement, calculate the RTT and update
>                                * the RTO using this value.
> @@ -1469,14 +1469,34 @@ static void sctp_check_transmitted(struct sctp_outq 
> *q,
>                                * first instance of the packet or a later
>                                * instance).
>                                */
> -                             if (!tchunk->tsn_gap_acked &&
> -                                 !sctp_chunk_retransmitted(tchunk) &&
> +                             if (!sctp_chunk_retransmitted(tchunk) &&
>                                   tchunk->rtt_in_progress) {
>                                       tchunk->rtt_in_progress = 0;
>                                       rtt = jiffies - tchunk->sent_at;
>                                       sctp_transport_update_rto(transport,
>                                                                 rtt);
>                               }
> +
> +                             if (TSN_lte(tsn, sack_ctsn)) {
> +                                     /*
> +                                      * SFR-CACC algorithm:
> +                                      * 2) If the SACK contains gap acks
> +                                      * and the flag CHANGEOVER_ACTIVE is
> +                                      * set the receiver of the SACK MUST
> +                                      * take the following action:
> +                                      *
> +                                      * B) For each TSN t being acked that
> +                                      * has not been acked in any SACK so
> +                                      * far, set cacc_saw_newack to 1 for
> +                                      * the destination that the TSN was
> +                                      * sent to.
> +                                      */
> +                                     if (sack->num_gap_ack_blocks &&
> +                                         q->asoc->peer.primary_path->cacc.
> +                                         changeover_active)
> +                                             transport->cacc.cacc_saw_newack
> +                                                     = 1;
> +                             }
>                       }
> 
>                       /* If the chunk hasn't been marked as ACKED,
> @@ -1508,28 +1528,6 @@ static void sctp_check_transmitted(struct sctp_outq *q,
>                               restart_timer = 1;
>                               forward_progress = true;
> 
> -                             if (!tchunk->tsn_gap_acked) {
> -                                     /*
> -                                      * SFR-CACC algorithm:
> -                                      * 2) If the SACK contains gap acks
> -                                      * and the flag CHANGEOVER_ACTIVE is
> -                                      * set the receiver of the SACK MUST
> -                                      * take the following action:
> -                                      *
> -                                      * B) For each TSN t being acked that
> -                                      * has not been acked in any SACK so
> -                                      * far, set cacc_saw_newack to 1 for
> -                                      * the destination that the TSN was
> -                                      * sent to.
> -                                      */
> -                                     if (transport &&
> -                                         sack->num_gap_ack_blocks &&
> -                                         q->asoc->peer.primary_path->cacc.
> -                                         changeover_active)
> -                                             transport->cacc.cacc_saw_newack
> -                                                     = 1;
> -                             }
> -
>                               list_add_tail(&tchunk->transmitted_list,
>                                             &q->sacked);
>                       } else {
> --
> 2.14.3
> 
> 
Acked-by: Neil Horman <nhor...@tuxdriver.com>

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