Subject: Re: [PATCH] net: sctp: fix a cacc_saw_newack missetting issue

From: Vlad Yasevich <[email-masked]>
Date: Tue, 15 Oct 2013 10:11:57 -0400

On 10/14/2013 09:33 AM, Chang Xiangzhong wrote:
> For for each TSN t being newly acked (Not only cumulatively,
> but also SELECTIVELY) cacc_saw_newack should be set to 1.
>
> Signed-off-by: Xiangzhong Chang <[email-masked]>
> ---
>   net/sctp/outqueue.c |   42 +++++++++++++++++++++---------------------
>   1 file changed, 21 insertions(+), 21 deletions(-)
>
> diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c
> index 94df758..d86032b 100644
> --- a/net/sctp/outqueue.c
> +++ b/net/sctp/outqueue.c
> @@ -1398,6 +1398,27 @@ static void sctp_check_transmitted(struct sctp_outq *q,
>   				forward_progress = true;
>   			}
>
> +			if (!tchunk->tsn_gap_acked) {

You can remove this test since the block just above already performs
it.  Just fold this code into the block above.

-vlad

> +				/*
> +				 * 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;
> +			}
> +
>   			if (TSN_lte(tsn, sack_ctsn)) {
>   				/* RFC 2960  6.3.2 Retransmission Timer Rules
>   				 *
> @@ -1411,27 +1432,6 @@ 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);
>