Re: [PATCH net 1/3] sctp: only update outstanding_bytes for transmitted queue when doing prsctp_prune

[Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>]

On Sat, Nov 25, 2017 at 09:18:34PM +0800, Xin Long wrote:
> Now outstanding_bytes is only increased when appending chunks into one
> packet and sending it at 1st time, while decreased when it is about to
> move into retransmit queue. It means outstanding_bytes value is already
> decreased for all chunks in retransmit queue.
> 
> However sctp_prsctp_prune_sent is a common function to check the chunks
> in both transmitted and retransmit queue, it decrease outstanding_bytes
> when moving a chunk into abandoned queue from either of them.
> 
> It could cause outstanding_bytes underflow, as it also decreases it's
> value for the chunks in retransmit queue.
> 
> This patch fixes it by only updating outstanding_bytes for transmitted
> queue when pruning queues for prsctp prio policy, the same fix is also
> needed in sctp_check_transmitted.
> 
> Fixes: 8dbdf1f5b09c ("sctp: implement prsctp PRIO policy")
> Signed-off-by: Xin Long <lucien.xin@gmail.com>

Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>

> ---
>  net/sctp/outqueue.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c
> index 4db012a..7029f8b 100644
> --- a/net/sctp/outqueue.c
> +++ b/net/sctp/outqueue.c
> @@ -377,7 +377,8 @@ static int sctp_prsctp_prune_sent(struct sctp_association *asoc,
>  		asoc->abandoned_sent[SCTP_PR_INDEX(PRIO)]++;
>  		streamout->ext->abandoned_sent[SCTP_PR_INDEX(PRIO)]++;
>  
> -		if (!chk->tsn_gap_acked) {
> +		if (queue != &asoc->outqueue.retransmit &&
> +		    !chk->tsn_gap_acked) {
>  			if (chk->transport)
>  				chk->transport->flight_size -=
>  						sctp_data_size(chk);
> @@ -1434,7 +1435,8 @@ static void sctp_check_transmitted(struct sctp_outq *q,
>  			/* If this chunk has not been acked, stop
>  			 * considering it as 'outstanding'.
>  			 */
> -			if (!tchunk->tsn_gap_acked) {
> +			if (transmitted_queue != &q->retransmit &&
> +			    !tchunk->tsn_gap_acked) {
>  				if (tchunk->transport)
>  					tchunk->transport->flight_size -=
>  							sctp_data_size(tchunk);
> -- 
> 2.1.0
> 
> --
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