sctp: only update outstanding_bytes for transmitted queue when doing prsctp_prune

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>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c
index 4db012a..7029f8b 100644 (file)
--- 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);