sctp: Only mark chunks as missing when there are gaps

Frist small step in optimizing SACK processing.   Do not call
sctp_mark_missing() when there are no gaps reported and thus
not missing chunks.

Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>

1 files changed, 12 insertions, 9 deletions

diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c
index 4328ad5439c9..ef5ea7423cc8 100644
--- a/net/sctp/outqueue.c
+++ b/net/sctp/outqueue.c
@@ -1129,12 +1129,13 @@ int sctp_outq_sack(struct sctp_outq *q, struct sctp_sackhdr *sack)
         unsigned outstanding;
         struct sctp_transport *primary = asoc->peer.primary_path;
         int count_of_newacks = 0;
+        int gap_ack_blocks;
 
         /* Grab the association's destination address list. */
         transport_list = &asoc->peer.transport_addr_list;
 
         sack_ctsn = ntohl(sack->cum_tsn_ack);
-
+        gap_ack_blocks = ntohs(sack->num_gap_ack_blocks);
         /*
          * SFR-CACC algorithm:
          * On receipt of a SACK the sender SHOULD execute the
@@ -1161,7 +1162,7 @@ int sctp_outq_sack(struct sctp_outq *q, struct sctp_sackhdr *sack)
          * A) Initialize the cacc_saw_newack to 0 for all destination
          * addresses.
          */
-        if (sack->num_gap_ack_blocks &&
+        if (gap_ack_blocks &&
             primary->cacc.changeover_active) {
                 list_for_each_entry(transport, transport_list, transports) {
                         transport->cacc.cacc_saw_newack = 0;
@@ -1170,9 +1171,8 @@ int sctp_outq_sack(struct sctp_outq *q, struct sctp_sackhdr *sack)
 
         /* Get the highest TSN in the sack. */
         highest_tsn = sack_ctsn;
-        if (sack->num_gap_ack_blocks)
-                highest_tsn +=
-                    ntohs(frags[ntohs(sack->num_gap_ack_blocks) - 1].gab.end);
+        if (gap_ack_blocks)
+                highest_tsn += ntohs(frags[gap_ack_blocks - 1].gab.end);
 
         if (TSN_lt(asoc->highest_sacked, highest_tsn)) {
                 highest_new_tsn = highest_tsn;
@@ -1181,11 +1181,11 @@ int sctp_outq_sack(struct sctp_outq *q, struct sctp_sackhdr *sack)
                 highest_new_tsn = sctp_highest_new_tsn(sack, asoc);
         }
 
+
         /* Run through the retransmit queue.  Credit bytes received
          * and free those chunks that we can.
          */
         sctp_check_transmitted(q, &q->retransmit, NULL, sack, highest_new_tsn);
-        sctp_mark_missing(q, &q->retransmit, NULL, highest_new_tsn, 0);
 
         /* Run through the transmitted queue.
          * Credit bytes received and free those chunks which we can.
@@ -1204,9 +1204,12 @@ int sctp_outq_sack(struct sctp_outq *q, struct sctp_sackhdr *sack)
                         count_of_newacks ++;
         }
 
-        list_for_each_entry(transport, transport_list, transports) {
-                sctp_mark_missing(q, &transport->transmitted, transport,
-                                  highest_new_tsn, count_of_newacks);
+        if (gap_ack_blocks) {
+                sctp_mark_missing(q, &q->retransmit, NULL, highest_new_tsn, 0);
+
+                list_for_each_entry(transport, transport_list, transports)
+                        sctp_mark_missing(q, &transport->transmitted, transport,
+                                          highest_new_tsn, count_of_newacks);
         }
 
         /* Move the Cumulative TSN Ack Point if appropriate.  */