[SCTP]: Send only 1 window update SACK per message.

Right now, every time we increase our rwnd by more then MTU bytes, we
trigger a SACK.  When processing large messages, this will generate a
SACK for almost every other SCTP fragment. However since we are freeing
the entire message at the same time, we might as well collapse the SACK
generation to 1.

Signed-off-by: Tsutomu Fujii <t-fujii@nb.jp.nec.com>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 28 insertions, 2 deletions

diff --git a/net/sctp/ulpevent.c b/net/sctp/ulpevent.c
index ba97f974f57..ee236784a6b 100644
--- a/net/sctp/ulpevent.c
+++ b/net/sctp/ulpevent.c
@@ -51,6 +51,8 @@
 static void sctp_ulpevent_receive_data(struct sctp_ulpevent *event,
                                        struct sctp_association *asoc);
 static void sctp_ulpevent_release_data(struct sctp_ulpevent *event);
+static void sctp_ulpevent_release_frag_data(struct sctp_ulpevent *event);
+
 
 /* Initialize an ULP event from an given skb.  */
 SCTP_STATIC void sctp_ulpevent_init(struct sctp_ulpevent *event, int msg_flags)
@@ -883,6 +885,7 @@ static void sctp_ulpevent_receive_data(struct sctp_ulpevent *event,
 static void sctp_ulpevent_release_data(struct sctp_ulpevent *event)
 {
         struct sk_buff *skb, *frag;
+        unsigned int    len;
 
         /* Current stack structures assume that the rcv buffer is
          * per socket.   For UDP style sockets this is not true as
@@ -892,7 +895,30 @@ static void sctp_ulpevent_release_data(struct sctp_ulpevent *event)
          */
 
         skb = sctp_event2skb(event);
-        sctp_assoc_rwnd_increase(event->asoc, skb_headlen(skb));
+        len = skb->len;
+
+        if (!skb->data_len)
+                goto done;
+
+        /* Don't forget the fragments. */
+        for (frag = skb_shinfo(skb)->frag_list; frag; frag = frag->next) {
+                /* NOTE:  skb_shinfos are recursive. Although IP returns
+                 * skb's with only 1 level of fragments, SCTP reassembly can
+                 * increase the levels.
+                 */
+                sctp_ulpevent_release_frag_data(sctp_skb2event(frag));
+        }
+
+done:
+        sctp_assoc_rwnd_increase(event->asoc, len);
+        sctp_ulpevent_release_owner(event);
+}
+
+static void sctp_ulpevent_release_frag_data(struct sctp_ulpevent *event)
+{
+        struct sk_buff *skb, *frag;
+
+        skb = sctp_event2skb(event);
 
         if (!skb->data_len)
                 goto done;
@@ -903,7 +929,7 @@ static void sctp_ulpevent_release_data(struct sctp_ulpevent *event)
                  * skb's with only 1 level of fragments, SCTP reassembly can
                  * increase the levels.
                  */
-                sctp_ulpevent_release_data(sctp_skb2event(frag));
+                sctp_ulpevent_release_frag_data(sctp_skb2event(frag));
         }
 
 done: