4 files changed, 17 insertions, 18 deletions

diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c
index 0a7c22598d62..50dac01e48c5 100644
--- a/net/dccp/ccids/ccid3.c
+++ b/net/dccp/ccids/ccid3.c
@@ -767,15 +767,7 @@ static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
                  */
                 if (sample != 0)
                         hcrx->rtt = tfrc_ewma(hcrx->rtt, sample, 9);
-
-        } else if (tfrc_lh_update_i_mean(&hcrx->li_hist, skb)) {
-                /*
-                 * Step (3) of [RFC 3448, 6.1]: Recompute I_mean and, if I_mean
-                 * has decreased (resp. p has increased), send feedback now.
-                 */
-                do_feedback = CCID3_FBACK_PARAM_CHANGE;
         }
-
         /*
          * Check if the periodic once-per-RTT feedback is due; RFC 4342, 10.3
          */
diff --git a/net/dccp/ccids/lib/loss_interval.c b/net/dccp/ccids/lib/loss_interval.c
index 5b3ce0688c5c..fe5c2a31c770 100644
--- a/net/dccp/ccids/lib/loss_interval.c
+++ b/net/dccp/ccids/lib/loss_interval.c
@@ -86,21 +86,26 @@ static void tfrc_lh_calc_i_mean(struct tfrc_loss_hist *lh)
 
 /**
  * tfrc_lh_update_i_mean  -  Update the `open' loss interval I_0
- * For recomputing p: returns `true' if p > p_prev  <=>  1/p < 1/p_prev
+ * This updates I_mean as the sequence numbers increase. As a consequence, the
+ * open loss interval I_0 increases, hence p = W_tot/max(I_tot0, I_tot1)
+ * decreases, and thus there is no need to send renewed feedback.
  */
-u8 tfrc_lh_update_i_mean(struct tfrc_loss_hist *lh, struct sk_buff *skb)
+void tfrc_lh_update_i_mean(struct tfrc_loss_hist *lh, struct sk_buff *skb)
 {
         struct tfrc_loss_interval *cur = tfrc_lh_peek(lh);
-        u32 old_i_mean = lh->i_mean;
         s64 len;
 
         if (cur == NULL)                        /* not initialised */
-                return 0;
+                return;
+
+        /* FIXME: should probably also count non-data packets (RFC 4342, 6.1) */
+        if (!dccp_data_packet(skb))
+                return;
 
         len = dccp_delta_seqno(cur->li_seqno, DCCP_SKB_CB(skb)->dccpd_seq) + 1;
 
         if (len - (s64)cur->li_length <= 0)     /* duplicate or reordered */
-                return 0;
+                return;
 
         if (SUB16(dccp_hdr(skb)->dccph_ccval, cur->li_ccval) > 4)
                 /*
@@ -114,14 +119,11 @@ u8 tfrc_lh_update_i_mean(struct tfrc_loss_hist *lh, struct sk_buff *skb)
                 cur->li_is_closed = 1;
 
         if (tfrc_lh_length(lh) == 1)            /* due to RFC 3448, 6.3.1 */
-                return 0;
+                return;
 
         cur->li_length = len;
         tfrc_lh_calc_i_mean(lh);
-
-        return (lh->i_mean < old_i_mean);
 }
-EXPORT_SYMBOL_GPL(tfrc_lh_update_i_mean);
 
 /* Determine if `new_loss' does begin a new loss interval [RFC 4342, 10.2] */
 static inline u8 tfrc_lh_is_new_loss(struct tfrc_loss_interval *cur,
diff --git a/net/dccp/ccids/lib/loss_interval.h b/net/dccp/ccids/lib/loss_interval.h
index 246018a3b269..f101ae2cf528 100644
--- a/net/dccp/ccids/lib/loss_interval.h
+++ b/net/dccp/ccids/lib/loss_interval.h
@@ -69,7 +69,7 @@ struct tfrc_rx_hist;
 
 extern int  tfrc_lh_interval_add(struct tfrc_loss_hist *, struct tfrc_rx_hist *,
                                  u32 (*first_li)(struct sock *), struct sock *);
-extern u8   tfrc_lh_update_i_mean(struct tfrc_loss_hist *lh, struct sk_buff *);
+extern void tfrc_lh_update_i_mean(struct tfrc_loss_hist *lh, struct sk_buff *);
 extern void tfrc_lh_cleanup(struct tfrc_loss_hist *lh);
 
 #endif /* _DCCP_LI_HIST_ */
diff --git a/net/dccp/ccids/lib/packet_history.c b/net/dccp/ccids/lib/packet_history.c
index 8db34225c002..8ea96903033d 100644
--- a/net/dccp/ccids/lib/packet_history.c
+++ b/net/dccp/ccids/lib/packet_history.c
@@ -351,6 +351,11 @@ int tfrc_rx_handle_loss(struct tfrc_rx_hist *h,
                 is_new_loss = tfrc_lh_interval_add(lh, h, calc_first_li, sk);
                 __three_after_loss(h);
         }
+
+        /* RFC 3448, 6.1: update I_0, whose growth implies p <= p_prev */
+        if (!is_new_loss)
+                tfrc_lh_update_i_mean(lh, skb);
+
         return is_new_loss;
 }
 EXPORT_SYMBOL_GPL(tfrc_rx_handle_loss);