7 files changed, 32 insertions, 2 deletions

diff --git a/include/linux/ktime.h b/include/linux/ktime.h
index c762954bda14..2b139f66027f 100644
--- a/include/linux/ktime.h
+++ b/include/linux/ktime.h
@@ -261,6 +261,18 @@ static inline s64 ktime_to_ns(const ktime_t kt)
 
 #endif
 
+/**
+ * ktime_equal - Compares two ktime_t variables to see if they are equal
+ * @cmp1:       comparable1
+ * @cmp2:       comparable2
+ *
+ * Compare two ktime_t variables, returns 1 if equal
+ */
+static inline int ktime_equal(const ktime_t cmp1, const ktime_t cmp2)
+{
+        return cmp1.tv64 == cmp2.tv64;
+}
+
 static inline s64 ktime_to_us(const ktime_t kt)
 {
         struct timeval tv = ktime_to_timeval(kt);
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index e7367c74e1bb..6f0b2f7d0010 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -1579,6 +1579,10 @@ static inline ktime_t net_timedelta(ktime_t t)
         return ktime_sub(ktime_get_real(), t);
 }
 
+static inline ktime_t net_invalid_timestamp(void)
+{
+        return ktime_set(0, 0);
+}
 
 extern __sum16 __skb_checksum_complete_head(struct sk_buff *skb, int len);
 extern __sum16 __skb_checksum_complete(struct sk_buff *skb);
diff --git a/net/ipv4/tcp_illinois.c b/net/ipv4/tcp_illinois.c
index 4adc47c55351..b2b2256d3b84 100644
--- a/net/ipv4/tcp_illinois.c
+++ b/net/ipv4/tcp_illinois.c
@@ -90,6 +90,9 @@ static void tcp_illinois_acked(struct sock *sk, u32 pkts_acked, ktime_t last)
 
         ca->acked = pkts_acked;
 
+        if (ktime_equal(last, net_invalid_timestamp()))
+                return;
+
         rtt = ktime_to_us(net_timedelta(last));
 
         /* ignore bogus values, this prevents wraparound in alpha math */
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index d6d0f9b6cdc6..aaf6f66677f9 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -2409,7 +2409,7 @@ static int tcp_clean_rtx_queue(struct sock *sk, __s32 *seq_rtt_p)
         int acked = 0;
         int prior_packets = tp->packets_out;
         __s32 seq_rtt = -1;
-        ktime_t last_ackt = ktime_set(0,0);
+        ktime_t last_ackt = net_invalid_timestamp();
 
         while ((skb = tcp_write_queue_head(sk)) &&
                skb != tcp_send_head(sk)) {
@@ -2487,6 +2487,10 @@ static int tcp_clean_rtx_queue(struct sock *sk, __s32 *seq_rtt_p)
                 tcp_ack_update_rtt(sk, acked, seq_rtt);
                 tcp_ack_packets_out(sk);
 
+                /* Is the ACK triggering packet unambiguous? */
+                if (acked & FLAG_RETRANS_DATA_ACKED)
+                        last_ackt = net_invalid_timestamp();
+
                 if (ca_ops->pkts_acked)
                         ca_ops->pkts_acked(sk, pkts_acked, last_ackt);
         }
diff --git a/net/ipv4/tcp_lp.c b/net/ipv4/tcp_lp.c
index 43294ad9f63e..e49836ce012e 100644
--- a/net/ipv4/tcp_lp.c
+++ b/net/ipv4/tcp_lp.c
@@ -266,7 +266,8 @@ static void tcp_lp_pkts_acked(struct sock *sk, u32 num_acked, ktime_t last)
         struct tcp_sock *tp = tcp_sk(sk);
         struct lp *lp = inet_csk_ca(sk);
 
-        tcp_lp_rtt_sample(sk,  ktime_to_us(net_timedelta(last)));
+        if (!ktime_equal(last, net_invalid_timestamp()))
+                tcp_lp_rtt_sample(sk,  ktime_to_us(net_timedelta(last)));
 
         /* calc inference */
         if (tcp_time_stamp > tp->rx_opt.rcv_tsecr)
diff --git a/net/ipv4/tcp_vegas.c b/net/ipv4/tcp_vegas.c
index 73e19cf7df21..e218a51ceced 100644
--- a/net/ipv4/tcp_vegas.c
+++ b/net/ipv4/tcp_vegas.c
@@ -117,6 +117,9 @@ void tcp_vegas_pkts_acked(struct sock *sk, u32 cnt, ktime_t last)
         struct vegas *vegas = inet_csk_ca(sk);
         u32 vrtt;
 
+        if (ktime_equal(last, net_invalid_timestamp()))
+                return;
+
         /* Never allow zero rtt or baseRTT */
         vrtt = ktime_to_us(net_timedelta(last)) + 1;
 
diff --git a/net/ipv4/tcp_veno.c b/net/ipv4/tcp_veno.c
index 9edb340f2f95..ec854cc5fad5 100644
--- a/net/ipv4/tcp_veno.c
+++ b/net/ipv4/tcp_veno.c
@@ -74,6 +74,9 @@ static void tcp_veno_pkts_acked(struct sock *sk, u32 cnt, ktime_t last)
         struct veno *veno = inet_csk_ca(sk);
         u32 vrtt;
 
+        if (ktime_equal(last, net_invalid_timestamp()))
+                return;
+
         /* Never allow zero rtt or baseRTT */
         vrtt = ktime_to_us(net_timedelta(last)) + 1;