+ /* Adjust counters and hints for the newly sacked sequence
+ * range but discard the return value since prev is already
+ * marked. We must tag the range first because the seq
+ * advancement below implicitly advances
+ * tcp_highest_sack_seq() when skb is highest_sack.
+ */
+ tcp_sacktag_one(sk, state, TCP_SKB_CB(skb)->sacked,
+ start_seq, end_seq, dup_sack, pcount);
+