+/* When a modification to fackets out becomes necessary, we need to check
+ * skb is counted to fackets_out or not. Another important thing is to
+ * tweak SACK fastpath hint too as it would overwrite all changes unless
+ * hint is also changed.
+ */
+static void tcp_adjust_fackets_out(struct tcp_sock *tp, struct sk_buff *skb,
+ int decr)
+{
+ if (!tp->sacked_out)
+ return;
+
+ if (!before(tp->highest_sack, TCP_SKB_CB(skb)->seq))
+ tp->fackets_out -= decr;
+
+ /* cnt_hint is "off-by-one" compared with fackets_out (see sacktag) */
+ if (tp->fastpath_skb_hint != NULL &&
+ after(TCP_SKB_CB(tp->fastpath_skb_hint)->seq, TCP_SKB_CB(skb)->seq))
+ tp->fastpath_cnt_hint -= decr;
+}
+