--- /dev/null
+From 74b120c45aebf4278e1dedc55f5fa24d8ea83cdc Mon Sep 17 00:00:00 2001
+From: Eric Dumazet <edumazet@google.com>
+Date: Mon, 23 Jul 2018 09:28:21 -0700
+Subject: tcp: add tcp_ooo_try_coalesce() helper
+
+commit 58152ecbbcc6a0ce7fddd5bf5f6ee535834ece0c upstream.
+
+In case skb in out_or_order_queue is the result of
+multiple skbs coalescing, we would like to get a proper gso_segs
+counter tracking, so that future tcp_drop() can report an accurate
+number.
+
+I chose to not implement this tracking for skbs in receive queue,
+since they are not dropped, unless socket is disconnected.
+
+Signed-off-by: Eric Dumazet <edumazet@google.com>
+Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
+Acked-by: Yuchung Cheng <ycheng@google.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ net/ipv4/tcp_input.c | 23 +++++++++++++++++++++--
+ 1 file changed, 21 insertions(+), 2 deletions(-)
+
+diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
+index a9be8df108b4..9d0b73aa649f 100644
+--- a/net/ipv4/tcp_input.c
++++ b/net/ipv4/tcp_input.c
+@@ -4370,6 +4370,23 @@ static bool tcp_try_coalesce(struct sock *sk,
+ return true;
+ }
+
++static bool tcp_ooo_try_coalesce(struct sock *sk,
++ struct sk_buff *to,
++ struct sk_buff *from,
++ bool *fragstolen)
++{
++ bool res = tcp_try_coalesce(sk, to, from, fragstolen);
++
++ /* In case tcp_drop() is called later, update to->gso_segs */
++ if (res) {
++ u32 gso_segs = max_t(u16, 1, skb_shinfo(to)->gso_segs) +
++ max_t(u16, 1, skb_shinfo(from)->gso_segs);
++
++ skb_shinfo(to)->gso_segs = min_t(u32, gso_segs, 0xFFFF);
++ }
++ return res;
++}
++
+ static void tcp_drop(struct sock *sk, struct sk_buff *skb)
+ {
+ sk_drops_add(sk, skb);
+@@ -4493,7 +4510,8 @@ static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb)
+ /* In the typical case, we are adding an skb to the end of the list.
+ * Use of ooo_last_skb avoids the O(Log(N)) rbtree lookup.
+ */
+- if (tcp_try_coalesce(sk, tp->ooo_last_skb, skb, &fragstolen)) {
++ if (tcp_ooo_try_coalesce(sk, tp->ooo_last_skb,
++ skb, &fragstolen)) {
+ coalesce_done:
+ tcp_grow_window(sk, skb);
+ kfree_skb_partial(skb, fragstolen);
+@@ -4543,7 +4561,8 @@ coalesce_done:
+ tcp_drop(sk, skb1);
+ goto merge_right;
+ }
+- } else if (tcp_try_coalesce(sk, skb1, skb, &fragstolen)) {
++ } else if (tcp_ooo_try_coalesce(sk, skb1,
++ skb, &fragstolen)) {
+ goto coalesce_done;
+ }
+ p = &parent->rb_right;
+--
+cgit 1.2-0.3.lf.el7
+