tcp: Don't clear hints when tcp_fragmenting

1) We didn't remove any skbs, so no need to handle stale refs.

2) scoreboard_skb_hint is trivial, no timestamps were changed
   so no need to clear that one

3) lost_skb_hint needs tweaking similar to that of
   tcp_sacktag_one().

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 6 insertions, 1 deletions

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index fa3c81aa4e6a..3feab4d6929d 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -771,7 +771,6 @@ int tcp_fragment(struct sock *sk, struct sk_buff *skb, u32 len,
 
         BUG_ON(len > skb->len);
 
-        tcp_clear_retrans_hints_partial(tp);
         nsize = skb_headlen(skb) - len;
         if (nsize < 0)
                 nsize = 0;
@@ -854,6 +853,12 @@ int tcp_fragment(struct sock *sk, struct sk_buff *skb, u32 len,
                         tcp_verify_left_out(tp);
                 }
                 tcp_adjust_fackets_out(sk, skb, diff);
+
+                if (tp->lost_skb_hint &&
+                    before(TCP_SKB_CB(skb)->seq,
+                           TCP_SKB_CB(tp->lost_skb_hint)->seq) &&
+                    (tcp_is_fack(tp) || TCP_SKB_CB(skb)->sacked))
+                        tp->lost_cnt_hint -= diff;
         }
 
         /* Link BUFF into the send queue. */