1 files changed, 5 insertions, 7 deletions

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 0003d409fec5..1c2a73406261 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -2164,8 +2164,7 @@ static void tcp_mark_head_lost(struct sock *sk, int packets, int mark_head)
 {
         struct tcp_sock *tp = tcp_sk(sk);
         struct sk_buff *skb;
-        int cnt, oldcnt;
-        int err;
+        int cnt, oldcnt, lost;
         unsigned int mss;
         /* Use SACK to deduce losses of new sequences sent during recovery */
         const u32 loss_high = tcp_is_sack(tp) ?  tp->snd_nxt : tp->high_seq;
@@ -2205,9 +2204,10 @@ static void tcp_mark_head_lost(struct sock *sk, int packets, int mark_head)
                                 break;
 
                         mss = tcp_skb_mss(skb);
-                        err = tcp_fragment(sk, skb, (packets - oldcnt) * mss,
-                                           mss, GFP_ATOMIC);
-                        if (err < 0)
+                        /* If needed, chop off the prefix to mark as lost. */
+                        lost = (packets - oldcnt) * mss;
+                        if (lost < skb->len &&
+                            tcp_fragment(sk, skb, lost, mss, GFP_ATOMIC) < 0)
                                 break;
                         cnt = packets;
                 }
@@ -2366,8 +2366,6 @@ static void tcp_undo_cwnd_reduction(struct sock *sk, bool unmark_loss)
                         tp->snd_ssthresh = tp->prior_ssthresh;
                         tcp_ecn_withdraw_cwr(tp);
                 }
-        } else {
-                tp->snd_cwnd = max(tp->snd_cwnd, tp->snd_ssthresh);
         }
         tp->snd_cwnd_stamp = tcp_time_stamp;
         tp->undo_marker = 0;