1 files changed, 8 insertions, 16 deletions

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 575d3c1fb6e8..9a1b3c1c1c14 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -1971,11 +1971,6 @@ void tcp_enter_loss(struct sock *sk)
         /* F-RTO RFC5682 sec 3.1 step 1: retransmit SND.UNA if no previous
          * loss recovery is underway except recurring timeout(s) on
          * the same SND.UNA (sec 3.2). Disable F-RTO on path MTU probing
-         *
-         * In theory F-RTO can be used repeatedly during loss recovery.
-         * In practice this interacts badly with broken middle-boxes that
-         * falsely raise the receive window, which results in repeated
-         * timeouts and stop-and-go behavior.
          */
         tp->frto = net->ipv4.sysctl_tcp_frto &&
                    (new_recovery || icsk->icsk_retransmits) &&
@@ -2631,18 +2626,14 @@ static void tcp_process_loss(struct sock *sk, int flag, bool is_dupack,
             tcp_try_undo_loss(sk, false))
                 return;
 
-        /* The ACK (s)acks some never-retransmitted data meaning not all
-         * the data packets before the timeout were lost. Therefore we
-         * undo the congestion window and state. This is essentially
-         * the operation in F-RTO (RFC5682 section 3.1 step 3.b). Since
-         * a retransmitted skb is permantly marked, we can apply such an
-         * operation even if F-RTO was not used.
-         */
-        if ((flag & FLAG_ORIG_SACK_ACKED) &&
-            tcp_try_undo_loss(sk, tp->undo_marker))
-                return;
-
         if (tp->frto) { /* F-RTO RFC5682 sec 3.1 (sack enhanced version). */
+                /* Step 3.b. A timeout is spurious if not all data are
+                 * lost, i.e., never-retransmitted data are (s)acked.
+                 */
+                if ((flag & FLAG_ORIG_SACK_ACKED) &&
+                    tcp_try_undo_loss(sk, true))
+                        return;
+
                 if (after(tp->snd_nxt, tp->high_seq)) {
                         if (flag & FLAG_DATA_SACKED || is_dupack)
                                 tp->frto = 0; /* Step 3.a. loss was real */
@@ -4001,6 +3992,7 @@ void tcp_reset(struct sock *sk)
         /* This barrier is coupled with smp_rmb() in tcp_poll() */
         smp_wmb();
 
+        tcp_write_queue_purge(sk);
         tcp_done(sk);
 
         if (!sock_flag(sk, SOCK_DEAD))