tcp: remove tp->lost_out guard to make joining diff nicer

The validity of the retransmit_high must then be ensured
if no L'ed skb exits!

This makes a minor change to behavior, we now have to
iterate the head to find out that the loop terminates.

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

1 files changed, 38 insertions, 37 deletions

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 2f24ecc37067..9f44be633ef6 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -2034,53 +2034,54 @@ void tcp_xmit_retransmit_queue(struct sock *sk)
         struct sk_buff *skb;
         int mib_idx;
 
+        if (!tp->lost_out)
+                tp->retransmit_high = tp->snd_una;
+
         if (tp->retransmit_skb_hint)
                 skb = tp->retransmit_skb_hint;
         else
                 skb = tcp_write_queue_head(sk);
 
         /* First pass: retransmit lost packets. */
-        if (tp->lost_out) {
-                tcp_for_write_queue_from(skb, sk) {
-                        __u8 sacked = TCP_SKB_CB(skb)->sacked;
+        tcp_for_write_queue_from(skb, sk) {
+                __u8 sacked = TCP_SKB_CB(skb)->sacked;
 
-                        if (skb == tcp_send_head(sk))
-                                break;
-                        /* we could do better than to assign each time */
-                        tp->retransmit_skb_hint = skb;
-
-                        /* Assume this retransmit will generate
-                         * only one packet for congestion window
-                         * calculation purposes.  This works because
-                         * tcp_retransmit_skb() will chop up the
-                         * packet to be MSS sized and all the
-                         * packet counting works out.
-                         */
-                        if (tcp_packets_in_flight(tp) >= tp->snd_cwnd)
-                                return;
-                        if (!before(TCP_SKB_CB(skb)->seq, tp->retransmit_high))
-                                break;
-                        if (sacked & (TCPCB_SACKED_ACKED|TCPCB_SACKED_RETRANS))
-                                continue;
+                if (skb == tcp_send_head(sk))
+                        break;
+                /* we could do better than to assign each time */
+                tp->retransmit_skb_hint = skb;
+
+                /* Assume this retransmit will generate
+                 * only one packet for congestion window
+                 * calculation purposes.  This works because
+                 * tcp_retransmit_skb() will chop up the
+                 * packet to be MSS sized and all the
+                 * packet counting works out.
+                 */
+                if (tcp_packets_in_flight(tp) >= tp->snd_cwnd)
+                        return;
+                if (!before(TCP_SKB_CB(skb)->seq, tp->retransmit_high))
+                        break;
+                if (sacked & (TCPCB_SACKED_ACKED|TCPCB_SACKED_RETRANS))
+                        continue;
 
-                        if (!(sacked & TCPCB_LOST))
-                                continue;
+                if (!(sacked & TCPCB_LOST))
+                        continue;
 
-                        if (tcp_retransmit_skb(sk, skb)) {
-                                tp->retransmit_skb_hint = NULL;
-                                return;
-                        }
-                        if (icsk->icsk_ca_state != TCP_CA_Loss)
-                                mib_idx = LINUX_MIB_TCPFASTRETRANS;
-                        else
-                                mib_idx = LINUX_MIB_TCPSLOWSTARTRETRANS;
-                        NET_INC_STATS_BH(sock_net(sk), mib_idx);
-
-                        if (skb == tcp_write_queue_head(sk))
-                                inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
-                                                          inet_csk(sk)->icsk_rto,
-                                                          TCP_RTO_MAX);
+                if (tcp_retransmit_skb(sk, skb)) {
+                        tp->retransmit_skb_hint = NULL;
+                        return;
                 }
+                if (icsk->icsk_ca_state != TCP_CA_Loss)
+                        mib_idx = LINUX_MIB_TCPFASTRETRANS;
+                else
+                        mib_idx = LINUX_MIB_TCPSLOWSTARTRETRANS;
+                NET_INC_STATS_BH(sock_net(sk), mib_idx);
+
+                if (skb == tcp_write_queue_head(sk))
+                        inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
+                                                  inet_csk(sk)->icsk_rto,
+                                                  TCP_RTO_MAX);
         }
 
         /* OK, demanded retransmission is finished. */