tcp: tcp_mark_head_lost is only valid for sack-tcp

so tcp_is_sack/reno checks are removed from tcp_mark_head_lost.

Signed-off-by: zhang kai <zhangkaiheb@126.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 66e55e5..7529c28 100644 (file)
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -2183,8 +2183,7 @@ static bool tcp_time_to_recover(struct sock *sk, int flag)
 }
 
 /* Detect loss in event "A" above by marking head of queue up as lost.
- * For non-SACK(Reno) senders, the first "packets" number of segments
- * are considered lost. For RFC3517 SACK, a segment is considered lost if it
+ * For RFC3517 SACK, a segment is considered lost if it
  * has at least tp->reordering SACKed seqments above it; "packets" refers to
  * the maximum SACKed segments to pass before reaching this limit.
  */
@@ -2192,10 +2191,9 @@ 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, lost;
-       unsigned int mss;
+       int cnt;
        /* 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;
+       const u32 loss_high = tp->snd_nxt;
 
        WARN_ON(packets > tp->packets_out);
        skb = tp->lost_skb_hint;
@@ -2218,26 +2216,11 @@ static void tcp_mark_head_lost(struct sock *sk, int packets, int mark_head)
                if (after(TCP_SKB_CB(skb)->end_seq, loss_high))
                        break;
 
-               oldcnt = cnt;
-               if (tcp_is_reno(tp) ||
-                   (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED))
+               if (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED)
                        cnt += tcp_skb_pcount(skb);
 
-               if (cnt > packets) {
-                       if (tcp_is_sack(tp) ||
-                           (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED) ||
-                           (oldcnt >= packets))
-                               break;
-
-                       mss = tcp_skb_mss(skb);
-                       /* If needed, chop off the prefix to mark as lost. */
-                       lost = (packets - oldcnt) * mss;
-                       if (lost < skb->len &&
-                           tcp_fragment(sk, TCP_FRAG_IN_RTX_QUEUE, skb,
-                                        lost, mss, GFP_ATOMIC) < 0)
-                               break;
-                       cnt = packets;
-               }
+               if (cnt > packets)
+                       break;
 
                tcp_skb_mark_lost(tp, skb);
 
@@ -2849,8 +2832,7 @@ static void tcp_fastretrans_alert(struct sock *sk, const u32 prior_snd_una,
                        if (tcp_try_undo_partial(sk, prior_snd_una))
                                return;
                        /* Partial ACK arrived. Force fast retransmit. */
-                       do_lost = tcp_is_reno(tp) ||
-                                 tcp_force_fast_retransmit(sk);
+                       do_lost = tcp_force_fast_retransmit(sk);
                }
                if (tcp_try_undo_dsack(sk)) {
                        tcp_try_keep_open(sk);