tcp: add helper for counter tweaking due mid-wq change

We need full-scale adjustment to fix a TCP miscount in the next
patch, so just move it into a helper and call for that from the
other places.

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

diff --git a/include/net/tcp.h b/include/net/tcp.h
index e54c76d..1b94b9b 100644 (file)
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -616,21 +616,6 @@ static inline int tcp_skb_mss(const struct sk_buff *skb)
        return skb_shinfo(skb)->gso_size;
 }
 
-static inline void tcp_dec_pcount_approx_int(__u32 *count, const int decr)
-{
-       if (*count) {
-               *count -= decr;
-               if ((int)*count < 0)
-                       *count = 0;
-       }
-}
-
-static inline void tcp_dec_pcount_approx(__u32 *count,
-                                        const struct sk_buff *skb)
-{
-       tcp_dec_pcount_approx_int(count, tcp_skb_pcount(skb));
-}
-
 /* Events passed to congestion control interface */
 enum tcp_ca_event {
        CA_EVENT_TX_START,      /* first transmit when no packets in flight */

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index c1f259d..f1db89b 100644 (file)
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -754,6 +754,36 @@ static void tcp_adjust_fackets_out(struct sock *sk, struct sk_buff *skb,
                tp->fackets_out -= decr;
 }
 
+/* Pcount in the middle of the write queue got changed, we need to do various
+ * tweaks to fix counters
+ */
+static void tcp_adjust_pcount(struct sock *sk, struct sk_buff *skb, int decr)
+{
+       struct tcp_sock *tp = tcp_sk(sk);
+
+       tp->packets_out -= decr;
+
+       if (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED)
+               tp->sacked_out -= decr;
+       if (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_RETRANS)
+               tp->retrans_out -= decr;
+       if (TCP_SKB_CB(skb)->sacked & TCPCB_LOST)
+               tp->lost_out -= decr;
+
+       /* Reno case is special. Sigh... */
+       if (tcp_is_reno(tp) && decr > 0)
+               tp->sacked_out -= min_t(u32, tp->sacked_out, decr);
+
+       tcp_adjust_fackets_out(sk, skb, decr);
+
+       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 -= decr;
+
+       tcp_verify_left_out(tp);
+}
+
 /* Function to create two new TCP segments.  Shrinks the given segment
  * to the specified size and appends a new segment with the rest of the
  * packet to the list.  This won't be called frequently, I hope.
@@ -836,28 +866,8 @@ int tcp_fragment(struct sock *sk, struct sk_buff *skb, u32 len,
                int diff = old_factor - tcp_skb_pcount(skb) -
                        tcp_skb_pcount(buff);
 
-               tp->packets_out -= diff;
-
-               if (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED)
-                       tp->sacked_out -= diff;
-               if (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_RETRANS)
-                       tp->retrans_out -= diff;
-
-               if (TCP_SKB_CB(skb)->sacked & TCPCB_LOST)
-                       tp->lost_out -= diff;
-
-               /* Adjust Reno SACK estimate. */
-               if (tcp_is_reno(tp) && diff > 0) {
-                       tcp_dec_pcount_approx_int(&tp->sacked_out, diff);
-                       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;
+               if (diff)
+                       tcp_adjust_pcount(sk, skb, diff);
        }
 
        /* Link BUFF into the send queue. */
@@ -1768,22 +1778,14 @@ static void tcp_collapse_retrans(struct sock *sk, struct sk_buff *skb)
         * packet counting does not break.
         */
        TCP_SKB_CB(skb)->sacked |= TCP_SKB_CB(next_skb)->sacked & TCPCB_EVER_RETRANS;
-       if (TCP_SKB_CB(next_skb)->sacked & TCPCB_SACKED_RETRANS)
-               tp->retrans_out -= tcp_skb_pcount(next_skb);
-       if (TCP_SKB_CB(next_skb)->sacked & TCPCB_LOST)
-               tp->lost_out -= tcp_skb_pcount(next_skb);
-       /* Reno case is special. Sigh... */
-       if (tcp_is_reno(tp) && tp->sacked_out)
-               tcp_dec_pcount_approx(&tp->sacked_out, next_skb);
-
-       tcp_adjust_fackets_out(sk, next_skb, tcp_skb_pcount(next_skb));
-       tp->packets_out -= tcp_skb_pcount(next_skb);
 
        /* changed transmit queue under us so clear hints */
        tcp_clear_retrans_hints_partial(tp);
        if (next_skb == tp->retransmit_skb_hint)
                tp->retransmit_skb_hint = skb;
 
+       tcp_adjust_pcount(sk, next_skb, tcp_skb_pcount(next_skb));
+
        sk_wmem_free_skb(sk, next_skb);
 }