Merge git://git.infradead.org/hdrcleanup-2.6

[linux-2.6] / net / ipv4 / tcp_output.c

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 743016baa04867473a022008367aa05a61bac284..07bb5a2b375ec0b02e1be3774a474fbeae24a808 100644 (file)
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -59,6 +59,9 @@ int sysctl_tcp_tso_win_divisor = 3;
 int sysctl_tcp_mtu_probing = 0;
 int sysctl_tcp_base_mss = 512;
 
+/* By default, RFC2861 behavior.  */
+int sysctl_tcp_slow_start_after_idle = 1;
+
 static void update_send_head(struct sock *sk, struct tcp_sock *tp,
                             struct sk_buff *skb)
 {
@@ -138,7 +141,8 @@ static void tcp_event_data_sent(struct tcp_sock *tp,
        struct inet_connection_sock *icsk = inet_csk(sk);
        const u32 now = tcp_time_stamp;
 
-       if (!tp->packets_out && (s32)(now - tp->lsndtime) > icsk->icsk_rto)
+       if (sysctl_tcp_slow_start_after_idle &&
+           (!tp->packets_out && (s32)(now - tp->lsndtime) > icsk->icsk_rto))
                tcp_cwnd_restart(sk, __sk_dst_get(sk));
 
        tp->lsndtime = now;
@@ -642,7 +646,7 @@ int tcp_fragment(struct sock *sk, struct sk_buff *skb, u32 len, unsigned int mss
  * eventually). The difference is that pulled data not copied, but
  * immediately discarded.
  */
-static unsigned char *__pskb_trim_head(struct sk_buff *skb, int len)
+static void __pskb_trim_head(struct sk_buff *skb, int len)
 {
        int i, k, eat;
 
@@ -667,7 +671,6 @@ static unsigned char *__pskb_trim_head(struct sk_buff *skb, int len)
        skb->tail = skb->data;
        skb->data_len -= len;
        skb->len = skb->data_len;
-       return skb->tail;
 }
 
 int tcp_trim_head(struct sock *sk, struct sk_buff *skb, u32 len)
@@ -676,12 +679,11 @@ int tcp_trim_head(struct sock *sk, struct sk_buff *skb, u32 len)
            pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
                return -ENOMEM;
 
-       if (len <= skb_headlen(skb)) {
+       /* If len == headlen, we avoid __skb_pull to preserve alignment. */
+       if (unlikely(len < skb_headlen(skb)))
                __skb_pull(skb, len);
-       } else {
-               if (__pskb_trim_head(skb, len-skb_headlen(skb)) == NULL)
-                       return -ENOMEM;
-       }
+       else
+               __pskb_trim_head(skb, len - skb_headlen(skb));
 
        TCP_SKB_CB(skb)->seq += len;
        skb->ip_summed = CHECKSUM_HW;