[TCP]: tcp_rcv_rtt_measure_ts() call in pure-ACK path is superfluous

[linux-2.6-omap-h63xx.git] / net / ipv4 / tcp_input.c

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index b5521a9d3dc1a3acbbbf35ca50b8425fb0f882ca..6d167889a4b06991becca0a99d0e4d6550bb9be0 100644 (file)
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -71,6 +71,7 @@
 #include <net/inet_common.h>
 #include <linux/ipsec.h>
 #include <asm/unaligned.h>
+#include <net/netdma.h>
 
 int sysctl_tcp_timestamps = 1;
 int sysctl_tcp_window_scaling = 1;
@@ -3785,6 +3786,50 @@ static inline int tcp_checksum_complete_user(struct sock *sk, struct sk_buff *sk
                __tcp_checksum_complete_user(sk, skb);
 }
 
+#ifdef CONFIG_NET_DMA
+static int tcp_dma_try_early_copy(struct sock *sk, struct sk_buff *skb, int hlen)
+{
+       struct tcp_sock *tp = tcp_sk(sk);
+       int chunk = skb->len - hlen;
+       int dma_cookie;
+       int copied_early = 0;
+
+       if (tp->ucopy.wakeup)
+               return 0;
+
+       if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
+               tp->ucopy.dma_chan = get_softnet_dma();
+
+       if (tp->ucopy.dma_chan && skb->ip_summed == CHECKSUM_UNNECESSARY) {
+
+               dma_cookie = dma_skb_copy_datagram_iovec(tp->ucopy.dma_chan,
+                       skb, hlen, tp->ucopy.iov, chunk, tp->ucopy.pinned_list);
+
+               if (dma_cookie < 0)
+                       goto out;
+
+               tp->ucopy.dma_cookie = dma_cookie;
+               copied_early = 1;
+
+               tp->ucopy.len -= chunk;
+               tp->copied_seq += chunk;
+               tcp_rcv_space_adjust(sk);
+
+               if ((tp->ucopy.len == 0) ||
+                   (tcp_flag_word(skb->h.th) & TCP_FLAG_PSH) ||
+                   (atomic_read(&sk->sk_rmem_alloc) > (sk->sk_rcvbuf >> 1))) {
+                       tp->ucopy.wakeup = 1;
+                       sk->sk_data_ready(sk, 0);
+               }
+       } else if (chunk > 0) {
+               tp->ucopy.wakeup = 1;
+               sk->sk_data_ready(sk, 0);
+       }
+out:
+       return copied_early;
+}
+#endif /* CONFIG_NET_DMA */
+
 /*
  *     TCP receive function for the ESTABLISHED state. 
  *
@@ -3886,8 +3931,6 @@ int tcp_rcv_established(struct sock *sk, struct sk_buff *skb,
                                    tp->rcv_nxt == tp->rcv_wup)
                                        tcp_store_ts_recent(tp);
 
-                               tcp_rcv_rtt_measure_ts(sk, skb);
-
                                /* We know that such packets are checksummed
                                 * on entry.
                                 */
@@ -3901,14 +3944,23 @@ int tcp_rcv_established(struct sock *sk, struct sk_buff *skb,
                        }
                } else {
                        int eaten = 0;
+                       int copied_early = 0;
 
-                       if (tp->ucopy.task == current &&
-                           tp->copied_seq == tp->rcv_nxt &&
-                           len - tcp_header_len <= tp->ucopy.len &&
-                           sock_owned_by_user(sk)) {
-                               __set_current_state(TASK_RUNNING);
+                       if (tp->copied_seq == tp->rcv_nxt &&
+                           len - tcp_header_len <= tp->ucopy.len) {
+#ifdef CONFIG_NET_DMA
+                               if (tcp_dma_try_early_copy(sk, skb, tcp_header_len)) {
+                                       copied_early = 1;
+                                       eaten = 1;
+                               }
+#endif
+                               if (tp->ucopy.task == current && sock_owned_by_user(sk) && !copied_early) {
+                                       __set_current_state(TASK_RUNNING);
 
-                               if (!tcp_copy_to_iovec(sk, skb, tcp_header_len)) {
+                                       if (!tcp_copy_to_iovec(sk, skb, tcp_header_len))
+                                               eaten = 1;
+                               }
+                               if (eaten) {
                                        /* Predicted packet is in window by definition.
                                         * seq == rcv_nxt and rcv_wup <= rcv_nxt.
                                         * Hence, check seq<=rcv_wup reduces to:
@@ -3924,8 +3976,9 @@ int tcp_rcv_established(struct sock *sk, struct sk_buff *skb,
                                        __skb_pull(skb, tcp_header_len);
                                        tp->rcv_nxt = TCP_SKB_CB(skb)->end_seq;
                                        NET_INC_STATS_BH(LINUX_MIB_TCPHPHITSTOUSER);
-                                       eaten = 1;
                                }
+                               if (copied_early)
+                                       tcp_cleanup_rbuf(sk, skb->len);
                        }
                        if (!eaten) {
                                if (tcp_checksum_complete_user(sk, skb))
@@ -3966,6 +4019,11 @@ int tcp_rcv_established(struct sock *sk, struct sk_buff *skb,
 
                        __tcp_ack_snd_check(sk, 0);
 no_ack:
+#ifdef CONFIG_NET_DMA
+                       if (copied_early)
+                               __skb_queue_tail(&sk->sk_async_wait_queue, skb);
+                       else
+#endif
                        if (eaten)
                                __kfree_skb(skb);
                        else