tcp: minor optimization around tcp_hdr() usage in receive path

This is additional to the
commit ea1627c20c34 ("tcp: minor optimizations around tcp_hdr() usage").
At this point, skb->data is same with tcp_hdr() as tcp header has not
been pulled yet. So use the less expensive one to get the tcp header.

Remove the third parameter of tcp_rcv_established() and put it into
the function body.

Furthermore, the local variables are listed as a reverse christmas tree :)

Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/tcp.h b/include/net/tcp.h
index 952d842..029a51b 100644 (file)
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -334,8 +334,7 @@ void tcp_write_timer_handler(struct sock *sk);
 void tcp_delack_timer_handler(struct sock *sk);
 int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg);
 int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb);
-void tcp_rcv_established(struct sock *sk, struct sk_buff *skb,
-                        const struct tcphdr *th);
+void tcp_rcv_established(struct sock *sk, struct sk_buff *skb);
 void tcp_rcv_space_adjust(struct sock *sk);
 int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp);
 void tcp_twsk_destructor(struct sock *sk);

diff --git a/include/trace/events/tcp.h b/include/trace/events/tcp.h
index 703abb6..ac55b32 100644 (file)
--- a/include/trace/events/tcp.h
+++ b/include/trace/events/tcp.h
@@ -248,8 +248,9 @@ TRACE_EVENT(tcp_probe,
        ),
 
        TP_fast_assign(
-               const struct tcp_sock *tp = tcp_sk(sk);
+               const struct tcphdr *th = (const struct tcphdr *)skb->data;
                const struct inet_sock *inet = inet_sk(sk);
+               const struct tcp_sock *tp = tcp_sk(sk);
 
                memset(__entry->saddr, 0, sizeof(struct sockaddr_in6));
                memset(__entry->daddr, 0, sizeof(struct sockaddr_in6));
@@ -261,7 +262,7 @@ TRACE_EVENT(tcp_probe,
                __entry->dport = ntohs(inet->inet_dport);
                __entry->mark = skb->mark;
 
-               __entry->data_len = skb->len - tcp_hdrlen(skb);
+               __entry->data_len = skb->len - __tcp_hdrlen(th);
                __entry->snd_nxt = tp->snd_nxt;
                __entry->snd_una = tp->snd_una;
                __entry->snd_cwnd = tp->snd_cwnd;

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 1191cac..d5ffb57 100644 (file)
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -5390,11 +5390,11 @@ discard:
  *     the rest is checked inline. Fast processing is turned on in
  *     tcp_data_queue when everything is OK.
  */
-void tcp_rcv_established(struct sock *sk, struct sk_buff *skb,
-                        const struct tcphdr *th)
+void tcp_rcv_established(struct sock *sk, struct sk_buff *skb)
 {
-       unsigned int len = skb->len;
+       const struct tcphdr *th = (const struct tcphdr *)skb->data;
        struct tcp_sock *tp = tcp_sk(sk);
+       unsigned int len = skb->len;
 
        /* TCP congestion window tracking */
        trace_tcp_probe(sk, skb);

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index adbdb50..749b0ef 100644 (file)
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1486,7 +1486,7 @@ int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
                                sk->sk_rx_dst = NULL;
                        }
                }
-               tcp_rcv_established(sk, skb, tcp_hdr(skb));
+               tcp_rcv_established(sk, skb);
                return 0;
        }
 

diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 7d47c2b..8764a63 100644 (file)
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1322,7 +1322,7 @@ static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
                        }
                }
 
-               tcp_rcv_established(sk, skb, tcp_hdr(skb));
+               tcp_rcv_established(sk, skb);
                if (opt_skb)
                        goto ipv6_pktoptions;
                return 0;