tcp: speedup SIOCINQ ioctl

SIOCINQ can use the lock_sock_fast() version to avoid double acquisition
of socket lock.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index b7c2f439b54f92a9f9b036dccbc56206c4a6d53c..eace049da052befb0adf86c483b46fc8683e5419 100644 (file)
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -536,13 +536,14 @@ int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
 {
        struct tcp_sock *tp = tcp_sk(sk);
        int answ;
+       bool slow;
 
        switch (cmd) {
        case SIOCINQ:
                if (sk->sk_state == TCP_LISTEN)
                        return -EINVAL;
 
-               lock_sock(sk);
+               slow = lock_sock_fast(sk);
                if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
                        answ = 0;
                else if (sock_flag(sk, SOCK_URGINLINE) ||
@@ -557,7 +558,7 @@ int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
                                answ--;
                } else
                        answ = tp->urg_seq - tp->copied_seq;
-               release_sock(sk);
+               unlock_sock_fast(sk, slow);
                break;
        case SIOCATMARK:
                answ = tp->urg_data && tp->urg_seq == tp->copied_seq;