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>

1 files changed, 3 insertions, 2 deletions

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index b7c2f439b54f..eace049da052 100644
--- 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;