tcp: set TCP_KEEPCNT locklessly

tp->keepalive_probes can be set locklessly, readers
are already taking care of this field being potentially
set by other threads.

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

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 75d6359..e74a959 100644 (file)
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -3358,10 +3358,8 @@ int tcp_sock_set_keepcnt(struct sock *sk, int val)
        if (val < 1 || val > MAX_TCP_KEEPCNT)
                return -EINVAL;
 
-       lock_sock(sk);
        /* Paired with READ_ONCE() in keepalive_probes() */
        WRITE_ONCE(tcp_sk(sk)->keepalive_probes, val);
-       release_sock(sk);
        return 0;
 }
 EXPORT_SYMBOL(tcp_sock_set_keepcnt);
@@ -3471,6 +3469,8 @@ int do_tcp_setsockopt(struct sock *sk, int level, int optname,
                return tcp_sock_set_user_timeout(sk, val);
        case TCP_KEEPINTVL:
                return tcp_sock_set_keepintvl(sk, val);
+       case TCP_KEEPCNT:
+               return tcp_sock_set_keepcnt(sk, val);
        }
 
        sockopt_lock_sock(sk);
@@ -3568,12 +3568,6 @@ int do_tcp_setsockopt(struct sock *sk, int level, int optname,
        case TCP_KEEPIDLE:
                err = tcp_sock_set_keepidle_locked(sk, val);
                break;
-       case TCP_KEEPCNT:
-               if (val < 1 || val > MAX_TCP_KEEPCNT)
-                       err = -EINVAL;
-               else
-                       WRITE_ONCE(tp->keepalive_probes, val);
-               break;
        case TCP_SAVE_SYN:
                /* 0: disable, 1: enable, 2: start from ether_header */
                if (val < 0 || val > 2)