net: sock: do not set sk_cookie in sk_clone_lock()

The only call site of sk_clone_lock is in inet_csk_clone_lock,
and sk_cookie will be set there.
So we don't need to set sk_cookie in sk_clone_lock().
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/core/sock.c

@@ -1752,7 +1752,6 @@ struct sock *sk_clone_lock(const struct sock *sk, const gfp_t priority)
 		newsk->sk_err_soft = 0;
 		newsk->sk_priority = 0;
 		newsk->sk_incoming_cpu = raw_smp_processor_id();
-		atomic64_set(&newsk->sk_cookie, 0);
 		if (likely(newsk->sk_net_refcnt))
 			sock_inuse_add(sock_net(newsk), 1);