net: fix CONFIG_NET_NS=n compilation

I forgot to use write_pnet() in three locations.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Fixes: 33cf7c90fe2f9 ("net: add real socket cookies")
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/dccp/ipv4.c

@@ -641,7 +641,7 @@ int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
 	ireq = inet_rsk(req);
 	ireq->ir_loc_addr = ip_hdr(skb)->daddr;
 	ireq->ir_rmt_addr = ip_hdr(skb)->saddr;
-	ireq->ireq_net = sock_net(sk);
+	write_pnet(&ireq->ireq_net, sock_net(sk));
 	atomic64_set(&ireq->ir_cookie, 0);
 
 	/*

net/ipv4/syncookies.c

@@ -346,7 +346,7 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb)
 	req->ts_recent		= tcp_opt.saw_tstamp ? tcp_opt.rcv_tsval : 0;
 	treq->snt_synack	= tcp_opt.saw_tstamp ? tcp_opt.rcv_tsecr : 0;
 	treq->listener		= NULL;
-	ireq->ireq_net		= sock_net(sk);
+	write_pnet(&ireq->ireq_net, sock_net(sk));
 
 	/* We throwed the options of the initial SYN away, so we hope
 	 * the ACK carries the same options again (see RFC1122 4.2.3.8)

net/ipv4/tcp_input.c

@@ -5965,7 +5965,7 @@ int tcp_conn_request(struct request_sock_ops *rsk_ops,
 
 	tmp_opt.tstamp_ok = tmp_opt.saw_tstamp;
 	tcp_openreq_init(req, &tmp_opt, skb, sk);
-	inet_rsk(req)->ireq_net = sock_net(sk);
+	write_pnet(&inet_rsk(req)->ireq_net, sock_net(sk));
 	atomic64_set(&inet_rsk(req)->ir_cookie, 0);
 
 	af_ops->init_req(req, sk, skb);