tcp: use this_cpu_read(*X) instead of *this_cpu_ptr(X)

this_cpu_read(*X) is slightly faster than *this_cpu_ptr(X)
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/tcp_ipv4.c

@@ -771,7 +771,7 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
 	arg.tos = ip_hdr(skb)->tos;
 	arg.uid = sock_net_uid(net, sk && sk_fullsock(sk) ? sk : NULL);
 	local_bh_disable();
-	ctl_sk = *this_cpu_ptr(net->ipv4.tcp_sk);
+	ctl_sk = this_cpu_read(*net->ipv4.tcp_sk);
 	if (sk)
 		ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ?
 				   inet_twsk(sk)->tw_mark : sk->sk_mark;
@@ -863,7 +863,7 @@ static void tcp_v4_send_ack(const struct sock *sk,
 	arg.tos = tos;
 	arg.uid = sock_net_uid(net, sk_fullsock(sk) ? sk : NULL);
 	local_bh_disable();
-	ctl_sk = *this_cpu_ptr(net->ipv4.tcp_sk);
+	ctl_sk = this_cpu_read(*net->ipv4.tcp_sk);
 	if (sk)
 		ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ?
 				   inet_twsk(sk)->tw_mark : sk->sk_mark;