tcp: refactor tcp_ecn_check_ce to remove sk type cast

Refactor tcp_ecn_check_ce and __tcp_ecn_check_ce to accept struct sock*
instead of tcp_sock* to clean up type casts. This is a pure refactor
patch.

Signed-off-by: Yousuk Seung <ysseung@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Yuchung Cheng <ycheng@google.com>
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>

net/ipv4/tcp_input.c

@@ -254,8 +254,10 @@ static void tcp_ecn_withdraw_cwr(struct tcp_sock *tp)
 	tp->ecn_flags &= ~TCP_ECN_DEMAND_CWR;
 }
 
-static void __tcp_ecn_check_ce(struct tcp_sock *tp, const struct sk_buff *skb)
+static void __tcp_ecn_check_ce(struct sock *sk, const struct sk_buff *skb)
 {
+	struct tcp_sock *tp = tcp_sk(sk);
+
 	switch (TCP_SKB_CB(skb)->ip_dsfield & INET_ECN_MASK) {
 	case INET_ECN_NOT_ECT:
 		/* Funny extension: if ECT is not set on a segment,
@@ -263,31 +265,31 @@ static void __tcp_ecn_check_ce(struct tcp_sock *tp, const struct sk_buff *skb)
 		 * it is probably a retransmit.
 		 */
 		if (tp->ecn_flags & TCP_ECN_SEEN)
-			tcp_enter_quickack_mode((struct sock *)tp, 1);
+			tcp_enter_quickack_mode(sk, 1);
 		break;
 	case INET_ECN_CE:
-		if (tcp_ca_needs_ecn((struct sock *)tp))
-			tcp_ca_event((struct sock *)tp, CA_EVENT_ECN_IS_CE);
+		if (tcp_ca_needs_ecn(sk))
+			tcp_ca_event(sk, CA_EVENT_ECN_IS_CE);
 
 		if (!(tp->ecn_flags & TCP_ECN_DEMAND_CWR)) {
 			/* Better not delay acks, sender can have a very low cwnd */
-			tcp_enter_quickack_mode((struct sock *)tp, 1);
+			tcp_enter_quickack_mode(sk, 1);
 			tp->ecn_flags |= TCP_ECN_DEMAND_CWR;
 		}
 		tp->ecn_flags |= TCP_ECN_SEEN;
 		break;
 	default:
-		if (tcp_ca_needs_ecn((struct sock *)tp))
-			tcp_ca_event((struct sock *)tp, CA_EVENT_ECN_NO_CE);
+		if (tcp_ca_needs_ecn(sk))
+			tcp_ca_event(sk, CA_EVENT_ECN_NO_CE);
 		tp->ecn_flags |= TCP_ECN_SEEN;
 		break;
 	}
 }
 
-static void tcp_ecn_check_ce(struct tcp_sock *tp, const struct sk_buff *skb)
+static void tcp_ecn_check_ce(struct sock *sk, const struct sk_buff *skb)
 {
-	if (tp->ecn_flags & TCP_ECN_OK)
-		__tcp_ecn_check_ce(tp, skb);
+	if (tcp_sk(sk)->ecn_flags & TCP_ECN_OK)
+		__tcp_ecn_check_ce(sk, skb);
 }
 
 static void tcp_ecn_rcv_synack(struct tcp_sock *tp, const struct tcphdr *th)
@@ -710,7 +712,7 @@ static void tcp_event_data_recv(struct sock *sk, struct sk_buff *skb)
 	}
 	icsk->icsk_ack.lrcvtime = now;
 
-	tcp_ecn_check_ce(tp, skb);
+	tcp_ecn_check_ce(sk, skb);
 
 	if (skb->len >= 128)
 		tcp_grow_window(sk, skb);
@@ -4434,7 +4436,7 @@ static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb)
 	u32 seq, end_seq;
 	bool fragstolen;
 
-	tcp_ecn_check_ce(tp, skb);
+	tcp_ecn_check_ce(sk, skb);
 
 	if (unlikely(tcp_try_rmem_schedule(sk, skb, skb->truesize))) {
 		NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPOFODROP);