mptcp: drop unneeded checks

After the previous patch subflow->conn is always != NULL and
is never changed. We can drop a bunch of now unneeded checks.

v1 -> v2:
 - rebased on top of commit 2398e399 ("mptcp: always
   include dack if possible.")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/mptcp/options.c

@@ -336,7 +336,6 @@ static bool mptcp_established_options_dss(struct sock *sk, struct sk_buff *skb,
 	unsigned int ack_size;
 	bool ret = false;
 	bool can_ack;
-	u64 ack_seq;
 	u8 tcp_fin;
 
 	if (skb) {
@@ -368,16 +367,7 @@ static bool mptcp_established_options_dss(struct sock *sk, struct sk_buff *skb,
 	can_ack = true;
 	opts->ext_copy.use_ack = 0;
 	msk = mptcp_sk(subflow->conn);
-	if (likely(msk && READ_ONCE(msk->can_ack))) {
-		ack_seq = msk->ack_seq;
-	} else if (subflow->can_ack) {
-		mptcp_crypto_key_sha(subflow->remote_key, NULL, &ack_seq);
-		ack_seq++;
-	} else {
-		can_ack = false;
-	}
-
-	if (unlikely(!can_ack)) {
+	if (!READ_ONCE(msk->can_ack)) {
 		*size = ALIGN(dss_size, 4);
 		return ret;
 	}
@@ -390,7 +380,7 @@ static bool mptcp_established_options_dss(struct sock *sk, struct sk_buff *skb,
 
 	dss_size += ack_size;
 
-	opts->ext_copy.data_ack = ack_seq;
+	opts->ext_copy.data_ack = msk->ack_seq;
 	opts->ext_copy.ack64 = 1;
 	opts->ext_copy.use_ack = 1;
 

net/mptcp/subflow.c

@@ -112,7 +112,7 @@ static void subflow_finish_connect(struct sock *sk, const struct sk_buff *skb)
 
 	subflow->icsk_af_ops->sk_rx_dst_set(sk, skb);
 
-	if (subflow->conn && !subflow->conn_finished) {
+	if (!subflow->conn_finished) {
 		pr_debug("subflow=%p, remote_key=%llu", mptcp_subflow_ctx(sk),
 			 subflow->remote_key);
 		mptcp_finish_connect(sk);
@@ -439,9 +439,6 @@ static bool subflow_check_data_avail(struct sock *ssk)
 	if (subflow->data_avail)
 		return true;
 
-	if (!subflow->conn)
-		return false;
-
 	msk = mptcp_sk(subflow->conn);
 	for (;;) {
 		u32 map_remaining;
@@ -561,11 +558,10 @@ static void subflow_data_ready(struct sock *sk)
 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
 	struct sock *parent = subflow->conn;
 
-	if (!parent || !subflow->mp_capable) {
+	if (!subflow->mp_capable) {
 		subflow->tcp_data_ready(sk);
 
-		if (parent)
-			parent->sk_data_ready(parent);
+		parent->sk_data_ready(parent);
 		return;
 	}
 
@@ -579,7 +575,7 @@ static void subflow_write_space(struct sock *sk)
 	struct sock *parent = subflow->conn;
 
 	sk_stream_write_space(sk);
-	if (parent && sk_stream_is_writeable(sk)) {
+	if (sk_stream_is_writeable(sk)) {
 		set_bit(MPTCP_SEND_SPACE, &mptcp_sk(parent)->flags);
 		smp_mb__after_atomic();
 		/* set SEND_SPACE before sk_stream_write_space clears NOSPACE */
@@ -694,7 +690,7 @@ static bool subflow_is_done(const struct sock *sk)
 static void subflow_state_change(struct sock *sk)
 {
 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
-	struct sock *parent = READ_ONCE(subflow->conn);
+	struct sock *parent = subflow->conn;
 
 	__subflow_state_change(sk);
 
@@ -702,10 +698,10 @@ static void subflow_state_change(struct sock *sk)
 	 * a fin packet carrying a DSS can be unnoticed if we don't trigger
 	 * the data available machinery here.
 	 */
-	if (parent && subflow->mp_capable && mptcp_subflow_data_available(sk))
+	if (subflow->mp_capable && mptcp_subflow_data_available(sk))
 		mptcp_data_ready(parent, sk);
 
-	if (parent && !(parent->sk_shutdown & RCV_SHUTDOWN) &&
+	if (!(parent->sk_shutdown & RCV_SHUTDOWN) &&
 	    !subflow->rx_eof && subflow_is_done(sk)) {
 		subflow->rx_eof = 1;
 		parent->sk_shutdown |= RCV_SHUTDOWN;