mptcp: cleanup state propagation.

When propagating the first subflow state via the release_cb, the
msk must actually take to 2 separate actions: state sync-up and
send buffer sync-up. Relaying on the specific flags instead of
bounding both in __mptcp_sync_state(), allows cleaning up a bit
the code.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Message-Id: <240a97d522887a938faeb24a6a3e3a9ed24570b1.1700667908.git.pabeni@redhat.com>

net/mptcp/protocol.c

@@ -3404,9 +3404,8 @@ static void mptcp_release_cb(struct sock *sk)
 	if (unlikely(msk->cb_flags)) {
 		/* be sure to sync the msk state before taking actions
 		 * depending on sk_state (MPTCP_ERROR_REPORT)
-		 * On sk release avoid actions depending on the first subflow
 		 */
-		if (__test_and_clear_bit(MPTCP_SYNC_STATE, &msk->cb_flags) && msk->first)
+		if (__test_and_clear_bit(MPTCP_SYNC_STATE, &msk->cb_flags))
 			__mptcp_sync_state(sk, msk->pending_state);
 		if (__test_and_clear_bit(MPTCP_ERROR_REPORT, &msk->cb_flags))
 			__mptcp_error_report(sk);

net/mptcp/subflow.c

@@ -421,9 +421,6 @@ static bool subflow_use_different_dport(struct mptcp_sock *msk, const struct soc
 
 void __mptcp_sync_state(struct sock *sk, int state)
 {
-	struct mptcp_sock *msk = mptcp_sk(sk);
-
-	__mptcp_propagate_sndbuf(sk, msk->first);
 	if (sk->sk_state == TCP_SYN_SENT) {
 		inet_sk_state_store(sk, state);
 		sk->sk_state_change(sk);
@@ -436,10 +433,12 @@ static void mptcp_propagate_state(struct sock *sk, struct sock *ssk)
 
 	mptcp_data_lock(sk);
 	if (!sock_owned_by_user(sk)) {
+		__mptcp_propagate_sndbuf(sk, msk->first);
 		__mptcp_sync_state(sk, ssk->sk_state);
 	} else {
 		msk->pending_state = ssk->sk_state;
 		__set_bit(MPTCP_SYNC_STATE, &msk->cb_flags);
+		__set_bit(MPTCP_SYNC_SNDBUF, &msk->cb_flags);
 	}
 	mptcp_data_unlock(sk);
 }