After the previous patch the first subflow is allocated as
needed at bind, connect, listen time. We don't need anymore
to keep alive the first subflow after a disconnect just to
be able to perform such syscall.

Overal this change makes the passive and active sockets consistent:
even passive sockets will be allowed to complete life cycle after
disconnect.

Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/290
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---
 net/mptcp/protocol.c | 24 +++++-------------------
 1 file changed, 5 insertions(+), 19 deletions(-)

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 4f7a71561efd..b867e3eec5b9 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -2371,11 +2371,9 @@ static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
 			      unsigned int flags)
 {
 	struct mptcp_sock *msk = mptcp_sk(sk);
-	bool need_push, dispose_it;
+	bool need_push;
 
-	dispose_it = !msk->subflow || ssk != msk->subflow->sk;
-	if (dispose_it)
-		list_del(&subflow->node);
+	list_del(&subflow->node);
 
 	lock_sock_nested(ssk, SINGLE_DEPTH_NESTING);
 
@@ -2389,15 +2387,6 @@ static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
 	}
 
 	need_push = (flags & MPTCP_CF_PUSH) && __mptcp_retransmit_pending_data(sk);
-	if (!dispose_it) {
-		tcp_disconnect(ssk, 0);
-		msk->subflow->state = SS_UNCONNECTED;
-		mptcp_subflow_ctx_reset(subflow);
-		release_sock(ssk);
-
-		goto out;
-	}
-
 	sock_orphan(ssk);
 	subflow->disposable = 1;
 
@@ -2424,10 +2413,11 @@ static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
 
 	sock_put(ssk);
 
-	if (ssk == msk->first)
+	if (ssk == msk->first) {
 		msk->first = NULL;
+		mptcp_dispose_initial_subflow(msk);
+	}
 
-out:
 	if (ssk == msk->last_snd)
 		msk->last_snd = NULL;
 
@@ -3270,10 +3260,6 @@ static void mptcp_destroy(struct sock *sk)
 {
 	struct mptcp_sock *msk = mptcp_sk(sk);
 
-	/* clears msk->subflow, allowing the following to close
-	 * even the initial subflow
-	 */
-	mptcp_dispose_initial_subflow(msk);
 	mptcp_destroy_common(msk, 0);
 	sk_sockets_allocated_dec(sk);
 }
-- 
2.39.0