[PATCH 5.15.y] mptcp: pm: do not remove already closed subflows

["Matthieu Baerts (NGI0)" <matttbe@kernel.org>]

commit 58e1b66b4e4b8a602d3f2843e8eba00a969ecce2 upstream.

It is possible to have in the list already closed subflows, e.g. the
initial subflow has been already closed, but still in the list. No need
to try to close it again, and increments the related counters again.

Fixes: 0ee4261a3681 ("mptcp: implement mptcp_pm_remove_subflow")
Cc: stable@vger.kernel.org
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
[ Conflicts in pm_netlink.c, due to commit 3ad14f54bd74 ("mptcp: more
  accurate MPC endpoint tracking") which is not in this version, and
  changes the context. The same fix can be applied here by adding the
  new check at the same place. ]
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
 net/mptcp/pm_netlink.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index c77e596c477c..6df7d62f6b44 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -763,6 +763,9 @@ static void mptcp_pm_nl_rm_addr_or_subflow(struct mptcp_sock *msk,
 			int how = RCV_SHUTDOWN | SEND_SHUTDOWN;
 			u8 id = subflow->local_id;
 
+			if (inet_sk_state_load(ssk) == TCP_CLOSE)
+				continue;
+
 			if (rm_type == MPTCP_MIB_RMADDR)
 				id = subflow->remote_id;
 
-- 
2.45.2