Increase pm subflows counter when userspace pm creates a new subflow,
and decrease the counter when it closes a subflow.

Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/329
Signed-off-by: Geliang Tang <geliang.tang@suse.com>
---
 net/mptcp/pm_userspace.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/mptcp/pm_userspace.c b/net/mptcp/pm_userspace.c
index a02d3cbf2a1b..36e10f6e434a 100644
--- a/net/mptcp/pm_userspace.c
+++ b/net/mptcp/pm_userspace.c
@@ -304,6 +304,7 @@ int mptcp_nl_cmd_sf_create(struct sk_buff *skb, struct genl_info *info)
 
 	lock_sock(sk);
 
+	msk->pm.subflows++;
 	err = __mptcp_subflow_connect(sk, &addr_l, &addr_r);
 
 	release_sock(sk);
@@ -424,6 +425,7 @@ int mptcp_nl_cmd_sf_destroy(struct sk_buff *skb, struct genl_info *info)
 		mptcp_subflow_shutdown(sk, ssk, RCV_SHUTDOWN | SEND_SHUTDOWN);
 		mptcp_close_ssk(sk, ssk, subflow);
 		MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RMSUBFLOW);
+		msk->pm.subflows--;
 		err = 0;
 	} else {
 		err = -ESRCH;
-- 
2.35.3