[PATCH 5.10.y] mptcp: fix NL PM announced address accounting

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

From: Paolo Abeni <pabeni@redhat.com>

commit 4b317e0eb287bd30a1b329513531157c25e8b692 upstream.

Currently the per connection announced address counter is never
decreased. As a consequence, after connection establishment, if
the NL PM deletes an endpoint and adds a new/different one, no
additional subflow is created for the new endpoint even if the
current limits allow that.

Address the issue properly updating the signaled address counter
every time the NL PM removes such addresses.

Fixes: 01cacb00b35c ("mptcp: add netlink-based PM")
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
[ Conflicts in pm_netlink.c, because the commit 06faa2271034 ("mptcp:
  remove multi addresses and subflows in PM") is not in this version.
  Only the modification in mptcp_pm_remove_anno_addr() is then needed. ]
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
 net/mptcp/pm_netlink.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index 452c7e21befd..7f4d84f5189b 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -759,6 +759,7 @@ static bool mptcp_pm_remove_anno_addr(struct mptcp_sock *msk,
 	ret = remove_anno_list_by_saddr(msk, addr);
 	if (ret || force) {
 		spin_lock_bh(&msk->pm.lock);
+		msk->pm.add_addr_signaled -= ret;
 		mptcp_pm_remove_addr(msk, addr->id);
 		spin_unlock_bh(&msk->pm.lock);
 	}
-- 
2.45.2