mptcp: add back mptcp_pm_subflow_closed

The MPTCP path manager event handler mptcp_pm_subflow_closed interface
is added in the commit "mptcp: Add path manager interface", but removed
in the commit "mptcp: do not block subflows creation on errors".

This patch adds it back and changes its 2nd parameter from "u8 id" to
"struct sock *ssk". Invoke mptcp_event with the MPTCP_EVENT_SUB_CLOSED
event type in it.

Signed-off-by: Geliang Tang <[email protected]>

Author: Geliang Tang

net/mptcp/pm.c

@@ -176,6 +176,13 @@ void mptcp_pm_subflow_established(struct mptcp_sock *msk)
 	spin_unlock_bh(&pm->lock);
 }
 
+void mptcp_pm_subflow_closed(struct mptcp_sock *msk, struct sock *ssk)
+{
+	pr_debug("msk=%p", msk);
+
+	mptcp_event(MPTCP_EVENT_SUB_CLOSED, msk, ssk, GFP_KERNEL);
+}
+
 void mptcp_pm_subflow_check_next(struct mptcp_sock *msk,
 				 const struct mptcp_subflow_context *subflow)
 {

net/mptcp/protocol.c

@@ -2515,7 +2515,7 @@ void mptcp_close_ssk(struct sock *sk, struct sock *ssk,
 	subflow->close_event_done = true;
 
 	if (sk->sk_state == TCP_ESTABLISHED)
-		mptcp_event(MPTCP_EVENT_SUB_CLOSED, mptcp_sk(sk), ssk, GFP_KERNEL);
+		mptcp_pm_subflow_closed(mptcp_sk(sk), ssk);
 
 	/* subflow aborted before reaching the fully_established status
 	 * attempt the creation of the next subflow

net/mptcp/protocol.h

@@ -996,6 +996,7 @@ void mptcp_pm_fully_established(struct mptcp_sock *msk, const struct sock *ssk);
 bool mptcp_pm_allow_new_subflow(struct mptcp_sock *msk);
 void mptcp_pm_connection_closed(struct mptcp_sock *msk);
 void mptcp_pm_subflow_established(struct mptcp_sock *msk);
+void mptcp_pm_subflow_closed(struct mptcp_sock *msk, struct sock *ssk);
 bool mptcp_pm_nl_check_work_pending(struct mptcp_sock *msk);
 void mptcp_pm_subflow_check_next(struct mptcp_sock *msk,
 				 const struct mptcp_subflow_context *subflow);