mptcp: unify RM_ADDR and RM_SUBFLOW receiving

There are some duplicate code in mptcp_pm_nl_rm_addr_received and
mptcp_pm_nl_rm_subflow_received. This patch unifies them into a new
function named mptcp_pm_nl_rm_addr_or_subflow. In it, use the input
parameter rm_type to identify it's now removing an address or a subflow.
Suggested-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Geliang Tang <geliangtang@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/mptcp/pm_netlink.c

@@ -586,45 +586,68 @@ int mptcp_pm_nl_mp_prio_send_ack(struct mptcp_sock *msk,
 	return -EINVAL;
 }
 
-static void mptcp_pm_nl_rm_addr_received(struct mptcp_sock *msk)
+static void mptcp_pm_nl_rm_addr_or_subflow(struct mptcp_sock *msk,
+					   const struct mptcp_rm_list *rm_list,
+					   enum linux_mptcp_mib_field rm_type)
 {
 	struct mptcp_subflow_context *subflow, *tmp;
 	struct sock *sk = (struct sock *)msk;
 	u8 i;
 
-	pr_debug("address rm_list_nr %d", msk->pm.rm_list_rx.nr);
+	pr_debug("%s rm_list_nr %d",
+		 rm_type == MPTCP_MIB_RMADDR ? "address" : "subflow", rm_list->nr);
 
 	msk_owned_by_me(msk);
 
-	if (!msk->pm.rm_list_rx.nr)
+	if (!rm_list->nr)
 		return;
 
 	if (list_empty(&msk->conn_list))
 		return;
 
-	for (i = 0; i < msk->pm.rm_list_rx.nr; i++) {
+	for (i = 0; i < rm_list->nr; i++) {
 		list_for_each_entry_safe(subflow, tmp, &msk->conn_list, node) {
 			struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
 			int how = RCV_SHUTDOWN | SEND_SHUTDOWN;
+			u8 id = subflow->local_id;
+
+			if (rm_type == MPTCP_MIB_RMADDR)
+				id = subflow->remote_id;
 
-			if (msk->pm.rm_list_rx.ids[i] != subflow->remote_id)
+			if (rm_list->ids[i] != id)
 				continue;
 
-			pr_debug(" -> address rm_list_ids[%d]=%u", i, msk->pm.rm_list_rx.ids[i]);
+			pr_debug(" -> %s rm_list_ids[%d]=%u local_id=%u remote_id=%u",
+				 rm_type == MPTCP_MIB_RMADDR ? "address" : "subflow",
+				 i, rm_list->ids[i], subflow->local_id, subflow->remote_id);
 			spin_unlock_bh(&msk->pm.lock);
 			mptcp_subflow_shutdown(sk, ssk, how);
 			mptcp_close_ssk(sk, ssk, subflow);
 			spin_lock_bh(&msk->pm.lock);
 
+			if (rm_type == MPTCP_MIB_RMADDR) {
 				msk->pm.add_addr_accepted--;
-			msk->pm.subflows--;
 				WRITE_ONCE(msk->pm.accept_addr, true);
-
-			__MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RMADDR);
+			} else if (rm_type == MPTCP_MIB_RMSUBFLOW) {
+				msk->pm.local_addr_used--;
+			}
+			msk->pm.subflows--;
+			__MPTCP_INC_STATS(sock_net(sk), rm_type);
 		}
 	}
 }
 
+static void mptcp_pm_nl_rm_addr_received(struct mptcp_sock *msk)
+{
+	mptcp_pm_nl_rm_addr_or_subflow(msk, &msk->pm.rm_list_rx, MPTCP_MIB_RMADDR);
+}
+
+void mptcp_pm_nl_rm_subflow_received(struct mptcp_sock *msk,
+				     const struct mptcp_rm_list *rm_list)
+{
+	mptcp_pm_nl_rm_addr_or_subflow(msk, rm_list, MPTCP_MIB_RMSUBFLOW);
+}
+
 void mptcp_pm_nl_work(struct mptcp_sock *msk)
 {
 	struct mptcp_pm_data *pm = &msk->pm;
@@ -658,45 +681,6 @@ void mptcp_pm_nl_work(struct mptcp_sock *msk)
 	spin_unlock_bh(&msk->pm.lock);
 }
 
-void mptcp_pm_nl_rm_subflow_received(struct mptcp_sock *msk,
-				     const struct mptcp_rm_list *rm_list)
-{
-	struct mptcp_subflow_context *subflow, *tmp;
-	struct sock *sk = (struct sock *)msk;
-	u8 i;
-
-	pr_debug("subflow rm_list_nr %d", rm_list->nr);
-
-	msk_owned_by_me(msk);
-
-	if (!rm_list->nr)
-		return;
-
-	if (list_empty(&msk->conn_list))
-		return;
-
-	for (i = 0; i < rm_list->nr; i++) {
-		list_for_each_entry_safe(subflow, tmp, &msk->conn_list, node) {
-			struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
-			int how = RCV_SHUTDOWN | SEND_SHUTDOWN;
-
-			if (rm_list->ids[i] != subflow->local_id)
-				continue;
-
-			pr_debug(" -> subflow rm_list_ids[%d]=%u", i, rm_list->ids[i]);
-			spin_unlock_bh(&msk->pm.lock);
-			mptcp_subflow_shutdown(sk, ssk, how);
-			mptcp_close_ssk(sk, ssk, subflow);
-			spin_lock_bh(&msk->pm.lock);
-
-			msk->pm.local_addr_used--;
-			msk->pm.subflows--;
-
-			__MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RMSUBFLOW);
-		}
-	}
-}
-
 static bool address_use_port(struct mptcp_pm_addr_entry *entry)
 {
 	return (entry->addr.flags &