Bluetooth: Add timeout for LE connection attempts

LE connection attempts do not have a controller side timeout in the same
way as BR/EDR has (in form of the page timeout). Since we always do
scanning before initiating connections the attempts are always expected
to succeed in some reasonable time.

This patch adds a timer which forces a cancellation of the connection
attempt within 20 seconds if it has not been successful by then. This
way we e.g. ensure that mgmt_pair_device times out eventually and gives
an error response.

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

net/bluetooth/hci_conn.c

@@ -363,6 +363,16 @@ static void hci_conn_auto_accept(struct work_struct *work)
 		     &conn->dst);
 }
 
+static void le_conn_timeout(struct work_struct *work)
+{
+	struct hci_conn *conn = container_of(work, struct hci_conn,
+					     le_conn_timeout.work);
+
+	BT_DBG("");
+
+	hci_le_create_connection_cancel(conn);
+}
+
 struct hci_conn *hci_conn_add(struct hci_dev *hdev, int type, bdaddr_t *dst)
 {
 	struct hci_conn *conn;
@@ -410,6 +420,7 @@ struct hci_conn *hci_conn_add(struct hci_dev *hdev, int type, bdaddr_t *dst)
 	INIT_DELAYED_WORK(&conn->disc_work, hci_conn_timeout);
 	INIT_DELAYED_WORK(&conn->auto_accept_work, hci_conn_auto_accept);
 	INIT_DELAYED_WORK(&conn->idle_work, hci_conn_idle);
+	INIT_DELAYED_WORK(&conn->le_conn_timeout, le_conn_timeout);
 
 	atomic_set(&conn->refcnt, 0);
 
@@ -442,6 +453,8 @@ int hci_conn_del(struct hci_conn *conn)
 		/* Unacked frames */
 		hdev->acl_cnt += conn->sent;
 	} else if (conn->type == LE_LINK) {
+		cancel_delayed_work_sync(&conn->le_conn_timeout);
+
 		if (hdev->le_pkts)
 			hdev->le_cnt += conn->sent;
 		else