Bluetooth: Fix hci_conn reference counting with hci_chan

The hci_chan_del() function was doing a hci_conn_drop() but there was no
matching hci_conn_hold() in the hci_chan_create() function. Furthermore,
as the hci_chan struct holds a pointer to the hci_conn there should be
proper use of hci_conn_get/put. This patch fixes both issues so that
hci_chan does correct reference counting of the hci_conn object.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

net/bluetooth/hci_conn.c

@@ -1295,7 +1295,8 @@ struct hci_chan *hci_chan_create(struct hci_conn *conn)
 	if (!chan)
 		return NULL;
 
-	chan->conn = conn;
+	chan->conn = hci_conn_get(conn);
+	hci_conn_hold(conn);
 	skb_queue_head_init(&chan->data_q);
 	chan->state = BT_CONNECTED;
 
@@ -1316,6 +1317,7 @@ void hci_chan_del(struct hci_chan *chan)
 	synchronize_rcu();
 
 	hci_conn_drop(conn);
+	hci_conn_put(conn);
 
 	skb_queue_purge(&chan->data_q);
 	kfree(chan);