Bluetooth: SCO: fix sco_conn refcounting on sco_conn_ready

sco_conn refcount shall not be incremented a second time if the sk
already owns the refcount, so hold only when adding new chan.

Add sco_conn_hold() for clarity, as refcnt is never zero here due to the
sco_conn_add().

Fixes SCO socket shutdown not actually closing the SCO connection.

Fixes: ed95885 ("Bluetooth: SCO: remove the redundant sco_conn_put")
Signed-off-by: Pauli Virtanen <pav@iki.fi>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

Author: pv

net/bluetooth/sco.c

@@ -107,6 +107,14 @@ static void sco_conn_put(struct sco_conn *conn)
 	kref_put(&conn->ref, sco_conn_free);
 }
 
+static struct sco_conn *sco_conn_hold(struct sco_conn *conn)
+{
+	BT_DBG("conn %p refcnt %u", conn, kref_read(&conn->ref));
+
+	kref_get(&conn->ref);
+	return conn;
+}
+
 static struct sco_conn *sco_conn_hold_unless_zero(struct sco_conn *conn)
 {
 	if (!conn)
@@ -1353,6 +1361,7 @@ static void sco_conn_ready(struct sco_conn *conn)
 		bacpy(&sco_pi(sk)->src, &conn->hcon->src);
 		bacpy(&sco_pi(sk)->dst, &conn->hcon->dst);
 
+		sco_conn_hold(conn);
 		hci_conn_hold(conn->hcon);
 		__sco_chan_add(conn, sk, parent);
 
@@ -1411,8 +1420,10 @@ static void sco_connect_cfm(struct hci_conn *hcon, __u8 status)
 		struct sco_conn *conn;
 
 		conn = sco_conn_add(hcon);
-		if (conn)
+		if (conn) {
 			sco_conn_ready(conn);
+			sco_conn_put(conn);
+		}
 	} else
 		sco_conn_del(hcon, bt_to_errno(status));
 }