Bluetooth: Lookup channel structure based on DCID

Processing a move channel request involves getting the channel
structure using the destination channel ID.  Previous code could only
look up using the source channel ID.

Signed-off-by: Mat Martineau <mathewm@codeaurora.org>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Acked-by: Andrei Emeltchenko <andrei.emeltchenko@intel.com>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>

net/bluetooth/l2cap_core.c

@@ -100,6 +100,23 @@ static struct l2cap_chan *l2cap_get_chan_by_scid(struct l2cap_conn *conn,
 	return c;
 }
 
+/* Find channel with given DCID.
+ * Returns locked channel.
+ */
+static struct l2cap_chan *l2cap_get_chan_by_dcid(struct l2cap_conn *conn,
+						 u16 cid)
+{
+	struct l2cap_chan *c;
+
+	mutex_lock(&conn->chan_lock);
+	c = __l2cap_get_chan_by_dcid(conn, cid);
+	if (c)
+		l2cap_chan_lock(c);
+	mutex_unlock(&conn->chan_lock);
+
+	return c;
+}
+
 static struct l2cap_chan *__l2cap_get_chan_by_ident(struct l2cap_conn *conn,
 						    u8 ident)
 {