Bluetooth: Return ENETDOWN when interface is down

Sending commands to a down interface results in a timeout while clearly
it should just return ENETDOWN. When using the ioctls this works fine,
but not when using the HCI sockets sendmsg interface.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

net/bluetooth/hci_sock.c

@@ -414,6 +414,11 @@ static int hci_sock_sendmsg(struct kiocb *iocb, struct socket *sock,
 		goto done;
 	}
 
+	if (!test_bit(HCI_UP, &hdev->flags)) {
+		err = -ENETDOWN;
+		goto done;
+	}
+
 	if (!(skb = bt_skb_send_alloc(sk, len, msg->msg_flags & MSG_DONTWAIT, &err)))
 		goto done;