media: cec-adap.c: add 'unregistered' checks

Make the code a bit more robust by checking if the adapter has
been unregistered at the start of cec_transmit_msg_fh() and
cec_received_msg_ts(). If it is unregistered, then just return.
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/media/cec/core/cec-adap.c

@@ -751,6 +751,9 @@ int cec_transmit_msg_fh(struct cec_adapter *adap, struct cec_msg *msg,
 	struct cec_data *data;
 	bool is_raw = msg_is_raw(msg);
 
+	if (adap->devnode.unregistered)
+		return -ENODEV;
+
 	msg->rx_ts = 0;
 	msg->tx_ts = 0;
 	msg->rx_status = 0;
@@ -1049,6 +1052,9 @@ void cec_received_msg_ts(struct cec_adapter *adap,
 	if (WARN_ON(!msg->len || msg->len > CEC_MAX_MSG_SIZE))
 		return;
 
+	if (adap->devnode.unregistered)
+		return;
+
 	/*
 	 * Some CEC adapters will receive the messages that they transmitted.
 	 * This test filters out those messages by checking if we are the