rpmsg: glink: Remove the rpmsg dev in close_ack

Un-register and register of rpmsg driver is sending invalid open_ack
on closed channel.

To avoid sending invalid open_ack case unregister the rpmsg device
after receiving the local_close_ack from remote side.

Signed-off-by: Deepak Kumar Singh <deesin@codeaurora.org>
Signed-off-by: Arun Kumar Neelakantam <aneela@codeaurora.org>
[bjorn: s/strlcpy/strscpy/]
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/1596086296-28529-5-git-send-email-deesin@codeaurora.org

drivers/rpmsg/qcom_glink_native.c

@@ -1524,6 +1524,7 @@ static void qcom_glink_rx_close(struct qcom_glink *glink, unsigned int rcid)
 
 		rpmsg_unregister_device(glink->dev, &chinfo);
 	}
+	channel->rpdev = NULL;
 
 	qcom_glink_send_close_ack(glink, channel->rcid);
 
@@ -1537,6 +1538,7 @@ static void qcom_glink_rx_close(struct qcom_glink *glink, unsigned int rcid)
 
 static void qcom_glink_rx_close_ack(struct qcom_glink *glink, unsigned int lcid)
 {
+	struct rpmsg_channel_info chinfo;
 	struct glink_channel *channel;
 	unsigned long flags;
 
@@ -1551,6 +1553,16 @@ static void qcom_glink_rx_close_ack(struct qcom_glink *glink, unsigned int lcid)
 	channel->lcid = 0;
 	spin_unlock_irqrestore(&glink->idr_lock, flags);
 
+	/* Decouple the potential rpdev from the channel */
+	if (channel->rpdev) {
+		strscpy(chinfo.name, channel->name, sizeof(chinfo.name));
+		chinfo.src = RPMSG_ADDR_ANY;
+		chinfo.dst = RPMSG_ADDR_ANY;
+
+		rpmsg_unregister_device(glink->dev, &chinfo);
+	}
+	channel->rpdev = NULL;
+
 	kref_put(&channel->refcount, qcom_glink_channel_release);
 }