rpmsg: glink: Cancel pending intent requests at removal

During removal of the glink edge interrupts are disabled and no more
incoming messages are being serviced. In addition to the remote endpoint
being defunct that means that any outstanding requests for intents will
not be serviced, and qcom_glink_request_intent() will blindly wait for
up to 10 seconds.

Mark the intent request as not granted and complete the intent request
completion to fail the waiting client immediately.

Once the current intent request is failed, any potential clients waiting
for the intent request mutex will not enter the same wait, as the
qcom_glink_tx() call will fail fast.

Reviewed-by: Chris Lew <quic_clew@quicinc.com>
Signed-off-by: Bjorn Andersson <quic_bjorande@quicinc.com>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230213155215.1237059-7-quic_bjorande@quicinc.com

drivers/rpmsg/qcom_glink_native.c

@@ -423,6 +423,12 @@ static void qcom_glink_handle_intent_req_ack(struct qcom_glink *glink,
 	complete(&channel->intent_req_comp);
 }
 
+static void qcom_glink_intent_req_abort(struct glink_channel *channel)
+{
+	channel->intent_req_result = 0;
+	complete(&channel->intent_req_comp);
+}
+
 /**
  * qcom_glink_send_open_req() - send a RPM_CMD_OPEN request to the remote
  * @glink: Ptr to the glink edge
@@ -1788,6 +1794,12 @@ void qcom_glink_native_remove(struct qcom_glink *glink)
 	wake_up_all(&glink->tx_avail_notify);
 	spin_unlock_irqrestore(&glink->tx_lock, flags);
 
+	/* Abort any senders waiting for intent requests */
+	spin_lock_irqsave(&glink->idr_lock, flags);
+	idr_for_each_entry(&glink->lcids, channel, cid)
+		qcom_glink_intent_req_abort(channel);
+	spin_unlock_irqrestore(&glink->idr_lock, flags);
+
 	ret = device_for_each_child(glink->dev, NULL, qcom_glink_remove_device);
 	if (ret)
 		dev_warn(glink->dev, "Can't remove GLINK devices: %d\n", ret);