soc: qcom: Notify to app pd clients in ind_ack thread

We have observed race condition between inquiring the remote pd state and
indication call back execution. They run asynchronously so we have no
control on their concurrent execution. So to achieve mutual exclusion,
moving the portion of code which result in race condition to indication
acknowledgment routine. Indication acknowledgment is send in separate
thread context which will avoid race condition.

Change-Id: Ib94f7ef4efd5de63fc8bededcf5cb6ae4ca2c3d8
Signed-off-by: Avaneesh Kumar Dwivedi <akdwived@codeaurora.org>

drivers/soc/qcom/service-notifier.c

@@ -84,6 +84,7 @@ static DEFINE_MUTEX(service_list_lock);
 struct ind_req_resp {
 	char service_path[SERVREG_NOTIF_NAME_LENGTH];
 	int transaction_id;
+	int curr_state;
 };
 
 /*
@@ -200,8 +201,30 @@ static void send_ind_ack(struct work_struct *work)
 	struct qmi_servreg_notif_set_ack_req_msg_v01 req;
 	struct msg_desc req_desc, resp_desc;
 	struct qmi_servreg_notif_set_ack_resp_msg_v01 resp = { { 0, 0 } };
+	struct service_notif_info *service_notif;
+	enum pd_subsys_state state = USER_PD_STATE_CHANGE;
 	int rc;
 
+	service_notif = _find_service_info(data->ind_msg.service_path);
+	if (!service_notif)
+		return;
+	if ((int)data->ind_msg.curr_state < QMI_STATE_MIN_VAL ||
+		(int)data->ind_msg.curr_state > QMI_STATE_MAX_VAL)
+		pr_err("Unexpected indication notification state %d\n",
+			data->ind_msg.curr_state);
+	else {
+		mutex_lock(&notif_add_lock);
+		mutex_lock(&service_list_lock);
+		rc = service_notif_queue_notification(service_notif,
+			data->ind_msg.curr_state, &state);
+		if (rc & NOTIFY_STOP_MASK)
+			pr_err("Notifier callback aborted for %s with error %d\n",
+				data->ind_msg.service_path, rc);
+		service_notif->curr_state = data->ind_msg.curr_state;
+		mutex_unlock(&service_list_lock);
+		mutex_unlock(&notif_add_lock);
+	}
+
 	req.transaction_id = data->ind_msg.transaction_id;
 	snprintf(req.service_name, ARRAY_SIZE(req.service_name), "%s",
 						data->ind_msg.service_path);
@@ -236,11 +259,9 @@ static void root_service_service_ind_cb(struct qmi_handle *handle,
 				unsigned int msg_len, void *ind_cb_priv)
 {
 	struct qmi_client_info *data = (struct qmi_client_info *)ind_cb_priv;
-	struct service_notif_info *service_notif;
 	struct msg_desc ind_desc;
 	struct qmi_servreg_notif_state_updated_ind_msg_v01 ind_msg = {
 					QMI_STATE_MIN_VAL, "", 0xFFFF };
-	enum pd_subsys_state state = USER_PD_STATE_CHANGE;
 	int rc;
 
 	ind_desc.msg_id = SERVREG_NOTIF_STATE_UPDATED_IND_MSG;
@@ -256,27 +277,8 @@ static void root_service_service_ind_cb(struct qmi_handle *handle,
 		ind_msg.service_name, ind_msg.curr_state,
 		ind_msg.transaction_id);
 
-	service_notif = _find_service_info(ind_msg.service_name);
-	if (!service_notif)
-		return;
-
-	if ((int)ind_msg.curr_state < QMI_STATE_MIN_VAL ||
-			(int)ind_msg.curr_state > QMI_STATE_MAX_VAL)
-		pr_err("Unexpected indication notification state %d\n",
-							ind_msg.curr_state);
-	else {
-		mutex_lock(&notif_add_lock);
-		mutex_lock(&service_list_lock);
-		rc = service_notif_queue_notification(service_notif,
-					ind_msg.curr_state, &state);
-		if (rc & NOTIFY_STOP_MASK)
-			pr_err("Notifier callback aborted for %s with error %d\n",
-						ind_msg.service_name, rc);
-		service_notif->curr_state = ind_msg.curr_state;
-		mutex_unlock(&service_list_lock);
-		mutex_unlock(&notif_add_lock);
-	}
 	data->ind_msg.transaction_id = ind_msg.transaction_id;
+	data->ind_msg.curr_state = ind_msg.curr_state;
 	snprintf(data->ind_msg.service_path,
 		ARRAY_SIZE(data->ind_msg.service_path), "%s",
 		ind_msg.service_name);
@@ -373,6 +375,12 @@ static void root_service_service_arrive(struct work_struct *work)
 	mutex_unlock(&qmi_client_release_lock);
 	pr_info("Connection established between QMI handle and %d service\n",
 							data->instance_id);
+	/* Register for indication messages about service */
+	rc = qmi_register_ind_cb(data->clnt_handle,
+		root_service_service_ind_cb, (void *)data);
+	if (rc < 0)
+		pr_err("Indication callback register failed(instance-id: %d) rc:%d\n",
+			data->instance_id, rc);
 	mutex_lock(&notif_add_lock);
 	mutex_lock(&service_list_lock);
 	list_for_each_entry(service_notif, &service_list, list) {
@@ -395,12 +403,6 @@ static void root_service_service_arrive(struct work_struct *work)
 	}
 	mutex_unlock(&service_list_lock);
 	mutex_unlock(&notif_add_lock);
-	/* Register for indication messages about service */
-	rc = qmi_register_ind_cb(data->clnt_handle,
-		root_service_service_ind_cb, (void *)data);
-	if (rc < 0)
-		pr_err("Indication callback register failed(instance-id: %d) rc:%d\n",
-							data->instance_id, rc);
 }
 
 static void root_service_service_exit(struct qmi_client_info *data,