interconnect: qcom: rpmh: fix registration race

The current interconnect provider registration interface is inherently
racy as nodes are not added until the after adding the provider. This
can specifically cause racing DT lookups to fail.

Switch to using the new API where the provider is not registered until
after it has been fully initialised.

Fixes: 976daac ("interconnect: qcom: Consolidate interconnect RPMh support")
Cc: [email protected]      # 5.7
Reviewed-by: Konrad Dybcio <[email protected]>
Signed-off-by: Johan Hovold <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Georgi Djakov <[email protected]>

Author: jhovold

drivers/interconnect/qcom/icc-rpmh.c

@@ -192,9 +192,10 @@ int qcom_icc_rpmh_probe(struct platform_device *pdev)
 	provider->pre_aggregate = qcom_icc_pre_aggregate;
 	provider->aggregate = qcom_icc_aggregate;
 	provider->xlate_extended = qcom_icc_xlate_extended;
-	INIT_LIST_HEAD(&provider->nodes);
 	provider->data = data;
 
+	icc_provider_init(provider);
+
 	qp->dev = dev;
 	qp->bcms = desc->bcms;
 	qp->num_bcms = desc->num_bcms;
@@ -203,10 +204,6 @@ int qcom_icc_rpmh_probe(struct platform_device *pdev)
 	if (IS_ERR(qp->voter))
 		return PTR_ERR(qp->voter);
 
-	ret = icc_provider_add(provider);
-	if (ret)
-		return ret;
-
 	for (i = 0; i < qp->num_bcms; i++)
 		qcom_icc_bcm_init(qp->bcms[i], dev);
 
@@ -218,7 +215,7 @@ int qcom_icc_rpmh_probe(struct platform_device *pdev)
 		node = icc_node_create(qn->id);
 		if (IS_ERR(node)) {
 			ret = PTR_ERR(node);
-			goto err;
+			goto err_remove_nodes;
 		}
 
 		node->name = qn->name;
@@ -232,19 +229,27 @@ int qcom_icc_rpmh_probe(struct platform_device *pdev)
 	}
 
 	data->num_nodes = num_nodes;
+
+	ret = icc_provider_register(provider);
+	if (ret)
+		goto err_remove_nodes;
+
 	platform_set_drvdata(pdev, qp);
 
 	/* Populate child NoC devices if any */
 	if (of_get_child_count(dev->of_node) > 0) {
 		ret = of_platform_populate(dev->of_node, NULL, NULL, dev);
 		if (ret)
-			goto err;
+			goto err_deregister_provider;
 	}
 
 	return 0;
-err:
+
+err_deregister_provider:
+	icc_provider_deregister(provider);
+err_remove_nodes:
 	icc_nodes_remove(provider);
-	icc_provider_del(provider);
+
 	return ret;
 }
 EXPORT_SYMBOL_GPL(qcom_icc_rpmh_probe);
@@ -253,8 +258,8 @@ int qcom_icc_rpmh_remove(struct platform_device *pdev)
 {
 	struct qcom_icc_provider *qp = platform_get_drvdata(pdev);
 
+	icc_provider_deregister(&qp->provider);
 	icc_nodes_remove(&qp->provider);
-	icc_provider_del(&qp->provider);
 
 	return 0;
 }