[PATCH 6.2 138/211] interconnect: qcom: rpmh: fix registration race

[Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>]

From: Johan Hovold <johan+linaro@xxxxxxxxxx>

commit 74240a5bebd48d8b843c6d0f1acfaa722a5abeb7 upstream.

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: 976daac4a1c5 ("interconnect: qcom: Consolidate interconnect RPMh support")
Cc: stable@xxxxxxxxxxxxxxx      # 5.7
Reviewed-by: Konrad Dybcio <konrad.dybcio@xxxxxxxxxx>
Signed-off-by: Johan Hovold <johan+linaro@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20230306075651.2449-11-johan+linaro@xxxxxxxxxx
Signed-off-by: Georgi Djakov <djakov@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/interconnect/qcom/icc-rpmh.c |   25 +++++++++++++++----------
 1 file changed, 15 insertions(+), 10 deletions(-)

--- a/drivers/interconnect/qcom/icc-rpmh.c
+++ b/drivers/interconnect/qcom/icc-rpmh.c
@@ -192,9 +192,10 @@ int qcom_icc_rpmh_probe(struct platform_
 	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_
 	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_
 		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_
 	}
 
 	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
 {
 	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;
 }