interconnect: qcom: rpm: 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: 62feb14ee8a3 ("interconnect: qcom: Consolidate interconnect RPM support")
Fixes: 30c8fa3ec61a ("interconnect: qcom: Add MSM8916 interconnect provider driver")
Cc: stable@vger.kernel.org	# 5.7
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Reviewed-by: Jun Nie <jun.nie@linaro.org>
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Link: https://lore.kernel.org/r/20230306075651.2449-9-johan+linaro@kernel.org
Signed-off-by: Georgi Djakov <djakov@kernel.org>

diff --git a/drivers/interconnect/qcom/icc-rpm.c b/drivers/interconnect/qcom/icc-rpm.c
index 91778cf..4180a06 100644 (file)
--- a/drivers/interconnect/qcom/icc-rpm.c
+++ b/drivers/interconnect/qcom/icc-rpm.c
@@ -503,7 +503,6 @@ regmap_done:
        }
 
        provider = &qp->provider;
-       INIT_LIST_HEAD(&provider->nodes);
        provider->dev = dev;
        provider->set = qcom_icc_set;
        provider->pre_aggregate = qcom_icc_pre_bw_aggregate;
@@ -511,12 +510,7 @@ regmap_done:
        provider->xlate_extended = qcom_icc_xlate_extended;
        provider->data = data;
 
-       ret = icc_provider_add(provider);
-       if (ret) {
-               dev_err(dev, "error adding interconnect provider: %d\n", ret);
-               clk_bulk_disable_unprepare(qp->num_clks, qp->bus_clks);
-               return ret;
-       }
+       icc_provider_init(provider);
 
        for (i = 0; i < num_nodes; i++) {
                size_t j;
@@ -524,7 +518,7 @@ regmap_done:
                node = icc_node_create(qnodes[i]->id);
                if (IS_ERR(node)) {
                        ret = PTR_ERR(node);
-                       goto err;
+                       goto err_remove_nodes;
                }
 
                node->name = qnodes[i]->name;
@@ -538,20 +532,26 @@ regmap_done:
        }
        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);
        clk_bulk_disable_unprepare(qp->num_clks, qp->bus_clks);
-       icc_provider_del(provider);
 
        return ret;
 }
@@ -561,9 +561,9 @@ int qnoc_remove(struct platform_device *pdev)
 {
        struct qcom_icc_provider *qp = platform_get_drvdata(pdev);
 
+       icc_provider_deregister(&qp->provider);
        icc_nodes_remove(&qp->provider);
        clk_bulk_disable_unprepare(qp->num_clks, qp->bus_clks);
-       icc_provider_del(&qp->provider);
 
        return 0;
 }