[PATCH 11/23] interconnect: qcom: msm8974: fix registration race

[Johan Hovold]

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: 4e60a9568dc6 ("interconnect: qcom: add msm8974 driver")
Cc: stable at vger.kernel.org      # 5.5
Cc: Brian Masney <bmasney at redhat.com>
Signed-off-by: Johan Hovold <johan+linaro at kernel.org>
---
 drivers/interconnect/qcom/msm8974.c | 20 ++++++++------------
 1 file changed, 8 insertions(+), 12 deletions(-)

diff --git a/drivers/interconnect/qcom/msm8974.c b/drivers/interconnect/qcom/msm8974.c
index 5ea192f1141d..1828deaca443 100644
--- a/drivers/interconnect/qcom/msm8974.c
+++ b/drivers/interconnect/qcom/msm8974.c
@@ -692,7 +692,6 @@ static int msm8974_icc_probe(struct platform_device *pdev)
 		return ret;
 
 	provider = &qp->provider;
-	INIT_LIST_HEAD(&provider->nodes);
 	provider->dev = dev;
 	provider->set = msm8974_icc_set;
 	provider->aggregate = icc_std_aggregate;
@@ -700,11 +699,7 @@ static int msm8974_icc_probe(struct platform_device *pdev)
 	provider->data = data;
 	provider->get_bw = msm8974_get_bw;
 
-	ret = icc_provider_add(provider);
-	if (ret) {
-		dev_err(dev, "error adding interconnect provider: %d\n", ret);
-		goto err_disable_clks;
-	}
+	icc_provider_init(provider);
 
 	for (i = 0; i < num_nodes; i++) {
 		size_t j;
@@ -712,7 +707,7 @@ static int msm8974_icc_probe(struct platform_device *pdev)
 		node = icc_node_create(qnodes[i]->id);
 		if (IS_ERR(node)) {
 			ret = PTR_ERR(node);
-			goto err_del_icc;
+			goto err_remove_nodes;
 		}
 
 		node->name = qnodes[i]->name;
@@ -729,15 +724,16 @@ static int msm8974_icc_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);
 
 	return 0;
 
-err_del_icc:
+err_remove_nodes:
 	icc_nodes_remove(provider);
-	icc_provider_del(provider);
-
-err_disable_clks:
 	clk_bulk_disable_unprepare(qp->num_clks, qp->bus_clks);
 
 	return ret;
@@ -747,9 +743,9 @@ static int msm8974_icc_remove(struct platform_device *pdev)
 {
 	struct msm8974_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;
 }
-- 
2.39.1