Re: [PATCH 08/23] interconnect: qcom: rpm: fix registration race

Konrad Dybcio
2023-02-03T02:54:10Z

On 1.02.2023 11:15, Johan Hovold wrote:
> 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
> Cc: Jun Nie <jun.nie@linaro.org>
> Cc: Georgi Djakov <georgi.djakov@linaro.org>
> Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
> ---
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>

Konrad
> drivers/interconnect/qcom/icc-rpm.c | 23 ++++++++++++-----------
> 1 file changed, 12 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/interconnect/qcom/icc-rpm.c b/drivers/interconnect/qcom/icc-rpm.c
> index da595059cafd..4d0997b210f7 100644
> --- a/drivers/interconnect/qcom/icc-rpm.c
> +++ b/drivers/interconnect/qcom/icc-rpm.c
> @@ -502,7 +502,6 @@ int qnoc_probe(struct platform_device *pdev)
> }
>
> provider = &qp->provider;
> - INIT_LIST_HEAD(&provider->nodes);
> provider->dev = dev;
> provider->set = qcom_icc_set;
> provider->pre_aggregate = qcom_icc_pre_bw_aggregate;
> @@ -510,11 +509,7 @@ int qnoc_probe(struct platform_device *pdev)
> 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);
> - goto err_disable_clks;
> - }
> + icc_provider_init(provider);
>
> for (i = 0; i < num_nodes; i++) {
> size_t j;
> @@ -522,7 +517,7 @@ int qnoc_probe(struct platform_device *pdev)
> 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;
> @@ -536,19 +531,25 @@ int qnoc_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);
> err_disable_clks:
> clk_bulk_disable_unprepare(qp->num_clks, qp->bus_clks);
>
> @@ -560,9 +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;
> }