Re: [PATCH 10/23] interconnect: qcom: rpmh: fix registration race

Konrad Dybcio
2023-02-03T02:55:27Z

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: 976daac4a1c5 ("interconnect: qcom: Consolidate interconnect RPMh support")
> Cc: stable@vger.kernel.org # 5.7
> Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
> ---
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>

Konrad
> drivers/interconnect/qcom/icc-rpmh.c | 25 +++++++++++++++----------
> 1 file changed, 15 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/interconnect/qcom/icc-rpmh.c b/drivers/interconnect/qcom/icc-rpmh.c
> index 5168bbf3d92f..fdb5e58e408b 100644
> --- 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_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;
> }