linux-kernel - Re: [PATCH] PCI: qcom: Fix error handling in pm

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Message-ID: <20180629095602.GB9576@red-moon>
Date:   Fri, 29 Jun 2018 10:56:02 +0100
From:   Lorenzo Pieralisi <lorenzo.pieralisi@....com>
To:     Bjorn Andersson <bjorn.andersson@...aro.org>
Cc:     Stanimir Varbanov <svarbanov@...sol.com>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Srinivas Kandagatla <srinivas.kandagatla@...aro.org>,
        linux-pci@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] PCI: qcom: Fix error handling in pm_runtime support

On Fri, May 25, 2018 at 12:09:34PM -0700, Bjorn Andersson wrote:
> The driver does not cope with the fact that probe can fail in a number
> of cases after enabling pm_runtime on the device, this results in
> warnings about "Unbalanced pm_runtime_enable". Further more if probe
> fails after invoking host_init the power-domain will be left referenced.
> 
> As it's not possible for the error handling in qcom_pcie_host_init() to
> handle errors happening after returning from that function the
> pm_runtime_get_sync() is moved to probe() as well.
> 
> Signed-off-by: Bjorn Andersson <bjorn.andersson@...aro.org>
> ---
> 
> I'm sorry for not spotting this last week when we discussed the previous patch.

I need Stanimir's ACK to merge it, thanks.

Lorenzo

>  drivers/pci/dwc/pcie-qcom.c | 65 ++++++++++++++++++++++++++-----------
>  1 file changed, 46 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/pci/dwc/pcie-qcom.c b/drivers/pci/dwc/pcie-qcom.c
> index 3f35098b71b1..f2453196278f 100644
> --- a/drivers/pci/dwc/pcie-qcom.c
> +++ b/drivers/pci/dwc/pcie-qcom.c
> @@ -1088,8 +1088,6 @@ static int qcom_pcie_host_init(struct pcie_port *pp)
>  	struct qcom_pcie *pcie = to_qcom_pcie(pci);
>  	int ret;
>  
> -	pm_runtime_get_sync(pci->dev);
> -
>  	qcom_ep_reset_assert(pcie);
>  
>  	ret = pcie->ops->init(pcie);
> @@ -1126,7 +1124,6 @@ static int qcom_pcie_host_init(struct pcie_port *pp)
>  	phy_power_off(pcie->phy);
>  err_deinit:
>  	pcie->ops->deinit(pcie);
> -	pm_runtime_put_sync(pci->dev);
>  
>  	return ret;
>  }
> @@ -1207,7 +1204,6 @@ static int qcom_pcie_probe(struct platform_device *pdev)
>  	struct qcom_pcie *pcie;
>  	int ret;
>  
> -
>  	pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL);
>  	if (!pcie)
>  		return -ENOMEM;
> @@ -1217,6 +1213,7 @@ static int qcom_pcie_probe(struct platform_device *pdev)
>  		return -ENOMEM;
>  
>  	pm_runtime_enable(dev);
> +	pm_runtime_get_sync(dev);
>  
>  	pci->dev = dev;
>  	pci->ops = &dw_pcie_ops;
> @@ -1227,53 +1224,82 @@ static int qcom_pcie_probe(struct platform_device *pdev)
>  	pcie->ops = of_device_get_match_data(dev);
>  
>  	pcie->reset = devm_gpiod_get_optional(dev, "perst", GPIOD_OUT_LOW);
> -	if (IS_ERR(pcie->reset))
> -		return PTR_ERR(pcie->reset);
> +	if (IS_ERR(pcie->reset)) {
> +		ret = PTR_ERR(pcie->reset);
> +		goto err_pm_runtime_put;
> +	}
>  
>  	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "parf");
>  	pcie->parf = devm_ioremap_resource(dev, res);
> -	if (IS_ERR(pcie->parf))
> -		return PTR_ERR(pcie->parf);
> +	if (IS_ERR(pcie->parf)) {
> +		ret = PTR_ERR(pcie->parf);
> +		goto err_pm_runtime_put;
> +	}
>  
>  	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dbi");
>  	pci->dbi_base = devm_pci_remap_cfg_resource(dev, res);
> -	if (IS_ERR(pci->dbi_base))
> -		return PTR_ERR(pci->dbi_base);
> +	if (IS_ERR(pci->dbi_base)) {
> +		ret = PTR_ERR(pci->dbi_base);
> +		goto err_pm_runtime_put;
> +	}
>  
>  	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "elbi");
>  	pcie->elbi = devm_ioremap_resource(dev, res);
> -	if (IS_ERR(pcie->elbi))
> -		return PTR_ERR(pcie->elbi);
> +	if (IS_ERR(pcie->elbi)) {
> +		ret = PTR_ERR(pcie->elbi);
> +		goto err_pm_runtime_put;
> +	}
>  
>  	pcie->phy = devm_phy_optional_get(dev, "pciephy");
> -	if (IS_ERR(pcie->phy))
> -		return PTR_ERR(pcie->phy);
> +	if (IS_ERR(pcie->phy)) {
> +		ret = PTR_ERR(pcie->phy);
> +		goto err_pm_runtime_put;
> +	}
>  
>  	ret = pcie->ops->get_resources(pcie);
>  	if (ret)
> -		return ret;
> +		goto err_pm_runtime_put;
>  
>  	pp->root_bus_nr = -1;
>  	pp->ops = &qcom_pcie_dw_ops;
>  
>  	if (IS_ENABLED(CONFIG_PCI_MSI)) {
>  		pp->msi_irq = platform_get_irq_byname(pdev, "msi");
> -		if (pp->msi_irq < 0)
> -			return pp->msi_irq;
> +		if (pp->msi_irq < 0) {
> +			ret = pp->msi_irq;
> +			goto err_pm_runtime_put;
> +		}
>  	}
>  
>  	ret = phy_init(pcie->phy);
>  	if (ret)
> -		return ret;
> +		goto err_pm_runtime_put;
>  
>  	platform_set_drvdata(pdev, pcie);
>  
>  	ret = dw_pcie_host_init(pp);
>  	if (ret) {
>  		dev_err(dev, "cannot initialize host\n");
> -		return ret;
> +		goto err_pm_runtime_put;
>  	}
>  
> +	return 0;
> +
> +err_pm_runtime_put:
> +	pm_runtime_put(dev);
> +	pm_runtime_disable(dev);
> +
> +	return ret;
> +}
> +
> +static int qcom_pcie_remove(struct platform_device *pdev)
> +{
> +	struct qcom_pcie *pcie = platform_get_drvdata(pdev);
> +	struct device *dev = pcie->pci->dev;
> +
> +	pm_runtime_put(dev);
> +	pm_runtime_disable(dev);
> +
>  	return 0;
>  }
>  
> @@ -1289,6 +1315,7 @@ static const struct of_device_id qcom_pcie_match[] = {
>  
>  static struct platform_driver qcom_pcie_driver = {
>  	.probe = qcom_pcie_probe,
> +	.remove = qcom_pcie_remove,
>  	.driver = {
>  		.name = "qcom-pcie",
>  		.suppress_bind_attrs = true,
> -- 
> 2.17.0
>