linux-kernel - Re: [PATCH 10/12] PCI: dwc-plat: Simplify the probe method return value handling

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Message-ID: <20220324122336.GJ2854@thinkpad>
Date:   Thu, 24 Mar 2022 17:53:36 +0530
From:   Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
To:     Serge Semin <Sergey.Semin@...kalelectronics.ru>
Cc:     Jingoo Han <jingoohan1@...il.com>,
        Gustavo Pimentel <gustavo.pimentel@...opsys.com>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Rob Herring <robh@...nel.org>,
        Krzysztof Wilczyński <kw@...ux.com>,
        Serge Semin <fancer.lancer@...il.com>,
        Alexey Malahov <Alexey.Malahov@...kalelectronics.ru>,
        Pavel Parkhomenko <Pavel.Parkhomenko@...kalelectronics.ru>,
        Frank Li <Frank.Li@....com>, linux-pci@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 10/12] PCI: dwc-plat: Simplify the probe method return
 value handling

On Thu, Mar 24, 2022 at 04:25:21AM +0300, Serge Semin wrote:
> The whole switch-case-logic implemented in the DWC PCIe RC/EP probe
> procedure doesn't seem well thought through. First of all the ret variable
> is unused in the EP-case and is only partly involved in the RC-case of the
> switch-case statement, which unnecessary complicates the code. Secondly
> the probe method will return zero if an unknown mode is detected. That is
> improbable situation since the OF-device data is initialized only with
> valid modes, but such code is still wrong at least from maintainability
> point of view. So let's convert the switch-case part of the probe function
> to being more coherent. We suggest to use the local ret variable to
> preserve the status of the case-clauses and return its value from the
> probe procedure after the work is done.
> 
> Signed-off-by: Serge Semin <Sergey.Semin@...kalelectronics.ru>

Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>

Thanks,
Mani

> ---
>  drivers/pci/controller/dwc/pcie-designware-plat.c | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-designware-plat.c b/drivers/pci/controller/dwc/pcie-designware-plat.c
> index 0c5de87d3cc6..fea785096261 100644
> --- a/drivers/pci/controller/dwc/pcie-designware-plat.c
> +++ b/drivers/pci/controller/dwc/pcie-designware-plat.c
> @@ -153,20 +153,21 @@ static int dw_plat_pcie_probe(struct platform_device *pdev)
>  			return -ENODEV;
>  
>  		ret = dw_plat_add_pcie_port(dw_plat_pcie, pdev);
> -		if (ret < 0)
> -			return ret;
>  		break;
>  	case DW_PCIE_EP_TYPE:
>  		if (!IS_ENABLED(CONFIG_PCIE_DW_PLAT_EP))
>  			return -ENODEV;
>  
>  		pci->ep.ops = &pcie_ep_ops;
> -		return dw_pcie_ep_init(&pci->ep);
> +		ret = dw_pcie_ep_init(&pci->ep);
> +		break;
>  	default:
>  		dev_err(dev, "INVALID device type %d\n", dw_plat_pcie->mode);
> +		ret = -EINVAL;
> +		break;
>  	}
>  
> -	return 0;
> +	return ret;
>  }
>  
>  static const struct dw_plat_pcie_of_data dw_plat_pcie_rc_of_data = {
> -- 
> 2.35.1
>