linux-kernel - Re: [PATCH] PCI: v3: fix missing clk_disable_unprepare() on error in v3_pci

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Date:   Mon, 2 Nov 2020 07:48:08 -0600
From:   Rob Herring <robh@...nel.org>
To:     Qinglang Miao <miaoqinglang@...wei.com>
Cc:     Linus Walleij <linus.walleij@...aro.org>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        PCI <linux-pci@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] PCI: v3: fix missing clk_disable_unprepare() on error in v3_pci_probe

On Thu, Oct 29, 2020 at 8:28 PM Qinglang Miao <miaoqinglang@...wei.com> wrote:
>
> Fix the missing clk_disable_unprepare() before return
> from v3_pci_probe() in the error handling case.
>
> Signed-off-by: Qinglang Miao <miaoqinglang@...wei.com>
> ---
>  drivers/pci/controller/pci-v3-semi.c | 14 +++++++++++---
>  1 file changed, 11 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/pci/controller/pci-v3-semi.c b/drivers/pci/controller/pci-v3-semi.c
> index 154a53986..e24abc5b4 100644
> --- a/drivers/pci/controller/pci-v3-semi.c
> +++ b/drivers/pci/controller/pci-v3-semi.c
> @@ -739,8 +739,10 @@ static int v3_pci_probe(struct platform_device *pdev)
>
>         regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>         v3->base = devm_ioremap_resource(dev, regs);
> -       if (IS_ERR(v3->base))
> +       if (IS_ERR(v3->base)) {
> +               clk_disable_unprepare(clk);

You can reorder things moving the clock enable later (after mapping
resources, but before devm_request_irq) and avoid some of these. Also
move this check down:

if (readl(v3->base + V3_LB_IO_BASE) != (regs->start >> 16))


>                 return PTR_ERR(v3->base);
> +       }
>         /*
>          * The hardware has a register with the physical base address
>          * of the V3 controller itself, verify that this is the same
> @@ -754,17 +756,22 @@ static int v3_pci_probe(struct platform_device *pdev)
>         regs = platform_get_resource(pdev, IORESOURCE_MEM, 1);
>         if (resource_size(regs) != SZ_16M) {
>                 dev_err(dev, "config mem is not 16MB!\n");
> +               clk_disable_unprepare(clk);
>                 return -EINVAL;
>         }
>         v3->config_mem = regs->start;
>         v3->config_base = devm_ioremap_resource(dev, regs);
> -       if (IS_ERR(v3->config_base))
> +       if (IS_ERR(v3->config_base)) {
> +               clk_disable_unprepare(clk);
>                 return PTR_ERR(v3->config_base);
> +       }
>
>         /* Get and request error IRQ resource */
>         irq = platform_get_irq(pdev, 0);
> -       if (irq < 0)
> +       if (irq < 0) {
> +               clk_disable_unprepare(clk);
>                 return irq;
> +       }
>
>         ret = devm_request_irq(dev, irq, v3_irq, 0,
>                         "PCIv3 error", v3);
> @@ -772,6 +779,7 @@ static int v3_pci_probe(struct platform_device *pdev)
>                 dev_err(dev,
>                         "unable to request PCIv3 error IRQ %d (%d)\n",
>                         irq, ret);
> +               clk_disable_unprepare(clk);
>                 return ret;

You still leave the clock enabled if pci_host_probe() fails.

Rob