linux-kernel - Re: [PATCH 2/3] gpio: pxa: Fix return value of pxa_gpio

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Message-ID: <CAMpxmJXc5-+hj5p2GTMJR4MZX95YWpTTg5FHD79au8pdcYi6mA@mail.gmail.com>
Date:   Mon, 25 May 2020 11:14:23 +0200
From:   Bartosz Golaszewski <bgolaszewski@...libre.com>
To:     Tiezhu Yang <yangtiezhu@...ngson.cn>
Cc:     Robert Jarzmik <robert.jarzmik@...e.fr>,
        Linus Walleij <linus.walleij@...aro.org>,
        Ray Jui <rjui@...adcom.com>,
        bcm-kernel-feedback-list@...adcom.com,
        linux-gpio <linux-gpio@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Xuefeng Li <lixuefeng@...ngson.cn>
Subject: Re: [PATCH 2/3] gpio: pxa: Fix return value of pxa_gpio_probe()

sob., 23 maj 2020 o 05:25 Tiezhu Yang <yangtiezhu@...ngson.cn> napisał(a):
>
> On 05/23/2020 03:07 AM, Robert Jarzmik wrote:
> > Tiezhu Yang <yangtiezhu@...ngson.cn> writes:
> >
> >> When call function devm_platform_ioremap_resource(), we should use IS_ERR()
> >> to check the return value and return PTR_ERR() if failed.
> >>
> >> Fixes: 542c25b7a209 ("drivers: gpio: pxa: use devm_platform_ioremap_resource()")
> >> Signed-off-by: Tiezhu Yang <yangtiezhu@...ngson.cn>
> >> ---
> >>   drivers/gpio/gpio-pxa.c | 4 ++--
> >>   1 file changed, 2 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/drivers/gpio/gpio-pxa.c b/drivers/gpio/gpio-pxa.c
> >> index 1361270..0cb6600 100644
> >> --- a/drivers/gpio/gpio-pxa.c
> >> +++ b/drivers/gpio/gpio-pxa.c
> >> @@ -660,8 +660,8 @@ static int pxa_gpio_probe(struct platform_device *pdev)
> >>      pchip->irq1 = irq1;
> >>
> >>      gpio_reg_base = devm_platform_ioremap_resource(pdev, 0);
> >> -    if (!gpio_reg_base)
> >> -            return -EINVAL;
> >> +    if (IS_ERR(gpio_reg_base))
> >> +            return PTR_ERR(gpio_reg_base);
> > As far as I know, devm_platform_ioremap_resource() could return NULL which is
> > not handled by this test (unless __devm_ioremap() semantics changed since I had
> > a look).
>
> Hi Robert,
>
> In the function __devm_ioremap_resource(), if __devm_ioremap returns NULL,
> it will return IOMEM_ERR_PTR(-ENOMEM).
>
> devm_platform_ioremap_resource()
>          devm_ioremap_resource()
>                  __devm_ioremap_resource()
>                         __devm_ioremap()
>
> static void __iomem *
> __devm_ioremap_resource(struct device *dev, const struct resource *res,
>              enum devm_ioremap_type type)
> {
> ...
>      dest_ptr = __devm_ioremap(dev, res->start, size, type);
>      if (!dest_ptr) {
>          dev_err(dev, "ioremap failed for resource %pR\n", res);
>          devm_release_mem_region(dev, res->start, size);
>          dest_ptr = IOMEM_ERR_PTR(-ENOMEM);
>      }
>
>      return dest_ptr;
> }
>
> And also, we can see the comment of devm_ioremap_resource():
>
> Usage example:
>
>          res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>          base = devm_ioremap_resource(&pdev->dev, res);
>          if (IS_ERR(base))
>                  return PTR_ERR(base);
>
> >
> > Therefore, this patch is incorrect, or rather incomplete.
>
> So I think this patch is correct, do I miss something?
>
>

Yes, this patch is correct. Applied for fixes.

Bart