linux-kernel - Re: [PATCH 2/3] PCI: Use PM runtime class macro for the auto cleanup

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Message-ID: <CAJZ5v0jbr8WKp3+POEMy_mz2daWMGDPWHGMhWc-Ac=rcPAzDkg@mail.gmail.com>
Date: Fri, 19 Sep 2025 20:39:04 +0200
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: Takashi Iwai <tiwai@...e.de>
Cc: "Rafael J . Wysocki" <rafael@...nel.org>, linux-pm@...r.kernel.org, 
	Bjorn Helgaas <bhelgaas@...gle.com>, linux-pci@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/3] PCI: Use PM runtime class macro for the auto cleanup

On Fri, Sep 19, 2025 at 6:32 PM Takashi Iwai <tiwai@...e.de> wrote:
>
> Use the newly introduced class macro to simplify the code.
> Also, add the proper error handling for the PM runtime get errors,
> too.
>
> Signed-off-by: Takashi Iwai <tiwai@...e.de>
> ---
>  drivers/pci/pci-sysfs.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
> index 5eea14c1f7f5..08e5cf2ba73e 100644
> --- a/drivers/pci/pci-sysfs.c
> +++ b/drivers/pci/pci-sysfs.c
> @@ -1475,8 +1475,9 @@ static ssize_t reset_method_store(struct device *dev,
>                 return count;
>         }
>
> -       pm_runtime_get_sync(dev);
> -       struct device *pmdev __free(pm_runtime_put) = dev;
> +       CLASS(pm_runtime_resume_and_get, pmdev)(dev);
> +       if (IS_ERR(pmdev))
> +               return -ENXIO;
>
>         if (sysfs_streq(buf, "default")) {
>                 pci_init_reset_methods(pdev);
> --

I've just realized that this patch won't work and the reason why is
that __pm_runtime_resume() returns an error if runtime PM is disabled
for a device, so pmdev above will be an error pointer in that case.

One possible approach may be to make pm_runtime_resume_and_get_dev()
return 0 and bump up the usage counter for devices with runtime PM
disabled.