netdev - Re: [PATCH v3 1/2] PM: runtime: Add pm_runtime_resume_and

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAJZ5v0hmhT4tg5hAD3jx7Xh=Ot7-jNMO0WtSS6-nz0Nw857+0w@mail.gmail.com>
Date:   Mon, 16 Nov 2020 13:49:10 +0100
From:   "Rafael J. Wysocki" <rafael@...nel.org>
To:     Zhang Qilong <zhangqilong3@...wei.com>
Cc:     "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Fugang Duan <fugang.duan@....com>,
        David Miller <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Linux PM <linux-pm@...r.kernel.org>,
        netdev <netdev@...r.kernel.org>
Subject: Re: [PATCH v3 1/2] PM: runtime: Add pm_runtime_resume_and_get to deal
 with usage counter

On Tue, Nov 10, 2020 at 10:25 AM Zhang Qilong <zhangqilong3@...wei.com> wrote:
>
> In many case, we need to check return value of pm_runtime_get_sync, but
> it brings a trouble to the usage counter processing. Many callers forget
> to decrease the usage counter when it failed, which could resulted in
> reference leak. It has been discussed a lot[0][1]. So we add a function
> to deal with the usage counter for better coding.
>
> [0]https://lkml.org/lkml/2020/6/14/88
> [1]https://patchwork.ozlabs.org/project/linux-tegra/list/?series=178139
> Signed-off-by: Zhang Qilong <zhangqilong3@...wei.com>

Acked-by: Rafael J. Wysocki  <rafael.j.wysocki@...el.com>

> ---
>  include/linux/pm_runtime.h | 21 +++++++++++++++++++++
>  1 file changed, 21 insertions(+)
>
> diff --git a/include/linux/pm_runtime.h b/include/linux/pm_runtime.h
> index 4b708f4e8eed..b492ae00cc90 100644
> --- a/include/linux/pm_runtime.h
> +++ b/include/linux/pm_runtime.h
> @@ -386,6 +386,27 @@ static inline int pm_runtime_get_sync(struct device *dev)
>         return __pm_runtime_resume(dev, RPM_GET_PUT);
>  }
>
> +/**
> + * pm_runtime_resume_and_get - Bump up usage counter of a device and resume it.
> + * @dev: Target device.
> + *
> + * Resume @dev synchronously and if that is successful, increment its runtime
> + * PM usage counter. Return 0 if the runtime PM usage counter of @dev has been
> + * incremented or a negative error code otherwise.
> + */
> +static inline int pm_runtime_resume_and_get(struct device *dev)
> +{
> +       int ret;
> +
> +       ret = __pm_runtime_resume(dev, RPM_GET_PUT);
> +       if (ret < 0) {
> +               pm_runtime_put_noidle(dev);
> +               return ret;
> +       }
> +
> +       return 0;
> +}
> +
>  /**
>   * pm_runtime_put - Drop device usage counter and queue up "idle check" if 0.
>   * @dev: Target device.
> --
> 2.25.4
>