linux-kernel - Re: [PATCH v2 3/8] PM / Domains: Add lockdep asserts for domains list mutex

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Date:   Mon, 12 Jun 2017 21:09:59 +0200
From:   Ulf Hansson <ulf.hansson@...aro.org>
To:     Krzysztof Kozlowski <krzk@...nel.org>
Cc:     "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Kevin Hilman <khilman@...nel.org>,
        Len Brown <len.brown@...el.com>, Pavel Machek <pavel@....cz>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 3/8] PM / Domains: Add lockdep asserts for domains list mutex

On 12 June 2017 at 17:17, Krzysztof Kozlowski <krzk@...nel.org> wrote:
> Add lockdep checks for holding mutex protecting the list of domains.
> This might expose misuse even though only file-scope functions use it
> for now.

I think it seems a bit silly to use these lockdep checks as these
functions are as you state above, static functions. Moreover there are
called from a quite limited amount of places.

Do you really think this add some value?

Kind regards
Uffe

>
> Signed-off-by: Krzysztof Kozlowski <krzk@...nel.org>
> ---
>  drivers/base/power/domain.c | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
> index 983f086ab235..9d3d3c2a5979 100644
> --- a/drivers/base/power/domain.c
> +++ b/drivers/base/power/domain.c
> @@ -726,6 +726,8 @@ static bool pm_genpd_present(const struct generic_pm_domain *genpd)
>  {
>         const struct generic_pm_domain *gpd;
>
> +       lockdep_assert_held(&gpd_list_lock);
> +
>         if (IS_ERR_OR_NULL(genpd))
>                 return false;
>
> @@ -1321,6 +1323,8 @@ static int genpd_add_subdomain(struct generic_pm_domain *genpd,
>         struct gpd_link *link, *itr;
>         int ret = 0;
>
> +       lockdep_assert_held(&gpd_list_lock);
> +
>         if (IS_ERR_OR_NULL(genpd) || IS_ERR_OR_NULL(subdomain)
>             || genpd == subdomain)
>                 return -EINVAL;
> @@ -1528,6 +1532,8 @@ static int genpd_remove(struct generic_pm_domain *genpd)
>  {
>         struct gpd_link *l, *link;
>
> +       lockdep_assert_held(&gpd_list_lock);
> +
>         if (IS_ERR_OR_NULL(genpd))
>                 return -EINVAL;
>
> --
> 2.9.3
>