linux-kernel - Re: [PATCH v2 3/7] pmdomain: core: Use dev_name() instead of kobject_get

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Message-ID: <CAPDyKFqcpxUJWL7FoRSXLXVhS5B9PjcTY5ryG8HAY_E1Btgwag@mail.gmail.com>
Date: Tue, 20 Aug 2024 10:57:43 +0200
From: Ulf Hansson <ulf.hansson@...aro.org>
To: Geert Uytterhoeven <geert@...ux-m68k.org>
Cc: "Rafael J . Wysocki" <rafael@...nel.org>, Sudeep Holla <sudeep.holla@....com>, linux-pm@...r.kernel.org, 
	Lorenzo Pieralisi <Lorenzo.Pieralisi@....com>, Nikunj Kela <nkela@...cinc.com>, 
	Prasad Sodagudi <psodagud@...cinc.com>, Maulik Shah <quic_mkshah@...cinc.com>, 
	Daniel Lezcano <daniel.lezcano@...aro.org>, 
	Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>, linux-rt-users@...r.kernel.org, 
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 3/7] pmdomain: core: Use dev_name() instead of
 kobject_get_path() in debugfs

On Tue, 20 Aug 2024 at 10:55, Geert Uytterhoeven <geert@...ux-m68k.org> wrote:
>
> Hi Ulf,
>
> On Mon, May 27, 2024 at 4:27 PM Ulf Hansson <ulf.hansson@...aro.org> wrote:
> > Using kobject_get_path() means a dynamic memory allocation gets done, which
> > doesn't work on a PREEMPT_RT based configuration while holding genpd's raw
> > spinlock.
> >
> > To fix the problem, let's convert into using the simpler dev_name(). This
> > means the information about the path doesn't get presented in debugfs, but
> > hopefully this shouldn't be an issue.
> >
> > Signed-off-by: Ulf Hansson <ulf.hansson@...aro.org>
> > ---
> > Changes in v2:
> >         - New patch.
>
> Thanks for your patch, which is now commit 9094e53ff5c86ebe ("pmdomain:
> core: Use dev_name() instead of kobject_get_path() in debugfs")
> in pmdomain/next.
>
> > --- a/drivers/pmdomain/core.c
> > +++ b/drivers/pmdomain/core.c
> > @@ -3215,16 +3214,9 @@ static int genpd_summary_one(struct seq_file *s,
> >         }
> >
> >         list_for_each_entry(pm_data, &genpd->dev_list, list_node) {
> > -               kobj_path = kobject_get_path(&pm_data->dev->kobj,
> > -                               genpd_is_irq_safe(genpd) ?
> > -                               GFP_ATOMIC : GFP_KERNEL);
> > -               if (kobj_path == NULL)
> > -                       continue;
> > -
> > -               seq_printf(s, "\n    %-50s  ", kobj_path);
> > +               seq_printf(s, "\n    %-50s  ", dev_name(pm_data->dev));
>
> While some of the old names didn't even fit in 50 characters, the new
> names need much less space, so perhaps this is a good opportunity to
> decrease the table width?

Sure, it seems reasonable! Do you want to send a patch?

>
> >                 rtpm_status_str(s, pm_data->dev);
> >                 perf_status_str(s, pm_data->dev);
> > -               kfree(kobj_path);
> >         }
> >
> >         seq_puts(s, "\n");

Kind regards
Uffe