linux-kernel - Re: [PATCH v7 12/14] cpufreq: Add Kryo CPU scaling driver

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Date:   Wed, 16 May 2018 17:13:44 +0300
From:   Amit Kucheria <amit.kucheria@...aro.org>
To:     Viresh Kumar <viresh.kumar@...aro.org>
Cc:     Ilia Lin <ilialin@...eaurora.org>,
        Michael Turquette <mturquette@...libre.com>, sboyd@...nel.org,
        Rob Herring <robh@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        "Menon, Nishanth" <nm@...com>, lgirdwood@...il.com,
        Mark Brown <broonie@...nel.org>,
        Andy Gross <andy.gross@...aro.org>,
        David Brown <david.brown@...aro.org>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will.deacon@....com>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>, linux-clk@...r.kernel.org,
        DTML <devicetree@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Linux PM list <linux-pm@...r.kernel.org>,
        linux-arm-msm <linux-arm-msm@...r.kernel.org>,
        "open list:ARM/QUALCOMM SUPPORT" <linux-soc@...r.kernel.org>,
        lakml <linux-arm-kernel@...ts.infradead.org>,
        Rajendra Nayak <rnayak@...eaurora.org>,
        Nicolas Dechesne <nicolas.dechesne@...aro.org>,
        celster@...eaurora.org, tfinkel@...eaurora.org
Subject: Re: [PATCH v7 12/14] cpufreq: Add Kryo CPU scaling driver

On Wed, May 16, 2018 at 5:11 PM, Viresh Kumar <viresh.kumar@...aro.org> wrote:
> On 16-05-18, 16:12, Amit Kucheria wrote:
>> > +       ret = PTR_ERR_OR_ZERO(opp_temp =
>> > +                             dev_pm_opp_set_supported_hw(cpu_dev,&versions,1));
>> > +       if (0 > ret)
>>
>> Any particular reason to prefer this over (ret < 0) that is generally
>> used? I've seen it used to avoid the == vs. = typos, but not for other
>> comparisons.
>>
>> Suggest sticking to what is commonly used i.e. ret < 0.
>>
>> > +               goto free_opp;
>> > +
>> > +       cpu_dev = get_cpu_device(GOLD_LEAD);
>>
>> Error check cpu_dev here?
>>
>> > +       ret = PTR_ERR_OR_ZERO(opp_temp =
>> > +                             dev_pm_opp_set_supported_hw(cpu_dev,&versions,1));
>> > +       if (0 > ret)
>> > +               goto free_opp;
>
> The goto here is wrong
>
>> > +
>> > +
>> > +       ret = PTR_ERR_OR_ZERO(platform_device_register_simple("cpufreq-dt",
>> > +                                                             -1, NULL, 0));
>> > +
>> > +       if (0 == ret)
>> > +               return 0;
>> > +
>> > +free_opp:
>> > +       dev_pm_opp_put_supported_hw(opp_temp);
>>
>> This is not needed because dev_pm_opp_set_supported_hw will free
>> memory in case of failure. This call in only needed in case of a
>> successful get.
>
> But this is still required for the case where platform device
> registration fails.

Agreed. The overall error path needs to be re-written with proper
check of return values.