linux-kernel - Re: [PATCH] cpufreq: cached_resolved

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Message-ID: <CAHLCerP4YPHc4sKD_RTq=Gxfj+ex4F=J2is1Y-UzGXcOuEOrOQ@mail.gmail.com>
Date:   Thu, 30 Jul 2020 11:29:38 +0530
From:   Amit Kucheria <amitk@...nel.org>
To:     Viresh Kumar <viresh.kumar@...aro.org>
Cc:     Rafael Wysocki <rjw@...ysocki.net>, Andy Gross <agross@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Linux PM list <linux-pm@...r.kernel.org>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        ionela.voinescu@....com,
        linux-arm-msm <linux-arm-msm@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] cpufreq: cached_resolved_idx can not be negative

On Thu, Jul 30, 2020 at 9:38 AM Viresh Kumar <viresh.kumar@...aro.org> wrote:
>
> It is not possible for cached_resolved_idx to be invalid here as the
> cpufreq core always sets index to a positive value.
>
> Change its type to unsigned int and fix qcom usage a bit.

Shouldn't you fix up idx in cpufreq_driver_resolve_freq() to be
unsigned int too?

> Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
> ---
>  drivers/cpufreq/qcom-cpufreq-hw.c | 5 +----
>  include/linux/cpufreq.h           | 2 +-
>  2 files changed, 2 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/cpufreq/qcom-cpufreq-hw.c b/drivers/cpufreq/qcom-cpufreq-hw.c
> index 0a04b6f03b9a..8c0842bd6c5a 100644
> --- a/drivers/cpufreq/qcom-cpufreq-hw.c
> +++ b/drivers/cpufreq/qcom-cpufreq-hw.c
> @@ -66,13 +66,10 @@ static unsigned int qcom_cpufreq_hw_fast_switch(struct cpufreq_policy *policy,
>                                                 unsigned int target_freq)
>  {
>         void __iomem *perf_state_reg = policy->driver_data;
> -       int index;
> +       unsigned int index;
>         unsigned long freq;
>
>         index = policy->cached_resolved_idx;
> -       if (index < 0)
> -               return 0;
> -
>         writel_relaxed(index, perf_state_reg);
>
>         freq = policy->freq_table[index].frequency;
> diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
> index e62b022cb07e..58687a5bf9c8 100644
> --- a/include/linux/cpufreq.h
> +++ b/include/linux/cpufreq.h
> @@ -127,7 +127,7 @@ struct cpufreq_policy {
>
>          /* Cached frequency lookup from cpufreq_driver_resolve_freq. */
>         unsigned int cached_target_freq;
> -       int cached_resolved_idx;
> +       unsigned int cached_resolved_idx;
>
>         /* Synchronization for frequency transitions */
>         bool                    transition_ongoing; /* Tracks transition status */
> --
> 2.14.1
>