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From:   Punit Agrawal <punit.agrawal@bytedance.com>
To:     Perry Yuan <Perry.Yuan@amd.com>
Cc:     <rafael.j.wysocki@intel.com>, <ray.huang@amd.com>,
        <viresh.kumar@linaro.org>, <Deepak.Sharma@amd.com>,
        <Mario.Limonciello@amd.com>, <Nathan.Fontenot@amd.com>,
        <Alexander.Deucher@amd.com>, <Jinzhou.Su@amd.com>,
        <Shimmer.Huang@amd.com>, <Xiaojian.Du@amd.com>, <Li.Meng@amd.com>,
        <linux-pm@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v5 1/7] cpufreq: amd-pstate: cleanup the unused and
 duplicated headers declaration
References: <20220814163548.326686-1-Perry.Yuan@amd.com>
        <20220814163548.326686-2-Perry.Yuan@amd.com>
Date:   Mon, 15 Aug 2022 16:04:38 +0100
In-Reply-To: <20220814163548.326686-2-Perry.Yuan@amd.com> (Perry Yuan's
        message of "Mon, 15 Aug 2022 00:35:42 +0800")
Message-ID: <87fshxim49.fsf@stealth>
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Hi Perry,

Perry Yuan <Perry.Yuan@amd.com> writes:

> Cleanup the headers declaration which are not used
> actually and some duplicated declaration which is declarated in some
> other headers already, it will help to simplify the header part.

We usually don't get rid of indirectly included headers as long as
definitions from header are used in the code. This avoids problems if
for some reason the included header gets dropped - it'll leave the code
in an uncompilable state.

More below.

>
> Reviewed-by: Huang Rui <ray.huang@amd.com>
> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
> Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
> ---
>  drivers/cpufreq/amd-pstate.c | 5 -----
>  1 file changed, 5 deletions(-)
>
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index 9ac75c1cde9c..19a078e232dd 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -31,19 +31,14 @@
>  #include <linux/compiler.h>
>  #include <linux/dmi.h>
>  #include <linux/slab.h>
> -#include <linux/acpi.h>
>  #include <linux/io.h>
>  #include <linux/delay.h>
>  #include <linux/uaccess.h>
>  #include <linux/static_call.h>
>  
> -#include <acpi/processor.h>
>  #include <acpi/cppc_acpi.h>
>  
>  #include <asm/msr.h>
> -#include <asm/processor.h>

On a quick scan, I noticed that "boot_cpu_data" and "boot_cpu_has()" in
the module init function are defined in "asm/processor.h" that is being
removed here. It may compile for now but makes the code more fragile as
explained above.

Please ensure that only the header files that have no definitions used
in this file (amd-pstate.c) are dropped.

> -#include <asm/cpufeature.h>
> -#include <asm/cpu_device_id.h>
>  #include "amd-pstate-trace.h"
>  
>  #define AMD_PSTATE_TRANSITION_LATENCY	0x20000