linux-kernel - Re: [PATCH] x86/tsc: Replace do_div() with div64_u64()/div64

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Message-ID: <c6eb6734-93d3-4a59-8869-49ecc438fff9@linuxfoundation.org>
Date: Thu, 24 Jul 2025 16:32:43 -0600
From: Shuah Khan <skhan@...uxfoundation.org>
To: Niko Nikolov <nikolay.niko.nikolov@...il.com>, shuah@...nel.org,
 linux-kernel@...r.kernel.org
Cc: Shuah Khan <skhan@...uxfoundation.org>
Subject: Re: [PATCH] x86/tsc: Replace do_div() with div64_u64()/div64_ul()

On 7/24/25 15:53, Niko Nikolov wrote:
> Replace do_div() with the recommended division helpers to avoid
> truncation and follow kernel best practices, as flagged by static
> analysis.

You are making more changes than what change log indicates.

> 
> ./arch/x86/kernel/tsc.c:409:1-7:
> WARNING: do_div() does a 64-by-32 division, please consider using div64_u64 instead.
> ./arch/x86/kernel/tsc.c:492:1-7:
> WARNING: do_div() does a 64-by-32 division, please consider using div64_ul instead.
> ./arch/x86/kernel/tsc.c:831:2-8:
> WARNING: do_div() does a 64-by-32 division, please consider using div64_ul instead.

It is hard to see where you are addressing the above warnings with all
the other changes.

Also you don't have the right reviewers cc'ed

> 
> Signed-off-by: Niko Nikolov <nikolay.niko.nikolov@...il.com>
> ---
>   arch/x86/kernel/tsc.c | 185 +++++++++++++++++++++---------------------
>   1 file changed, 91 insertions(+), 94 deletions(-)
> 
> diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
> index 87e749106dda..96f40759340e 100644
> --- a/arch/x86/kernel/tsc.c
> +++ b/arch/x86/kernel/tsc.c
> @@ -34,13 +34,13 @@
>   #include <asm/uv/uv.h>
>   #include <asm/sev.h>
>   
> -unsigned int __read_mostly cpu_khz;	/* TSC clocks / usec, not used here */
> +unsigned int __read_mostly cpu_khz; /* TSC clocks / usec, not used here */
>   EXPORT_SYMBOL(cpu_khz);
>   
>   unsigned int __read_mostly tsc_khz;
>   EXPORT_SYMBOL(tsc_khz);
>   
> -#define KHZ	1000
> +#define KHZ 1000

What changed here?

>   
>   /*
>    * TSC can be unstable due to cpufreq or due to unsynced TSCs
> @@ -55,13 +55,13 @@ int tsc_clocksource_reliable;
>   static int __read_mostly tsc_force_recalibrate;
>   
>   static struct clocksource_base art_base_clk = {
> -	.id    = CSID_X86_ART,
> +	.id = CSID_X86_ART,

Tabs removed? Why?

>   };
>   static bool have_art;
>   

Same questions for the rest of the format changes.

thanks,
-- Shuah