linux-kernel - Re: [PATCH v4 next 0/9] Implement mul_u64_u64_div_u64

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Message-ID: <20251031135255.GA22251@redhat.com>
Date: Fri, 31 Oct 2025 14:52:56 +0100
From: Oleg Nesterov <oleg@...hat.com>
To: David Laight <david.laight.linux@...il.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>, linux-kernel@...r.kernel.org,
	u.kleine-koenig@...libre.com, Nicolas Pitre <npitre@...libre.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Biju Das <biju.das.jz@...renesas.com>,
	Borislav Petkov <bp@...en8.de>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	"H. Peter Anvin" <hpa@...or.com>, Ingo Molnar <mingo@...hat.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Li RongQing <lirongqing@...du.com>, Yu Kuai <yukuai3@...wei.com>,
	Khazhismel Kumykov <khazhy@...omium.org>,
	Jens Axboe <axboe@...nel.dk>, x86@...nel.org
Subject: Re: [PATCH v4 next 0/9] Implement mul_u64_u64_div_u64_roundup()

On 10/29, David Laight wrote:
>
> The pwm-stm32.c code wants a 'rounding up' version of mul_u64_u64_div_u64().
> This can be done simply by adding 'divisor - 1' to the 128bit product.
> Implement mul_u64_add_u64_div_u64(a, b, c, d) = (a * b + c)/d based on the
> existing code.
> Define mul_u64_u64_div_u64(a, b, d) as mul_u64_add_u64_div_u64(a, b, 0, d) and
> mul_u64_u64_div_u64_roundup(a, b, d) as mul_u64_add_u64_div_u64(a, b, d-1, d).

Sorry for the noise. Can't review due to the lack of knowledge.
But this reminds me... What about

	[PATCH v3 1/2] x86/math64: handle #DE in mul_u64_u64_div_u64()
	https://lore.kernel.org/all/20250815164055.GA13444@redhat.com

?

should I resend it once again or we don't care?

Oleg.