linux-kernel - Re: [PATCH v3 RESEND 3/6] bitmap: Make bitmap

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Date: Mon, 12 Feb 2024 16:36:36 +0200
From: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To: Herve Codina <herve.codina@...tlin.com>
Cc: Vadim Fedorenko <vadim.fedorenko@...ux.dev>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
	Yury Norov <yury.norov@...il.com>,
	Rasmus Villemoes <linux@...musvillemoes.dk>,
	linux-kernel@...r.kernel.org, netdev@...r.kernel.org,
	linuxppc-dev@...ts.ozlabs.org, Andrew Lunn <andrew@...n.ch>,
	Mark Brown <broonie@...nel.org>,
	Christophe Leroy <christophe.leroy@...roup.eu>,
	Thomas Petazzoni <thomas.petazzoni@...tlin.com>
Subject: Re: [PATCH v3 RESEND 3/6] bitmap: Make bitmap_onto() available to
 users

On Mon, Feb 12, 2024 at 03:20:22PM +0100, Herve Codina wrote:
> On Mon, 12 Feb 2024 16:01:38 +0200
> Andy Shevchenko <andriy.shevchenko@...ux.intel.com> wrote:

..

> Agree, the bitmap_onto() code is simpler to understand than its help.
> 
> I introduced bitmap_off() to be the "reverse" bitmap_onto() operations
> and I preferred to avoid duplicating function that do the same things.
> 
> On my side, I initially didn't use the bitmap_*() functions and did the the
> bits manipulation by hand.
> During the review, it was suggested to use the bitmap_*() family and I followed
> this suggestion.

I also would go this way, the problems I see with the current implementation are:
- being related to NUMA (and as Rasmus once pointed out better to be there);
- unclear naming, esp. proposed bitmap_off();
- the quite hard to understand help text
- atomicity when it's not needed (AFAICT).

> I did tests to be sure that bitmap_onto() and bitmap_off() did
> exactly the same things as my previous code did.

Yuri, what do you think about all this?

-- 
With Best Regards,
Andy Shevchenko