linux-kernel - Re: [PATCH v7 6/8] math.h Add macros to round to closest specified power of 2

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Message-ID: <Zj42vTpyH71TWeTk@smile.fi.intel.com>
Date: Fri, 10 May 2024 18:01:17 +0300
From: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To: Devarsh Thakkar <devarsht@...com>
Cc: mchehab@...nel.org, hverkuil-cisco@...all.nl,
	linux-media@...r.kernel.org, linux-kernel@...r.kernel.org,
	benjamin.gaignard@...labora.com, sebastian.fricke@...labora.com,
	akpm@...ux-foundation.org, gregkh@...uxfoundation.org,
	adobriyan@...il.com, jani.nikula@...el.com, p.zabel@...gutronix.de,
	airlied@...il.com, daniel@...ll.ch, dri-devel@...ts.freedesktop.org,
	laurent.pinchart@...asonboard.com, praneeth@...com, nm@...com,
	vigneshr@...com, a-bhatia1@...com, j-luthra@...com, b-brnich@...com,
	detheridge@...com, p-mantena@...com, vijayp@...com,
	andrzej.p@...labora.com, nicolas@...fresne.ca
Subject: Re: [PATCH v7 6/8] math.h Add macros to round to closest specified
 power of 2

On Fri, May 10, 2024 at 12:09:52AM +0530, Devarsh Thakkar wrote:
> Add macros to round to nearest specified power of 2.

This is not what they are doing. For the above we already have macros defined.

> Two macros are added :

(Yes, after I wrapped to comment this line looks better on its own,
 so whatever will be the first sentence, this line should be separated
 from.)

> round_closest_up and round_closest_down which round up to nearest multiple

round_closest_up() and round_closest_down()


> of 2 with a preference to round up or round down respectively if there are
> two possible nearest values to the given number.

You should reformulate, because AFAICS there is the crucial difference
from these and existing round_*_pow_of_two().

> This patch is inspired from the Mentor Graphics IPU driver [1] which uses
> similar macro locally and which can be updated to use this generic macro
> instead along with other drivers having similar requirements.
> 
> [1]:
> https://elixir.bootlin.com/linux/v6.8.9/source/drivers/gpu/ipu-v3/ipu-image-convert.c#L480

Instead of this, just add a patch to convert that driver to use this new macro.
Besides, this paragraph should go to the comment/changelog area below.

> Signed-off-by: Devarsh Thakkar <devarsht@...com>
> ---
> V1->V6 (No change, patch introduced in V7)
> ---

-- 
With Best Regards,
Andy Shevchenko