linux-kernel - RE: [PATCH v2 1/8] minmax: Put all the clamp() definitions together

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <d949045abc78462ab443b38340ce5c20@AcuMS.aculab.com>
Date: Sun, 28 Jul 2024 20:22:48 +0000
From: David Laight <David.Laight@...LAB.COM>
To: 'Linus Torvalds' <torvalds@...uxfoundation.org>
CC: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, Jens Axboe
	<axboe@...nel.dk>, "Matthew Wilcox (Oracle)" <willy@...radead.org>,
	"Christoph Hellwig" <hch@...radead.org>, Andrew Morton
	<akpm@...ux-foundation.org>, "Andy Shevchenko"
	<andriy.shevchenko@...ux.intel.com>, Dan Carpenter
	<dan.carpenter@...aro.org>, Arnd Bergmann <arnd@...nel.org>,
	"Jason@...c4.com" <Jason@...c4.com>, "pedro.falcato@...il.com"
	<pedro.falcato@...il.com>, Mateusz Guzik <mjguzik@...il.com>,
	"linux-mm@...ck.org" <linux-mm@...ck.org>, Lorenzo Stoakes
	<lorenzo.stoakes@...cle.com>
Subject: RE: [PATCH v2 1/8] minmax: Put all the clamp() definitions together

..
> But I'm inclined to just do that too. Bite the bullet, get rid of the
> whole "has to be a C constant expression" pain.

At least you can 'just do it' :-)

IIRC some of the MIN() need to be min() and others are used for
constants so would need an initial #ifndef MIN test to maintain
bisection without having a single patch that changes all the
files at once.

MIN() (and probably your MIN_T()) ought to have a check for
being a constant in order to stop misuse.
Perhaps just:
#define MIN(x,y) \
	(__builtin_choose_expr((x)+(y), 0, 0) + ((x) < (y} ? (x) : (y)))

	David

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)