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From: David Laight <David.Laight@ACULAB.COM>
To: 'Linus Torvalds' <torvalds@linuxfoundation.org>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Jens Axboe <axboe@kernel.dk>,
	"Matthew Wilcox (Oracle)" <willy@infradead.org>,
	"Christoph Hellwig" <hch@infradead.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	"Andy Shevchenko" <andriy.shevchenko@linux.intel.com>,
	Dan Carpenter <dan.carpenter@linaro.org>,
	Arnd Bergmann <arnd@kernel.org>,
	"Jason@zx2c4.com" <Jason@zx2c4.com>,
	"pedro.falcato@gmail.com" <pedro.falcato@gmail.com>,
	Mateusz Guzik <mjguzik@gmail.com>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Subject: RE: [PATCH v2 1/8] minmax: Put all the clamp() definitions together
Date: Sun, 28 Jul 2024 20:09:17 +0000	[thread overview]
Message-ID: <e718056c1999497ebf8726af49475701@AcuMS.aculab.com> (raw)
In-Reply-To: <CAHk-=wgH0oETG1eY9WS79aKrPqYZZzfOYxjtgmyr7jH52c8vsg@mail.gmail.com>

From: Linus Torvalds <torvalds@linuxfoundation.org>
> Sent: 28 July 2024 20:55
> 
> On Sun, 28 Jul 2024 at 11:12, David Laight <David.Laight@aculab.com> wrote:
> >
> > Although min_t(type,x,y) should just be
> >         type __x = x;
> >         type __y = y;
> >         __x < __y ? __x : __y;
> > Absolutely no point doing anything else.
> 
> I tried it. Doesn't quite work:
> 
>   net/ipv4/proc.c: In function ‘snmp_seq_show_tcp_udp’:
>   net/ipv4/proc.c:414:9: error: ISO C90 forbids variable length array
> ‘buff’ [-Werror=vla]
>     414 |         unsigned long buff[TCPUDP_MIB_MAX];
>         |         ^~~~~~~~
...

Ah, the constants.
I think they just need to be MIN_CONST() (without the casts).
One might need a cast of one of its constants.
But maybe the signedness test can be ignored if there is a
test for it being a constant.

But (as you said earlier in the year) that should just be MIN().
Except there are a few places that is used that need changing first.

	David

> 
> I guess all of these could just be made to use MIN_T()/MAX_T instead.
> We're not talking hundreds of cases, it seems to be just a small
> handful.
> 
> Let me go check.
> 
>                Linus

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  reply	other threads:[~2024-07-28 20:10 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-07-28 14:15 [PATCH v2 0/8] minmax: reduce compilation time David Laight
2024-07-28 14:17 ` [PATCH v2 1/8] minmax: Put all the clamp() definitions together David Laight
2024-07-28 17:24   ` Linus Torvalds
2024-07-28 18:11     ` David Laight
2024-07-28 19:55       ` Linus Torvalds
2024-07-28 20:09         ` David Laight [this message]
2024-07-28 20:13           ` Linus Torvalds
2024-07-28 20:22             ` David Laight
2024-07-28 20:31               ` Linus Torvalds
2024-07-28 22:13                 ` David Laight
2024-07-28 22:22                   ` Linus Torvalds
2024-07-29  8:01                     ` David Laight
2024-07-28 21:01               ` Linus Torvalds
2024-07-28 21:53                 ` David Laight
2024-07-29  4:15                 ` Linus Torvalds
2024-07-29 22:25             ` Arnd Bergmann
2024-07-29 23:21               ` Linus Torvalds
2024-07-30  1:52                 ` Linus Torvalds
2024-07-30  3:59                 ` Linus Torvalds
2024-07-30 10:10                   ` Arnd Bergmann
2024-07-30 14:14                     ` Arnd Bergmann
2024-07-30 18:02                       ` Linus Torvalds
2024-07-30 19:52                         ` Linus Torvalds
2024-07-30 21:47                           ` David Laight
2024-07-30 22:44                             ` Linus Torvalds
2024-07-30 23:03                               ` Linus Torvalds
2024-07-31  8:09                                 ` David Laight
2024-07-31 10:50                                   ` Arnd Bergmann
2024-07-31 15:38                                   ` Linus Torvalds
2024-07-31 15:56                                     ` David Laight
2024-07-31 16:04                                       ` Linus Torvalds
2024-12-04 13:15                       ` Geert Uytterhoeven
2024-12-04 17:16                         ` David Laight
2024-07-30 16:35                     ` Linus Torvalds
2024-07-30 16:46                       ` Linus Torvalds
2024-07-30 12:03               ` David Laight
2024-07-28 18:23     ` David Laight
2024-07-28 14:18 ` [PATCH v2 2/8] minmax: Use _Static_assert() instead of static_assert() David Laight
2024-07-28 17:51   ` Christophe JAILLET
2024-07-28 18:12     ` David Laight
2024-07-28 14:19 ` [PATCH v2 3/8] compiler.h: Add __if_constexpr(expr, if_const, if_not_const) David Laight
2024-07-28 14:20 ` [PATCH v2 4/8] minmax: Simplify signedness check David Laight
2024-07-28 16:57   ` Linus Torvalds
2024-07-28 18:14     ` David Laight
2024-07-28 20:13       ` David Laight
2024-07-28 14:21 ` [PATCH v2 5/8] minmax: Factor out the zero-extension logic from umin/umax David Laight
2024-07-28 14:22 ` [PATCH v2 6/8] minmax: Optimise _Static_assert() check in clamp() David Laight
2024-07-28 14:23 ` [PATCH v2 7/8] minmax: Use __auto_type David Laight
2024-07-28 16:59   ` Linus Torvalds
2024-07-28 14:24 ` [PATCH v2 8/8] minmax: minmax: Add __types_ok3() and optimise defines with 3 arguments David Laight

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