linux-kernel - [PATCH next 4/7] minmax.h: Use BUILD_BUG_ON

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Message-ID: <34d53778977747f19cce2abb287bb3e6@AcuMS.aculab.com>
Date: Mon, 18 Nov 2024 19:13:31 +0000
From: David Laight <David.Laight@...LAB.COM>
To: Linus Torvalds <torvalds@...ux-foundation.org>
CC: 'Arnd Bergmann' <arnd@...nel.org>, "'linux-kernel@...r.kernel.org'"
	<linux-kernel@...r.kernel.org>, 'Jens Axboe' <axboe@...nel.dk>, "'Matthew
 Wilcox'" <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>, "'Jason A . Donenfeld'" <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: [PATCH next 4/7] minmax.h: Use BUILD_BUG_ON_MSG() for the lo < hi
 test in clamp()

Use BUILD_BUG_ON_MSG(statically_true(ulo > uhi), ...) for the sanity
check of the bounds in clamp().
Gives better error coverage and one less expansion of the arguments.

Signed-off-by: David Laight <david.laight@...lab.com>
---
 include/linux/minmax.h | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/include/linux/minmax.h b/include/linux/minmax.h
index 6f7ea669d305..91aa1b90c1bb 100644
--- a/include/linux/minmax.h
+++ b/include/linux/minmax.h
@@ -106,8 +106,7 @@
 	__auto_type uval = (val);						\
 	__auto_type ulo = (lo);							\
 	__auto_type uhi = (hi);							\
-	static_assert(__builtin_choose_expr(__is_constexpr((lo) > (hi)), 	\
-			(lo) <= (hi), true),					\
+	BUILD_BUG_ON_MSG(statically_true(ulo > uhi),				\
 		"clamp() low limit " #lo " greater than high limit " #hi);	\
 	BUILD_BUG_ON_MSG(!__types_ok3(uval, ulo, uhi),				\
 		"clamp("#val", "#lo", "#hi") signedness error");		\
-- 
2.17.1

-
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