linux-kernel - RE: [PATCH next 05/11] minmax: Move the signedness check out of __cmp_once() and __clamp

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Message-ID: <a6b280993ac5448fa75f226262893f89@AcuMS.aculab.com>
Date: Sun, 28 Jan 2024 19:29:45 +0000
From: David Laight <David.Laight@...LAB.COM>
To: "'linux-kernel@...r.kernel.org'" <linux-kernel@...r.kernel.org>, "'Linus
 Torvalds'" <torvalds@...ux-foundation.org>, 'Netdev'
	<netdev@...r.kernel.org>, "'dri-devel@...ts.freedesktop.org'"
	<dri-devel@...ts.freedesktop.org>
CC: 'Andy Shevchenko' <andriy.shevchenko@...ux.intel.com>, 'Andrew Morton'
	<akpm@...ux-foundation.org>, "'Matthew Wilcox (Oracle)'"
	<willy@...radead.org>, 'Christoph Hellwig' <hch@...radead.org>, "'Dan
 Carpenter'" <dan.carpenter@...aro.org>, 'Linus Walleij'
	<linus.walleij@...aro.org>, "'David S . Miller'" <davem@...emloft.net>,
	"'linux-btrfs@...r.kernel.org'" <linux-btrfs@...r.kernel.org>, 'Jens Axboe'
	<axboe@...nel.dk>
Subject: RE: [PATCH next 05/11] minmax: Move the signedness check out of
 __cmp_once() and __clamp_once()

There is no need to do the signedness/type check when the arguments
are being cast to a fixed type.
So move the check out of __xxx_once() into __careful_xxx().

Signed-off-by: David Laight <david.laight@...lab.com>
---
 include/linux/minmax.h | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/include/linux/minmax.h b/include/linux/minmax.h
index 8ee003d8abaf..111c52a14fe5 100644
--- a/include/linux/minmax.h
+++ b/include/linux/minmax.h
@@ -46,14 +46,14 @@
 #define __cmp_once(op, x, y, uniq) ({		\
 	typeof(x) __x_##uniq = (x);		\
 	typeof(y) __y_##uniq = (y);		\
-	_Static_assert(__types_ok(x, y),	\
-		#op "(" #x ", " #y ") signedness error, fix types or consider u" #op "() before " #op "_t()"); \
 	__cmp(op, __x_##uniq, __y_##uniq); })
 
 #define __careful_cmp(op, x, y, uniq)				\
 	__builtin_choose_expr(__is_constexpr((x) - (y)),	\
 		__cmp(op, x, y),				\
-		__cmp_once(op, x, y, uniq))
+		({ _Static_assert(__types_ok(x, y),		\
+			#op "(" #x ", " #y ") signedness error, fix types or consider u" #op "() before " #op "_t()"); \
+		__cmp_once(op, x, y, uniq); }))
 
 /**
  * min - return minimum of two values of the same or compatible types
@@ -139,14 +139,14 @@
 	_Static_assert(__builtin_choose_expr(__is_constexpr((lo) > (hi)),	\
 			(lo) <= (hi), true),					\
 		"clamp() low limit " #lo " greater than high limit " #hi);	\
-	_Static_assert(__types_ok(val, lo), "clamp() 'lo' signedness error");	\
-	_Static_assert(__types_ok(val, hi), "clamp() 'hi' signedness error");	\
 	__clamp(__val_##uniq, __lo_##uniq, __hi_##uniq); })
 
-#define __careful_clamp(val, lo, hi, uniq) ({				\
+#define __careful_clamp(val, lo, hi, uniq)				\
 	__builtin_choose_expr(__is_constexpr((val) - (lo) + (hi)),	\
 		__clamp(val, lo, hi),					\
-		__clamp_once(val, lo, hi, uniq)); })
+		({ _Static_assert(__types_ok(val, lo), "clamp() 'lo' signedness error");	\
+		_Static_assert(__types_ok(val, hi), "clamp() 'hi' signedness error");	\
+		__clamp_once(val, lo, hi, uniq); }))
 
 /**
  * clamp - return a value clamped to a given range with strict typechecking
-- 
2.17.1

-
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