netdev - [PATCH next v2 06/11] minmax: Remove 'constexpr' check from __careful

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: <c91f7fb1f5104a57af820e955c254249@AcuMS.aculab.com>
Date: Sun, 25 Feb 2024 16:52:22 +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: 'Jens Axboe' <axboe@...nel.dk>, "'Matthew Wilcox (Oracle)'"
	<willy@...radead.org>, 'Christoph Hellwig' <hch@...radead.org>,
	"'linux-btrfs@...r.kernel.org'" <linux-btrfs@...r.kernel.org>, "'Andrew
 Morton'" <akpm@...ux-foundation.org>, 'Andy Shevchenko'
	<andriy.shevchenko@...ux.intel.com>, "'David S . Miller'"
	<davem@...emloft.net>, 'Dan Carpenter' <dan.carpenter@...aro.org>, "'Jani
 Nikula'" <jani.nikula@...ux.intel.com>
Subject: [PATCH next v2 06/11] minmax: Remove 'constexpr' check from
 __careful_clamp()

Nothing requires that clamp() return a constant expression.
The logic to do so significantly increases the .i file.
Remove the check and directly expand __clamp_once() from clamp_t()
since the type check can't fail.

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

Changes for v2:
- Typographical and spelling corrections to the commit messages.
  Patches unchanged.

diff --git a/include/linux/minmax.h b/include/linux/minmax.h
index 111c52a14fe5..5c7fce76abe5 100644
--- a/include/linux/minmax.h
+++ b/include/linux/minmax.h
@@ -141,12 +141,10 @@
 		"clamp() low limit " #lo " greater than high limit " #hi);	\
 	__clamp(__val_##uniq, __lo_##uniq, __hi_##uniq); })
 
-#define __careful_clamp(val, lo, hi, uniq)				\
-	__builtin_choose_expr(__is_constexpr((val) - (lo) + (hi)),	\
-		__clamp(val, lo, hi),					\
-		({ _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); }))
+#define __careful_clamp(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
@@ -168,7 +166,9 @@
  * This macro does no typechecking and uses temporary variables of type
  * @type to make all the comparisons.
  */
-#define clamp_t(type, val, lo, hi) clamp((type)(val), (type)(lo), (type)(hi))
+#define __clamp_t(type, val, lo, hi, uniq) \
+	__clamp_once((type)(val), (type)(lo), (type)(hi), uniq)
+#define clamp_t(type, val, lo, hi) __clamp_t(type, val, lo, hi, __COUNTER__)
 
 /**
  * clamp_val - return a value clamped to a given range using val's type
-- 
2.17.1

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