linux-kernel - [PATCH v3 3/3] overflow: Remove is_non_negative() and is

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Message-Id: <20251220-remove_wtype-limits-v3-3-24b170af700e@kernel.org>
Date: Sat, 20 Dec 2025 12:02:21 +0100
From: Vincent Mailhol <mailhol@...nel.org>
To: Nathan Chancellor <nathan@...nel.org>, Nicolas Schier <nsc@...nel.org>, 
 Nick Desaulniers <nick.desaulniers+lkml@...il.com>, 
 Bill Wendling <morbo@...gle.com>, Justin Stitt <justinstitt@...gle.com>, 
 Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, 
 Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>, 
 David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>, 
 Chris Mason <clm@...com>, David Sterba <dsterba@...e.com>, 
 Kees Cook <kees@...nel.org>, "Gustavo A. R. Silva" <gustavoars@...nel.org>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>, 
 linux-kbuild@...r.kernel.org, linux-sparse@...r.kernel.org, 
 linux-kernel@...r.kernel.org, llvm@...ts.linux.dev, 
 dri-devel@...ts.freedesktop.org, linux-btrfs@...r.kernel.org, 
 linux-hardening@...r.kernel.org, Vincent Mailhol <mailhol@...nel.org>
Subject: [PATCH v3 3/3] overflow: Remove is_non_negative() and
 is_negative()

The is_non_negative() and is_negative() function-like macros just
exist as a workaround to silence the -Wtype-limits warning. Now that
this warning is disabled, those two macros have lost their raison
d'être. Remove them.

This reverts commit dc7fe518b049 ("overflow: Fix -Wtype-limits
compilation warnings").

Suggested-by: Nicolas Schier <nsc@...nel.org>
Link: https://lore.kernel.org/all/aUT_yWin_xslnOFh@derry.ads.avm.de
Signed-off-by: Vincent Mailhol <mailhol@...nel.org>
---
Changelog:

  v1 -> v2: new patch
---
 include/linux/overflow.h | 10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/include/linux/overflow.h b/include/linux/overflow.h
index 736f633b2d5f..ab142d60c6b5 100644
--- a/include/linux/overflow.h
+++ b/include/linux/overflow.h
@@ -36,12 +36,6 @@
 #define __type_min(T) ((T)((T)-type_max(T)-(T)1))
 #define type_min(t)	__type_min(typeof(t))

-/*
- * Avoids triggering -Wtype-limits compilation warning,
- * while using unsigned data types to check a < 0.
- */
-#define is_non_negative(a) ((a) > 0 || (a) == 0)
-#define is_negative(a) (!(is_non_negative(a)))

 /*
  * Allows for effectively applying __must_check to a macro so we can have
@@ -201,9 +195,9 @@ static inline bool __must_check __must_check_overflow(bool overflow)
 	typeof(d) _d = d;						\
 	unsigned long long _a_full = _a;				\
 	unsigned int _to_shift =					\
-		is_non_negative(_s) && _s < 8 * sizeof(*d) ? _s : 0;	\
+		_s >= 0 && _s < 8 * sizeof(*d) ? _s : 0;		\
 	*_d = (_a_full << _to_shift);					\
-	(_to_shift != _s || is_negative(*_d) || is_negative(_a) ||	\
+	(_to_shift != _s || *_d < 0 || _a < 0 ||			\
 	(*_d >> _to_shift) != _a);					\
 }))

-- 
2.51.2