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From: Vincent Mailhol <mailhol@kernel.org>
To: Nathan Chancellor <nathan@kernel.org>,
	Nicolas Schier <nsc@kernel.org>,
	 Nick Desaulniers <nick.desaulniers+lkml@gmail.com>,
	 Bill Wendling <morbo@google.com>,
	Justin Stitt <justinstitt@google.com>,
	 Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
	 Maxime Ripard <mripard@kernel.org>,
	Thomas Zimmermann <tzimmermann@suse.de>,
	 David Airlie <airlied@gmail.com>,
	Simona Vetter <simona@ffwll.ch>,  Chris Mason <clm@fb.com>,
	David Sterba <dsterba@suse.com>,  Kees Cook <kees@kernel.org>,
	"Gustavo A. R. Silva" <gustavoars@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	 linux-kbuild@vger.kernel.org, linux-sparse@vger.kernel.org,
	 linux-kernel@vger.kernel.org, llvm@lists.linux.dev,
	 dri-devel@lists.freedesktop.org, linux-btrfs@vger.kernel.org,
	 linux-hardening@vger.kernel.org,
	Vincent Mailhol <mailhol@kernel.org>
Subject: [PATCH v3 3/3] overflow: Remove is_non_negative() and is_negative()
Date: Sat, 20 Dec 2025 12:02:21 +0100	[thread overview]
Message-ID: <20251220-remove_wtype-limits-v3-3-24b170af700e@kernel.org> (raw)
In-Reply-To: <20251220-remove_wtype-limits-v3-0-24b170af700e@kernel.org>

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


  parent reply	other threads:[~2025-12-20 11:03 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-12-20 11:02 [PATCH v3 0/3] kbuild: remove gcc's -Wtype-limits Vincent Mailhol
2025-12-20 11:02 ` [PATCH v3 1/3] " Vincent Mailhol
2025-12-20 11:02 ` [PATCH v3 2/3] kbuild: cleanup local -Wno-type-limits exceptions Vincent Mailhol
2025-12-20 12:53   ` Nicolas Schier
2025-12-20 11:02 ` Vincent Mailhol [this message]
2025-12-20 12:52   ` [PATCH v3 3/3] overflow: Remove is_non_negative() and is_negative() Nicolas Schier
2025-12-22 10:03   ` kernel test robot
2025-12-22 18:39     ` Vincent Mailhol
2025-12-22 19:55   ` kernel test robot
2025-12-25  6:04   ` kernel test robot
2025-12-27  8:49   ` kernel test robot
2025-12-28  1:41   ` kernel test robot
2026-01-01 15:10   ` Vincent Mailhol
2026-01-01 19:39     ` Nicolas Schier
2026-01-02 11:04       ` Miguel Ojeda
2026-01-02 22:26         ` Vincent Mailhol
2026-01-02 22:29           ` [PATCH] overflow: Update is_non_negative() and is_negative() comment Vincent Mailhol
2026-01-03 10:02             ` Dan Carpenter
2026-01-03 11:10               ` Vincent Mailhol
2026-01-03 16:56                 ` Dan Carpenter
2026-01-03 19:40                   ` Vincent Mailhol
2026-01-05  7:26                     ` Dan Carpenter
2026-01-05 23:56 ` [PATCH v3 0/3] kbuild: remove gcc's -Wtype-limits Nathan Chancellor

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