linux-kernel - [PATCH 6/7 5.10.y] minmax: allow comparisons of 'int' against 'unsigned char/short'

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Message-ID: <20250916213149.9637-1-farbere@amazon.com>
Date: Tue, 16 Sep 2025 21:31:49 +0000
From: Eliav Farber <farbere@...zon.com>
To: <luc.vanoostenryck@...il.com>, <rostedt@...dmis.org>, <mingo@...hat.com>,
	<akpm@...ux-foundation.org>, <gregkh@...uxfoundation.org>, <sj@...nel.org>,
	<David.Laight@...LAB.COM>, <Jason@...c4.com>,
	<andriy.shevchenko@...ux.intel.com>, <bvanassche@....org>,
	<keescook@...omium.org>, <linux-sparse@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>
CC: <jonnyc@...zon.com>, <farbere@...zon.com>, <stable@...r.kernel.org>,
	Christoph Hellwig <hch@...radead.org>, Linus Torvalds
	<torvalds@...ux-foundation.org>, "Matthew Wilcox (Oracle)"
	<willy@...radead.org>
Subject: [PATCH 6/7 5.10.y] minmax: allow comparisons of 'int' against 'unsigned char/short'

From: David Laight <David.Laight@...LAB.COM>

commit 4ead534fba42fc4fd41163297528d2aa731cd121 upstream.

Since 'unsigned char/short' get promoted to 'signed int' it is safe to
compare them against an 'int' value.

Link: https://lkml.kernel.org/r/8732ef5f809c47c28a7be47c938b28d4@AcuMS.aculab.com
Signed-off-by: David Laight <david.laight@...lab.com>
Cc: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc: Christoph Hellwig <hch@...radead.org>
Cc: Jason A. Donenfeld <Jason@...c4.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Matthew Wilcox (Oracle) <willy@...radead.org>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
(cherry picked from commit 4ead534fba42fc4fd41163297528d2aa731cd121)
Signed-off-by: SeongJae Park <sj@...nel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Signed-off-by: Eliav Farber <farbere@...zon.com>
---
 include/linux/minmax.h | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/include/linux/minmax.h b/include/linux/minmax.h
index 501fab582d68..f76b7145fc11 100644
--- a/include/linux/minmax.h
+++ b/include/linux/minmax.h
@@ -25,8 +25,9 @@
 	__builtin_choose_expr(__is_constexpr(is_signed_type(typeof(x))),	\
 		is_signed_type(typeof(x)), 0)
 
-#define __types_ok(x, y) \
-	(__is_signed(x) == __is_signed(y))
+#define __types_ok(x, y) 			\
+	(__is_signed(x) == __is_signed(y) ||	\
+		__is_signed((x) + 0) == __is_signed((y) + 0))
 
 #define __cmp_op_min <
 #define __cmp_op_max >
-- 
2.47.3