linux-kernel - Re: [PATCH next 6/7] minmax.h: Simplify the variants of clamp()

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Message-ID: <202411230458.dhZwh3TT-lkp@intel.com>
Date: Sat, 23 Nov 2024 04:20:02 +0800
From: kernel test robot <lkp@...el.com>
To: David Laight <David.Laight@...lab.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>
Cc: oe-kbuild-all@...ts.linux.dev, LKML <linux-kernel@...r.kernel.org>,
	'Arnd Bergmann' <arnd@...nel.org>, 'Jens Axboe' <axboe@...nel.dk>,
	'Matthew Wilcox' <willy@...radead.org>,
	'Christoph Hellwig' <hch@...radead.org>,
	'Andrew Morton' <akpm@...ux-foundation.org>,
	Linux Memory Management List <linux-mm@...ck.org>,
	'Andy Shevchenko' <andriy.shevchenko@...ux.intel.com>,
	'Dan Carpenter' <dan.carpenter@...aro.org>,
	"'Jason A . Donenfeld'" <Jason@...c4.com>,
	"'pedro.falcato@...il.com'" <pedro.falcato@...il.com>,
	'Mateusz Guzik' <mjguzik@...il.com>,
	'Lorenzo Stoakes' <lorenzo.stoakes@...cle.com>
Subject: Re: [PATCH next 6/7] minmax.h: Simplify the variants of clamp()

Hi David,

kernel test robot noticed the following build warnings:

[auto build test WARNING on next-20241121]

url:    https://github.com/intel-lab-lkp/linux/commits/David-Laight/minmax-h-Add-whitespace-around-operators-and-after-commas/20241121-152617
base:   next-20241121
patch link:    https://lore.kernel.org/r/8f69f4deac014f558bab186444bac2e8%40AcuMS.aculab.com
patch subject: [PATCH next 6/7] minmax.h: Simplify the variants of clamp()
config: loongarch-allyesconfig (https://download.01.org/0day-ci/archive/20241123/202411230458.dhZwh3TT-lkp@intel.com/config)
compiler: loongarch64-linux-gcc (GCC) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241123/202411230458.dhZwh3TT-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@...el.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202411230458.dhZwh3TT-lkp@intel.com/

All warnings (new ones prefixed by >>):

   In file included from include/linux/kernel.h:28,
                    from include/linux/cpumask.h:11,
                    from arch/loongarch/include/asm/processor.h:9,
                    from arch/loongarch/include/asm/thread_info.h:15,
                    from include/linux/thread_info.h:60,
                    from include/asm-generic/current.h:6,
                    from ./arch/loongarch/include/generated/asm/current.h:1,
                    from include/linux/sched.h:12,
                    from include/linux/delay.h:13,
                    from drivers/iio/magnetometer/yamaha-yas530.c:27:
   drivers/iio/magnetometer/yamaha-yas530.c: In function 'yas537_measure':
>> include/linux/minmax.h:188:20: warning: overflow in conversion from 'long unsigned int' to 's32' {aka 'int'} changes value from '18446744073709543424' to '-8192' [-Woverflow]
     188 |         type ulo = (lo);                                                        \
         |                    ^
   include/linux/minmax.h:197:9: note: in expansion of macro '__clamp_once'
     197 |         __clamp_once(type, val, lo, hi, __UNIQUE_ID(v_), __UNIQUE_ID(l_), __UNIQUE_ID(h_))
         |         ^~~~~~~~~~~~
   include/linux/minmax.h:233:32: note: in expansion of macro '__careful_clamp'
     233 | #define clamp_val(val, lo, hi) __careful_clamp(typeof(val), val, lo, hi)
         |                                ^~~~~~~~~~~~~~~
   drivers/iio/magnetometer/yamaha-yas530.c:414:25: note: in expansion of macro 'clamp_val'
     414 |                         clamp_val(h[i], -BIT(13), BIT(13) - 1);
         |                         ^~~~~~~~~


vim +188 include/linux/minmax.h

   172	
   173	/**
   174	 * min_not_zero - return the minimum that is _not_ zero, unless both are zero
   175	 * @x: value1
   176	 * @y: value2
   177	 */
   178	#define min_not_zero(x, y) ({			\
   179		typeof(x) __x = (x);			\
   180		typeof(y) __y = (y);			\
   181		__x == 0 ? __y : ((__y == 0) ? __x : min(__x, __y)); })
   182	
   183	#define __clamp(val, lo, hi)	\
   184		((val) >= (hi) ? (hi) : ((val) <= (lo) ? (lo) : (val)))
   185	
   186	#define __clamp_once(type, val, lo, hi, uval, ulo, uhi) ({			\
   187		type uval = (val);							\
 > 188		type ulo = (lo);							\
   189		type uhi = (hi);							\
   190		BUILD_BUG_ON_MSG(statically_true(ulo > uhi),				\
   191			"clamp() low limit " #lo " greater than high limit " #hi);	\
   192		BUILD_BUG_ON_MSG(!__types_ok3(uval, ulo, uhi),				\
   193			"clamp("#val", "#lo", "#hi") signedness error");		\
   194		__clamp(uval, ulo, uhi); })
   195	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki