Re: arm64: csum: Add fused copy and Internet checksum

[kernel test robot <lkp@intel.com>]

Unfiltered warning: this smatch report is sent as-is and has not been
reviewed for false positives, so please treat it with due skepticism.

BCC: lkp@intel.com
CC: oe-kbuild-all@lists.linux.dev
In-Reply-To: <202610051422.TPjuBOMt-lkp@intel.com>
References: <202610051422.TPjuBOMt-lkp@intel.com>

Hi Demian,

kernel test robot noticed the following build warnings:



url:    https://github.com/intel-lab-lkp/linux/commits/Demian-Shulhan/arm64-csum-Add-fused-copy-and-Internet-checksum/20260927-151757
base:   
patch link:    https://lore.kernel.org/r/202610051422.TPjuBOMt-lkp%40intel.com
:::::: branch date: 8 days ago
:::::: commit date: 8 days ago
config: arm64-randconfig-r2200-20261003 (https://download.01.org/0day-ci/archive/20261005/202610051422.TPjuBOMt-lkp@intel.com/config)
compiler: aarch64-linux-gcc (GCC) 16.1.0
smatch: v0.5.0-9187-g5189e3fb

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@intel.com>
| Reported-by: Dan Carpenter <error27@gmail.com>
| Closes: https://lore.kernel.org/r/202610051422.TPjuBOMt-lkp@intel.com/

New smatch warnings:
arch/arm64/lib/csum-copy-neon.c:93 (null)() warn: statement has no effect 'uint8x16_t'

Old smatch warnings:
arch/arm64/lib/csum-copy-neon.c:103 (null)() warn: statement has no effect 'uint8x16_t'

vim +/uint8x16_t +93 arch/arm64/lib/csum-copy-neon.c

15b4870d68269b Demian Shulhan 2026-09-27  81  
15b4870d68269b Demian Shulhan 2026-09-27  82  __wsum __csum_partial_copy_neon(const void *src, void *dst, int len)
15b4870d68269b Demian Shulhan 2026-09-27  83  {
15b4870d68269b Demian Shulhan 2026-09-27  84  	const u8 *s = src;
15b4870d68269b Demian Shulhan 2026-09-27  85  	u8 *d = dst;
15b4870d68269b Demian Shulhan 2026-09-27  86  	uint64x2_t acc0 = { }, acc1 = { };
15b4870d68269b Demian Shulhan 2026-09-27  87  	unsigned int head = -(unsigned long)d & 15;
15b4870d68269b Demian Shulhan 2026-09-27  88  	unsigned int tail = (len - head) & 15;
15b4870d68269b Demian Shulhan 2026-09-27  89  	u32 sum;
15b4870d68269b Demian Shulhan 2026-09-27  90  
15b4870d68269b Demian Shulhan 2026-09-27  91  	if (tail) {
15b4870d68269b Demian Shulhan 2026-09-27  92  		/* Final vector, ending exactly at the buffer end; see above */
15b4870d68269b Demian Shulhan 2026-09-27 @93  		uint8x16_t v = vld1q_u8(s + len - 16);

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