linux-kernel - net/netfilter/nft_set_pipapo_avx2.c:1052:17: warning: variable 'lt' set but not used

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Message-ID: <202111170917.jNGscRXs-lkp@intel.com>
Date:   Wed, 17 Nov 2021 09:26:26 +0800
From:   kernel test robot <lkp@...el.com>
To:     Stefano Brivio <sbrivio@...hat.com>
Cc:     llvm@...ts.linux.dev, kbuild-all@...ts.01.org,
        linux-kernel@...r.kernel.org,
        Pablo Neira Ayuso <pablo@...filter.org>
Subject: net/netfilter/nft_set_pipapo_avx2.c:1052:17: warning: variable 'lt'
 set but not used

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   8ab774587903771821b59471cc723bba6d893942
commit: 7400b063969bdca4a06cd97f1294d765c8eecbe1 nft_set_pipapo: Introduce AVX2-based lookup implementation
date:   1 year, 8 months ago
config: x86_64-randconfig-r006-20211116 (attached as .config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project fbe72e41b99dc7994daac300d208a955be3e4a0a)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7400b063969bdca4a06cd97f1294d765c8eecbe1
        git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
        git fetch --no-tags linus master
        git checkout 7400b063969bdca4a06cd97f1294d765c8eecbe1
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 ARCH=x86_64 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@...el.com>

All warnings (new ones prefixed by >>):

>> net/netfilter/nft_set_pipapo_avx2.c:1052:17: warning: variable 'lt' set but not used [-Wunused-but-set-variable]
           unsigned long *lt = f->lt, bsize = f->bsize;
                          ^
   1 warning generated.


vim +/lt +1052 net/netfilter/nft_set_pipapo_avx2.c

  1030	
  1031	/**
  1032	 * nft_pipapo_avx2_lookup_slow() - Fallback function for uncommon field sizes
  1033	 * @map:	Previous match result, used as initial bitmap
  1034	 * @fill:	Destination bitmap to be filled with current match result
  1035	 * @f:		Field, containing lookup and mapping tables
  1036	 * @offset:	Ignore buckets before the given index, no bits are filled there
  1037	 * @pkt:	Packet data, pointer to input nftables register
  1038	 * @first:	If this is the first field, don't source previous result
  1039	 * @last:	Last field: stop at the first match and return bit index
  1040	 *
  1041	 * This function should never be called, but is provided for the case the field
  1042	 * size doesn't match any of the known data types. Matching rate is
  1043	 * substantially lower than AVX2 routines.
  1044	 *
  1045	 * Return: -1 on no match, rule index of match if @last, otherwise first long
  1046	 * word index to be checked next (i.e. first filled word).
  1047	 */
  1048	static int nft_pipapo_avx2_lookup_slow(unsigned long *map, unsigned long *fill,
  1049						struct nft_pipapo_field *f, int offset,
  1050						const u8 *pkt, bool first, bool last)
  1051	{
> 1052		unsigned long *lt = f->lt, bsize = f->bsize;
  1053		int i, ret = -1, b;
  1054	
  1055		lt += offset * NFT_PIPAPO_LONGS_PER_M256;
  1056	
  1057		if (first)
  1058			memset(map, 0xff, bsize * sizeof(*map));
  1059	
  1060		for (i = offset; i < bsize; i++) {
  1061			if (f->bb == 8)
  1062				pipapo_and_field_buckets_8bit(f, map, pkt);
  1063			else
  1064				pipapo_and_field_buckets_4bit(f, map, pkt);
  1065			NFT_PIPAPO_GROUP_BITS_ARE_8_OR_4;
  1066	
  1067			b = pipapo_refill(map, bsize, f->rules, fill, f->mt, last);
  1068	
  1069			if (last)
  1070				return b;
  1071	
  1072			if (ret == -1)
  1073				ret = b / XSAVE_YMM_SIZE;
  1074		}
  1075	
  1076		return ret;
  1077	}
  1078	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

Download attachment ".config.gz" of type "application/gzip" (28251 bytes)