Re: [nf-next PATCH 2/2] netfilter: nf_tables: Annotate reduced expressions

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

Hi Phil,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on nf-next/master]

url:    https://github.com/intel-lab-lkp/linux/commits/Phil-Sutter/nf_tables-Export-rule-optimizer-results-to-user-space/20220512-005642
base:   https://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf-next.git master
config: m68k-allyesconfig (https://download.01.org/0day-ci/archive/20220512/202205120906.nNquMTSm-lkp@intel.com/config)
compiler: m68k-linux-gcc (GCC) 11.3.0
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://github.com/intel-lab-lkp/linux/commit/831b99f09285d0cc3a4fb0fcb6fd7c74aaea988a
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Phil-Sutter/nf_tables-Export-rule-optimizer-results-to-user-space/20220512-005642
        git checkout 831b99f09285d0cc3a4fb0fcb6fd7c74aaea988a
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.3.0 make.cross W=1 O=build_dir ARCH=m68k SHELL=/bin/bash net/netfilter/

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

All warnings (new ones prefixed by >>):

   net/netfilter/nft_bitwise.c: In function 'nft_bitwise_reduce':
>> net/netfilter/nft_bitwise.c:306:28: warning: assignment discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers]
     306 |                 track->cur = expr;
         |                            ^
   net/netfilter/nft_bitwise.c: In function 'nft_bitwise_fast_reduce':
   net/netfilter/nft_bitwise.c:454:28: warning: assignment discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers]
     454 |                 track->cur = expr;
         |                            ^


vim +/const +306 net/netfilter/nft_bitwise.c

bd8699e9e29287 Pablo Neira Ayuso 2019-07-30  281  
be5650f8f47e8c Pablo Neira Ayuso 2022-01-09  282  static bool nft_bitwise_reduce(struct nft_regs_track *track,
be5650f8f47e8c Pablo Neira Ayuso 2022-01-09  283  			       const struct nft_expr *expr)
be5650f8f47e8c Pablo Neira Ayuso 2022-01-09  284  {
be5650f8f47e8c Pablo Neira Ayuso 2022-01-09  285  	const struct nft_bitwise *priv = nft_expr_priv(expr);
be5650f8f47e8c Pablo Neira Ayuso 2022-01-09  286  	const struct nft_bitwise *bitwise;
34cc9e52884a16 Pablo Neira Ayuso 2022-03-14  287  	unsigned int regcount;
34cc9e52884a16 Pablo Neira Ayuso 2022-03-14  288  	u8 dreg;
34cc9e52884a16 Pablo Neira Ayuso 2022-03-14  289  	int i;
be5650f8f47e8c Pablo Neira Ayuso 2022-01-09  290  
be5650f8f47e8c Pablo Neira Ayuso 2022-01-09  291  	if (!track->regs[priv->sreg].selector)
be5650f8f47e8c Pablo Neira Ayuso 2022-01-09  292  		return false;
be5650f8f47e8c Pablo Neira Ayuso 2022-01-09  293  
be5650f8f47e8c Pablo Neira Ayuso 2022-01-09  294  	bitwise = nft_expr_priv(expr);
be5650f8f47e8c Pablo Neira Ayuso 2022-01-09  295  	if (track->regs[priv->sreg].selector == track->regs[priv->dreg].selector &&
34cc9e52884a16 Pablo Neira Ayuso 2022-03-14  296  	    track->regs[priv->sreg].num_reg == 0 &&
be5650f8f47e8c Pablo Neira Ayuso 2022-01-09  297  	    track->regs[priv->dreg].bitwise &&
be5650f8f47e8c Pablo Neira Ayuso 2022-01-09  298  	    track->regs[priv->dreg].bitwise->ops == expr->ops &&
be5650f8f47e8c Pablo Neira Ayuso 2022-01-09  299  	    priv->sreg == bitwise->sreg &&
be5650f8f47e8c Pablo Neira Ayuso 2022-01-09  300  	    priv->dreg == bitwise->dreg &&
be5650f8f47e8c Pablo Neira Ayuso 2022-01-09  301  	    priv->op == bitwise->op &&
be5650f8f47e8c Pablo Neira Ayuso 2022-01-09  302  	    priv->len == bitwise->len &&
be5650f8f47e8c Pablo Neira Ayuso 2022-01-09  303  	    !memcmp(&priv->mask, &bitwise->mask, sizeof(priv->mask)) &&
be5650f8f47e8c Pablo Neira Ayuso 2022-01-09  304  	    !memcmp(&priv->xor, &bitwise->xor, sizeof(priv->xor)) &&
be5650f8f47e8c Pablo Neira Ayuso 2022-01-09  305  	    !memcmp(&priv->data, &bitwise->data, sizeof(priv->data))) {
be5650f8f47e8c Pablo Neira Ayuso 2022-01-09 @306  		track->cur = expr;
be5650f8f47e8c Pablo Neira Ayuso 2022-01-09  307  		return true;
be5650f8f47e8c Pablo Neira Ayuso 2022-01-09  308  	}
be5650f8f47e8c Pablo Neira Ayuso 2022-01-09  309  
34cc9e52884a16 Pablo Neira Ayuso 2022-03-14  310  	if (track->regs[priv->sreg].bitwise ||
34cc9e52884a16 Pablo Neira Ayuso 2022-03-14  311  	    track->regs[priv->sreg].num_reg != 0) {
34cc9e52884a16 Pablo Neira Ayuso 2022-03-14  312  		nft_reg_track_cancel(track, priv->dreg, priv->len);
be5650f8f47e8c Pablo Neira Ayuso 2022-01-09  313  		return false;
be5650f8f47e8c Pablo Neira Ayuso 2022-01-09  314  	}
be5650f8f47e8c Pablo Neira Ayuso 2022-01-09  315  
be5650f8f47e8c Pablo Neira Ayuso 2022-01-09  316  	if (priv->sreg != priv->dreg) {
34cc9e52884a16 Pablo Neira Ayuso 2022-03-14  317  		nft_reg_track_update(track, track->regs[priv->sreg].selector,
34cc9e52884a16 Pablo Neira Ayuso 2022-03-14  318  				     priv->dreg, priv->len);
be5650f8f47e8c Pablo Neira Ayuso 2022-01-09  319  	}
34cc9e52884a16 Pablo Neira Ayuso 2022-03-14  320  
34cc9e52884a16 Pablo Neira Ayuso 2022-03-14  321  	dreg = priv->dreg;
34cc9e52884a16 Pablo Neira Ayuso 2022-03-14  322  	regcount = DIV_ROUND_UP(priv->len, NFT_REG32_SIZE);
34cc9e52884a16 Pablo Neira Ayuso 2022-03-14  323  	for (i = 0; i < regcount; i++, dreg++)
be5650f8f47e8c Pablo Neira Ayuso 2022-01-09  324  		track->regs[priv->dreg].bitwise = expr;
be5650f8f47e8c Pablo Neira Ayuso 2022-01-09  325  
be5650f8f47e8c Pablo Neira Ayuso 2022-01-09  326  	return false;
be5650f8f47e8c Pablo Neira Ayuso 2022-01-09  327  }
be5650f8f47e8c Pablo Neira Ayuso 2022-01-09  328  

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