Re: [PATCH bpf-next v1 12/15] net/netfilter: Add bpf_ct_kptr_get helper

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

Hi Kumar,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on next-20220217]
[cannot apply to bpf-next/master bpf/master linus/master v5.17-rc4 v5.17-rc3 v5.17-rc2 v5.17-rc5]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Kumar-Kartikeya-Dwivedi/Introduce-typed-pointer-support-in-BPF-maps/20220220-215105
base:    3c30cf91b5ecc7272b3d2942ae0505dd8320b81c
config: s390-defconfig (https://download.01.org/0day-ci/archive/20220221/202202211228.CO4wFX0Q-lkp@intel.com/config)
compiler: s390-linux-gcc (GCC) 11.2.0
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/0day-ci/linux/commit/79e35d4e4ee33a7692f0612065012307a361cd56
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Kumar-Kartikeya-Dwivedi/Introduce-typed-pointer-support-in-BPF-maps/20220220-215105
        git checkout 79e35d4e4ee33a7692f0612065012307a361cd56
        # save the config file to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=s390 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/nf_conntrack_bpf.c: In function 'bpf_ct_kptr_get':
>> net/netfilter/nf_conntrack_bpf.c:226:21: warning: variable 'net' set but not used [-Wunused-but-set-variable]
     226 |         struct net *net;
         |                     ^~~
   net/netfilter/nf_conntrack_bpf.c: At top level:
   net/netfilter/nf_conntrack_bpf.c:314:5: warning: no previous prototype for 'register_nf_conntrack_bpf' [-Wmissing-prototypes]
     314 | int register_nf_conntrack_bpf(void)
         |     ^~~~~~~~~~~~~~~~~~~~~~~~~


vim +/net +226 net/netfilter/nf_conntrack_bpf.c

   219	
   220	/* TODO: Just a PoC, need to reuse code in __nf_conntrack_find_get for this */
   221	struct nf_conn *bpf_ct_kptr_get(struct nf_conn **ptr, struct bpf_sock_tuple *bpf_tuple,
   222					u32 tuple__sz, u8 protonum, u8 direction)
   223	{
   224		struct nf_conntrack_tuple tuple;
   225		struct nf_conn *nfct;
 > 226		struct net *net;
   227		u64 *nfct_p;
   228		int ret;
   229	
   230		WARN_ON_ONCE(!rcu_read_lock_held());
   231	
   232		if ((protonum != IPPROTO_TCP && protonum != IPPROTO_UDP) ||
   233		    (direction != IP_CT_DIR_ORIGINAL && direction != IP_CT_DIR_REPLY))
   234			return NULL;
   235	
   236		/* ptr is actually pointer to u64 having address, hence recast u64 load
   237		 * to native pointer width.
   238		 */
   239		nfct_p = (u64 *)ptr;
   240		nfct = (struct nf_conn *)READ_ONCE(*nfct_p);
   241		if (!nfct || unlikely(!refcount_inc_not_zero(&nfct->ct_general.use)))
   242			return NULL;
   243	
   244		memset(&tuple, 0, sizeof(tuple));
   245		ret = bpf_fill_nf_tuple(&tuple, bpf_tuple, tuple__sz);
   246		if (ret < 0)
   247			goto end;
   248		tuple.dst.protonum = protonum;
   249	
   250		/* XXX: Need to allow passing in struct net *, or take netns_id, this is non-sense */
   251		net = nf_ct_net(nfct);
   252		if (!nf_ct_key_equal(&nfct->tuplehash[direction], &tuple,
   253				     &nf_ct_zone_dflt, nf_ct_net(nfct)))
   254			goto end;
   255		return nfct;
   256	end:
   257		nf_ct_put(nfct);
   258		return NULL;
   259	}
   260	

---
0-DAY CI Kernel Test Service, Intel Corporation
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