Re: [PATCH bpf 2/3] net: fix usage of multi-buffer BPF helper for ZC AF_XDP

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

Hi Maciej,

kernel test robot noticed the following build errors:

[auto build test ERROR on bpf/master]

url:    https://github.com/intel-lab-lkp/linux/commits/Maciej-Fijalkowski/xsk-recycle-buffer-in-case-Rx-queue-was-full/20231208-193306
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git master
patch link:    https://lore.kernel.org/r/20231208112945.313687-3-maciej.fijalkowski%40intel.com
patch subject: [PATCH bpf 2/3] net: fix usage of multi-buffer BPF helper for ZC AF_XDP
config: i386-buildonly-randconfig-003-20231208 (https://download.01.org/0day-ci/archive/20231209/202312090104.6EOsoGVa-lkp@intel.com/config)
compiler: clang version 16.0.4 (https://github.com/llvm/llvm-project.git ae42196bc493ffe877a7e3dff8be32035dea4d07)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231209/202312090104.6EOsoGVa-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@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202312090104.6EOsoGVa-lkp@intel.com/

All errors (new ones prefixed by >>):

>> net/core/filter.c:4102:3: error: call to undeclared function 'xsk_buff_get_tail'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
                   xsk_buff_get_tail(xdp)->data_end -= shrink;
                   ^
   net/core/filter.c:4102:3: note: did you mean 'xsk_buff_get_frag'?
   include/net/xdp_sock_drv.h:324:32: note: 'xsk_buff_get_frag' declared here
   static inline struct xdp_buff *xsk_buff_get_frag(struct xdp_buff *first)
                                  ^
>> net/core/filter.c:4102:27: error: member reference type 'int' is not a pointer
                   xsk_buff_get_tail(xdp)->data_end -= shrink;
                   ~~~~~~~~~~~~~~~~~~~~~~  ^
   net/core/filter.c:4115:14: error: call to undeclared function 'xsk_buff_get_tail'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
                           zc_frag = xsk_buff_get_tail(xdp);
                                     ^
>> net/core/filter.c:4115:12: error: incompatible integer to pointer conversion assigning to 'struct xdp_buff *' from 'int' [-Wint-conversion]
                           zc_frag = xsk_buff_get_tail(xdp);
                                   ^ ~~~~~~~~~~~~~~~~~~~~~~
>> net/core/filter.c:4117:4: error: call to undeclared function 'xsk_buff_tail_del'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
                           xsk_buff_tail_del(zc_frag);
                           ^
   5 errors generated.


vim +/xsk_buff_get_tail +4102 net/core/filter.c

  4097	
  4098	static void __shrink_data(struct xdp_buff *xdp, struct xdp_mem_info *mem_info,
  4099				  skb_frag_t *frag, int shrink)
  4100	{
  4101		if (mem_info->type == MEM_TYPE_XSK_BUFF_POOL)
> 4102			xsk_buff_get_tail(xdp)->data_end -= shrink;
  4103		skb_frag_size_sub(frag, shrink);
  4104	}
  4105	
  4106	static bool shrink_data(struct xdp_buff *xdp, skb_frag_t *frag, int shrink)
  4107	{
  4108		struct xdp_mem_info *mem_info = &xdp->rxq->mem;
  4109	
  4110		if (skb_frag_size(frag) == shrink) {
  4111			struct page *page = skb_frag_page(frag);
  4112			struct xdp_buff *zc_frag = NULL;
  4113	
  4114			if (mem_info->type == MEM_TYPE_XSK_BUFF_POOL) {
> 4115				zc_frag = xsk_buff_get_tail(xdp);
  4116				xdp_buff_clear_frags_flag(zc_frag);
> 4117				xsk_buff_tail_del(zc_frag);
  4118			}
  4119	
  4120			__xdp_return(page_address(page), mem_info, false, zc_frag);
  4121			return true;
  4122		}
  4123		__shrink_data(xdp, mem_info, frag, shrink);
  4124		return false;
  4125	}
  4126	

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