[linux-next:master 10579/14992] kernel/bpf/task_iter.c:940:9: warning: return makes pointer from integer without a cast

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

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
head:   fe1998aa935b44ef873193c0772c43bce74f17dc
commit: 9c66dc94b62aef23300f05f63404afb8990920b4 [10579/14992] bpf: Introduce css_task open-coded iterator kfuncs
config: i386-buildonly-randconfig-006-20231026 (https://download.01.org/0day-ci/archive/20231026/202310260528.aHWgVFqq-lkp@intel.com/config)
compiler: gcc-7 (Ubuntu 7.5.0-6ubuntu2) 7.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231026/202310260528.aHWgVFqq-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/202310260528.aHWgVFqq-lkp@intel.com/

All warnings (new ones prefixed by >>):

   kernel/bpf/task_iter.c:831:17: warning: no previous declaration for 'bpf_iter_task_vma_new' [-Wmissing-declarations]
    __bpf_kfunc int bpf_iter_task_vma_new(struct bpf_iter_task_vma *it,
                    ^~~~~~~~~~~~~~~~~~~~~
   kernel/bpf/task_iter.c:875:36: warning: no previous declaration for 'bpf_iter_task_vma_next' [-Wmissing-declarations]
    __bpf_kfunc struct vm_area_struct *bpf_iter_task_vma_next(struct bpf_iter_task_vma *it)
                                       ^~~~~~~~~~~~~~~~~~~~~~
   kernel/bpf/task_iter.c:884:18: warning: no previous declaration for 'bpf_iter_task_vma_destroy' [-Wmissing-declarations]
    __bpf_kfunc void bpf_iter_task_vma_destroy(struct bpf_iter_task_vma *it)
                     ^~~~~~~~~~~~~~~~~~~~~~~~~
   kernel/bpf/task_iter.c:909:17: warning: no previous declaration for 'bpf_iter_css_task_new' [-Wmissing-declarations]
    __bpf_kfunc int bpf_iter_css_task_new(struct bpf_iter_css_task *it,
                    ^~~~~~~~~~~~~~~~~~~~~
   kernel/bpf/task_iter.c: In function 'bpf_iter_css_task_new':
   kernel/bpf/task_iter.c:919:7: error: 'CSS_TASK_ITER_PROCS' undeclared (first use in this function); did you mean 'BPF_TASK_ITER_TGID'?
     case CSS_TASK_ITER_PROCS | CSS_TASK_ITER_THREADED:
          ^~~~~~~~~~~~~~~~~~~
          BPF_TASK_ITER_TGID
   kernel/bpf/task_iter.c:919:7: note: each undeclared identifier is reported only once for each function it appears in
   kernel/bpf/task_iter.c:919:29: error: 'CSS_TASK_ITER_THREADED' undeclared (first use in this function); did you mean 'CSS_TASK_ITER_PROCS'?
     case CSS_TASK_ITER_PROCS | CSS_TASK_ITER_THREADED:
                                ^~~~~~~~~~~~~~~~~~~~~~
                                CSS_TASK_ITER_PROCS
   kernel/bpf/task_iter.c:927:53: error: invalid application of 'sizeof' to incomplete type 'struct css_task_iter'
     kit->css_it = bpf_mem_alloc(&bpf_global_ma, sizeof(struct css_task_iter));
                                                        ^~~~~~
   kernel/bpf/task_iter.c:930:2: error: implicit declaration of function 'css_task_iter_start'; did you mean '__sg_page_iter_start'? [-Werror=implicit-function-declaration]
     css_task_iter_start(css, flags, kit->css_it);
     ^~~~~~~~~~~~~~~~~~~
     __sg_page_iter_start
   kernel/bpf/task_iter.c: At top level:
   kernel/bpf/task_iter.c:934:33: warning: no previous declaration for 'bpf_iter_css_task_next' [-Wmissing-declarations]
    __bpf_kfunc struct task_struct *bpf_iter_css_task_next(struct bpf_iter_css_task *it)
                                    ^~~~~~~~~~~~~~~~~~~~~~
   kernel/bpf/task_iter.c: In function 'bpf_iter_css_task_next':
   kernel/bpf/task_iter.c:940:9: error: implicit declaration of function 'css_task_iter_next'; did you mean '__sg_page_iter_next'? [-Werror=implicit-function-declaration]
     return css_task_iter_next(kit->css_it);
            ^~~~~~~~~~~~~~~~~~
            __sg_page_iter_next
>> kernel/bpf/task_iter.c:940:9: warning: return makes pointer from integer without a cast [-Wint-conversion]
     return css_task_iter_next(kit->css_it);
            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   kernel/bpf/task_iter.c: At top level:
   kernel/bpf/task_iter.c:943:18: warning: no previous declaration for 'bpf_iter_css_task_destroy' [-Wmissing-declarations]
    __bpf_kfunc void bpf_iter_css_task_destroy(struct bpf_iter_css_task *it)
                     ^~~~~~~~~~~~~~~~~~~~~~~~~
   kernel/bpf/task_iter.c: In function 'bpf_iter_css_task_destroy':
   kernel/bpf/task_iter.c:949:2: error: implicit declaration of function 'css_task_iter_end'; did you mean 'vma_iter_end'? [-Werror=implicit-function-declaration]
     css_task_iter_end(kit->css_it);
     ^~~~~~~~~~~~~~~~~
     vma_iter_end
   cc1: some warnings being treated as errors


vim +940 kernel/bpf/task_iter.c

   933	
   934	__bpf_kfunc struct task_struct *bpf_iter_css_task_next(struct bpf_iter_css_task *it)
   935	{
   936		struct bpf_iter_css_task_kern *kit = (void *)it;
   937	
   938		if (!kit->css_it)
   939			return NULL;
 > 940		return css_task_iter_next(kit->css_it);
   941	}
   942	

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