Re: [PATCH bpf-next v4 2/8] bpf: Introduce css_task open-coded iterator kfuncs

[kernel test robot]

Hi Chuyi,

kernel test robot noticed the following build warnings:

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

url:    https://github.com/intel-lab-lkp/linux/commits/Chuyi-Zhou/cgroup-Prepare-for-using-css_task_iter_-in-BPF/20231007-204750
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
patch link:    https://lore.kernel.org/r/20231007124522.34834-3-zhouchuyi%40bytedance.com
patch subject: [PATCH bpf-next v4 2/8] bpf: Introduce css_task open-coded iterator kfuncs
config: m68k-allyesconfig (https://download.01.org/0day-ci/archive/20231007/202310072246.OfAldQpf-lkp@xxxxxxxxx/config)
compiler: m68k-linux-gcc (GCC) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231007/202310072246.OfAldQpf-lkp@xxxxxxxxx/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@xxxxxxxxx>
| Closes: https://lore.kernel.org/oe-kbuild-all/202310072246.OfAldQpf-lkp@xxxxxxxxx/

All warnings (new ones prefixed by >>):

>> kernel/bpf/task_iter.c:815:17: warning: no previous prototype for 'bpf_iter_css_task_new' [-Wmissing-prototypes]
     815 | __bpf_kfunc int bpf_iter_css_task_new(struct bpf_iter_css_task *it,
         |                 ^~~~~~~~~~~~~~~~~~~~~
>> kernel/bpf/task_iter.c:840:33: warning: no previous prototype for 'bpf_iter_css_task_next' [-Wmissing-prototypes]
     840 | __bpf_kfunc struct task_struct *bpf_iter_css_task_next(struct bpf_iter_css_task *it)
         |                                 ^~~~~~~~~~~~~~~~~~~~~~
>> kernel/bpf/task_iter.c:849:18: warning: no previous prototype for 'bpf_iter_css_task_destroy' [-Wmissing-prototypes]
     849 | __bpf_kfunc void bpf_iter_css_task_destroy(struct bpf_iter_css_task *it)
         |                  ^~~~~~~~~~~~~~~~~~~~~~~~~


vim +/bpf_iter_css_task_new +815 kernel/bpf/task_iter.c

   814	
 > 815	__bpf_kfunc int bpf_iter_css_task_new(struct bpf_iter_css_task *it,
   816			struct cgroup_subsys_state *css, unsigned int flags)
   817	{
   818		struct bpf_iter_css_task_kern *kit = (void *)it;
   819	
   820		BUILD_BUG_ON(sizeof(struct bpf_iter_css_task_kern) != sizeof(struct bpf_iter_css_task));
   821		BUILD_BUG_ON(__alignof__(struct bpf_iter_css_task_kern) !=
   822						__alignof__(struct bpf_iter_css_task));
   823		kit->css_it = NULL;
   824		switch (flags) {
   825		case CSS_TASK_ITER_PROCS | CSS_TASK_ITER_THREADED:
   826		case CSS_TASK_ITER_PROCS:
   827		case 0:
   828			break;
   829		default:
   830			return -EINVAL;
   831		}
   832	
   833		kit->css_it = bpf_mem_alloc(&bpf_global_ma, sizeof(struct css_task_iter));
   834		if (!kit->css_it)
   835			return -ENOMEM;
   836		css_task_iter_start(css, flags, kit->css_it);
   837		return 0;
   838	}
   839	
 > 840	__bpf_kfunc struct task_struct *bpf_iter_css_task_next(struct bpf_iter_css_task *it)
   841	{
   842		struct bpf_iter_css_task_kern *kit = (void *)it;
   843	
   844		if (!kit->css_it)
   845			return NULL;
   846		return css_task_iter_next(kit->css_it);
   847	}
   848	
 > 849	__bpf_kfunc void bpf_iter_css_task_destroy(struct bpf_iter_css_task *it)
   850	{
   851		struct bpf_iter_css_task_kern *kit = (void *)it;
   852	
   853		if (!kit->css_it)
   854			return;
   855		css_task_iter_end(kit->css_it);
   856		bpf_mem_free(&bpf_global_ma, kit->css_it);
   857	}
   858	

-- 
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https://github.com/intel/lkp-tests/wiki