Re: [PATCH bpf-next v2 4/8] bpf: Introduce cgroup iter

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

Hi Yosry,

Thank you for the patch! Yet something to improve:

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

url:    https://github.com/intel-lab-lkp/linux/commits/Yosry-Ahmed/bpf-rstat-cgroup-hierarchical-stats/20220611-034720
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
config: m68k-defconfig (https://download.01.org/0day-ci/archive/20220611/202206111529.2okIVRo9-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/619857fd1ec4f351376ffcaaec20acc9aae9486f
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Yosry-Ahmed/bpf-rstat-cgroup-hierarchical-stats/20220611-034720
        git checkout 619857fd1ec4f351376ffcaaec20acc9aae9486f
        # 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

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

All errors (new ones prefixed by >>):

   In file included from kernel/bpf/cgroup_iter.c:9:
>> kernel/bpf/../cgroup/cgroup-internal.h:78:41: error: field 'iter' has incomplete type
      78 |                 struct css_task_iter    iter;
         |                                         ^~~~
   kernel/bpf/../cgroup/cgroup-internal.h: In function 'cgroup_is_dead':
   kernel/bpf/../cgroup/cgroup-internal.h:188:22: error: invalid use of undefined type 'const struct cgroup'
     188 |         return !(cgrp->self.flags & CSS_ONLINE);
         |                      ^~
   kernel/bpf/../cgroup/cgroup-internal.h:188:37: error: 'CSS_ONLINE' undeclared (first use in this function); did you mean 'N_ONLINE'?
     188 |         return !(cgrp->self.flags & CSS_ONLINE);
         |                                     ^~~~~~~~~~
         |                                     N_ONLINE
   kernel/bpf/../cgroup/cgroup-internal.h:188:37: note: each undeclared identifier is reported only once for each function it appears in
   kernel/bpf/../cgroup/cgroup-internal.h: In function 'notify_on_release':
   kernel/bpf/../cgroup/cgroup-internal.h:193:25: error: 'CGRP_NOTIFY_ON_RELEASE' undeclared (first use in this function)
     193 |         return test_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags);
         |                         ^~~~~~~~~~~~~~~~~~~~~~
   kernel/bpf/../cgroup/cgroup-internal.h:193:54: error: invalid use of undefined type 'const struct cgroup'
     193 |         return test_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags);
         |                                                      ^~
   kernel/bpf/../cgroup/cgroup-internal.h: In function 'put_css_set':
   kernel/bpf/../cgroup/cgroup-internal.h:207:39: error: invalid use of undefined type 'struct css_set'
     207 |         if (refcount_dec_not_one(&cset->refcount))
         |                                       ^~
   kernel/bpf/../cgroup/cgroup-internal.h: In function 'get_css_set':
   kernel/bpf/../cgroup/cgroup-internal.h:220:27: error: invalid use of undefined type 'struct css_set'
     220 |         refcount_inc(&cset->refcount);
         |                           ^~
   kernel/bpf/../cgroup/cgroup-internal.h: At top level:
   kernel/bpf/../cgroup/cgroup-internal.h:284:22: error: array type has incomplete element type 'struct cftype'
     284 | extern struct cftype cgroup1_base_files[];
         |                      ^~~~~~~~~~~~~~~~~~
   kernel/bpf/cgroup_iter.c: In function 'cgroup_iter_seq_start':
>> kernel/bpf/cgroup_iter.c:55:24: error: implicit declaration of function 'css_next_descendant_pre' [-Werror=implicit-function-declaration]
      55 |                 return css_next_descendant_pre(NULL, p->start_css);
         |                        ^~~~~~~~~~~~~~~~~~~~~~~
   kernel/bpf/cgroup_iter.c:55:24: warning: returning 'int' from a function with return type 'void *' makes pointer from integer without a cast [-Wint-conversion]
      55 |                 return css_next_descendant_pre(NULL, p->start_css);
         |                        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> kernel/bpf/cgroup_iter.c:57:24: error: implicit declaration of function 'css_next_descendant_post' [-Werror=implicit-function-declaration]
      57 |                 return css_next_descendant_post(NULL, p->start_css);
         |                        ^~~~~~~~~~~~~~~~~~~~~~~~
   kernel/bpf/cgroup_iter.c:57:24: warning: returning 'int' from a function with return type 'void *' makes pointer from integer without a cast [-Wint-conversion]
      57 |                 return css_next_descendant_post(NULL, p->start_css);
         |                        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   kernel/bpf/cgroup_iter.c: In function 'cgroup_iter_seq_next':
   kernel/bpf/cgroup_iter.c:83:24: warning: returning 'int' from a function with return type 'void *' makes pointer from integer without a cast [-Wint-conversion]
      83 |                 return css_next_descendant_pre(curr, p->start_css);
         |                        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   kernel/bpf/cgroup_iter.c:85:24: warning: returning 'int' from a function with return type 'void *' makes pointer from integer without a cast [-Wint-conversion]
      85 |                 return css_next_descendant_post(curr, p->start_css);
         |                        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> kernel/bpf/cgroup_iter.c:87:28: error: invalid use of undefined type 'struct cgroup_subsys_state'
      87 |                 return curr->parent;
         |                            ^~
   kernel/bpf/cgroup_iter.c: In function '__cgroup_iter_seq_show':
   kernel/bpf/cgroup_iter.c:100:38: error: invalid use of undefined type 'struct cgroup_subsys_state'
     100 |         if (css && cgroup_is_dead(css->cgroup))
         |                                      ^~
   kernel/bpf/cgroup_iter.c:104:31: error: invalid use of undefined type 'struct cgroup_subsys_state'
     104 |         ctx.cgroup = css ? css->cgroup : NULL;
         |                               ^~
   kernel/bpf/cgroup_iter.c: In function 'cgroup_iter_seq_init':
>> kernel/bpf/cgroup_iter.c:137:29: error: invalid use of undefined type 'struct cgroup'
     137 |         p->start_css = &cgrp->self;
         |                             ^~
   kernel/bpf/cgroup_iter.c: In function 'bpf_iter_attach_cgroup':
>> kernel/bpf/cgroup_iter.c:157:24: error: implicit declaration of function 'cgroup_get_from_fd'; did you mean 'cgroup_get_from_id'? [-Werror=implicit-function-declaration]
     157 |                 cgrp = cgroup_get_from_fd(fd);
         |                        ^~~~~~~~~~~~~~~~~~
         |                        cgroup_get_from_id
   kernel/bpf/cgroup_iter.c:157:22: warning: assignment to 'struct cgroup *' from 'int' makes pointer from integer without a cast [-Wint-conversion]
     157 |                 cgrp = cgroup_get_from_fd(fd);
         |                      ^
>> kernel/bpf/cgroup_iter.c:159:24: error: implicit declaration of function 'cgroup_get_from_path'; did you mean 'cgroup_get_from_id'? [-Werror=implicit-function-declaration]
     159 |                 cgrp = cgroup_get_from_path("/");
         |                        ^~~~~~~~~~~~~~~~~~~~
         |                        cgroup_get_from_id
   kernel/bpf/cgroup_iter.c:159:22: warning: assignment to 'struct cgroup *' from 'int' makes pointer from integer without a cast [-Wint-conversion]
     159 |                 cgrp = cgroup_get_from_path("/");
         |                      ^
   kernel/bpf/cgroup_iter.c: In function 'bpf_iter_cgroup_show_fdinfo':
>> kernel/bpf/cgroup_iter.c:190:9: error: implicit declaration of function 'cgroup_path_ns'; did you mean 'cgroup_parent'? [-Werror=implicit-function-declaration]
     190 |         cgroup_path_ns(aux->cgroup.start, buf, PATH_MAX,
         |         ^~~~~~~~~~~~~~
         |         cgroup_parent
   kernel/bpf/cgroup_iter.c: In function 'cgroup_iter_seq_next':
   kernel/bpf/cgroup_iter.c:88:1: error: control reaches end of non-void function [-Werror=return-type]
      88 | }
         | ^
   cc1: some warnings being treated as errors


vim +/iter +78 kernel/bpf/../cgroup/cgroup-internal.h

0d2b5955b36250 Tejun Heo 2022-01-06  68  
0d2b5955b36250 Tejun Heo 2022-01-06  69  struct cgroup_file_ctx {
e57457641613fe Tejun Heo 2022-01-06  70  	struct cgroup_namespace	*ns;
e57457641613fe Tejun Heo 2022-01-06  71  
0d2b5955b36250 Tejun Heo 2022-01-06  72  	struct {
0d2b5955b36250 Tejun Heo 2022-01-06  73  		void			*trigger;
0d2b5955b36250 Tejun Heo 2022-01-06  74  	} psi;
0d2b5955b36250 Tejun Heo 2022-01-06  75  
0d2b5955b36250 Tejun Heo 2022-01-06  76  	struct {
0d2b5955b36250 Tejun Heo 2022-01-06  77  		bool			started;
0d2b5955b36250 Tejun Heo 2022-01-06 @78  		struct css_task_iter	iter;
0d2b5955b36250 Tejun Heo 2022-01-06  79  	} procs;
0d2b5955b36250 Tejun Heo 2022-01-06  80  
0d2b5955b36250 Tejun Heo 2022-01-06  81  	struct {
0d2b5955b36250 Tejun Heo 2022-01-06  82  		struct cgroup_pidlist	*pidlist;
0d2b5955b36250 Tejun Heo 2022-01-06  83  	} procs1;
0d2b5955b36250 Tejun Heo 2022-01-06  84  };
0d2b5955b36250 Tejun Heo 2022-01-06  85  

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