Re: [RFC PATCH bpf-next v2 3/9] cgroup: Add a new helper for cgroup1 hierarchy

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

Hi Yafang,

[This is a private test report for your RFC patch.]
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/Yafang-Shao/cgroup-Make-operations-on-the-cgroup-root_list-RCU-safe/20231017-204729
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
patch link:    https://lore.kernel.org/r/20231017124546.24608-4-laoar.shao%40gmail.com
patch subject: [RFC PATCH bpf-next v2 3/9] cgroup: Add a new helper for cgroup1 hierarchy
config: m68k-allyesconfig (https://download.01.org/0day-ci/archive/20231017/202310172347.Jp1j3Umf-lkp@intel.com/config)
compiler: m68k-linux-gcc (GCC) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231017/202310172347.Jp1j3Umf-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/202310172347.Jp1j3Umf-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> kernel/cgroup/cgroup-v1.c:1277: warning: expecting prototype for task_cgroup_id_within_hierarchy(). Prototype was for task_get_cgroup1_within_hierarchy() instead


vim +1277 kernel/cgroup/cgroup-v1.c

  1265	
  1266	/**
  1267	 * task_cgroup_id_within_hierarchy - Acquires the associated cgroup of a task
  1268	 * within a specific cgroup1 hierarchy. The cgroup1 hierarchy is identified by
  1269	 * its hierarchy ID.
  1270	 * @tsk: The target task
  1271	 * @hierarchy_id: The ID of a cgroup1 hierarchy
  1272	 *
  1273	 * On success, the cgroup is returned. On failure, ERR_PTR is returned.
  1274	 * We limit it to cgroup1 only.
  1275	 */
  1276	struct cgroup *task_get_cgroup1_within_hierarchy(struct task_struct *tsk, int hierarchy_id)
> 1277	{
  1278		struct cgroup *cgrp = ERR_PTR(-ENOENT);
  1279		struct cgroup_root *root;
  1280	
  1281		rcu_read_lock();
  1282		list_for_each_entry(root, &cgroup_roots, root_list) {
  1283			/* cgroup1 only*/
  1284			if (root == &cgrp_dfl_root)
  1285				continue;
  1286			if (root->hierarchy_id != hierarchy_id)
  1287				continue;
  1288			spin_lock_irq(&css_set_lock);
  1289			cgrp = task_cgroup_from_root(tsk, root);
  1290			if (!cgrp || !cgroup_tryget(cgrp))
  1291				cgrp = ERR_PTR(-ENOENT);
  1292			spin_unlock_irq(&css_set_lock);
  1293			break;
  1294		}
  1295		rcu_read_unlock();
  1296		return cgrp;
  1297	}
  1298	

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