proc_visitor      590 include/linux/sched/signal.h typedef int (*proc_visitor)(struct task_struct *p, void *data);
proc_visitor      591 include/linux/sched/signal.h void walk_process_tree(struct task_struct *top, proc_visitor, void *);
proc_visitor     2647 kernel/fork.c  void walk_process_tree(struct task_struct *top, proc_visitor visitor, void *data)