#ifndef _LINUX_PID_NS_H
  #define _LINUX_PID_NS_H

  
  #include <linux/sched.h>

  #include <linux/bug.h>

  #include <linux/mm.h>

  #include <linux/workqueue.h>

  #include <linux/threads.h>

  #include <linux/nsproxy.h>
  #include <linux/kref.h>

  #include <linux/ns_common.h>

  
  struct pidmap {
         atomic_t nr_free;
         void *page;
  };

  #define BITS_PER_PAGE		(PAGE_SIZE * 8)
  #define BITS_PER_PAGE_MASK	(BITS_PER_PAGE-1)
  #define PIDMAP_ENTRIES		((PID_MAX_LIMIT+BITS_PER_PAGE-1)/BITS_PER_PAGE)

  struct fs_pin;

  struct pid_namespace {

  	struct kref kref;
  	struct pidmap pidmap[PIDMAP_ENTRIES];

  	struct rcu_head rcu;

  	int last_pid;

  	unsigned int nr_hashed;

  	struct task_struct *child_reaper;

  	struct kmem_cache *pid_cachep;

  	unsigned int level;

  	struct pid_namespace *parent;

  #ifdef CONFIG_PROC_FS
  	struct vfsmount *proc_mnt;

  	struct dentry *proc_self;

  	struct dentry *proc_thread_self;

  #endif

  #ifdef CONFIG_BSD_PROCESS_ACCT

  	struct fs_pin *bacct;

  #endif

  	struct user_namespace *user_ns;

  	struct ucounts *ucounts;

  	struct work_struct proc_work;

  	kgid_t pid_gid;

  	int hide_pid;

  	int reboot;	/* group exit code if this pidns was rebooted */

  	struct ns_common ns;

  };

  extern struct pid_namespace init_pid_ns;

  #define PIDNS_HASH_ADDING (1U << 31)

  #ifdef CONFIG_PID_NS

  static inline struct pid_namespace *get_pid_ns(struct pid_namespace *ns)

  {

  	if (ns != &init_pid_ns)
  		kref_get(&ns->kref);

  	return ns;

  }

  extern struct pid_namespace *copy_pid_ns(unsigned long flags,
  	struct user_namespace *user_ns, struct pid_namespace *ns);

  extern void zap_pid_ns_processes(struct pid_namespace *pid_ns);

  extern int reboot_pid_ns(struct pid_namespace *pid_ns, int cmd);

  extern void put_pid_ns(struct pid_namespace *ns);

  #else /* !CONFIG_PID_NS */
  #include <linux/err.h>
  
  static inline struct pid_namespace *get_pid_ns(struct pid_namespace *ns)
  {
  	return ns;
  }

  static inline struct pid_namespace *copy_pid_ns(unsigned long flags,
  	struct user_namespace *user_ns, struct pid_namespace *ns)

  {
  	if (flags & CLONE_NEWPID)
  		ns = ERR_PTR(-EINVAL);
  	return ns;
  }
  
  static inline void put_pid_ns(struct pid_namespace *ns)
  {
  }

  static inline void zap_pid_ns_processes(struct pid_namespace *ns)
  {
  	BUG();
  }

  
  static inline int reboot_pid_ns(struct pid_namespace *pid_ns, int cmd)
  {
  	return 0;
  }

  #endif /* CONFIG_PID_NS */

  extern struct pid_namespace *task_active_pid_ns(struct task_struct *tsk);

  void pidhash_init(void);
  void pidmap_init(void);

  #endif /* _LINUX_PID_NS_H */