3 files changed, 9 insertions, 3 deletions

diff --git a/include/linux/pid.h b/include/linux/pid.h
index 2c0007d17218..4dec047b1837 100644
--- a/include/linux/pid.h
+++ b/include/linux/pid.h
@@ -35,8 +35,9 @@ enum pid_type
  *
  * Holding a reference to struct pid solves both of these problems.
  * It is small so holding a reference does not consume a lot of
- * resources, and since a new struct pid is allocated when the numeric
- * pid value is reused we don't mistakenly refer to new processes.
+ * resources, and since a new struct pid is allocated when the numeric pid
+ * value is reused (when pids wrap around) we don't mistakenly refer to new
+ * processes.
  */
 
 struct pid
diff --git a/include/linux/pid_namespace.h b/include/linux/pid_namespace.h
index 76e7c6b2cf33..d2a9d419f01f 100644
--- a/include/linux/pid_namespace.h
+++ b/include/linux/pid_namespace.h
@@ -19,6 +19,7 @@ struct pid_namespace {
         struct kref kref;
         struct pidmap pidmap[PIDMAP_ENTRIES];
         int last_pid;
+        struct task_struct *child_reaper;
 };
 
 extern struct pid_namespace init_pid_ns;
@@ -36,4 +37,9 @@ static inline void put_pid_ns(struct pid_namespace *ns)
         kref_put(&ns->kref, free_pid_ns);
 }
 
+static inline struct task_struct *child_reaper(struct task_struct *tsk)
+{
+        return tsk->nsproxy->pid_ns->child_reaper;
+}
+
 #endif /* _LINUX_PID_NS_H */
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 6fec1d419714..f0317edea141 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1400,7 +1400,6 @@ extern NORET_TYPE void do_group_exit(int);
 extern void daemonize(const char *, ...);
 extern int allow_signal(int);
 extern int disallow_signal(int);
-extern struct task_struct *child_reaper;
 
 extern int do_execve(char *, char __user * __user *, char __user * __user *, struct pt_regs *);
 extern long do_fork(unsigned long, unsigned long, struct pt_regs *, unsigned long, int __user *, int __user *);