+#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 pid_namespace *ns)
+{
+ if (flags & CLONE_NEWPID)
+ ns = ERR_PTR(-EINVAL);
+ return ns;
+}
+
+static inline void put_pid_ns(struct pid_namespace *ns)
+{
+}
+
+#endif /* CONFIG_PID_NS */
+
+static inline struct pid_namespace *task_active_pid_ns(struct task_struct *tsk)
+{
+ return tsk->nsproxy->pid_ns;
+}
+
+static inline struct task_struct *task_child_reaper(struct task_struct *tsk)