1 files changed, 18 insertions, 2 deletions

diff --git a/include/linux/pid_namespace.h b/include/linux/pid_namespace.h
index 54d79095e295..76e7c6b2cf33 100644
--- a/include/linux/pid_namespace.h
+++ b/include/linux/pid_namespace.h
@@ -5,6 +5,8 @@
 #include <linux/mm.h>
 #include <linux/threads.h>
 #include <linux/pid.h>
+#include <linux/nsproxy.h>
+#include <linux/kref.h>
 
 struct pidmap {
        atomic_t nr_free;
@@ -14,10 +16,24 @@ struct pidmap {
 #define PIDMAP_ENTRIES         ((PID_MAX_LIMIT + 8*PAGE_SIZE - 1)/PAGE_SIZE/8)
 
 struct pid_namespace {
-       struct pidmap pidmap[PIDMAP_ENTRIES];
-       int last_pid;
+        struct kref kref;
+        struct pidmap pidmap[PIDMAP_ENTRIES];
+        int last_pid;
 };
 
 extern struct pid_namespace init_pid_ns;
 
+static inline void get_pid_ns(struct pid_namespace *ns)
+{
+        kref_get(&ns->kref);
+}
+
+extern int copy_pid_ns(int flags, struct task_struct *tsk);
+extern void free_pid_ns(struct kref *kref);
+
+static inline void put_pid_ns(struct pid_namespace *ns)
+{
+        kref_put(&ns->kref, free_pid_ns);
+}
+
 #endif /* _LINUX_PID_NS_H */