[PATCH] namespaces: fix exit race by splitting exit

[sfrench/cifs-2.6.git] / include / linux / nsproxy.h

diff --git a/include/linux/nsproxy.h b/include/linux/nsproxy.h
index 0b9f0dc30d6114a1f5177a7fde829d2199137172..678e1d38effba0866464ec560639fe07aaa929fa 100644 (file)
--- a/include/linux/nsproxy.h
+++ b/include/linux/nsproxy.h
@@ -35,22 +35,30 @@ struct nsproxy *dup_namespaces(struct nsproxy *orig);
 int copy_namespaces(int flags, struct task_struct *tsk);
 void get_task_namespaces(struct task_struct *tsk);
 void free_nsproxy(struct nsproxy *ns);
+struct nsproxy *put_nsproxy(struct nsproxy *ns);
 
-static inline void put_nsproxy(struct nsproxy *ns)
+static inline void finalize_put_nsproxy(struct nsproxy *ns)
 {
-       if (atomic_dec_and_test(&ns->count)) {
+       if (ns)
                free_nsproxy(ns);
-       }
 }
 
-static inline void exit_task_namespaces(struct task_struct *p)
+static inline void put_and_finalize_nsproxy(struct nsproxy *ns)
 {
-       struct nsproxy *ns = p->nsproxy;
-       if (ns) {
-               task_lock(p);
-               p->nsproxy = NULL;
-               task_unlock(p);
-               put_nsproxy(ns);
-       }
+       finalize_put_nsproxy(put_nsproxy(ns));
+}
+
+static inline struct nsproxy *preexit_task_namespaces(struct task_struct *p)
+{
+       return put_nsproxy(p->nsproxy);
+}
+
+static inline void exit_task_namespaces(struct task_struct *p,
+                                               struct nsproxy *ns)
+{
+       task_lock(p);
+       p->nsproxy = NULL;
+       task_unlock(p);
+       finalize_put_nsproxy(ns);
 }
 #endif