Revert "[PATCH] namespaces: fix exit race by splitting exit"

This reverts commit 7a238fcba0629b6f2edbcd37458bae56fcf36be5 in
preparation for a better and simpler fix proposed by Eric Biederman
(and fixed up by Serge Hallyn)

Acked-by: Serge E. Hallyn <serue@us.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 11 insertions, 19 deletions

diff --git a/include/linux/nsproxy.h b/include/linux/nsproxy.h
index 678e1d38effb..0b9f0dc30d61 100644
--- a/include/linux/nsproxy.h
+++ b/include/linux/nsproxy.h
@@ -35,30 +35,22 @@ 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 finalize_put_nsproxy(struct nsproxy *ns)
+static inline void put_nsproxy(struct nsproxy *ns)
 {
-        if (ns)
+        if (atomic_dec_and_test(&ns->count)) {
                 free_nsproxy(ns);
+        }
 }
 
-static inline void put_and_finalize_nsproxy(struct nsproxy *ns)
+static inline void exit_task_namespaces(struct task_struct *p)
 {
-        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);
+        struct nsproxy *ns = p->nsproxy;
+        if (ns) {
+                task_lock(p);
+                p->nsproxy = NULL;
+                task_unlock(p);
+                put_nsproxy(ns);
+        }
 }
 #endif