nsproxy: extract create_nsproxy()

clone_nsproxy() does useless copying of old nsproxy -- every pointer will
be rewritten to new ns or to old ns.  Remove copying, rename
clone_nsproxy(), create_nsproxy() will be used by C/R code to create fresh
nsproxy on restart.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel/nsproxy.c

@@ -26,19 +26,14 @@ static struct kmem_cache *nsproxy_cachep;
 
 struct nsproxy init_nsproxy = INIT_NSPROXY(init_nsproxy);
 
-/*
- * creates a copy of "orig" with refcount 1.
- */
-static inline struct nsproxy *clone_nsproxy(struct nsproxy *orig)
+static inline struct nsproxy *create_nsproxy(void)
 {
-	struct nsproxy *ns;
+	struct nsproxy *nsproxy;
 
-	ns = kmem_cache_alloc(nsproxy_cachep, GFP_KERNEL);
-	if (ns) {
-		memcpy(ns, orig, sizeof(struct nsproxy));
-		atomic_set(&ns->count, 1);
-	}
-	return ns;
+	nsproxy = kmem_cache_alloc(nsproxy_cachep, GFP_KERNEL);
+	if (nsproxy)
+		atomic_set(&nsproxy->count, 1);
+	return nsproxy;
 }
 
 /*
@@ -52,7 +47,7 @@ static struct nsproxy *create_new_namespaces(unsigned long flags,
 	struct nsproxy *new_nsp;
 	int err;
 
-	new_nsp = clone_nsproxy(tsk->nsproxy);
+	new_nsp = create_nsproxy();
 	if (!new_nsp)
 		return ERR_PTR(-ENOMEM);