Rename nsproxy.pid_ns to nsproxy.pid_ns_for_children

nsproxy.pid_ns is *not* the task's pid namespace.  The name should clarify
that.

This makes it more obvious that setns on a pid namespace is weird --
it won't change the pid namespace shown in procfs.

Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Reviewed-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/kernel/fork.c b/kernel/fork.c
index e23bb19..bf46287 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1177,7 +1177,8 @@
 	 * don't allow the creation of threads.
 	 */
 	if ((clone_flags & (CLONE_VM|CLONE_NEWPID)) &&
-	    (task_active_pid_ns(current) != current->nsproxy->pid_ns))
+	    (task_active_pid_ns(current) !=
+	     current->nsproxy->pid_ns_for_children))
 		return ERR_PTR(-EINVAL);
 
 	retval = security_task_create(clone_flags);
@@ -1351,7 +1352,7 @@
 
 	if (pid != &init_struct_pid) {
 		retval = -ENOMEM;
-		pid = alloc_pid(p->nsproxy->pid_ns);
+		pid = alloc_pid(p->nsproxy->pid_ns_for_children);
 		if (!pid)
 			goto bad_fork_cleanup_io;
 	}
diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index 364ceab..997cbb9 100644
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -29,15 +29,15 @@
 static struct kmem_cache *nsproxy_cachep;
 
 struct nsproxy init_nsproxy = {
-	.count	= ATOMIC_INIT(1),
-	.uts_ns	= &init_uts_ns,
+	.count			= ATOMIC_INIT(1),
+	.uts_ns			= &init_uts_ns,
 #if defined(CONFIG_POSIX_MQUEUE) || defined(CONFIG_SYSVIPC)
-	.ipc_ns	= &init_ipc_ns,
+	.ipc_ns			= &init_ipc_ns,
 #endif
-	.mnt_ns	= NULL,
-	.pid_ns	= &init_pid_ns,
+	.mnt_ns			= NULL,
+	.pid_ns_for_children	= &init_pid_ns,
 #ifdef CONFIG_NET
-	.net_ns	= &init_net,
+	.net_ns			= &init_net,
 #endif
 };
 
@@ -85,9 +85,10 @@
 		goto out_ipc;
 	}
 
-	new_nsp->pid_ns = copy_pid_ns(flags, user_ns, tsk->nsproxy->pid_ns);
-	if (IS_ERR(new_nsp->pid_ns)) {
-		err = PTR_ERR(new_nsp->pid_ns);
+	new_nsp->pid_ns_for_children =
+		copy_pid_ns(flags, user_ns, tsk->nsproxy->pid_ns_for_children);
+	if (IS_ERR(new_nsp->pid_ns_for_children)) {
+		err = PTR_ERR(new_nsp->pid_ns_for_children);
 		goto out_pid;
 	}
 
@@ -100,8 +101,8 @@
 	return new_nsp;
 
 out_net:
-	if (new_nsp->pid_ns)
-		put_pid_ns(new_nsp->pid_ns);
+	if (new_nsp->pid_ns_for_children)
+		put_pid_ns(new_nsp->pid_ns_for_children);
 out_pid:
 	if (new_nsp->ipc_ns)
 		put_ipc_ns(new_nsp->ipc_ns);
@@ -174,8 +175,8 @@
 		put_uts_ns(ns->uts_ns);
 	if (ns->ipc_ns)
 		put_ipc_ns(ns->ipc_ns);
-	if (ns->pid_ns)
-		put_pid_ns(ns->pid_ns);
+	if (ns->pid_ns_for_children)
+		put_pid_ns(ns->pid_ns_for_children);
 	put_net(ns->net_ns);
 	kmem_cache_free(nsproxy_cachep, ns);
 }
diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c
index 6917e8e..601bb36 100644
--- a/kernel/pid_namespace.c
+++ b/kernel/pid_namespace.c
@@ -349,8 +349,8 @@
 	if (ancestor != active)
 		return -EINVAL;
 
-	put_pid_ns(nsproxy->pid_ns);
-	nsproxy->pid_ns = get_pid_ns(new);
+	put_pid_ns(nsproxy->pid_ns_for_children);
+	nsproxy->pid_ns_for_children = get_pid_ns(new);
 	return 0;
 }