From e6ef390a006766c5114b28d27b3eebc6b7c1aa4c Mon Sep 17 00:00:00 2001
From: "Eric W. Biederman" <ebiederm@xmission.com>
Date: Wed, 14 Nov 2007 17:00:13 -0800
Subject: [PATCH] --- yaml --- r: 73726 b: refs/heads/master c:
 57d5f66b86079efac5c9a7843cce2a9bcbe58fb8 h: refs/heads/master v: v3

---
 [refs]                              |  2 +-
 trunk/include/linux/pid_namespace.h | 23 +++++++++++++++++++++++
 trunk/init/Kconfig                  | 12 ++++++++++++
 trunk/kernel/pid.c                  |  2 ++
 4 files changed, 38 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index efb39a881a85..c08fa62b4bf7 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 42614fcde7bfdcbe43a7b17035c167dfebc354dd
+refs/heads/master: 57d5f66b86079efac5c9a7843cce2a9bcbe58fb8
diff --git a/trunk/include/linux/pid_namespace.h b/trunk/include/linux/pid_namespace.h
index 0135c76c76c6..1689e28483e4 100644
--- a/trunk/include/linux/pid_namespace.h
+++ b/trunk/include/linux/pid_namespace.h
@@ -29,6 +29,7 @@ struct pid_namespace {
 
 extern struct pid_namespace init_pid_ns;
 
+#ifdef CONFIG_PID_NS
 static inline struct pid_namespace *get_pid_ns(struct pid_namespace *ns)
 {
 	if (ns != &init_pid_ns)
@@ -45,6 +46,28 @@ static inline void put_pid_ns(struct pid_namespace *ns)
 		kref_put(&ns->kref, free_pid_ns);
 }
 
+#else /* !CONFIG_PID_NS */
+#include <linux/err.h>
+
+static inline struct pid_namespace *get_pid_ns(struct pid_namespace *ns)
+{
+	return ns;
+}
+
+static inline struct pid_namespace *
+copy_pid_ns(unsigned long flags, struct pid_namespace *ns)
+{
+	if (flags & CLONE_NEWPID)
+		ns = ERR_PTR(-EINVAL);
+	return ns;
+}
+
+static inline void put_pid_ns(struct pid_namespace *ns)
+{
+}
+
+#endif /* CONFIG_PID_NS */
+
 static inline struct pid_namespace *task_active_pid_ns(struct task_struct *tsk)
 {
 	return tsk->nsproxy->pid_ns;
diff --git a/trunk/init/Kconfig b/trunk/init/Kconfig
index 5b92e3aa1366..c5b354b1409e 100644
--- a/trunk/init/Kconfig
+++ b/trunk/init/Kconfig
@@ -215,6 +215,18 @@ config USER_NS
 	  vservers, to use user namespaces to provide different
 	  user info for different servers.  If unsure, say N.
 
+config PID_NS
+	bool "PID Namespaces (EXPERIMENTAL)"
+	default n
+	depends on EXPERIMENTAL
+	help
+	  Suport process id namespaces.  This allows having multiple
+	  process with the same pid as long as they are in different
+	  pid namespaces.  This is a building block of containers.
+
+	  Unless you want to work with an experimental feature
+	  say N here.
+
 config AUDIT
 	bool "Auditing support"
 	depends on NET
diff --git a/trunk/kernel/pid.c b/trunk/kernel/pid.c
index d1db36b94674..f815455431bf 100644
--- a/trunk/kernel/pid.c
+++ b/trunk/kernel/pid.c
@@ -537,6 +537,7 @@ static struct kmem_cache *create_pid_cachep(int nr_ids)
 	return NULL;
 }
 
+#ifdef CONFIG_PID_NS
 static struct pid_namespace *create_pid_namespace(int level)
 {
 	struct pid_namespace *ns;
@@ -621,6 +622,7 @@ void free_pid_ns(struct kref *kref)
 	if (parent != NULL)
 		put_pid_ns(parent);
 }
+#endif /* CONFIG_PID_NS */
 
 void zap_pid_ns_processes(struct pid_namespace *pid_ns)
 {