1 files changed, 82 insertions, 6 deletions

diff --git a/kernel/pid.c b/kernel/pid.c
index 4b17acdb862f..f76097c60475 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -18,6 +18,12 @@
  * allocation scenario when all but one out of 1 million PIDs possible are
  * allocated already: the scanning of 32 list entries and at most PAGE_SIZE
  * bytes. The typical fastpath is a single successful setbit. Freeing is O(1).
+ *
+ * Pid namespaces:
+ *    (C) 2007 Pavel Emelyanov <xemul@openvz.org>, OpenVZ, SWsoft Inc.
+ *    (C) 2007 Sukadev Bhattiprolu <sukadev@us.ibm.com>, IBM
+ *     Many thanks to Oleg Nesterov for comments and help
+ *
  */
 
 #include <linux/mm.h>
@@ -456,8 +462,8 @@ static struct kmem_cache *create_pid_cachep(int nr_ids)
 
         snprintf(pcache->name, sizeof(pcache->name), "pid_%d", nr_ids);
         cachep = kmem_cache_create(pcache->name,
-                        /* FIXME add numerical ids here */
-                        sizeof(struct pid), 0, SLAB_HWCACHE_ALIGN, NULL);
+                        sizeof(struct pid) + (nr_ids - 1) * sizeof(struct upid),
+                        0, SLAB_HWCACHE_ALIGN, NULL);
         if (cachep == NULL)
                 goto err_cachep;
 
@@ -475,19 +481,89 @@ err_alloc:
         return NULL;
 }
 
+static struct pid_namespace *create_pid_namespace(int level)
+{
+        struct pid_namespace *ns;
+        int i;
+
+        ns = kmalloc(sizeof(struct pid_namespace), GFP_KERNEL);
+        if (ns == NULL)
+                goto out;
+
+        ns->pidmap[0].page = kzalloc(PAGE_SIZE, GFP_KERNEL);
+        if (!ns->pidmap[0].page)
+                goto out_free;
+
+        ns->pid_cachep = create_pid_cachep(level + 1);
+        if (ns->pid_cachep == NULL)
+                goto out_free_map;
+
+        kref_init(&ns->kref);
+        ns->last_pid = 0;
+        ns->child_reaper = NULL;
+        ns->level = level;
+
+        set_bit(0, ns->pidmap[0].page);
+        atomic_set(&ns->pidmap[0].nr_free, BITS_PER_PAGE - 1);
+
+        for (i = 1; i < PIDMAP_ENTRIES; i++) {
+                ns->pidmap[i].page = 0;
+                atomic_set(&ns->pidmap[i].nr_free, BITS_PER_PAGE);
+        }
+
+        return ns;
+
+out_free_map:
+        kfree(ns->pidmap[0].page);
+out_free:
+        kfree(ns);
+out:
+        return ERR_PTR(-ENOMEM);
+}
+
+static void destroy_pid_namespace(struct pid_namespace *ns)
+{
+        int i;
+
+        for (i = 0; i < PIDMAP_ENTRIES; i++)
+                kfree(ns->pidmap[i].page);
+        kfree(ns);
+}
+
 struct pid_namespace *copy_pid_ns(unsigned long flags, struct pid_namespace *old_ns)
 {
+        struct pid_namespace *new_ns;
+
         BUG_ON(!old_ns);
-        get_pid_ns(old_ns);
-        return old_ns;
+        new_ns = get_pid_ns(old_ns);
+        if (!(flags & CLONE_NEWPID))
+                goto out;
+
+        new_ns = ERR_PTR(-EINVAL);
+        if (flags & CLONE_THREAD)
+                goto out_put;
+
+        new_ns = create_pid_namespace(old_ns->level + 1);
+        if (!IS_ERR(new_ns))
+                new_ns->parent = get_pid_ns(old_ns);
+
+out_put:
+        put_pid_ns(old_ns);
+out:
+        return new_ns;
 }
 
 void free_pid_ns(struct kref *kref)
 {
-        struct pid_namespace *ns;
+        struct pid_namespace *ns, *parent;
 
         ns = container_of(kref, struct pid_namespace, kref);
-        kfree(ns);
+
+        parent = ns->parent;
+        destroy_pid_namespace(ns);
+
+        if (parent != NULL)
+                put_pid_ns(parent);
 }
 
 /*