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>

4 files changed, 24 insertions, 18 deletions

diff --git a/include/linux/nsproxy.h b/include/linux/nsproxy.h
index 10e5947491c7..b4ec59d159ac 100644
--- a/include/linux/nsproxy.h
+++ b/include/linux/nsproxy.h
@@ -14,6 +14,10 @@ struct fs_struct;
  * A structure to contain pointers to all per-process
  * namespaces - fs (mount), uts, network, sysvipc, etc.
  *
+ * The pid namespace is an exception -- it's accessed using
+ * task_active_pid_ns.  The pid namespace here is the
+ * namespace that children will use.
+ *
  * 'count' is the number of tasks holding a reference.
  * The count for each namespace, then, will be the number
  * of nsproxies pointing to it, not the number of tasks.
@@ -27,7 +31,7 @@ struct nsproxy {
         struct uts_namespace *uts_ns;
         struct ipc_namespace *ipc_ns;
         struct mnt_namespace *mnt_ns;
-        struct pid_namespace *pid_ns;
+        struct pid_namespace *pid_ns_for_children;
         struct net           *net_ns;
 };
 extern struct nsproxy init_nsproxy;
diff --git a/kernel/fork.c b/kernel/fork.c
index e23bb19e2a3e..bf46287c91a4 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1177,7 +1177,8 @@ static struct task_struct *copy_process(unsigned long clone_flags,
          * 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 @@ static struct task_struct *copy_process(unsigned long clone_flags,
 
         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 364ceab15f0c..997cbb951a3b 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 @@ static struct nsproxy *create_new_namespaces(unsigned long flags,
                 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 @@ static struct nsproxy *create_new_namespaces(unsigned long flags,
         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 @@ void free_nsproxy(struct nsproxy *ns)
                 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 6917e8edb48e..601bb361c235 100644
--- a/kernel/pid_namespace.c
+++ b/kernel/pid_namespace.c
@@ -349,8 +349,8 @@ static int pidns_install(struct nsproxy *nsproxy, void *ns)
         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;
 }