[patch 20/50] cgroups: remove node_ prefix_from ns subsystem

[Chris Wright]

-stable review patch.  If anyone has any objections, please let us know.
---------------------

From: Cedric Le Goater <clg@xxxxxxxxxx>

upstream commit: 5c02b575780d0d785815a1e7b79a98edddee895a

This is a slight change in the namespace cgroup subsystem api.

The change is that previously when cgroup_clone() was called (currently
only from the unshare path in ns_proxy cgroup, you'd get a new group named
"node_$pid" whereas now you'll get a group named after just your pid.)

The only users who would notice it are those who are using the ns_proxy
cgroup subsystem to auto-create cgroups when namespaces are unshared -
something of an experimental feature, which I think really needs more
complete container/namespace support in order to be useful.  I suspect the
only users are Cedric and Serge, or maybe a few others on
containers@xxxxxxxxxxxxxxxxxxxxxxxxxxx  And in fact it would only be
noticed by the users who make the assumption about how the name is
generated, rather than getting it from the /proc/<pid>/cgroups file for
the process in question.

Whether the change is actually needed or not I'm fairly agnostic on, but I
guess it is more elegant to just use the pid as the new group name rather
than adding a fairly arbitrary "node_" prefix on the front.

[menage@xxxxxxxxxx: provided changelog]
Signed-off-by: Cedric Le Goater <clg@xxxxxxxxxx>
Cc: "Paul Menage" <menage@xxxxxxxxxx>
Cc: "Serge E. Hallyn" <serue@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Chris Wright <chrisw@xxxxxxxxxxxx>
---
 kernel/cgroup.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -2808,7 +2808,7 @@ int cgroup_clone(struct task_struct *tsk
 	cg = tsk->cgroups;
 	parent = task_cgroup(tsk, subsys->subsys_id);
 
-	snprintf(nodename, MAX_CGROUP_TYPE_NAMELEN, "node_%d", tsk->pid);
+	snprintf(nodename, MAX_CGROUP_TYPE_NAMELEN, "%d", tsk->pid);
 
 	/* Pin the hierarchy */
 	atomic_inc(&parent->root->sb->s_active);

-- 
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