Task Control Groups: add cgroup_clone() interface

Add support for cgroup_clone(), a way to create new cgroups intended to
be used for systems such as namespace unsharing.  A new subsystem callback,
post_clone(), is added to allow subsystems to automatically configure cloned
cgroups.

Signed-off-by: Paul Menage <menage@google.com>
Cc: Serge E. Hallyn <serue@us.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 3 insertions, 0 deletions

diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 792ad74be17..b21cf093ac6 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -182,6 +182,7 @@ struct cgroup_subsys {
         void (*exit)(struct cgroup_subsys *ss, struct task_struct *task);
         int (*populate)(struct cgroup_subsys *ss,
                         struct cgroup *cont);
+        void (*post_clone)(struct cgroup_subsys *ss, struct cgroup *cont);
         void (*bind)(struct cgroup_subsys *ss, struct cgroup *root);
         int subsys_id;
         int active;
@@ -221,6 +222,8 @@ static inline struct cgroup* task_cgroup(struct task_struct *task,
 
 int cgroup_path(const struct cgroup *cont, char *buf, int buflen);
 
+int cgroup_clone(struct task_struct *tsk, struct cgroup_subsys *ss);
+
 #else /* !CONFIG_CGROUPS */
 
 static inline int cgroup_init_early(void) { return 0; }