1 files changed, 41 insertions, 13 deletions

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index b24d7027b83..95362d15128 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -4230,20 +4230,8 @@ void cgroup_post_fork(struct task_struct *child)
  */
 void cgroup_exit(struct task_struct *tsk, int run_callbacks)
 {
-        int i;
         struct css_set *cg;
-
-        if (run_callbacks && need_forkexit_callback) {
-                /*
-                 * modular subsystems can't use callbacks, so no need to lock
-                 * the subsys array
-                 */
-                for (i = 0; i < CGROUP_BUILTIN_SUBSYS_COUNT; i++) {
-                        struct cgroup_subsys *ss = subsys[i];
-                        if (ss->exit)
-                                ss->exit(ss, tsk);
-                }
-        }
+        int i;
 
         /*
          * Unlink from the css_set task list if necessary.
@@ -4261,7 +4249,24 @@ void cgroup_exit(struct task_struct *tsk, int run_callbacks)
         task_lock(tsk);
         cg = tsk->cgroups;
         tsk->cgroups = &init_css_set;
+
+        if (run_callbacks && need_forkexit_callback) {
+                /*
+                 * modular subsystems can't use callbacks, so no need to lock
+                 * the subsys array
+                 */
+                for (i = 0; i < CGROUP_BUILTIN_SUBSYS_COUNT; i++) {
+                        struct cgroup_subsys *ss = subsys[i];
+                        if (ss->exit) {
+                                struct cgroup *old_cgrp =
+                                        rcu_dereference_raw(cg->subsys[i])->cgroup;
+                                struct cgroup *cgrp = task_cgroup(tsk, i);
+                                ss->exit(ss, cgrp, old_cgrp, tsk);
+                        }
+                }
+        }
         task_unlock(tsk);
+
         if (cg)
                 put_css_set_taskexit(cg);
 }
@@ -4813,6 +4818,29 @@ css_get_next(struct cgroup_subsys *ss, int id,
         return ret;
 }
 
+/*
+ * get corresponding css from file open on cgroupfs directory
+ */
+struct cgroup_subsys_state *cgroup_css_from_dir(struct file *f, int id)
+{
+        struct cgroup *cgrp;
+        struct inode *inode;
+        struct cgroup_subsys_state *css;
+
+        inode = f->f_dentry->d_inode;
+        /* check in cgroup filesystem dir */
+        if (inode->i_op != &cgroup_dir_inode_operations)
+                return ERR_PTR(-EBADF);
+
+        if (id < 0 || id >= CGROUP_SUBSYS_COUNT)
+                return ERR_PTR(-EINVAL);
+
+        /* get cgroup */
+        cgrp = __d_cgrp(f->f_dentry);
+        css = cgrp->subsys[id];
+        return css ? css : ERR_PTR(-ENOENT);
+}
+
 #ifdef CONFIG_CGROUP_DEBUG
 static struct cgroup_subsys_state *debug_create(struct cgroup_subsys *ss,
                                                    struct cgroup *cont)