1 files changed, 47 insertions, 21 deletions

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index b24d7027b83c..e31b220a743d 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1813,10 +1813,8 @@ int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
 
         /* Update the css_set linked lists if we're using them */
         write_lock(&css_set_lock);
-        if (!list_empty(&tsk->cg_list)) {
-                list_del(&tsk->cg_list);
-                list_add(&tsk->cg_list, &newcg->tasks);
-        }
+        if (!list_empty(&tsk->cg_list))
+                list_move(&tsk->cg_list, &newcg->tasks);
         write_unlock(&css_set_lock);
 
         for_each_subsys(root, ss) {
@@ -3655,12 +3653,12 @@ again:
         spin_lock(&release_list_lock);
         set_bit(CGRP_REMOVED, &cgrp->flags);
         if (!list_empty(&cgrp->release_list))
-                list_del(&cgrp->release_list);
+                list_del_init(&cgrp->release_list);
         spin_unlock(&release_list_lock);
 
         cgroup_lock_hierarchy(cgrp->root);
         /* delete this cgroup from parent->children */
-        list_del(&cgrp->sibling);
+        list_del_init(&cgrp->sibling);
         cgroup_unlock_hierarchy(cgrp->root);
 
         d = dget(cgrp->dentry);
@@ -3879,7 +3877,7 @@ void cgroup_unload_subsys(struct cgroup_subsys *ss)
         subsys[ss->subsys_id] = NULL;
 
         /* remove subsystem from rootnode's list of subsystems */
-        list_del(&ss->sibling);
+        list_del_init(&ss->sibling);
 
         /*
          * disentangle the css from all css_sets attached to the dummytop. as
@@ -4230,20 +4228,8 @@ 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.
@@ -4253,7 +4239,7 @@ void cgroup_exit(struct task_struct *tsk, int run_callbacks)
         if (!list_empty(&tsk->cg_list)) {
                 write_lock(&css_set_lock);
                 if (!list_empty(&tsk->cg_list))
-                        list_del(&tsk->cg_list);
+                        list_del_init(&tsk->cg_list);
                 write_unlock(&css_set_lock);
         }
 
@@ -4261,7 +4247,24 @@ 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 +4816,29 @@ 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)