1 files changed, 6 insertions, 56 deletions

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index e9aa2a51ca68..4a94b0be598d 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -178,7 +178,6 @@ static struct cftype cgroup_base_files[];
 static void cgroup_put(struct cgroup *cgrp);
 static int rebind_subsystems(struct cgroup_root *dst_root,
 			     unsigned int ss_mask);
-static void cgroup_destroy_css_killed(struct cgroup *cgrp);
 static int cgroup_destroy_locked(struct cgroup *cgrp);
 static int create_css(struct cgroup *cgrp, struct cgroup_subsys *ss);
 static void kill_css(struct cgroup_subsys_state *css);
@@ -4169,7 +4168,6 @@ static int online_css(struct cgroup_subsys_state *css)
 		ret = ss->css_online(css);
 	if (!ret) {
 		css->flags |= CSS_ONLINE;
-		css->cgroup->nr_css++;
 		rcu_assign_pointer(css->cgroup->subsys[ss->id], css);
 	}
 	return ret;
@@ -4189,7 +4187,6 @@ static void offline_css(struct cgroup_subsys_state *css)
 		ss->css_offline(css);
 
 	css->flags &= ~CSS_ONLINE;
-	css->cgroup->nr_css--;
 	RCU_INIT_POINTER(css->cgroup->subsys[ss->id], NULL);
 
 	wake_up_all(&css->cgroup->offline_waitq);
@@ -4374,39 +4371,18 @@ out_destroy:
 
 /*
  * This is called when the refcnt of a css is confirmed to be killed.
- * css_tryget_online() is now guaranteed to fail.
+ * css_tryget_online() is now guaranteed to fail.  Tell the subsystem to
+ * initate destruction and put the css ref from kill_css().
  */
 static void css_killed_work_fn(struct work_struct *work)
 {
 	struct cgroup_subsys_state *css =
 		container_of(work, struct cgroup_subsys_state, destroy_work);
-	struct cgroup *cgrp = css->cgroup;
 
 	mutex_lock(&cgroup_mutex);
-
-	/*
-	 * css_tryget_online() is guaranteed to fail now.  Tell subsystems
-	 * to initate destruction.
-	 */
 	offline_css(css);
-
-	/*
-	 * If @cgrp is marked dead, it's waiting for refs of all css's to
-	 * be disabled before proceeding to the second phase of cgroup
-	 * destruction.  If we are the last one, kick it off.
-	 */
-	if (!cgrp->nr_css && cgroup_is_dead(cgrp))
-		cgroup_destroy_css_killed(cgrp);
-
 	mutex_unlock(&cgroup_mutex);
 
-	/*
-	 * Put the css refs from kill_css().  Each css holds an extra
-	 * reference to the cgroup's dentry and cgroup removal proceeds
-	 * regardless of css refs.  On the last put of each css, whenever
-	 * that may be, the extra dentry ref is put so that dentry
-	 * destruction happens only after all css's are released.
-	 */
 	css_put(css);
 }
 
@@ -4518,11 +4494,7 @@ static int cgroup_destroy_locked(struct cgroup *cgrp)
 	 */
 	set_bit(CGRP_DEAD, &cgrp->flags);
 
-	/*
-	 * Initiate massacre of all css's.  cgroup_destroy_css_killed()
-	 * will be invoked to perform the rest of destruction once the
-	 * percpu refs of all css's are confirmed to be killed.
-	 */
+	/* initiate massacre of all css's */
 	for_each_css(css, ssid, cgrp)
 		kill_css(css);
 
@@ -4533,15 +4505,6 @@ static int cgroup_destroy_locked(struct cgroup *cgrp)
 	raw_spin_unlock(&release_list_lock);
 
 	/*
-	 * If @cgrp has css's attached, the second stage of cgroup
-	 * destruction is kicked off from css_killed_work_fn() after the
-	 * refs of all attached css's are killed.  If @cgrp doesn't have
-	 * any css, we kick it off here.
-	 */
-	if (!cgrp->nr_css)
-		cgroup_destroy_css_killed(cgrp);
-
-	/*
 	 * Remove @cgrp directory along with the base files.  @cgrp has an
 	 * extra ref on its kn.
 	 */
@@ -4550,25 +4513,12 @@ static int cgroup_destroy_locked(struct cgroup *cgrp)
 	set_bit(CGRP_RELEASABLE, &cgrp->parent->flags);
 	check_for_release(cgrp->parent);
 
+	/* put the base reference */
+	cgroup_put(cgrp);
+
 	return 0;
 };
 
-/**
- * cgroup_destroy_css_killed - the second step of cgroup destruction
- * @cgrp: the cgroup whose csses have just finished offlining
- *
- * This function is invoked from a work item for a cgroup which is being
- * destroyed after all css's are offlined and performs the rest of
- * destruction.  This is the second step of destruction described in the
- * comment above cgroup_destroy_locked().
- */
-static void cgroup_destroy_css_killed(struct cgroup *cgrp)
-{
-	lockdep_assert_held(&cgroup_mutex);
-
-	cgroup_put(cgrp);
-}
-
 static int cgroup_rmdir(struct kernfs_node *kn)
 {
 	struct cgroup *cgrp;