From: Tejun Heo <tj@kernel.org>
Date: Fri, 11 Aug 2017 05:49:01 -0700
Subject: cgroup: misc changes
Patch-mainline: v4.14-rc1
Git-commit: 3e48930cc74f0c212ee1838f89ad0ca7fcf2fea1
References: bsc#1109837

Misc trivial changes to prepare for future changes.  No functional
difference.

* Expose cgroup_get(), cgroup_tryget() and cgroup_parent().

* Implement task_dfl_cgroup() which dereferences css_set->dfl_cgrp.

* Rename cgroup_stats_show() to cgroup_stat_show() for consistency
  with the file name.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 include/linux/cgroup.h |   24 ++++++++++++++++++++++++
 kernel/cgroup/cgroup.c |   19 -------------------
 2 files changed, 24 insertions(+), 19 deletions(-)

--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -388,6 +388,16 @@ static inline void css_put_many(struct c
 		percpu_ref_put_many(&css->refcnt, n);
 }
 
+static inline void cgroup_get(struct cgroup *cgrp)
+{
+	css_get(&cgrp->self);
+}
+
+static inline bool cgroup_tryget(struct cgroup *cgrp)
+{
+	return css_tryget(&cgrp->self);
+}
+
 static inline void cgroup_put(struct cgroup *cgrp)
 {
 	css_put(&cgrp->self);
@@ -500,6 +510,20 @@ static inline struct cgroup *task_cgroup
 	return task_css(task, subsys_id)->cgroup;
 }
 
+static inline struct cgroup *task_dfl_cgroup(struct task_struct *task)
+{
+	return task_css_set(task)->dfl_cgrp;
+}
+
+static inline struct cgroup *cgroup_parent(struct cgroup *cgrp)
+{
+	struct cgroup_subsys_state *parent_css = cgrp->self.parent;
+
+	if (parent_css)
+		return container_of(parent_css, struct cgroup, self);
+	return NULL;
+}
+
 /**
  * cgroup_is_descendant - test ancestry
  * @cgrp: the cgroup to be tested
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -316,15 +316,6 @@ static void cgroup_idr_remove(struct idr
 	spin_unlock_bh(&cgroup_idr_lock);
 }
 
-static struct cgroup *cgroup_parent(struct cgroup *cgrp)
-{
-	struct cgroup_subsys_state *parent_css = cgrp->self.parent;
-
-	if (parent_css)
-		return container_of(parent_css, struct cgroup, self);
-	return NULL;
-}
-
 /* subsystems visibly enabled on a cgroup */
 static u16 cgroup_control(struct cgroup *cgrp)
 {
@@ -436,22 +427,12 @@ out_unlock:
 	return css;
 }
 
-static void __maybe_unused cgroup_get(struct cgroup *cgrp)
-{
-	css_get(&cgrp->self);
-}
-
 static void cgroup_get_live(struct cgroup *cgrp)
 {
 	WARN_ON_ONCE(cgroup_is_dead(cgrp));
 	css_get(&cgrp->self);
 }
 
-static bool cgroup_tryget(struct cgroup *cgrp)
-{
-	return css_tryget(&cgrp->self);
-}
-
 struct cgroup_subsys_state *of_css(struct kernfs_open_file *of)
 {
 	struct cgroup *cgrp = of->kn->parent->priv;