Merge branch 'for-4.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup

Pull cgroup updates from Tejun Heo:
 "Nothing major. Two notable fixes are Li's second stab at fixing the
  long-standing race condition in the mount path and suppression of
  spurious warning from cgroup_get(). All other changes are trivial"

* 'for-4.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cgroup: mark cgroup_get() with __maybe_unused
  cgroup: avoid attaching a cgroup root to two different superblocks, take 2
  cgroup: fix spurious warnings on cgroup_is_dead() from cgroup_sk_alloc()
  cgroup: move cgroup_subsys_state parent field for cache locality
  cpuset: Remove cpuset_update_active_cpus()'s parameter.
  cgroup: switch to BUG_ON()
  cgroup: drop duplicate header nsproxy.h
  kernel: convert css_set.refcount from atomic_t to refcount_t
  kernel: convert cgroup_namespace.count from atomic_t to refcount_t

3 files changed, 14 insertions, 10 deletions

diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h
index 6a3f850cabab..21745946cae1 100644
--- a/include/linux/cgroup-defs.h
+++ b/include/linux/cgroup-defs.h
@@ -13,6 +13,7 @@
 #include <linux/wait.h>
 #include <linux/mutex.h>
 #include <linux/rcupdate.h>
+#include <linux/refcount.h>
 #include <linux/percpu-refcount.h>
 #include <linux/percpu-rwsem.h>
 #include <linux/workqueue.h>
@@ -106,9 +107,6 @@ struct cgroup_subsys_state {
 	/* reference count - access via css_[try]get() and css_put() */
 	struct percpu_ref refcnt;
 
-	/* PI: the parent css */
-	struct cgroup_subsys_state *parent;
-
 	/* siblings list anchored at the parent's ->children */
 	struct list_head sibling;
 	struct list_head children;
@@ -138,6 +136,12 @@ struct cgroup_subsys_state {
 	/* percpu_ref killing and RCU release */
 	struct rcu_head rcu_head;
 	struct work_struct destroy_work;
+
+	/*
+	 * PI: the parent css.	Placed here for cache proximity to following
+	 * fields of the containing structure.
+	 */
+	struct cgroup_subsys_state *parent;
 };
 
 /*
@@ -156,7 +160,7 @@ struct css_set {
 	struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT];
 
 	/* reference count */
-	atomic_t refcount;
+	refcount_t refcount;
 
 	/* the default cgroup associated with this css_set */
 	struct cgroup *dfl_cgrp;
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index af9c86e958bd..ed2573e149fa 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -17,11 +17,11 @@
 #include <linux/seq_file.h>
 #include <linux/kernfs.h>
 #include <linux/jump_label.h>
-#include <linux/nsproxy.h>
 #include <linux/types.h>
 #include <linux/ns_common.h>
 #include <linux/nsproxy.h>
 #include <linux/user_namespace.h>
+#include <linux/refcount.h>
 
 #include <linux/cgroup-defs.h>
 
@@ -661,7 +661,7 @@ static inline void cgroup_sk_free(struct sock_cgroup_data *skcd) {}
 #endif	/* CONFIG_CGROUP_DATA */
 
 struct cgroup_namespace {
-	atomic_t		count;
+	refcount_t		count;
 	struct ns_common	ns;
 	struct user_namespace	*user_ns;
 	struct ucounts		*ucounts;
@@ -696,12 +696,12 @@ copy_cgroup_ns(unsigned long flags, struct user_namespace *user_ns,
 static inline void get_cgroup_ns(struct cgroup_namespace *ns)
 {
 	if (ns)
-		atomic_inc(&ns->count);
+		refcount_inc(&ns->count);
 }
 
 static inline void put_cgroup_ns(struct cgroup_namespace *ns)
 {
-	if (ns && atomic_dec_and_test(&ns->count))
+	if (ns && refcount_dec_and_test(&ns->count))
 		free_cgroup_ns(ns);
 }
 
diff --git a/include/linux/cpuset.h b/include/linux/cpuset.h
index 611fce58d670..119a3f9604b0 100644
--- a/include/linux/cpuset.h
+++ b/include/linux/cpuset.h
@@ -42,7 +42,7 @@ static inline void cpuset_dec(void)
 
 extern int cpuset_init(void);
 extern void cpuset_init_smp(void);
-extern void cpuset_update_active_cpus(bool cpu_online);
+extern void cpuset_update_active_cpus(void);
 extern void cpuset_cpus_allowed(struct task_struct *p, struct cpumask *mask);
 extern void cpuset_cpus_allowed_fallback(struct task_struct *p);
 extern nodemask_t cpuset_mems_allowed(struct task_struct *p);
@@ -155,7 +155,7 @@ static inline bool cpusets_enabled(void) { return false; }
 static inline int cpuset_init(void) { return 0; }
 static inline void cpuset_init_smp(void) {}
 
-static inline void cpuset_update_active_cpus(bool cpu_online)
+static inline void cpuset_update_active_cpus(void)
 {
 	partition_sched_domains(1, NULL, NULL);
 }