[PATCH 1/5] cgroup: Inline cgroup_has_tasks() in cgroup.h

[Tejun Heo]

cpuset reads cs->css.cgroup->nr_populated_csets directly in two places to
test whether a cgroup has tasks. cgroup.c already has a matching helper,
cgroup_has_tasks(). Move it to cgroup.h as static inline and use that
instead. This is to prepare for relocation of cgroup->nr_populated_csets. No
semantic change.

Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
---
 include/linux/cgroup.h    | 5 +++++
 kernel/cgroup/cgroup.c    | 5 -----
 kernel/cgroup/cpuset-v1.c | 2 +-
 kernel/cgroup/cpuset.c    | 2 +-
 4 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index e52160e85af4..ceb87507667e 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -639,6 +639,11 @@ static inline bool task_under_cgroup_hierarchy(struct task_struct *task,
 	return cgroup_is_descendant(cset->dfl_cgrp, ancestor);
 }
 
+static inline bool cgroup_has_tasks(struct cgroup *cgrp)
+{
+	return cgrp->nr_populated_csets;
+}
+
 /* no synchronization, the result can only be used as a hint */
 static inline bool cgroup_is_populated(struct cgroup *cgrp)
 {
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index bd10a7e2f9c5..7a94c2ea1036 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -376,11 +376,6 @@ static void cgroup_idr_remove(struct idr *idr, int id)
 	spin_unlock_bh(&cgroup_idr_lock);
 }
 
-static bool cgroup_has_tasks(struct cgroup *cgrp)
-{
-	return cgrp->nr_populated_csets;
-}
-
 static bool cgroup_is_threaded(struct cgroup *cgrp)
 {
 	return cgrp->dom_cgrp != cgrp;
diff --git a/kernel/cgroup/cpuset-v1.c b/kernel/cgroup/cpuset-v1.c
index 7308e9b02495..3e9968dd91e9 100644
--- a/kernel/cgroup/cpuset-v1.c
+++ b/kernel/cgroup/cpuset-v1.c
@@ -312,7 +312,7 @@ void cpuset1_hotplug_update_tasks(struct cpuset *cs,
 	 * This is full cgroup operation which will also call back into
 	 * cpuset. Execute it asynchronously using workqueue.
 	 */
-	if (is_empty && cs->css.cgroup->nr_populated_csets &&
+	if (is_empty && cgroup_has_tasks(cs->css.cgroup) &&
 	    css_tryget_online(&cs->css)) {
 		struct cpuset_remove_tasks_struct *s;
 
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index e3a081a07c6d..a76006b62b9c 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -432,7 +432,7 @@ static inline bool partition_is_populated(struct cpuset *cs,
 	 * nr_populated_domain_children may include populated
 	 * csets from descendants that are partitions.
 	 */
-	if (cs->css.cgroup->nr_populated_csets ||
+	if (cgroup_has_tasks(cs->css.cgroup) ||
 	    cs->attach_in_progress)
 		return true;
 
-- 
2.54.0