cgroup: make task iterators deal with cgroup_subsys_state instead of cgroup

cgroup is in the process of converting to css (cgroup_subsys_state)
from cgroup as the principal subsystem interface handle.  This is
mostly to prepare for the unified hierarchy support where css's will
be created and destroyed dynamically but also helps cleaning up
subsystem implementations as css is usually what they are interested
in anyway.

This patch converts task iterators to deal with css instead of cgroup.
Note that under unified hierarchy, different sets of tasks will be
considered belonging to a given cgroup depending on the subsystem in
question and making the iterators deal with css instead cgroup
provides them with enough information about the iteration.

While at it, fix several function comment formats in cpuset.c.

This patch doesn't introduce any behavior differences.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Matt Helsley <matthltc@us.ibm.com>

1 files changed, 12 insertions, 14 deletions

diff --git a/kernel/cgroup_freezer.c b/kernel/cgroup_freezer.c
index e0ab9bfd679a..5cd2b6d55243 100644
--- a/kernel/cgroup_freezer.c
+++ b/kernel/cgroup_freezer.c
@@ -258,7 +258,7 @@ static void update_if_frozen(struct cgroup_subsys_state *css)
 {
 	struct freezer *freezer = css_freezer(css);
 	struct cgroup_subsys_state *pos;
-	struct cgroup_task_iter it;
+	struct css_task_iter it;
 	struct task_struct *task;
 
 	WARN_ON_ONCE(!rcu_read_lock_held());
@@ -279,9 +279,9 @@ static void update_if_frozen(struct cgroup_subsys_state *css)
 	}
 
 	/* are all tasks frozen? */
-	cgroup_task_iter_start(css->cgroup, &it);
+	css_task_iter_start(css, &it);
 
-	while ((task = cgroup_task_iter_next(&it))) {
+	while ((task = css_task_iter_next(&it))) {
 		if (freezing(task)) {
 			/*
 			 * freezer_should_skip() indicates that the task
@@ -296,7 +296,7 @@ static void update_if_frozen(struct cgroup_subsys_state *css)
 
 	freezer->state |= CGROUP_FROZEN;
 out_iter_end:
-	cgroup_task_iter_end(&it);
+	css_task_iter_end(&it);
 out_unlock:
 	spin_unlock_irq(&freezer->lock);
 }
@@ -322,26 +322,24 @@ static int freezer_read(struct cgroup_subsys_state *css, struct cftype *cft,
 
 static void freeze_cgroup(struct freezer *freezer)
 {
-	struct cgroup *cgroup = freezer->css.cgroup;
-	struct cgroup_task_iter it;
+	struct css_task_iter it;
 	struct task_struct *task;
 
-	cgroup_task_iter_start(cgroup, &it);
-	while ((task = cgroup_task_iter_next(&it)))
+	css_task_iter_start(&freezer->css, &it);
+	while ((task = css_task_iter_next(&it)))
 		freeze_task(task);
-	cgroup_task_iter_end(&it);
+	css_task_iter_end(&it);
 }
 
 static void unfreeze_cgroup(struct freezer *freezer)
 {
-	struct cgroup *cgroup = freezer->css.cgroup;
-	struct cgroup_task_iter it;
+	struct css_task_iter it;
 	struct task_struct *task;
 
-	cgroup_task_iter_start(cgroup, &it);
-	while ((task = cgroup_task_iter_next(&it)))
+	css_task_iter_start(&freezer->css, &it);
+	while ((task = css_task_iter_next(&it)))
 		__thaw_task(task);
-	cgroup_task_iter_end(&it);
+	css_task_iter_end(&it);
 }
 
 /**