1 files changed, 40 insertions, 46 deletions

diff --git a/kernel/cgroup_freezer.c b/kernel/cgroup_freezer.c
index 5e828a2ca8e..fc0646b78a6 100644
--- a/kernel/cgroup_freezer.c
+++ b/kernel/cgroup_freezer.c
@@ -48,19 +48,17 @@ static inline struct freezer *task_freezer(struct task_struct *task)
 			    struct freezer, css);
 }
 
-static inline int __cgroup_freezing_or_frozen(struct task_struct *task)
+bool cgroup_freezing(struct task_struct *task)
 {
-	enum freezer_state state = task_freezer(task)->state;
-	return (state == CGROUP_FREEZING) || (state == CGROUP_FROZEN);
-}
+	enum freezer_state state;
+	bool ret;
 
-int cgroup_freezing_or_frozen(struct task_struct *task)
-{
-	int result;
-	task_lock(task);
-	result = __cgroup_freezing_or_frozen(task);
-	task_unlock(task);
-	return result;
+	rcu_read_lock();
+	state = task_freezer(task)->state;
+	ret = state == CGROUP_FREEZING || state == CGROUP_FROZEN;
+	rcu_read_unlock();
+
+	return ret;
 }
 
 /*
@@ -102,9 +100,6 @@ struct cgroup_subsys freezer_subsys;
  * freezer_can_attach():
  * cgroup_mutex (held by caller of can_attach)
  *
- * cgroup_freezing_or_frozen():
- * task->alloc_lock (to get task's cgroup)
- *
  * freezer_fork() (preserving fork() performance means can't take cgroup_mutex):
  * freezer->lock
  *  sighand->siglock (if the cgroup is freezing)
@@ -130,7 +125,7 @@ struct cgroup_subsys freezer_subsys;
  *   write_lock css_set_lock (cgroup iterator start)
  *    task->alloc_lock
  *   read_lock css_set_lock (cgroup iterator start)
- *    task->alloc_lock (inside thaw_process(), prevents race with refrigerator())
+ *    task->alloc_lock (inside __thaw_task(), prevents race with refrigerator())
  *     sighand->siglock
  */
 static struct cgroup_subsys_state *freezer_create(struct cgroup_subsys *ss,
@@ -150,7 +145,18 @@ static struct cgroup_subsys_state *freezer_create(struct cgroup_subsys *ss,
 static void freezer_destroy(struct cgroup_subsys *ss,
 			    struct cgroup *cgroup)
 {
-	kfree(cgroup_freezer(cgroup));
+	struct freezer *freezer = cgroup_freezer(cgroup);
+
+	if (freezer->state != CGROUP_THAWED)
+		atomic_dec(&system_freezing_cnt);
+	kfree(freezer);
+}
+
+/* task is frozen or will freeze immediately when next it gets woken */
+static bool is_task_frozen_enough(struct task_struct *task)
+{
+	return frozen(task) ||
+		(task_is_stopped_or_traced(task) && freezing(task));
 }
 
 /*
@@ -160,13 +166,17 @@ static void freezer_destroy(struct cgroup_subsys *ss,
  */
 static int freezer_can_attach(struct cgroup_subsys *ss,
 			      struct cgroup *new_cgroup,
-			      struct task_struct *task)
+			      struct cgroup_taskset *tset)
 {
 	struct freezer *freezer;
+	struct task_struct *task;
 
 	/*
 	 * Anything frozen can't move or be moved to/from.
 	 */
+	cgroup_taskset_for_each(task, new_cgroup, tset)
+		if (cgroup_freezing(task))
+			return -EBUSY;
 
 	freezer = cgroup_freezer(new_cgroup);
 	if (freezer->state != CGROUP_THAWED)
@@ -175,17 +185,6 @@ static int freezer_can_attach(struct cgroup_subsys *ss,
 	return 0;
 }
 
-static int freezer_can_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
-{
-	rcu_read_lock();
-	if (__cgroup_freezing_or_frozen(tsk)) {
-		rcu_read_unlock();
-		return -EBUSY;
-	}
-	rcu_read_unlock();
-	return 0;
-}
-
 static void freezer_fork(struct cgroup_subsys *ss, struct task_struct *task)
 {
 	struct freezer *freezer;
@@ -213,7 +212,7 @@ static void freezer_fork(struct cgroup_subsys *ss, struct task_struct *task)
 
 	/* Locking avoids race with FREEZING -> THAWED transitions. */
 	if (freezer->state == CGROUP_FREEZING)
-		freeze_task(task, true);
+		freeze_task(task);
 	spin_unlock_irq(&freezer->lock);
 }
 
@@ -231,7 +230,7 @@ static void update_if_frozen(struct cgroup *cgroup,
 	cgroup_iter_start(cgroup, &it);
 	while ((task = cgroup_iter_next(cgroup, &it))) {
 		ntotal++;
-		if (frozen(task))
+		if (freezing(task) && is_task_frozen_enough(task))
 			nfrozen++;
 	}
 
@@ -279,12 +278,11 @@ static int try_to_freeze_cgroup(struct cgroup *cgroup, struct freezer *freezer)
 	struct task_struct *task;
 	unsigned int num_cant_freeze_now = 0;
 
-	freezer->state = CGROUP_FREEZING;
 	cgroup_iter_start(cgroup, &it);
 	while ((task = cgroup_iter_next(cgroup, &it))) {
-		if (!freeze_task(task, true))
+		if (!freeze_task(task))
 			continue;
-		if (frozen(task))
+		if (is_task_frozen_enough(task))
 			continue;
 		if (!freezing(task) && !freezer_should_skip(task))
 			num_cant_freeze_now++;
@@ -300,12 +298,9 @@ static void unfreeze_cgroup(struct cgroup *cgroup, struct freezer *freezer)
 	struct task_struct *task;
 
 	cgroup_iter_start(cgroup, &it);
-	while ((task = cgroup_iter_next(cgroup, &it))) {
-		thaw_process(task);
-	}
+	while ((task = cgroup_iter_next(cgroup, &it)))
+		__thaw_task(task);
 	cgroup_iter_end(cgroup, &it);
-
-	freezer->state = CGROUP_THAWED;
 }
 
 static int freezer_change_state(struct cgroup *cgroup,
@@ -319,20 +314,24 @@ static int freezer_change_state(struct cgroup *cgroup,
 	spin_lock_irq(&freezer->lock);
 
 	update_if_frozen(cgroup, freezer);
-	if (goal_state == freezer->state)
-		goto out;
 
 	switch (goal_state) {
 	case CGROUP_THAWED:
+		if (freezer->state != CGROUP_THAWED)
+			atomic_dec(&system_freezing_cnt);
+		freezer->state = CGROUP_THAWED;
 		unfreeze_cgroup(cgroup, freezer);
 		break;
 	case CGROUP_FROZEN:
+		if (freezer->state == CGROUP_THAWED)
+			atomic_inc(&system_freezing_cnt);
+		freezer->state = CGROUP_FREEZING;
 		retval = try_to_freeze_cgroup(cgroup, freezer);
 		break;
 	default:
 		BUG();
 	}
-out:
+
 	spin_unlock_irq(&freezer->lock);
 
 	return retval;
@@ -381,10 +380,5 @@ struct cgroup_subsys freezer_subsys = {
 	.populate	= freezer_populate,
 	.subsys_id	= freezer_subsys_id,
 	.can_attach	= freezer_can_attach,
-	.can_attach_task = freezer_can_attach_task,
-	.pre_attach	= NULL,
-	.attach_task	= NULL,
-	.attach		= NULL,
 	.fork		= freezer_fork,
-	.exit		= NULL,
 };