1 files changed, 28 insertions, 35 deletions

diff --git a/kernel/cgroup_freezer.c b/kernel/cgroup_freezer.c
index 213c0351dad8..fcb93fca782d 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 +145,11 @@ 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 */
@@ -184,13 +183,7 @@ static int freezer_can_attach(struct cgroup_subsys *ss,
 
 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;
+        return cgroup_freezing(tsk) ? -EBUSY : 0;
 }
 
 static void freezer_fork(struct cgroup_subsys *ss, struct task_struct *task)
@@ -220,7 +213,7 @@ 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);
 }
 
@@ -238,7 +231,7 @@ static void update_if_frozen(struct cgroup *cgroup,
         cgroup_iter_start(cgroup, &it);
         while ((task = cgroup_iter_next(cgroup, &it))) {
                 ntotal++;
-                if (is_task_frozen_enough(task))
+                if (freezing(task) && is_task_frozen_enough(task))
                         nfrozen++;
         }
 
@@ -286,10 +279,9 @@ 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 (is_task_frozen_enough(task))
                         continue;
@@ -307,12 +299,9 @@ 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,
@@ -326,20 +315,24 @@ 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;