freezer_cg: use thaw_process() in unfreeze_cgroup()

Don't duplicate the implementation of thaw_process().

[[e-mail]: make __thaw_process() static]
Signed-off-by: Li Zefan <[e-mail]>
Cc: Cedric Le Goater <[e-mail]>
Acked-by: Matt Helsley <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

include/linux/freezer.h

···
 	return !(p->flags & PF_FREEZER_NOSIG);
 }
 
-/*
- * Wake up a frozen process
- */
-extern int __thaw_process(struct task_struct *p);
-
 /* Takes and releases task alloc lock using task_lock() */
 extern int thaw_process(struct task_struct *p);
 

kernel/cgroup_freezer.c

···
 	return num_cant_freeze_now ? -EBUSY : 0;
 }
 
-static int unfreeze_cgroup(struct cgroup *cgroup, struct freezer *freezer)
+static void unfreeze_cgroup(struct cgroup *cgroup, struct freezer *freezer)
 {
 	struct cgroup_iter it;
 	struct task_struct *task;
 
 	cgroup_iter_start(cgroup, &it);
 	while ((task = cgroup_iter_next(cgroup, &it))) {
-		int do_wake;
-
-		task_lock(task);
-		do_wake = __thaw_process(task);
-		task_unlock(task);
-		if (do_wake)
-			wake_up_process(task);
+		thaw_process(task);
 	}
 	cgroup_iter_end(cgroup, &it);
-	freezer->state = CGROUP_THAWED;
 
-	return 0;
+	freezer->state = CGROUP_THAWED;
 }
 
 static int freezer_change_state(struct cgroup *cgroup,
···
 		}
 		/* state == FREEZING and goal_state == THAWED, so unfreeze */
 	case CGROUP_FROZEN:
-		retval = unfreeze_cgroup(cgroup, freezer);
+		unfreeze_cgroup(cgroup, freezer);
 		break;
 	default:
 		break;

kernel/freezer.c

···
 	}
 }
 
-/*
- * Wake up a frozen process
- *
- * task_lock() is needed to prevent the race with refrigerator() which may
- * occur if the freezing of tasks fails.  Namely, without the lock, if the
- * freezing of tasks failed, thaw_tasks() might have run before a task in
- * refrigerator() could call frozen_process(), in which case the task would be
- * frozen and no one would thaw it.
- */
-int __thaw_process(struct task_struct *p)
+static int __thaw_process(struct task_struct *p)
 {
 	if (frozen(p)) {
 		p->flags &= ~PF_FROZEN;
···
 	return 0;
 }
 
+/*
+ * Wake up a frozen process
+ *
+ * task_lock() is needed to prevent the race with refrigerator() which may
+ * occur if the freezing of tasks fails.  Namely, without the lock, if the
+ * freezing of tasks failed, thaw_tasks() might have run before a task in
+ * refrigerator() could call frozen_process(), in which case the task would be
+ * frozen and no one would thaw it.
+ */
 int thaw_process(struct task_struct *p)
 {
 	task_lock(p);