freezer_cg: remove redundant check in freezer_can_attach()

[linux-2.6-omap-h63xx.git] / kernel / cgroup_freezer.c

diff --git a/kernel/cgroup_freezer.c b/kernel/cgroup_freezer.c
index e95056954498e42e2f225216eaa0cd6286b6f7b6..e9c856a265c962abfd885e912bfe010893e2b259 100644 (file)
--- a/kernel/cgroup_freezer.c
+++ b/kernel/cgroup_freezer.c
@@ -162,9 +162,13 @@ static int freezer_can_attach(struct cgroup_subsys *ss,
                              struct task_struct *task)
 {
        struct freezer *freezer;
-       int retval;
 
-       /* Anything frozen can't move or be moved to/from */
+       /*
+        * Anything frozen can't move or be moved to/from.
+        *
+        * Since orig_freezer->state == FROZEN means that @task has been
+        * frozen, so it's sufficient to check the latter condition.
+        */
 
        if (is_task_frozen_enough(task))
                return -EBUSY;
@@ -173,13 +177,7 @@ static int freezer_can_attach(struct cgroup_subsys *ss,
        if (freezer->state == CGROUP_FROZEN)
                return -EBUSY;
 
-       retval = 0;
-       task_lock(task);
-       freezer = task_freezer(task);
-       if (freezer->state == CGROUP_FROZEN)
-               retval = -EBUSY;
-       task_unlock(task);
-       return retval;
+       return 0;
 }
 
 static void freezer_fork(struct cgroup_subsys *ss, struct task_struct *task)
@@ -190,8 +188,9 @@ static void freezer_fork(struct cgroup_subsys *ss, struct task_struct *task)
        freezer = task_freezer(task);
        task_unlock(task);
 
-       BUG_ON(freezer->state == CGROUP_FROZEN);
        spin_lock_irq(&freezer->lock);
+       BUG_ON(freezer->state == CGROUP_FROZEN);
+
        /* Locking avoids race with FREEZING -> THAWED transitions. */
        if (freezer->state == CGROUP_FREEZING)
                freeze_task(task, true);