freezer_cg: simplify freezer_change_state()

Just call unfreeze_cgroup() if goal_state == THAWED, and call
try_to_freeze_cgroup() if goal_state == FROZEN.

No behavior has been changed.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Cedric Le Goater <clg@fr.ibm.com>
Acked-by: Matt Helsley <matthltc@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/kernel/cgroup_freezer.c b/kernel/cgroup_freezer.c
index 5e6d26b..7fa476f 100644 (file)
--- a/kernel/cgroup_freezer.c
+++ b/kernel/cgroup_freezer.c
@@ -296,27 +296,22 @@ static int freezer_change_state(struct cgroup *cgroup,
        int retval = 0;
 
        freezer = cgroup_freezer(cgroup);
+
        spin_lock_irq(&freezer->lock);
+
        update_freezer_state(cgroup, freezer);
        if (goal_state == freezer->state)
                goto out;
-       switch (freezer->state) {
+
+       switch (goal_state) {
        case CGROUP_THAWED:
-               retval = try_to_freeze_cgroup(cgroup, freezer);
+               unfreeze_cgroup(cgroup, freezer);
                break;
-       case CGROUP_FREEZING:
-               if (goal_state == CGROUP_FROZEN) {
-                       /* Userspace is retrying after
-                        * "/bin/echo FROZEN > freezer.state" returned -EBUSY */
-                       retval = try_to_freeze_cgroup(cgroup, freezer);
-                       break;
-               }
-               /* state == FREEZING and goal_state == THAWED, so unfreeze */
        case CGROUP_FROZEN:
-               unfreeze_cgroup(cgroup, freezer);
+               retval = try_to_freeze_cgroup(cgroup, freezer);
                break;
        default:
-               break;
+               BUG();
        }
 out:
        spin_unlock_irq(&freezer->lock);