freezer_cg: remove redundant check in freezer_can_attach()
It is sufficient to check if @task is frozen, and no need to check if the
original freezer is frozen.
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 7f54d1c..e9c856a 100644
--- a/kernel/cgroup_freezer.c
+++ b/kernel/cgroup_freezer.c
@@ -162,9 +162,13 @@
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 @@
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)