cgroup: cpuset: remove unused variable

index 266f10cb7222..784f9480e054 100644
@@ -1498,10 +1498,8 @@ static int cpuset_can_attach(struct cgroup_taskset *tset)
 static void cpuset_cancel_attach(struct cgroup_taskset *tset)
 {
 	struct cgroup_subsys_state *css;
-	struct cpuset *cs;
 
 	cgroup_taskset_first(tset, &css);
-	cs = css_cs(css);
 
 	mutex_lock(&cpuset_mutex);
 	css_cs(css)->attach_in_progress--;