cgroup/cpuset: remove fetch_xcpus

Both fetch_xcpus and user_xcpus functions are used to retrieve the value
of exclusive_cpus. If exclusive_cpus is not set, cpus_allowed is the
implicit value used as exclusive in a local partition. I can not imagine
a scenario where effective_xcpus is not empty when exclusive_cpus is
empty. Therefore, I suggest removing the fetch_xcpus function.
Signed-off-by: Chen Ridong <chenridong@huawei.com>
Reviewed-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

kernel/cgroup/cpuset.c

@@ -771,13 +771,6 @@ static inline bool xcpus_empty(struct cpuset *cs)
 	       cpumask_empty(cs->exclusive_cpus);
 }
 
-static inline struct cpumask *fetch_xcpus(struct cpuset *cs)
-{
-	return !cpumask_empty(cs->exclusive_cpus) ? cs->exclusive_cpus :
-	       cpumask_empty(cs->effective_xcpus) ? cs->cpus_allowed
-						  : cs->effective_xcpus;
-}
-
 /*
  * cpusets_are_exclusive() - check if two cpusets are exclusive
  *
@@ -785,8 +778,8 @@ static inline struct cpumask *fetch_xcpus(struct cpuset *cs)
  */
 static inline bool cpusets_are_exclusive(struct cpuset *cs1, struct cpuset *cs2)
 {
-	struct cpumask *xcpus1 = fetch_xcpus(cs1);
-	struct cpumask *xcpus2 = fetch_xcpus(cs2);
+	struct cpumask *xcpus1 = user_xcpus(cs1);
+	struct cpumask *xcpus2 = user_xcpus(cs2);
 
 	if (cpumask_intersects(xcpus1, xcpus2))
 		return false;
@@ -2585,7 +2578,7 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
 		invalidate = true;
 		rcu_read_lock();
 		cpuset_for_each_child(cp, css, parent) {
-			struct cpumask *xcpus = fetch_xcpus(trialcs);
+			struct cpumask *xcpus = user_xcpus(trialcs);
 
 			if (is_partition_valid(cp) &&
 			    cpumask_intersects(xcpus, cp->effective_xcpus)) {