mm: memcg: clean up mm_match_cgroup() signature

It really should return a boolean for match/no match.  And since it takes
a memcg, not a cgroup, fix that parameter name as well.

[akpm@linux-foundation.org: mm_match_cgroup() is not a macro]
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/memcontrol.h

@@ -84,14 +84,14 @@ extern struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg);
 extern struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont);
 
 static inline
-int mm_match_cgroup(const struct mm_struct *mm, const struct mem_cgroup *cgroup)
+bool mm_match_cgroup(const struct mm_struct *mm, const struct mem_cgroup *memcg)
 {
-	struct mem_cgroup *memcg;
-	int match;
+	struct mem_cgroup *task_memcg;
+	bool match;
 
 	rcu_read_lock();
-	memcg = mem_cgroup_from_task(rcu_dereference((mm)->owner));
-	match = __mem_cgroup_same_or_subtree(cgroup, memcg);
+	task_memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
+	match = __mem_cgroup_same_or_subtree(memcg, task_memcg);
 	rcu_read_unlock();
 	return match;
 }
@@ -258,10 +258,10 @@ static inline struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm
 	return NULL;
 }
 
-static inline int mm_match_cgroup(struct mm_struct *mm,
+static inline bool mm_match_cgroup(struct mm_struct *mm,
 		struct mem_cgroup *memcg)
 {
-	return 1;
+	return true;
 }
 
 static inline int task_in_mem_cgroup(struct task_struct *task,