diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index abb66a2..aeb2393 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2844,12 +2844,12 @@
  */
 int mem_cgroup_try_charge_swapin(struct mm_struct *mm,
 				 struct page *page,
-				 gfp_t mask, struct mem_cgroup **ptr)
+				 gfp_t mask, struct mem_cgroup **memcgp)
 {
 	struct mem_cgroup *memcg;
 	int ret;
 
-	*ptr = NULL;
+	*memcgp = NULL;
 
 	if (mem_cgroup_disabled())
 		return 0;
@@ -2867,27 +2867,27 @@
 	memcg = try_get_mem_cgroup_from_page(page);
 	if (!memcg)
 		goto charge_cur_mm;
-	*ptr = memcg;
-	ret = __mem_cgroup_try_charge(NULL, mask, 1, ptr, true);
+	*memcgp = memcg;
+	ret = __mem_cgroup_try_charge(NULL, mask, 1, memcgp, true);
 	css_put(&memcg->css);
 	return ret;
 charge_cur_mm:
 	if (unlikely(!mm))
 		mm = &init_mm;
-	return __mem_cgroup_try_charge(mm, mask, 1, ptr, true);
+	return __mem_cgroup_try_charge(mm, mask, 1, memcgp, true);
 }
 
 static void
-__mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr,
+__mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *memcg,
 					enum charge_type ctype)
 {
 	if (mem_cgroup_disabled())
 		return;
-	if (!ptr)
+	if (!memcg)
 		return;
-	cgroup_exclude_rmdir(&ptr->css);
+	cgroup_exclude_rmdir(&memcg->css);
 
-	__mem_cgroup_commit_charge_lrucare(page, ptr, ctype);
+	__mem_cgroup_commit_charge_lrucare(page, memcg, ctype);
 	/*
 	 * Now swap is on-memory. This means this page may be
 	 * counted both as mem and swap....double count.
@@ -2897,21 +2897,22 @@
 	 */
 	if (do_swap_account && PageSwapCache(page)) {
 		swp_entry_t ent = {.val = page_private(page)};
+		struct mem_cgroup *swap_memcg;
 		unsigned short id;
-		struct mem_cgroup *memcg;
 
 		id = swap_cgroup_record(ent, 0);
 		rcu_read_lock();
-		memcg = mem_cgroup_lookup(id);
-		if (memcg) {
+		swap_memcg = mem_cgroup_lookup(id);
+		if (swap_memcg) {
 			/*
 			 * This recorded memcg can be obsolete one. So, avoid
 			 * calling css_tryget
 			 */
-			if (!mem_cgroup_is_root(memcg))
-				res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
-			mem_cgroup_swap_statistics(memcg, false);
-			mem_cgroup_put(memcg);
+			if (!mem_cgroup_is_root(swap_memcg))
+				res_counter_uncharge(&swap_memcg->memsw,
+						     PAGE_SIZE);
+			mem_cgroup_swap_statistics(swap_memcg, false);
+			mem_cgroup_put(swap_memcg);
 		}
 		rcu_read_unlock();
 	}
@@ -2920,13 +2921,14 @@
 	 * So, rmdir()->pre_destroy() can be called while we do this charge.
 	 * In that case, we need to call pre_destroy() again. check it here.
 	 */
-	cgroup_release_and_wakeup_rmdir(&ptr->css);
+	cgroup_release_and_wakeup_rmdir(&memcg->css);
 }
 
-void mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr)
+void mem_cgroup_commit_charge_swapin(struct page *page,
+				     struct mem_cgroup *memcg)
 {
-	__mem_cgroup_commit_charge_swapin(page, ptr,
-					MEM_CGROUP_CHARGE_TYPE_MAPPED);
+	__mem_cgroup_commit_charge_swapin(page, memcg,
+					  MEM_CGROUP_CHARGE_TYPE_MAPPED);
 }
 
 void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *memcg)
@@ -3255,14 +3257,14 @@
  * page belongs to.
  */
 int mem_cgroup_prepare_migration(struct page *page,
-	struct page *newpage, struct mem_cgroup **ptr, gfp_t gfp_mask)
+	struct page *newpage, struct mem_cgroup **memcgp, gfp_t gfp_mask)
 {
 	struct mem_cgroup *memcg = NULL;
 	struct page_cgroup *pc;
 	enum charge_type ctype;
 	int ret = 0;
 
-	*ptr = NULL;
+	*memcgp = NULL;
 
 	VM_BUG_ON(PageTransHuge(page));
 	if (mem_cgroup_disabled())
@@ -3313,10 +3315,10 @@
 	if (!memcg)
 		return 0;
 
-	*ptr = memcg;
-	ret = __mem_cgroup_try_charge(NULL, gfp_mask, 1, ptr, false);
+	*memcgp = memcg;
+	ret = __mem_cgroup_try_charge(NULL, gfp_mask, 1, memcgp, false);
 	css_put(&memcg->css);/* drop extra refcnt */
-	if (ret || *ptr == NULL) {
+	if (ret || *memcgp == NULL) {
 		if (PageAnon(page)) {
 			lock_page_cgroup(pc);
 			ClearPageCgroupMigration(pc);