diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index e1ee6ad..b56bd74 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2475,7 +2475,7 @@
 
 	/* shmem */
 	if (PageSwapCache(page)) {
-		struct mem_cgroup *mem = NULL;
+		struct mem_cgroup *mem;
 
 		ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem);
 		if (!ret)
@@ -2501,6 +2501,8 @@
 	struct mem_cgroup *mem;
 	int ret;
 
+	*ptr = NULL;
+
 	if (mem_cgroup_disabled())
 		return 0;
 
@@ -2916,6 +2918,8 @@
 	enum charge_type ctype;
 	int ret = 0;
 
+	*ptr = NULL;
+
 	VM_BUG_ON(PageTransHuge(page));
 	if (mem_cgroup_disabled())
 		return 0;
@@ -3058,7 +3062,7 @@
 			    struct mm_struct *mm,
 			    gfp_t gfp_mask)
 {
-	struct mem_cgroup *mem = NULL;
+	struct mem_cgroup *mem;
 	int ret;
 
 	if (mem_cgroup_disabled())
diff --git a/mm/memory.c b/mm/memory.c
index 615be51..20d5f74 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2767,7 +2767,7 @@
 	swp_entry_t entry;
 	pte_t pte;
 	int locked;
-	struct mem_cgroup *ptr = NULL;
+	struct mem_cgroup *ptr;
 	int exclusive = 0;
 	int ret = 0;
 
diff --git a/mm/migrate.c b/mm/migrate.c
index 89e5c3f..b0406d7 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -633,7 +633,7 @@
 	struct page *newpage = get_new_page(page, private, &result);
 	int remap_swapcache = 1;
 	int charge = 0;
-	struct mem_cgroup *mem = NULL;
+	struct mem_cgroup *mem;
 	struct anon_vma *anon_vma = NULL;
 
 	if (!newpage)
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 71b42ec..039e616 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -880,7 +880,7 @@
 static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd,
 		unsigned long addr, swp_entry_t entry, struct page *page)
 {
-	struct mem_cgroup *ptr = NULL;
+	struct mem_cgroup *ptr;
 	spinlock_t *ptl;
 	pte_t *pte;
 	int ret = 1;