diff --git a/mm/sparse-vmemmap.c b/mm/sparse-vmemmap.c
index cd75b21..99c4f36 100644
--- a/mm/sparse-vmemmap.c
+++ b/mm/sparse-vmemmap.c
@@ -76,7 +76,7 @@
 		pte_t entry;
 		void *p = vmemmap_alloc_block(PAGE_SIZE, node);
 		if (!p)
-			return 0;
+			return NULL;
 		entry = pfn_pte(__pa(p) >> PAGE_SHIFT, PAGE_KERNEL);
 		set_pte_at(&init_mm, addr, pte, entry);
 	}
@@ -89,7 +89,7 @@
 	if (pmd_none(*pmd)) {
 		void *p = vmemmap_alloc_block(PAGE_SIZE, node);
 		if (!p)
-			return 0;
+			return NULL;
 		pmd_populate_kernel(&init_mm, pmd, p);
 	}
 	return pmd;
@@ -101,7 +101,7 @@
 	if (pud_none(*pud)) {
 		void *p = vmemmap_alloc_block(PAGE_SIZE, node);
 		if (!p)
-			return 0;
+			return NULL;
 		pud_populate(&init_mm, pud, p);
 	}
 	return pud;
@@ -113,7 +113,7 @@
 	if (pgd_none(*pgd)) {
 		void *p = vmemmap_alloc_block(PAGE_SIZE, node);
 		if (!p)
-			return 0;
+			return NULL;
 		pgd_populate(&init_mm, pgd, p);
 	}
 	return pgd;