diff --git a/mm/mmap.c b/mm/mmap.c
index 6ea204c..1ec0f6e 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1009,8 +1009,7 @@
 	}
 
 	/* Check against address space limit. */
-	if ((mm->total_vm << PAGE_SHIFT) + len
-	    > current->signal->rlim[RLIMIT_AS].rlim_cur)
+	if (!may_expand_vm(mm, len >> PAGE_SHIFT))
 		return -ENOMEM;
 
 	if (accountable && (!(flags & MAP_NORESERVE) ||
@@ -1421,7 +1420,7 @@
 	struct rlimit *rlim = current->signal->rlim;
 
 	/* address space limit tests */
-	if (mm->total_vm + grow > rlim[RLIMIT_AS].rlim_cur >> PAGE_SHIFT)
+	if (!may_expand_vm(mm, grow))
 		return -ENOMEM;
 
 	/* Stack limit test */
@@ -1848,8 +1847,7 @@
 	}
 
 	/* Check against address space limits *after* clearing old maps... */
-	if ((mm->total_vm << PAGE_SHIFT) + len
-	    > current->signal->rlim[RLIMIT_AS].rlim_cur)
+	if (!may_expand_vm(mm, len >> PAGE_SHIFT))
 		return -ENOMEM;
 
 	if (mm->map_count > sysctl_max_map_count)
@@ -2019,3 +2017,19 @@
 	}
 	return new_vma;
 }
+
+/*
+ * Return true if the calling process may expand its vm space by the passed
+ * number of pages
+ */
+int may_expand_vm(struct mm_struct *mm, unsigned long npages)
+{
+	unsigned long cur = mm->total_vm;	/* pages */
+	unsigned long lim;
+
+	lim = current->signal->rlim[RLIMIT_AS].rlim_cur >> PAGE_SHIFT;
+
+	if (cur + npages > lim)
+		return 0;
+	return 1;
+}