diff --git a/arch/alpha/kernel/pci-sysfs.c b/arch/alpha/kernel/pci-sysfs.c
index 5c29f1d2821c..8802f955256e 100644
--- a/arch/alpha/kernel/pci-sysfs.c
+++ b/arch/alpha/kernel/pci-sysfs.c
@@ -37,12 +37,16 @@ static int hose_mmap_page_range(struct pci_controller *hose,
 static int __pci_mmap_fits(struct pci_dev *pdev, int num,
 			   struct vm_area_struct *vma, int sparse)
 {
+	resource_size_t len = pci_resource_len(pdev, num);
 	unsigned long nr, start, size;
 	int shift = sparse ? 5 : 0;
 
+	if (!len)
+		return 0;
+
 	nr = vma_pages(vma);
 	start = vma->vm_pgoff;
-	size = ((pci_resource_len(pdev, num) - 1) >> (PAGE_SHIFT - shift)) + 1;
+	size = ((len - 1) >> (PAGE_SHIFT - shift)) + 1;
 
 	if (start < size && size - start >= nr)
 		return 1;