diff --git a/include/linux/pci.h b/include/linux/pci.h
index fafd8020c6d7f1f7a02b82199874d11b6b0870dd..0239f12d0ba9a2eb19c7b377eff699b816f4efad 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1994,14 +1994,13 @@ int pci_iobar_pfn(struct pci_dev *pdev, int bar, struct vm_area_struct *vma);
  * These helpers provide future and backwards compatibility
  * for accessing popular PCI BAR info
  */
-#define pci_resource_start(dev, bar)	((dev)->resource[(bar)].start)
-#define pci_resource_end(dev, bar)	((dev)->resource[(bar)].end)
-#define pci_resource_flags(dev, bar)	((dev)->resource[(bar)].flags)
-#define pci_resource_len(dev,bar) \
-	((pci_resource_end((dev), (bar)) == 0) ? 0 :	\
-							\
-	 (pci_resource_end((dev), (bar)) -		\
-	  pci_resource_start((dev), (bar)) + 1))
+#define pci_resource_n(dev, bar)	(&(dev)->resource[(bar)])
+#define pci_resource_start(dev, bar)	(pci_resource_n(dev, bar)->start)
+#define pci_resource_end(dev, bar)	(pci_resource_n(dev, bar)->end)
+#define pci_resource_flags(dev, bar)	(pci_resource_n(dev, bar)->flags)
+#define pci_resource_len(dev,bar)					\
+	(pci_resource_end((dev), (bar)) ? 				\
+	 resource_size(pci_resource_n((dev), (bar))) : 0)
 
 /*
  * Similar to the helpers above, these manipulate per-pci_dev