Write dma_length of each leader with the combined lengths of
the mergable followers. */
-#define SG_ENT_VIRT_ADDRESS(SG) (page_address((SG)->page) + (SG)->offset)
+#define SG_ENT_VIRT_ADDRESS(SG) (sg_virt((SG)))
#define SG_ENT_PHYS_ADDRESS(SG) __pa(SG_ENT_VIRT_ADDRESS(SG))
static void