int nr_pages, int flags)
 {
        grant_ref_t ref;
-       unsigned long buffer_mfn;
        unsigned int offset;
        unsigned int len = length;
        unsigned int bytes;
        int i;
 
        for (i = 0; i < nr_pages; i++) {
-               buffer_mfn = PFN_DOWN(arbitrary_virt_to_machine(addr).maddr);
                offset = offset_in_page(addr);
 
                bytes = PAGE_SIZE - offset;
 
                ref = gnttab_claim_grant_reference(gref_head);
                gnttab_grant_foreign_access_ref(ref, info->xbdev->otherend_id,
-                                               buffer_mfn, flags);
+                                               virt_to_gfn(addr), flags);
                seg[i].gref = ref;
                seg[i].offset = (__u16)offset;
                seg[i].length = (__u16)bytes;