diff --git a/drivers/xen/biomerge.c b/drivers/xen/biomerge.c
index 4da69dbf7dca..1bdd02a6d6ac 100644
--- a/drivers/xen/biomerge.c
+++ b/drivers/xen/biomerge.c
@@ -10,8 +10,7 @@ bool xen_biovec_phys_mergeable(const struct bio_vec *vec1,
 	unsigned long bfn1 = pfn_to_bfn(page_to_pfn(vec1->bv_page));
 	unsigned long bfn2 = pfn_to_bfn(page_to_pfn(vec2->bv_page));
 
-	return __BIOVEC_PHYS_MERGEABLE(vec1, vec2) &&
-		((bfn1 == bfn2) || ((bfn1+1) == bfn2));
+	return bfn1 + PFN_DOWN(vec1->bv_offset + vec1->bv_len) == bfn2;
 #else
 	/*
 	 * XXX: Add support for merging bio_vec when using different page