xen/swiotlb: simplify range_straddles_page_boundary()

	return xen_phys_to_bus(virt_to_phys(address));

}

static int check_pages_physically_contiguous(unsigned long xen_pfn,

					     unsigned int offset,

					     size_t length)

static inline int range_straddles_page_boundary(phys_addr_t p, size_t size)

{

	unsigned long next_bfn;

	int i;

	int nr_pages;

	unsigned long next_bfn, xen_pfn = XEN_PFN_DOWN(p);

	unsigned int i, nr_pages = XEN_PFN_UP(xen_offset_in_page(p) + size);

	next_bfn = pfn_to_bfn(xen_pfn);

	nr_pages = (offset + length + XEN_PAGE_SIZE-1) >> XEN_PAGE_SHIFT;

	for (i = 1; i < nr_pages; i++) {

	for (i = 1; i < nr_pages; i++)

		if (pfn_to_bfn(++xen_pfn) != ++next_bfn)

			return 0;

	}

			return 1;

}

static inline int range_straddles_page_boundary(phys_addr_t p, size_t size)

{

	unsigned long xen_pfn = XEN_PFN_DOWN(p);

	unsigned int offset = p & ~XEN_PAGE_MASK;

	if (offset + size <= XEN_PAGE_SIZE)

	return 0;

	if (check_pages_physically_contiguous(xen_pfn, offset, size))

		return 0;

	return 1;

}

static int is_xen_swiotlb_buffer(dma_addr_t dma_addr)