/* this lookup is complicated by the fact that the bitmap sb might be exactly 1 page (e.g., x86) or less than 1 page  */
static struct page* filemap_get_page(struct bitmap *bitmap, unsigned long chunk)
/* this lookup is complicated by the fact that the bitmap sb might be exactly 1 page (e.g., x86) or less than 1 page  */
static struct page* filemap_get_page(struct bitmap *bitmap, unsigned long chunk)
{
	if (file_page_index(bitmap, chunk) >= bitmap->file_pages) return NULL;
	return bitmap->filemap[file_page_index(bitmap, chunk)
			       - file_page_index(bitmap, 0)];
}