addr &= ~(PAGE_SIZE - 1);
n = (len + PAGE_SIZE - 1) / PAGE_SIZE;
res = get_user_pages_fast(addr, n, (i->type & WRITE) != WRITE, pages);
addr &= ~(PAGE_SIZE - 1);
n = (len + PAGE_SIZE - 1) / PAGE_SIZE;
res = get_user_pages_fast(addr, n, (i->type & WRITE) != WRITE, pages);