migrate_device_pages
migrate_device_pages(src, dst, npages);
migrate_device_pages(src_pfns, dst_pfns, npages);
void migrate_device_pages(unsigned long *src_pfns, unsigned long *dst_pfns,
migrate_device_pages(src_pfns, dst_pfns, npages);
EXPORT_SYMBOL(migrate_device_pages);
migrate_device_pages(&src_pfn, &dst_pfn, 1);