static __wsum csum_and_memcpy(void *to, const void *from, size_t len,
			      __wsum sum, size_t off)
{
	__wsum next = csum_partial_copy_nocheck(from, to, len);
	return csum_block_add(sum, next, off);
}
static __wsum csum_and_memcpy(void *to, const void *from, size_t len,
			      __wsum sum, size_t off)
{
	__wsum next = csum_partial_copy_nocheck(from, to, len);
	return csum_block_add(sum, next, off);
}