if (a->d) {
		p = kmalloc(nlimbs * sizeof(mpi_limb_t), GFP_KERNEL);
		if (!p)
			return -ENOMEM;
		memcpy(p, a->d, a->alloced * sizeof(mpi_limb_t));
		kzfree(a->d);
		a->d = p;
	} else {
		a->d = kzalloc(nlimbs * sizeof(mpi_limb_t), GFP_KERNEL);
		if (!a->d)
			return -ENOMEM;
	}
	a->alloced = nlimbs;
	return 0;
}