nfsd4_encode_getdeviceinfo(struct nfsd4_compoundres *resp, __be32 nfserr,
		struct nfsd4_getdeviceinfo *gdev)
{
	struct xdr_stream *xdr = &resp->xdr;
	const struct nfsd4_layout_ops *ops =
		nfsd4_layout_ops[gdev->gd_layout_type];
	u32 starting_len = xdr->buf->len, needed_len;
	__be32 *p;

	dprintk("%s: err %d\n", __func__, be32_to_cpu(nfserr));
	if (nfserr)
		goto out;

	nfserr = nfserr_resource;
	p = xdr_reserve_space(xdr, 4);
	if (!p)
		goto out;

	*p++ = cpu_to_be32(gdev->gd_layout_type);

	/* If maxcount is 0 then just update notifications */
	if (gdev->gd_maxcount != 0) {
		nfserr = ops->encode_getdeviceinfo(xdr, gdev);
		if (nfserr) {
			/*
			 * We don't bother to burden the layout drivers with
			 * enforcing gd_maxcount, just tell the client to
			 * come back with a bigger buffer if it's not enough.
			 */
			if (xdr->buf->len + 4 > gdev->gd_maxcount)
				goto toosmall;
			goto out;
		}
	}

	nfserr = nfserr_resource;
	if (gdev->gd_notify_types) {
		p = xdr_reserve_space(xdr, 4 + 4);
		if (!p)
			goto out;
		*p++ = cpu_to_be32(1);			/* bitmap length */
		*p++ = cpu_to_be32(gdev->gd_notify_types);
	} else {
		p = xdr_reserve_space(xdr, 4);
		if (!p)
			goto out;
		*p++ = 0;
	}

	nfserr = 0;
out:
	kfree(gdev->gd_device);
	dprintk("%s: done: %d\n", __func__, be32_to_cpu(nfserr));
	return nfserr;

toosmall:
	dprintk("%s: maxcount too small\n", __func__);
	needed_len = xdr->buf->len + 4 /* notifications */;
	xdr_truncate_encode(xdr, starting_len);
	p = xdr_reserve_space(xdr, 4);
	if (!p) {
		nfserr = nfserr_resource;
	} else {
		*p++ = cpu_to_be32(needed_len);
		nfserr = nfserr_toosmall;
	}
	goto out;
}
The product uses untrusted input when calculating or using an array index, but the product does not validate or incorrectly validates the index to ensure the index references a valid position within the array.