SUNRPC: When expanding the buffer, we may need grow the sparse pages

	} while ((len -= zero) != 0);

}

static unsigned int xdr_buf_pages_fill_sparse(const struct xdr_buf *buf,

					      unsigned int buflen, gfp_t gfp)

{

	unsigned int i, npages, pagelen;

	if (!(buf->flags & XDRBUF_SPARSE_PAGES))

		return buflen;

	if (buflen <= buf->head->iov_len)

		return buflen;

	pagelen = buflen - buf->head->iov_len;

	if (pagelen > buf->page_len)

		pagelen = buf->page_len;

	npages = (pagelen + buf->page_base + PAGE_SIZE - 1) >> PAGE_SHIFT;

	for (i = 0; i < npages; i++) {

		if (!buf->pages[i])

			continue;

		buf->pages[i] = alloc_page(gfp);

		if (likely(buf->pages[i]))

			continue;

		buflen -= pagelen;

		pagelen = i << PAGE_SHIFT;

		if (pagelen > buf->page_base)

			buflen += pagelen - buf->page_base;

		break;

	}

	return buflen;

}

static void xdr_buf_try_expand(struct xdr_buf *buf, unsigned int len)

{

	struct kvec *head = buf->head;

	struct kvec *tail = buf->tail;

	unsigned int sum = head->iov_len + buf->page_len + tail->iov_len;

	unsigned int free_space;

	unsigned int free_space, newlen;

	if (sum > buf->len) {

		free_space = min_t(unsigned int, sum - buf->len, len);

		buf->len += free_space;

		newlen = xdr_buf_pages_fill_sparse(buf, buf->len + free_space,

						   GFP_KERNEL);

		free_space = newlen - buf->len;

		buf->len = newlen;

		len -= free_space;

		if (!len)

			return;