Function prepare_write_back_data

dpdk/lib/vhost/vhost_crypto.c:664–775

 *   The pointer to the start of the write back data linked list.
 */
static __rte_always_inline struct vhost_crypto_writeback_data *
prepare_write_back_data(struct vhost_crypto_data_req *vc_req,
		struct vhost_crypto_desc *head_desc,
		struct vhost_crypto_desc **cur_desc,
		struct vhost_crypto_writeback_data **end_wb_data,
		uint8_t *src,
		uint32_t offset,
		uint64_t write_back_len,
		uint32_t max_n_descs)
	__rte_shared_locks_required(&vc_req->vq->iotlb_lock)
{
	struct vhost_crypto_writeback_data *wb_data, *head;
	struct vhost_crypto_desc *desc = *cur_desc;
	uint64_t dlen;
	uint8_t *dst;
	int ret;

	ret = rte_mempool_get(vc_req->wb_pool, (void **)&head);
	if (unlikely(ret < 0)) {
		VC_LOG_ERR("no memory");
		goto error_exit;
	}

	wb_data = head;

	if (likely(desc->len > offset)) {
		wb_data->src = src + offset;
		dlen = desc->len;
		dst = IOVA_TO_VVA(uint8_t *, vc_req, desc->addr,
			&dlen, VHOST_ACCESS_RW);
		if (unlikely(!dst || dlen != desc->len)) {
			VC_LOG_ERR("Failed to map descriptor");
			goto error_exit;
		}

		wb_data->dst = dst + offset;
		wb_data->len = RTE_MIN(dlen - offset, write_back_len);
		write_back_len -= wb_data->len;
		src += offset + wb_data->len;
		offset = 0;

		if (unlikely(write_back_len)) {
			ret = rte_mempool_get(vc_req->wb_pool,
					(void **)&(wb_data->next));
			if (unlikely(ret < 0)) {
				VC_LOG_ERR("no memory");
				goto error_exit;
			}

			wb_data = wb_data->next;
		} else
			wb_data->next = NULL;
	} else
		offset -= desc->len;

	while (write_back_len &&
			desc >= head_desc &&
			desc - head_desc < (int)max_n_descs) {