Introduce ocf_forward_get_data()

Skip the ocf_io abstraction and get the data directly from the request.

Signed-off-by: Robert Baldyga <robert.baldyga@huawei.com>
Signed-off-by: Michal Mielewczyk <michal.mielewczyk@huawei.com>

inc/ocf_io.h

@@ -243,6 +243,13 @@ ocf_volume_t ocf_io_get_volume(struct ocf_io *io);
  */
 struct ocf_io *ocf_forward_get_io(ocf_forward_token_t token);
 
+/**
+ * @brief Get the data to be submitted
+ *
+ * @param[in] token Forward token
+ */
+ctx_data_t *ocf_forward_get_data(ocf_forward_token_t token);
+
 /**
  * @brief Forward io to another subvolume
  *