[SCSI] libiscsi: prepare libiscsi for new offload engines by modifying unsol data code

cxgb3i offloads data transfers. It does not offload the entire scsi/iscsi
procssing like qla4xxx and it does not offload the iscsi sequence
processing like how bnx2i does. cxgb3i relies on iscsi_tcp for the
seqeunce handling so this changes how we transfer unsolicitied data by
adding a common r2t struct and helpers.

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
diff --git a/include/scsi/scsi_transport_iscsi.h b/include/scsi/scsi_transport_iscsi.h
index c667cc3..c928234 100644
--- a/include/scsi/scsi_transport_iscsi.h
+++ b/include/scsi/scsi_transport_iscsi.h
@@ -113,10 +113,15 @@
 			 char *data, uint32_t data_size);
 	void (*get_stats) (struct iscsi_cls_conn *conn,
 			   struct iscsi_stats *stats);
+
 	int (*init_task) (struct iscsi_task *task);
 	int (*xmit_task) (struct iscsi_task *task);
-	void (*cleanup_task) (struct iscsi_conn *conn,
-				  struct iscsi_task *task);
+	void (*cleanup_task) (struct iscsi_task *task);
+
+	int (*alloc_pdu) (struct iscsi_task *task);
+	int (*xmit_pdu) (struct iscsi_task *task);
+	int (*init_pdu) (struct iscsi_task *task, unsigned int offset,
+			 unsigned int count);
 	void (*session_recovery_timedout) (struct iscsi_cls_session *session);
 	struct iscsi_endpoint *(*ep_connect) (struct sockaddr *dst_addr,
 					      int non_blocking);