iscsit_get_pdu_holder_for_seq
pdu = iscsit_get_pdu_holder_for_seq(cmd, NULL);
pdu = iscsit_get_pdu_holder_for_seq(cmd, seq);
extern struct iscsi_pdu *iscsit_get_pdu_holder_for_seq(struct iscsit_cmd *, struct iscsi_seq *);