iser-target: Add support for ISCSI_OP_TEXT opcode + payload handling
This patch adds isert_handle_text_cmd() to handle incoming
ISCSI_OP_TEXT PDU processing, along with isert_put_text_rsp()
for posting ISCSI_OP_TEXT_RSP ib_send_wr response.
It copies ISCSI_OP_TEXT payload using unsolicited payload at
&iser_rx_desc->data[0] into iscsi_cmd->text_in_ptr for usage
with outgoing isert_put_text_rsp() -> iscsit_build_text_rsp()
v2 changes:
- Let iscsit_build_text_rsp() determine any extra padding
Reported-by: Or Gerlitz <ogerlitz@mellanox.com> Cc: Or Gerlitz <ogerlitz@mellanox.com> Cc: Mike Christie <michaelc@cs.wisc.edu> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>