[SCSI] libiscsi,iser: patch for AHS support

- The default initialization of hdr_max is the minimum -
    sizeof(struct iscsi_cmd) - Once this patch goes into iser the default
    initialization at libiscsi can be removed.
  - This is not yet full support for AHSs at iser end. But it should be easy.
    Just allocate more space at iser_desc right after iscsi_hdr. Than
    at transmission time use ctask->hdr_len to retrieve the total
    size of all iscsi pdu headers. See previous patch at iscsi_tcp.[ch]

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

drivers/infiniband/ulp/iser/iscsi_iser.c

@@ -400,6 +400,7 @@ iscsi_iser_session_create(struct iscsi_transport *iscsit,
 		ctask      = session->cmds[i];
 		iser_ctask = ctask->dd_data;
 		ctask->hdr = (struct iscsi_cmd *)&iser_ctask->desc.iscsi_header;
+		ctask->hdr_max = sizeof(iser_ctask->desc.iscsi_header);
 	}
 
 	for (i = 0; i < session->mgmtpool_max; i++) {

drivers/scsi/libiscsi.c

@@ -1570,7 +1570,6 @@ iscsi_session_setup(struct iscsi_transport *iscsit,
 		if (cmd_task_size)
 			ctask->dd_data = &ctask[1];
 		ctask->itt = cmd_i;
-		ctask->hdr_max = sizeof(struct iscsi_cmd);
 		INIT_LIST_HEAD(&ctask->running);
 	}