Allow to use iSCSI immediate data by several ctl_datamove() calls.

While for FreeBSD client that is only a minor optimization, VMWare client
doesn't support additional data requests after all data being sent once as
immediate.

MFC after:	1 week
Sponsored by:	iXsystems, Inc.

1 files changed, 9 insertions, 10 deletions

diff --git a/sys/cam/ctl/ctl_frontend_iscsi.c b/sys/cam/ctl/ctl_frontend_iscsi.c
index 4aa3b5d..72f4765 100644
--- a/sys/cam/ctl/ctl_frontend_iscsi.c
+++ b/sys/cam/ctl/ctl_frontend_iscsi.c
@@ -737,12 +737,15 @@ cfiscsi_handle_data_segment(struct icl_pdu *request, struct cfiscsi_data_wait *c
 		buffer_offset = ntohl(bhsdo->bhsdo_buffer_offset);
 	else
 		buffer_offset = 0;
+	len = icl_pdu_data_segment_length(request);
 
 	/*
 	 * Make sure the offset, as sent by the initiator, matches the offset
 	 * we're supposed to be at in the scatter-gather list.
 	 */
-	if (buffer_offset !=
+	if (buffer_offset >
+	    io->scsiio.kern_rel_offset + io->scsiio.ext_data_filled ||
+	    buffer_offset + len <=
 	    io->scsiio.kern_rel_offset + io->scsiio.ext_data_filled) {
 		CFISCSI_SESSION_WARN(cs, "received bad buffer offset %zd, "
 		    "expected %zd; dropping connection", buffer_offset,
@@ -758,8 +761,8 @@ cfiscsi_handle_data_segment(struct icl_pdu *request, struct cfiscsi_data_wait *c
 	 * to buffer_offset, which is the offset within the task (SCSI
 	 * command).
 	 */
-	off = 0;
-	len = icl_pdu_data_segment_length(request);
+	off = io->scsiio.kern_rel_offset + io->scsiio.ext_data_filled -
+	    buffer_offset;
 
 	/*
 	 * Iterate over the scatter/gather segments, filling them with data
@@ -816,12 +819,8 @@ cfiscsi_handle_data_segment(struct icl_pdu *request, struct cfiscsi_data_wait *c
 		 * This obviously can only happen with SCSI Command PDU. 
 		 */
 		if ((request->ip_bhs->bhs_opcode & ~ISCSI_BHS_OPCODE_IMMEDIATE) ==
-		    ISCSI_BHS_OPCODE_SCSI_COMMAND) {
-			CFISCSI_SESSION_DEBUG(cs, "received too much immediate "
-			    "data: got %zd bytes, expected %zd",
-			    icl_pdu_data_segment_length(request), off);
+		    ISCSI_BHS_OPCODE_SCSI_COMMAND)
 			return (true);
-		}
 
 		CFISCSI_SESSION_WARN(cs, "received too much data: got %zd bytes, "
 		    "expected %zd; dropping connection",
@@ -2708,8 +2707,8 @@ cfiscsi_datamove_out(union ctl_io *io)
 	cdw->cdw_target_transfer_tag = target_transfer_tag;
 	cdw->cdw_initiator_task_tag = bhssc->bhssc_initiator_task_tag;
 
-	if (cs->cs_immediate_data && io->scsiio.kern_rel_offset == 0 &&
-	    icl_pdu_data_segment_length(request) > 0) {
+	if (cs->cs_immediate_data && io->scsiio.kern_rel_offset <
+	    icl_pdu_data_segment_length(request)) {
 		done = cfiscsi_handle_data_segment(request, cdw);
 		if (done) {
 			uma_zfree(cfiscsi_data_wait_zone, cdw);