commit e004cb25927ad7a67c109ac13e1d2e5e378430dd
author Nicholas Bellinger <nab@linux-iscsi.org> Sat Sep 29 21:47:16 2012 -0700
committer Nicholas Bellinger <nab@linux-iscsi.org> Tue Oct 02 13:17:30 2012 -0700
tree 230c12934d68535a6725ab70617a5c7296cda258
parent b32f4c7ed85c5cee2a21a55c9f59ebc9d57a2463

iscsi-target: Add base MaxXmitDataSegmentLength code

This patch introduces a new per connection MaxXmitDataSegmentLength
parameter value used to represent the outgoing MaxRecvDataSegmentLength
that is actually sent over the wire during iSCSI login response back
to the initiator side.

It also adds a new MaxXmitDataSegmentLength configfs attribute to
represent this value within the existing TPG parameter group under
/sys/kernel/config/target/iscsi/$TARGETNAME/$TPGT/param/

Cc: Mike Christie <michaelc@cs.wisc.edu>
Cc: Andy Grover <agrover@redhat.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Roland Dreier <roland@purestorage.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

drivers/target/iscsi/iscsi_target_parameters.c

diff --git a/drivers/target/iscsi/iscsi_target_parameters.c b/drivers/target/iscsi/iscsi_target_parameters.c
index 0c4760f..40864ee 100644
--- a/drivers/target/iscsi/iscsi_target_parameters.c
+++ b/drivers/target/iscsi/iscsi_target_parameters.c
@@ -334,6 +334,13 @@
 	if (!param)
 		goto out;
 
+	param = iscsi_set_default_param(pl, MAXXMITDATASEGMENTLENGTH,
+			INITIAL_MAXXMITDATASEGMENTLENGTH,
+			PHASE_OPERATIONAL, SCOPE_CONNECTION_ONLY, SENDER_BOTH,
+			TYPERANGE_512_TO_16777215, USE_ALL);
+	if (!param)
+		goto out;
+
 	param = iscsi_set_default_param(pl, MAXRECVDATASEGMENTLENGTH,
 			INITIAL_MAXRECVDATASEGMENTLENGTH,
 			PHASE_OPERATIONAL, SCOPE_CONNECTION_ONLY, SENDER_BOTH,
@@ -467,6 +474,8 @@
 			SET_PSTATE_NEGOTIATE(param);
 		} else if (!strcmp(param->name, MAXRECVDATASEGMENTLENGTH)) {
 			SET_PSTATE_NEGOTIATE(param);
+		} else if (!strcmp(param->name, MAXXMITDATASEGMENTLENGTH)) {
+			continue;
 		} else if (!strcmp(param->name, MAXBURSTLENGTH)) {
 			SET_PSTATE_NEGOTIATE(param);
 		} else if (!strcmp(param->name, FIRSTBURSTLENGTH)) {
@@ -1720,6 +1729,18 @@
 	pr_debug("---------------------------------------------------"
 			"---------------\n");
 	list_for_each_entry(param, &param_list->param_list, p_list) {
+		/*
+		 * Special case to set MAXXMITDATASEGMENTLENGTH from the
+		 * target requested MaxRecvDataSegmentLength, even though
+		 * this key is not sent over the wire.
+		 */
+		if (!strcmp(param->name, MAXXMITDATASEGMENTLENGTH)) {
+			ops->MaxXmitDataSegmentLength =
+				simple_strtoul(param->value, &tmpptr, 0);
+			pr_debug("MaxXmitDataSegmentLength:     %s\n",
+				param->value);
+		}
+
 		if (!IS_PSTATE_ACCEPTOR(param) && !IS_PSTATE_PROPOSER(param))
 			continue;
 		if (!strcmp(param->name, AUTHMETHOD)) {