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>
diff --git a/drivers/target/iscsi/iscsi_target_configfs.c b/drivers/target/iscsi/iscsi_target_configfs.c
index f86833f..f491f96 100644
--- a/drivers/target/iscsi/iscsi_target_configfs.c
+++ b/drivers/target/iscsi/iscsi_target_configfs.c
@@ -1034,6 +1034,9 @@
DEF_TPG_PARAM(MaxRecvDataSegmentLength);
TPG_PARAM_ATTR(MaxRecvDataSegmentLength, S_IRUGO | S_IWUSR);
+DEF_TPG_PARAM(MaxXmitDataSegmentLength);
+TPG_PARAM_ATTR(MaxXmitDataSegmentLength, S_IRUGO | S_IWUSR);
+
DEF_TPG_PARAM(MaxBurstLength);
TPG_PARAM_ATTR(MaxBurstLength, S_IRUGO | S_IWUSR);
@@ -1079,6 +1082,7 @@
&iscsi_tpg_param_InitialR2T.attr,
&iscsi_tpg_param_ImmediateData.attr,
&iscsi_tpg_param_MaxRecvDataSegmentLength.attr,
+ &iscsi_tpg_param_MaxXmitDataSegmentLength.attr,
&iscsi_tpg_param_MaxBurstLength.attr,
&iscsi_tpg_param_FirstBurstLength.attr,
&iscsi_tpg_param_DefaultTime2Wait.attr,
diff --git a/drivers/target/iscsi/iscsi_target_core.h b/drivers/target/iscsi/iscsi_target_core.h
index 8a908b2..b26611a 100644
--- a/drivers/target/iscsi/iscsi_target_core.h
+++ b/drivers/target/iscsi/iscsi_target_core.h
@@ -239,6 +239,7 @@
u8 HeaderDigest; /* [0,1] == [None,CRC32C] */
u8 DataDigest; /* [0,1] == [None,CRC32C] */
u32 MaxRecvDataSegmentLength; /* [512..2**24-1] */
+ u32 MaxXmitDataSegmentLength; /* [512..2**24-1] */
u8 OFMarker; /* [0,1] == [No,Yes] */
u8 IFMarker; /* [0,1] == [No,Yes] */
u32 OFMarkInt; /* [1..65535] */
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, ¶m_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)) {
diff --git a/drivers/target/iscsi/iscsi_target_parameters.h b/drivers/target/iscsi/iscsi_target_parameters.h
index 6a37fd6..77a28b5 100644
--- a/drivers/target/iscsi/iscsi_target_parameters.h
+++ b/drivers/target/iscsi/iscsi_target_parameters.h
@@ -70,6 +70,7 @@
#define INITIALR2T "InitialR2T"
#define IMMEDIATEDATA "ImmediateData"
#define MAXRECVDATASEGMENTLENGTH "MaxRecvDataSegmentLength"
+#define MAXXMITDATASEGMENTLENGTH "MaxXmitDataSegmentLength"
#define MAXBURSTLENGTH "MaxBurstLength"
#define FIRSTBURSTLENGTH "FirstBurstLength"
#define DEFAULTTIME2WAIT "DefaultTime2Wait"
@@ -113,6 +114,10 @@
#define INITIAL_INITIALR2T YES
#define INITIAL_IMMEDIATEDATA YES
#define INITIAL_MAXRECVDATASEGMENTLENGTH "8192"
+/*
+ * Match outgoing MXDSL default to incoming Open-iSCSI default
+ */
+#define INITIAL_MAXXMITDATASEGMENTLENGTH "262144"
#define INITIAL_MAXBURSTLENGTH "262144"
#define INITIAL_FIRSTBURSTLENGTH "65536"
#define INITIAL_DEFAULTTIME2WAIT "2"
