[SCSI] iscsi: increment expstatsn during login

debugged by Ming and Rohan:

The problem Ming and Rohan debugged was that during a normal session
login, open-iscsi is not incrementing the exp_statsn counter. It was
stuck at zero. From the RFC, it looks like if the login response PDU has
a successful status then we should be incrementing that value. Also from
the RFC, it looks like if when we drop a connection then reconnect, we
should be using the exp_statsn from the old connection in the next
relogin attempt.

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
diff --git a/drivers/scsi/scsi_transport_iscsi.c b/drivers/scsi/scsi_transport_iscsi.c
index 1b96f7c..44adafa 100644
--- a/drivers/scsi/scsi_transport_iscsi.c
+++ b/drivers/scsi/scsi_transport_iscsi.c
@@ -32,7 +32,7 @@
 #include <scsi/iscsi_if.h>
 
 #define ISCSI_SESSION_ATTRS 11
-#define ISCSI_CONN_ATTRS 10
+#define ISCSI_CONN_ATTRS 11
 #define ISCSI_HOST_ATTRS 0
 
 struct iscsi_internal {
@@ -1156,6 +1156,7 @@
 iscsi_conn_int_attr(ofmarker, ISCSI_PARAM_OFMARKER_EN, "%d");
 iscsi_conn_int_attr(persistent_port, ISCSI_PARAM_PERSISTENT_PORT, "%d");
 iscsi_conn_int_attr(port, ISCSI_PARAM_CONN_PORT, "%d");
+iscsi_conn_int_attr(exp_statsn, ISCSI_PARAM_EXP_STATSN, "%u");
 
 #define iscsi_conn_str_attr_show(param)					\
 static ssize_t								\
@@ -1406,6 +1407,7 @@
 	SETUP_CONN_RD_ATTR(ofmarker, ISCSI_OFMARKER_EN);
 	SETUP_CONN_RD_ATTR(address, ISCSI_CONN_ADDRESS);
 	SETUP_CONN_RD_ATTR(port, ISCSI_CONN_PORT);
+	SETUP_CONN_RD_ATTR(exp_statsn, ISCSI_EXP_STATSN);
 
 	if (tt->param_mask & ISCSI_PERSISTENT_ADDRESS)
 		SETUP_CONN_RD_ATTR(persistent_address, ISCSI_PERSISTENT_ADDRESS);