[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>

4 files changed, 32 insertions, 21 deletions

diff --git a/drivers/scsi/iscsi_tcp.c b/drivers/scsi/iscsi_tcp.c
index 41f4bb557ea6..c0ce6ab81a9d 100644
--- a/drivers/scsi/iscsi_tcp.c
+++ b/drivers/scsi/iscsi_tcp.c
@@ -2298,6 +2298,9 @@ iscsi_conn_set_param(struct iscsi_cls_conn *cls_conn, enum iscsi_param param,
                 BUG_ON(value);
                 session->ofmarker_en = value;
                 break;
+        case ISCSI_PARAM_EXP_STATSN:
+                conn->exp_statsn = value;
+                break;
         default:
                 break;
         }
@@ -2381,6 +2384,9 @@ iscsi_conn_get_param(struct iscsi_cls_conn *cls_conn,
                 inet = inet_sk(tcp_conn->sock->sk);
                 *value = be16_to_cpu(inet->dport);
                 mutex_unlock(&conn->xmitmutex);
+        case ISCSI_PARAM_EXP_STATSN:
+                *value = conn->exp_statsn;
+                break;
         default:
                 return -EINVAL;
         }
@@ -2548,7 +2554,8 @@ static struct iscsi_transport iscsi_tcp_transport = {
                                   ISCSI_DATASEQ_INORDER_EN |
                                   ISCSI_ERL |
                                   ISCSI_CONN_PORT |
-                                  ISCSI_CONN_ADDRESS,
+                                  ISCSI_CONN_ADDRESS |
+                                  ISCSI_EXP_STATSN,
         .host_template          = &iscsi_sht,
         .conndata_size          = sizeof(struct iscsi_conn),
         .max_conn               = 1,
diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
index a99f2ef44e87..4750d4888100 100644
--- a/drivers/scsi/libiscsi.c
+++ b/drivers/scsi/libiscsi.c
@@ -333,15 +333,21 @@ int __iscsi_complete_pdu(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
                 debug_scsi("immrsp [op 0x%x cid %d itt 0x%x len %d]\n",
                            opcode, conn->id, mtask->itt, datalen);
 
+                rc = iscsi_check_assign_cmdsn(session,
+                                              (struct iscsi_nopin*)hdr);
+                if (rc)
+                        goto done;
+
                 switch(opcode) {
+                case ISCSI_OP_LOGOUT_RSP:
+                        conn->exp_statsn = be32_to_cpu(hdr->statsn) + 1;
+                        /* fall through */
                 case ISCSI_OP_LOGIN_RSP:
                 case ISCSI_OP_TEXT_RSP:
-                case ISCSI_OP_LOGOUT_RSP:
-                        rc = iscsi_check_assign_cmdsn(session,
-                                                 (struct iscsi_nopin*)hdr);
-                        if (rc)
-                                break;
-
+                        /*
+                         * login related PDU's exp_statsn is handled in
+                         * userspace
+                         */
                         rc = iscsi_recv_pdu(conn->cls_conn, hdr, data, datalen);
                         list_del(&mtask->running);
                         if (conn->login_mtask != mtask)
@@ -349,15 +355,12 @@ int __iscsi_complete_pdu(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
                                             (void*)&mtask, sizeof(void*));
                         break;
                 case ISCSI_OP_SCSI_TMFUNC_RSP:
-                        rc = iscsi_check_assign_cmdsn(session,
-                                                 (struct iscsi_nopin*)hdr);
-                        if (rc)
-                                break;
-
                         if (datalen) {
                                 rc = ISCSI_ERR_PROTO;
                                 break;
                         }
+
+                        conn->exp_statsn = be32_to_cpu(hdr->statsn) + 1;
                         conn->tmfrsp_pdus_cnt++;
                         if (conn->tmabort_state == TMABORT_INITIAL) {
                                 conn->tmabort_state =
@@ -373,10 +376,6 @@ int __iscsi_complete_pdu(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
                                 rc = ISCSI_ERR_PROTO;
                                 break;
                         }
-                        rc = iscsi_check_assign_cmdsn(session,
-                                                (struct iscsi_nopin*)hdr);
-                        if (rc)
-                                break;
                         conn->exp_statsn = be32_to_cpu(hdr->statsn) + 1;
 
                         rc = iscsi_recv_pdu(conn->cls_conn, hdr, data, datalen);
@@ -404,6 +403,7 @@ int __iscsi_complete_pdu(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
                 case ISCSI_OP_REJECT:
                         /* we need sth like iscsi_reject_rsp()*/
                 case ISCSI_OP_ASYNC_EVENT:
+                        conn->exp_statsn = be32_to_cpu(hdr->statsn) + 1;
                         /* we need sth like iscsi_async_event_rsp() */
                         rc = ISCSI_ERR_BAD_OPCODE;
                         break;
@@ -414,6 +414,7 @@ int __iscsi_complete_pdu(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
         } else
                 rc = ISCSI_ERR_BAD_ITT;
 
+done:
         return rc;
 }
 EXPORT_SYMBOL_GPL(__iscsi_complete_pdu);
@@ -730,6 +731,7 @@ iscsi_conn_send_generic(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
                 BUG_ON(conn->c_stage == ISCSI_CONN_INITIAL_STAGE);
                 BUG_ON(conn->c_stage == ISCSI_CONN_STOPPED);
 
+                nop->exp_statsn = cpu_to_be32(conn->exp_statsn);
                 if (!__kfifo_get(session->mgmtpool.queue,
                                  (void*)&mtask, sizeof(void*))) {
                         spin_unlock_bh(&session->lock);
@@ -738,7 +740,7 @@ iscsi_conn_send_generic(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
         }
 
         /*
-         * pre-format CmdSN and ExpStatSN for outgoing PDU.
+         * pre-format CmdSN for outgoing PDU.
          */
         if (hdr->itt != cpu_to_be32(ISCSI_RESERVED_TAG)) {
                 hdr->itt = mtask->itt | (conn->id << ISCSI_CID_SHIFT) |
@@ -751,8 +753,6 @@ iscsi_conn_send_generic(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
                 /* do not advance CmdSN */
                 nop->cmdsn = cpu_to_be32(session->cmdsn);
 
-        nop->exp_statsn = cpu_to_be32(conn->exp_statsn);
-
         if (data_size) {
                 memcpy(mtask->data, data, data_size);
                 mtask->data_count = data_size;
@@ -1647,7 +1647,7 @@ void iscsi_conn_stop(struct iscsi_cls_conn *cls_conn, int flag)
         case STOP_CONN_RECOVER:
         case STOP_CONN_TERM:
                 iscsi_start_session_recovery(session, conn, flag);
-                return;
+                break;
         case STOP_CONN_SUSPEND:
                 if (session->tt->suspend_conn_recv)
                         session->tt->suspend_conn_recv(conn);
diff --git a/drivers/scsi/scsi_transport_iscsi.c b/drivers/scsi/scsi_transport_iscsi.c
index 1b96f7c4ce7a..44adafac861f 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(ifmarker, ISCSI_PARAM_IFMARKER_EN, "%d");
 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 @@ iscsi_register_transport(struct iscsi_transport *tt)
         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);
diff --git a/include/scsi/iscsi_if.h b/include/scsi/iscsi_if.h
index feff74e544b7..253797c60095 100644
--- a/include/scsi/iscsi_if.h
+++ b/include/scsi/iscsi_if.h
@@ -188,6 +188,7 @@ enum iscsi_param {
         ISCSI_PARAM_ERL,
         ISCSI_PARAM_IFMARKER_EN,
         ISCSI_PARAM_OFMARKER_EN,
+        ISCSI_PARAM_EXP_STATSN,
         ISCSI_PARAM_TARGET_NAME,
         ISCSI_PARAM_TPGT,
         ISCSI_PARAM_PERSISTENT_ADDRESS,
@@ -216,6 +217,7 @@ enum iscsi_param {
 #define ISCSI_ERL                       (1 << ISCSI_PARAM_ERL)
 #define ISCSI_IFMARKER_EN               (1 << ISCSI_PARAM_IFMARKER_EN)
 #define ISCSI_OFMARKER_EN               (1 << ISCSI_PARAM_OFMARKER_EN)
+#define ISCSI_EXP_STATSN                (1 << ISCSI_PARAM_EXP_STATSN)
 #define ISCSI_TARGET_NAME               (1 << ISCSI_PARAM_TARGET_NAME)
 #define ISCSI_TPGT                      (1 << ISCSI_PARAM_TPGT)
 #define ISCSI_PERSISTENT_ADDRESS        (1 << ISCSI_PARAM_PERSISTENT_ADDRESS)