[SCSI] iscsi: fix up iscsi eh

The current iscsi_tcp eh is not nicely setup for dm-multipath
and performs some extra task management functions when they
are not needed.

The attached patch:

- Fixes the TMF issues. If a session is rebuilt
then we do not send aborts.

- Fixes the problem where if the host reset fired, we would
return SUCCESS even though we had not really done anything
yet. This ends up causing problem with scsi_error.c's TUR.

- If someone has turned on the userspace nop daemon code to try
and detect network problems before the scsi command timeout
we can now drop and clean up the session before the scsi command
timesout and fires the eh speeding up the time it takes for a
command to go from one patch to another. For network problems
we fail the command with DID_BUS_BUSY so if failfast is set
scsi_decide_disposition fails the command up to dm for it to
try on another path.

- And we had to add some basic iscsi session block code. Previously
if we were trying to repair a session we would retrun a MLQUEUE code
in the queuecommand. This worked but it was not the most efficient
or pretty thing to do since it would take a while to relogin
to the target. For iscsi_tcp/open-iscsi a lot of the iscsi error handler
is in userspace the block code is pretty bare. We will be
adding to that for qla4xxx.

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

1 files changed, 143 insertions, 9 deletions

diff --git a/drivers/scsi/scsi_transport_iscsi.c b/drivers/scsi/scsi_transport_iscsi.c
index 72a71ebc9d03..e2b67e34d92e 100644
--- a/drivers/scsi/scsi_transport_iscsi.c
+++ b/drivers/scsi/scsi_transport_iscsi.c
@@ -31,17 +31,17 @@
 #include <scsi/scsi_transport_iscsi.h>
 #include <scsi/iscsi_if.h>
 
-#define ISCSI_SESSION_ATTRS 10
+#define ISCSI_SESSION_ATTRS 11
 #define ISCSI_CONN_ATTRS 10
+#define ISCSI_HOST_ATTRS 0
 
 struct iscsi_internal {
         struct scsi_transport_template t;
         struct iscsi_transport *iscsi_transport;
         struct list_head list;
         struct class_device cdev;
-        /*
-         * We do not have any private or other attrs.
-         */
+
+        struct class_device_attribute *host_attrs[ISCSI_HOST_ATTRS + 1];
         struct transport_container conn_cont;
         struct class_device_attribute *conn_attrs[ISCSI_CONN_ATTRS + 1];
         struct transport_container session_cont;
@@ -114,6 +114,24 @@ static struct attribute_group iscsi_transport_group = {
         .attrs = iscsi_transport_attrs,
 };
 
+static int iscsi_setup_host(struct transport_container *tc, struct device *dev,
+                            struct class_device *cdev)
+{
+        struct Scsi_Host *shost = dev_to_shost(dev);
+        struct iscsi_host *ihost = shost->shost_data;
+
+        memset(ihost, 0, sizeof(*ihost));
+        INIT_LIST_HEAD(&ihost->sessions);
+        mutex_init(&ihost->mutex);
+        return 0;
+}
+
+static DECLARE_TRANSPORT_CLASS(iscsi_host_class,
+                               "iscsi_host",
+                               iscsi_setup_host,
+                               NULL,
+                               NULL);
+
 static DECLARE_TRANSPORT_CLASS(iscsi_session_class,
                                "iscsi_session",
                                NULL,
@@ -225,6 +243,54 @@ static int iscsi_is_session_dev(const struct device *dev)
         return dev->release == iscsi_session_release;
 }
 
+static int iscsi_user_scan(struct Scsi_Host *shost, uint channel,
+                           uint id, uint lun)
+{
+        struct iscsi_host *ihost = shost->shost_data;
+        struct iscsi_cls_session *session;
+
+        mutex_lock(&ihost->mutex);
+        list_for_each_entry(session, &ihost->sessions, host_list) {
+                if ((channel == SCAN_WILD_CARD ||
+                     channel == session->channel) &&
+                    (id == SCAN_WILD_CARD || id == session->target_id))
+                        scsi_scan_target(&session->dev, session->channel,
+                                         session->target_id, lun, 1);
+        }
+        mutex_unlock(&ihost->mutex);
+
+        return 0;
+}
+
+static void session_recovery_timedout(void *data)
+{
+        struct iscsi_cls_session *session = data;
+
+        dev_printk(KERN_INFO, &session->dev, "session recovery timed out "
+                  "after %d secs\n", session->recovery_tmo);
+
+        if (session->transport->session_recovery_timedout)
+                session->transport->session_recovery_timedout(session);
+
+        scsi_target_unblock(&session->dev);
+}
+
+void iscsi_unblock_session(struct iscsi_cls_session *session)
+{
+        if (!cancel_delayed_work(&session->recovery_work))
+                flush_scheduled_work();
+        scsi_target_unblock(&session->dev);
+}
+EXPORT_SYMBOL_GPL(iscsi_unblock_session);
+
+void iscsi_block_session(struct iscsi_cls_session *session)
+{
+        scsi_target_block(&session->dev);
+        schedule_delayed_work(&session->recovery_work,
+                             session->recovery_tmo * HZ);
+}
+EXPORT_SYMBOL_GPL(iscsi_block_session);
+
 /**
  * iscsi_create_session - create iscsi class session
  * @shost: scsi host
@@ -233,8 +299,10 @@ static int iscsi_is_session_dev(const struct device *dev)
  * This can be called from a LLD or iscsi_transport.
  **/
 struct iscsi_cls_session *
-iscsi_create_session(struct Scsi_Host *shost, struct iscsi_transport *transport)
+iscsi_create_session(struct Scsi_Host *shost,
+                     struct iscsi_transport *transport, int channel)
 {
+        struct iscsi_host *ihost;
         struct iscsi_cls_session *session;
         int err;
 
@@ -246,13 +314,22 @@ iscsi_create_session(struct Scsi_Host *shost, struct iscsi_transport *transport)
         if (!session)
                 goto module_put;
         session->transport = transport;
+        session->recovery_tmo = 120;
+        INIT_WORK(&session->recovery_work, session_recovery_timedout, session);
+        INIT_LIST_HEAD(&session->host_list);
+        INIT_LIST_HEAD(&session->sess_list);
 
         if (transport->sessiondata_size)
                 session->dd_data = &session[1];
 
         /* this is released in the dev's release function */
         scsi_host_get(shost);
+        ihost = shost->shost_data;
+
         session->sid = iscsi_session_nr++;
+        session->channel = channel;
+        session->target_id = ihost->next_target_id++;
+
         snprintf(session->dev.bus_id, BUS_ID_SIZE, "session%u",
                  session->sid);
         session->dev.parent = &shost->shost_gendev;
@@ -265,6 +342,10 @@ iscsi_create_session(struct Scsi_Host *shost, struct iscsi_transport *transport)
         }
         transport_register_device(&session->dev);
 
+        mutex_lock(&ihost->mutex);
+        list_add(&session->host_list, &ihost->sessions);
+        mutex_unlock(&ihost->mutex);
+
         return session;
 
 free_session:
@@ -285,6 +366,16 @@ EXPORT_SYMBOL_GPL(iscsi_create_session);
  **/
 int iscsi_destroy_session(struct iscsi_cls_session *session)
 {
+        struct Scsi_Host *shost = iscsi_session_to_shost(session);
+        struct iscsi_host *ihost = shost->shost_data;
+
+        if (!cancel_delayed_work(&session->recovery_work))
+                flush_scheduled_work();
+
+        mutex_lock(&ihost->mutex);
+        list_del(&session->host_list);
+        mutex_unlock(&ihost->mutex);
+
         transport_unregister_device(&session->dev);
         device_unregister(&session->dev);
         return 0;
@@ -435,7 +526,7 @@ iscsi_transport_create_session(struct scsi_transport_template *scsit,
         if (scsi_add_host(shost, NULL))
                 goto free_host;
 
-        session = iscsi_create_session(shost, transport);
+        session = iscsi_create_session(shost, transport, 0);
         if (!session)
                 goto remove_host;
 
@@ -466,12 +557,13 @@ int iscsi_transport_destroy_session(struct Scsi_Host *shost)
         struct iscsi_cls_session *session;
         unsigned long flags;
 
-        scsi_remove_host(shost);
         session = hostdata_session(shost->hostdata);
         spin_lock_irqsave(&sesslock, flags);
         list_del(&session->sess_list);
         spin_unlock_irqrestore(&sesslock, flags);
         iscsi_destroy_session(session);
+
+        scsi_remove_host(shost);
         /* ref from host alloc */
         scsi_host_put(shost);
         return 0;
@@ -594,6 +686,7 @@ iscsi_unicast_skb(struct mempool_zone *zone, struct sk_buff *skb)
         }
 
         spin_lock_irqsave(&zone->freelock, flags);
+        INIT_LIST_HEAD(skb_to_lh(skb));
         list_add(skb_to_lh(skb), &zone->freequeue);
         spin_unlock_irqrestore(&zone->freelock, flags);
 
@@ -888,6 +981,11 @@ iscsi_set_param(struct iscsi_transport *transport, struct iscsi_uevent *ev)
                 return -EINVAL;
 
         switch (ev->u.set_param.param) {
+        case ISCSI_PARAM_SESS_RECOVERY_TMO:
+                iscsi_copy_param(ev, &value, data);
+                if (value != 0)
+                        session->recovery_tmo = value;
+                break;
         case ISCSI_PARAM_TARGET_NAME:
                 /* this should not change between logins */
                 if (session->targetname)
@@ -980,7 +1078,6 @@ iscsi_if_recv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
                         ev->r.retcode = transport->start_conn(conn);
                 else
                         err = -EINVAL;
-
                 break;
         case ISCSI_UEVENT_STOP_CONN:
                 conn = iscsi_conn_lookup(ev->u.stop_conn.sid, ev->u.stop_conn.cid);
@@ -1198,6 +1295,7 @@ static ISCSI_CLASS_ATTR(priv_sess, field, S_IRUGO, show_priv_session_##field, \
                         NULL)
 iscsi_priv_session_attr(targetname, "%s");
 iscsi_priv_session_attr(tpgt, "%d");
+iscsi_priv_session_attr(recovery_tmo, "%d");
 
 #define iscsi_priv_conn_attr_show(field, format)                        \
 static ssize_t                                                          \
@@ -1289,6 +1387,24 @@ static int iscsi_conn_match(struct attribute_container *cont,
         return &priv->conn_cont.ac == cont;
 }
 
+static int iscsi_host_match(struct attribute_container *cont,
+                            struct device *dev)
+{
+        struct Scsi_Host *shost;
+        struct iscsi_internal *priv;
+
+        if (!scsi_is_host_device(dev))
+                return 0;
+
+        shost = dev_to_shost(dev);
+        if (!shost->transportt  ||
+            shost->transportt->host_attrs.ac.class != &iscsi_host_class.class)
+                return 0;
+
+        priv = to_iscsi_internal(shost->transportt);
+        return &priv->t.host_attrs.ac == cont;
+}
+
 struct scsi_transport_template *
 iscsi_register_transport(struct iscsi_transport *tt)
 {
@@ -1307,6 +1423,7 @@ iscsi_register_transport(struct iscsi_transport *tt)
                 return NULL;
         INIT_LIST_HEAD(&priv->list);
         priv->iscsi_transport = tt;
+        priv->t.user_scan = iscsi_user_scan;
 
         priv->cdev.class = &iscsi_transport_class;
         snprintf(priv->cdev.class_id, BUS_ID_SIZE, "%s", tt->name);
@@ -1318,6 +1435,14 @@ iscsi_register_transport(struct iscsi_transport *tt)
         if (err)
                 goto unregister_cdev;
 
+        /* host parameters */
+        priv->t.host_attrs.ac.attrs = &priv->host_attrs[0];
+        priv->t.host_attrs.ac.class = &iscsi_host_class.class;
+        priv->t.host_attrs.ac.match = iscsi_host_match;
+        priv->t.host_size = sizeof(struct iscsi_host);
+        priv->host_attrs[0] = NULL;
+        transport_container_register(&priv->t.host_attrs);
+
         /* connection parameters */
         priv->conn_cont.ac.attrs = &priv->conn_attrs[0];
         priv->conn_cont.ac.class = &iscsi_connection_class.class;
@@ -1361,6 +1486,7 @@ iscsi_register_transport(struct iscsi_transport *tt)
         SETUP_SESSION_RD_ATTR(data_pdu_in_order, ISCSI_PDU_INORDER_EN);
         SETUP_SESSION_RD_ATTR(data_seq_in_order, ISCSI_DATASEQ_INORDER_EN);
         SETUP_SESSION_RD_ATTR(erl, ISCSI_ERL);
+        SETUP_PRIV_SESSION_RD_ATTR(recovery_tmo);
 
         if (tt->param_mask & ISCSI_TARGET_NAME)
                 SETUP_SESSION_RD_ATTR(targetname, ISCSI_TARGET_NAME);
@@ -1408,6 +1534,7 @@ int iscsi_unregister_transport(struct iscsi_transport *tt)
 
         transport_container_unregister(&priv->conn_cont);
         transport_container_unregister(&priv->session_cont);
+        transport_container_unregister(&priv->t.host_attrs);
 
         sysfs_remove_group(&priv->cdev.kobj, &iscsi_transport_group);
         class_device_unregister(&priv->cdev);
@@ -1451,10 +1578,14 @@ static __init int iscsi_transport_init(void)
         if (err)
                 return err;
 
-        err = transport_class_register(&iscsi_connection_class);
+        err = transport_class_register(&iscsi_host_class);
         if (err)
                 goto unregister_transport_class;
 
+        err = transport_class_register(&iscsi_connection_class);
+        if (err)
+                goto unregister_host_class;
+
         err = transport_class_register(&iscsi_session_class);
         if (err)
                 goto unregister_conn_class;
@@ -1482,6 +1613,8 @@ unregister_session_class:
         transport_class_unregister(&iscsi_session_class);
 unregister_conn_class:
         transport_class_unregister(&iscsi_connection_class);
+unregister_host_class:
+        transport_class_unregister(&iscsi_host_class);
 unregister_transport_class:
         class_unregister(&iscsi_transport_class);
         return err;
@@ -1494,6 +1627,7 @@ static void __exit iscsi_transport_exit(void)
         netlink_unregister_notifier(&iscsi_nl_notifier);
         transport_class_unregister(&iscsi_connection_class);
         transport_class_unregister(&iscsi_session_class);
+        transport_class_unregister(&iscsi_host_class);
         class_unregister(&iscsi_transport_class);
 }