[SCSI] iscsi: add iscsi host helpers

This finishes the host/session unbinding, by adding some helpers
to add and remove hosts and the session they manage.

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

3 files changed, 80 insertions, 18 deletions

diff --git a/drivers/scsi/iscsi_tcp.c b/drivers/scsi/iscsi_tcp.c
index 8cdcaf33fb4e..e19d92f2d753 100644
--- a/drivers/scsi/iscsi_tcp.c
+++ b/drivers/scsi/iscsi_tcp.c
@@ -1866,7 +1866,7 @@ iscsi_tcp_session_create(struct Scsi_Host *shost, uint16_t cmds_max,
                 return NULL;
         }
 
-        shost = scsi_host_alloc(&iscsi_sht, sizeof(struct iscsi_host));
+        shost = iscsi_host_alloc(&iscsi_sht, 0, qdepth);
         if (!shost)
                 return NULL;
         shost->transportt = iscsi_tcp_scsi_transport;
@@ -1874,10 +1874,9 @@ iscsi_tcp_session_create(struct Scsi_Host *shost, uint16_t cmds_max,
         shost->max_id = 0;
         shost->max_channel = 0;
         shost->max_cmd_len = 16;
+        shost->can_queue = cmds_max;
 
-        iscsi_host_setup(shost, qdepth);
-
-        if (scsi_add_host(shost, NULL))
+        if (iscsi_host_add(shost, NULL))
                 goto free_host;
         *hostno = shost->host_no;
 
@@ -1912,10 +1911,9 @@ iscsi_tcp_session_create(struct Scsi_Host *shost, uint16_t cmds_max,
 remove_session:
         iscsi_session_teardown(cls_session);
 remove_host:
-        scsi_remove_host(shost);
+        iscsi_host_remove(shost);
 free_host:
-        iscsi_host_teardown(shost);
-        scsi_host_put(shost);
+        iscsi_host_free(shost);
         return NULL;
 }
 
@@ -1924,11 +1922,9 @@ static void iscsi_tcp_session_destroy(struct iscsi_cls_session *cls_session)
         struct Scsi_Host *shost = iscsi_session_to_shost(cls_session);
 
         iscsi_r2tpool_free(cls_session->dd_data);
-        iscsi_session_teardown(cls_session);
 
-        scsi_remove_host(shost);
-        iscsi_host_teardown(shost);
-        scsi_host_put(shost);
+        iscsi_host_remove(shost);
+        iscsi_host_free(shost);
 }
 
 static int iscsi_tcp_slave_configure(struct scsi_device *sdev)
diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
index 64b1dd827366..73c37c04ca66 100644
--- a/drivers/scsi/libiscsi.c
+++ b/drivers/scsi/libiscsi.c
@@ -1764,8 +1764,39 @@ void iscsi_pool_free(struct iscsi_pool *q)
 }
 EXPORT_SYMBOL_GPL(iscsi_pool_free);
 
-void iscsi_host_setup(struct Scsi_Host *shost, uint16_t qdepth)
+/**
+ * iscsi_host_add - add host to system
+ * @shost: scsi host
+ * @pdev: parent device
+ *
+ * This should be called by partial offload and software iscsi drivers
+ * to add a host to the system.
+ */
+int iscsi_host_add(struct Scsi_Host *shost, struct device *pdev)
+{
+        return scsi_add_host(shost, pdev);
+}
+EXPORT_SYMBOL_GPL(iscsi_host_add);
+
+/**
+ * iscsi_host_alloc - allocate a host and driver data
+ * @sht: scsi host template
+ * @dd_data_size: driver host data size
+ * @qdepth: default device queue depth
+ *
+ * This should be called by partial offload and software iscsi drivers.
+ * To access the driver specific memory use the iscsi_host_priv() macro.
+ */
+struct Scsi_Host *iscsi_host_alloc(struct scsi_host_template *sht,
+                                   int dd_data_size, uint16_t qdepth)
 {
+        struct Scsi_Host *shost;
+
+        shost = scsi_host_alloc(sht, sizeof(struct iscsi_host) + dd_data_size);
+        if (!shost)
+                return NULL;
+        shost->transportt->eh_timed_out = iscsi_eh_cmd_timed_out;
+
         if (qdepth > ISCSI_MAX_CMD_PER_LUN || qdepth < 1) {
                 if (qdepth != 0)
                         printk(KERN_ERR "iscsi: invalid queue depth of %d. "
@@ -1773,22 +1804,37 @@ void iscsi_host_setup(struct Scsi_Host *shost, uint16_t qdepth)
                                qdepth, ISCSI_MAX_CMD_PER_LUN);
                 qdepth = ISCSI_DEF_CMD_PER_LUN;
         }
-
-        shost->transportt->create_work_queue = 1;
-        shost->transportt->eh_timed_out = iscsi_eh_cmd_timed_out;
         shost->cmd_per_lun = qdepth;
+        return shost;
+}
+EXPORT_SYMBOL_GPL(iscsi_host_alloc);
+
+/**
+ * iscsi_host_remove - remove host and sessions
+ * @shost: scsi host
+ *
+ * This will also remove any sessions attached to the host, but if userspace
+ * is managing the session at the same time this will break. TODO: add
+ * refcounting to the netlink iscsi interface so a rmmod or host hot unplug
+ * does not remove the memory from under us.
+ */
+void iscsi_host_remove(struct Scsi_Host *shost)
+{
+        iscsi_host_for_each_session(shost, iscsi_session_teardown);
+        scsi_remove_host(shost);
 }
-EXPORT_SYMBOL_GPL(iscsi_host_setup);
+EXPORT_SYMBOL_GPL(iscsi_host_remove);
 
-void iscsi_host_teardown(struct Scsi_Host *shost)
+void iscsi_host_free(struct Scsi_Host *shost)
 {
         struct iscsi_host *ihost = shost_priv(shost);
 
         kfree(ihost->netdev);
         kfree(ihost->hwaddress);
         kfree(ihost->initiatorname);
+        scsi_host_put(shost);
 }
-EXPORT_SYMBOL_GPL(iscsi_host_teardown);
+EXPORT_SYMBOL_GPL(iscsi_host_free);
 
 /**
  * iscsi_session_setup - create iscsi cls session and host and session
diff --git a/drivers/scsi/scsi_transport_iscsi.c b/drivers/scsi/scsi_transport_iscsi.c
index 9c00a157b485..6fdaa2ee6632 100644
--- a/drivers/scsi/scsi_transport_iscsi.c
+++ b/drivers/scsi/scsi_transport_iscsi.c
@@ -279,6 +279,24 @@ static int iscsi_is_session_dev(const struct device *dev)
         return dev->release == iscsi_session_release;
 }
 
+static int iscsi_iter_session_fn(struct device *dev, void *data)
+{
+        void (* fn) (struct iscsi_cls_session *) = data;
+
+        if (!iscsi_is_session_dev(dev))
+                return 0;
+        fn(iscsi_dev_to_session(dev));
+        return 0;
+}
+
+void iscsi_host_for_each_session(struct Scsi_Host *shost,
+                                 void (*fn)(struct iscsi_cls_session *))
+{
+        device_for_each_child(&shost->shost_gendev, fn,
+                              iscsi_iter_session_fn);
+}
+EXPORT_SYMBOL_GPL(iscsi_host_for_each_session);
+
 /**
  * iscsi_scan_finished - helper to report when running scans are done
  * @shost: scsi host
@@ -1599,6 +1617,8 @@ iscsi_register_transport(struct iscsi_transport *tt)
         priv->daemon_pid = -1;
         priv->iscsi_transport = tt;
         priv->t.user_scan = iscsi_user_scan;
+        if (!(tt->caps & CAP_DATA_PATH_OFFLOAD))
+                priv->t.create_work_queue = 1;
 
         priv->dev.class = &iscsi_transport_class;
         snprintf(priv->dev.bus_id, BUS_ID_SIZE, "%s", tt->name);