8 files changed, 121 insertions, 13 deletions

diff --git a/drivers/infiniband/ulp/iser/iscsi_iser.c b/drivers/infiniband/ulp/iser/iscsi_iser.c
index 5a1cf2580e16..0474da173eb1 100644
--- a/drivers/infiniband/ulp/iser/iscsi_iser.c
+++ b/drivers/infiniband/ulp/iser/iscsi_iser.c
@@ -378,6 +378,7 @@ static void iscsi_iser_session_destroy(struct iscsi_cls_session *cls_session)
 {
         struct Scsi_Host *shost = iscsi_session_to_shost(cls_session);
 
+        iscsi_session_teardown(cls_session);
         iscsi_host_remove(shost);
         iscsi_host_free(shost);
 }
diff --git a/drivers/scsi/iscsi_tcp.c b/drivers/scsi/iscsi_tcp.c
index e960f00da93a..752f42884cc1 100644
--- a/drivers/scsi/iscsi_tcp.c
+++ b/drivers/scsi/iscsi_tcp.c
@@ -1885,6 +1885,7 @@ 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);
 
         iscsi_host_remove(shost);
         iscsi_host_free(shost);
diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
index f9539af28f02..390781894be9 100644
--- a/drivers/scsi/libiscsi.c
+++ b/drivers/scsi/libiscsi.c
@@ -983,6 +983,38 @@ struct iscsi_task *iscsi_itt_to_ctask(struct iscsi_conn *conn, itt_t itt)
 }
 EXPORT_SYMBOL_GPL(iscsi_itt_to_ctask);
 
+void iscsi_session_failure(struct iscsi_cls_session *cls_session,
+                           enum iscsi_err err)
+{
+        struct iscsi_session *session = cls_session->dd_data;
+        struct iscsi_conn *conn;
+        struct device *dev;
+        unsigned long flags;
+
+        spin_lock_irqsave(&session->lock, flags);
+        conn = session->leadconn;
+        if (session->state == ISCSI_STATE_TERMINATE || !conn) {
+                spin_unlock_irqrestore(&session->lock, flags);
+                return;
+        }
+
+        dev = get_device(&conn->cls_conn->dev);
+        spin_unlock_irqrestore(&session->lock, flags);
+        if (!dev)
+                return;
+        /*
+         * if the host is being removed bypass the connection
+         * recovery initialization because we are going to kill
+         * the session.
+         */
+        if (err == ISCSI_ERR_INVALID_HOST)
+                iscsi_conn_error_event(conn->cls_conn, err);
+        else
+                iscsi_conn_failure(conn, err);
+        put_device(dev);
+}
+EXPORT_SYMBOL_GPL(iscsi_session_failure);
+
 void iscsi_conn_failure(struct iscsi_conn *conn, enum iscsi_err err)
 {
         struct iscsi_session *session = conn->session;
@@ -997,9 +1029,10 @@ void iscsi_conn_failure(struct iscsi_conn *conn, enum iscsi_err err)
         if (conn->stop_stage == 0)
                 session->state = ISCSI_STATE_FAILED;
         spin_unlock_irqrestore(&session->lock, flags);
+
         set_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx);
         set_bit(ISCSI_SUSPEND_BIT, &conn->suspend_rx);
-        iscsi_conn_error(conn->cls_conn, err);
+        iscsi_conn_error_event(conn->cls_conn, err);
 }
 EXPORT_SYMBOL_GPL(iscsi_conn_failure);
 
@@ -1905,6 +1938,7 @@ struct Scsi_Host *iscsi_host_alloc(struct scsi_host_template *sht,
                                    int dd_data_size, uint16_t qdepth)
 {
         struct Scsi_Host *shost;
+        struct iscsi_host *ihost;
 
         shost = scsi_host_alloc(sht, sizeof(struct iscsi_host) + dd_data_size);
         if (!shost)
@@ -1919,22 +1953,43 @@ struct Scsi_Host *iscsi_host_alloc(struct scsi_host_template *sht,
                 qdepth = ISCSI_DEF_CMD_PER_LUN;
         }
         shost->cmd_per_lun = qdepth;
+
+        ihost = shost_priv(shost);
+        spin_lock_init(&ihost->lock);
+        ihost->state = ISCSI_HOST_SETUP;
+        ihost->num_sessions = 0;
+        init_waitqueue_head(&ihost->session_removal_wq);
         return shost;
 }
 EXPORT_SYMBOL_GPL(iscsi_host_alloc);
 
+static void iscsi_notify_host_removed(struct iscsi_cls_session *cls_session)
+{
+        iscsi_session_failure(cls_session, ISCSI_ERR_INVALID_HOST);
+}
+
 /**
  * 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.
+ * If there are any sessions left, this will initiate the removal and wait
+ * for the completion.
  */
 void iscsi_host_remove(struct Scsi_Host *shost)
 {
-        iscsi_host_for_each_session(shost, iscsi_session_teardown);
+        struct iscsi_host *ihost = shost_priv(shost);
+        unsigned long flags;
+
+        spin_lock_irqsave(&ihost->lock, flags);
+        ihost->state = ISCSI_HOST_REMOVED;
+        spin_unlock_irqrestore(&ihost->lock, flags);
+
+        iscsi_host_for_each_session(shost, iscsi_notify_host_removed);
+        wait_event_interruptible(ihost->session_removal_wq,
+                                 ihost->num_sessions == 0);
+        if (signal_pending(current))
+                flush_signals(current);
+
         scsi_remove_host(shost);
 }
 EXPORT_SYMBOL_GPL(iscsi_host_remove);
@@ -1950,6 +2005,27 @@ void iscsi_host_free(struct Scsi_Host *shost)
 }
 EXPORT_SYMBOL_GPL(iscsi_host_free);
 
+static void iscsi_host_dec_session_cnt(struct Scsi_Host *shost)
+{
+        struct iscsi_host *ihost = shost_priv(shost);
+        unsigned long flags;
+
+        shost = scsi_host_get(shost);
+        if (!shost) {
+                printk(KERN_ERR "Invalid state. Cannot notify host removal "
+                      "of session teardown event because host already "
+                      "removed.\n");
+                return;
+        }
+
+        spin_lock_irqsave(&ihost->lock, flags);
+        ihost->num_sessions--;
+        if (ihost->num_sessions == 0)
+                wake_up(&ihost->session_removal_wq);
+        spin_unlock_irqrestore(&ihost->lock, flags);
+        scsi_host_put(shost);
+}
+
 /**
  * iscsi_session_setup - create iscsi cls session and host and session
  * @iscsit: iscsi transport template
@@ -1970,9 +2046,19 @@ iscsi_session_setup(struct iscsi_transport *iscsit, struct Scsi_Host *shost,
                     uint16_t cmds_max, int cmd_task_size,
                     uint32_t initial_cmdsn, unsigned int id)
 {
+        struct iscsi_host *ihost = shost_priv(shost);
         struct iscsi_session *session;
         struct iscsi_cls_session *cls_session;
         int cmd_i, scsi_cmds, total_cmds = cmds_max;
+        unsigned long flags;
+
+        spin_lock_irqsave(&ihost->lock, flags);
+        if (ihost->state == ISCSI_HOST_REMOVED) {
+                spin_unlock_irqrestore(&ihost->lock, flags);
+                return NULL;
+        }
+        ihost->num_sessions++;
+        spin_unlock_irqrestore(&ihost->lock, flags);
 
         if (!total_cmds)
                 total_cmds = ISCSI_DEF_XMIT_CMDS_MAX;
@@ -1985,7 +2071,7 @@ iscsi_session_setup(struct iscsi_transport *iscsit, struct Scsi_Host *shost,
                 printk(KERN_ERR "iscsi: invalid can_queue of %d. can_queue "
                        "must be a power of two that is at least %d.\n",
                        total_cmds, ISCSI_TOTAL_CMDS_MIN);
-                return NULL;
+                goto dec_session_count;
         }
 
         if (total_cmds > ISCSI_TOTAL_CMDS_MAX) {
@@ -2009,7 +2095,7 @@ iscsi_session_setup(struct iscsi_transport *iscsit, struct Scsi_Host *shost,
         cls_session = iscsi_alloc_session(shost, iscsit,
                                           sizeof(struct iscsi_session));
         if (!cls_session)
-                return NULL;
+                goto dec_session_count;
         session = cls_session->dd_data;
         session->cls_session = cls_session;
         session->host = shost;
@@ -2048,6 +2134,7 @@ iscsi_session_setup(struct iscsi_transport *iscsit, struct Scsi_Host *shost,
 
         if (iscsi_add_session(cls_session, id))
                 goto cls_session_fail;
+
         return cls_session;
 
 cls_session_fail:
@@ -2056,6 +2143,8 @@ module_get_fail:
         iscsi_pool_free(&session->cmdpool);
 cmdpool_alloc_fail:
         iscsi_free_session(cls_session);
+dec_session_count:
+        iscsi_host_dec_session_cnt(shost);
         return NULL;
 }
 EXPORT_SYMBOL_GPL(iscsi_session_setup);
@@ -2071,6 +2160,7 @@ void iscsi_session_teardown(struct iscsi_cls_session *cls_session)
 {
         struct iscsi_session *session = cls_session->dd_data;
         struct module *owner = cls_session->transport->owner;
+        struct Scsi_Host *shost = session->host;
 
         iscsi_pool_free(&session->cmdpool);
 
@@ -2083,6 +2173,7 @@ void iscsi_session_teardown(struct iscsi_cls_session *cls_session)
         kfree(session->ifacename);
 
         iscsi_destroy_session(cls_session);
+        iscsi_host_dec_session_cnt(shost);
         module_put(owner);
 }
 EXPORT_SYMBOL_GPL(iscsi_session_teardown);
diff --git a/drivers/scsi/qla4xxx/ql4_os.c b/drivers/scsi/qla4xxx/ql4_os.c
index 4255b36ff968..db7ea3bb4e83 100644
--- a/drivers/scsi/qla4xxx/ql4_os.c
+++ b/drivers/scsi/qla4xxx/ql4_os.c
@@ -353,7 +353,7 @@ void qla4xxx_mark_device_missing(struct scsi_qla_host *ha,
                       ha->host_no, ddb_entry->bus, ddb_entry->target,
                       ddb_entry->fw_ddb_index));
         iscsi_block_session(ddb_entry->sess);
-        iscsi_conn_error(ddb_entry->conn, ISCSI_ERR_CONN_FAILED);
+        iscsi_conn_error_event(ddb_entry->conn, ISCSI_ERR_CONN_FAILED);
 }
 
 static struct srb* qla4xxx_get_new_srb(struct scsi_qla_host *ha,
diff --git a/drivers/scsi/scsi_transport_iscsi.c b/drivers/scsi/scsi_transport_iscsi.c
index cbaae48f47ed..f9e45f83e467 100644
--- a/drivers/scsi/scsi_transport_iscsi.c
+++ b/drivers/scsi/scsi_transport_iscsi.c
@@ -1010,7 +1010,7 @@ int iscsi_recv_pdu(struct iscsi_cls_conn *conn, struct iscsi_hdr *hdr,
 
         skb = alloc_skb(len, GFP_ATOMIC);
         if (!skb) {
-                iscsi_conn_error(conn, ISCSI_ERR_CONN_FAILED);
+                iscsi_conn_error_event(conn, ISCSI_ERR_CONN_FAILED);
                 iscsi_cls_conn_printk(KERN_ERR, conn, "can not deliver "
                                       "control PDU: OOM\n");
                 return -ENOMEM;
@@ -1031,7 +1031,7 @@ int iscsi_recv_pdu(struct iscsi_cls_conn *conn, struct iscsi_hdr *hdr,
 }
 EXPORT_SYMBOL_GPL(iscsi_recv_pdu);
 
-void iscsi_conn_error(struct iscsi_cls_conn *conn, enum iscsi_err error)
+void iscsi_conn_error_event(struct iscsi_cls_conn *conn, enum iscsi_err error)
 {
         struct nlmsghdr *nlh;
         struct sk_buff  *skb;
@@ -1063,7 +1063,7 @@ void iscsi_conn_error(struct iscsi_cls_conn *conn, enum iscsi_err error)
         iscsi_cls_conn_printk(KERN_INFO, conn, "detected conn error (%d)\n",
                               error);
 }
-EXPORT_SYMBOL_GPL(iscsi_conn_error);
+EXPORT_SYMBOL_GPL(iscsi_conn_error_event);
 
 static int
 iscsi_if_send_reply(int pid, int seq, int type, int done, int multi,
diff --git a/include/scsi/iscsi_if.h b/include/scsi/iscsi_if.h
index 16be12f1cbe8..f274d248a91f 100644
--- a/include/scsi/iscsi_if.h
+++ b/include/scsi/iscsi_if.h
@@ -213,6 +213,7 @@ enum iscsi_err {
         ISCSI_ERR_DATA_DGST             = ISCSI_ERR_BASE + 15,
         ISCSI_ERR_PARAM_NOT_FOUND       = ISCSI_ERR_BASE + 16,
         ISCSI_ERR_NO_SCSI_CMD           = ISCSI_ERR_BASE + 17,
+        ISCSI_ERR_INVALID_HOST          = ISCSI_ERR_BASE + 18,
 };
 
 /*
diff --git a/include/scsi/libiscsi.h b/include/scsi/libiscsi.h
index 5e75bb7f311c..7d8cd159f592 100644
--- a/include/scsi/libiscsi.h
+++ b/include/scsi/libiscsi.h
@@ -287,6 +287,11 @@ struct iscsi_session {
         struct iscsi_pool       cmdpool;        /* PDU's pool */
 };
 
+enum {
+        ISCSI_HOST_SETUP,
+        ISCSI_HOST_REMOVED,
+};
+
 struct iscsi_host {
         char                    *initiatorname;
         /* hw address or netdev iscsi connection is bound to */
@@ -295,6 +300,12 @@ struct iscsi_host {
         /* local address */
         int                     local_port;
         char                    local_address[ISCSI_ADDRESS_BUF_LEN];
+
+        wait_queue_head_t       session_removal_wq;
+        /* protects sessions and state */
+        spinlock_t              lock;
+        int                     num_sessions;
+        int                     state;
 };
 
 /*
@@ -351,6 +362,8 @@ extern void iscsi_conn_stop(struct iscsi_cls_conn *, int);
 extern int iscsi_conn_bind(struct iscsi_cls_session *, struct iscsi_cls_conn *,
                            int);
 extern void iscsi_conn_failure(struct iscsi_conn *conn, enum iscsi_err err);
+extern void iscsi_session_failure(struct iscsi_cls_session *cls_session,
+                                  enum iscsi_err err);
 extern int iscsi_conn_get_param(struct iscsi_cls_conn *cls_conn,
                                 enum iscsi_param param, char *buf);
 extern void iscsi_suspend_tx(struct iscsi_conn *conn);
diff --git a/include/scsi/scsi_transport_iscsi.h b/include/scsi/scsi_transport_iscsi.h
index 8b6c91df4c7a..8749d4d8e244 100644
--- a/include/scsi/scsi_transport_iscsi.h
+++ b/include/scsi/scsi_transport_iscsi.h
@@ -135,7 +135,8 @@ extern int iscsi_unregister_transport(struct iscsi_transport *tt);
 /*
  * control plane upcalls
  */
-extern void iscsi_conn_error(struct iscsi_cls_conn *conn, enum iscsi_err error);
+extern void iscsi_conn_error_event(struct iscsi_cls_conn *conn,
+                                   enum iscsi_err error);
 extern int iscsi_recv_pdu(struct iscsi_cls_conn *conn, struct iscsi_hdr *hdr,
                           char *data, uint32_t data_size);