2 files changed, 50 insertions, 28 deletions

diff --git a/drivers/scsi/scsi_transport_iscsi.c b/drivers/scsi/scsi_transport_iscsi.c
index dfb026b95a6a..ca7bb6f63bde 100644
--- a/drivers/scsi/scsi_transport_iscsi.c
+++ b/drivers/scsi/scsi_transport_iscsi.c
@@ -373,24 +373,25 @@ static void session_recovery_timedout(struct work_struct *work)
         scsi_target_unblock(&session->dev);
 }
 
-static void __iscsi_unblock_session(struct iscsi_cls_session *session)
-{
-        if (!cancel_delayed_work(&session->recovery_work))
-                flush_workqueue(iscsi_eh_timer_workq);
-        scsi_target_unblock(&session->dev);
-}
-
-void iscsi_unblock_session(struct iscsi_cls_session *session)
+static void __iscsi_unblock_session(struct work_struct *work)
 {
+        struct iscsi_cls_session *session =
+                        container_of(work, struct iscsi_cls_session,
+                                     unblock_work);
         struct Scsi_Host *shost = iscsi_session_to_shost(session);
         struct iscsi_host *ihost = shost->shost_data;
         unsigned long flags;
 
+        /*
+         * The recovery and unblock work get run from the same workqueue,
+         * so try to cancel it if it was going to run after this unblock.
+         */
+        cancel_delayed_work(&session->recovery_work);
         spin_lock_irqsave(&session->lock, flags);
         session->state = ISCSI_SESSION_LOGGED_IN;
         spin_unlock_irqrestore(&session->lock, flags);
-
-        __iscsi_unblock_session(session);
+        /* start IO */
+        scsi_target_unblock(&session->dev);
         /*
          * Only do kernel scanning if the driver is properly hooked into
          * the async scanning code (drivers like iscsi_tcp do login and
@@ -401,20 +402,43 @@ void iscsi_unblock_session(struct iscsi_cls_session *session)
                         atomic_inc(&ihost->nr_scans);
         }
 }
+
+/**
+ * iscsi_unblock_session - set a session as logged in and start IO.
+ * @session: iscsi session
+ *
+ * Mark a session as ready to accept IO.
+ */
+void iscsi_unblock_session(struct iscsi_cls_session *session)
+{
+        queue_work(iscsi_eh_timer_workq, &session->unblock_work);
+        /*
+         * make sure all the events have completed before tell the driver
+         * it is safe
+         */
+        flush_workqueue(iscsi_eh_timer_workq);
+}
 EXPORT_SYMBOL_GPL(iscsi_unblock_session);
 
-void iscsi_block_session(struct iscsi_cls_session *session)
+static void __iscsi_block_session(struct work_struct *work)
 {
+        struct iscsi_cls_session *session =
+                        container_of(work, struct iscsi_cls_session,
+                                     block_work);
         unsigned long flags;
 
         spin_lock_irqsave(&session->lock, flags);
         session->state = ISCSI_SESSION_FAILED;
         spin_unlock_irqrestore(&session->lock, flags);
-
         scsi_target_block(&session->dev);
         queue_delayed_work(iscsi_eh_timer_workq, &session->recovery_work,
                            session->recovery_tmo * HZ);
 }
+
+void iscsi_block_session(struct iscsi_cls_session *session)
+{
+        queue_work(iscsi_eh_timer_workq, &session->block_work);
+}
 EXPORT_SYMBOL_GPL(iscsi_block_session);
 
 static void __iscsi_unbind_session(struct work_struct *work)
@@ -463,6 +487,8 @@ iscsi_alloc_session(struct Scsi_Host *shost,
         INIT_DELAYED_WORK(&session->recovery_work, session_recovery_timedout);
         INIT_LIST_HEAD(&session->host_list);
         INIT_LIST_HEAD(&session->sess_list);
+        INIT_WORK(&session->unblock_work, __iscsi_unblock_session);
+        INIT_WORK(&session->block_work, __iscsi_block_session);
         INIT_WORK(&session->unbind_work, __iscsi_unbind_session);
         INIT_WORK(&session->scan_work, iscsi_scan_session);
         spin_lock_init(&session->lock);
@@ -575,24 +601,25 @@ void iscsi_remove_session(struct iscsi_cls_session *session)
         list_del(&session->sess_list);
         spin_unlock_irqrestore(&sesslock, flags);
 
+        /* make sure there are no blocks/unblocks queued */
+        flush_workqueue(iscsi_eh_timer_workq);
+        /* make sure the timedout callout is not running */
+        if (!cancel_delayed_work(&session->recovery_work))
+                flush_workqueue(iscsi_eh_timer_workq);
         /*
          * If we are blocked let commands flow again. The lld or iscsi
          * layer should set up the queuecommand to fail commands.
+         * We assume that LLD will not be calling block/unblock while
+         * removing the session.
          */
         spin_lock_irqsave(&session->lock, flags);
         session->state = ISCSI_SESSION_FREE;
         spin_unlock_irqrestore(&session->lock, flags);
-        __iscsi_unblock_session(session);
-        __iscsi_unbind_session(&session->unbind_work);
 
-        /* flush running scans */
+        scsi_target_unblock(&session->dev);
+        /* flush running scans then delete devices */
         flush_workqueue(ihost->scan_workq);
-        /*
-         * If the session dropped while removing devices then we need to make
-         * sure it is not blocked
-         */
-        if (!cancel_delayed_work(&session->recovery_work))
-                flush_workqueue(iscsi_eh_timer_workq);
+        __iscsi_unbind_session(&session->unbind_work);
 
         /* hw iscsi may not have removed all connections from session */
         err = device_for_each_child(&session->dev, NULL,
@@ -802,23 +829,16 @@ EXPORT_SYMBOL_GPL(iscsi_recv_pdu);
 
 void iscsi_conn_error(struct iscsi_cls_conn *conn, enum iscsi_err error)
 {
-        struct iscsi_cls_session *session = iscsi_conn_to_session(conn);
         struct nlmsghdr *nlh;
         struct sk_buff  *skb;
         struct iscsi_uevent *ev;
         struct iscsi_internal *priv;
         int len = NLMSG_SPACE(sizeof(*ev));
-        unsigned long flags;
 
         priv = iscsi_if_transport_lookup(conn->transport);
         if (!priv)
                 return;
 
-        spin_lock_irqsave(&session->lock, flags);
-        if (session->state == ISCSI_SESSION_LOGGED_IN)
-                session->state = ISCSI_SESSION_FAILED;
-        spin_unlock_irqrestore(&session->lock, flags);
-
         skb = alloc_skb(len, GFP_ATOMIC);
         if (!skb) {
                 iscsi_cls_conn_printk(KERN_ERR, conn, "gracefully ignored "
diff --git a/include/scsi/scsi_transport_iscsi.h b/include/scsi/scsi_transport_iscsi.h
index dbc96ef4cc72..aab1eae2ec4c 100644
--- a/include/scsi/scsi_transport_iscsi.h
+++ b/include/scsi/scsi_transport_iscsi.h
@@ -177,6 +177,8 @@ struct iscsi_cls_session {
         struct list_head host_list;
         struct iscsi_transport *transport;
         spinlock_t lock;
+        struct work_struct block_work;
+        struct work_struct unblock_work;
         struct work_struct scan_work;
         struct work_struct unbind_work;