6 files changed, 66 insertions, 38 deletions

diff --git a/drivers/infiniband/ulp/ipoib/ipoib.h b/drivers/infiniband/ulp/ipoib/ipoib.h
index d7562beb5423..e940cd9f8471 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib.h
+++ b/drivers/infiniband/ulp/ipoib/ipoib.h
@@ -317,6 +317,7 @@ struct ipoib_dev_priv {
 	struct list_head multicast_list;
 	struct rb_root multicast_tree;
 
+	struct workqueue_struct *wq;
 	struct delayed_work mcast_task;
 	struct work_struct carrier_on_task;
 	struct work_struct flush_light;
diff --git a/drivers/infiniband/ulp/ipoib/ipoib_cm.c b/drivers/infiniband/ulp/ipoib/ipoib_cm.c
index 933efcea0d03..56959adb6c7d 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_cm.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_cm.c
@@ -474,7 +474,7 @@ static int ipoib_cm_req_handler(struct ib_cm_id *cm_id, struct ib_cm_event *even
 	}
 
 	spin_lock_irq(&priv->lock);
-	queue_delayed_work(ipoib_workqueue,
+	queue_delayed_work(priv->wq,
 			   &priv->cm.stale_task, IPOIB_CM_RX_DELAY);
 	/* Add this entry to passive ids list head, but do not re-add it
 	 * if IB_EVENT_QP_LAST_WQE_REACHED has moved it to flush list. */
@@ -576,7 +576,7 @@ void ipoib_cm_handle_rx_wc(struct net_device *dev, struct ib_wc *wc)
 			spin_lock_irqsave(&priv->lock, flags);
 			list_splice_init(&priv->cm.rx_drain_list, &priv->cm.rx_reap_list);
 			ipoib_cm_start_rx_drain(priv);
-			queue_work(ipoib_workqueue, &priv->cm.rx_reap_task);
+			queue_work(priv->wq, &priv->cm.rx_reap_task);
 			spin_unlock_irqrestore(&priv->lock, flags);
 		} else
 			ipoib_warn(priv, "cm recv completion event with wrid %d (> %d)\n",
@@ -603,7 +603,7 @@ void ipoib_cm_handle_rx_wc(struct net_device *dev, struct ib_wc *wc)
 				spin_lock_irqsave(&priv->lock, flags);
 				list_move(&p->list, &priv->cm.rx_reap_list);
 				spin_unlock_irqrestore(&priv->lock, flags);
-				queue_work(ipoib_workqueue, &priv->cm.rx_reap_task);
+				queue_work(priv->wq, &priv->cm.rx_reap_task);
 			}
 			return;
 		}
@@ -827,7 +827,7 @@ void ipoib_cm_handle_tx_wc(struct net_device *dev, struct ib_wc *wc)
 
 		if (test_and_clear_bit(IPOIB_FLAG_INITIALIZED, &tx->flags)) {
 			list_move(&tx->list, &priv->cm.reap_list);
-			queue_work(ipoib_workqueue, &priv->cm.reap_task);
+			queue_work(priv->wq, &priv->cm.reap_task);
 		}
 
 		clear_bit(IPOIB_FLAG_OPER_UP, &tx->flags);
@@ -1255,7 +1255,7 @@ static int ipoib_cm_tx_handler(struct ib_cm_id *cm_id,
 
 		if (test_and_clear_bit(IPOIB_FLAG_INITIALIZED, &tx->flags)) {
 			list_move(&tx->list, &priv->cm.reap_list);
-			queue_work(ipoib_workqueue, &priv->cm.reap_task);
+			queue_work(priv->wq, &priv->cm.reap_task);
 		}
 
 		spin_unlock_irqrestore(&priv->lock, flags);
@@ -1284,7 +1284,7 @@ struct ipoib_cm_tx *ipoib_cm_create_tx(struct net_device *dev, struct ipoib_path
 	tx->dev = dev;
 	list_add(&tx->list, &priv->cm.start_list);
 	set_bit(IPOIB_FLAG_INITIALIZED, &tx->flags);
-	queue_work(ipoib_workqueue, &priv->cm.start_task);
+	queue_work(priv->wq, &priv->cm.start_task);
 	return tx;
 }
 
@@ -1295,7 +1295,7 @@ void ipoib_cm_destroy_tx(struct ipoib_cm_tx *tx)
 	if (test_and_clear_bit(IPOIB_FLAG_INITIALIZED, &tx->flags)) {
 		spin_lock_irqsave(&priv->lock, flags);
 		list_move(&tx->list, &priv->cm.reap_list);
-		queue_work(ipoib_workqueue, &priv->cm.reap_task);
+		queue_work(priv->wq, &priv->cm.reap_task);
 		ipoib_dbg(priv, "Reap connection for gid %pI6\n",
 			  tx->neigh->daddr + 4);
 		tx->neigh = NULL;
@@ -1417,7 +1417,7 @@ void ipoib_cm_skb_too_long(struct net_device *dev, struct sk_buff *skb,
 
 	skb_queue_tail(&priv->cm.skb_queue, skb);
 	if (e)
-		queue_work(ipoib_workqueue, &priv->cm.skb_task);
+		queue_work(priv->wq, &priv->cm.skb_task);
 }
 
 static void ipoib_cm_rx_reap(struct work_struct *work)
@@ -1450,7 +1450,7 @@ static void ipoib_cm_stale_task(struct work_struct *work)
 	}
 
 	if (!list_empty(&priv->cm.passive_ids))
-		queue_delayed_work(ipoib_workqueue,
+		queue_delayed_work(priv->wq,
 				   &priv->cm.stale_task, IPOIB_CM_RX_DELAY);
 	spin_unlock_irq(&priv->lock);
 }
diff --git a/drivers/infiniband/ulp/ipoib/ipoib_ib.c b/drivers/infiniband/ulp/ipoib/ipoib_ib.c
index cb02466a0eb9..2a56b7a11a92 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_ib.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_ib.c
@@ -655,7 +655,7 @@ void ipoib_reap_ah(struct work_struct *work)
 	__ipoib_reap_ah(dev);
 
 	if (!test_bit(IPOIB_STOP_REAPER, &priv->flags))
-		queue_delayed_work(ipoib_workqueue, &priv->ah_reap_task,
+		queue_delayed_work(priv->wq, &priv->ah_reap_task,
 				   round_jiffies_relative(HZ));
 }
 
@@ -665,7 +665,7 @@ static void ipoib_flush_ah(struct net_device *dev, int flush)
 
 	cancel_delayed_work(&priv->ah_reap_task);
 	if (flush)
-		flush_workqueue(ipoib_workqueue);
+		flush_workqueue(priv->wq);
 	ipoib_reap_ah(&priv->ah_reap_task.work);
 }
 
@@ -714,7 +714,7 @@ int ipoib_ib_dev_open(struct net_device *dev, int flush)
 	}
 
 	clear_bit(IPOIB_STOP_REAPER, &priv->flags);
-	queue_delayed_work(ipoib_workqueue, &priv->ah_reap_task,
+	queue_delayed_work(priv->wq, &priv->ah_reap_task,
 			   round_jiffies_relative(HZ));
 
 	if (!test_and_set_bit(IPOIB_FLAG_INITIALIZED, &priv->flags))
diff --git a/drivers/infiniband/ulp/ipoib/ipoib_main.c b/drivers/infiniband/ulp/ipoib/ipoib_main.c
index 98c738d827d1..4be80bec93ca 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_main.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_main.c
@@ -839,7 +839,7 @@ static void ipoib_set_mcast_list(struct net_device *dev)
 		return;
 	}
 
-	queue_work(ipoib_workqueue, &priv->restart_task);
+	queue_work(priv->wq, &priv->restart_task);
 }
 
 static int ipoib_get_iflink(const struct net_device *dev)
@@ -961,7 +961,7 @@ static void ipoib_reap_neigh(struct work_struct *work)
 	__ipoib_reap_neigh(priv);
 
 	if (!test_bit(IPOIB_STOP_NEIGH_GC, &priv->flags))
-		queue_delayed_work(ipoib_workqueue, &priv->neigh_reap_task,
+		queue_delayed_work(priv->wq, &priv->neigh_reap_task,
 				   arp_tbl.gc_interval);
 }
 
@@ -1140,7 +1140,7 @@ static int ipoib_neigh_hash_init(struct ipoib_dev_priv *priv)
 
 	/* start garbage collection */
 	clear_bit(IPOIB_STOP_NEIGH_GC, &priv->flags);
-	queue_delayed_work(ipoib_workqueue, &priv->neigh_reap_task,
+	queue_delayed_work(priv->wq, &priv->neigh_reap_task,
 			   arp_tbl.gc_interval);
 
 	return 0;
@@ -1651,10 +1651,11 @@ sysfs_failed:
 
 register_failed:
 	ib_unregister_event_handler(&priv->event_handler);
+	flush_workqueue(ipoib_workqueue);
 	/* Stop GC if started before flush */
 	set_bit(IPOIB_STOP_NEIGH_GC, &priv->flags);
 	cancel_delayed_work(&priv->neigh_reap_task);
-	flush_workqueue(ipoib_workqueue);
+	flush_workqueue(priv->wq);
 
 event_failed:
 	ipoib_dev_cleanup(priv->dev);
@@ -1717,6 +1718,7 @@ static void ipoib_remove_one(struct ib_device *device)
 
 	list_for_each_entry_safe(priv, tmp, dev_list, list) {
 		ib_unregister_event_handler(&priv->event_handler);
+		flush_workqueue(ipoib_workqueue);
 
 		rtnl_lock();
 		dev_change_flags(priv->dev, priv->dev->flags & ~IFF_UP);
@@ -1725,7 +1727,7 @@ static void ipoib_remove_one(struct ib_device *device)
 		/* Stop GC */
 		set_bit(IPOIB_STOP_NEIGH_GC, &priv->flags);
 		cancel_delayed_work(&priv->neigh_reap_task);
-		flush_workqueue(ipoib_workqueue);
+		flush_workqueue(priv->wq);
 
 		unregister_netdev(priv->dev);
 		free_netdev(priv->dev);
@@ -1760,14 +1762,16 @@ static int __init ipoib_init_module(void)
 		return ret;
 
 	/*
-	 * We create our own workqueue mainly because we want to be
-	 * able to flush it when devices are being removed.  We can't
-	 * use schedule_work()/flush_scheduled_work() because both
-	 * unregister_netdev() and linkwatch_event take the rtnl lock,
-	 * so flush_scheduled_work() can deadlock during device
-	 * removal.
+	 * We create a global workqueue here that is used for all flush
+	 * operations.  However, if you attempt to flush a workqueue
+	 * from a task on that same workqueue, it deadlocks the system.
+	 * We want to be able to flush the tasks associated with a
+	 * specific net device, so we also create a workqueue for each
+	 * netdevice.  We queue up the tasks for that device only on
+	 * its private workqueue, and we only queue up flush events
+	 * on our global flush workqueue.  This avoids the deadlocks.
 	 */
-	ipoib_workqueue = create_singlethread_workqueue("ipoib");
+	ipoib_workqueue = create_singlethread_workqueue("ipoib_flush");
 	if (!ipoib_workqueue) {
 		ret = -ENOMEM;
 		goto err_fs;
diff --git a/drivers/infiniband/ulp/ipoib/ipoib_multicast.c b/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
index c63a598d0b41..9d3c1ed576ea 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
@@ -403,16 +403,15 @@ static int ipoib_mcast_join_complete(int status,
 		mcast->backoff = 1;
 		mutex_lock(&mcast_mutex);
 		if (test_bit(IPOIB_MCAST_RUN, &priv->flags))
-			queue_delayed_work(ipoib_workqueue,
-					   &priv->mcast_task, 0);
+			queue_delayed_work(priv->wq, &priv->mcast_task, 0);
 		mutex_unlock(&mcast_mutex);
 
 		/*
-		 * Defer carrier on work to ipoib_workqueue to avoid a
+		 * Defer carrier on work to priv->wq to avoid a
 		 * deadlock on rtnl_lock here.
 		 */
 		if (mcast == priv->broadcast)
-			queue_work(ipoib_workqueue, &priv->carrier_on_task);
+			queue_work(priv->wq, &priv->carrier_on_task);
 
 		status = 0;
 		goto out;
@@ -438,7 +437,7 @@ static int ipoib_mcast_join_complete(int status,
 	mutex_lock(&mcast_mutex);
 	spin_lock_irq(&priv->lock);
 	if (test_bit(IPOIB_MCAST_RUN, &priv->flags))
-		queue_delayed_work(ipoib_workqueue, &priv->mcast_task,
+		queue_delayed_work(priv->wq, &priv->mcast_task,
 				   mcast->backoff * HZ);
 	spin_unlock_irq(&priv->lock);
 	mutex_unlock(&mcast_mutex);
@@ -511,8 +510,7 @@ static void ipoib_mcast_join(struct net_device *dev, struct ipoib_mcast *mcast,
 
 		mutex_lock(&mcast_mutex);
 		if (test_bit(IPOIB_MCAST_RUN, &priv->flags))
-			queue_delayed_work(ipoib_workqueue,
-					   &priv->mcast_task,
+			queue_delayed_work(priv->wq, &priv->mcast_task,
 					   mcast->backoff * HZ);
 		mutex_unlock(&mcast_mutex);
 	}
@@ -552,8 +550,8 @@ void ipoib_mcast_join_task(struct work_struct *work)
 			ipoib_warn(priv, "failed to allocate broadcast group\n");
 			mutex_lock(&mcast_mutex);
 			if (test_bit(IPOIB_MCAST_RUN, &priv->flags))
-				queue_delayed_work(ipoib_workqueue,
-						   &priv->mcast_task, HZ);
+				queue_delayed_work(priv->wq, &priv->mcast_task,
+						   HZ);
 			mutex_unlock(&mcast_mutex);
 			return;
 		}
@@ -609,7 +607,7 @@ int ipoib_mcast_start_thread(struct net_device *dev)
 
 	mutex_lock(&mcast_mutex);
 	if (!test_and_set_bit(IPOIB_MCAST_RUN, &priv->flags))
-		queue_delayed_work(ipoib_workqueue, &priv->mcast_task, 0);
+		queue_delayed_work(priv->wq, &priv->mcast_task, 0);
 	mutex_unlock(&mcast_mutex);
 
 	return 0;
@@ -627,7 +625,7 @@ int ipoib_mcast_stop_thread(struct net_device *dev, int flush)
 	mutex_unlock(&mcast_mutex);
 
 	if (flush)
-		flush_workqueue(ipoib_workqueue);
+		flush_workqueue(priv->wq);
 
 	return 0;
 }
diff --git a/drivers/infiniband/ulp/ipoib/ipoib_verbs.c b/drivers/infiniband/ulp/ipoib/ipoib_verbs.c
index c56d5d44c53b..34628403fd83 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_verbs.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_verbs.c
@@ -157,6 +157,16 @@ int ipoib_transport_dev_init(struct net_device *dev, struct ib_device *ca)
 		goto out_free_pd;
 	}
 
+	/*
+	 * the various IPoIB tasks assume they will never race against
+	 * themselves, so always use a single thread workqueue
+	 */
+	priv->wq = create_singlethread_workqueue("ipoib_wq");
+	if (!priv->wq) {
+		printk(KERN_WARNING "ipoib: failed to allocate device WQ\n");
+		goto out_free_mr;
+	}
+
 	size = ipoib_recvq_size + 1;
 	ret = ipoib_cm_dev_init(dev);
 	if (!ret) {
@@ -165,12 +175,13 @@ int ipoib_transport_dev_init(struct net_device *dev, struct ib_device *ca)
 			size += ipoib_recvq_size + 1; /* 1 extra for rx_drain_qp */
 		else
 			size += ipoib_recvq_size * ipoib_max_conn_qp;
-	}
+	} else
+		goto out_free_wq;
 
 	priv->recv_cq = ib_create_cq(priv->ca, ipoib_ib_completion, NULL, dev, size, 0);
 	if (IS_ERR(priv->recv_cq)) {
 		printk(KERN_WARNING "%s: failed to create receive CQ\n", ca->name);
-		goto out_free_mr;
+		goto out_cm_dev_cleanup;
 	}
 
 	priv->send_cq = ib_create_cq(priv->ca, ipoib_send_comp_handler, NULL,
@@ -236,12 +247,19 @@ out_free_send_cq:
 out_free_recv_cq:
 	ib_destroy_cq(priv->recv_cq);
 
+out_cm_dev_cleanup:
+	ipoib_cm_dev_cleanup(dev);
+
+out_free_wq:
+	destroy_workqueue(priv->wq);
+	priv->wq = NULL;
+
 out_free_mr:
 	ib_dereg_mr(priv->mr);
-	ipoib_cm_dev_cleanup(dev);
 
 out_free_pd:
 	ib_dealloc_pd(priv->pd);
+
 	return -ENODEV;
 }
 
@@ -265,11 +283,18 @@ void ipoib_transport_dev_cleanup(struct net_device *dev)
 
 	ipoib_cm_dev_cleanup(dev);
 
+	if (priv->wq) {
+		flush_workqueue(priv->wq);
+		destroy_workqueue(priv->wq);
+		priv->wq = NULL;
+	}
+
 	if (ib_dereg_mr(priv->mr))
 		ipoib_warn(priv, "ib_dereg_mr failed\n");
 
 	if (ib_dealloc_pd(priv->pd))
 		ipoib_warn(priv, "ib_dealloc_pd failed\n");
+
 }
 
 void ipoib_event(struct ib_event_handler *handler,