IPoIB: Move ipoib_ib_dev_flush() to ipoib workqueue

Move ipoib_ib_dev_flush() to ipoib's workqueue.  This keeps it ordered
with respect to other work scheduled by the ipoib driver.  This fixes
problems with races, for example:
 - ipoib_ib_dev_flush() has started running because of an IB event
 - user does ifconfig ib0 down
 - ipoib_mcast_stop_thread() gets called twice and waits for the same
   completion twice

Signed-off-by: Jack Morgenstein <jackm@mellanox.co.il>
Signed-off-by: Michael S. Tsirkin <mst@mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

4 files changed, 14 insertions, 7 deletions

diff --git a/drivers/infiniband/ulp/ipoib/ipoib.h b/drivers/infiniband/ulp/ipoib/ipoib.h
index 638eff745b2f..1251f86ec856 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib.h
+++ b/drivers/infiniband/ulp/ipoib/ipoib.h
@@ -259,7 +259,7 @@ void ipoib_ib_dev_cleanup(struct net_device *dev);
 
 int ipoib_ib_dev_open(struct net_device *dev);
 int ipoib_ib_dev_up(struct net_device *dev);
-int ipoib_ib_dev_down(struct net_device *dev);
+int ipoib_ib_dev_down(struct net_device *dev, int flush);
 int ipoib_ib_dev_stop(struct net_device *dev);
 
 int ipoib_dev_init(struct net_device *dev, struct ib_device *ca, int port);
diff --git a/drivers/infiniband/ulp/ipoib/ipoib_ib.c b/drivers/infiniband/ulp/ipoib/ipoib_ib.c
index 5a5367d10875..a1f5a05f2f36 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_ib.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_ib.c
@@ -435,7 +435,7 @@ int ipoib_ib_dev_up(struct net_device *dev)
         return ipoib_mcast_start_thread(dev);
 }
 
-int ipoib_ib_dev_down(struct net_device *dev)
+int ipoib_ib_dev_down(struct net_device *dev, int flush)
 {
         struct ipoib_dev_priv *priv = netdev_priv(dev);
 
@@ -450,10 +450,11 @@ int ipoib_ib_dev_down(struct net_device *dev)
                 set_bit(IPOIB_PKEY_STOP, &priv->flags);
                 cancel_delayed_work(&priv->pkey_task);
                 mutex_unlock(&pkey_mutex);
-                flush_workqueue(ipoib_workqueue);
+                if (flush)
+                        flush_workqueue(ipoib_workqueue);
         }
 
-        ipoib_mcast_stop_thread(dev, 1);
+        ipoib_mcast_stop_thread(dev, flush);
         ipoib_mcast_dev_flush(dev);
 
         ipoib_flush_paths(dev);
@@ -591,7 +592,7 @@ void ipoib_ib_dev_flush(void *_dev)
 
         ipoib_dbg(priv, "flushing\n");
 
-        ipoib_ib_dev_down(dev);
+        ipoib_ib_dev_down(dev, 0);
 
         /*
          * The device could have been brought down between the start and when
diff --git a/drivers/infiniband/ulp/ipoib/ipoib_main.c b/drivers/infiniband/ulp/ipoib/ipoib_main.c
index c3b5f79d1168..1633aadae421 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_main.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_main.c
@@ -133,7 +133,13 @@ static int ipoib_stop(struct net_device *dev)
 
         netif_stop_queue(dev);
 
-        ipoib_ib_dev_down(dev);
+        /*
+         * Now flush workqueue to make sure a scheduled task doesn't
+         * bring our internal state back up.
+         */
+        flush_workqueue(ipoib_workqueue);
+
+        ipoib_ib_dev_down(dev, 1);
         ipoib_ib_dev_stop(dev);
 
         if (!test_bit(IPOIB_FLAG_SUBINTERFACE, &priv->flags)) {
diff --git a/drivers/infiniband/ulp/ipoib/ipoib_verbs.c b/drivers/infiniband/ulp/ipoib/ipoib_verbs.c
index faaf10e5fc7b..18d2f53ec34c 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_verbs.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_verbs.c
@@ -255,6 +255,6 @@ void ipoib_event(struct ib_event_handler *handler,
             record->event == IB_EVENT_LID_CHANGE  ||
             record->event == IB_EVENT_SM_CHANGE) {
                 ipoib_dbg(priv, "Port active event\n");
-                schedule_work(&priv->flush_task);
+                queue_work(ipoib_workqueue, &priv->flush_task);
         }
 }