[PATCH] IPoIB: Fix device removal race

Currently we may have work scheduled in default kernel workqueue when
the device is going down. The device could get freed before this
workqueue gets serviced. I am actually seeing this causing system
hangs.

The following patch fixes this by using ipoib_workqueue which gets
flushed when the device is going down.

Signed-off-by: Michael S. Tsirkin <[e-mail]>
Signed-off-by: Roland Dreier <[e-mail]>

drivers/infiniband/ulp/ipoib/ipoib_main.c

···
 {
 	struct ipoib_dev_priv *priv = netdev_priv(dev);
 
-	schedule_work(&priv->restart_task);
+	queue_work(ipoib_workqueue, &priv->restart_task);
 }
 
 static void ipoib_neigh_destructor(struct neighbour *n)