Revert "IPoIB: Make ipoib_mcast_stop_thread flush the workqueue"
This reverts commit bb42a6dd02fb2901a69dbec2358810735b14b186.
The series of IPoIB bug fixes that went into 3.19-rc1 introduce
regressions, and after trying to sort things out, we decided to revert
to 3.18's IPoIB driver and get things right for 3.20.
Signed-off-by: Roland Dreier <roland@purestorage.com>
diff --git a/drivers/infiniband/ulp/ipoib/ipoib_multicast.c b/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
index bc50dd0..845f910 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
@@ -648,7 +648,7 @@
return 0;
}
-int ipoib_mcast_stop_thread(struct net_device *dev)
+int ipoib_mcast_stop_thread(struct net_device *dev, int flush)
{
struct ipoib_dev_priv *priv = netdev_priv(dev);
@@ -659,7 +659,8 @@
cancel_delayed_work(&priv->mcast_task);
mutex_unlock(&mcast_mutex);
- flush_workqueue(priv->wq);
+ if (flush)
+ flush_workqueue(priv->wq);
return 0;
}
@@ -837,6 +838,8 @@
ipoib_dbg_mcast(priv, "restarting multicast task\n");
+ ipoib_mcast_stop_thread(dev, 0);
+
local_irq_save(flags);
netif_addr_lock(dev);
spin_lock(&priv->lock);
@@ -933,10 +936,13 @@
* We have to cancel outside of the spinlock, but we have to
* take the rtnl lock or else we race with the removal of
* entries from the remove list in mcast_dev_flush as part
- * of ipoib_stop(). We detect the drop of the ADMIN_UP flag
- * to signal that we have hit this particular race, and we
- * return since we know we don't need to do anything else
- * anyway.
+ * of ipoib_stop() which will call mcast_stop_thread with
+ * flush == 1 while holding the rtnl lock, and the
+ * flush_workqueue won't complete until this restart_mcast_task
+ * completes. So do like the carrier on task and attempt to
+ * take the rtnl lock, but if we can't before the ADMIN_UP flag
+ * goes away, then just return and know that the remove list will
+ * get flushed later by mcast_stop_thread.
*/
while (!rtnl_trylock()) {
if (!test_bit(IPOIB_FLAG_ADMIN_UP, &priv->flags))
@@ -948,9 +954,6 @@
ipoib_mcast_leave(mcast->dev, mcast);
ipoib_mcast_free(mcast);
}
- /*
- * Restart our join task if needed
- */
ipoib_mcast_start_thread(dev);
rtnl_unlock();
}