IPoIB: Wait for join to finish before freeing mcast struct

ipoib_mcast_restart_task() might free an mcast object while a join
request is still outstanding, leading to an oops when the query
completes.  Fix this by waiting for query to complete, similar to what
ipoib_stop_thread() is doing.  The wait for mcast completion code is
consolidated in wait_for_mcast_join().

Signed-off-by: Eli Cohen <eli@mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

diff --git a/drivers/infiniband/ulp/ipoib/ipoib_multicast.c b/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
index 07b9826..1dae4b2 100644 (file)
--- a/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
@@ -609,6 +609,22 @@ int ipoib_mcast_start_thread(struct net_device *dev)
        return 0;
 }
 
+static void wait_for_mcast_join(struct ipoib_dev_priv *priv,
+                               struct ipoib_mcast *mcast)
+{
+       spin_lock_irq(&priv->lock);
+       if (mcast && mcast->query) {
+               ib_sa_cancel_query(mcast->query_id, mcast->query);
+               mcast->query = NULL;
+               spin_unlock_irq(&priv->lock);
+               ipoib_dbg_mcast(priv, "waiting for MGID " IPOIB_GID_FMT "\n",
+                               IPOIB_GID_ARG(mcast->mcmember.mgid));
+               wait_for_completion(&mcast->done);
+       }
+       else
+               spin_unlock_irq(&priv->lock);
+}
+
 int ipoib_mcast_stop_thread(struct net_device *dev, int flush)
 {
        struct ipoib_dev_priv *priv = netdev_priv(dev);
@@ -628,28 +644,10 @@ int ipoib_mcast_stop_thread(struct net_device *dev, int flush)
        if (flush)
                flush_workqueue(ipoib_workqueue);
 
-       spin_lock_irq(&priv->lock);
-       if (priv->broadcast && priv->broadcast->query) {
-               ib_sa_cancel_query(priv->broadcast->query_id, priv->broadcast->query);
-               priv->broadcast->query = NULL;
-               spin_unlock_irq(&priv->lock);
-               ipoib_dbg_mcast(priv, "waiting for bcast\n");
-               wait_for_completion(&priv->broadcast->done);
-       } else
-               spin_unlock_irq(&priv->lock);
+       wait_for_mcast_join(priv, priv->broadcast);
 
-       list_for_each_entry(mcast, &priv->multicast_list, list) {
-               spin_lock_irq(&priv->lock);
-               if (mcast->query) {
-                       ib_sa_cancel_query(mcast->query_id, mcast->query);
-                       mcast->query = NULL;
-                       spin_unlock_irq(&priv->lock);
-                       ipoib_dbg_mcast(priv, "waiting for MGID " IPOIB_GID_FMT "\n",
-                                       IPOIB_GID_ARG(mcast->mcmember.mgid));
-                       wait_for_completion(&mcast->done);
-               } else
-                       spin_unlock_irq(&priv->lock);
-       }
+       list_for_each_entry(mcast, &priv->multicast_list, list)
+               wait_for_mcast_join(priv, mcast);
 
        return 0;
 }
@@ -902,6 +900,7 @@ void ipoib_mcast_restart_task(void *dev_ptr)
 
        /* We have to cancel outside of the spinlock */
        list_for_each_entry_safe(mcast, tmcast, &remove_list, list) {
+               wait_for_mcast_join(priv, mcast);
                ipoib_mcast_leave(mcast->dev, mcast);
                ipoib_mcast_free(mcast);
        }