IPoIB: Yet another fix for send-only joins

Even after the last fix, it's still possible for a send-only join to
start before the join for the broadcast group has finished.  This
could cause us to create a multicast group using attributes from the
broadcast group that haven't been initialized yet, so we would use
garbage for the Q_Key, etc.  Fix this by waiting until the broadcast
group's attached flag is set before starting send-only joins.

Signed-off-by: Roland Dreier <rolandd@cisco.com>

1 files changed, 10 insertions, 5 deletions

diff --git a/drivers/infiniband/ulp/ipoib/ipoib_multicast.c b/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
index 932bf139a65d..a2408d7ec598 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
@@ -533,8 +533,10 @@ void ipoib_mcast_join_task(void *dev_ptr)
         }
 
         if (!priv->broadcast) {
-                priv->broadcast = ipoib_mcast_alloc(dev, 1);
-                if (!priv->broadcast) {
+                struct ipoib_mcast *broadcast;
+
+                broadcast = ipoib_mcast_alloc(dev, 1);
+                if (!broadcast) {
                         ipoib_warn(priv, "failed to allocate broadcast group\n");
                         mutex_lock(&mcast_mutex);
                         if (test_bit(IPOIB_MCAST_RUN, &priv->flags))
@@ -544,10 +546,11 @@ void ipoib_mcast_join_task(void *dev_ptr)
                         return;
                 }
 
-                memcpy(priv->broadcast->mcmember.mgid.raw, priv->dev->broadcast + 4,
+                spin_lock_irq(&priv->lock);
+                memcpy(broadcast->mcmember.mgid.raw, priv->dev->broadcast + 4,
                        sizeof (union ib_gid));
+                priv->broadcast = broadcast;
 
-                spin_lock_irq(&priv->lock);
                 __ipoib_mcast_add(dev, priv->broadcast);
                 spin_unlock_irq(&priv->lock);
         }
@@ -701,7 +704,9 @@ void ipoib_mcast_send(struct net_device *dev, union ib_gid *mgid,
          */
         spin_lock(&priv->lock);
 
-        if (!test_bit(IPOIB_MCAST_STARTED, &priv->flags) || !priv->broadcast) {
+        if (!test_bit(IPOIB_MCAST_STARTED, &priv->flags)        ||
+            !priv->broadcast                                    ||
+            !test_bit(IPOIB_MCAST_FLAG_ATTACHED, &priv->broadcast->flags)) {
                 ++priv->stats.tx_dropped;
                 dev_kfree_skb_any(skb);
                 goto unlock;