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>

diff --git a/drivers/infiniband/ulp/ipoib/ipoib_multicast.c b/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
index 932bf139a65de7ebb90e2fcc9ee15c8cb96d3ce8..a2408d7ec5986cb3e69b3988f9a6c5a35fbf118f 100644 (file)
--- 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;