IPoIB: Remove priv->mcast_mutex

No need for a mutex around calls to ib_attach_mcast/ib_detach_mcast
since these operations are synchronized at the HW driver layer.
Signed-off-by: Eli Cohen <eli@mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

drivers/infiniband/ulp/ipoib/ipoib.h

@@ -277,7 +277,6 @@ struct ipoib_dev_priv {
 
 	unsigned long flags;
 
-	struct mutex mcast_mutex;
 	struct mutex vlan_mutex;
 
 	struct rb_root  path_tree;

drivers/infiniband/ulp/ipoib/ipoib_main.c

@@ -1072,7 +1072,6 @@ static void ipoib_setup(struct net_device *dev)
 	spin_lock_init(&priv->lock);
 	spin_lock_init(&priv->tx_lock);
 
-	mutex_init(&priv->mcast_mutex);
 	mutex_init(&priv->vlan_mutex);
 
 	INIT_LIST_HEAD(&priv->path_list);

drivers/infiniband/ulp/ipoib/ipoib_verbs.c

@@ -61,9 +61,7 @@ int ipoib_mcast_attach(struct net_device *dev, u16 mlid, union ib_gid *mgid)
 	}
 
 	/* attach QP to multicast group */
-	mutex_lock(&priv->mcast_mutex);
 	ret = ib_attach_mcast(priv->qp, mgid, mlid);
-	mutex_unlock(&priv->mcast_mutex);
 	if (ret)
 		ipoib_warn(priv, "failed to attach to multicast group, ret = %d\n", ret);
 
@@ -77,9 +75,7 @@ int ipoib_mcast_detach(struct net_device *dev, u16 mlid, union ib_gid *mgid)
 	struct ipoib_dev_priv *priv = netdev_priv(dev);
 	int ret;
 
-	mutex_lock(&priv->mcast_mutex);
 	ret = ib_detach_mcast(priv->qp, mgid, mlid);
-	mutex_unlock(&priv->mcast_mutex);
 	if (ret)
 		ipoib_warn(priv, "ib_detach_mcast failed (result = %d)\n", ret);