IPoIB: Copy child MTU from parent

When creating a child interface, copy the MTU information from the
parent.  Otherwise when the child's multicast join completes, the MTU
will not be updated since the code does

	dev->mtu = min(priv->mcast_mtu, priv->admin_mtu);

and priv->admin_mtu will be set to 0.

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

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/infiniband/ulp/ipoib/ipoib_vlan.c b/drivers/infiniband/ulp/ipoib/ipoib_vlan.c
index 431fdeaa2dc..1cdb5cfb0ff 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_vlan.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_vlan.c
@@ -90,6 +90,9 @@ int ipoib_vlan_add(struct net_device *pdev, unsigned short pkey)
         }
 
         priv->max_ib_mtu = ppriv->max_ib_mtu;
+        /* MTU will be reset when mcast join happens */
+        priv->dev->mtu   = IPOIB_UD_MTU(priv->max_ib_mtu);
+        priv->mcast_mtu  = priv->admin_mtu = priv->dev->mtu;
         set_bit(IPOIB_FLAG_SUBINTERFACE, &priv->flags);
 
         priv->pkey = pkey;