From: Feras Daoud <ferasda@xxxxxxxxxxxx> In datagram mode, the IB UD (Unreliable Datagram) transport is used so the MTU of the interface is equal to the IB L2 MTU minus the IPoIB encapsulation header. Any request to change the MTU value above the maximum range will change the MTU to the max allowed, but will not show any warning message. An ipoib_warn is issued in such cases, letting the user know that even though the value is legal, it can't be currently applied. Signed-off-by: Feras Daoud <ferasda@xxxxxxxxxxxx> Signed-off-by: Noa Osherovich <noaos@xxxxxxxxxxxx> Signed-off-by: Leon Romanovsky <leon@xxxxxxxxxx> --- drivers/infiniband/ulp/ipoib/ipoib_main.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/infiniband/ulp/ipoib/ipoib_main.c b/drivers/infiniband/ulp/ipoib/ipoib_main.c index 3ce0765..a550cc6 100644 --- a/drivers/infiniband/ulp/ipoib/ipoib_main.c +++ b/drivers/infiniband/ulp/ipoib/ipoib_main.c @@ -229,6 +229,10 @@ static int ipoib_change_mtu(struct net_device *dev, int new_mtu) priv->admin_mtu = new_mtu; + if (priv->mcast_mtu < priv->admin_mtu) + ipoib_warn(priv, "MTU must be smaller than mcast_mtu (%u)\n", + priv->mcast_mtu); + dev->mtu = min(priv->mcast_mtu, priv->admin_mtu); return 0; -- 2.10.2 -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
