From a274097b341b09d8356762317bace48e1f2024ae Mon Sep 17 00:00:00 2001
From: Markus Hilger <Markus.Hilger@de.ibm.com>
Date: Tue, 12 May 2020 13:41:45 +0200
Subject: [PATCH] Do not set MTU for InfiniBand slaves Slaves should have no
 MTU set. This should be set globally on the bond interface. Furthermore, RHEL
 8.0 does not correctly set the given MTU as shown below. This breaks any IB
 bonds with non-default (2044) MTU.

$ # IB slave with 4092 MTU
$ nmcli con add type Infiniband con-name slave-ib1-mtu mtu 4092 ifname ib1 master ibbond0 slave-type bond
$ # IB slave without MTU
$ nmcli con add type Infiniband con-name slave-ib1-wo-mtu ifname ib1 master ibbond0 slave-type bond

$ # should be 4092, but is 2044 instead
$ nmcli -f infiniband.mtu con show slave-ib1-mtu
infiniband.mtu:                         2044

$ grep MTU /etc/sysconfig/network-scripts/ifcfg-slave-ib1-*
/etc/sysconfig/network-scripts/ifcfg-slave-ib1-mtu:MTU=2044

$ # is auto :)
$ nmcli -f infiniband.mtu con show slave-ib1-wo-mtu
infiniband.mtu:                         auto
---
 xCAT/postscripts/nicutils.sh | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/xCAT/postscripts/nicutils.sh b/xCAT/postscripts/nicutils.sh
index f00407d02..780b1da7b 100755
--- a/xCAT/postscripts/nicutils.sh
+++ b/xCAT/postscripts/nicutils.sh
@@ -2246,6 +2246,10 @@ function create_bond_interface_nmcli {
             $ip link set dev $ifslave down 
             wait_for_ifstate $ifslave DOWN 20 2
         fi
+        # InfiniBand slaves should have no MTU defined, only the bond interface
+        if [ "$slave_type" = "Infiniband" ]; then
+            _mtu=""
+        fi
         cmd="$nmcli con add type $slave_type con-name $xcat_slave_con $_mtu ifname $ifslave master $xcat_con_name slave-type bond autoconnect yes connection.autoconnect-priority 9 connection.autoconnect-retries 0"
         log_info $cmd
         $cmd