[ofw] enable/disable device changes IPoIB physical address??

[Sean Hefty]

>We're attempting to create some automated scripts to change IP settings
>w/ IPoIB adapters, and running into some strange issues.  Thus far,
>we've been trying to identify the correct NIC/port by the physical
>address, which seems to be the same on all hosts.  This is fine, as we
>were looking for a reliable way to identify the port each time.
>However, it's *not* reliable.  For some reason, disabling and
>re-enabling the device actually changes the physical address that
>ipconfig reports each time.  Only a reboot of the host resets it to the
>initial address (02-00-00-00-00-01).  We're also guessing that the phys
>addy that gets assigned on each re-enabling of the device is based on
>some timestamp, as the disparity between them increases when there is
>more time between the re-enabling.  Why is this address ever changing in
>the first place?

The IPoIB L2 address includes its QPN, which can change by disabling /
re-enabling the device.  The L2 address also includes the port GID, which
identifies the correct NIC/port.  Your scripts would likely work like you expect
if you use only the GID portion of the L2 address (bytes 4-20).

- Sean