[title]
Identify I/O devices that are in use although they are on the exclusion list

[description]
The I/O device exclusion list prevents Linux from sensing and analyzing
I/O devices that are available to Linux but not required.

An initial exclusion list can be included in the boot configuration using
the "cio_ignore" kernel parameter. On a running Linux instance, the list
can be changed temporarily through the /proc/cio_ignore procfs interface or
with the "cio_ignore" command. Rebooting restores the exclusion list
of the boot configuration.

I/O devices that are in use (online) might be required and should then not be
on the exclusion list. If these devices become unavailable and reappear after
some time, they are ignored and remain unavailable to Linux. If they are added
to the cio_ignore parameter in the boot configuration, they will also be
unavailable after rebooting Linux.
