tree aa51f1a4919a683130007c0189e0b0a29fccd302
parent 0001ec565db7ed01a6cc9575453900801bd0841b
author Scott Bauer <scott.bauer@intel.com> 1513618088 -0700
committer Mike Snitzer <snitzer@redhat.com> 1516198560 -0500

dm: add unstriped target

This device mapper "unstriped" target remaps and unstripes I/O so it
is issued solely on a single drive in a HW RAID0 or dm-striped target.

In a 4 drive HW RAID0 the striped target exposes 1/4th of the LBA range
as a virtual drive.  Each I/O to that virtual drive will only be issued
to the 1 drive that was selected of the 4 drives in the HW RAID0.

This unstriped target is most useful for Intel NVMe drives that have
multiple cores but that do not have firmware control to pin separate LBA
ranges to each discrete cpu core.

Signed-off-by: Scott Bauer <scott.bauer@intel.com>
Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Acked-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>