zfs: re-use of geom consumer in vdev_geom

[Andriy Gapon]

Does anyone know why we re-use GEOM consumers in vdev_geom?
I mean, it seems that multiple ZFS vdevs could be using the same consumer
attached to a particular provider. When is this needed?
Couldn't every vdev have its won consumer?
Do we have situations where more than vdev would use the same provider in the
read-write mode?  Or one vdev would want the read-write mode while another would
have it in read-only mode?

Thank you.

-- 
Andriy Gapon