On Fri, Nov 10, 2017 at 05:52:36AM +0100, Christoph Hellwig wrote:

quoted

If we've CMIC capabilities, we'll use the subsys->instance; if we don't
have CMIC, we use the ctrl->instance. 

Since the two instances are independent of each other, they can create
duplicate names.

To fix, I think we'll need to always use the subsys instance for
consistency if CONFIG_NVME_MULTIPATH=y.

Yes, we should.  But once we do that we should just always use
subsys->instance, as it will always be the same as ctrl->instance
for CONFIG_NVME_MULTIPATH=n.

Scrap that.  Of course they aren't always the same in the
CONFIG_NVME_MULTIPATH=n.  We'll need your patch as-is.