Re: [PATCH v7 08/14] nvmet-core: allow one host per passthru-ctrl

[Sagi Grimberg]

> > > I don't understand why we don't limit a regular ctrl to single access 
> > > and we do it for the PT ctrl.
> > >
> > > I guess the block layer helps to sync between multiple access in 
> > > parallel but we can do it as well.
> > >
> > > Also, let's say you limit the access to this subsystem to 1 user, the 
> > > bdev is still accessibly for local user and also you can create a 
> > > different subsystem that will use this device (PT and non-PT ctrl).
> > >
> > > Sagi,
> > >
> > > can you explain the trouble you meant and how this limitation solve it ?
> >
> > Its different to emulate the controller with all its admin
> > commands vs. passing it through to the nvme device.. (think of format 
> > nvm)
> we don't need to support format command for PT ctrl as we don't support 
> other commands such create_sq/cq.

That is just an example, basically every command that we are not aware
of we simply passthru to the drive without knowing the implications
on a multi-host environment..