[PATCH v3 2/9] nvme-fabrics: allow to queue requests for live queues

[Sagi Grimberg]

>> I still dislike any random ioctls coming in while we're still initializing
>> the controller.
> 
> Agreed.
> 
>>    Looking at the flow - I wouldn't want them to be allowed
>> until after nvme_init_identify() is complete. Especially if the ioctls are
>> doing subsystem or controller dumping or using commands that should be
>> capped by values set by nvme_queue_limits().   But, if we're going to
>> allow nvme_init_identify the admin_q needs to be unquiesced.
>>
>> So I'm still voting for the admin queue exception.
> 
> And I really don't like the admin queue special case.  What is the
> advantage of letting user space passthrough I/O commands in at this
> point in time?

We need to pass in normal I/O commands for sure in order to have a
robust reset and error recovery (what in general the patchset
addresses). What is the difference between FS I/O commands and
passthru I/O commands? In fact, user passthru I/O commands will never
execute before nvme_init_identify() because we always start
the I/O queues after that.

Let's look at pci, do we have the same enforcement for passthru
commands? What's special about fabrics that we need to deny
these commands from going through?