[PATCH] nvme: don't call blk_mq_{,un}quiesce_tagset when ctrl->tagset is NULL

[Sagi Grimberg]

>>>    {
>>> +	if (!ctrl->tagset)
>>> +		return;
>>
>> Can this be placed in the pci code instead?
> 
> There's nothing PCIe-specific about this case.  All fabrics drivers
> support controllers with I/O queues and thus the I/O tagset, e.g.
> discovery controllers.

All the other drivers check that they have IO queues before
quiescing/unquiescing them.