nvme-tcp: kernel NULL pointer dereference, address: 0000000000000034

[Sagi Grimberg]

>> The admin tagset does not have a polled hctxs map to begin with,
>> so I'm unclear how any fabrics or admin requests end up polled...
> 
> Hmm, if no map_queues() callback is provided for the admin tag set, isn't the
> default mapping function used and this would add the poll hctxs map? Let me add
> a map_queues() callback and see what happens :)

admin_tagset.nr_maps = 1 (only the default map, no read, no poll)