crash when connecting to targets using nr_io_queues < num cpus

[Steve Wise]

> 
> > Hey all,
> >
> > I'm testing smaller ioq sets with nvmf/rdma, and I see some issue.  If I
connect
> > with 2, 4, 6, 8, 10, 16, or 32  for nr_io_queues, everything is happy.  It
> > seems, though, if I connect with a value of 12, or 28, or some other non
power
> > of two, I get intermittent crashes in __blk_mq_get_reserved_tag() at line
337
> > when setting up a controller's IO queues.   I'm not sure exactly if this is
> > always non power of two, or something else, but it seems to never crash with
> > power of two values (could be a coincidence I guess).
> 
> I think Ming sent a patch for this some time ago... Not sure what
> happened with it though...

This?

http://lists.infradead.org/pipermail/linux-nvme/2016-June/004884.html