illumos gate

Want to integrate the one outstanding bugfix in the SmartOS tree for mpt_sas that hasn't made it upstream.

The relevant commit can be found at https://github.com/joyent/illumos-joyent/commit/d8b8daca0baacf10f4535dddb56338d0afc3b335; I'll try to ask il-dev to review a (basically unmodified) respin of the patch against il-gate HEAD, and then kick it off for RTI.

To verbatim copy from its bug report (in the event that one of these becomes unavailable before the other):

From Zhiwen Zhang:

> The scenario may be the following:
> 
> During mptsas_restart_ioc(), we already hold mpt->m_mutex and
> mpt->m_in_reset set to TRUE,
> so new commands cannot be added to active queue and wait queue, but can be
> added to tx wait queue,
> which does not require to hold mpt->m_mutex to be manipulated. So during
> ioc restart, the mptsas_target_t s
> can still be actively used, e.g. cmd->cmd_tgt_addr = ptgt in
> mptsas_scsi_init_pkt().

The IOC reset path does not need to replace the refhash. In addition to causing a memory leak, this approach leads to potential hangs in the case described above. Instead, we should allocate this once in the attach path and then leave it alone.