mitigate against mpii device attachment racing with mountroot

mpii devices get attached by processing sas discovery events after
threads are running, but if you have a lean (in terms of devices)
and fast machine, these events might run after mountroot.

this change has mpii use config_pending_incr() before it attaches
scsibus, and runs config_pending_decr() after the first scan of the
bus is complete.

to make sure config_pending_decr() is run after the scsi attach/detach
events are processed, the MPII_EVENT_SAS_DISCOVERY events are
deferred to the same context that the MPII_EVENT_SAS_TOPOLOGY_CHANGE_LIST
events run in.

ok jmatthew@

0 files changed, 0 insertions, 0 deletions