Further tweak the changes made in r233709.  The kernel doesn't permit sleeping from a swi handler (even though in this case it would be ok), so switch the refill and scanning SWI handlers to being tasks on a fast taskqueue.  Also, only schedule the refill task for a CMCI as an MC# can fire at any time, so it should do the minimal amount of work needed and avoid opportunities to deadlock before it panics (such as scheduling a task it won't ever need in practice).  To handle the case of an MC# only finding recoverable errors (which should never happen), always try to refill the event free list when the periodic scan executes.
Further tweak the changes made in r233709.  The kernel doesn't permit
sleeping from a swi handler (even though in this case it would be ok), so
switch the refill and scanning SWI handlers to being tasks on a fast
taskqueue.  Also, only schedule the refill task for a CMCI as an MC# can
fire at any time, so it should do the minimal amount of work needed and
avoid opportunities to deadlock before it panics (such as scheduling a
task it won't ever need in practice).  To handle the case of an MC# only
finding recoverable errors (which should never happen), always try to
refill the event free list when the periodic scan executes.

MFC after:	2 weeks

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase