MFC: expand critical section coverage so that shared fast and ithread handlers don't stall.
MFC: expand critical section coverage so that shared fast and ithread handlers
don't stall.

Approved by: re

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