 - Synchronize access to the swdevt's sw_blist with sw_dev_mtx.  - Remove several instances of GIANT_REQUIRED.
 - Synchronize access to the swdevt's sw_blist with sw_dev_mtx.
 - Remove several instances of GIANT_REQUIRED.

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