Implement the protection check required by the pmap_extract_and_hold() specification.  This enables the elimination of Giant from that function.
Implement the protection check required by the pmap_extract_and_hold()
specification.  This enables the elimination of Giant from that function.

Reviewed by:	tegge@

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