UNDI may need to block multi-threaded/multi-processor access to
critical code sections when programming or accessing the network
device. To this end, a blocking service is needed by the UNDI.
When UNDI needs a block, it will call Block() passing a non-zero
value. When UNDI no longer needs a block, it will call Block()
with a zero value. When called, if the Block() is already enabled,
do not return control to the UNDI until the previous Block() is
disabled.
PXE_VOID Block(UINT64 unq_id, UINT32 enable);
UNDI may need to block multi-threaded/multi-processor access to critical code sections when programming or accessing the network device. To this end, a blocking service is needed by the UNDI. When UNDI needs a block, it will call Block() passing a non-zero value. When UNDI no longer needs a block, it will call Block() with a zero value. When called, if the Block() is already enabled, do not return control to the UNDI until the previous Block() is disabled.
This field cannot be set to zero.