PCM_KEY_CONTROL_BLOCK
CmpInsertKeyHash(
  IN  PCM_KEY_HASH KeyHash,
  IN  BOOLEAN      FakeKey
  );

Routine Description:

    Adds a key hash structure to the hash table. The hash table
    will be checked to see if a duplicate entry already exists. If
    a duplicate is found, its kcb will be returned. If a duplicate is not
    found, NULL will be returned.

Arguments:

    KeyHash - Supplies the key hash structure to be added.

Return Value:

    NULL - if the supplied key has was added
    PCM_KEY_HASH - The duplicate hash entry, if one was found