Lock-free tdb lookups

[Joe Seigh]

I took a look at the tdb source.  It would be pretty straightforward
to make it read lock-free except for the transactional stuff.
Transactions have to be atomic w.r.t. other operations.  I can't see
any way of making things lock-free without infringing, in part at least,
on patent application 20050198030 "Efficient support of consistent cyclic
search with read-copy-update" by Paul McKenney, file in March 2004,
and probably on anything else filed on software transactional memory.

So "Closed on account of patents" I guess.

--
Joe Seigh