(or direct dispatch) behind the TXQ lock (which, remember, is doubling
as the TID lock too for now.)
This ensures that:
(a) the sequence number and the CCMP PN allocation is done together;
(b) overlapping transmit paths don't interleave frames, so we don't
end up with the original issue that triggered kern/166190.
Ie, that we don't end up with seqno A, B in thread 1, C, D in
thread 2, and they being queued to the software queue as "A C D B"
or similar, leading to the BAW stalls.
This has been tested:
* both STA and AP modes with INVARIANTS and WITNESS;
* TCP and UDP TX;
* both STA->AP and AP->STA.
STA is a Routerstation Pro (single CPU MIPS) and the AP is a dual-core
Centrino.
PR: kern/166190
7561cb5c8b