converting mac80211 to TXQs entirely

[Johannes Berg <johannes@sipsolutions.net>]

Hi,

Part 1 is just a dump of my notes analysing the current TX scheme.


driver setup
============

non-QUEUE_CONTROL drivers
 * have >= 4 queues
   - per-AC queues [0-3]
 * have < 4 queues
   - all goes to queue 0

QUEUE_CONTROL drivers
 * hwsim (doesn't handle CAB correctly)
   - each vif: 0...3
   - each cab: 0
   - offchannel: 4
 * TI (doesn't set HOST_BROADCAST_PS_BUFFERING)
   - each vif: 4 queues (separate)
   - each cab: separate queue
   - offchannel: separate from all others
 * iwldvm/iwlmvm (doesn't set HOST_BROADCAST_PS_BUFFERING)
   - each vif: 4 queues (separate)
   - each cab: separate queue
   - offchannel: separate from all others (AUX)
 * ath9k (uses TXQ, sets HOST_BROADCAST_PS_BUFFERING)
   - each vif: 4 queues (shared based on chanctx)
   - each cab: all the same (# queues - 2)
   - offchannel: separate from all others
 * ath10k (may use TXQ, doesn't set HOST_BROADCAST_PS_BUFFERING)
   - each vif: 1 queue for all ACs
   - each cab: same queue as for ACs
   - offchannel: separate from all others


current TX scheme
=================
HOST_BROADCAST_PS_BUFFERING && IEEE80211_TX_CTL_SEND_AFTER_DTIM
 --> queue for ieee80211_get_buffered_bc()

!AP_LINK_PS && sta sleeping
 --> queue on sta->ps_tx_buf[ac] for wakeup/poll
 --> send on poll with IEEE80211_TX_CTRL_PS_RESPONSE
 --> send on wakeup as normal frame (with or without TXQ)
     [NB: with TXQs, this is buggy due to waking old TXQ before tx_filtered]

finally
 --> send directly (with or without TXQ)

if filtered TX status
 --> append to tx_filtered[ac] and use that before ps_tx_buf[ac]

TXQ scheme (where used)
=======================

MONITOR || IEEE80211_TX_CTL_SEND_AFTER_DTIM || IEEE80211_TX_CTRL_PS_RESPONSE || non-data
 --> send directly (to TX queue number as given above)
have STA
 --> per-STA/TID TXQ
otherwise
 --> per-VIF TXQ (for VLAN use AP instead)