mac80211: Add airtime account and scheduling to TXQs

This adds airtime accounting and scheduling to the mac80211 TXQ
scheduler. A new hardware flag, AIRTIME_ACCOUNTING, is added that
drivers can set if they support reporting airtime usage of
transmissions. When this flag is set, mac80211 will expect the actual
airtime usage to be reported in the tx_time and rx_time fields of the
respective status structs.

When airtime information is present, mac80211 will schedule TXQs
(through ieee80211_next_txq()) in a way that enforces airtime fairness
between active stations. This scheduling works the same way as the ath9k
in-driver airtime fairness scheduling.

Signed-off-by: Toke Høiland-Jørgensen <toke@toke.dk>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 6 insertions, 2 deletions

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 4155838c7bef..120c516851cf 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -90,6 +90,9 @@ extern const u8 ieee80211_ac_to_qos_mask[IEEE80211_NUM_ACS];
 
 #define IEEE80211_MAX_NAN_INSTANCE_ID 255
 
+/* How much to increase airtime deficit on each scheduling round */
+#define IEEE80211_AIRTIME_QUANTUM        1000 /* usec */
+
 struct ieee80211_fragment_entry {
 	struct sk_buff_head skb_list;
 	unsigned long first_frag_time;
@@ -1123,9 +1126,10 @@ struct ieee80211_local {
 	struct codel_vars *cvars;
 	struct codel_params cparams;
 
-	/* protects active_txqs and txqi->schedule_order */
+	/* protects active_txqs_{new,old} and txqi->schedule_order */
 	spinlock_t active_txq_lock;
-	struct list_head active_txqs;
+	struct list_head active_txqs_new;
+	struct list_head active_txqs_old;
 
 	const struct ieee80211_ops *ops;