mac80211: allow the driver not to pass the tid to ieee80211_sta_uapsd_trigger

iwlwifi will check internally that the tid maps to an AC
that is trigger enabled, but can't know what tid exactly.
Allow the driver to pass a generic tid and make mac80211
assume that a trigger frame was received.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

include/net/mac80211.h

@@ -4087,6 +4087,10 @@ void ieee80211_sta_pspoll(struct ieee80211_sta *sta);
  * This must be used in conjunction with ieee80211_sta_ps_transition()
  * and possibly ieee80211_sta_pspoll(); calls to all three must be
  * serialized.
+ * %IEEE80211_NUM_TIDS can be passed as the tid if the tid is unknown.
+ * In this case, mac80211 will not check that this tid maps to an AC
+ * that is trigger enabled and assume that the caller did the proper
+ * checks.
  */
 void ieee80211_sta_uapsd_trigger(struct ieee80211_sta *sta, u8 tid);
 

net/mac80211/rx.c

@@ -1394,13 +1394,14 @@ void ieee80211_sta_uapsd_trigger(struct ieee80211_sta *pubsta, u8 tid)
 	u8 ac = ieee802_1d_to_ac[tid & 7];
 
 	/*
-	 * If this AC is not trigger-enabled do nothing.
+	 * If this AC is not trigger-enabled do nothing unless the
+	 * driver is calling us after it already checked.
 	 *
 	 * NB: This could/should check a separate bitmap of trigger-
 	 * enabled queues, but for now we only implement uAPSD w/o
 	 * TSPEC changes to the ACs, so they're always the same.
 	 */
-	if (!(sta->sta.uapsd_queues & BIT(ac)))
+	if (!(sta->sta.uapsd_queues & BIT(ac)) && tid != IEEE80211_NUM_TIDS)
 		return;
 
 	/* if we are in a service period, do nothing */