mac80211: add functions to stop and wake all queues assigned to a vif

In some cases we may want to stop the queues of a single vif (for
instance during a channel-switch).  Add a function that stops all the
queues that are assigned to a vif.  If a queue is assigned to more
than one vif, the corresponding netdev subqueue of the other vif(s)
will also be stopped.  If the HW doesn't set the
IEEE80211_HW_QUEUE_CONTROL flag, then all queues are stopped.

Also add a corresponding function to wake the queues of a vif back.
Signed-off-by: Luciano Coelho <luciano.coelho@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/ieee80211_i.h

@@ -1720,6 +1720,12 @@ void ieee80211_wake_queues_by_reason(struct ieee80211_hw *hw,
 				     unsigned long queues,
 				     enum queue_stop_reason reason,
 				     bool refcounted);
+void ieee80211_stop_vif_queues(struct ieee80211_local *local,
+			       struct ieee80211_sub_if_data *sdata,
+			       enum queue_stop_reason reason);
+void ieee80211_wake_vif_queues(struct ieee80211_local *local,
+			       struct ieee80211_sub_if_data *sdata,
+			       enum queue_stop_reason reason);
 void ieee80211_stop_queues_by_reason(struct ieee80211_hw *hw,
 				     unsigned long queues,
 				     enum queue_stop_reason reason,

net/mac80211/util.c

@@ -552,13 +552,11 @@ void ieee80211_wake_queues(struct ieee80211_hw *hw)
 }
 EXPORT_SYMBOL(ieee80211_wake_queues);
 
-void ieee80211_flush_queues(struct ieee80211_local *local,
-			    struct ieee80211_sub_if_data *sdata)
+static unsigned int
+ieee80211_get_vif_queues(struct ieee80211_local *local,
+			 struct ieee80211_sub_if_data *sdata)
 {
-	u32 queues;
-
-	if (!local->ops->flush)
-		return;
+	unsigned int queues;
 
 	if (sdata && local->hw.flags & IEEE80211_HW_QUEUE_CONTROL) {
 		int ac;
@@ -574,6 +572,19 @@ void ieee80211_flush_queues(struct ieee80211_local *local,
 		queues = BIT(local->hw.queues) - 1;
 	}
 
+	return queues;
+}
+
+void ieee80211_flush_queues(struct ieee80211_local *local,
+			    struct ieee80211_sub_if_data *sdata)
+{
+	unsigned int queues;
+
+	if (!local->ops->flush)
+		return;
+
+	queues = ieee80211_get_vif_queues(local, sdata);
+
 	ieee80211_stop_queues_by_reason(&local->hw, queues,
 					IEEE80211_QUEUE_STOP_REASON_FLUSH,
 					false);
@@ -585,6 +596,24 @@ void ieee80211_flush_queues(struct ieee80211_local *local,
 					false);
 }
 
+void ieee80211_stop_vif_queues(struct ieee80211_local *local,
+			       struct ieee80211_sub_if_data *sdata,
+			       enum queue_stop_reason reason)
+{
+	ieee80211_stop_queues_by_reason(&local->hw,
+					ieee80211_get_vif_queues(local, sdata),
+					reason, true);
+}
+
+void ieee80211_wake_vif_queues(struct ieee80211_local *local,
+			       struct ieee80211_sub_if_data *sdata,
+			       enum queue_stop_reason reason)
+{
+	ieee80211_wake_queues_by_reason(&local->hw,
+					ieee80211_get_vif_queues(local, sdata),
+					reason, true);
+}
+
 static void __iterate_active_interfaces(struct ieee80211_local *local,
 					u32 iter_flags,
 					void (*iterator)(void *data, u8 *mac,