mac80211: add improved HW queue control

mac80211 currently only supports one hardware queue
per AC. This is already problematic for off-channel
uses since if we go off channel while the BE queue
is full and then try to send an off-channel frame
the frame will never go out. This will become worse
when we support multi-channel since then a queue on
one channel might be full, but we have to stop the
software queue for all channels. That is obviously
not desirable.

To address this problem allow drivers to register
more hardware queues, and allow them to map them to
virtual interfaces. When they stop a hardware queue
the corresponding AC software queues on the correct
interfaces will be stopped as well. Additionally,
there's an off-channel queue to solve that problem
and a per-interface after-DTIM beacon queue. This
allows drivers to manage software queues closer to
how the hardware works.

Currently, there's a limit of 16 hardware queues.
This may or may not be sufficient, we can adjust it
as needed.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 29 insertions, 9 deletions

diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index a8d0188ab40..4f6aac16ac3 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -400,6 +400,8 @@ ieee80211_tx_h_multicast_ps_buf(struct ieee80211_tx_data *tx)
 		return TX_CONTINUE;
 
 	info->flags |= IEEE80211_TX_CTL_SEND_AFTER_DTIM;
+	if (tx->local->hw.flags & IEEE80211_HW_QUEUE_CONTROL)
+		info->hw_queue = tx->sdata->vif.cab_queue;
 
 	/* device releases frame after DTIM beacon */
 	if (!(tx->local->hw.flags & IEEE80211_HW_HOST_BROADCAST_PS_BUFFERING))
@@ -1214,11 +1216,19 @@ static bool ieee80211_tx_frags(struct ieee80211_local *local,
 			       bool txpending)
 {
 	struct sk_buff *skb, *tmp;
-	struct ieee80211_tx_info *info;
 	unsigned long flags;
 
 	skb_queue_walk_safe(skbs, skb, tmp) {
-		int q = skb_get_queue_mapping(skb);
+		struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
+		int q = info->hw_queue;
+
+#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
+		if (WARN_ON_ONCE(q >= local->hw.queues)) {
+			__skb_unlink(skb, skbs);
+			dev_kfree_skb(skb);
+			continue;
+		}
+#endif
 
 		spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
 		if (local->queue_stop_reasons[q] ||
@@ -1240,7 +1250,6 @@ static bool ieee80211_tx_frags(struct ieee80211_local *local,
 		}
 		spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);
 
-		info = IEEE80211_SKB_CB(skb);
 		info->control.vif = vif;
 		info->control.sta = sta;
 
@@ -1284,9 +1293,14 @@ static bool __ieee80211_tx(struct ieee80211_local *local,
 	switch (sdata->vif.type) {
 	case NL80211_IFTYPE_MONITOR:
 		sdata = rcu_dereference(local->monitor_sdata);
-		if (sdata)
+		if (sdata) {
 			vif = &sdata->vif;
-		else
+			info->hw_queue =
+				vif->hw_queue[skb_get_queue_mapping(skb)];
+		} else if (local->hw.flags & IEEE80211_HW_QUEUE_CONTROL) {
+			dev_kfree_skb(skb);
+			return true;
+		} else
 			vif = NULL;
 		break;
 	case NL80211_IFTYPE_AP_VLAN:
@@ -1402,6 +1416,12 @@ static bool ieee80211_tx(struct ieee80211_sub_if_data *sdata,
 	tx.channel = local->hw.conf.channel;
 	info->band = tx.channel->band;
 
+	/* set up hw_queue value early */
+	if (!(info->flags & IEEE80211_TX_CTL_TX_OFFCHAN) ||
+	    !(local->hw.flags & IEEE80211_HW_QUEUE_CONTROL))
+		info->hw_queue =
+			sdata->vif.hw_queue[skb_get_queue_mapping(skb)];
+
 	if (!invoke_tx_handlers(&tx))
 		result = __ieee80211_tx(local, &tx.skbs, led_len,
 					tx.sta, txpending);
@@ -2172,7 +2192,6 @@ static bool ieee80211_tx_pending_skb(struct ieee80211_local *local,
 void ieee80211_tx_pending(unsigned long data)
 {
 	struct ieee80211_local *local = (struct ieee80211_local *)data;
-	struct ieee80211_sub_if_data *sdata;
 	unsigned long flags;
 	int i;
 	bool txok;
@@ -2209,8 +2228,7 @@ void ieee80211_tx_pending(unsigned long data)
 		}
 
 		if (skb_queue_empty(&local->pending[i]))
-			list_for_each_entry_rcu(sdata, &local->interfaces, list)
-				netif_wake_subqueue(sdata->dev, i);
+			ieee80211_propagate_queue_wake(local, i);
 	}
 	spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);
 
@@ -2717,11 +2735,13 @@ EXPORT_SYMBOL(ieee80211_get_buffered_bc);
 void ieee80211_tx_skb_tid(struct ieee80211_sub_if_data *sdata,
 			  struct sk_buff *skb, int tid)
 {
+	int ac = ieee802_1d_to_ac[tid];
+
 	skb_set_mac_header(skb, 0);
 	skb_set_network_header(skb, 0);
 	skb_set_transport_header(skb, 0);
 
-	skb_set_queue_mapping(skb, ieee802_1d_to_ac[tid]);
+	skb_set_queue_mapping(skb, ac);
 	skb->priority = tid;
 
 	/*