mac80211: track master queue status

This is a preparation for the dynamic power save support. In future there are
two paths to stop the master queues and we need to track this properly to
avoid starting queues incorrectly. Implement this by adding a status
array for each queue.

The original idea and design is from Johannes Berg, I just did
the implementation based on his notes. All the bugs are mine, of course.

Signed-off-by: Kalle Valo <kalle.valo@nokia.com>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 18b9160..a74d673 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -538,6 +538,10 @@
 	IEEE80211_ADDBA_MSG	= 4,
 };
 
+enum queue_stop_reason {
+	IEEE80211_QUEUE_STOP_REASON_DRIVER,
+};
+
 /* maximum number of hardware queues we support. */
 #define QD_MAX_QUEUES (IEEE80211_MAX_AMPDU_QUEUES + IEEE80211_MAX_QUEUES)
 
@@ -554,7 +558,8 @@
 	const struct ieee80211_ops *ops;
 
 	unsigned long queue_pool[BITS_TO_LONGS(QD_MAX_QUEUES)];
-
+	unsigned long queue_stop_reasons[IEEE80211_MAX_QUEUES];
+	spinlock_t queue_stop_reason_lock;
 	struct net_device *mdev; /* wmaster# - "master" 802.11 device */
 	int open_count;
 	int monitors, cooked_mntrs;
@@ -972,6 +977,11 @@
 u64 ieee80211_mandatory_rates(struct ieee80211_local *local,
 			      enum ieee80211_band band);
 
+void ieee80211_wake_queues_by_reason(struct ieee80211_hw *hw,
+				     enum queue_stop_reason reason);
+void ieee80211_stop_queues_by_reason(struct ieee80211_hw *hw,
+				     enum queue_stop_reason reason);
+
 #ifdef CONFIG_MAC80211_NOINLINE
 #define debug_noinline noinline
 #else
diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index ab6b736..2133538 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -725,6 +725,8 @@
 
 	spin_lock_init(&local->key_lock);
 
+	spin_lock_init(&local->queue_stop_reason_lock);
+
 	INIT_DELAYED_WORK(&local->scan_work, ieee80211_scan_work);
 
 	sta_info_init(local);
diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index 71a8391..fb89e1d 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -330,10 +330,20 @@
 }
 EXPORT_SYMBOL(ieee80211_ctstoself_duration);
 
-void ieee80211_wake_queue(struct ieee80211_hw *hw, int queue)
+static void __ieee80211_wake_queue(struct ieee80211_hw *hw, int queue,
+				   enum queue_stop_reason reason)
 {
 	struct ieee80211_local *local = hw_to_local(hw);
 
+	/* we don't need to track ampdu queues */
+	if (queue < ieee80211_num_regular_queues(hw)) {
+		__clear_bit(reason, &local->queue_stop_reasons[queue]);
+
+		if (local->queue_stop_reasons[queue] != 0)
+			/* someone still has this queue stopped */
+			return;
+	}
+
 	if (test_bit(queue, local->queues_pending)) {
 		set_bit(queue, local->queues_pending_run);
 		tasklet_schedule(&local->tx_pending_tasklet);
@@ -341,22 +351,74 @@
 		netif_wake_subqueue(local->mdev, queue);
 	}
 }
+
+void ieee80211_wake_queue_by_reason(struct ieee80211_hw *hw, int queue,
+				    enum queue_stop_reason reason)
+{
+	struct ieee80211_local *local = hw_to_local(hw);
+	unsigned long flags;
+
+	spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
+	__ieee80211_wake_queue(hw, queue, reason);
+	spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);
+}
+
+void ieee80211_wake_queue(struct ieee80211_hw *hw, int queue)
+{
+	ieee80211_wake_queue_by_reason(hw, queue,
+				       IEEE80211_QUEUE_STOP_REASON_DRIVER);
+}
 EXPORT_SYMBOL(ieee80211_wake_queue);
 
-void ieee80211_stop_queue(struct ieee80211_hw *hw, int queue)
+static void __ieee80211_stop_queue(struct ieee80211_hw *hw, int queue,
+				   enum queue_stop_reason reason)
 {
 	struct ieee80211_local *local = hw_to_local(hw);
 
+	/* we don't need to track ampdu queues */
+	if (queue < ieee80211_num_regular_queues(hw))
+		__set_bit(reason, &local->queue_stop_reasons[queue]);
+
 	netif_stop_subqueue(local->mdev, queue);
 }
+
+void ieee80211_stop_queue_by_reason(struct ieee80211_hw *hw, int queue,
+				    enum queue_stop_reason reason)
+{
+	struct ieee80211_local *local = hw_to_local(hw);
+	unsigned long flags;
+
+	spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
+	__ieee80211_stop_queue(hw, queue, reason);
+	spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);
+}
+
+void ieee80211_stop_queue(struct ieee80211_hw *hw, int queue)
+{
+	ieee80211_stop_queue_by_reason(hw, queue,
+				       IEEE80211_QUEUE_STOP_REASON_DRIVER);
+}
 EXPORT_SYMBOL(ieee80211_stop_queue);
 
-void ieee80211_stop_queues(struct ieee80211_hw *hw)
+void ieee80211_stop_queues_by_reason(struct ieee80211_hw *hw,
+				    enum queue_stop_reason reason)
 {
+	struct ieee80211_local *local = hw_to_local(hw);
+	unsigned long flags;
 	int i;
 
+	spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
+
 	for (i = 0; i < ieee80211_num_queues(hw); i++)
-		ieee80211_stop_queue(hw, i);
+		__ieee80211_stop_queue(hw, i, reason);
+
+	spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);
+}
+
+void ieee80211_stop_queues(struct ieee80211_hw *hw)
+{
+	ieee80211_stop_queues_by_reason(hw,
+					IEEE80211_QUEUE_STOP_REASON_DRIVER);
 }
 EXPORT_SYMBOL(ieee80211_stop_queues);
 
@@ -367,12 +429,24 @@
 }
 EXPORT_SYMBOL(ieee80211_queue_stopped);
 
-void ieee80211_wake_queues(struct ieee80211_hw *hw)
+void ieee80211_wake_queues_by_reason(struct ieee80211_hw *hw,
+				     enum queue_stop_reason reason)
 {
+	struct ieee80211_local *local = hw_to_local(hw);
+	unsigned long flags;
 	int i;
 
+	spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
+
 	for (i = 0; i < hw->queues + hw->ampdu_queues; i++)
-		ieee80211_wake_queue(hw, i);
+		__ieee80211_wake_queue(hw, i, reason);
+
+	spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);
+}
+
+void ieee80211_wake_queues(struct ieee80211_hw *hw)
+{
+	ieee80211_wake_queues_by_reason(hw, IEEE80211_QUEUE_STOP_REASON_DRIVER);
 }
 EXPORT_SYMBOL(ieee80211_wake_queues);