mac80211: Add TXQ scheduling API

This adds an API to mac80211 to handle scheduling of TXQs and changes the
interface between driver and mac80211 for TXQ handling as follows:

- The wake_tx_queue callback interface no longer includes the TXQ. Instead,
  the driver is expected to retrieve that from ieee80211_next_txq()

- Two new mac80211 functions are added: ieee80211_next_txq() and
  ieee80211_schedule_txq(). The former returns the next TXQ that should be
  scheduled, and is how the driver gets a queue to pull packets from. The
  latter is called internally by mac80211 to start scheduling a queue, and
  the driver is supposed to call it to re-schedule the TXQ after it is
  finished pulling packets from it (unless the queue emptied).

The ath9k and ath10k drivers are changed to use the new API.

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

1 files changed, 31 insertions, 6 deletions

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 906e90223066..45155803c875 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -105,9 +105,12 @@
  * The driver is expected to initialize its private per-queue data for stations
  * and interfaces in the .add_interface and .sta_add ops.
  *
- * The driver can't access the queue directly. To dequeue a frame, it calls
- * ieee80211_tx_dequeue(). Whenever mac80211 adds a new frame to a queue, it
- * calls the .wake_tx_queue driver op.
+ * The driver can't access the queue directly. To obtain the next queue to pull
+ * frames from, the driver calls ieee80211_next_txq(). To dequeue a frame from a
+ * txq, it calls ieee80211_tx_dequeue(). Whenever mac80211 adds a new frame to a
+ * queue, it calls the .wake_tx_queue driver op. The driver is expected to
+ * re-schedule the txq using ieee80211_schedule_txq() if it is still active
+ * after the driver has finished pulling packets from it.
  *
  * For AP powersave TIM handling, the driver only needs to indicate if it has
  * buffered packets in the driver specific data structures by calling
@@ -3731,8 +3734,7 @@ struct ieee80211_ops {
 					 struct ieee80211_vif *vif,
 					 struct ieee80211_tdls_ch_sw_params *params);
 
-	void (*wake_tx_queue)(struct ieee80211_hw *hw,
-			      struct ieee80211_txq *txq);
+	void (*wake_tx_queue)(struct ieee80211_hw *hw);
 	void (*sync_rx_queues)(struct ieee80211_hw *hw);
 
 	int (*start_nan)(struct ieee80211_hw *hw,
@@ -5883,7 +5885,7 @@ void ieee80211_unreserve_tid(struct ieee80211_sta *sta, u8 tid);
  * ieee80211_tx_dequeue - dequeue a packet from a software tx queue
  *
  * @hw: pointer as obtained from ieee80211_alloc_hw()
- * @txq: pointer obtained from station or virtual interface
+ * @txq: pointer obtained from ieee80211_next_txq()
  *
  * Returns the skb if successful, %NULL if no frame was available.
  */
@@ -5891,6 +5893,29 @@ struct sk_buff *ieee80211_tx_dequeue(struct ieee80211_hw *hw,
 				     struct ieee80211_txq *txq);
 
 /**
+ * ieee80211_schedule_txq - add txq to scheduling loop
+ *
+ * @hw: pointer as obtained from ieee80211_alloc_hw()
+ * @txq: pointer obtained from station or virtual interface
+ *
+ * Returns %true if the txq was actually added to the scheduling,
+ * %false otherwise.
+ */
+bool ieee80211_schedule_txq(struct ieee80211_hw *hw,
+			    struct ieee80211_txq *txq);
+
+/**
+ * ieee80211_next_txq - get next tx queue to pull packets from
+ *
+ * @hw: pointer as obtained from ieee80211_alloc_hw()
+ *
+ * Returns the next txq if successful, %NULL if no queue is eligible. If a txq
+ * is returned, it will have been removed from the scheduler queue and needs to
+ * be re-scheduled with ieee80211_schedule_txq() to continue to be active.
+ */
+struct ieee80211_txq *ieee80211_next_txq(struct ieee80211_hw *hw);
+
+/**
  * ieee80211_txq_get_depth - get pending frame/byte count of given txq
  *
  * The values are not guaranteed to be coherent with regard to each other, i.e.