+++ /dev/null
-From: =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= <toke@toke.dk>
-Date: Tue, 18 Dec 2018 17:02:06 -0800
-Subject: [PATCH] mac80211: Add TXQ scheduling API
-MIME-Version: 1.0
-Content-Type: text/plain; charset=UTF-8
-Content-Transfer-Encoding: 8bit
-
-This adds an API to mac80211 to handle scheduling of TXQs. The interface
-between driver and mac80211 for TXQ handling is changed by adding two new
-functions: ieee80211_next_txq(), which will return the next TXQ to schedule
-in the current round-robin rotation, and ieee80211_return_txq(), which the
-driver uses to indicate that it has finished scheduling a TXQ (which will
-then be put back in the scheduling rotation if it isn't empty).
-
-The driver must call ieee80211_txq_schedule_start() at the start of each
-scheduling session, and ieee80211_txq_schedule_end() at the end. The API
-then guarantees that the same TXQ is not returned twice in the same
-session (so a driver can loop on ieee80211_next_txq() without worrying
-about breaking the loop.
-
-Usage of the new API is optional, so drivers can be ported one at a time.
-In this patch, the actual scheduling performed by mac80211 is simple
-round-robin, but a subsequent commit adds airtime fairness awareness to the
-scheduler.
-
-Signed-off-by: Toke Høiland-Jørgensen <toke@toke.dk>
-[minor kernel-doc fix, propagate sparse locking checks out]
-Signed-off-by: Johannes Berg <johannes.berg@intel.com>
----
-
---- a/include/net/mac80211.h
-+++ b/include/net/mac80211.h
-@@ -107,9 +107,15 @@
- * 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 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.
-+ *
-+ * Drivers can optionally delegate responsibility for scheduling queues to
-+ * mac80211, to take advantage of airtime fairness accounting. In this case, to
-+ * obtain the next queue to pull frames from, the driver calls
-+ * ieee80211_next_txq(). The driver is then expected to return the txq using
-+ * ieee80211_return_txq().
- *
- * For AP powersave TIM handling, the driver only needs to indicate if it has
- * buffered packets in the driver specific data structures by calling
-@@ -5979,7 +5985,8 @@ void ieee80211_unreserve_tid(struct ieee
- * 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 station or virtual interface, or from
-+ * ieee80211_next_txq()
- *
- * Returns the skb if successful, %NULL if no frame was available.
- */
-@@ -5987,6 +5994,54 @@ struct sk_buff *ieee80211_tx_dequeue(str
- struct ieee80211_txq *txq);
-
- /**
-+ * ieee80211_next_txq - get next tx queue to pull packets from
-+ *
-+ * @hw: pointer as obtained from ieee80211_alloc_hw()
-+ * @ac: AC number to return packets from.
-+ *
-+ * Should only be called between calls to ieee80211_txq_schedule_start()
-+ * and ieee80211_txq_schedule_end().
-+ * Returns the next txq if successful, %NULL if no queue is eligible. If a txq
-+ * is returned, it should be returned with ieee80211_return_txq() after the
-+ * driver has finished scheduling it.
-+ */
-+struct ieee80211_txq *ieee80211_next_txq(struct ieee80211_hw *hw, u8 ac);
-+
-+/**
-+ * ieee80211_return_txq - return a TXQ previously acquired by ieee80211_next_txq()
-+ *
-+ * @hw: pointer as obtained from ieee80211_alloc_hw()
-+ * @txq: pointer obtained from station or virtual interface
-+ *
-+ * Should only be called between calls to ieee80211_txq_schedule_start()
-+ * and ieee80211_txq_schedule_end().
-+ */
-+void ieee80211_return_txq(struct ieee80211_hw *hw, struct ieee80211_txq *txq);
-+
-+/**
-+ * ieee80211_txq_schedule_start - acquire locks for safe scheduling of an AC
-+ *
-+ * @hw: pointer as obtained from ieee80211_alloc_hw()
-+ * @ac: AC number to acquire locks for
-+ *
-+ * Acquire locks needed to schedule TXQs from the given AC. Should be called
-+ * before ieee80211_next_txq() or ieee80211_return_txq().
-+ */
-+void ieee80211_txq_schedule_start(struct ieee80211_hw *hw, u8 ac)
-+ __acquires(txq_lock);
-+
-+/**
-+ * ieee80211_txq_schedule_end - release locks for safe scheduling of an AC
-+ *
-+ * @hw: pointer as obtained from ieee80211_alloc_hw()
-+ * @ac: AC number to acquire locks for
-+ *
-+ * Release locks previously acquired by ieee80211_txq_schedule_end().
-+ */
-+void ieee80211_txq_schedule_end(struct ieee80211_hw *hw, u8 ac)
-+ __releases(txq_lock);
-+
-+/**
- * 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.
---- a/net/mac80211/agg-tx.c
-+++ b/net/mac80211/agg-tx.c
-@@ -229,7 +229,7 @@ ieee80211_agg_start_txq(struct sta_info
- clear_bit(IEEE80211_TXQ_STOP, &txqi->flags);
- local_bh_disable();
- rcu_read_lock();
-- drv_wake_tx_queue(sta->sdata->local, txqi);
-+ schedule_and_wake_txq(sta->sdata->local, txqi);
- rcu_read_unlock();
- local_bh_enable();
- }
---- a/net/mac80211/driver-ops.h
-+++ b/net/mac80211/driver-ops.h
-@@ -1176,6 +1176,15 @@ static inline void drv_wake_tx_queue(str
- local->ops->wake_tx_queue(&local->hw, &txq->txq);
- }
-
-+static inline void schedule_and_wake_txq(struct ieee80211_local *local,
-+ struct txq_info *txqi)
-+{
-+ spin_lock_bh(&local->active_txq_lock[txqi->txq.ac]);
-+ ieee80211_return_txq(&local->hw, &txqi->txq);
-+ spin_unlock_bh(&local->active_txq_lock[txqi->txq.ac]);
-+ drv_wake_tx_queue(local, txqi);
-+}
-+
- static inline int drv_start_nan(struct ieee80211_local *local,
- struct ieee80211_sub_if_data *sdata,
- struct cfg80211_nan_conf *conf)
---- a/net/mac80211/ieee80211_i.h
-+++ b/net/mac80211/ieee80211_i.h
-@@ -829,6 +829,8 @@ enum txq_info_flags {
- * a fq_flow which is already owned by a different tin
- * @def_cvars: codel vars for @def_flow
- * @frags: used to keep fragments created after dequeue
-+ * @schedule_order: used with ieee80211_local->active_txqs
-+ * @schedule_round: counter to prevent infinite loops on TXQ scheduling
- */
- struct txq_info {
- struct fq_tin tin;
-@@ -836,6 +838,8 @@ struct txq_info {
- struct codel_vars def_cvars;
- struct codel_stats cstats;
- struct sk_buff_head frags;
-+ struct list_head schedule_order;
-+ u16 schedule_round;
- unsigned long flags;
-
- /* keep last! */
-@@ -1127,6 +1131,11 @@ struct ieee80211_local {
- struct codel_vars *cvars;
- struct codel_params cparams;
-
-+ /* protects active_txqs and txqi->schedule_order */
-+ spinlock_t active_txq_lock[IEEE80211_NUM_ACS];
-+ struct list_head active_txqs[IEEE80211_NUM_ACS];
-+ u16 schedule_round[IEEE80211_NUM_ACS];
-+
- const struct ieee80211_ops *ops;
-
- /*
---- a/net/mac80211/main.c
-+++ b/net/mac80211/main.c
-@@ -652,6 +652,11 @@ struct ieee80211_hw *ieee80211_alloc_hw_
- spin_lock_init(&local->rx_path_lock);
- spin_lock_init(&local->queue_stop_reason_lock);
-
-+ for (i = 0; i < IEEE80211_NUM_ACS; i++) {
-+ INIT_LIST_HEAD(&local->active_txqs[i]);
-+ spin_lock_init(&local->active_txq_lock[i]);
-+ }
-+
- INIT_LIST_HEAD(&local->chanctx_list);
- mutex_init(&local->chanctx_mtx);
-
---- a/net/mac80211/sta_info.c
-+++ b/net/mac80211/sta_info.c
-@@ -1244,7 +1244,7 @@ void ieee80211_sta_ps_deliver_wakeup(str
- if (!txq_has_queue(sta->sta.txq[i]))
- continue;
-
-- drv_wake_tx_queue(local, to_txq_info(sta->sta.txq[i]));
-+ schedule_and_wake_txq(local, to_txq_info(sta->sta.txq[i]));
- }
- }
-
---- a/net/mac80211/tx.c
-+++ b/net/mac80211/tx.c
-@@ -1441,6 +1441,7 @@ void ieee80211_txq_init(struct ieee80211
- codel_vars_init(&txqi->def_cvars);
- codel_stats_init(&txqi->cstats);
- __skb_queue_head_init(&txqi->frags);
-+ INIT_LIST_HEAD(&txqi->schedule_order);
-
- txqi->txq.vif = &sdata->vif;
-
-@@ -1464,6 +1465,9 @@ void ieee80211_txq_purge(struct ieee8021
-
- fq_tin_reset(fq, tin, fq_skb_free_func);
- ieee80211_purge_tx_queue(&local->hw, &txqi->frags);
-+ spin_lock_bh(&local->active_txq_lock[txqi->txq.ac]);
-+ list_del_init(&txqi->schedule_order);
-+ spin_unlock_bh(&local->active_txq_lock[txqi->txq.ac]);
- }
-
- void ieee80211_txq_set_params(struct ieee80211_local *local)
-@@ -1580,7 +1584,7 @@ static bool ieee80211_queue_skb(struct i
- ieee80211_txq_enqueue(local, txqi, skb);
- spin_unlock_bh(&fq->lock);
-
-- drv_wake_tx_queue(local, txqi);
-+ schedule_and_wake_txq(local, txqi);
-
- return true;
- }
-@@ -3602,6 +3606,60 @@ out:
- }
- EXPORT_SYMBOL(ieee80211_tx_dequeue);
-
-+struct ieee80211_txq *ieee80211_next_txq(struct ieee80211_hw *hw, u8 ac)
-+{
-+ struct ieee80211_local *local = hw_to_local(hw);
-+ struct txq_info *txqi = NULL;
-+
-+ lockdep_assert_held(&local->active_txq_lock[ac]);
-+
-+ txqi = list_first_entry_or_null(&local->active_txqs[ac],
-+ struct txq_info,
-+ schedule_order);
-+
-+ if (!txqi || txqi->schedule_round == local->schedule_round[ac])
-+ return NULL;
-+
-+ list_del_init(&txqi->schedule_order);
-+ txqi->schedule_round = local->schedule_round[ac];
-+ return &txqi->txq;
-+}
-+EXPORT_SYMBOL(ieee80211_next_txq);
-+
-+void ieee80211_return_txq(struct ieee80211_hw *hw,
-+ struct ieee80211_txq *txq)
-+{
-+ struct ieee80211_local *local = hw_to_local(hw);
-+ struct txq_info *txqi = to_txq_info(txq);
-+
-+ lockdep_assert_held(&local->active_txq_lock[txq->ac]);
-+
-+ if (list_empty(&txqi->schedule_order) &&
-+ (!skb_queue_empty(&txqi->frags) || txqi->tin.backlog_packets))
-+ list_add_tail(&txqi->schedule_order,
-+ &local->active_txqs[txq->ac]);
-+}
-+EXPORT_SYMBOL(ieee80211_return_txq);
-+
-+void ieee80211_txq_schedule_start(struct ieee80211_hw *hw, u8 ac)
-+ __acquires(txq_lock)
-+{
-+ struct ieee80211_local *local = hw_to_local(hw);
-+
-+ spin_lock_bh(&local->active_txq_lock[ac]);
-+ local->schedule_round[ac]++;
-+}
-+EXPORT_SYMBOL(ieee80211_txq_schedule_start);
-+
-+void ieee80211_txq_schedule_end(struct ieee80211_hw *hw, u8 ac)
-+ __releases(txq_lock)
-+{
-+ struct ieee80211_local *local = hw_to_local(hw);
-+
-+ spin_unlock_bh(&local->active_txq_lock[ac]);
-+}
-+EXPORT_SYMBOL(ieee80211_txq_schedule_end);
-+
- void __ieee80211_subif_start_xmit(struct sk_buff *skb,
- struct net_device *dev,
- u32 info_flags)
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