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293 lines
10 KiB
Diff
293 lines
10 KiB
Diff
From: =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= <toke@toke.dk>
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Date: Tue, 18 Dec 2018 17:02:06 -0800
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Subject: [PATCH] mac80211: Add TXQ scheduling API
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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This adds an API to mac80211 to handle scheduling of TXQs. The interface
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between driver and mac80211 for TXQ handling is changed by adding two new
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functions: ieee80211_next_txq(), which will return the next TXQ to schedule
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in the current round-robin rotation, and ieee80211_return_txq(), which the
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driver uses to indicate that it has finished scheduling a TXQ (which will
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then be put back in the scheduling rotation if it isn't empty).
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The driver must call ieee80211_txq_schedule_start() at the start of each
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scheduling session, and ieee80211_txq_schedule_end() at the end. The API
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then guarantees that the same TXQ is not returned twice in the same
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session (so a driver can loop on ieee80211_next_txq() without worrying
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about breaking the loop.
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Usage of the new API is optional, so drivers can be ported one at a time.
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In this patch, the actual scheduling performed by mac80211 is simple
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round-robin, but a subsequent commit adds airtime fairness awareness to the
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scheduler.
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Signed-off-by: Toke Høiland-Jørgensen <toke@toke.dk>
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[minor kernel-doc fix, propagate sparse locking checks out]
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Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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---
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--- a/include/net/mac80211.h
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+++ b/include/net/mac80211.h
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@@ -107,9 +107,15 @@
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* The driver is expected to initialize its private per-queue data for stations
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* and interfaces in the .add_interface and .sta_add ops.
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*
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- * The driver can't access the queue directly. To dequeue a frame, it calls
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- * ieee80211_tx_dequeue(). Whenever mac80211 adds a new frame to a queue, it
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- * calls the .wake_tx_queue driver op.
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+ * The driver can't access the queue directly. To dequeue a frame from a
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+ * txq, it calls ieee80211_tx_dequeue(). Whenever mac80211 adds a new frame to a
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+ * queue, it calls the .wake_tx_queue driver op.
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+ *
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+ * Drivers can optionally delegate responsibility for scheduling queues to
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+ * mac80211, to take advantage of airtime fairness accounting. In this case, to
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+ * obtain the next queue to pull frames from, the driver calls
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+ * ieee80211_next_txq(). The driver is then expected to return the txq using
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+ * ieee80211_return_txq().
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*
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* For AP powersave TIM handling, the driver only needs to indicate if it has
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* buffered packets in the driver specific data structures by calling
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@@ -5979,7 +5985,8 @@ void ieee80211_unreserve_tid(struct ieee
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* ieee80211_tx_dequeue - dequeue a packet from a software tx queue
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*
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* @hw: pointer as obtained from ieee80211_alloc_hw()
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- * @txq: pointer obtained from station or virtual interface
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+ * @txq: pointer obtained from station or virtual interface, or from
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+ * ieee80211_next_txq()
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*
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* Returns the skb if successful, %NULL if no frame was available.
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*/
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@@ -5987,6 +5994,54 @@ struct sk_buff *ieee80211_tx_dequeue(str
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struct ieee80211_txq *txq);
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/**
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+ * ieee80211_next_txq - get next tx queue to pull packets from
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+ *
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+ * @hw: pointer as obtained from ieee80211_alloc_hw()
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+ * @ac: AC number to return packets from.
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+ *
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+ * Should only be called between calls to ieee80211_txq_schedule_start()
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+ * and ieee80211_txq_schedule_end().
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+ * Returns the next txq if successful, %NULL if no queue is eligible. If a txq
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+ * is returned, it should be returned with ieee80211_return_txq() after the
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+ * driver has finished scheduling it.
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+ */
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+struct ieee80211_txq *ieee80211_next_txq(struct ieee80211_hw *hw, u8 ac);
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+
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+/**
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+ * ieee80211_return_txq - return a TXQ previously acquired by ieee80211_next_txq()
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+ *
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+ * @hw: pointer as obtained from ieee80211_alloc_hw()
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+ * @txq: pointer obtained from station or virtual interface
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+ *
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+ * Should only be called between calls to ieee80211_txq_schedule_start()
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+ * and ieee80211_txq_schedule_end().
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+ */
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+void ieee80211_return_txq(struct ieee80211_hw *hw, struct ieee80211_txq *txq);
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+
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+/**
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+ * ieee80211_txq_schedule_start - acquire locks for safe scheduling of an AC
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+ *
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+ * @hw: pointer as obtained from ieee80211_alloc_hw()
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+ * @ac: AC number to acquire locks for
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+ *
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+ * Acquire locks needed to schedule TXQs from the given AC. Should be called
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+ * before ieee80211_next_txq() or ieee80211_return_txq().
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+ */
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+void ieee80211_txq_schedule_start(struct ieee80211_hw *hw, u8 ac)
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+ __acquires(txq_lock);
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+
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+/**
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+ * ieee80211_txq_schedule_end - release locks for safe scheduling of an AC
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+ *
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+ * @hw: pointer as obtained from ieee80211_alloc_hw()
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+ * @ac: AC number to acquire locks for
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+ *
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+ * Release locks previously acquired by ieee80211_txq_schedule_end().
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+ */
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+void ieee80211_txq_schedule_end(struct ieee80211_hw *hw, u8 ac)
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+ __releases(txq_lock);
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+
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+/**
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* ieee80211_txq_get_depth - get pending frame/byte count of given txq
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*
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* The values are not guaranteed to be coherent with regard to each other, i.e.
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--- a/net/mac80211/agg-tx.c
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+++ b/net/mac80211/agg-tx.c
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@@ -229,7 +229,7 @@ ieee80211_agg_start_txq(struct sta_info
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clear_bit(IEEE80211_TXQ_STOP, &txqi->flags);
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local_bh_disable();
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rcu_read_lock();
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- drv_wake_tx_queue(sta->sdata->local, txqi);
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+ schedule_and_wake_txq(sta->sdata->local, txqi);
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rcu_read_unlock();
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local_bh_enable();
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}
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--- a/net/mac80211/driver-ops.h
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+++ b/net/mac80211/driver-ops.h
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@@ -1176,6 +1176,15 @@ static inline void drv_wake_tx_queue(str
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local->ops->wake_tx_queue(&local->hw, &txq->txq);
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}
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+static inline void schedule_and_wake_txq(struct ieee80211_local *local,
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+ struct txq_info *txqi)
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+{
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+ spin_lock_bh(&local->active_txq_lock[txqi->txq.ac]);
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+ ieee80211_return_txq(&local->hw, &txqi->txq);
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+ spin_unlock_bh(&local->active_txq_lock[txqi->txq.ac]);
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+ drv_wake_tx_queue(local, txqi);
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+}
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+
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static inline int drv_start_nan(struct ieee80211_local *local,
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struct ieee80211_sub_if_data *sdata,
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struct cfg80211_nan_conf *conf)
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--- a/net/mac80211/ieee80211_i.h
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+++ b/net/mac80211/ieee80211_i.h
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@@ -829,6 +829,8 @@ enum txq_info_flags {
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* a fq_flow which is already owned by a different tin
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* @def_cvars: codel vars for @def_flow
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* @frags: used to keep fragments created after dequeue
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+ * @schedule_order: used with ieee80211_local->active_txqs
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+ * @schedule_round: counter to prevent infinite loops on TXQ scheduling
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*/
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struct txq_info {
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struct fq_tin tin;
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@@ -836,6 +838,8 @@ struct txq_info {
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struct codel_vars def_cvars;
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struct codel_stats cstats;
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struct sk_buff_head frags;
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+ struct list_head schedule_order;
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+ u16 schedule_round;
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unsigned long flags;
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/* keep last! */
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@@ -1127,6 +1131,11 @@ struct ieee80211_local {
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struct codel_vars *cvars;
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struct codel_params cparams;
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+ /* protects active_txqs and txqi->schedule_order */
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+ spinlock_t active_txq_lock[IEEE80211_NUM_ACS];
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+ struct list_head active_txqs[IEEE80211_NUM_ACS];
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+ u16 schedule_round[IEEE80211_NUM_ACS];
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+
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const struct ieee80211_ops *ops;
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/*
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--- a/net/mac80211/main.c
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+++ b/net/mac80211/main.c
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@@ -652,6 +652,11 @@ struct ieee80211_hw *ieee80211_alloc_hw_
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spin_lock_init(&local->rx_path_lock);
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spin_lock_init(&local->queue_stop_reason_lock);
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+ for (i = 0; i < IEEE80211_NUM_ACS; i++) {
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+ INIT_LIST_HEAD(&local->active_txqs[i]);
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+ spin_lock_init(&local->active_txq_lock[i]);
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+ }
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+
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INIT_LIST_HEAD(&local->chanctx_list);
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mutex_init(&local->chanctx_mtx);
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--- a/net/mac80211/sta_info.c
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+++ b/net/mac80211/sta_info.c
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@@ -1244,7 +1244,7 @@ void ieee80211_sta_ps_deliver_wakeup(str
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if (!txq_has_queue(sta->sta.txq[i]))
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continue;
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- drv_wake_tx_queue(local, to_txq_info(sta->sta.txq[i]));
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+ schedule_and_wake_txq(local, to_txq_info(sta->sta.txq[i]));
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}
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}
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--- a/net/mac80211/tx.c
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+++ b/net/mac80211/tx.c
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@@ -1441,6 +1441,7 @@ void ieee80211_txq_init(struct ieee80211
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codel_vars_init(&txqi->def_cvars);
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codel_stats_init(&txqi->cstats);
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__skb_queue_head_init(&txqi->frags);
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+ INIT_LIST_HEAD(&txqi->schedule_order);
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txqi->txq.vif = &sdata->vif;
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@@ -1464,6 +1465,9 @@ void ieee80211_txq_purge(struct ieee8021
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fq_tin_reset(fq, tin, fq_skb_free_func);
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ieee80211_purge_tx_queue(&local->hw, &txqi->frags);
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+ spin_lock_bh(&local->active_txq_lock[txqi->txq.ac]);
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+ list_del_init(&txqi->schedule_order);
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+ spin_unlock_bh(&local->active_txq_lock[txqi->txq.ac]);
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}
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void ieee80211_txq_set_params(struct ieee80211_local *local)
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@@ -1580,7 +1584,7 @@ static bool ieee80211_queue_skb(struct i
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ieee80211_txq_enqueue(local, txqi, skb);
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spin_unlock_bh(&fq->lock);
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- drv_wake_tx_queue(local, txqi);
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+ schedule_and_wake_txq(local, txqi);
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return true;
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}
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@@ -3600,6 +3604,60 @@ out:
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}
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EXPORT_SYMBOL(ieee80211_tx_dequeue);
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+struct ieee80211_txq *ieee80211_next_txq(struct ieee80211_hw *hw, u8 ac)
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+{
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+ struct ieee80211_local *local = hw_to_local(hw);
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+ struct txq_info *txqi = NULL;
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+
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+ lockdep_assert_held(&local->active_txq_lock[ac]);
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+
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+ txqi = list_first_entry_or_null(&local->active_txqs[ac],
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+ struct txq_info,
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+ schedule_order);
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+
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+ if (!txqi || txqi->schedule_round == local->schedule_round[ac])
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+ return NULL;
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+
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+ list_del_init(&txqi->schedule_order);
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+ txqi->schedule_round = local->schedule_round[ac];
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+ return &txqi->txq;
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+}
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+EXPORT_SYMBOL(ieee80211_next_txq);
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+
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+void ieee80211_return_txq(struct ieee80211_hw *hw,
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+ struct ieee80211_txq *txq)
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+{
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+ struct ieee80211_local *local = hw_to_local(hw);
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+ struct txq_info *txqi = to_txq_info(txq);
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+
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+ lockdep_assert_held(&local->active_txq_lock[txq->ac]);
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+
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+ if (list_empty(&txqi->schedule_order) &&
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+ (!skb_queue_empty(&txqi->frags) || txqi->tin.backlog_packets))
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+ list_add_tail(&txqi->schedule_order,
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+ &local->active_txqs[txq->ac]);
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+}
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+EXPORT_SYMBOL(ieee80211_return_txq);
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+
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+void ieee80211_txq_schedule_start(struct ieee80211_hw *hw, u8 ac)
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+ __acquires(txq_lock)
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+{
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+ struct ieee80211_local *local = hw_to_local(hw);
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+
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+ spin_lock_bh(&local->active_txq_lock[ac]);
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+ local->schedule_round[ac]++;
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+}
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+EXPORT_SYMBOL(ieee80211_txq_schedule_start);
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+
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+void ieee80211_txq_schedule_end(struct ieee80211_hw *hw, u8 ac)
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+ __releases(txq_lock)
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+{
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+ struct ieee80211_local *local = hw_to_local(hw);
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+
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+ spin_unlock_bh(&local->active_txq_lock[ac]);
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+}
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+EXPORT_SYMBOL(ieee80211_txq_schedule_end);
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+
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void __ieee80211_subif_start_xmit(struct sk_buff *skb,
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struct net_device *dev,
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u32 info_flags)
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