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 includes only the ac number
instead of the TXQ. The driver is expected to retrieve TXQs 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). Drivers
can optionally filter TXQs on ac to support per-AC hardware queue
designs.
Usage of the new API is optional, so drivers can be ported one at a time.
Signed-off-by: Toke Høiland-Jørgensen <toke@xxxxxxx>
---
include/net/mac80211.h | 45 ++++++++++++++++++++++++++++++---
net/mac80211/agg-tx.c | 2 +
net/mac80211/driver-ops.h | 7 +++++
net/mac80211/ieee80211_i.h | 9 +++++++
net/mac80211/main.c | 4 +++
net/mac80211/sta_info.c | 2 +
net/mac80211/tx.c | 60 +++++++++++++++++++++++++++++++++++++++++++-
7 files changed, 122 insertions(+), 7 deletions(-)
diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index c4fadbafbf21..ff413d9caa50 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -108,9 +108,16 @@
* 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 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
@@ -6045,13 +6052,43 @@ 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 station or virtual interface, or from
+ * ieee80211_next_txq()
*
* Returns the skb if successful, %NULL if no frame was available.
*/
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()
+ * @ac: AC number to return packets from.
+ * @first: Setting this to true signifies the start of a new scheduling round.
+ * Each TXQ will only be returned at most exactly once in each round.
+ *
+ * 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. Note
+ * that the driver is responsible for locking to ensuring two different threads
+ * don't schedule the same AC simultaneously.
+ */
+struct ieee80211_txq *ieee80211_next_txq(struct ieee80211_hw *hw, s8 ac,
+ bool first);
+
/**
* ieee80211_txq_get_depth - get pending frame/byte count of given txq
*
diff --git a/net/mac80211/agg-tx.c b/net/mac80211/agg-tx.c
index 69e831bc317b..e94b1a0407af 100644
--- a/net/mac80211/agg-tx.c
+++ b/net/mac80211/agg-tx.c
@@ -229,7 +229,7 @@ ieee80211_agg_start_txq(struct sta_info *sta, int tid, bool enable)
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();
}
diff --git a/net/mac80211/driver-ops.h b/net/mac80211/driver-ops.h
index e42c641b6190..f1578c394f75 100644
--- a/net/mac80211/driver-ops.h
+++ b/net/mac80211/driver-ops.h
@@ -1173,6 +1173,13 @@ static inline void drv_wake_tx_queue(struct ieee80211_local *local,
local->ops->wake_tx_queue(&local->hw, &txq->txq);
}
+static inline void schedule_and_wake_txq(struct ieee80211_local *local,
+ struct txq_info *txqi)
+{
+ ieee80211_schedule_txq(&local->hw, &txqi->txq);
+ drv_wake_tx_queue(local, txqi);
+}
+
static inline int drv_can_aggregate_in_amsdu(struct ieee80211_local *local,
struct sk_buff *head,
struct sk_buff *skb)
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index f40a2167935f..75f9c9ab364f 100644
--- 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;
+ struct list_head active_txqs[IEEE80211_NUM_ACS];
+ u16 schedule_round[IEEE80211_NUM_ACS];
+
const struct ieee80211_ops *ops;
/*
diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index 77381017bac7..c6d88758cbb7 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -663,6 +663,10 @@ struct ieee80211_hw *ieee80211_alloc_hw_nm(size_t priv_data_len,
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);
+
INIT_LIST_HEAD(&local->chanctx_list);
mutex_init(&local->chanctx_mtx);
diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index fb8c2252ac0e..c2f5cb7df54f 100644
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -1249,7 +1249,7 @@ void ieee80211_sta_ps_deliver_wakeup(struct sta_info *sta)
if (!sta->sta.txq[i] || !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]));
}
skb_queue_head_init(&pending);
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index c42bfa1dcd2c..8bcc447e2cbc 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -1445,6 +1445,7 @@ void ieee80211_txq_init(struct ieee80211_sub_if_data *sdata,
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;
@@ -1485,6 +1486,9 @@ void ieee80211_txq_purge(struct ieee80211_local *local,
fq_tin_reset(fq, tin, fq_skb_free_func);
ieee80211_purge_tx_queue(&local->hw, &txqi->frags);
+ spin_lock_bh(&local->active_txq_lock);
+ list_del_init(&txqi->schedule_order);
+ spin_unlock_bh(&local->active_txq_lock);
}
void ieee80211_txq_set_params(struct ieee80211_local *local)
@@ -1601,7 +1605,7 @@ static bool ieee80211_queue_skb(struct ieee80211_local *local,
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;
}
@@ -3623,6 +3627,60 @@ struct sk_buff *ieee80211_tx_dequeue(struct ieee80211_hw *hw,
}
EXPORT_SYMBOL(ieee80211_tx_dequeue);
+bool ieee80211_schedule_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);
+ bool ret = false;
+
+ spin_lock_bh(&local->active_txq_lock);
+
+ if (list_empty(&txqi->schedule_order)) {
+ list_add_tail(&txqi->schedule_order,
+ &local->active_txqs[txq->ac]);
+ ret = true;
+ }
+
+ spin_unlock_bh(&local->active_txq_lock);
+
+ return ret;
+}
+EXPORT_SYMBOL(ieee80211_schedule_txq);
+
+struct ieee80211_txq *ieee80211_next_txq(struct ieee80211_hw *hw, s8 ac,
+ bool first)
+{
+ struct ieee80211_local *local = hw_to_local(hw);
+ struct txq_info *txqi = NULL;
+
+ spin_lock_bh(&local->active_txq_lock);
+
+ if (first)
+ local->schedule_round[ac]++;
+
+ if (list_empty(&local->active_txqs[ac]))
+ goto out;
+
+ txqi = list_first_entry(&local->active_txqs[ac],
+ struct txq_info,
+ schedule_order);
+
+ if (txqi->schedule_round == local->schedule_round[ac])
+ txqi = NULL;
+ else
+ list_del_init(&txqi->schedule_order);
+ out:
+ spin_unlock_bh(&local->active_txq_lock);
+
+ if (!txqi)
+ return NULL;
+
+ txqi->schedule_round = local->schedule_round[ac];
+ return &txqi->txq;
+}
+EXPORT_SYMBOL(ieee80211_next_txq);
+
void __ieee80211_subif_start_xmit(struct sk_buff *skb,
struct net_device *dev,
u32 info_flags)
