Revert "mac80211: Add airtime account and scheduling to TXQs"

This reverts commit b0d52ad821843a6c5badebd80feef9f871904fa6.

We need to revert the TXQ scheduling API due to conflicts
with a new driver, and this depends on that API.

Signed-off-by: Johannes Berg <[e-mail]>

include/net/mac80211.h

···
  *	HT or VHT is used (%RX_FLAG_HT/%RX_FLAG_VHT)
  * @nss: number of streams (VHT and HE only)
  * @flag: %RX_FLAG_\*
- * @airtime: Duration of frame in usec. See @IEEE80211_HW_AIRTIME_ACCOUNTING for
- *       how to use this.
  * @encoding: &enum mac80211_rx_encoding
  * @bw: &enum rate_info_bw
  * @enc_flags: uses bits from &enum mac80211_rx_encoding_flags
···
 	u32 device_timestamp;
 	u32 ampdu_reference;
 	u32 flag;
-	u16 airtime;
 	u16 freq;
 	u8 enc_flags;
 	u8 encoding:2, bw:3;
···
  * @IEEE80211_HW_SUPPORTS_TDLS_BUFFER_STA: Hardware supports buffer STA on
  *	TDLS links.
  *
- * @IEEE80211_HW_AIRTIME_ACCOUNTING: Hardware supports accounting the airtime
- *      usage of other stations and reports it in the @tx_time and/or @airtime
- *      fields of the TX/RX status structs.
- *      When setting this flag, the driver should ensure that the respective
- *      fields in the TX and RX status structs are always either zero or
- *      contains a valid duration for the frame in usec. The driver can choose
- *      to report either or both of TX and RX airtime, but it is recommended to
- *      report both.
- *      The reported airtime should as a minimum include all time that is spent
- *      transmitting to the remote station, including overhead and padding, but
- *      not including time spent waiting for a TXOP. If the time is not reported
- *      by the hardware it can in some cases be calculated from the rate and
- *      known frame composition. When possible, the time should include any
- *      failed transmission attempts.
- *      For aggregated frames, there are two possible strategies to report the
- *      airtime: Either include the airtime of the entire aggregate in the first
- *      (or last) frame and leave the others at zero. Alternatively, include the
- *      overhead of the full aggregate in the first or last frame and report the
- *      time of each frame + padding not including the full aggregate overhead.
- *
  * @NUM_IEEE80211_HW_FLAGS: number of hardware flags, used for sizing arrays
  */
 enum ieee80211_hw_flags {
···
 	IEEE80211_HW_REPORTS_LOW_ACK,
 	IEEE80211_HW_SUPPORTS_TX_FRAG,
 	IEEE80211_HW_SUPPORTS_TDLS_BUFFER_STA,
-	IEEE80211_HW_AIRTIME_ACCOUNTING,
 
 	/* keep last, obviously */
 	NUM_IEEE80211_HW_FLAGS

net/mac80211/debugfs.c

···
 	FLAG(REPORTS_LOW_ACK),
 	FLAG(SUPPORTS_TX_FRAG),
 	FLAG(SUPPORTS_TDLS_BUFFER_STA),
-	FLAG(AIRTIME_ACCOUNTING),
 #undef FLAG
 };
 

net/mac80211/debugfs_sta.c

···
 }
 STA_OPS(aqm);
 
-static ssize_t sta_airtime_read(struct file *file, char __user *userbuf,
-				size_t count, loff_t *ppos)
-{
-	struct sta_info *sta = file->private_data;
-	size_t bufsz = 200;
-	char *buf = kzalloc(bufsz, GFP_KERNEL), *p = buf;
-	ssize_t rv;
-
-	if (!buf)
-		return -ENOMEM;
-
-	spin_lock_bh(&sta->lock);
-
-	p += scnprintf(p, bufsz + buf - p,
-		"RX: %llu us\nTX: %llu us\nDeficit: %lld us\n",
-		sta->airtime_stats.rx_airtime,
-		sta->airtime_stats.tx_airtime,
-		sta->airtime_deficit);
-
-	spin_unlock_bh(&sta->lock);
-	rv = simple_read_from_buffer(userbuf, count, ppos, buf, p - buf);
-	kfree(buf);
-	return rv;
-}
-STA_OPS(airtime);
-
 static ssize_t sta_agg_status_read(struct file *file, char __user *userbuf,
 					size_t count, loff_t *ppos)
 {
···
 
 	if (local->ops->wake_tx_queue)
 		DEBUGFS_ADD(aqm);
-
-	if (ieee80211_hw_check(&local->hw, AIRTIME_ACCOUNTING))
-		DEBUGFS_ADD(airtime);
 
 	if (sizeof(sta->driver_buffered_tids) == sizeof(u32))
 		debugfs_create_x32("driver_buffered_tids", 0400,

net/mac80211/ieee80211_i.h

···
 
 #define IEEE80211_MAX_NAN_INSTANCE_ID 255
 
-/* How much to increase airtime deficit on each scheduling round */
-#define IEEE80211_AIRTIME_QUANTUM        1000 /* usec */
-
 struct ieee80211_fragment_entry {
 	struct sk_buff_head skb_list;
 	unsigned long first_frag_time;
···
 	struct codel_vars *cvars;
 	struct codel_params cparams;
 
-	/* protects active_txqs_{new,old} and txqi->schedule_order */
+	/* protects active_txqs and txqi->schedule_order */
 	spinlock_t active_txq_lock;
-	struct list_head active_txqs_new;
-	struct list_head active_txqs_old;
+	struct list_head active_txqs;
 
 	const struct ieee80211_ops *ops;
 

net/mac80211/main.c

···
 	spin_lock_init(&local->rx_path_lock);
 	spin_lock_init(&local->queue_stop_reason_lock);
 
-	INIT_LIST_HEAD(&local->active_txqs_new);
-	INIT_LIST_HEAD(&local->active_txqs_old);
+	INIT_LIST_HEAD(&local->active_txqs);
 	spin_lock_init(&local->active_txq_lock);
 
 	INIT_LIST_HEAD(&local->chanctx_list);

net/mac80211/rx.c

···
 	if (ieee80211_vif_is_mesh(&rx->sdata->vif))
 		ieee80211_mps_rx_h_sta_process(sta, hdr);
 
-	/* airtime accounting */
-	if (status->airtime) {
-		spin_lock_bh(&sta->lock);
-		sta->airtime_stats.rx_airtime += status->airtime;
-		sta->airtime_deficit -= status->airtime;
-		spin_unlock_bh(&sta->lock);
-	}
-
 	/*
 	 * Drop (qos-)data::nullfunc frames silently, since they
 	 * are used only to control station power saving mode.

net/mac80211/sta_info.c

···
 	sta->cparams.interval = MS2TIME(100);
 	sta->cparams.ecn = true;
 
-	sta->airtime_deficit = IEEE80211_AIRTIME_QUANTUM;
-
 	sta_dbg(sdata, "Allocated STA %pM\n", sta->sta.addr);
 
 	return sta;

net/mac80211/sta_info.h

···
 	} tx_stats;
 	u16 tid_seq[IEEE80211_QOS_CTL_TID_MASK + 1];
 
-	/* Airtime stats and deficit, protected by lock */
-	struct {
-		u64 rx_airtime;
-		u64 tx_airtime;
-	} airtime_stats;
-	s64 airtime_deficit;
-
 	/*
 	 * Aggregation information, locked with lock.
 	 */

net/mac80211/status.c

···
 				ieee80211_lost_packet(sta, info);
 			}
 		}
-
-		if (info->status.tx_time &&
-		    ieee80211_hw_check(&local->hw, AIRTIME_ACCOUNTING)) {
-			spin_lock_bh(&sta->lock);
-			sta->airtime_stats.tx_airtime += info->status.tx_time;
-			sta->airtime_deficit -= info->status.tx_time;
-			spin_unlock_bh(&sta->lock);
-		}
 	}
 
 	/* SNMP counters
···
 		if (!acked)
 			sta->status_stats.retry_failed++;
 		sta->status_stats.retry_count += retry_count;
-
-		if (info->status.tx_time &&
-		    ieee80211_hw_check(&local->hw, AIRTIME_ACCOUNTING)) {
-			spin_lock_bh(&sta->lock);
-			sta->airtime_stats.tx_airtime += info->status.tx_time;
-			sta->airtime_deficit -= info->status.tx_time;
-			spin_unlock_bh(&sta->lock);
-		}
 
 		if (acked) {
 			sta->status_stats.last_ack = jiffies;

net/mac80211/tx.c

···
 	spin_lock_bh(&local->active_txq_lock);
 
 	if (list_empty(&txqi->schedule_order)) {
-		list_add_tail(&txqi->schedule_order, &local->active_txqs_new);
+		list_add_tail(&txqi->schedule_order, &local->active_txqs);
 		ret = true;
 	}
 
···
 {
 	struct ieee80211_local *local = hw_to_local(hw);
 	struct txq_info *txqi = NULL;
-	struct list_head *head;
 
 	spin_lock_bh(&local->active_txq_lock);
 
-begin:
-	head = &local->active_txqs_new;
-	if (list_empty(head)) {
-		head = &local->active_txqs_old;
-		if (list_empty(head))
-			goto out;
-	}
+	if (list_empty(&local->active_txqs))
+		goto out;
 
-	txqi = list_first_entry(head, struct txq_info, schedule_order);
-
-	if (txqi->txq.sta) {
-		struct sta_info *sta = container_of(txqi->txq.sta,
-						struct sta_info, sta);
-
-		spin_lock_bh(&sta->lock);
-		if (sta->airtime_deficit < 0) {
-			sta->airtime_deficit += IEEE80211_AIRTIME_QUANTUM;
-			list_move_tail(&txqi->schedule_order,
-				       &local->active_txqs_old);
-			spin_unlock_bh(&sta->lock);
-			goto begin;
-		}
-		spin_unlock_bh(&sta->lock);
-	}
-
+	txqi = list_first_entry(&local->active_txqs,
+				struct txq_info, schedule_order);
 	list_del_init(&txqi->schedule_order);
 
 out: