mac80211: backport tx queue start/stop fix

Among other things, it fixes a race condition on calling ieee80211_restart_hw

Signed-off-by: Felix Fietkau <nbd@nbd.name>

2 files changed, 273 insertions, 1 deletions

diff --git a/package/kernel/mac80211/patches/398-mac80211-add-stop-start-logic-for-software-TXQs.patch b/package/kernel/mac80211/patches/398-mac80211-add-stop-start-logic-for-software-TXQs.patch
new file mode 100644
index 0000000000..c85e5c6612
--- /dev/null
+++ b/package/kernel/mac80211/patches/398-mac80211-add-stop-start-logic-for-software-TXQs.patch
@@ -0,0 +1,272 @@
+From: Manikanta Pubbisetty <mpubbise@codeaurora.org>
+Date: Wed, 11 Jul 2018 00:12:53 +0530
+Subject: [PATCH] mac80211: add stop/start logic for software TXQs
+
+Sometimes, it is required to stop the transmissions momentarily and
+resume it later; stopping the txqs becomes very critical in scenarios where
+the packet transmission has to be ceased completely. For example, during
+the hardware restart, during off channel operations,
+when initiating CSA(upon detecting a radar on the DFS channel), etc.
+
+The TX queue stop/start logic in mac80211 works well in stopping the TX
+when drivers make use of netdev queues, i.e, when Qdiscs in network layer
+take care of traffic scheduling. Since the devices implementing
+wake_tx_queue can run without Qdiscs, packets will be handed to mac80211
+directly without queueing them in the netdev queues.
+
+Also, mac80211 does not invoke any of the
+netif_stop_*/netif_wake_* APIs if wake_tx_queue is implemented.
+Since the queues are not stopped in this case, transmissions can continue
+and this will impact negatively on the operation of the wireless device.
+
+For example,
+During hardware restart, we stop the netdev queues so that packets are
+not sent to the driver. Since ath10k implements wake_tx_queue,
+TX queues will not be stopped and packets might reach the hardware while
+it is restarting; this can make hardware unresponsive and the only
+possible option for recovery is to reboot the entire system.
+
+There is another problem to this, it is observed that the packets
+were sent on the DFS channel for a prolonged duration after radar
+detection impacting the channel closing time.
+
+We can still invoke netif stop/wake APIs when wake_tx_queue is implemented
+but this could lead to packet drops in network layer; adding stop/start
+logic for software TXQs in mac80211 instead makes more sense; the change
+proposed adds the same in mac80211.
+
+Signed-off-by: Manikanta Pubbisetty <mpubbise@codeaurora.org>
+Signed-off-by: Johannes Berg <johannes.berg@intel.com>
+---
+
+--- a/include/net/mac80211.h
++++ b/include/net/mac80211.h
+@@ -1453,6 +1453,8 @@ enum ieee80211_vif_flags {
+  * @drv_priv: data area for driver use, will always be aligned to
+  *	sizeof(void \*).
+  * @txq: the multicast data TX queue (if driver uses the TXQ abstraction)
++ * @txqs_stopped: per AC flag to indicate that intermediate TXQs are stopped,
++ *	protected by fq->lock.
+  */
+ struct ieee80211_vif {
+ 	enum nl80211_iftype type;
+@@ -1477,6 +1479,8 @@ struct ieee80211_vif {
+ 
+ 	unsigned int probe_req_reg;
+ 
++	bool txqs_stopped[IEEE80211_NUM_ACS];
++
+ 	/* must be last */
+ 	u8 drv_priv[0] __aligned(sizeof(void *));
+ };
+--- a/net/mac80211/ieee80211_i.h
++++ b/net/mac80211/ieee80211_i.h
+@@ -816,6 +816,7 @@ enum txq_info_flags {
+ 	IEEE80211_TXQ_STOP,
+ 	IEEE80211_TXQ_AMPDU,
+ 	IEEE80211_TXQ_NO_AMSDU,
++	IEEE80211_TXQ_STOP_NETIF_TX,
+ };
+ 
+ /**
+@@ -1223,6 +1224,7 @@ struct ieee80211_local {
+ 
+ 	struct sk_buff_head pending[IEEE80211_MAX_QUEUES];
+ 	struct tasklet_struct tx_pending_tasklet;
++	struct tasklet_struct wake_txqs_tasklet;
+ 
+ 	atomic_t agg_queue_stop[IEEE80211_MAX_QUEUES];
+ 
+@@ -2037,6 +2039,7 @@ void ieee80211_txq_purge(struct ieee8021
+ 			 struct txq_info *txqi);
+ void ieee80211_txq_remove_vlan(struct ieee80211_local *local,
+ 			       struct ieee80211_sub_if_data *sdata);
++void ieee80211_wake_txqs(unsigned long data);
+ void ieee80211_send_auth(struct ieee80211_sub_if_data *sdata,
+ 			 u16 transaction, u16 auth_alg, u16 status,
+ 			 const u8 *extra, size_t extra_len, const u8 *bssid,
+--- a/net/mac80211/main.c
++++ b/net/mac80211/main.c
+@@ -671,6 +671,10 @@ struct ieee80211_hw *ieee80211_alloc_hw_
+ 	tasklet_init(&local->tx_pending_tasklet, ieee80211_tx_pending,
+ 		     (unsigned long)local);
+ 
++	if (ops->wake_tx_queue)
++		tasklet_init(&local->wake_txqs_tasklet, ieee80211_wake_txqs,
++			     (unsigned long)local);
++
+ 	tasklet_init(&local->tasklet,
+ 		     ieee80211_tasklet_handler,
+ 		     (unsigned long) local);
+--- a/net/mac80211/tx.c
++++ b/net/mac80211/tx.c
+@@ -3463,13 +3463,19 @@ struct sk_buff *ieee80211_tx_dequeue(str
+ 	struct ieee80211_tx_info *info;
+ 	struct ieee80211_tx_data tx;
+ 	ieee80211_tx_result r;
+-	struct ieee80211_vif *vif;
++	struct ieee80211_vif *vif = txq->vif;
+ 
+ 	spin_lock_bh(&fq->lock);
+ 
+-	if (test_bit(IEEE80211_TXQ_STOP, &txqi->flags))
++	if (test_bit(IEEE80211_TXQ_STOP, &txqi->flags) ||
++	    test_bit(IEEE80211_TXQ_STOP_NETIF_TX, &txqi->flags))
+ 		goto out;
+ 
++	if (vif->txqs_stopped[ieee80211_ac_from_tid(txq->tid)]) {
++		set_bit(IEEE80211_TXQ_STOP_NETIF_TX, &txqi->flags);
++		goto out;
++	}
++
+ 	/* Make sure fragments stay together. */
+ 	skb = __skb_dequeue(&txqi->frags);
+ 	if (skb)
+@@ -3565,6 +3571,7 @@ begin:
+ 	}
+ 
+ 	IEEE80211_SKB_CB(skb)->control.vif = vif;
++
+ out:
+ 	spin_unlock_bh(&fq->lock);
+ 
+--- a/net/mac80211/util.c
++++ b/net/mac80211/util.c
+@@ -239,6 +239,99 @@ __le16 ieee80211_ctstoself_duration(stru
+ }
+ EXPORT_SYMBOL(ieee80211_ctstoself_duration);
+ 
++static void __ieee80211_wake_txqs(struct ieee80211_sub_if_data *sdata, int ac)
++{
++	struct ieee80211_local *local = sdata->local;
++	struct ieee80211_vif *vif = &sdata->vif;
++	struct fq *fq = &local->fq;
++	struct ps_data *ps = NULL;
++	struct txq_info *txqi;
++	struct sta_info *sta;
++	int i;
++
++	spin_lock_bh(&fq->lock);
++
++	if (sdata->vif.type == NL80211_IFTYPE_AP)
++		ps = &sdata->bss->ps;
++
++	sdata->vif.txqs_stopped[ac] = false;
++
++	list_for_each_entry_rcu(sta, &local->sta_list, list) {
++		if (sdata != sta->sdata)
++			continue;
++
++		for (i = 0; i < ARRAY_SIZE(sta->sta.txq); i++) {
++			struct ieee80211_txq *txq = sta->sta.txq[i];
++
++			txqi = to_txq_info(txq);
++
++			if (ac != txq->ac)
++				continue;
++
++			if (!test_and_clear_bit(IEEE80211_TXQ_STOP_NETIF_TX,
++						&txqi->flags))
++				continue;
++
++			spin_unlock_bh(&fq->lock);
++			drv_wake_tx_queue(local, txqi);
++			spin_lock_bh(&fq->lock);
++		}
++	}
++
++	if (!vif->txq)
++		goto out;
++
++	txqi = to_txq_info(vif->txq);
++
++	if (!test_and_clear_bit(IEEE80211_TXQ_STOP_NETIF_TX, &txqi->flags) ||
++	    (ps && atomic_read(&ps->num_sta_ps)) || ac != vif->txq->ac)
++		goto out;
++
++	spin_unlock_bh(&fq->lock);
++
++	drv_wake_tx_queue(local, txqi);
++	return;
++out:
++	spin_unlock_bh(&fq->lock);
++}
++
++void ieee80211_wake_txqs(unsigned long data)
++{
++	struct ieee80211_local *local = (struct ieee80211_local *)data;
++	struct ieee80211_sub_if_data *sdata;
++	int n_acs = IEEE80211_NUM_ACS;
++	unsigned long flags;
++	int i;
++
++	rcu_read_lock();
++	spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
++
++	if (local->hw.queues < IEEE80211_NUM_ACS)
++		n_acs = 1;
++
++	for (i = 0; i < local->hw.queues; i++) {
++		if (local->queue_stop_reasons[i])
++			continue;
++
++		spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);
++		list_for_each_entry_rcu(sdata, &local->interfaces, list) {
++			int ac;
++
++			for (ac = 0; ac < n_acs; ac++) {
++				int ac_queue = sdata->vif.hw_queue[ac];
++
++				if (ac_queue == i ||
++				    sdata->vif.cab_queue == i)
++					__ieee80211_wake_txqs(sdata, ac);
++			}
++		}
++		spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
++	}
++
++	spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);
++	rcu_read_unlock();
++}
++
+ void ieee80211_propagate_queue_wake(struct ieee80211_local *local, int queue)
+ {
+ 	struct ieee80211_sub_if_data *sdata;
+@@ -307,6 +400,9 @@ static void __ieee80211_wake_queue(struc
+ 		rcu_read_unlock();
+ 	} else
+ 		tasklet_schedule(&local->tx_pending_tasklet);
++
++	if (local->ops->wake_tx_queue)
++		tasklet_schedule(&local->wake_txqs_tasklet);
+ }
+ 
+ void ieee80211_wake_queue_by_reason(struct ieee80211_hw *hw, int queue,
+@@ -350,9 +446,6 @@ static void __ieee80211_stop_queue(struc
+ 	if (__test_and_set_bit(reason, &local->queue_stop_reasons[queue]))
+ 		return;
+ 
+-	if (local->ops->wake_tx_queue)
+-		return;
+-
+ 	if (local->hw.queues < IEEE80211_NUM_ACS)
+ 		n_acs = 1;
+ 
+@@ -365,8 +458,15 @@ static void __ieee80211_stop_queue(struc
+ 
+ 		for (ac = 0; ac < n_acs; ac++) {
+ 			if (sdata->vif.hw_queue[ac] == queue ||
+-			    sdata->vif.cab_queue == queue)
+-				netif_stop_subqueue(sdata->dev, ac);
++			    sdata->vif.cab_queue == queue) {
++				if (!local->ops->wake_tx_queue) {
++					netif_stop_subqueue(sdata->dev, ac);
++					continue;
++				}
++				spin_lock(&local->fq.lock);
++				sdata->vif.txqs_stopped[ac] = true;
++				spin_unlock(&local->fq.lock);
++			}
+ 		}
+ 	}
+ 	rcu_read_unlock();
diff --git a/package/kernel/mac80211/patches/522-mac80211_configure_antenna_gain.patch b/package/kernel/mac80211/patches/522-mac80211_configure_antenna_gain.patch
index b815f5f22a..8a149dcb83 100644
--- a/package/kernel/mac80211/patches/522-mac80211_configure_antenna_gain.patch
+++ b/package/kernel/mac80211/patches/522-mac80211_configure_antenna_gain.patch
@@ -87,7 +87,7 @@
  	CFG80211_TESTMODE_CMD(ieee80211_testmode_cmd)
 --- a/net/mac80211/ieee80211_i.h
 +++ b/net/mac80211/ieee80211_i.h
-@@ -1348,6 +1348,7 @@ struct ieee80211_local {
+@@ -1350,6 +1350,7 @@ struct ieee80211_local {
  	int dynamic_ps_forced_timeout;
  
  	int user_power_level; /* in dBm, for all interfaces */