mac80211: merge a few pending tx related fixes

Improve performance and fix potential mgmt tx hangs/warnings

Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: maurerr <mariusd84@gmail.com>
This commit is contained in:
Felix Fietkau 2021-03-28 12:15:42 +02:00 committed by maurerr
parent d3b34038eb
commit ab5b2dd9fb
3 changed files with 142 additions and 0 deletions

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@ -0,0 +1,61 @@
From: Johannes Berg <johannes.berg@intel.com>
Date: Tue, 23 Mar 2021 21:05:01 +0100
Subject: [PATCH] mac80211: fix TXQ AC confusion
Normally, TXQs have
txq->tid = tid;
txq->ac = ieee80211_ac_from_tid(tid);
However, the special management TXQ actually has
txq->tid = IEEE80211_NUM_TIDS; // 16
txq->ac = IEEE80211_AC_VO;
This makes sense, but ieee80211_ac_from_tid(16) is the same
as ieee80211_ac_from_tid(0) which is just IEEE80211_AC_BE.
Now, normally this is fine. However, if the netdev queues
were stopped, then the code in ieee80211_tx_dequeue() will
propagate the stop from the interface (vif->txqs_stopped[])
if the AC 2 (ieee80211_ac_from_tid(txq->tid)) is marked as
stopped. On wake, however, __ieee80211_wake_txqs() will wake
the TXQ if AC 0 (txq->ac) is woken up.
If a driver stops all queues with ieee80211_stop_tx_queues()
and then wakes them again with ieee80211_wake_tx_queues(),
the ieee80211_wake_txqs() tasklet will run to resync queue
and TXQ state. If all queues were woken, then what'll happen
is that _ieee80211_wake_txqs() will run in order of HW queues
0-3, typically (and certainly for iwlwifi) corresponding to
ACs 0-3, so it'll call __ieee80211_wake_txqs() for each AC in
order 0-3.
When __ieee80211_wake_txqs() is called for AC 0 (VO) that'll
wake up the management TXQ (remember its tid is 16), and the
driver's wake_tx_queue() will be called. That tries to get a
frame, which will immediately *stop* the TXQ again, because
now we check against AC 2, and AC 2 hasn't yet been marked as
woken up again in sdata->vif.txqs_stopped[] since we're only
in the __ieee80211_wake_txqs() call for AC 0.
Thus, the management TXQ will never be started again.
Fix this by checking txq->ac directly instead of calculating
the AC as ieee80211_ac_from_tid(txq->tid).
Fixes: adf8ed01e4fd ("mac80211: add an optional TXQ for other PS-buffered frames")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -3589,7 +3589,7 @@ begin:
test_bit(IEEE80211_TXQ_STOP_NETIF_TX, &txqi->flags))
goto out;
- if (vif->txqs_stopped[ieee80211_ac_from_tid(txq->tid)]) {
+ if (vif->txqs_stopped[txq->ac]) {
set_bit(IEEE80211_TXQ_STOP_NETIF_TX, &txqi->flags);
goto out;
}

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From: Johannes Berg <johannes.berg@intel.com>
Date: Fri, 19 Mar 2021 23:28:01 +0100
Subject: [PATCH] mac80211: don't apply flow control on management frames
In some cases (depending on the driver, but it's true e.g. for
iwlwifi) we're using an internal TXQ for management packets,
mostly to simplify the code and to have a place to queue them.
However, it appears that in certain cases we can confuse the
code and management frames are dropped, which is certainly not
what we want.
Short-circuit the processing of management frames. To keep the
impact minimal, only put them on the frags queue and check the
tid == management only for doing that and to skip the airtime
fairness checks, if applicable.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -5,7 +5,7 @@
* Copyright 2006-2007 Jiri Benc <jbenc@suse.cz>
* Copyright 2007 Johannes Berg <johannes@sipsolutions.net>
* Copyright 2013-2014 Intel Mobile Communications GmbH
- * Copyright (C) 2018-2020 Intel Corporation
+ * Copyright (C) 2018-2021 Intel Corporation
*
* Transmit and frame generation functions.
*/
@@ -1403,8 +1403,17 @@ static void ieee80211_txq_enqueue(struct
ieee80211_set_skb_enqueue_time(skb);
spin_lock_bh(&fq->lock);
- fq_tin_enqueue(fq, tin, flow_idx, skb,
- fq_skb_free_func);
+ /*
+ * For management frames, don't really apply codel etc.,
+ * we don't want to apply any shaping or anything we just
+ * want to simplify the driver API by having them on the
+ * txqi.
+ */
+ if (unlikely(txqi->txq.tid == IEEE80211_NUM_TIDS))
+ __skb_queue_tail(&txqi->frags, skb);
+ else
+ fq_tin_enqueue(fq, tin, flow_idx, skb,
+ fq_skb_free_func);
spin_unlock_bh(&fq->lock);
}
@@ -3846,6 +3855,9 @@ bool ieee80211_txq_airtime_check(struct
if (!txq->sta)
return true;
+ if (unlikely(txq->tid == IEEE80211_NUM_TIDS))
+ return true;
+
sta = container_of(txq->sta, struct sta_info, sta);
if (atomic_read(&sta->airtime[txq->ac].aql_tx_pending) <
sta->airtime[txq->ac].aql_limit_low)

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From: Lorenzo Bianconi <lorenzo@kernel.org>
Date: Mon, 8 Mar 2021 23:01:49 +0100
Subject: [PATCH] mac80211: set sk_pacing_shift for 802.3 txpath
Similar to 802.11 txpath, set socket sk_pacing_shift for 802.3 tx path.
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
---
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -4173,6 +4173,9 @@ static bool ieee80211_tx_8023(struct iee
unsigned long flags;
int q = info->hw_queue;
+ if (sta)
+ sk_pacing_shift_update(skb->sk, local->hw.tx_sk_pacing_shift);
+
if (ieee80211_queue_skb(local, sdata, sta, skb))
return true;