From: Johannes Berg 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 --- --- a/net/mac80211/tx.c +++ b/net/mac80211/tx.c @@ -5,7 +5,7 @@ * Copyright 2006-2007 Jiri Benc * Copyright 2007 Johannes Berg * 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)