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wifi: mac80211: Proper mark iTXQs for resumption
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When a running wake_tx_queue() call is aborted due to a hw queue stop
the corresponding iTXQ is not always correctly marked for resumption:
wake_tx_push_queue() can stops the queue run without setting
@IEEE80211_TXQ_STOP_NETIF_TX.

Without the @IEEE80211_TXQ_STOP_NETIF_TX flag __ieee80211_wake_txqs()
will not schedule a new queue run and remaining frames in the queue get
stuck till another frame is queued to it.

Fix the issue for all drivers - also the ones with custom wake_tx_queue
callbacks - by moving the logic into ieee80211_tx_dequeue() and drop the
redundant @txqs_stopped.

@IEEE80211_TXQ_STOP_NETIF_TX is also renamed to @IEEE80211_TXQ_DIRTY to
better describe the flag.

Fixes: c850e31 ("wifi: mac80211: add internal handler for wake_tx_queue")
Signed-off-by: Alexander Wetzel <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Cc: [email protected]
Signed-off-by: Johannes Berg <[email protected]>
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@alexw65500 @jmberg-intel
alexw65500 authored and jmberg-intel committed Jan 10, 2023
1 parent e66b792 commit 4444bc2
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Showing 6 changed files with 21 additions and 54 deletions.
4 changes: 0 additions & 4 deletions include/net/mac80211.h
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Original file line number Diff line number Diff line change
Expand Up @@ -1832,8 +1832,6 @@ struct ieee80211_vif_cfg {
* @drv_priv: data area for driver use, will always be aligned to
* sizeof(void \*).
* @txq: the multicast data TX queue
* @txqs_stopped: per AC flag to indicate that intermediate TXQs are stopped,
* protected by fq->lock.
* @offload_flags: 802.3 -> 802.11 enapsulation offload flags, see
* &enum ieee80211_offload_flags.
* @mbssid_tx_vif: Pointer to the transmitting interface if MBSSID is enabled.
Expand Down Expand Up @@ -1863,8 +1861,6 @@ struct ieee80211_vif {
bool probe_req_reg;
bool rx_mcast_action_reg;

bool txqs_stopped[IEEE80211_NUM_ACS];

struct ieee80211_vif *mbssid_tx_vif;

/* must be last */
Expand Down
5 changes: 3 additions & 2 deletions net/mac80211/debugfs_sta.c
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Original file line number Diff line number Diff line change
Expand Up @@ -167,7 +167,7 @@ static ssize_t sta_aqm_read(struct file *file, char __user *userbuf,
continue;
txqi = to_txq_info(sta->sta.txq[i]);
p += scnprintf(p, bufsz + buf - p,
"%d %d %u %u %u %u %u %u %u %u %u 0x%lx(%s%s%s)\n",
"%d %d %u %u %u %u %u %u %u %u %u 0x%lx(%s%s%s%s)\n",
txqi->txq.tid,
txqi->txq.ac,
txqi->tin.backlog_bytes,
Expand All @@ -182,7 +182,8 @@ static ssize_t sta_aqm_read(struct file *file, char __user *userbuf,
txqi->flags,
test_bit(IEEE80211_TXQ_STOP, &txqi->flags) ? "STOP" : "RUN",
test_bit(IEEE80211_TXQ_AMPDU, &txqi->flags) ? " AMPDU" : "",
test_bit(IEEE80211_TXQ_NO_AMSDU, &txqi->flags) ? " NO-AMSDU" : "");
test_bit(IEEE80211_TXQ_NO_AMSDU, &txqi->flags) ? " NO-AMSDU" : "",
test_bit(IEEE80211_TXQ_DIRTY, &txqi->flags) ? " DIRTY" : "");
}

rcu_read_unlock();
Expand Down
2 changes: 1 addition & 1 deletion net/mac80211/driver-ops.h
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Original file line number Diff line number Diff line change
Expand Up @@ -1199,7 +1199,7 @@ static inline void drv_wake_tx_queue(struct ieee80211_local *local,

/* In reconfig don't transmit now, but mark for waking later */
if (local->in_reconfig) {
set_bit(IEEE80211_TXQ_STOP_NETIF_TX, &txq->flags);
set_bit(IEEE80211_TXQ_DIRTY, &txq->flags);
return;
}

Expand Down
2 changes: 1 addition & 1 deletion net/mac80211/ieee80211_i.h
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Original file line number Diff line number Diff line change
Expand Up @@ -838,7 +838,7 @@ enum txq_info_flags {
IEEE80211_TXQ_STOP,
IEEE80211_TXQ_AMPDU,
IEEE80211_TXQ_NO_AMSDU,
IEEE80211_TXQ_STOP_NETIF_TX,
IEEE80211_TXQ_DIRTY,
};

/**
Expand Down
20 changes: 13 additions & 7 deletions net/mac80211/tx.c
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Original file line number Diff line number Diff line change
Expand Up @@ -3783,23 +3783,29 @@ struct sk_buff *ieee80211_tx_dequeue(struct ieee80211_hw *hw,
struct ieee80211_tx_data tx;
ieee80211_tx_result r;
struct ieee80211_vif *vif = txq->vif;
int q = vif->hw_queue[txq->ac];
bool q_stopped;

WARN_ON_ONCE(softirq_count() == 0);

if (!ieee80211_txq_airtime_check(hw, txq))
return NULL;

begin:
spin_lock_bh(&fq->lock);
spin_lock(&local->queue_stop_reason_lock);
q_stopped = local->queue_stop_reasons[q];
spin_unlock(&local->queue_stop_reason_lock);

if (test_bit(IEEE80211_TXQ_STOP, &txqi->flags) ||
test_bit(IEEE80211_TXQ_STOP_NETIF_TX, &txqi->flags))
goto out;
if (unlikely(q_stopped)) {
/* mark for waking later */
set_bit(IEEE80211_TXQ_DIRTY, &txqi->flags);
return NULL;
}

if (vif->txqs_stopped[txq->ac]) {
set_bit(IEEE80211_TXQ_STOP_NETIF_TX, &txqi->flags);
spin_lock_bh(&fq->lock);

if (unlikely(test_bit(IEEE80211_TXQ_STOP, &txqi->flags)))
goto out;
}

/* Make sure fragments stay together. */
skb = __skb_dequeue(&txqi->frags);
Expand Down
42 changes: 3 additions & 39 deletions net/mac80211/util.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -292,22 +292,12 @@ static void wake_tx_push_queue(struct ieee80211_local *local,
struct ieee80211_sub_if_data *sdata,
struct ieee80211_txq *queue)
{
int q = sdata->vif.hw_queue[queue->ac];
struct ieee80211_tx_control control = {
.sta = queue->sta,
};
struct sk_buff *skb;
unsigned long flags;
bool q_stopped;

while (1) {
spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
q_stopped = local->queue_stop_reasons[q];
spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);

if (q_stopped)
break;

skb = ieee80211_tx_dequeue(&local->hw, queue);
if (!skb)
break;
Expand Down Expand Up @@ -347,8 +337,6 @@ static void __ieee80211_wake_txqs(struct ieee80211_sub_if_data *sdata, int ac)
local_bh_disable();
spin_lock(&fq->lock);

sdata->vif.txqs_stopped[ac] = false;

if (!test_bit(SDATA_STATE_RUNNING, &sdata->state))
goto out;

Expand All @@ -370,7 +358,7 @@ static void __ieee80211_wake_txqs(struct ieee80211_sub_if_data *sdata, int ac)
if (ac != txq->ac)
continue;

if (!test_and_clear_bit(IEEE80211_TXQ_STOP_NETIF_TX,
if (!test_and_clear_bit(IEEE80211_TXQ_DIRTY,
&txqi->flags))
continue;

Expand All @@ -385,7 +373,7 @@ static void __ieee80211_wake_txqs(struct ieee80211_sub_if_data *sdata, int ac)

txqi = to_txq_info(vif->txq);

if (!test_and_clear_bit(IEEE80211_TXQ_STOP_NETIF_TX, &txqi->flags) ||
if (!test_and_clear_bit(IEEE80211_TXQ_DIRTY, &txqi->flags) ||
(ps && atomic_read(&ps->num_sta_ps)) || ac != vif->txq->ac)
goto out;

Expand Down Expand Up @@ -517,8 +505,6 @@ static void __ieee80211_stop_queue(struct ieee80211_hw *hw, int queue,
bool refcounted)
{
struct ieee80211_local *local = hw_to_local(hw);
struct ieee80211_sub_if_data *sdata;
int n_acs = IEEE80211_NUM_ACS;

trace_stop_queue(local, queue, reason);

Expand All @@ -530,29 +516,7 @@ static void __ieee80211_stop_queue(struct ieee80211_hw *hw, int queue,
else
local->q_stop_reasons[queue][reason]++;

if (__test_and_set_bit(reason, &local->queue_stop_reasons[queue]))
return;

if (local->hw.queues < IEEE80211_NUM_ACS)
n_acs = 1;

rcu_read_lock();
list_for_each_entry_rcu(sdata, &local->interfaces, list) {
int ac;

if (!sdata->dev)
continue;

for (ac = 0; ac < n_acs; ac++) {
if (sdata->vif.hw_queue[ac] == queue ||
sdata->vif.cab_queue == queue) {
spin_lock(&local->fq.lock);
sdata->vif.txqs_stopped[ac] = true;
spin_unlock(&local->fq.lock);
}
}
}
rcu_read_unlock();
set_bit(reason, &local->queue_stop_reasons[queue]);
}

void ieee80211_stop_queue_by_reason(struct ieee80211_hw *hw, int queue,
Expand Down

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