LinuxLists.cc - [PATCH] wifi: mac80211: Proper mark iTXQs for resumption

2022-12-30 12:32:06

Subject: [PATCH] wifi: mac80211: Proper mark iTXQs for resumption

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: c850e31f79f0 ("wifi: mac80211: add internal handler for wake_tx_queue")
Signed-off-by: Alexander Wetzel <[email protected]>
---
include/net/mac80211.h | 4 ----
net/mac80211/debugfs_sta.c | 5 +++--
net/mac80211/driver-ops.h | 2 +-
net/mac80211/ieee80211_i.h | 2 +-
net/mac80211/tx.c | 20 +++++++++++-------
net/mac80211/util.c | 42 +++-----------------------------------
6 files changed, 21 insertions(+), 54 deletions(-)

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 689da327ce2e..e3235b9c02c2 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -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.
@@ -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 */
diff --git a/net/mac80211/debugfs_sta.c b/net/mac80211/debugfs_sta.c
index 7a3d7893e19d..f1914bf39f0e 100644
--- a/net/mac80211/debugfs_sta.c
+++ b/net/mac80211/debugfs_sta.c
@@ -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,
@@ -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();
diff --git a/net/mac80211/driver-ops.h b/net/mac80211/driver-ops.h
index 809bad53e15b..5d13a3dfd366 100644
--- a/net/mac80211/driver-ops.h
+++ b/net/mac80211/driver-ops.h
@@ -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;
}

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 63ff0d2524b6..d16606e84e22 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -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,
};

/**
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 2171cd1ca807..178043f84489 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -3783,6 +3783,8 @@ 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);

@@ -3790,16 +3792,20 @@ struct sk_buff *ieee80211_tx_dequeue(struct ieee80211_hw *hw,
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);
diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index 6f5407038459..261ac667887f 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -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;
@@ -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;

@@ -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;

@@ -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;

@@ -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);

@@ -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,
--
2.39.0

2023-01-10 19:39:23

by Bryan O'Donoghue

[permalink] [raw]

Subject: Re: [PATCH] wifi: mac80211: Proper mark iTXQs for resumption

On 30/12/2022 12:18, Alexander Wetzel wrote:
> 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: c850e31f79f0 ("wifi: mac80211: add internal handler for wake_tx_queue")
> Signed-off-by: Alexander Wetzel <[email protected]>
> ---
> include/net/mac80211.h | 4 ----
> net/mac80211/debugfs_sta.c | 5 +++--
> net/mac80211/driver-ops.h | 2 +-
> net/mac80211/ieee80211_i.h | 2 +-
> net/mac80211/tx.c | 20 +++++++++++-------
> net/mac80211/util.c | 42 +++-----------------------------------
> 6 files changed, 21 insertions(+), 54 deletions(-)
>
> diff --git a/include/net/mac80211.h b/include/net/mac80211.h
> index 689da327ce2e..e3235b9c02c2 100644
> --- a/include/net/mac80211.h
> +++ b/include/net/mac80211.h
> @@ -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.
> @@ -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 */
> diff --git a/net/mac80211/debugfs_sta.c b/net/mac80211/debugfs_sta.c
> index 7a3d7893e19d..f1914bf39f0e 100644
> --- a/net/mac80211/debugfs_sta.c
> +++ b/net/mac80211/debugfs_sta.c
> @@ -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,
> @@ -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();
> diff --git a/net/mac80211/driver-ops.h b/net/mac80211/driver-ops.h
> index 809bad53e15b..5d13a3dfd366 100644
> --- a/net/mac80211/driver-ops.h
> +++ b/net/mac80211/driver-ops.h
> @@ -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;
> }
>
> diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
> index 63ff0d2524b6..d16606e84e22 100644
> --- a/net/mac80211/ieee80211_i.h
> +++ b/net/mac80211/ieee80211_i.h
> @@ -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,
> };
>
> /**
> diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
> index 2171cd1ca807..178043f84489 100644
> --- a/net/mac80211/tx.c
> +++ b/net/mac80211/tx.c
> @@ -3783,6 +3783,8 @@ 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);
>
> @@ -3790,16 +3792,20 @@ struct sk_buff *ieee80211_tx_dequeue(struct ieee80211_hw *hw,
> 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);
> diff --git a/net/mac80211/util.c b/net/mac80211/util.c
> index 6f5407038459..261ac667887f 100644
> --- a/net/mac80211/util.c
> +++ b/net/mac80211/util.c
> @@ -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;
> @@ -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;
>
> @@ -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;
>
> @@ -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;
>
> @@ -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);
>
> @@ -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,

Nice

Tested-by: Bryan O'Donoghue <[email protected]>

2023-01-10 19:39:40

by Bryan O'Donoghue

[permalink] [raw]