Skip to content

Commit

Permalink
mac80211: fix aggregation for hardware with ampdu queues
Browse files Browse the repository at this point in the history 
Hardware with AMPDU queues currently has broken aggregation.

This patch fixes it by making all A-MPDUs go over the regular AC queues,
but keeping track of the hardware queues in mac80211. As a first rough
version, it actually stops the AC queue for extended periods of time,
which can be removed by adding buffering internal to mac80211, but is
currently not a huge problem because people rarely use multiple TIDs
that are in the same AC (and iwlwifi currently doesn't operate as AP).

This is a short-term fix, my current medium-term plan, which I hope to
execute soon as well, but am not sure can finish before .30, looks like
this:
 1) rework the internal queuing layer in mac80211 that we use for
    fragments if the driver stopped queue in the middle of a fragmented
    frame to be able to queue more frames at once (rather than just a
    single frame with its fragments)
 2) instead of stopping the entire AC queue, queue up the frames in a
    per-station/per-TID queue during aggregation session initiation,
    when the session has come up take all those frames and put them
    onto the queue from 1)
 3) push the ampdu queue layer abstraction this patch introduces in
    mac80211 into the driver, and remove the virtual queue stuff from
    mac80211 again

This plan will probably also affect ath9k in that mac80211 queues the
frames instead of passing them down, even when there are no ampdu queues.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
  • Loading branch information
Johannes Berg authored and John W. Linville committed Feb 27, 2009
1 parent f3734ee commit 96f5e66
Show file tree
Hide file tree
Showing 10 changed files with 241 additions and 258 deletions.
5 changes: 0 additions & 5 deletions include/net/mac80211.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1022,11 +1022,6 @@ static inline int ieee80211_num_regular_queues(struct ieee80211_hw *hw)
return hw->queues;
}

static inline int ieee80211_num_queues(struct ieee80211_hw *hw)
{
return hw->queues + hw->ampdu_queues;
}

static inline struct ieee80211_rate *
ieee80211_get_tx_rate(const struct ieee80211_hw *hw,
const struct ieee80211_tx_info *c)
Expand Down
186 changes: 126 additions & 60 deletions net/mac80211/agg-tx.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -132,9 +132,24 @@ static int ___ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,

state = &sta->ampdu_mlme.tid_state_tx[tid];

if (local->hw.ampdu_queues)
ieee80211_stop_queue(&local->hw, sta->tid_to_tx_q[tid]);
if (local->hw.ampdu_queues) {
if (initiator) {
/*
* Stop the AC queue to avoid issues where we send
* unaggregated frames already before the delba.
*/
ieee80211_stop_queue_by_reason(&local->hw,
local->hw.queues + sta->tid_to_tx_q[tid],
IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
}

/*
* Pretend the driver woke the queue, just in case
* it disabled it before the session was stopped.
*/
ieee80211_wake_queue(
&local->hw, local->hw.queues + sta->tid_to_tx_q[tid]);
}
*state = HT_AGG_STATE_REQ_STOP_BA_MSK |
(initiator << HT_AGG_STATE_INITIATOR_SHIFT);

Expand All @@ -144,8 +159,6 @@ static int ___ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
/* HW shall not deny going back to legacy */
if (WARN_ON(ret)) {
*state = HT_AGG_STATE_OPERATIONAL;
if (local->hw.ampdu_queues)
ieee80211_wake_queue(&local->hw, sta->tid_to_tx_q[tid]);
}

return ret;
Expand Down Expand Up @@ -189,14 +202,19 @@ static void sta_addba_resp_timer_expired(unsigned long data)
spin_unlock_bh(&sta->lock);
}

static inline int ieee80211_ac_from_tid(int tid)
{
return ieee802_1d_to_ac[tid & 7];
}

int ieee80211_start_tx_ba_session(struct ieee80211_hw *hw, u8 *ra, u16 tid)
{
struct ieee80211_local *local = hw_to_local(hw);
struct sta_info *sta;
struct ieee80211_sub_if_data *sdata;
u16 start_seq_num;
u8 *state;
int ret = 0;
int i, qn = -1, ret = 0;
u16 start_seq_num;

if (WARN_ON(!local->ops->ampdu_action))
return -EINVAL;
Expand All @@ -209,6 +227,13 @@ int ieee80211_start_tx_ba_session(struct ieee80211_hw *hw, u8 *ra, u16 tid)
ra, tid);
#endif /* CONFIG_MAC80211_HT_DEBUG */

if (hw->ampdu_queues && ieee80211_ac_from_tid(tid) == 0) {
#ifdef CONFIG_MAC80211_HT_DEBUG
printk(KERN_DEBUG "rejecting on voice AC\n");
#endif
return -EINVAL;
}

rcu_read_lock();

sta = sta_info_get(local, ra);
Expand All @@ -217,7 +242,7 @@ int ieee80211_start_tx_ba_session(struct ieee80211_hw *hw, u8 *ra, u16 tid)
printk(KERN_DEBUG "Could not find the station\n");
#endif
ret = -ENOENT;
goto exit;
goto unlock;
}

/*
Expand All @@ -230,11 +255,13 @@ int ieee80211_start_tx_ba_session(struct ieee80211_hw *hw, u8 *ra, u16 tid)
sta->sdata->vif.type != NL80211_IFTYPE_AP_VLAN &&
sta->sdata->vif.type != NL80211_IFTYPE_AP) {
ret = -EINVAL;
goto exit;
goto unlock;
}

spin_lock_bh(&sta->lock);

sdata = sta->sdata;

/* we have tried too many times, receiver does not want A-MPDU */
if (sta->ampdu_mlme.addba_req_num[tid] > HT_AGG_MAX_RETRIES) {
ret = -EBUSY;
Expand All @@ -252,6 +279,42 @@ int ieee80211_start_tx_ba_session(struct ieee80211_hw *hw, u8 *ra, u16 tid)
goto err_unlock_sta;
}

if (hw->ampdu_queues) {
spin_lock(&local->queue_stop_reason_lock);
/* reserve a new queue for this session */
for (i = 0; i < local->hw.ampdu_queues; i++) {
if (local->ampdu_ac_queue[i] < 0) {
qn = i;
local->ampdu_ac_queue[qn] =
ieee80211_ac_from_tid(tid);
break;
}
}
spin_unlock(&local->queue_stop_reason_lock);

if (qn < 0) {
#ifdef CONFIG_MAC80211_HT_DEBUG
printk(KERN_DEBUG "BA request denied - "
"queue unavailable for tid %d\n", tid);
#endif /* CONFIG_MAC80211_HT_DEBUG */
ret = -ENOSPC;
goto err_unlock_sta;
}

/*
* If we successfully allocate the session, we can't have
* anything going on on the queue this TID maps into, so
* stop it for now. This is a "virtual" stop using the same
* mechanism that drivers will use.
*
* XXX: queue up frames for this session in the sta_info
* struct instead to avoid hitting all other STAs.
*/
ieee80211_stop_queue_by_reason(
&local->hw, hw->queues + qn,
IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
}

/* prepare A-MPDU MLME for Tx aggregation */
sta->ampdu_mlme.tid_tx[tid] =
kmalloc(sizeof(struct tid_ampdu_tx), GFP_ATOMIC);
Expand All @@ -262,58 +325,35 @@ int ieee80211_start_tx_ba_session(struct ieee80211_hw *hw, u8 *ra, u16 tid)
tid);
#endif
ret = -ENOMEM;
goto err_unlock_sta;
goto err_return_queue;
}

/* Tx timer */
sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer.function =
sta_addba_resp_timer_expired;
sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer.data =
(unsigned long)&sta->timer_to_tid[tid];
init_timer(&sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer);

if (hw->ampdu_queues) {
/* create a new queue for this aggregation */
ret = ieee80211_ht_agg_queue_add(local, sta, tid);

/* case no queue is available to aggregation
* don't switch to aggregation */
if (ret) {
#ifdef CONFIG_MAC80211_HT_DEBUG
printk(KERN_DEBUG "BA request denied - "
"queue unavailable for tid %d\n", tid);
#endif /* CONFIG_MAC80211_HT_DEBUG */
goto err_unlock_queue;
}
}
sdata = sta->sdata;

/* Ok, the Addba frame hasn't been sent yet, but if the driver calls the
* call back right away, it must see that the flow has begun */
*state |= HT_ADDBA_REQUESTED_MSK;

/* This is slightly racy because the queue isn't stopped */
start_seq_num = sta->tid_seq[tid];

ret = local->ops->ampdu_action(hw, IEEE80211_AMPDU_TX_START,
&sta->sta, tid, &start_seq_num);

if (ret) {
/* No need to requeue the packets in the agg queue, since we
* held the tx lock: no packet could be enqueued to the newly
* allocated queue */
if (hw->ampdu_queues)
ieee80211_ht_agg_queue_remove(local, sta, tid, 0);
#ifdef CONFIG_MAC80211_HT_DEBUG
printk(KERN_DEBUG "BA request denied - HW unavailable for"
" tid %d\n", tid);
#endif /* CONFIG_MAC80211_HT_DEBUG */
*state = HT_AGG_STATE_IDLE;
goto err_unlock_queue;
goto err_free;
}
sta->tid_to_tx_q[tid] = qn;

/* Will put all the packets in the new SW queue */
if (hw->ampdu_queues)
ieee80211_requeue(local, ieee802_1d_to_ac[tid]);
spin_unlock_bh(&sta->lock);

/* send an addBA request */
Expand All @@ -322,7 +362,6 @@ int ieee80211_start_tx_ba_session(struct ieee80211_hw *hw, u8 *ra, u16 tid)
sta->ampdu_mlme.dialog_token_allocator;
sta->ampdu_mlme.tid_tx[tid]->ssn = start_seq_num;


ieee80211_send_addba_request(sta->sdata, ra, tid,
sta->ampdu_mlme.tid_tx[tid]->dialog_token,
sta->ampdu_mlme.tid_tx[tid]->ssn,
Expand All @@ -334,15 +373,24 @@ int ieee80211_start_tx_ba_session(struct ieee80211_hw *hw, u8 *ra, u16 tid)
#ifdef CONFIG_MAC80211_HT_DEBUG
printk(KERN_DEBUG "activated addBA response timer on tid %d\n", tid);
#endif
goto exit;
goto unlock;

err_unlock_queue:
err_free:
kfree(sta->ampdu_mlme.tid_tx[tid]);
sta->ampdu_mlme.tid_tx[tid] = NULL;
ret = -EBUSY;
err_unlock_sta:
err_return_queue:
if (qn >= 0) {
/* We failed, so start queue again right away. */
ieee80211_wake_queue_by_reason(hw, hw->queues + qn,
IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
/* give queue back to pool */
spin_lock(&local->queue_stop_reason_lock);
local->ampdu_ac_queue[qn] = -1;
spin_unlock(&local->queue_stop_reason_lock);
}
err_unlock_sta:
spin_unlock_bh(&sta->lock);
exit:
unlock:
rcu_read_unlock();
return ret;
}
Expand Down Expand Up @@ -375,7 +423,7 @@ void ieee80211_start_tx_ba_cb(struct ieee80211_hw *hw, u8 *ra, u16 tid)
state = &sta->ampdu_mlme.tid_state_tx[tid];
spin_lock_bh(&sta->lock);

if (!(*state & HT_ADDBA_REQUESTED_MSK)) {
if (WARN_ON(!(*state & HT_ADDBA_REQUESTED_MSK))) {
#ifdef CONFIG_MAC80211_HT_DEBUG
printk(KERN_DEBUG "addBA was not requested yet, state is %d\n",
*state);
Expand All @@ -385,17 +433,27 @@ void ieee80211_start_tx_ba_cb(struct ieee80211_hw *hw, u8 *ra, u16 tid)
return;
}

WARN_ON_ONCE(*state & HT_ADDBA_DRV_READY_MSK);
if (WARN_ON(*state & HT_ADDBA_DRV_READY_MSK))
goto out;

*state |= HT_ADDBA_DRV_READY_MSK;

if (*state == HT_AGG_STATE_OPERATIONAL) {
#ifdef CONFIG_MAC80211_HT_DEBUG
printk(KERN_DEBUG "Aggregation is on for tid %d \n", tid);
#endif
if (hw->ampdu_queues)
ieee80211_wake_queue(hw, sta->tid_to_tx_q[tid]);
if (hw->ampdu_queues) {
/*
* Wake up this queue, we stopped it earlier,
* this will in turn wake the entire AC.
*/
ieee80211_wake_queue_by_reason(hw,
hw->queues + sta->tid_to_tx_q[tid],
IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
}
}

out:
spin_unlock_bh(&sta->lock);
rcu_read_unlock();
}
Expand Down Expand Up @@ -485,7 +543,6 @@ void ieee80211_stop_tx_ba_cb(struct ieee80211_hw *hw, u8 *ra, u8 tid)
struct ieee80211_local *local = hw_to_local(hw);
struct sta_info *sta;
u8 *state;
int agg_queue;

if (tid >= STA_TID_NUM) {
#ifdef CONFIG_MAC80211_HT_DEBUG
Expand Down Expand Up @@ -527,19 +584,19 @@ void ieee80211_stop_tx_ba_cb(struct ieee80211_hw *hw, u8 *ra, u8 tid)
ieee80211_send_delba(sta->sdata, ra, tid,
WLAN_BACK_INITIATOR, WLAN_REASON_QSTA_NOT_USE);

if (hw->ampdu_queues) {
agg_queue = sta->tid_to_tx_q[tid];
ieee80211_ht_agg_queue_remove(local, sta, tid, 1);
spin_lock_bh(&sta->lock);

/* We just requeued the all the frames that were in the
* removed queue, and since we might miss a softirq we do
* netif_schedule_queue. ieee80211_wake_queue is not used
* here as this queue is not necessarily stopped
if (*state & HT_AGG_STATE_INITIATOR_MSK &&
hw->ampdu_queues) {
/*
* Wake up this queue, we stopped it earlier,
* this will in turn wake the entire AC.
*/
netif_schedule_queue(netdev_get_tx_queue(local->mdev,
agg_queue));
ieee80211_wake_queue_by_reason(hw,
hw->queues + sta->tid_to_tx_q[tid],
IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
}
spin_lock_bh(&sta->lock);

*state = HT_AGG_STATE_IDLE;
sta->ampdu_mlme.addba_req_num[tid] = 0;
kfree(sta->ampdu_mlme.tid_tx[tid]);
Expand Down Expand Up @@ -613,12 +670,21 @@ void ieee80211_process_addba_resp(struct ieee80211_local *local,
#endif /* CONFIG_MAC80211_HT_DEBUG */
if (le16_to_cpu(mgmt->u.action.u.addba_resp.status)
== WLAN_STATUS_SUCCESS) {
u8 curstate = *state;

*state |= HT_ADDBA_RECEIVED_MSK;
sta->ampdu_mlme.addba_req_num[tid] = 0;

if (*state == HT_AGG_STATE_OPERATIONAL &&
local->hw.ampdu_queues)
ieee80211_wake_queue(hw, sta->tid_to_tx_q[tid]);
if (hw->ampdu_queues && *state != curstate &&
*state == HT_AGG_STATE_OPERATIONAL) {
/*
* Wake up this queue, we stopped it earlier,
* this will in turn wake the entire AC.
*/
ieee80211_wake_queue_by_reason(hw,
hw->queues + sta->tid_to_tx_q[tid],
IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
}
sta->ampdu_mlme.addba_req_num[tid] = 0;

if (local->ops->ampdu_action) {
(void)local->ops->ampdu_action(hw,
Expand Down
20 changes: 14 additions & 6 deletions net/mac80211/ieee80211_i.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -564,12 +564,10 @@ enum {
enum queue_stop_reason {
IEEE80211_QUEUE_STOP_REASON_DRIVER,
IEEE80211_QUEUE_STOP_REASON_PS,
IEEE80211_QUEUE_STOP_REASON_CSA
IEEE80211_QUEUE_STOP_REASON_CSA,
IEEE80211_QUEUE_STOP_REASON_AGGREGATION,
};

/* maximum number of hardware queues we support. */
#define QD_MAX_QUEUES (IEEE80211_MAX_AMPDU_QUEUES + IEEE80211_MAX_QUEUES)

struct ieee80211_master_priv {
struct ieee80211_local *local;
};
Expand All @@ -582,9 +580,15 @@ struct ieee80211_local {

const struct ieee80211_ops *ops;

unsigned long queue_pool[BITS_TO_LONGS(QD_MAX_QUEUES)];
unsigned long queue_stop_reasons[IEEE80211_MAX_QUEUES];
/* AC queue corresponding to each AMPDU queue */
s8 ampdu_ac_queue[IEEE80211_MAX_AMPDU_QUEUES];
unsigned int amdpu_ac_stop_refcnt[IEEE80211_MAX_AMPDU_QUEUES];

unsigned long queue_stop_reasons[IEEE80211_MAX_QUEUES +
IEEE80211_MAX_AMPDU_QUEUES];
/* also used to protect ampdu_ac_queue and amdpu_ac_stop_refcnt */
spinlock_t queue_stop_reason_lock;

struct net_device *mdev; /* wmaster# - "master" 802.11 device */
int open_count;
int monitors, cooked_mntrs;
Expand Down Expand Up @@ -1042,6 +1046,10 @@ void ieee80211_wake_queues_by_reason(struct ieee80211_hw *hw,
enum queue_stop_reason reason);
void ieee80211_stop_queues_by_reason(struct ieee80211_hw *hw,
enum queue_stop_reason reason);
void ieee80211_wake_queue_by_reason(struct ieee80211_hw *hw, int queue,
enum queue_stop_reason reason);
void ieee80211_stop_queue_by_reason(struct ieee80211_hw *hw, int queue,
enum queue_stop_reason reason);

#ifdef CONFIG_MAC80211_NOINLINE
#define debug_noinline noinline
Expand Down
Loading

0 comments on commit 96f5e66

Please sign in to comment.