#include <linux/ieee80211.h>
#include <net/mac80211.h>
#include "ieee80211_i.h"
+#include "driver-ops.h"
#include "wme.h"
+/**
+ * DOC: TX aggregation
+ *
+ * Aggregation on the TX side requires setting the hardware flag
+ * %IEEE80211_HW_AMPDU_AGGREGATION as well as, if present, the @ampdu_queues
+ * hardware parameter to the number of hardware AMPDU queues. If there are no
+ * hardware queues then the driver will (currently) have to do all frame
+ * buffering.
+ *
+ * When TX aggregation is started by some subsystem (usually the rate control
+ * algorithm would be appropriate) by calling the
+ * ieee80211_start_tx_ba_session() function, the driver will be notified via
+ * its @ampdu_action function, with the %IEEE80211_AMPDU_TX_START action.
+ *
+ * In response to that, the driver is later required to call the
+ * ieee80211_start_tx_ba_cb() (or ieee80211_start_tx_ba_cb_irqsafe())
+ * function, which will start the aggregation session.
+ *
+ * Similarly, when the aggregation session is stopped by
+ * ieee80211_stop_tx_ba_session(), the driver's @ampdu_action function will
+ * be called with the action %IEEE80211_AMPDU_TX_STOP. In this case, the
+ * call must not fail, and the driver must later call ieee80211_stop_tx_ba_cb()
+ * (or ieee80211_stop_tx_ba_cb_irqsafe()).
+ */
+
static void ieee80211_send_addba_request(struct ieee80211_sub_if_data *sdata,
const u8 *da, u16 tid,
u8 dialog_token, u16 start_seq_num,
u16 agg_size, u16 timeout)
{
struct ieee80211_local *local = sdata->local;
- struct ieee80211_if_sta *ifsta = &sdata->u.sta;
struct sk_buff *skb;
struct ieee80211_mgmt *mgmt;
u16 capab;
if (sdata->vif.type == NL80211_IFTYPE_AP ||
sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
memcpy(mgmt->bssid, sdata->dev->dev_addr, ETH_ALEN);
- else
- memcpy(mgmt->bssid, ifsta->bssid, ETH_ALEN);
+ else if (sdata->vif.type == NL80211_IFTYPE_STATION)
+ memcpy(mgmt->bssid, sdata->u.mgd.bssid, ETH_ALEN);
mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
IEEE80211_STYPE_ACTION);
ieee80211_tx_skb(sdata, skb, 0);
}
+static int ___ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
+ enum ieee80211_back_parties initiator)
+{
+ struct ieee80211_local *local = sta->local;
+ int ret;
+ u8 *state;
+
+ state = &sta->ampdu_mlme.tid_state_tx[tid];
+
+ if (*state == HT_AGG_STATE_OPERATIONAL)
+ sta->ampdu_mlme.addba_req_num[tid] = 0;
+
+ *state = HT_AGG_STATE_REQ_STOP_BA_MSK |
+ (initiator << HT_AGG_STATE_INITIATOR_SHIFT);
+
+ ret = drv_ampdu_action(local, IEEE80211_AMPDU_TX_STOP,
+ &sta->sta, tid, NULL);
+
+ /* HW shall not deny going back to legacy */
+ if (WARN_ON(ret)) {
+ *state = HT_AGG_STATE_OPERATIONAL;
+ /*
+ * We may have pending packets get stuck in this case...
+ * Not bothering with a workaround for now.
+ */
+ }
+
+ return ret;
+}
+
/*
* After sending add Block Ack request we activated a timer until
* add Block Ack response will arrive from the recipient.
* flow in sta_info_create gives the TID as data, while the timer_to_id
* array gives the sta through container_of */
u16 tid = *(u8 *)data;
- struct sta_info *temp_sta = container_of((void *)data,
+ struct sta_info *sta = container_of((void *)data,
struct sta_info, timer_to_tid[tid]);
-
- struct ieee80211_local *local = temp_sta->local;
- struct ieee80211_hw *hw = &local->hw;
- struct sta_info *sta;
u8 *state;
- rcu_read_lock();
-
- sta = sta_info_get(local, temp_sta->sta.addr);
- if (!sta) {
- rcu_read_unlock();
- return;
- }
-
state = &sta->ampdu_mlme.tid_state_tx[tid];
+
/* check if the TID waits for addBA response */
spin_lock_bh(&sta->lock);
if (!(*state & HT_ADDBA_REQUESTED_MSK)) {
printk(KERN_DEBUG "timer expired on tid %d but we are not "
"expecting addBA response there", tid);
#endif
- goto timer_expired_exit;
+ return;
}
#ifdef CONFIG_MAC80211_HT_DEBUG
printk(KERN_DEBUG "addBA response timer expired on tid %d\n", tid);
#endif
- /* go through the state check in stop_BA_session */
- *state = HT_AGG_STATE_OPERATIONAL;
+ ___ieee80211_stop_tx_ba_session(sta, tid, WLAN_BACK_INITIATOR);
spin_unlock_bh(&sta->lock);
- ieee80211_stop_tx_ba_session(hw, temp_sta->sta.addr, tid,
- WLAN_BACK_INITIATOR);
+}
-timer_expired_exit:
- rcu_read_unlock();
+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;
+ u16 start_seq_num;
+
+ if (WARN_ON(!local->ops->ampdu_action))
+ return -EINVAL;
if ((tid >= STA_TID_NUM) || !(hw->flags & IEEE80211_HW_AMPDU_AGGREGATION))
return -EINVAL;
printk(KERN_DEBUG "Could not find the station\n");
#endif
ret = -ENOENT;
- goto exit;
+ goto unlock;
}
/*
sta->sdata->vif.type != NL80211_IFTYPE_AP_VLAN &&
sta->sdata->vif.type != NL80211_IFTYPE_AP) {
ret = -EINVAL;
- goto exit;
+ goto unlock;
+ }
+
+ if (test_sta_flags(sta, WLAN_STA_SUSPEND)) {
+#ifdef CONFIG_MAC80211_HT_DEBUG
+ printk(KERN_DEBUG "Suspend in progress. "
+ "Denying BA session request\n");
+#endif
+ ret = -EINVAL;
+ goto unlock;
}
spin_lock_bh(&sta->lock);
+ spin_lock(&local->ampdu_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) {
goto err_unlock_sta;
}
+ /*
+ * While we're asking the driver about the aggregation,
+ * stop the AC queue so that we don't have to worry
+ * about frames that came in while we were doing that,
+ * which would require us to put them to the AC pending
+ * afterwards which just makes the code more complex.
+ */
+ ieee80211_stop_queue_by_reason(
+ &local->hw, ieee80211_ac_from_tid(tid),
+ 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);
tid);
#endif
ret = -ENOMEM;
- goto err_unlock_sta;
+ goto err_wake_queue;
}
+
+ skb_queue_head_init(&sta->ampdu_mlme.tid_tx[tid]->pending);
+
/* Tx timer */
sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer.function =
sta_addba_resp_timer_expired;
(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];
- if (local->ops->ampdu_action)
- ret = local->ops->ampdu_action(hw, IEEE80211_AMPDU_TX_START,
- &sta->sta, tid, &start_seq_num);
+ ret = drv_ampdu_action(local, 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;
}
- /* Will put all the packets in the new SW queue */
- if (hw->ampdu_queues)
- ieee80211_requeue(local, ieee802_1d_to_ac[tid]);
+ /* Driver vetoed or OKed, but we can take packets again now */
+ ieee80211_wake_queue_by_reason(
+ &local->hw, ieee80211_ac_from_tid(tid),
+ IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
+
+ spin_unlock(&local->ampdu_lock);
spin_unlock_bh(&sta->lock);
/* send an addBA request */
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,
0x40, 5000);
+ sta->ampdu_mlme.addba_req_num[tid]++;
/* activate the timer for the recipient's addBA response */
sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer.expires =
jiffies + ADDBA_RESP_INTERVAL;
#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_wake_queue:
+ ieee80211_wake_queue_by_reason(
+ &local->hw, ieee80211_ac_from_tid(tid),
+ IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
+ err_unlock_sta:
+ spin_unlock(&local->ampdu_lock);
spin_unlock_bh(&sta->lock);
-exit:
+ unlock:
rcu_read_unlock();
return ret;
}
EXPORT_SYMBOL(ieee80211_start_tx_ba_session);
+/*
+ * splice packets from the STA's pending to the local pending,
+ * requires a call to ieee80211_agg_splice_finish and holding
+ * local->ampdu_lock across both calls.
+ */
+static void ieee80211_agg_splice_packets(struct ieee80211_local *local,
+ struct sta_info *sta, u16 tid)
+{
+ unsigned long flags;
+ u16 queue = ieee80211_ac_from_tid(tid);
+
+ ieee80211_stop_queue_by_reason(
+ &local->hw, queue,
+ IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
+
+ if (!skb_queue_empty(&sta->ampdu_mlme.tid_tx[tid]->pending)) {
+ spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
+ /* mark queue as pending, it is stopped already */
+ __set_bit(IEEE80211_QUEUE_STOP_REASON_PENDING,
+ &local->queue_stop_reasons[queue]);
+ /* copy over remaining packets */
+ skb_queue_splice_tail_init(
+ &sta->ampdu_mlme.tid_tx[tid]->pending,
+ &local->pending[queue]);
+ spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);
+ }
+}
+
+static void ieee80211_agg_splice_finish(struct ieee80211_local *local,
+ struct sta_info *sta, u16 tid)
+{
+ u16 queue = ieee80211_ac_from_tid(tid);
+
+ ieee80211_wake_queue_by_reason(
+ &local->hw, queue,
+ IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
+}
+
+/* caller must hold sta->lock */
+static void ieee80211_agg_tx_operational(struct ieee80211_local *local,
+ struct sta_info *sta, u16 tid)
+{
+#ifdef CONFIG_MAC80211_HT_DEBUG
+ printk(KERN_DEBUG "Aggregation is on for tid %d \n", tid);
+#endif
+
+ spin_lock(&local->ampdu_lock);
+ ieee80211_agg_splice_packets(local, sta, tid);
+ /*
+ * NB: we rely on sta->lock being taken in the TX
+ * processing here when adding to the pending queue,
+ * otherwise we could only change the state of the
+ * session to OPERATIONAL _here_.
+ */
+ ieee80211_agg_splice_finish(local, sta, tid);
+ spin_unlock(&local->ampdu_lock);
+
+ drv_ampdu_action(local, IEEE80211_AMPDU_TX_OPERATIONAL,
+ &sta->sta, tid, NULL);
+}
+
void ieee80211_start_tx_ba_cb(struct ieee80211_hw *hw, u8 *ra, u16 tid)
{
struct ieee80211_local *local = hw_to_local(hw);
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);
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 (*state == HT_AGG_STATE_OPERATIONAL)
+ ieee80211_agg_tx_operational(local, sta, tid);
+
+ out:
spin_unlock_bh(&sta->lock);
rcu_read_unlock();
}
EXPORT_SYMBOL(ieee80211_start_tx_ba_cb);
-
-int ieee80211_stop_tx_ba_session(struct ieee80211_hw *hw,
- u8 *ra, u16 tid,
- enum ieee80211_back_parties initiator)
+void ieee80211_start_tx_ba_cb_irqsafe(struct ieee80211_hw *hw,
+ const u8 *ra, u16 tid)
{
struct ieee80211_local *local = hw_to_local(hw);
- struct sta_info *sta;
- u8 *state;
- int ret = 0;
-
- if (tid >= STA_TID_NUM)
- return -EINVAL;
+ struct ieee80211_ra_tid *ra_tid;
+ struct sk_buff *skb = dev_alloc_skb(0);
- rcu_read_lock();
- sta = sta_info_get(local, ra);
- if (!sta) {
- rcu_read_unlock();
- return -ENOENT;
+ if (unlikely(!skb)) {
+#ifdef CONFIG_MAC80211_HT_DEBUG
+ if (net_ratelimit())
+ printk(KERN_WARNING "%s: Not enough memory, "
+ "dropping start BA session", skb->dev->name);
+#endif
+ return;
}
+ ra_tid = (struct ieee80211_ra_tid *) &skb->cb;
+ memcpy(&ra_tid->ra, ra, ETH_ALEN);
+ ra_tid->tid = tid;
+
+ skb->pkt_type = IEEE80211_ADDBA_MSG;
+ skb_queue_tail(&local->skb_queue, skb);
+ tasklet_schedule(&local->tasklet);
+}
+EXPORT_SYMBOL(ieee80211_start_tx_ba_cb_irqsafe);
+
+int __ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
+ enum ieee80211_back_parties initiator)
+{
+ u8 *state;
+ int ret;
/* check if the TID is in aggregation */
state = &sta->ampdu_mlme.tid_state_tx[tid];
if (*state != HT_AGG_STATE_OPERATIONAL) {
ret = -ENOENT;
- goto stop_BA_exit;
+ goto unlock;
}
#ifdef CONFIG_MAC80211_HT_DEBUG
printk(KERN_DEBUG "Tx BA session stop requested for %pM tid %u\n",
- ra, tid);
+ sta->sta.addr, tid);
#endif /* CONFIG_MAC80211_HT_DEBUG */
- if (hw->ampdu_queues)
- ieee80211_stop_queue(hw, sta->tid_to_tx_q[tid]);
+ ret = ___ieee80211_stop_tx_ba_session(sta, tid, initiator);
- *state = HT_AGG_STATE_REQ_STOP_BA_MSK |
- (initiator << HT_AGG_STATE_INITIATOR_SHIFT);
+ unlock:
+ spin_unlock_bh(&sta->lock);
+ return ret;
+}
+
+int ieee80211_stop_tx_ba_session(struct ieee80211_hw *hw,
+ u8 *ra, u16 tid,
+ enum ieee80211_back_parties initiator)
+{
+ struct ieee80211_local *local = hw_to_local(hw);
+ struct sta_info *sta;
+ int ret = 0;
+
+ if (WARN_ON(!local->ops->ampdu_action))
+ return -EINVAL;
- if (local->ops->ampdu_action)
- ret = local->ops->ampdu_action(hw, IEEE80211_AMPDU_TX_STOP,
- &sta->sta, tid, NULL);
+ if (tid >= STA_TID_NUM)
+ return -EINVAL;
- /* HW shall not deny going back to legacy */
- if (WARN_ON(ret)) {
- *state = HT_AGG_STATE_OPERATIONAL;
- if (hw->ampdu_queues)
- ieee80211_wake_queue(hw, sta->tid_to_tx_q[tid]);
- goto stop_BA_exit;
+ rcu_read_lock();
+ sta = sta_info_get(local, ra);
+ if (!sta) {
+ rcu_read_unlock();
+ return -ENOENT;
}
-stop_BA_exit:
- spin_unlock_bh(&sta->lock);
+ ret = __ieee80211_stop_tx_ba_session(sta, tid, initiator);
rcu_read_unlock();
return ret;
}
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
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);
-
- /* 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
- */
- netif_schedule_queue(netdev_get_tx_queue(local->mdev,
- agg_queue));
- }
spin_lock_bh(&sta->lock);
+ spin_lock(&local->ampdu_lock);
+
+ ieee80211_agg_splice_packets(local, sta, tid);
+
*state = HT_AGG_STATE_IDLE;
- sta->ampdu_mlme.addba_req_num[tid] = 0;
+ /* from now on packets are no longer put onto sta->pending */
kfree(sta->ampdu_mlme.tid_tx[tid]);
sta->ampdu_mlme.tid_tx[tid] = NULL;
+
+ ieee80211_agg_splice_finish(local, sta, tid);
+
+ spin_unlock(&local->ampdu_lock);
spin_unlock_bh(&sta->lock);
rcu_read_unlock();
}
EXPORT_SYMBOL(ieee80211_stop_tx_ba_cb);
-void ieee80211_start_tx_ba_cb_irqsafe(struct ieee80211_hw *hw,
- const u8 *ra, u16 tid)
-{
- struct ieee80211_local *local = hw_to_local(hw);
- struct ieee80211_ra_tid *ra_tid;
- struct sk_buff *skb = dev_alloc_skb(0);
-
- if (unlikely(!skb)) {
-#ifdef CONFIG_MAC80211_HT_DEBUG
- if (net_ratelimit())
- printk(KERN_WARNING "%s: Not enough memory, "
- "dropping start BA session", skb->dev->name);
-#endif
- return;
- }
- ra_tid = (struct ieee80211_ra_tid *) &skb->cb;
- memcpy(&ra_tid->ra, ra, ETH_ALEN);
- ra_tid->tid = tid;
-
- skb->pkt_type = IEEE80211_ADDBA_MSG;
- skb_queue_tail(&local->skb_queue, skb);
- tasklet_schedule(&local->tasklet);
-}
-EXPORT_SYMBOL(ieee80211_start_tx_ba_cb_irqsafe);
-
void ieee80211_stop_tx_ba_cb_irqsafe(struct ieee80211_hw *hw,
const u8 *ra, u16 tid)
{
}
EXPORT_SYMBOL(ieee80211_stop_tx_ba_cb_irqsafe);
+
void ieee80211_process_addba_resp(struct ieee80211_local *local,
struct sta_info *sta,
struct ieee80211_mgmt *mgmt,
size_t len)
{
- struct ieee80211_hw *hw = &local->hw;
- u16 capab;
- u16 tid, start_seq_num;
+ u16 capab, tid;
u8 *state;
capab = le16_to_cpu(mgmt->u.action.u.addba_resp.capab);
#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 (*state != curstate && *state == HT_AGG_STATE_OPERATIONAL)
+ ieee80211_agg_tx_operational(local, sta, tid);
- if (local->ops->ampdu_action) {
- (void)local->ops->ampdu_action(hw,
- IEEE80211_AMPDU_TX_RESUME,
- &sta->sta, tid, &start_seq_num);
- }
-#ifdef CONFIG_MAC80211_HT_DEBUG
- printk(KERN_DEBUG "Resuming TX aggregation for tid %d\n", tid);
-#endif /* CONFIG_MAC80211_HT_DEBUG */
- spin_unlock_bh(&sta->lock);
+ sta->ampdu_mlme.addba_req_num[tid] = 0;
} else {
- sta->ampdu_mlme.addba_req_num[tid]++;
- /* this will allow the state check in stop_BA_session */
- *state = HT_AGG_STATE_OPERATIONAL;
- spin_unlock_bh(&sta->lock);
- ieee80211_stop_tx_ba_session(hw, sta->sta.addr, tid,
- WLAN_BACK_INITIATOR);
+ ___ieee80211_stop_tx_ba_session(sta, tid, WLAN_BACK_INITIATOR);
}
+ spin_unlock_bh(&sta->lock);
}