/* * HT handling * * Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi> * Copyright 2002-2005, Instant802 Networks, Inc. * Copyright 2005-2006, Devicescape Software, Inc. * Copyright 2006-2007 Jiri Benc <jbenc@suse.cz> * Copyright 2007, Michael Wu <flamingice@sourmilk.net> * Copyright 2007-2009, Intel Corporation * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #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 sk_buff *skb; struct ieee80211_mgmt *mgmt; u16 capab; skb = dev_alloc_skb(sizeof(*mgmt) + local->hw.extra_tx_headroom); if (!skb) { printk(KERN_ERR "%s: failed to allocate buffer " "for addba request frame\n", sdata->dev->name); return; } skb_reserve(skb, local->hw.extra_tx_headroom); mgmt = (struct ieee80211_mgmt *) skb_put(skb, 24); memset(mgmt, 0, 24); memcpy(mgmt->da, da, ETH_ALEN); memcpy(mgmt->sa, sdata->dev->dev_addr, ETH_ALEN); if (sdata->vif.type == NL80211_IFTYPE_AP || sdata->vif.type == NL80211_IFTYPE_AP_VLAN) memcpy(mgmt->bssid, sdata->dev->dev_addr, 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); skb_put(skb, 1 + sizeof(mgmt->u.action.u.addba_req)); mgmt->u.action.category = WLAN_CATEGORY_BACK; mgmt->u.action.u.addba_req.action_code = WLAN_ACTION_ADDBA_REQ; mgmt->u.action.u.addba_req.dialog_token = dialog_token; capab = (u16)(1 << 1); /* bit 1 aggregation policy */ capab |= (u16)(tid << 2); /* bit 5:2 TID number */ capab |= (u16)(agg_size << 6); /* bit 15:6 max size of aggergation */ mgmt->u.action.u.addba_req.capab = cpu_to_le16(capab); mgmt->u.action.u.addba_req.timeout = cpu_to_le16(timeout); mgmt->u.action.u.addba_req.start_seq_num = cpu_to_le16(start_seq_num << 4); ieee80211_tx_skb(sdata, skb, 1); } void ieee80211_send_bar(struct ieee80211_sub_if_data *sdata, u8 *ra, u16 tid, u16 ssn) { struct ieee80211_local *local = sdata->local; struct sk_buff *skb; struct ieee80211_bar *bar; u16 bar_control = 0; skb = dev_alloc_skb(sizeof(*bar) + local->hw.extra_tx_headroom); if (!skb) { printk(KERN_ERR "%s: failed to allocate buffer for " "bar frame\n", sdata->dev->name); return; } skb_reserve(skb, local->hw.extra_tx_headroom); bar = (struct ieee80211_bar *)skb_put(skb, sizeof(*bar)); memset(bar, 0, sizeof(*bar)); bar->frame_control = cpu_to_le16(IEEE80211_FTYPE_CTL | IEEE80211_STYPE_BACK_REQ); memcpy(bar->ra, ra, ETH_ALEN); memcpy(bar->ta, sdata->dev->dev_addr, ETH_ALEN); bar_control |= (u16)IEEE80211_BAR_CTRL_ACK_POLICY_NORMAL; bar_control |= (u16)IEEE80211_BAR_CTRL_CBMTID_COMPRESSED_BA; bar_control |= (u16)(tid << 12); bar->control = cpu_to_le16(bar_control); bar->start_seq_num = cpu_to_le16(ssn); 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. * If this timer expires sta_addba_resp_timer_expired will be executed. */ static void sta_addba_resp_timer_expired(unsigned long data) { /* not an elegant detour, but there is no choice as the timer passes * only one argument, and both sta_info and TID are needed, so init * 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 *sta = container_of((void *)data, struct sta_info, timer_to_tid[tid]); u8 *state; 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)) { spin_unlock_bh(&sta->lock); *state = HT_AGG_STATE_IDLE; #ifdef CONFIG_MAC80211_HT_DEBUG printk(KERN_DEBUG "timer expired on tid %d but we are not " "expecting addBA response there", tid); #endif return; } #ifdef CONFIG_MAC80211_HT_DEBUG printk(KERN_DEBUG "addBA response timer expired on tid %d\n", tid); #endif ___ieee80211_stop_tx_ba_session(sta, tid, WLAN_BACK_INITIATOR); 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; 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; #ifdef CONFIG_MAC80211_HT_DEBUG printk(KERN_DEBUG "Open BA session requested for %pM tid %u\n", ra, tid); #endif /* CONFIG_MAC80211_HT_DEBUG */ rcu_read_lock(); sta = sta_info_get(local, ra); if (!sta) { #ifdef CONFIG_MAC80211_HT_DEBUG printk(KERN_DEBUG "Could not find the station\n"); #endif ret = -ENOENT; goto unlock; } /* * The aggregation code is not prepared to handle * anything but STA/AP due to the BSSID handling. * IBSS could work in the code but isn't supported * by drivers or the standard. */ if (sta->sdata->vif.type != NL80211_IFTYPE_STATION && sta->sdata->vif.type != NL80211_IFTYPE_AP_VLAN && sta->sdata->vif.type != NL80211_IFTYPE_AP) { ret = -EINVAL; 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) { ret = -EBUSY; goto err_unlock_sta; } state = &sta->ampdu_mlme.tid_state_tx[tid]; /* check if the TID is not in aggregation flow already */ if (*state != HT_AGG_STATE_IDLE) { #ifdef CONFIG_MAC80211_HT_DEBUG printk(KERN_DEBUG "BA request denied - session is not " "idle on tid %u\n", tid); #endif /* CONFIG_MAC80211_HT_DEBUG */ ret = -EAGAIN; 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); if (!sta->ampdu_mlme.tid_tx[tid]) { #ifdef CONFIG_MAC80211_HT_DEBUG if (net_ratelimit()) printk(KERN_ERR "allocate tx mlme to tid %d failed\n", tid); #endif ret = -ENOMEM; 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; 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); /* 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; start_seq_num = sta->tid_seq[tid]; ret = drv_ampdu_action(local, IEEE80211_AMPDU_TX_START, &sta->sta, tid, &start_seq_num); if (ret) { #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_free; } /* 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]->dialog_token = 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; add_timer(&sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer); #ifdef CONFIG_MAC80211_HT_DEBUG printk(KERN_DEBUG "activated addBA response timer on tid %d\n", tid); #endif goto unlock; err_free: kfree(sta->ampdu_mlme.tid_tx[tid]); sta->ampdu_mlme.tid_tx[tid] = NULL; 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); 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 (!(sta->ampdu_mlme.tid_state_tx[tid] & HT_ADDBA_REQUESTED_MSK)) return; if (WARN(!sta->ampdu_mlme.tid_tx[tid], "TID %d gone but expected when splicing aggregates from" "the pending queue\n", tid)) return; 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); struct sta_info *sta; u8 *state; if (tid >= STA_TID_NUM) { #ifdef CONFIG_MAC80211_HT_DEBUG printk(KERN_DEBUG "Bad TID value: tid = %d (>= %d)\n", tid, STA_TID_NUM); #endif return; } rcu_read_lock(); sta = sta_info_get(local, ra); if (!sta) { rcu_read_unlock(); #ifdef CONFIG_MAC80211_HT_DEBUG printk(KERN_DEBUG "Could not find station: %pM\n", ra); #endif return; } state = &sta->ampdu_mlme.tid_state_tx[tid]; spin_lock_bh(&sta->lock); 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); #endif spin_unlock_bh(&sta->lock); rcu_read_unlock(); return; } if (WARN_ON(*state & HT_ADDBA_DRV_READY_MSK)) goto out; *state |= HT_ADDBA_DRV_READY_MSK; 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); 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); 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]; spin_lock_bh(&sta->lock); if (*state != HT_AGG_STATE_OPERATIONAL) { ret = -ENOENT; goto unlock; } #ifdef CONFIG_MAC80211_HT_DEBUG printk(KERN_DEBUG "Tx BA session stop requested for %pM tid %u\n", sta->sta.addr, tid); #endif /* CONFIG_MAC80211_HT_DEBUG */ ret = ___ieee80211_stop_tx_ba_session(sta, tid, initiator); 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 (tid >= STA_TID_NUM) return -EINVAL; rcu_read_lock(); sta = sta_info_get(local, ra); if (!sta) { rcu_read_unlock(); return -ENOENT; } ret = __ieee80211_stop_tx_ba_session(sta, tid, initiator); rcu_read_unlock(); return ret; } EXPORT_SYMBOL(ieee80211_stop_tx_ba_session); 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; if (tid >= STA_TID_NUM) { #ifdef CONFIG_MAC80211_HT_DEBUG printk(KERN_DEBUG "Bad TID value: tid = %d (>= %d)\n", tid, STA_TID_NUM); #endif return; } #ifdef CONFIG_MAC80211_HT_DEBUG printk(KERN_DEBUG "Stopping Tx BA session for %pM tid %d\n", ra, tid); #endif /* CONFIG_MAC80211_HT_DEBUG */ rcu_read_lock(); sta = sta_info_get(local, ra); if (!sta) { #ifdef CONFIG_MAC80211_HT_DEBUG printk(KERN_DEBUG "Could not find station: %pM\n", ra); #endif rcu_read_unlock(); return; } state = &sta->ampdu_mlme.tid_state_tx[tid]; /* NOTE: no need to use sta->lock in this state check, as * ieee80211_stop_tx_ba_session will let only one stop call to * pass through per sta/tid */ if ((*state & HT_AGG_STATE_REQ_STOP_BA_MSK) == 0) { #ifdef CONFIG_MAC80211_HT_DEBUG printk(KERN_DEBUG "unexpected callback to A-MPDU stop\n"); #endif rcu_read_unlock(); return; } if (*state & HT_AGG_STATE_INITIATOR_MSK) ieee80211_send_delba(sta->sdata, ra, tid, WLAN_BACK_INITIATOR, WLAN_REASON_QSTA_NOT_USE); spin_lock_bh(&sta->lock); spin_lock(&local->ampdu_lock); ieee80211_agg_splice_packets(local, sta, tid); *state = HT_AGG_STATE_IDLE; /* 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_stop_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 stop 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_DELBA_MSG; skb_queue_tail(&local->skb_queue, skb); tasklet_schedule(&local->tasklet); } 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) { u16 capab, tid; u8 *state; capab = le16_to_cpu(mgmt->u.action.u.addba_resp.capab); tid = (capab & IEEE80211_ADDBA_PARAM_TID_MASK) >> 2; state = &sta->ampdu_mlme.tid_state_tx[tid]; spin_lock_bh(&sta->lock); if (!(*state & HT_ADDBA_REQUESTED_MSK)) { spin_unlock_bh(&sta->lock); return; } if (mgmt->u.action.u.addba_resp.dialog_token != sta->ampdu_mlme.tid_tx[tid]->dialog_token) { spin_unlock_bh(&sta->lock); #ifdef CONFIG_MAC80211_HT_DEBUG printk(KERN_DEBUG "wrong addBA response token, tid %d\n", tid); #endif /* CONFIG_MAC80211_HT_DEBUG */ return; } del_timer_sync(&sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer); #ifdef CONFIG_MAC80211_HT_DEBUG printk(KERN_DEBUG "switched off addBA timer for tid %d \n", tid); #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; if (*state != curstate && *state == HT_AGG_STATE_OPERATIONAL) ieee80211_agg_tx_operational(local, sta, tid); sta->ampdu_mlme.addba_req_num[tid] = 0; } else { ___ieee80211_stop_tx_ba_session(sta, tid, WLAN_BACK_INITIATOR); } spin_unlock_bh(&sta->lock); }