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* Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi>
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* Copyright 2002-2005, Instant802 Networks, Inc.
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* Copyright 2005-2006, Devicescape Software, Inc.
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* Copyright 2006-2007 Jiri Benc <jbenc@suse.cz>
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* Copyright 2007, Michael Wu <flamingice@sourmilk.net>
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* Copyright 2007-2010, Intel Corporation
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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* DOC: RX A-MPDU aggregation
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* Aggregation on the RX side requires only implementing the
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* @ampdu_action callback that is invoked to start/stop any
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* block-ack sessions for RX aggregation.
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* When RX aggregation is started by the peer, the driver is
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* notified via @ampdu_action function, with the
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* %IEEE80211_AMPDU_RX_START action, and may reject the request
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* in which case a negative response is sent to the peer, if it
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* accepts it a positive response is sent.
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* While the session is active, the device/driver are required
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* to de-aggregate frames and pass them up one by one to mac80211,
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* which will handle the reorder buffer.
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* When the aggregation session is stopped again by the peer or
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* ourselves, the driver's @ampdu_action function will be called
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* with the action %IEEE80211_AMPDU_RX_STOP. In this case, the
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#include <linux/ieee80211.h>
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#include <linux/slab.h>
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#include <net/mac80211.h>
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#include "ieee80211_i.h"
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#include "driver-ops.h"
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static void ieee80211_free_tid_rx(struct rcu_head *h)
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struct tid_ampdu_rx *tid_rx =
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container_of(h, struct tid_ampdu_rx, rcu_head);
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for (i = 0; i < tid_rx->buf_size; i++)
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dev_kfree_skb(tid_rx->reorder_buf[i]);
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kfree(tid_rx->reorder_buf);
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kfree(tid_rx->reorder_time);
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void ___ieee80211_stop_rx_ba_session(struct sta_info *sta, u16 tid,
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u16 initiator, u16 reason, bool tx)
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struct ieee80211_local *local = sta->local;
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struct tid_ampdu_rx *tid_rx;
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lockdep_assert_held(&sta->ampdu_mlme.mtx);
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tid_rx = sta->ampdu_mlme.tid_rx[tid];
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rcu_assign_pointer(sta->ampdu_mlme.tid_rx[tid], NULL);
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#ifdef CONFIG_MAC80211_HT_DEBUG
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printk(KERN_DEBUG "Rx BA session stop requested for %pM tid %u\n",
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#endif /* CONFIG_MAC80211_HT_DEBUG */
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if (drv_ampdu_action(local, sta->sdata, IEEE80211_AMPDU_RX_STOP,
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&sta->sta, tid, NULL, 0))
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printk(KERN_DEBUG "HW problem - can not stop rx "
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"aggregation for tid %d\n", tid);
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/* check if this is a self generated aggregation halt */
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if (initiator == WLAN_BACK_RECIPIENT && tx)
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ieee80211_send_delba(sta->sdata, sta->sta.addr,
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del_timer_sync(&tid_rx->session_timer);
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del_timer_sync(&tid_rx->reorder_timer);
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call_rcu(&tid_rx->rcu_head, ieee80211_free_tid_rx);
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void __ieee80211_stop_rx_ba_session(struct sta_info *sta, u16 tid,
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u16 initiator, u16 reason, bool tx)
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mutex_lock(&sta->ampdu_mlme.mtx);
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___ieee80211_stop_rx_ba_session(sta, tid, initiator, reason, tx);
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mutex_unlock(&sta->ampdu_mlme.mtx);
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* After accepting the AddBA Request we activated a timer,
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* resetting it after each frame that arrives from the originator.
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static void sta_rx_agg_session_timer_expired(unsigned long data)
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/* not an elegant detour, but there is no choice as the timer passes
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* only one argument, and various sta_info are needed here, so init
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* flow in sta_info_create gives the TID as data, while the timer_to_id
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* array gives the sta through container_of */
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u8 *ptid = (u8 *)data;
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u8 *timer_to_id = ptid - *ptid;
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struct sta_info *sta = container_of(timer_to_id, struct sta_info,
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#ifdef CONFIG_MAC80211_HT_DEBUG
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printk(KERN_DEBUG "rx session timer expired on tid %d\n", (u16)*ptid);
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set_bit(*ptid, sta->ampdu_mlme.tid_rx_timer_expired);
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ieee80211_queue_work(&sta->local->hw, &sta->ampdu_mlme.work);
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static void sta_rx_agg_reorder_timer_expired(unsigned long data)
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u8 *ptid = (u8 *)data;
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u8 *timer_to_id = ptid - *ptid;
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struct sta_info *sta = container_of(timer_to_id, struct sta_info,
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ieee80211_release_reorder_timeout(sta, *ptid);
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static void ieee80211_send_addba_resp(struct ieee80211_sub_if_data *sdata, u8 *da, u16 tid,
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u8 dialog_token, u16 status, u16 policy,
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u16 buf_size, u16 timeout)
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struct ieee80211_local *local = sdata->local;
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struct ieee80211_mgmt *mgmt;
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skb = dev_alloc_skb(sizeof(*mgmt) + local->hw.extra_tx_headroom);
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printk(KERN_DEBUG "%s: failed to allocate buffer "
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"for addba resp frame\n", sdata->name);
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skb_reserve(skb, local->hw.extra_tx_headroom);
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mgmt = (struct ieee80211_mgmt *) skb_put(skb, 24);
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memcpy(mgmt->da, da, ETH_ALEN);
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memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
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if (sdata->vif.type == NL80211_IFTYPE_AP ||
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sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
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memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
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else if (sdata->vif.type == NL80211_IFTYPE_STATION)
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memcpy(mgmt->bssid, sdata->u.mgd.bssid, ETH_ALEN);
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mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
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IEEE80211_STYPE_ACTION);
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skb_put(skb, 1 + sizeof(mgmt->u.action.u.addba_resp));
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mgmt->u.action.category = WLAN_CATEGORY_BACK;
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mgmt->u.action.u.addba_resp.action_code = WLAN_ACTION_ADDBA_RESP;
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mgmt->u.action.u.addba_resp.dialog_token = dialog_token;
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capab = (u16)(policy << 1); /* bit 1 aggregation policy */
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capab |= (u16)(tid << 2); /* bit 5:2 TID number */
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capab |= (u16)(buf_size << 6); /* bit 15:6 max size of aggregation */
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mgmt->u.action.u.addba_resp.capab = cpu_to_le16(capab);
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mgmt->u.action.u.addba_resp.timeout = cpu_to_le16(timeout);
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mgmt->u.action.u.addba_resp.status = cpu_to_le16(status);
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ieee80211_tx_skb(sdata, skb);
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void ieee80211_process_addba_request(struct ieee80211_local *local,
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struct sta_info *sta,
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struct ieee80211_mgmt *mgmt,
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struct tid_ampdu_rx *tid_agg_rx;
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u16 capab, tid, timeout, ba_policy, buf_size, start_seq_num, status;
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int ret = -EOPNOTSUPP;
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/* extract session parameters from addba request frame */
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dialog_token = mgmt->u.action.u.addba_req.dialog_token;
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timeout = le16_to_cpu(mgmt->u.action.u.addba_req.timeout);
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le16_to_cpu(mgmt->u.action.u.addba_req.start_seq_num) >> 4;
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capab = le16_to_cpu(mgmt->u.action.u.addba_req.capab);
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ba_policy = (capab & IEEE80211_ADDBA_PARAM_POLICY_MASK) >> 1;
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tid = (capab & IEEE80211_ADDBA_PARAM_TID_MASK) >> 2;
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buf_size = (capab & IEEE80211_ADDBA_PARAM_BUF_SIZE_MASK) >> 6;
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status = WLAN_STATUS_REQUEST_DECLINED;
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if (test_sta_flags(sta, WLAN_STA_BLOCK_BA)) {
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#ifdef CONFIG_MAC80211_HT_DEBUG
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printk(KERN_DEBUG "Suspend in progress. "
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"Denying ADDBA request\n");
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/* sanity check for incoming parameters:
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* check if configuration can support the BA policy
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* and if buffer size does not exceeds max value */
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/* XXX: check own ht delayed BA capability?? */
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if (((ba_policy != 1) &&
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(!(sta->sta.ht_cap.cap & IEEE80211_HT_CAP_DELAY_BA))) ||
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(buf_size > IEEE80211_MAX_AMPDU_BUF)) {
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status = WLAN_STATUS_INVALID_QOS_PARAM;
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#ifdef CONFIG_MAC80211_HT_DEBUG
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printk(KERN_DEBUG "AddBA Req with bad params from "
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"%pM on tid %u. policy %d, buffer size %d\n",
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mgmt->sa, tid, ba_policy,
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#endif /* CONFIG_MAC80211_HT_DEBUG */
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/* determine default buffer size */
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buf_size = IEEE80211_MAX_AMPDU_BUF;
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/* make sure the size doesn't exceed the maximum supported by the hw */
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if (buf_size > local->hw.max_rx_aggregation_subframes)
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buf_size = local->hw.max_rx_aggregation_subframes;
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/* examine state machine */
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mutex_lock(&sta->ampdu_mlme.mtx);
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if (sta->ampdu_mlme.tid_rx[tid]) {
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#ifdef CONFIG_MAC80211_HT_DEBUG
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printk(KERN_DEBUG "unexpected AddBA Req from "
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#endif /* CONFIG_MAC80211_HT_DEBUG */
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/* prepare A-MPDU MLME for Rx aggregation */
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tid_agg_rx = kmalloc(sizeof(struct tid_ampdu_rx), GFP_KERNEL);
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#ifdef CONFIG_MAC80211_HT_DEBUG
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printk(KERN_ERR "allocate rx mlme to tid %d failed\n",
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spin_lock_init(&tid_agg_rx->reorder_lock);
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tid_agg_rx->session_timer.function = sta_rx_agg_session_timer_expired;
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tid_agg_rx->session_timer.data = (unsigned long)&sta->timer_to_tid[tid];
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init_timer(&tid_agg_rx->session_timer);
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/* rx reorder timer */
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tid_agg_rx->reorder_timer.function = sta_rx_agg_reorder_timer_expired;
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tid_agg_rx->reorder_timer.data = (unsigned long)&sta->timer_to_tid[tid];
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init_timer(&tid_agg_rx->reorder_timer);
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/* prepare reordering buffer */
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tid_agg_rx->reorder_buf =
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kcalloc(buf_size, sizeof(struct sk_buff *), GFP_KERNEL);
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tid_agg_rx->reorder_time =
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kcalloc(buf_size, sizeof(unsigned long), GFP_KERNEL);
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if (!tid_agg_rx->reorder_buf || !tid_agg_rx->reorder_time) {
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#ifdef CONFIG_MAC80211_HT_DEBUG
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printk(KERN_ERR "can not allocate reordering buffer "
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kfree(tid_agg_rx->reorder_buf);
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kfree(tid_agg_rx->reorder_time);
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ret = drv_ampdu_action(local, sta->sdata, IEEE80211_AMPDU_RX_START,
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&sta->sta, tid, &start_seq_num, 0);
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#ifdef CONFIG_MAC80211_HT_DEBUG
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printk(KERN_DEBUG "Rx A-MPDU request on tid %d result %d\n", tid, ret);
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#endif /* CONFIG_MAC80211_HT_DEBUG */
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kfree(tid_agg_rx->reorder_buf);
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kfree(tid_agg_rx->reorder_time);
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tid_agg_rx->dialog_token = dialog_token;
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tid_agg_rx->ssn = start_seq_num;
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tid_agg_rx->head_seq_num = start_seq_num;
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tid_agg_rx->buf_size = buf_size;
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tid_agg_rx->timeout = timeout;
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tid_agg_rx->stored_mpdu_num = 0;
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status = WLAN_STATUS_SUCCESS;
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/* activate it for RX */
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rcu_assign_pointer(sta->ampdu_mlme.tid_rx[tid], tid_agg_rx);
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mod_timer(&tid_agg_rx->session_timer, TU_TO_EXP_TIME(timeout));
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mutex_unlock(&sta->ampdu_mlme.mtx);
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ieee80211_send_addba_resp(sta->sdata, sta->sta.addr, tid,
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dialog_token, status, 1, buf_size, timeout);