net/mac80211/agg-tx.c

   1 /*
   2  * HT handling
   3  *
   4  * Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi>
   5  * Copyright 2002-2005, Instant802 Networks, Inc.
   6  * Copyright 2005-2006, Devicescape Software, Inc.
   7  * Copyright 2006-2007  Jiri Benc <jbenc@suse.cz>
   8  * Copyright 2007, Michael Wu <flamingice@sourmilk.net>
   9  * Copyright 2007-2010, Intel Corporation
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License version 2 as
  13  * published by the Free Software Foundation.
  14  */
  15
  16 #include <linux/ieee80211.h>
  17 #include <linux/slab.h>
  18 #include <net/mac80211.h>
  19 #include "ieee80211_i.h"
  20 #include "driver-ops.h"
  21 #include "wme.h"
  22
  23 /**
  24  * DOC: TX A-MPDU aggregation
  25  *
  26  * Aggregation on the TX side requires setting the hardware flag
  27  * %IEEE80211_HW_AMPDU_AGGREGATION. The driver will then be handed
  28  * packets with a flag indicating A-MPDU aggregation. The driver
  29  * or device is responsible for actually aggregating the frames,
  30  * as well as deciding how many and which to aggregate.
  31  *
  32  * When TX aggregation is started by some subsystem (usually the rate
  33  * control algorithm would be appropriate) by calling the
  34  * ieee80211_start_tx_ba_session() function, the driver will be
  35  * notified via its @ampdu_action function, with the
  36  * %IEEE80211_AMPDU_TX_START action.
  37  *
  38  * In response to that, the driver is later required to call the
  39  * ieee80211_start_tx_ba_cb_irqsafe() function, which will really
  40  * start the aggregation session after the peer has also responded.
  41  * If the peer responds negatively, the session will be stopped
  42  * again right away. Note that it is possible for the aggregation
  43  * session to be stopped before the driver has indicated that it
  44  * is done setting it up, in which case it must not indicate the
  45  * setup completion.
  46  *
  47  * Also note that, since we also need to wait for a response from
  48  * the peer, the driver is notified of the completion of the
  49  * handshake by the %IEEE80211_AMPDU_TX_OPERATIONAL action to the
  50  * @ampdu_action callback.
  51  *
  52  * Similarly, when the aggregation session is stopped by the peer
  53  * or something calling ieee80211_stop_tx_ba_session(), the driver's
  54  * @ampdu_action function will be called with the action
  55  * %IEEE80211_AMPDU_TX_STOP. In this case, the call must not fail,
  56  * and the driver must later call ieee80211_stop_tx_ba_cb_irqsafe().
  57  */
  58
  59 static void ieee80211_send_addba_request(struct ieee80211_sub_if_data *sdata,
  60                                          const u8 *da, u16 tid,
  61                                          u8 dialog_token, u16 start_seq_num,
  62                                          u16 agg_size, u16 timeout)
  63 {
  64         struct ieee80211_local *local = sdata->local;
  65         struct sk_buff *skb;
  66         struct ieee80211_mgmt *mgmt;
  67         u16 capab;
  68
  69         skb = dev_alloc_skb(sizeof(*mgmt) + local->hw.extra_tx_headroom);
  70
  71         if (!skb)
  72                 return;
  73
  74         skb_reserve(skb, local->hw.extra_tx_headroom);
  75         mgmt = (struct ieee80211_mgmt *) skb_put(skb, 24);
  76         memset(mgmt, 0, 24);
  77         memcpy(mgmt->da, da, ETH_ALEN);
  78         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
  79         if (sdata->vif.type == NL80211_IFTYPE_AP ||
  80             sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
  81                 memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
  82         else if (sdata->vif.type == NL80211_IFTYPE_STATION)
  83                 memcpy(mgmt->bssid, sdata->u.mgd.bssid, ETH_ALEN);
  84
  85         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
  86                                           IEEE80211_STYPE_ACTION);
  87
  88         skb_put(skb, 1 + sizeof(mgmt->u.action.u.addba_req));
  89
  90         mgmt->u.action.category = WLAN_CATEGORY_BACK;
  91         mgmt->u.action.u.addba_req.action_code = WLAN_ACTION_ADDBA_REQ;
  92
  93         mgmt->u.action.u.addba_req.dialog_token = dialog_token;
  94         capab = (u16)(1 << 1);          /* bit 1 aggregation policy */
  95         capab |= (u16)(tid << 2);       /* bit 5:2 TID number */
  96         capab |= (u16)(agg_size << 6);  /* bit 15:6 max size of aggergation */
  97
  98         mgmt->u.action.u.addba_req.capab = cpu_to_le16(capab);
  99
 100         mgmt->u.action.u.addba_req.timeout = cpu_to_le16(timeout);
 101         mgmt->u.action.u.addba_req.start_seq_num =
 102                                         cpu_to_le16(start_seq_num << 4);
 103
 104         ieee80211_tx_skb(sdata, skb);
 105 }
 106
 107 void ieee80211_send_bar(struct ieee80211_vif *vif, u8 *ra, u16 tid, u16 ssn)
 108 {
 109         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 110         struct ieee80211_local *local = sdata->local;
 111         struct sk_buff *skb;
 112         struct ieee80211_bar *bar;
 113         u16 bar_control = 0;
 114
 115         skb = dev_alloc_skb(sizeof(*bar) + local->hw.extra_tx_headroom);
 116         if (!skb)
 117                 return;
 118
 119         skb_reserve(skb, local->hw.extra_tx_headroom);
 120         bar = (struct ieee80211_bar *)skb_put(skb, sizeof(*bar));
 121         memset(bar, 0, sizeof(*bar));
 122         bar->frame_control = cpu_to_le16(IEEE80211_FTYPE_CTL |
 123                                          IEEE80211_STYPE_BACK_REQ);
 124         memcpy(bar->ra, ra, ETH_ALEN);
 125         memcpy(bar->ta, sdata->vif.addr, ETH_ALEN);
 126         bar_control |= (u16)IEEE80211_BAR_CTRL_ACK_POLICY_NORMAL;
 127         bar_control |= (u16)IEEE80211_BAR_CTRL_CBMTID_COMPRESSED_BA;
 128         bar_control |= (u16)(tid << IEEE80211_BAR_CTRL_TID_INFO_SHIFT);
 129         bar->control = cpu_to_le16(bar_control);
 130         bar->start_seq_num = cpu_to_le16(ssn);
 131
 132         IEEE80211_SKB_CB(skb)->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT;
 133         ieee80211_tx_skb(sdata, skb);
 134 }
 135 EXPORT_SYMBOL(ieee80211_send_bar);
 136
 137 void ieee80211_assign_tid_tx(struct sta_info *sta, int tid,
 138                              struct tid_ampdu_tx *tid_tx)
 139 {
 140         lockdep_assert_held(&sta->ampdu_mlme.mtx);
 141         lockdep_assert_held(&sta->lock);
 142         rcu_assign_pointer(sta->ampdu_mlme.tid_tx[tid], tid_tx);
 143 }
 144
 145 int ___ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
 146                                     enum ieee80211_back_parties initiator,
 147                                     bool tx)
 148 {
 149         struct ieee80211_local *local = sta->local;
 150         struct tid_ampdu_tx *tid_tx;
 151         int ret;
 152
 153         lockdep_assert_held(&sta->ampdu_mlme.mtx);
 154
 155         spin_lock_bh(&sta->lock);
 156
 157         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 158         if (!tid_tx) {
 159                 spin_unlock_bh(&sta->lock);
 160                 return -ENOENT;
 161         }
 162
 163         /* if we're already stopping ignore any new requests to stop */
 164         if (test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
 165                 spin_unlock_bh(&sta->lock);
 166                 return -EALREADY;
 167         }
 168
 169         if (test_bit(HT_AGG_STATE_WANT_START, &tid_tx->state)) {
 170                 /* not even started yet! */
 171                 ieee80211_assign_tid_tx(sta, tid, NULL);
 172                 spin_unlock_bh(&sta->lock);
 173                 kfree_rcu(tid_tx, rcu_head);
 174                 return 0;
 175         }
 176
 177         set_bit(HT_AGG_STATE_STOPPING, &tid_tx->state);
 178
 179         spin_unlock_bh(&sta->lock);
 180
 181 #ifdef CONFIG_MAC80211_HT_DEBUG
 182         printk(KERN_DEBUG "Tx BA session stop requested for %pM tid %u\n",
 183                sta->sta.addr, tid);
 184 #endif /* CONFIG_MAC80211_HT_DEBUG */
 185
 186         del_timer_sync(&tid_tx->addba_resp_timer);
 187
 188         /*
 189          * After this packets are no longer handed right through
 190          * to the driver but are put onto tid_tx->pending instead,
 191          * with locking to ensure proper access.
 192          */
 193         clear_bit(HT_AGG_STATE_OPERATIONAL, &tid_tx->state);
 194
 195         tid_tx->stop_initiator = initiator;
 196         tid_tx->tx_stop = tx;
 197
 198         ret = drv_ampdu_action(local, sta->sdata,
 199                                IEEE80211_AMPDU_TX_STOP,
 200                                &sta->sta, tid, NULL, 0);
 201
 202         /* HW shall not deny going back to legacy */
 203         if (WARN_ON(ret)) {
 204                 /*
 205                  * We may have pending packets get stuck in this case...
 206                  * Not bothering with a workaround for now.
 207                  */
 208         }
 209
 210         return ret;
 211 }
 212
 213 /*
 214  * After sending add Block Ack request we activated a timer until
 215  * add Block Ack response will arrive from the recipient.
 216  * If this timer expires sta_addba_resp_timer_expired will be executed.
 217  */
 218 static void sta_addba_resp_timer_expired(unsigned long data)
 219 {
 220         /* not an elegant detour, but there is no choice as the timer passes
 221          * only one argument, and both sta_info and TID are needed, so init
 222          * flow in sta_info_create gives the TID as data, while the timer_to_id
 223          * array gives the sta through container_of */
 224         u16 tid = *(u8 *)data;
 225         struct sta_info *sta = container_of((void *)data,
 226                 struct sta_info, timer_to_tid[tid]);
 227         struct tid_ampdu_tx *tid_tx;
 228
 229         /* check if the TID waits for addBA response */
 230         rcu_read_lock();
 231         tid_tx = rcu_dereference(sta->ampdu_mlme.tid_tx[tid]);
 232         if (!tid_tx ||
 233             test_bit(HT_AGG_STATE_RESPONSE_RECEIVED, &tid_tx->state)) {
 234                 rcu_read_unlock();
 235 #ifdef CONFIG_MAC80211_HT_DEBUG
 236                 printk(KERN_DEBUG "timer expired on tid %d but we are not "
 237                                 "(or no longer) expecting addBA response there\n",
 238                         tid);
 239 #endif
 240                 return;
 241         }
 242
 243 #ifdef CONFIG_MAC80211_HT_DEBUG
 244         printk(KERN_DEBUG "addBA response timer expired on tid %d\n", tid);
 245 #endif
 246
 247         ieee80211_stop_tx_ba_session(&sta->sta, tid);
 248         rcu_read_unlock();
 249 }
 250
 251 static inline int ieee80211_ac_from_tid(int tid)
 252 {
 253         return ieee802_1d_to_ac[tid & 7];
 254 }
 255
 256 /*
 257  * When multiple aggregation sessions on multiple stations
 258  * are being created/destroyed simultaneously, we need to
 259  * refcount the global queue stop caused by that in order
 260  * to not get into a situation where one of the aggregation
 261  * setup or teardown re-enables queues before the other is
 262  * ready to handle that.
 263  *
 264  * These two functions take care of this issue by keeping
 265  * a global "agg_queue_stop" refcount.
 266  */
 267 static void __acquires(agg_queue)
 268 ieee80211_stop_queue_agg(struct ieee80211_local *local, int tid)
 269 {
 270         int queue = ieee80211_ac_from_tid(tid);
 271
 272         if (atomic_inc_return(&local->agg_queue_stop[queue]) == 1)
 273                 ieee80211_stop_queue_by_reason(
 274                         &local->hw, queue,
 275                         IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
 276         __acquire(agg_queue);
 277 }
 278
 279 static void __releases(agg_queue)
 280 ieee80211_wake_queue_agg(struct ieee80211_local *local, int tid)
 281 {
 282         int queue = ieee80211_ac_from_tid(tid);
 283
 284         if (atomic_dec_return(&local->agg_queue_stop[queue]) == 0)
 285                 ieee80211_wake_queue_by_reason(
 286                         &local->hw, queue,
 287                         IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
 288         __release(agg_queue);
 289 }
 290
 291 void ieee80211_tx_ba_session_handle_start(struct sta_info *sta, int tid)
 292 {
 293         struct tid_ampdu_tx *tid_tx;
 294         struct ieee80211_local *local = sta->local;
 295         struct ieee80211_sub_if_data *sdata = sta->sdata;
 296         u16 start_seq_num;
 297         int ret;
 298
 299         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 300
 301         /*
 302          * While we're asking the driver about the aggregation,
 303          * stop the AC queue so that we don't have to worry
 304          * about frames that came in while we were doing that,
 305          * which would require us to put them to the AC pending
 306          * afterwards which just makes the code more complex.
 307          */
 308         ieee80211_stop_queue_agg(local, tid);
 309
 310         clear_bit(HT_AGG_STATE_WANT_START, &tid_tx->state);
 311
 312         /*
 313          * make sure no packets are being processed to get
 314          * valid starting sequence number
 315          */
 316         synchronize_net();
 317
 318         start_seq_num = sta->tid_seq[tid] >> 4;
 319
 320         ret = drv_ampdu_action(local, sdata, IEEE80211_AMPDU_TX_START,
 321                                &sta->sta, tid, &start_seq_num, 0);
 322         if (ret) {
 323 #ifdef CONFIG_MAC80211_HT_DEBUG
 324                 printk(KERN_DEBUG "BA request denied - HW unavailable for"
 325                                         " tid %d\n", tid);
 326 #endif
 327                 spin_lock_bh(&sta->lock);
 328                 ieee80211_assign_tid_tx(sta, tid, NULL);
 329                 spin_unlock_bh(&sta->lock);
 330
 331                 ieee80211_wake_queue_agg(local, tid);
 332                 kfree_rcu(tid_tx, rcu_head);
 333                 return;
 334         }
 335
 336         /* we can take packets again now */
 337         ieee80211_wake_queue_agg(local, tid);
 338
 339         /* activate the timer for the recipient's addBA response */
 340         mod_timer(&tid_tx->addba_resp_timer, jiffies + ADDBA_RESP_INTERVAL);
 341 #ifdef CONFIG_MAC80211_HT_DEBUG
 342         printk(KERN_DEBUG "activated addBA response timer on tid %d\n", tid);
 343 #endif
 344
 345         spin_lock_bh(&sta->lock);
 346         sta->ampdu_mlme.addba_req_num[tid]++;
 347         spin_unlock_bh(&sta->lock);
 348
 349         /* send AddBA request */
 350         ieee80211_send_addba_request(sdata, sta->sta.addr, tid,
 351                                      tid_tx->dialog_token, start_seq_num,
 352                                      local->hw.max_tx_aggregation_subframes,
 353                                      tid_tx->timeout);
 354 }
 355
 356 int ieee80211_start_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid,
 357                                   u16 timeout)
 358 {
 359         struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
 360         struct ieee80211_sub_if_data *sdata = sta->sdata;
 361         struct ieee80211_local *local = sdata->local;
 362         struct tid_ampdu_tx *tid_tx;
 363         int ret = 0;
 364
 365         trace_api_start_tx_ba_session(pubsta, tid);
 366
 367         if (WARN_ON(!local->ops->ampdu_action))
 368                 return -EINVAL;
 369
 370         if ((tid >= STA_TID_NUM) ||
 371             !(local->hw.flags & IEEE80211_HW_AMPDU_AGGREGATION) ||
 372             (local->hw.flags & IEEE80211_HW_TX_AMPDU_SETUP_IN_HW))
 373                 return -EINVAL;
 374
 375 #ifdef CONFIG_MAC80211_HT_DEBUG
 376         printk(KERN_DEBUG "Open BA session requested for %pM tid %u\n",
 377                pubsta->addr, tid);
 378 #endif /* CONFIG_MAC80211_HT_DEBUG */
 379
 380         /*
 381          * The aggregation code is not prepared to handle
 382          * anything but STA/AP due to the BSSID handling.
 383          * IBSS could work in the code but isn't supported
 384          * by drivers or the standard.
 385          */
 386         if (sdata->vif.type != NL80211_IFTYPE_STATION &&
 387             sdata->vif.type != NL80211_IFTYPE_AP_VLAN &&
 388             sdata->vif.type != NL80211_IFTYPE_AP)
 389                 return -EINVAL;
 390
 391         if (test_sta_flag(sta, WLAN_STA_BLOCK_BA)) {
 392 #ifdef CONFIG_MAC80211_HT_DEBUG
 393                 printk(KERN_DEBUG "BA sessions blocked. "
 394                        "Denying BA session request\n");
 395 #endif
 396                 return -EINVAL;
 397         }
 398
 399         spin_lock_bh(&sta->lock);
 400
 401         /* we have tried too many times, receiver does not want A-MPDU */
 402         if (sta->ampdu_mlme.addba_req_num[tid] > HT_AGG_MAX_RETRIES) {
 403                 ret = -EBUSY;
 404                 goto err_unlock_sta;
 405         }
 406
 407         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 408         /* check if the TID is not in aggregation flow already */
 409         if (tid_tx || sta->ampdu_mlme.tid_start_tx[tid]) {
 410 #ifdef CONFIG_MAC80211_HT_DEBUG
 411                 printk(KERN_DEBUG "BA request denied - session is not "
 412                                  "idle on tid %u\n", tid);
 413 #endif /* CONFIG_MAC80211_HT_DEBUG */
 414                 ret = -EAGAIN;
 415                 goto err_unlock_sta;
 416         }
 417
 418         /* prepare A-MPDU MLME for Tx aggregation */
 419         tid_tx = kzalloc(sizeof(struct tid_ampdu_tx), GFP_ATOMIC);
 420         if (!tid_tx) {
 421                 ret = -ENOMEM;
 422                 goto err_unlock_sta;
 423         }
 424
 425         skb_queue_head_init(&tid_tx->pending);
 426         __set_bit(HT_AGG_STATE_WANT_START, &tid_tx->state);
 427
 428         tid_tx->timeout = timeout;
 429
 430         /* Tx timer */
 431         tid_tx->addba_resp_timer.function = sta_addba_resp_timer_expired;
 432         tid_tx->addba_resp_timer.data = (unsigned long)&sta->timer_to_tid[tid];
 433         init_timer(&tid_tx->addba_resp_timer);
 434
 435         /* assign a dialog token */
 436         sta->ampdu_mlme.dialog_token_allocator++;
 437         tid_tx->dialog_token = sta->ampdu_mlme.dialog_token_allocator;
 438
 439         /*
 440          * Finally, assign it to the start array; the work item will
 441          * collect it and move it to the normal array.
 442          */
 443         sta->ampdu_mlme.tid_start_tx[tid] = tid_tx;
 444
 445         ieee80211_queue_work(&local->hw, &sta->ampdu_mlme.work);
 446
 447         /* this flow continues off the work */
 448  err_unlock_sta:
 449         spin_unlock_bh(&sta->lock);
 450         return ret;
 451 }
 452 EXPORT_SYMBOL(ieee80211_start_tx_ba_session);
 453
 454 /*
 455  * splice packets from the STA's pending to the local pending,
 456  * requires a call to ieee80211_agg_splice_finish later
 457  */
 458 static void __acquires(agg_queue)
 459 ieee80211_agg_splice_packets(struct ieee80211_local *local,
 460                              struct tid_ampdu_tx *tid_tx, u16 tid)
 461 {
 462         int queue = ieee80211_ac_from_tid(tid);
 463         unsigned long flags;
 464
 465         ieee80211_stop_queue_agg(local, tid);
 466
 467         if (WARN(!tid_tx, "TID %d gone but expected when splicing aggregates"
 468                           " from the pending queue\n", tid))
 469                 return;
 470
 471         if (!skb_queue_empty(&tid_tx->pending)) {
 472                 spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
 473                 /* copy over remaining packets */
 474                 skb_queue_splice_tail_init(&tid_tx->pending,
 475                                            &local->pending[queue]);
 476                 spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);
 477         }
 478 }
 479
 480 static void __releases(agg_queue)
 481 ieee80211_agg_splice_finish(struct ieee80211_local *local, u16 tid)
 482 {
 483         ieee80211_wake_queue_agg(local, tid);
 484 }
 485
 486 static void ieee80211_agg_tx_operational(struct ieee80211_local *local,
 487                                          struct sta_info *sta, u16 tid)
 488 {
 489         struct tid_ampdu_tx *tid_tx;
 490
 491         lockdep_assert_held(&sta->ampdu_mlme.mtx);
 492
 493         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 494
 495 #ifdef CONFIG_MAC80211_HT_DEBUG
 496         printk(KERN_DEBUG "Aggregation is on for tid %d\n", tid);
 497 #endif
 498
 499         drv_ampdu_action(local, sta->sdata,
 500                          IEEE80211_AMPDU_TX_OPERATIONAL,
 501                          &sta->sta, tid, NULL, tid_tx->buf_size);
 502
 503         /*
 504          * synchronize with TX path, while splicing the TX path
 505          * should block so it won't put more packets onto pending.
 506          */
 507         spin_lock_bh(&sta->lock);
 508
 509         ieee80211_agg_splice_packets(local, tid_tx, tid);
 510         /*
 511          * Now mark as operational. This will be visible
 512          * in the TX path, and lets it go lock-free in
 513          * the common case.
 514          */
 515         set_bit(HT_AGG_STATE_OPERATIONAL, &tid_tx->state);
 516         ieee80211_agg_splice_finish(local, tid);
 517
 518         spin_unlock_bh(&sta->lock);
 519 }
 520
 521 void ieee80211_start_tx_ba_cb(struct ieee80211_vif *vif, u8 *ra, u16 tid)
 522 {
 523         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 524         struct ieee80211_local *local = sdata->local;
 525         struct sta_info *sta;
 526         struct tid_ampdu_tx *tid_tx;
 527
 528         trace_api_start_tx_ba_cb(sdata, ra, tid);
 529
 530         if (tid >= STA_TID_NUM) {
 531 #ifdef CONFIG_MAC80211_HT_DEBUG
 532                 printk(KERN_DEBUG "Bad TID value: tid = %d (>= %d)\n",
 533                                 tid, STA_TID_NUM);
 534 #endif
 535                 return;
 536         }
 537
 538         mutex_lock(&local->sta_mtx);
 539         sta = sta_info_get(sdata, ra);
 540         if (!sta) {
 541                 mutex_unlock(&local->sta_mtx);
 542 #ifdef CONFIG_MAC80211_HT_DEBUG
 543                 printk(KERN_DEBUG "Could not find station: %pM\n", ra);
 544 #endif
 545                 return;
 546         }
 547
 548         mutex_lock(&sta->ampdu_mlme.mtx);
 549         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 550
 551         if (WARN_ON(!tid_tx)) {
 552 #ifdef CONFIG_MAC80211_HT_DEBUG
 553                 printk(KERN_DEBUG "addBA was not requested!\n");
 554 #endif
 555                 goto unlock;
 556         }
 557
 558         if (WARN_ON(test_and_set_bit(HT_AGG_STATE_DRV_READY, &tid_tx->state)))
 559                 goto unlock;
 560
 561         if (test_bit(HT_AGG_STATE_RESPONSE_RECEIVED, &tid_tx->state))
 562                 ieee80211_agg_tx_operational(local, sta, tid);
 563
 564  unlock:
 565         mutex_unlock(&sta->ampdu_mlme.mtx);
 566         mutex_unlock(&local->sta_mtx);
 567 }
 568
 569 void ieee80211_start_tx_ba_cb_irqsafe(struct ieee80211_vif *vif,
 570                                       const u8 *ra, u16 tid)
 571 {
 572         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 573         struct ieee80211_local *local = sdata->local;
 574         struct ieee80211_ra_tid *ra_tid;
 575         struct sk_buff *skb = dev_alloc_skb(0);
 576
 577         if (unlikely(!skb))
 578                 return;
 579
 580         ra_tid = (struct ieee80211_ra_tid *) &skb->cb;
 581         memcpy(&ra_tid->ra, ra, ETH_ALEN);
 582         ra_tid->tid = tid;
 583
 584         skb->pkt_type = IEEE80211_SDATA_QUEUE_AGG_START;
 585         skb_queue_tail(&sdata->skb_queue, skb);
 586         ieee80211_queue_work(&local->hw, &sdata->work);
 587 }
 588 EXPORT_SYMBOL(ieee80211_start_tx_ba_cb_irqsafe);
 589
 590 int __ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
 591                                    enum ieee80211_back_parties initiator,
 592                                    bool tx)
 593 {
 594         int ret;
 595
 596         mutex_lock(&sta->ampdu_mlme.mtx);
 597
 598         ret = ___ieee80211_stop_tx_ba_session(sta, tid, initiator, tx);
 599
 600         mutex_unlock(&sta->ampdu_mlme.mtx);
 601
 602         return ret;
 603 }
 604
 605 int ieee80211_stop_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid)
 606 {
 607         struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
 608         struct ieee80211_sub_if_data *sdata = sta->sdata;
 609         struct ieee80211_local *local = sdata->local;
 610         struct tid_ampdu_tx *tid_tx;
 611         int ret = 0;
 612
 613         trace_api_stop_tx_ba_session(pubsta, tid);
 614
 615         if (!local->ops->ampdu_action)
 616                 return -EINVAL;
 617
 618         if (tid >= STA_TID_NUM)
 619                 return -EINVAL;
 620
 621         spin_lock_bh(&sta->lock);
 622         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 623
 624         if (!tid_tx) {
 625                 ret = -ENOENT;
 626                 goto unlock;
 627         }
 628
 629         if (test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
 630                 /* already in progress stopping it */
 631                 ret = 0;
 632                 goto unlock;
 633         }
 634
 635         set_bit(HT_AGG_STATE_WANT_STOP, &tid_tx->state);
 636         ieee80211_queue_work(&local->hw, &sta->ampdu_mlme.work);
 637
 638  unlock:
 639         spin_unlock_bh(&sta->lock);
 640         return ret;
 641 }
 642 EXPORT_SYMBOL(ieee80211_stop_tx_ba_session);
 643
 644 void ieee80211_stop_tx_ba_cb(struct ieee80211_vif *vif, u8 *ra, u8 tid)
 645 {
 646         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 647         struct ieee80211_local *local = sdata->local;
 648         struct sta_info *sta;
 649         struct tid_ampdu_tx *tid_tx;
 650
 651         trace_api_stop_tx_ba_cb(sdata, ra, tid);
 652
 653         if (tid >= STA_TID_NUM) {
 654 #ifdef CONFIG_MAC80211_HT_DEBUG
 655                 printk(KERN_DEBUG "Bad TID value: tid = %d (>= %d)\n",
 656                                 tid, STA_TID_NUM);
 657 #endif
 658                 return;
 659         }
 660
 661 #ifdef CONFIG_MAC80211_HT_DEBUG
 662         printk(KERN_DEBUG "Stopping Tx BA session for %pM tid %d\n",
 663                ra, tid);
 664 #endif /* CONFIG_MAC80211_HT_DEBUG */
 665
 666         mutex_lock(&local->sta_mtx);
 667
 668         sta = sta_info_get(sdata, ra);
 669         if (!sta) {
 670 #ifdef CONFIG_MAC80211_HT_DEBUG
 671                 printk(KERN_DEBUG "Could not find station: %pM\n", ra);
 672 #endif
 673                 goto unlock;
 674         }
 675
 676         mutex_lock(&sta->ampdu_mlme.mtx);
 677         spin_lock_bh(&sta->lock);
 678         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 679
 680         if (!tid_tx || !test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
 681 #ifdef CONFIG_MAC80211_HT_DEBUG
 682                 printk(KERN_DEBUG "unexpected callback to A-MPDU stop\n");
 683 #endif
 684                 goto unlock_sta;
 685         }
 686
 687         if (tid_tx->stop_initiator == WLAN_BACK_INITIATOR && tid_tx->tx_stop)
 688                 ieee80211_send_delba(sta->sdata, ra, tid,
 689                         WLAN_BACK_INITIATOR, WLAN_REASON_QSTA_NOT_USE);
 690
 691         /*
 692          * When we get here, the TX path will not be lockless any more wrt.
 693          * aggregation, since the OPERATIONAL bit has long been cleared.
 694          * Thus it will block on getting the lock, if it occurs. So if we
 695          * stop the queue now, we will not get any more packets, and any
 696          * that might be being processed will wait for us here, thereby
 697          * guaranteeing that no packets go to the tid_tx pending queue any
 698          * more.
 699          */
 700
 701         ieee80211_agg_splice_packets(local, tid_tx, tid);
 702
 703         /* future packets must not find the tid_tx struct any more */
 704         ieee80211_assign_tid_tx(sta, tid, NULL);
 705
 706         ieee80211_agg_splice_finish(local, tid);
 707
 708         kfree_rcu(tid_tx, rcu_head);
 709
 710  unlock_sta:
 711         spin_unlock_bh(&sta->lock);
 712         mutex_unlock(&sta->ampdu_mlme.mtx);
 713  unlock:
 714         mutex_unlock(&local->sta_mtx);
 715 }
 716
 717 void ieee80211_stop_tx_ba_cb_irqsafe(struct ieee80211_vif *vif,
 718                                      const u8 *ra, u16 tid)
 719 {
 720         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 721         struct ieee80211_local *local = sdata->local;
 722         struct ieee80211_ra_tid *ra_tid;
 723         struct sk_buff *skb = dev_alloc_skb(0);
 724
 725         if (unlikely(!skb))
 726                 return;
 727
 728         ra_tid = (struct ieee80211_ra_tid *) &skb->cb;
 729         memcpy(&ra_tid->ra, ra, ETH_ALEN);
 730         ra_tid->tid = tid;
 731
 732         skb->pkt_type = IEEE80211_SDATA_QUEUE_AGG_STOP;
 733         skb_queue_tail(&sdata->skb_queue, skb);
 734         ieee80211_queue_work(&local->hw, &sdata->work);
 735 }
 736 EXPORT_SYMBOL(ieee80211_stop_tx_ba_cb_irqsafe);
 737
 738
 739 void ieee80211_process_addba_resp(struct ieee80211_local *local,
 740                                   struct sta_info *sta,
 741                                   struct ieee80211_mgmt *mgmt,
 742                                   size_t len)
 743 {
 744         struct tid_ampdu_tx *tid_tx;
 745         u16 capab, tid;
 746         u8 buf_size;
 747
 748         capab = le16_to_cpu(mgmt->u.action.u.addba_resp.capab);
 749         tid = (capab & IEEE80211_ADDBA_PARAM_TID_MASK) >> 2;
 750         buf_size = (capab & IEEE80211_ADDBA_PARAM_BUF_SIZE_MASK) >> 6;
 751
 752         mutex_lock(&sta->ampdu_mlme.mtx);
 753
 754         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 755         if (!tid_tx)
 756                 goto out;
 757
 758         if (mgmt->u.action.u.addba_resp.dialog_token != tid_tx->dialog_token) {
 759 #ifdef CONFIG_MAC80211_HT_DEBUG
 760                 printk(KERN_DEBUG "wrong addBA response token, tid %d\n", tid);
 761 #endif
 762                 goto out;
 763         }
 764
 765         del_timer(&tid_tx->addba_resp_timer);
 766
 767 #ifdef CONFIG_MAC80211_HT_DEBUG
 768         printk(KERN_DEBUG "switched off addBA timer for tid %d\n", tid);
 769 #endif
 770         /*
 771          * IEEE 802.11-2007 7.3.1.14:
 772          * In an ADDBA Response frame, when the Status Code field
 773          * is set to 0, the Buffer Size subfield is set to a value
 774          * of at least 1.
 775          */
 776         if (le16_to_cpu(mgmt->u.action.u.addba_resp.status)
 777                         == WLAN_STATUS_SUCCESS && buf_size) {
 778                 if (test_and_set_bit(HT_AGG_STATE_RESPONSE_RECEIVED,
 779                                      &tid_tx->state)) {
 780                         /* ignore duplicate response */
 781                         goto out;
 782                 }
 783
 784                 tid_tx->buf_size = buf_size;
 785
 786                 if (test_bit(HT_AGG_STATE_DRV_READY, &tid_tx->state))
 787                         ieee80211_agg_tx_operational(local, sta, tid);
 788
 789                 sta->ampdu_mlme.addba_req_num[tid] = 0;
 790         } else {
 791                 ___ieee80211_stop_tx_ba_session(sta, tid, WLAN_BACK_INITIATOR,
 792                                                 true);
 793         }
 794
 795  out:
 796         mutex_unlock(&sta->ampdu_mlme.mtx);
 797 }