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 <linux/export.h>
  19 #include <net/mac80211.h>
  20 #include "ieee80211_i.h"
  21 #include "driver-ops.h"
  22 #include "wme.h"
  23
  24 /**
  25  * DOC: TX A-MPDU aggregation
  26  *
  27  * Aggregation on the TX side requires setting the hardware flag
  28  * %IEEE80211_HW_AMPDU_AGGREGATION. The driver will then be handed
  29  * packets with a flag indicating A-MPDU aggregation. The driver
  30  * or device is responsible for actually aggregating the frames,
  31  * as well as deciding how many and which to aggregate.
  32  *
  33  * When TX aggregation is started by some subsystem (usually the rate
  34  * control algorithm would be appropriate) by calling the
  35  * ieee80211_start_tx_ba_session() function, the driver will be
  36  * notified via its @ampdu_action function, with the
  37  * %IEEE80211_AMPDU_TX_START action.
  38  *
  39  * In response to that, the driver is later required to call the
  40  * ieee80211_start_tx_ba_cb_irqsafe() function, which will really
  41  * start the aggregation session after the peer has also responded.
  42  * If the peer responds negatively, the session will be stopped
  43  * again right away. Note that it is possible for the aggregation
  44  * session to be stopped before the driver has indicated that it
  45  * is done setting it up, in which case it must not indicate the
  46  * setup completion.
  47  *
  48  * Also note that, since we also need to wait for a response from
  49  * the peer, the driver is notified of the completion of the
  50  * handshake by the %IEEE80211_AMPDU_TX_OPERATIONAL action to the
  51  * @ampdu_action callback.
  52  *
  53  * Similarly, when the aggregation session is stopped by the peer
  54  * or something calling ieee80211_stop_tx_ba_session(), the driver's
  55  * @ampdu_action function will be called with the action
  56  * %IEEE80211_AMPDU_TX_STOP. In this case, the call must not fail,
  57  * and the driver must later call ieee80211_stop_tx_ba_cb_irqsafe().
  58  */
  59
  60 static void ieee80211_send_addba_request(struct ieee80211_sub_if_data *sdata,
  61                                          const u8 *da, u16 tid,
  62                                          u8 dialog_token, u16 start_seq_num,
  63                                          u16 agg_size, u16 timeout)
  64 {
  65         struct ieee80211_local *local = sdata->local;
  66         struct sk_buff *skb;
  67         struct ieee80211_mgmt *mgmt;
  68         u16 capab;
  69
  70         skb = dev_alloc_skb(sizeof(*mgmt) + local->hw.extra_tx_headroom);
  71
  72         if (!skb)
  73                 return;
  74
  75         skb_reserve(skb, local->hw.extra_tx_headroom);
  76         mgmt = (struct ieee80211_mgmt *) skb_put(skb, 24);
  77         memset(mgmt, 0, 24);
  78         memcpy(mgmt->da, da, ETH_ALEN);
  79         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
  80         if (sdata->vif.type == NL80211_IFTYPE_AP ||
  81             sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
  82                 memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
  83         else if (sdata->vif.type == NL80211_IFTYPE_STATION)
  84                 memcpy(mgmt->bssid, sdata->u.mgd.bssid, ETH_ALEN);
  85
  86         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
  87                                           IEEE80211_STYPE_ACTION);
  88
  89         skb_put(skb, 1 + sizeof(mgmt->u.action.u.addba_req));
  90
  91         mgmt->u.action.category = WLAN_CATEGORY_BACK;
  92         mgmt->u.action.u.addba_req.action_code = WLAN_ACTION_ADDBA_REQ;
  93
  94         mgmt->u.action.u.addba_req.dialog_token = dialog_token;
  95         capab = (u16)(1 << 1);          /* bit 1 aggregation policy */
  96         capab |= (u16)(tid << 2);       /* bit 5:2 TID number */
  97         capab |= (u16)(agg_size << 6);  /* bit 15:6 max size of aggergation */
  98
  99         mgmt->u.action.u.addba_req.capab = cpu_to_le16(capab);
 100
 101         mgmt->u.action.u.addba_req.timeout = cpu_to_le16(timeout);
 102         mgmt->u.action.u.addba_req.start_seq_num =
 103                                         cpu_to_le16(start_seq_num << 4);
 104
 105         ieee80211_tx_skb(sdata, skb);
 106 }
 107
 108 void ieee80211_send_bar(struct ieee80211_vif *vif, u8 *ra, u16 tid, u16 ssn)
 109 {
 110         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 111         struct ieee80211_local *local = sdata->local;
 112         struct sk_buff *skb;
 113         struct ieee80211_bar *bar;
 114         u16 bar_control = 0;
 115
 116         skb = dev_alloc_skb(sizeof(*bar) + local->hw.extra_tx_headroom);
 117         if (!skb)
 118                 return;
 119
 120         skb_reserve(skb, local->hw.extra_tx_headroom);
 121         bar = (struct ieee80211_bar *)skb_put(skb, sizeof(*bar));
 122         memset(bar, 0, sizeof(*bar));
 123         bar->frame_control = cpu_to_le16(IEEE80211_FTYPE_CTL |
 124                                          IEEE80211_STYPE_BACK_REQ);
 125         memcpy(bar->ra, ra, ETH_ALEN);
 126         memcpy(bar->ta, sdata->vif.addr, ETH_ALEN);
 127         bar_control |= (u16)IEEE80211_BAR_CTRL_ACK_POLICY_NORMAL;
 128         bar_control |= (u16)IEEE80211_BAR_CTRL_CBMTID_COMPRESSED_BA;
 129         bar_control |= (u16)(tid << IEEE80211_BAR_CTRL_TID_INFO_SHIFT);
 130         bar->control = cpu_to_le16(bar_control);
 131         bar->start_seq_num = cpu_to_le16(ssn);
 132
 133         IEEE80211_SKB_CB(skb)->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT;
 134         ieee80211_tx_skb(sdata, skb);
 135 }
 136 EXPORT_SYMBOL(ieee80211_send_bar);
 137
 138 void ieee80211_assign_tid_tx(struct sta_info *sta, int tid,
 139                              struct tid_ampdu_tx *tid_tx)
 140 {
 141         lockdep_assert_held(&sta->ampdu_mlme.mtx);
 142         lockdep_assert_held(&sta->lock);
 143         rcu_assign_pointer(sta->ampdu_mlme.tid_tx[tid], tid_tx);
 144 }
 145
 146 int ___ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
 147                                     enum ieee80211_back_parties initiator,
 148                                     bool tx)
 149 {
 150         struct ieee80211_local *local = sta->local;
 151         struct tid_ampdu_tx *tid_tx;
 152         int ret;
 153
 154         lockdep_assert_held(&sta->ampdu_mlme.mtx);
 155
 156         spin_lock_bh(&sta->lock);
 157
 158         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 159         if (!tid_tx) {
 160                 spin_unlock_bh(&sta->lock);
 161                 return -ENOENT;
 162         }
 163
 164         /* if we're already stopping ignore any new requests to stop */
 165         if (test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
 166                 spin_unlock_bh(&sta->lock);
 167                 return -EALREADY;
 168         }
 169
 170         if (test_bit(HT_AGG_STATE_WANT_START, &tid_tx->state)) {
 171                 /* not even started yet! */
 172                 ieee80211_assign_tid_tx(sta, tid, NULL);
 173                 spin_unlock_bh(&sta->lock);
 174                 kfree_rcu(tid_tx, rcu_head);
 175                 return 0;
 176         }
 177
 178         set_bit(HT_AGG_STATE_STOPPING, &tid_tx->state);
 179
 180         spin_unlock_bh(&sta->lock);
 181
 182 #ifdef CONFIG_MAC80211_HT_DEBUG
 183         printk(KERN_DEBUG "Tx BA session stop requested for %pM tid %u\n",
 184                sta->sta.addr, tid);
 185 #endif /* CONFIG_MAC80211_HT_DEBUG */
 186
 187         del_timer_sync(&tid_tx->addba_resp_timer);
 188
 189         /*
 190          * After this packets are no longer handed right through
 191          * to the driver but are put onto tid_tx->pending instead,
 192          * with locking to ensure proper access.
 193          */
 194         clear_bit(HT_AGG_STATE_OPERATIONAL, &tid_tx->state);
 195
 196         /*
 197          * There might be a few packets being processed right now (on
 198          * another CPU) that have already gotten past the aggregation
 199          * check when it was still OPERATIONAL and consequently have
 200          * IEEE80211_TX_CTL_AMPDU set. In that case, this code might
 201          * call into the driver at the same time or even before the
 202          * TX paths calls into it, which could confuse the driver.
 203          *
 204          * Wait for all currently running TX paths to finish before
 205          * telling the driver. New packets will not go through since
 206          * the aggregation session is no longer OPERATIONAL.
 207          */
 208         synchronize_net();
 209
 210         tid_tx->stop_initiator = initiator;
 211         tid_tx->tx_stop = tx;
 212
 213         ret = drv_ampdu_action(local, sta->sdata,
 214                                IEEE80211_AMPDU_TX_STOP,
 215                                &sta->sta, tid, NULL, 0);
 216
 217         /* HW shall not deny going back to legacy */
 218         if (WARN_ON(ret)) {
 219                 /*
 220                  * We may have pending packets get stuck in this case...
 221                  * Not bothering with a workaround for now.
 222                  */
 223         }
 224
 225         return ret;
 226 }
 227
 228 /*
 229  * After sending add Block Ack request we activated a timer until
 230  * add Block Ack response will arrive from the recipient.
 231  * If this timer expires sta_addba_resp_timer_expired will be executed.
 232  */
 233 static void sta_addba_resp_timer_expired(unsigned long data)
 234 {
 235         /* not an elegant detour, but there is no choice as the timer passes
 236          * only one argument, and both sta_info and TID are needed, so init
 237          * flow in sta_info_create gives the TID as data, while the timer_to_id
 238          * array gives the sta through container_of */
 239         u16 tid = *(u8 *)data;
 240         struct sta_info *sta = container_of((void *)data,
 241                 struct sta_info, timer_to_tid[tid]);
 242         struct tid_ampdu_tx *tid_tx;
 243
 244         /* check if the TID waits for addBA response */
 245         rcu_read_lock();
 246         tid_tx = rcu_dereference(sta->ampdu_mlme.tid_tx[tid]);
 247         if (!tid_tx ||
 248             test_bit(HT_AGG_STATE_RESPONSE_RECEIVED, &tid_tx->state)) {
 249                 rcu_read_unlock();
 250 #ifdef CONFIG_MAC80211_HT_DEBUG
 251                 printk(KERN_DEBUG "timer expired on tid %d but we are not "
 252                                 "(or no longer) expecting addBA response there\n",
 253                         tid);
 254 #endif
 255                 return;
 256         }
 257
 258 #ifdef CONFIG_MAC80211_HT_DEBUG
 259         printk(KERN_DEBUG "addBA response timer expired on tid %d\n", tid);
 260 #endif
 261
 262         ieee80211_stop_tx_ba_session(&sta->sta, tid);
 263         rcu_read_unlock();
 264 }
 265
 266 static inline int ieee80211_ac_from_tid(int tid)
 267 {
 268         return ieee802_1d_to_ac[tid & 7];
 269 }
 270
 271 /*
 272  * When multiple aggregation sessions on multiple stations
 273  * are being created/destroyed simultaneously, we need to
 274  * refcount the global queue stop caused by that in order
 275  * to not get into a situation where one of the aggregation
 276  * setup or teardown re-enables queues before the other is
 277  * ready to handle that.
 278  *
 279  * These two functions take care of this issue by keeping
 280  * a global "agg_queue_stop" refcount.
 281  */
 282 static void __acquires(agg_queue)
 283 ieee80211_stop_queue_agg(struct ieee80211_local *local, int tid)
 284 {
 285         int queue = ieee80211_ac_from_tid(tid);
 286
 287         if (atomic_inc_return(&local->agg_queue_stop[queue]) == 1)
 288                 ieee80211_stop_queue_by_reason(
 289                         &local->hw, queue,
 290                         IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
 291         __acquire(agg_queue);
 292 }
 293
 294 static void __releases(agg_queue)
 295 ieee80211_wake_queue_agg(struct ieee80211_local *local, int tid)
 296 {
 297         int queue = ieee80211_ac_from_tid(tid);
 298
 299         if (atomic_dec_return(&local->agg_queue_stop[queue]) == 0)
 300                 ieee80211_wake_queue_by_reason(
 301                         &local->hw, queue,
 302                         IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
 303         __release(agg_queue);
 304 }
 305
 306 /*
 307  * splice packets from the STA's pending to the local pending,
 308  * requires a call to ieee80211_agg_splice_finish later
 309  */
 310 static void __acquires(agg_queue)
 311 ieee80211_agg_splice_packets(struct ieee80211_local *local,
 312                              struct tid_ampdu_tx *tid_tx, u16 tid)
 313 {
 314         int queue = ieee80211_ac_from_tid(tid);
 315         unsigned long flags;
 316
 317         ieee80211_stop_queue_agg(local, tid);
 318
 319         if (WARN(!tid_tx, "TID %d gone but expected when splicing aggregates"
 320                           " from the pending queue\n", tid))
 321                 return;
 322
 323         if (!skb_queue_empty(&tid_tx->pending)) {
 324                 spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
 325                 /* copy over remaining packets */
 326                 skb_queue_splice_tail_init(&tid_tx->pending,
 327                                            &local->pending[queue]);
 328                 spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);
 329         }
 330 }
 331
 332 static void __releases(agg_queue)
 333 ieee80211_agg_splice_finish(struct ieee80211_local *local, u16 tid)
 334 {
 335         ieee80211_wake_queue_agg(local, tid);
 336 }
 337
 338 void ieee80211_tx_ba_session_handle_start(struct sta_info *sta, int tid)
 339 {
 340         struct tid_ampdu_tx *tid_tx;
 341         struct ieee80211_local *local = sta->local;
 342         struct ieee80211_sub_if_data *sdata = sta->sdata;
 343         u16 start_seq_num;
 344         int ret;
 345
 346         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 347
 348         /*
 349          * Start queuing up packets for this aggregation session.
 350          * We're going to release them once the driver is OK with
 351          * that.
 352          */
 353         clear_bit(HT_AGG_STATE_WANT_START, &tid_tx->state);
 354
 355         /*
 356          * Make sure no packets are being processed. This ensures that
 357          * we have a valid starting sequence number and that in-flight
 358          * packets have been flushed out and no packets for this TID
 359          * will go into the driver during the ampdu_action call.
 360          */
 361         synchronize_net();
 362
 363         start_seq_num = sta->tid_seq[tid] >> 4;
 364
 365         ret = drv_ampdu_action(local, sdata, IEEE80211_AMPDU_TX_START,
 366                                &sta->sta, tid, &start_seq_num, 0);
 367         if (ret) {
 368 #ifdef CONFIG_MAC80211_HT_DEBUG
 369                 printk(KERN_DEBUG "BA request denied - HW unavailable for"
 370                                         " tid %d\n", tid);
 371 #endif
 372                 spin_lock_bh(&sta->lock);
 373                 ieee80211_agg_splice_packets(local, tid_tx, tid);
 374                 ieee80211_assign_tid_tx(sta, tid, NULL);
 375                 ieee80211_agg_splice_finish(local, tid);
 376                 spin_unlock_bh(&sta->lock);
 377
 378                 kfree_rcu(tid_tx, rcu_head);
 379                 return;
 380         }
 381
 382         /* activate the timer for the recipient's addBA response */
 383         mod_timer(&tid_tx->addba_resp_timer, jiffies + ADDBA_RESP_INTERVAL);
 384 #ifdef CONFIG_MAC80211_HT_DEBUG
 385         printk(KERN_DEBUG "activated addBA response timer on tid %d\n", tid);
 386 #endif
 387
 388         spin_lock_bh(&sta->lock);
 389         sta->ampdu_mlme.addba_req_num[tid]++;
 390         spin_unlock_bh(&sta->lock);
 391
 392         /* send AddBA request */
 393         ieee80211_send_addba_request(sdata, sta->sta.addr, tid,
 394                                      tid_tx->dialog_token, start_seq_num,
 395                                      local->hw.max_tx_aggregation_subframes,
 396                                      tid_tx->timeout);
 397 }
 398
 399 int ieee80211_start_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid,
 400                                   u16 timeout)
 401 {
 402         struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
 403         struct ieee80211_sub_if_data *sdata = sta->sdata;
 404         struct ieee80211_local *local = sdata->local;
 405         struct tid_ampdu_tx *tid_tx;
 406         int ret = 0;
 407
 408         trace_api_start_tx_ba_session(pubsta, tid);
 409
 410         if (WARN_ON(!local->ops->ampdu_action))
 411                 return -EINVAL;
 412
 413         if ((tid >= STA_TID_NUM) ||
 414             !(local->hw.flags & IEEE80211_HW_AMPDU_AGGREGATION) ||
 415             (local->hw.flags & IEEE80211_HW_TX_AMPDU_SETUP_IN_HW))
 416                 return -EINVAL;
 417
 418 #ifdef CONFIG_MAC80211_HT_DEBUG
 419         printk(KERN_DEBUG "Open BA session requested for %pM tid %u\n",
 420                pubsta->addr, tid);
 421 #endif /* CONFIG_MAC80211_HT_DEBUG */
 422
 423         /*
 424          * The aggregation code is not prepared to handle
 425          * anything but STA/AP due to the BSSID handling.
 426          * IBSS could work in the code but isn't supported
 427          * by drivers or the standard.
 428          */
 429         if (sdata->vif.type != NL80211_IFTYPE_STATION &&
 430             sdata->vif.type != NL80211_IFTYPE_AP_VLAN &&
 431             sdata->vif.type != NL80211_IFTYPE_AP)
 432                 return -EINVAL;
 433
 434         if (test_sta_flag(sta, WLAN_STA_BLOCK_BA)) {
 435 #ifdef CONFIG_MAC80211_HT_DEBUG
 436                 printk(KERN_DEBUG "BA sessions blocked. "
 437                        "Denying BA session request\n");
 438 #endif
 439                 return -EINVAL;
 440         }
 441
 442         spin_lock_bh(&sta->lock);
 443
 444         /* we have tried too many times, receiver does not want A-MPDU */
 445         if (sta->ampdu_mlme.addba_req_num[tid] > HT_AGG_MAX_RETRIES) {
 446                 ret = -EBUSY;
 447                 goto err_unlock_sta;
 448         }
 449
 450         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 451         /* check if the TID is not in aggregation flow already */
 452         if (tid_tx || sta->ampdu_mlme.tid_start_tx[tid]) {
 453 #ifdef CONFIG_MAC80211_HT_DEBUG
 454                 printk(KERN_DEBUG "BA request denied - session is not "
 455                                  "idle on tid %u\n", tid);
 456 #endif /* CONFIG_MAC80211_HT_DEBUG */
 457                 ret = -EAGAIN;
 458                 goto err_unlock_sta;
 459         }
 460
 461         /* prepare A-MPDU MLME for Tx aggregation */
 462         tid_tx = kzalloc(sizeof(struct tid_ampdu_tx), GFP_ATOMIC);
 463         if (!tid_tx) {
 464                 ret = -ENOMEM;
 465                 goto err_unlock_sta;
 466         }
 467
 468         skb_queue_head_init(&tid_tx->pending);
 469         __set_bit(HT_AGG_STATE_WANT_START, &tid_tx->state);
 470
 471         tid_tx->timeout = timeout;
 472
 473         /* Tx timer */
 474         tid_tx->addba_resp_timer.function = sta_addba_resp_timer_expired;
 475         tid_tx->addba_resp_timer.data = (unsigned long)&sta->timer_to_tid[tid];
 476         init_timer(&tid_tx->addba_resp_timer);
 477
 478         /* assign a dialog token */
 479         sta->ampdu_mlme.dialog_token_allocator++;
 480         tid_tx->dialog_token = sta->ampdu_mlme.dialog_token_allocator;
 481
 482         /*
 483          * Finally, assign it to the start array; the work item will
 484          * collect it and move it to the normal array.
 485          */
 486         sta->ampdu_mlme.tid_start_tx[tid] = tid_tx;
 487
 488         ieee80211_queue_work(&local->hw, &sta->ampdu_mlme.work);
 489
 490         /* this flow continues off the work */
 491  err_unlock_sta:
 492         spin_unlock_bh(&sta->lock);
 493         return ret;
 494 }
 495 EXPORT_SYMBOL(ieee80211_start_tx_ba_session);
 496
 497 static void ieee80211_agg_tx_operational(struct ieee80211_local *local,
 498                                          struct sta_info *sta, u16 tid)
 499 {
 500         struct tid_ampdu_tx *tid_tx;
 501
 502         lockdep_assert_held(&sta->ampdu_mlme.mtx);
 503
 504         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 505
 506 #ifdef CONFIG_MAC80211_HT_DEBUG
 507         printk(KERN_DEBUG "Aggregation is on for tid %d\n", tid);
 508 #endif
 509
 510         drv_ampdu_action(local, sta->sdata,
 511                          IEEE80211_AMPDU_TX_OPERATIONAL,
 512                          &sta->sta, tid, NULL, tid_tx->buf_size);
 513
 514         /*
 515          * synchronize with TX path, while splicing the TX path
 516          * should block so it won't put more packets onto pending.
 517          */
 518         spin_lock_bh(&sta->lock);
 519
 520         ieee80211_agg_splice_packets(local, tid_tx, tid);
 521         /*
 522          * Now mark as operational. This will be visible
 523          * in the TX path, and lets it go lock-free in
 524          * the common case.
 525          */
 526         set_bit(HT_AGG_STATE_OPERATIONAL, &tid_tx->state);
 527         ieee80211_agg_splice_finish(local, tid);
 528
 529         spin_unlock_bh(&sta->lock);
 530 }
 531
 532 void ieee80211_start_tx_ba_cb(struct ieee80211_vif *vif, u8 *ra, u16 tid)
 533 {
 534         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 535         struct ieee80211_local *local = sdata->local;
 536         struct sta_info *sta;
 537         struct tid_ampdu_tx *tid_tx;
 538
 539         trace_api_start_tx_ba_cb(sdata, ra, tid);
 540
 541         if (tid >= STA_TID_NUM) {
 542 #ifdef CONFIG_MAC80211_HT_DEBUG
 543                 printk(KERN_DEBUG "Bad TID value: tid = %d (>= %d)\n",
 544                                 tid, STA_TID_NUM);
 545 #endif
 546                 return;
 547         }
 548
 549         mutex_lock(&local->sta_mtx);
 550         sta = sta_info_get(sdata, ra);
 551         if (!sta) {
 552                 mutex_unlock(&local->sta_mtx);
 553 #ifdef CONFIG_MAC80211_HT_DEBUG
 554                 printk(KERN_DEBUG "Could not find station: %pM\n", ra);
 555 #endif
 556                 return;
 557         }
 558
 559         mutex_lock(&sta->ampdu_mlme.mtx);
 560         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 561
 562         if (WARN_ON(!tid_tx)) {
 563 #ifdef CONFIG_MAC80211_HT_DEBUG
 564                 printk(KERN_DEBUG "addBA was not requested!\n");
 565 #endif
 566                 goto unlock;
 567         }
 568
 569         if (WARN_ON(test_and_set_bit(HT_AGG_STATE_DRV_READY, &tid_tx->state)))
 570                 goto unlock;
 571
 572         if (test_bit(HT_AGG_STATE_RESPONSE_RECEIVED, &tid_tx->state))
 573                 ieee80211_agg_tx_operational(local, sta, tid);
 574
 575  unlock:
 576         mutex_unlock(&sta->ampdu_mlme.mtx);
 577         mutex_unlock(&local->sta_mtx);
 578 }
 579
 580 void ieee80211_start_tx_ba_cb_irqsafe(struct ieee80211_vif *vif,
 581                                       const u8 *ra, u16 tid)
 582 {
 583         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 584         struct ieee80211_local *local = sdata->local;
 585         struct ieee80211_ra_tid *ra_tid;
 586         struct sk_buff *skb = dev_alloc_skb(0);
 587
 588         if (unlikely(!skb))
 589                 return;
 590
 591         ra_tid = (struct ieee80211_ra_tid *) &skb->cb;
 592         memcpy(&ra_tid->ra, ra, ETH_ALEN);
 593         ra_tid->tid = tid;
 594
 595         skb->pkt_type = IEEE80211_SDATA_QUEUE_AGG_START;
 596         skb_queue_tail(&sdata->skb_queue, skb);
 597         ieee80211_queue_work(&local->hw, &sdata->work);
 598 }
 599 EXPORT_SYMBOL(ieee80211_start_tx_ba_cb_irqsafe);
 600
 601 int __ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
 602                                    enum ieee80211_back_parties initiator,
 603                                    bool tx)
 604 {
 605         int ret;
 606
 607         mutex_lock(&sta->ampdu_mlme.mtx);
 608
 609         ret = ___ieee80211_stop_tx_ba_session(sta, tid, initiator, tx);
 610
 611         mutex_unlock(&sta->ampdu_mlme.mtx);
 612
 613         return ret;
 614 }
 615
 616 int ieee80211_stop_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid)
 617 {
 618         struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
 619         struct ieee80211_sub_if_data *sdata = sta->sdata;
 620         struct ieee80211_local *local = sdata->local;
 621         struct tid_ampdu_tx *tid_tx;
 622         int ret = 0;
 623
 624         trace_api_stop_tx_ba_session(pubsta, tid);
 625
 626         if (!local->ops->ampdu_action)
 627                 return -EINVAL;
 628
 629         if (tid >= STA_TID_NUM)
 630                 return -EINVAL;
 631
 632         spin_lock_bh(&sta->lock);
 633         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 634
 635         if (!tid_tx) {
 636                 ret = -ENOENT;
 637                 goto unlock;
 638         }
 639
 640         if (test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
 641                 /* already in progress stopping it */
 642                 ret = 0;
 643                 goto unlock;
 644         }
 645
 646         set_bit(HT_AGG_STATE_WANT_STOP, &tid_tx->state);
 647         ieee80211_queue_work(&local->hw, &sta->ampdu_mlme.work);
 648
 649  unlock:
 650         spin_unlock_bh(&sta->lock);
 651         return ret;
 652 }
 653 EXPORT_SYMBOL(ieee80211_stop_tx_ba_session);
 654
 655 void ieee80211_stop_tx_ba_cb(struct ieee80211_vif *vif, u8 *ra, u8 tid)
 656 {
 657         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 658         struct ieee80211_local *local = sdata->local;
 659         struct sta_info *sta;
 660         struct tid_ampdu_tx *tid_tx;
 661
 662         trace_api_stop_tx_ba_cb(sdata, ra, tid);
 663
 664         if (tid >= STA_TID_NUM) {
 665 #ifdef CONFIG_MAC80211_HT_DEBUG
 666                 printk(KERN_DEBUG "Bad TID value: tid = %d (>= %d)\n",
 667                                 tid, STA_TID_NUM);
 668 #endif
 669                 return;
 670         }
 671
 672 #ifdef CONFIG_MAC80211_HT_DEBUG
 673         printk(KERN_DEBUG "Stopping Tx BA session for %pM tid %d\n",
 674                ra, tid);
 675 #endif /* CONFIG_MAC80211_HT_DEBUG */
 676
 677         mutex_lock(&local->sta_mtx);
 678
 679         sta = sta_info_get(sdata, ra);
 680         if (!sta) {
 681 #ifdef CONFIG_MAC80211_HT_DEBUG
 682                 printk(KERN_DEBUG "Could not find station: %pM\n", ra);
 683 #endif
 684                 goto unlock;
 685         }
 686
 687         mutex_lock(&sta->ampdu_mlme.mtx);
 688         spin_lock_bh(&sta->lock);
 689         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 690
 691         if (!tid_tx || !test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
 692 #ifdef CONFIG_MAC80211_HT_DEBUG
 693                 printk(KERN_DEBUG "unexpected callback to A-MPDU stop\n");
 694 #endif
 695                 goto unlock_sta;
 696         }
 697
 698         if (tid_tx->stop_initiator == WLAN_BACK_INITIATOR && tid_tx->tx_stop)
 699                 ieee80211_send_delba(sta->sdata, ra, tid,
 700                         WLAN_BACK_INITIATOR, WLAN_REASON_QSTA_NOT_USE);
 701
 702         /*
 703          * When we get here, the TX path will not be lockless any more wrt.
 704          * aggregation, since the OPERATIONAL bit has long been cleared.
 705          * Thus it will block on getting the lock, if it occurs. So if we
 706          * stop the queue now, we will not get any more packets, and any
 707          * that might be being processed will wait for us here, thereby
 708          * guaranteeing that no packets go to the tid_tx pending queue any
 709          * more.
 710          */
 711
 712         ieee80211_agg_splice_packets(local, tid_tx, tid);
 713
 714         /* future packets must not find the tid_tx struct any more */
 715         ieee80211_assign_tid_tx(sta, tid, NULL);
 716
 717         ieee80211_agg_splice_finish(local, tid);
 718
 719         kfree_rcu(tid_tx, rcu_head);
 720
 721  unlock_sta:
 722         spin_unlock_bh(&sta->lock);
 723         mutex_unlock(&sta->ampdu_mlme.mtx);
 724  unlock:
 725         mutex_unlock(&local->sta_mtx);
 726 }
 727
 728 void ieee80211_stop_tx_ba_cb_irqsafe(struct ieee80211_vif *vif,
 729                                      const u8 *ra, u16 tid)
 730 {
 731         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 732         struct ieee80211_local *local = sdata->local;
 733         struct ieee80211_ra_tid *ra_tid;
 734         struct sk_buff *skb = dev_alloc_skb(0);
 735
 736         if (unlikely(!skb))
 737                 return;
 738
 739         ra_tid = (struct ieee80211_ra_tid *) &skb->cb;
 740         memcpy(&ra_tid->ra, ra, ETH_ALEN);
 741         ra_tid->tid = tid;
 742
 743         skb->pkt_type = IEEE80211_SDATA_QUEUE_AGG_STOP;
 744         skb_queue_tail(&sdata->skb_queue, skb);
 745         ieee80211_queue_work(&local->hw, &sdata->work);
 746 }
 747 EXPORT_SYMBOL(ieee80211_stop_tx_ba_cb_irqsafe);
 748
 749
 750 void ieee80211_process_addba_resp(struct ieee80211_local *local,
 751                                   struct sta_info *sta,
 752                                   struct ieee80211_mgmt *mgmt,
 753                                   size_t len)
 754 {
 755         struct tid_ampdu_tx *tid_tx;
 756         u16 capab, tid;
 757         u8 buf_size;
 758
 759         capab = le16_to_cpu(mgmt->u.action.u.addba_resp.capab);
 760         tid = (capab & IEEE80211_ADDBA_PARAM_TID_MASK) >> 2;
 761         buf_size = (capab & IEEE80211_ADDBA_PARAM_BUF_SIZE_MASK) >> 6;
 762
 763         mutex_lock(&sta->ampdu_mlme.mtx);
 764
 765         tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 766         if (!tid_tx)
 767                 goto out;
 768
 769         if (mgmt->u.action.u.addba_resp.dialog_token != tid_tx->dialog_token) {
 770 #ifdef CONFIG_MAC80211_HT_DEBUG
 771                 printk(KERN_DEBUG "wrong addBA response token, tid %d\n", tid);
 772 #endif
 773                 goto out;
 774         }
 775
 776         del_timer_sync(&tid_tx->addba_resp_timer);
 777
 778 #ifdef CONFIG_MAC80211_HT_DEBUG
 779         printk(KERN_DEBUG "switched off addBA timer for tid %d\n", tid);
 780 #endif
 781
 782         /*
 783          * addba_resp_timer may have fired before we got here, and
 784          * caused WANT_STOP to be set. If the stop then was already
 785          * processed further, STOPPING might be set.
 786          */
 787         if (test_bit(HT_AGG_STATE_WANT_STOP, &tid_tx->state) ||
 788             test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
 789 #ifdef CONFIG_MAC80211_HT_DEBUG
 790                 printk(KERN_DEBUG
 791                        "got addBA resp for tid %d but we already gave up\n",
 792                        tid);
 793 #endif
 794                 goto out;
 795         }
 796
 797         /*
 798          * IEEE 802.11-2007 7.3.1.14:
 799          * In an ADDBA Response frame, when the Status Code field
 800          * is set to 0, the Buffer Size subfield is set to a value
 801          * of at least 1.
 802          */
 803         if (le16_to_cpu(mgmt->u.action.u.addba_resp.status)
 804                         == WLAN_STATUS_SUCCESS && buf_size) {
 805                 if (test_and_set_bit(HT_AGG_STATE_RESPONSE_RECEIVED,
 806                                      &tid_tx->state)) {
 807                         /* ignore duplicate response */
 808                         goto out;
 809                 }
 810
 811                 tid_tx->buf_size = buf_size;
 812
 813                 if (test_bit(HT_AGG_STATE_DRV_READY, &tid_tx->state))
 814                         ieee80211_agg_tx_operational(local, sta, tid);
 815
 816                 sta->ampdu_mlme.addba_req_num[tid] = 0;
 817         } else {
 818                 ___ieee80211_stop_tx_ba_session(sta, tid, WLAN_BACK_INITIATOR,
 819                                                 true);
 820         }
 821
 822  out:
 823         mutex_unlock(&sta->ampdu_mlme.mtx);
 824 }