net/mac80211/chan.c

   1 /*
   2  * mac80211 - channel management
   3  */
   4
   5 #include <linux/nl80211.h>
   6 #include <linux/export.h>
   7 #include <linux/rtnetlink.h>
   8 #include <net/cfg80211.h>
   9 #include "ieee80211_i.h"
  10 #include "driver-ops.h"
  11
  12 static enum nl80211_chan_width ieee80211_get_sta_bw(struct ieee80211_sta *sta)
  13 {
  14         switch (sta->bandwidth) {
  15         case IEEE80211_STA_RX_BW_20:
  16                 if (sta->ht_cap.ht_supported)
  17                         return NL80211_CHAN_WIDTH_20;
  18                 else
  19                         return NL80211_CHAN_WIDTH_20_NOHT;
  20         case IEEE80211_STA_RX_BW_40:
  21                 return NL80211_CHAN_WIDTH_40;
  22         case IEEE80211_STA_RX_BW_80:
  23                 return NL80211_CHAN_WIDTH_80;
  24         case IEEE80211_STA_RX_BW_160:
  25                 /*
  26                  * This applied for both 160 and 80+80. since we use
  27                  * the returned value to consider degradation of
  28                  * ctx->conf.min_def, we have to make sure to take
  29                  * the bigger one (NL80211_CHAN_WIDTH_160).
  30                  * Otherwise we might try degrading even when not
  31                  * needed, as the max required sta_bw returned (80+80)
  32                  * might be smaller than the configured bw (160).
  33                  */
  34                 return NL80211_CHAN_WIDTH_160;
  35         default:
  36                 WARN_ON(1);
  37                 return NL80211_CHAN_WIDTH_20;
  38         }
  39 }
  40
  41 static enum nl80211_chan_width
  42 ieee80211_get_max_required_bw(struct ieee80211_sub_if_data *sdata)
  43 {
  44         enum nl80211_chan_width max_bw = NL80211_CHAN_WIDTH_20_NOHT;
  45         struct sta_info *sta;
  46
  47         rcu_read_lock();
  48         list_for_each_entry_rcu(sta, &sdata->local->sta_list, list) {
  49                 if (sdata != sta->sdata &&
  50                     !(sta->sdata->bss && sta->sdata->bss == sdata->bss))
  51                         continue;
  52
  53                 if (!sta->uploaded)
  54                         continue;
  55
  56                 max_bw = max(max_bw, ieee80211_get_sta_bw(&sta->sta));
  57         }
  58         rcu_read_unlock();
  59
  60         return max_bw;
  61 }
  62
  63 static enum nl80211_chan_width
  64 ieee80211_get_chanctx_max_required_bw(struct ieee80211_local *local,
  65                                       struct ieee80211_chanctx_conf *conf)
  66 {
  67         struct ieee80211_sub_if_data *sdata;
  68         enum nl80211_chan_width max_bw = NL80211_CHAN_WIDTH_20_NOHT;
  69
  70         rcu_read_lock();
  71         list_for_each_entry_rcu(sdata, &local->interfaces, list) {
  72                 struct ieee80211_vif *vif = &sdata->vif;
  73                 enum nl80211_chan_width width = NL80211_CHAN_WIDTH_20_NOHT;
  74
  75                 if (!ieee80211_sdata_running(sdata))
  76                         continue;
  77
  78                 if (rcu_access_pointer(sdata->vif.chanctx_conf) != conf)
  79                         continue;
  80
  81                 switch (vif->type) {
  82                 case NL80211_IFTYPE_AP:
  83                 case NL80211_IFTYPE_AP_VLAN:
  84                         width = ieee80211_get_max_required_bw(sdata);
  85                         break;
  86                 case NL80211_IFTYPE_P2P_DEVICE:
  87                         continue;
  88                 case NL80211_IFTYPE_STATION:
  89                 case NL80211_IFTYPE_ADHOC:
  90                 case NL80211_IFTYPE_WDS:
  91                 case NL80211_IFTYPE_MESH_POINT:
  92                         width = vif->bss_conf.chandef.width;
  93                         break;
  94                 case NL80211_IFTYPE_UNSPECIFIED:
  95                 case NUM_NL80211_IFTYPES:
  96                 case NL80211_IFTYPE_MONITOR:
  97                 case NL80211_IFTYPE_P2P_CLIENT:
  98                 case NL80211_IFTYPE_P2P_GO:
  99                         WARN_ON_ONCE(1);
 100                 }
 101                 max_bw = max(max_bw, width);
 102         }
 103
 104         /* use the configured bandwidth in case of monitor interface */
 105         sdata = rcu_dereference(local->monitor_sdata);
 106         if (sdata && rcu_access_pointer(sdata->vif.chanctx_conf) == conf)
 107                 max_bw = max(max_bw, conf->def.width);
 108
 109         rcu_read_unlock();
 110
 111         return max_bw;
 112 }
 113
 114 /*
 115  * recalc the min required chan width of the channel context, which is
 116  * the max of min required widths of all the interfaces bound to this
 117  * channel context.
 118  */
 119 void ieee80211_recalc_chanctx_min_def(struct ieee80211_local *local,
 120                                       struct ieee80211_chanctx *ctx)
 121 {
 122         enum nl80211_chan_width max_bw;
 123         struct cfg80211_chan_def min_def;
 124
 125         lockdep_assert_held(&local->chanctx_mtx);
 126
 127         /* don't optimize 5MHz, 10MHz, and radar_enabled confs */
 128         if (ctx->conf.def.width == NL80211_CHAN_WIDTH_5 ||
 129             ctx->conf.def.width == NL80211_CHAN_WIDTH_10 ||
 130             ctx->conf.radar_enabled) {
 131                 ctx->conf.min_def = ctx->conf.def;
 132                 return;
 133         }
 134
 135         max_bw = ieee80211_get_chanctx_max_required_bw(local, &ctx->conf);
 136
 137         /* downgrade chandef up to max_bw */
 138         min_def = ctx->conf.def;
 139         while (min_def.width > max_bw)
 140                 ieee80211_chandef_downgrade(&min_def);
 141
 142         if (cfg80211_chandef_identical(&ctx->conf.min_def, &min_def))
 143                 return;
 144
 145         ctx->conf.min_def = min_def;
 146         if (!ctx->driver_present)
 147                 return;
 148
 149         drv_change_chanctx(local, ctx, IEEE80211_CHANCTX_CHANGE_MIN_WIDTH);
 150 }
 151
 152 static void ieee80211_change_chanctx(struct ieee80211_local *local,
 153                                      struct ieee80211_chanctx *ctx,
 154                                      const struct cfg80211_chan_def *chandef)
 155 {
 156         if (cfg80211_chandef_identical(&ctx->conf.def, chandef))
 157                 return;
 158
 159         WARN_ON(!cfg80211_chandef_compatible(&ctx->conf.def, chandef));
 160
 161         ctx->conf.def = *chandef;
 162         drv_change_chanctx(local, ctx, IEEE80211_CHANCTX_CHANGE_WIDTH);
 163         ieee80211_recalc_chanctx_min_def(local, ctx);
 164
 165         if (!local->use_chanctx) {
 166                 local->_oper_chandef = *chandef;
 167                 ieee80211_hw_config(local, 0);
 168         }
 169 }
 170
 171 static struct ieee80211_chanctx *
 172 ieee80211_find_chanctx(struct ieee80211_local *local,
 173                        const struct cfg80211_chan_def *chandef,
 174                        enum ieee80211_chanctx_mode mode)
 175 {
 176         struct ieee80211_chanctx *ctx;
 177
 178         lockdep_assert_held(&local->chanctx_mtx);
 179
 180         if (mode == IEEE80211_CHANCTX_EXCLUSIVE)
 181                 return NULL;
 182
 183         list_for_each_entry(ctx, &local->chanctx_list, list) {
 184                 const struct cfg80211_chan_def *compat;
 185
 186                 if (ctx->mode == IEEE80211_CHANCTX_EXCLUSIVE)
 187                         continue;
 188
 189                 compat = cfg80211_chandef_compatible(&ctx->conf.def, chandef);
 190                 if (!compat)
 191                         continue;
 192
 193                 ieee80211_change_chanctx(local, ctx, compat);
 194
 195                 return ctx;
 196         }
 197
 198         return NULL;
 199 }
 200
 201 static bool ieee80211_is_radar_required(struct ieee80211_local *local)
 202 {
 203         struct ieee80211_sub_if_data *sdata;
 204
 205         rcu_read_lock();
 206         list_for_each_entry_rcu(sdata, &local->interfaces, list) {
 207                 if (sdata->radar_required) {
 208                         rcu_read_unlock();
 209                         return true;
 210                 }
 211         }
 212         rcu_read_unlock();
 213
 214         return false;
 215 }
 216
 217 static struct ieee80211_chanctx *
 218 ieee80211_new_chanctx(struct ieee80211_local *local,
 219                       const struct cfg80211_chan_def *chandef,
 220                       enum ieee80211_chanctx_mode mode)
 221 {
 222         struct ieee80211_chanctx *ctx;
 223         u32 changed;
 224         int err;
 225
 226         lockdep_assert_held(&local->chanctx_mtx);
 227
 228         ctx = kzalloc(sizeof(*ctx) + local->hw.chanctx_data_size, GFP_KERNEL);
 229         if (!ctx)
 230                 return ERR_PTR(-ENOMEM);
 231
 232         ctx->conf.def = *chandef;
 233         ctx->conf.rx_chains_static = 1;
 234         ctx->conf.rx_chains_dynamic = 1;
 235         ctx->mode = mode;
 236         ctx->conf.radar_enabled = ieee80211_is_radar_required(local);
 237         ieee80211_recalc_chanctx_min_def(local, ctx);
 238         if (!local->use_chanctx)
 239                 local->hw.conf.radar_enabled = ctx->conf.radar_enabled;
 240
 241         /* we hold the mutex to prevent idle from changing */
 242         lockdep_assert_held(&local->mtx);
 243         /* turn idle off *before* setting channel -- some drivers need that */
 244         changed = ieee80211_idle_off(local);
 245         if (changed)
 246                 ieee80211_hw_config(local, changed);
 247
 248         if (!local->use_chanctx) {
 249                 local->_oper_chandef = *chandef;
 250                 ieee80211_hw_config(local, 0);
 251         } else {
 252                 err = drv_add_chanctx(local, ctx);
 253                 if (err) {
 254                         kfree(ctx);
 255                         ieee80211_recalc_idle(local);
 256                         return ERR_PTR(err);
 257                 }
 258         }
 259
 260         /* and keep the mutex held until the new chanctx is on the list */
 261         list_add_rcu(&ctx->list, &local->chanctx_list);
 262
 263         return ctx;
 264 }
 265
 266 static void ieee80211_free_chanctx(struct ieee80211_local *local,
 267                                    struct ieee80211_chanctx *ctx)
 268 {
 269         bool check_single_channel = false;
 270         lockdep_assert_held(&local->chanctx_mtx);
 271
 272         WARN_ON_ONCE(ctx->refcount != 0);
 273
 274         if (!local->use_chanctx) {
 275                 struct cfg80211_chan_def *chandef = &local->_oper_chandef;
 276                 chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
 277                 chandef->center_freq1 = chandef->chan->center_freq;
 278                 chandef->center_freq2 = 0;
 279
 280                 /* NOTE: Disabling radar is only valid here for
 281                  * single channel context. To be sure, check it ...
 282                  */
 283                 if (local->hw.conf.radar_enabled)
 284                         check_single_channel = true;
 285                 local->hw.conf.radar_enabled = false;
 286
 287                 ieee80211_hw_config(local, 0);
 288         } else {
 289                 drv_remove_chanctx(local, ctx);
 290         }
 291
 292         list_del_rcu(&ctx->list);
 293         kfree_rcu(ctx, rcu_head);
 294
 295         /* throw a warning if this wasn't the only channel context. */
 296         WARN_ON(check_single_channel && !list_empty(&local->chanctx_list));
 297
 298         ieee80211_recalc_idle(local);
 299 }
 300
 301 static int ieee80211_assign_vif_chanctx(struct ieee80211_sub_if_data *sdata,
 302                                         struct ieee80211_chanctx *ctx)
 303 {
 304         struct ieee80211_local *local = sdata->local;
 305         int ret;
 306
 307         lockdep_assert_held(&local->chanctx_mtx);
 308
 309         ret = drv_assign_vif_chanctx(local, sdata, ctx);
 310         if (ret)
 311                 return ret;
 312
 313         rcu_assign_pointer(sdata->vif.chanctx_conf, &ctx->conf);
 314         ctx->refcount++;
 315
 316         ieee80211_recalc_txpower(sdata);
 317         ieee80211_recalc_chanctx_min_def(local, ctx);
 318         sdata->vif.bss_conf.idle = false;
 319
 320         if (sdata->vif.type != NL80211_IFTYPE_P2P_DEVICE &&
 321             sdata->vif.type != NL80211_IFTYPE_MONITOR)
 322                 ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_IDLE);
 323
 324         return 0;
 325 }
 326
 327 static void ieee80211_recalc_chanctx_chantype(struct ieee80211_local *local,
 328                                               struct ieee80211_chanctx *ctx)
 329 {
 330         struct ieee80211_chanctx_conf *conf = &ctx->conf;
 331         struct ieee80211_sub_if_data *sdata;
 332         const struct cfg80211_chan_def *compat = NULL;
 333
 334         lockdep_assert_held(&local->chanctx_mtx);
 335
 336         rcu_read_lock();
 337         list_for_each_entry_rcu(sdata, &local->interfaces, list) {
 338
 339                 if (!ieee80211_sdata_running(sdata))
 340                         continue;
 341                 if (rcu_access_pointer(sdata->vif.chanctx_conf) != conf)
 342                         continue;
 343
 344                 if (!compat)
 345                         compat = &sdata->vif.bss_conf.chandef;
 346
 347                 compat = cfg80211_chandef_compatible(
 348                                 &sdata->vif.bss_conf.chandef, compat);
 349                 if (!compat)
 350                         break;
 351         }
 352         rcu_read_unlock();
 353
 354         if (WARN_ON_ONCE(!compat))
 355                 return;
 356
 357         ieee80211_change_chanctx(local, ctx, compat);
 358 }
 359
 360 static void ieee80211_recalc_radar_chanctx(struct ieee80211_local *local,
 361                                            struct ieee80211_chanctx *chanctx)
 362 {
 363         bool radar_enabled;
 364
 365         lockdep_assert_held(&local->chanctx_mtx);
 366         /* for setting local->radar_detect_enabled */
 367         lockdep_assert_held(&local->mtx);
 368
 369         radar_enabled = ieee80211_is_radar_required(local);
 370
 371         if (radar_enabled == chanctx->conf.radar_enabled)
 372                 return;
 373
 374         chanctx->conf.radar_enabled = radar_enabled;
 375         local->radar_detect_enabled = chanctx->conf.radar_enabled;
 376
 377         if (!local->use_chanctx) {
 378                 local->hw.conf.radar_enabled = chanctx->conf.radar_enabled;
 379                 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 380         }
 381
 382         drv_change_chanctx(local, chanctx, IEEE80211_CHANCTX_CHANGE_RADAR);
 383 }
 384
 385 static void ieee80211_unassign_vif_chanctx(struct ieee80211_sub_if_data *sdata,
 386                                            struct ieee80211_chanctx *ctx)
 387 {
 388         struct ieee80211_local *local = sdata->local;
 389
 390         lockdep_assert_held(&local->chanctx_mtx);
 391
 392         ctx->refcount--;
 393         rcu_assign_pointer(sdata->vif.chanctx_conf, NULL);
 394
 395         sdata->vif.bss_conf.idle = true;
 396
 397         if (sdata->vif.type != NL80211_IFTYPE_P2P_DEVICE &&
 398             sdata->vif.type != NL80211_IFTYPE_MONITOR)
 399                 ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_IDLE);
 400
 401         drv_unassign_vif_chanctx(local, sdata, ctx);
 402
 403         if (ctx->refcount > 0) {
 404                 ieee80211_recalc_chanctx_chantype(sdata->local, ctx);
 405                 ieee80211_recalc_smps_chanctx(local, ctx);
 406                 ieee80211_recalc_radar_chanctx(local, ctx);
 407                 ieee80211_recalc_chanctx_min_def(local, ctx);
 408         }
 409 }
 410
 411 static void __ieee80211_vif_release_channel(struct ieee80211_sub_if_data *sdata)
 412 {
 413         struct ieee80211_local *local = sdata->local;
 414         struct ieee80211_chanctx_conf *conf;
 415         struct ieee80211_chanctx *ctx;
 416
 417         lockdep_assert_held(&local->chanctx_mtx);
 418
 419         conf = rcu_dereference_protected(sdata->vif.chanctx_conf,
 420                                          lockdep_is_held(&local->chanctx_mtx));
 421         if (!conf)
 422                 return;
 423
 424         ctx = container_of(conf, struct ieee80211_chanctx, conf);
 425
 426         ieee80211_unassign_vif_chanctx(sdata, ctx);
 427         if (ctx->refcount == 0)
 428                 ieee80211_free_chanctx(local, ctx);
 429 }
 430
 431 void ieee80211_recalc_smps_chanctx(struct ieee80211_local *local,
 432                                    struct ieee80211_chanctx *chanctx)
 433 {
 434         struct ieee80211_sub_if_data *sdata;
 435         u8 rx_chains_static, rx_chains_dynamic;
 436
 437         lockdep_assert_held(&local->chanctx_mtx);
 438
 439         rx_chains_static = 1;
 440         rx_chains_dynamic = 1;
 441
 442         rcu_read_lock();
 443         list_for_each_entry_rcu(sdata, &local->interfaces, list) {
 444                 u8 needed_static, needed_dynamic;
 445
 446                 if (!ieee80211_sdata_running(sdata))
 447                         continue;
 448
 449                 if (rcu_access_pointer(sdata->vif.chanctx_conf) !=
 450                                                 &chanctx->conf)
 451                         continue;
 452
 453                 switch (sdata->vif.type) {
 454                 case NL80211_IFTYPE_P2P_DEVICE:
 455                         continue;
 456                 case NL80211_IFTYPE_STATION:
 457                         if (!sdata->u.mgd.associated)
 458                                 continue;
 459                         break;
 460                 case NL80211_IFTYPE_AP_VLAN:
 461                         continue;
 462                 case NL80211_IFTYPE_AP:
 463                 case NL80211_IFTYPE_ADHOC:
 464                 case NL80211_IFTYPE_WDS:
 465                 case NL80211_IFTYPE_MESH_POINT:
 466                         break;
 467                 default:
 468                         WARN_ON_ONCE(1);
 469                 }
 470
 471                 switch (sdata->smps_mode) {
 472                 default:
 473                         WARN_ONCE(1, "Invalid SMPS mode %d\n",
 474                                   sdata->smps_mode);
 475                         /* fall through */
 476                 case IEEE80211_SMPS_OFF:
 477                         needed_static = sdata->needed_rx_chains;
 478                         needed_dynamic = sdata->needed_rx_chains;
 479                         break;
 480                 case IEEE80211_SMPS_DYNAMIC:
 481                         needed_static = 1;
 482                         needed_dynamic = sdata->needed_rx_chains;
 483                         break;
 484                 case IEEE80211_SMPS_STATIC:
 485                         needed_static = 1;
 486                         needed_dynamic = 1;
 487                         break;
 488                 }
 489
 490                 rx_chains_static = max(rx_chains_static, needed_static);
 491                 rx_chains_dynamic = max(rx_chains_dynamic, needed_dynamic);
 492         }
 493         rcu_read_unlock();
 494
 495         if (!local->use_chanctx) {
 496                 if (rx_chains_static > 1)
 497                         local->smps_mode = IEEE80211_SMPS_OFF;
 498                 else if (rx_chains_dynamic > 1)
 499                         local->smps_mode = IEEE80211_SMPS_DYNAMIC;
 500                 else
 501                         local->smps_mode = IEEE80211_SMPS_STATIC;
 502                 ieee80211_hw_config(local, 0);
 503         }
 504
 505         if (rx_chains_static == chanctx->conf.rx_chains_static &&
 506             rx_chains_dynamic == chanctx->conf.rx_chains_dynamic)
 507                 return;
 508
 509         chanctx->conf.rx_chains_static = rx_chains_static;
 510         chanctx->conf.rx_chains_dynamic = rx_chains_dynamic;
 511         drv_change_chanctx(local, chanctx, IEEE80211_CHANCTX_CHANGE_RX_CHAINS);
 512 }
 513
 514 int ieee80211_vif_use_channel(struct ieee80211_sub_if_data *sdata,
 515                               const struct cfg80211_chan_def *chandef,
 516                               enum ieee80211_chanctx_mode mode)
 517 {
 518         struct ieee80211_local *local = sdata->local;
 519         struct ieee80211_chanctx *ctx;
 520         int ret;
 521
 522         lockdep_assert_held(&local->mtx);
 523
 524         WARN_ON(sdata->dev && netif_carrier_ok(sdata->dev));
 525
 526         mutex_lock(&local->chanctx_mtx);
 527         __ieee80211_vif_release_channel(sdata);
 528
 529         ctx = ieee80211_find_chanctx(local, chandef, mode);
 530         if (!ctx)
 531                 ctx = ieee80211_new_chanctx(local, chandef, mode);
 532         if (IS_ERR(ctx)) {
 533                 ret = PTR_ERR(ctx);
 534                 goto out;
 535         }
 536
 537         sdata->vif.bss_conf.chandef = *chandef;
 538
 539         ret = ieee80211_assign_vif_chanctx(sdata, ctx);
 540         if (ret) {
 541                 /* if assign fails refcount stays the same */
 542                 if (ctx->refcount == 0)
 543                         ieee80211_free_chanctx(local, ctx);
 544                 goto out;
 545         }
 546
 547         ieee80211_recalc_smps_chanctx(local, ctx);
 548         ieee80211_recalc_radar_chanctx(local, ctx);
 549  out:
 550         mutex_unlock(&local->chanctx_mtx);
 551         return ret;
 552 }
 553
 554 int ieee80211_vif_change_channel(struct ieee80211_sub_if_data *sdata,
 555                                  u32 *changed)
 556 {
 557         struct ieee80211_local *local = sdata->local;
 558         struct ieee80211_chanctx_conf *conf;
 559         struct ieee80211_chanctx *ctx;
 560         const struct cfg80211_chan_def *chandef = &sdata->csa_chandef;
 561         int ret;
 562         u32 chanctx_changed = 0;
 563
 564         lockdep_assert_held(&local->mtx);
 565
 566         /* should never be called if not performing a channel switch. */
 567         if (WARN_ON(!sdata->vif.csa_active))
 568                 return -EINVAL;
 569
 570         if (!cfg80211_chandef_usable(sdata->local->hw.wiphy, chandef,
 571                                      IEEE80211_CHAN_DISABLED))
 572                 return -EINVAL;
 573
 574         mutex_lock(&local->chanctx_mtx);
 575         conf = rcu_dereference_protected(sdata->vif.chanctx_conf,
 576                                          lockdep_is_held(&local->chanctx_mtx));
 577         if (!conf) {
 578                 ret = -EINVAL;
 579                 goto out;
 580         }
 581
 582         ctx = container_of(conf, struct ieee80211_chanctx, conf);
 583         if (ctx->refcount != 1) {
 584                 ret = -EINVAL;
 585                 goto out;
 586         }
 587
 588         if (sdata->vif.bss_conf.chandef.width != chandef->width) {
 589                 chanctx_changed = IEEE80211_CHANCTX_CHANGE_WIDTH;
 590                 *changed |= BSS_CHANGED_BANDWIDTH;
 591         }
 592
 593         sdata->vif.bss_conf.chandef = *chandef;
 594         ctx->conf.def = *chandef;
 595
 596         chanctx_changed |= IEEE80211_CHANCTX_CHANGE_CHANNEL;
 597         drv_change_chanctx(local, ctx, chanctx_changed);
 598
 599         ieee80211_recalc_chanctx_chantype(local, ctx);
 600         ieee80211_recalc_smps_chanctx(local, ctx);
 601         ieee80211_recalc_radar_chanctx(local, ctx);
 602         ieee80211_recalc_chanctx_min_def(local, ctx);
 603
 604         ret = 0;
 605  out:
 606         mutex_unlock(&local->chanctx_mtx);
 607         return ret;
 608 }
 609
 610 int ieee80211_vif_change_bandwidth(struct ieee80211_sub_if_data *sdata,
 611                                    const struct cfg80211_chan_def *chandef,
 612                                    u32 *changed)
 613 {
 614         struct ieee80211_local *local = sdata->local;
 615         struct ieee80211_chanctx_conf *conf;
 616         struct ieee80211_chanctx *ctx;
 617         int ret;
 618
 619         if (!cfg80211_chandef_usable(sdata->local->hw.wiphy, chandef,
 620                                      IEEE80211_CHAN_DISABLED))
 621                 return -EINVAL;
 622
 623         mutex_lock(&local->chanctx_mtx);
 624         if (cfg80211_chandef_identical(chandef, &sdata->vif.bss_conf.chandef)) {
 625                 ret = 0;
 626                 goto out;
 627         }
 628
 629         if (chandef->width == NL80211_CHAN_WIDTH_20_NOHT ||
 630             sdata->vif.bss_conf.chandef.width == NL80211_CHAN_WIDTH_20_NOHT) {
 631                 ret = -EINVAL;
 632                 goto out;
 633         }
 634
 635         conf = rcu_dereference_protected(sdata->vif.chanctx_conf,
 636                                          lockdep_is_held(&local->chanctx_mtx));
 637         if (!conf) {
 638                 ret = -EINVAL;
 639                 goto out;
 640         }
 641
 642         ctx = container_of(conf, struct ieee80211_chanctx, conf);
 643         if (!cfg80211_chandef_compatible(&conf->def, chandef)) {
 644                 ret = -EINVAL;
 645                 goto out;
 646         }
 647
 648         sdata->vif.bss_conf.chandef = *chandef;
 649
 650         ieee80211_recalc_chanctx_chantype(local, ctx);
 651
 652         *changed |= BSS_CHANGED_BANDWIDTH;
 653         ret = 0;
 654  out:
 655         mutex_unlock(&local->chanctx_mtx);
 656         return ret;
 657 }
 658
 659 void ieee80211_vif_release_channel(struct ieee80211_sub_if_data *sdata)
 660 {
 661         WARN_ON(sdata->dev && netif_carrier_ok(sdata->dev));
 662
 663         lockdep_assert_held(&sdata->local->mtx);
 664
 665         mutex_lock(&sdata->local->chanctx_mtx);
 666         __ieee80211_vif_release_channel(sdata);
 667         mutex_unlock(&sdata->local->chanctx_mtx);
 668 }
 669
 670 void ieee80211_vif_vlan_copy_chanctx(struct ieee80211_sub_if_data *sdata)
 671 {
 672         struct ieee80211_local *local = sdata->local;
 673         struct ieee80211_sub_if_data *ap;
 674         struct ieee80211_chanctx_conf *conf;
 675
 676         if (WARN_ON(sdata->vif.type != NL80211_IFTYPE_AP_VLAN || !sdata->bss))
 677                 return;
 678
 679         ap = container_of(sdata->bss, struct ieee80211_sub_if_data, u.ap);
 680
 681         mutex_lock(&local->chanctx_mtx);
 682
 683         conf = rcu_dereference_protected(ap->vif.chanctx_conf,
 684                                          lockdep_is_held(&local->chanctx_mtx));
 685         rcu_assign_pointer(sdata->vif.chanctx_conf, conf);
 686         mutex_unlock(&local->chanctx_mtx);
 687 }
 688
 689 void ieee80211_vif_copy_chanctx_to_vlans(struct ieee80211_sub_if_data *sdata,
 690                                          bool clear)
 691 {
 692         struct ieee80211_local *local = sdata->local;
 693         struct ieee80211_sub_if_data *vlan;
 694         struct ieee80211_chanctx_conf *conf;
 695
 696         ASSERT_RTNL();
 697
 698         if (WARN_ON(sdata->vif.type != NL80211_IFTYPE_AP))
 699                 return;
 700
 701         mutex_lock(&local->chanctx_mtx);
 702
 703         /*
 704          * Check that conf exists, even when clearing this function
 705          * must be called with the AP's channel context still there
 706          * as it would otherwise cause VLANs to have an invalid
 707          * channel context pointer for a while, possibly pointing
 708          * to a channel context that has already been freed.
 709          */
 710         conf = rcu_dereference_protected(sdata->vif.chanctx_conf,
 711                                 lockdep_is_held(&local->chanctx_mtx));
 712         WARN_ON(!conf);
 713
 714         if (clear)
 715                 conf = NULL;
 716
 717         list_for_each_entry(vlan, &sdata->u.ap.vlans, u.vlan.list)
 718                 rcu_assign_pointer(vlan->vif.chanctx_conf, conf);
 719
 720         mutex_unlock(&local->chanctx_mtx);
 721 }
 722
 723 void ieee80211_iter_chan_contexts_atomic(
 724         struct ieee80211_hw *hw,
 725         void (*iter)(struct ieee80211_hw *hw,
 726                      struct ieee80211_chanctx_conf *chanctx_conf,
 727                      void *data),
 728         void *iter_data)
 729 {
 730         struct ieee80211_local *local = hw_to_local(hw);
 731         struct ieee80211_chanctx *ctx;
 732
 733         rcu_read_lock();
 734         list_for_each_entry_rcu(ctx, &local->chanctx_list, list)
 735                 if (ctx->driver_present)
 736                         iter(hw, &ctx->conf, iter_data);
 737         rcu_read_unlock();
 738 }
 739 EXPORT_SYMBOL_GPL(ieee80211_iter_chan_contexts_atomic);