xref: /linux/net/mac80211/chan.c (revision c5aec4c76af1a2d89ee2f2d4d5463b2ad2d85de5)
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 	lockdep_assert_held(&local->mtx);
206 
207 	rcu_read_lock();
208 	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
209 		if (sdata->radar_required) {
210 			rcu_read_unlock();
211 			return true;
212 		}
213 	}
214 	rcu_read_unlock();
215 
216 	return false;
217 }
218 
219 static struct ieee80211_chanctx *
220 ieee80211_new_chanctx(struct ieee80211_local *local,
221 		      const struct cfg80211_chan_def *chandef,
222 		      enum ieee80211_chanctx_mode mode)
223 {
224 	struct ieee80211_chanctx *ctx;
225 	u32 changed;
226 	int err;
227 
228 	lockdep_assert_held(&local->chanctx_mtx);
229 
230 	ctx = kzalloc(sizeof(*ctx) + local->hw.chanctx_data_size, GFP_KERNEL);
231 	if (!ctx)
232 		return ERR_PTR(-ENOMEM);
233 
234 	ctx->conf.def = *chandef;
235 	ctx->conf.rx_chains_static = 1;
236 	ctx->conf.rx_chains_dynamic = 1;
237 	ctx->mode = mode;
238 	ctx->conf.radar_enabled = ieee80211_is_radar_required(local);
239 	ieee80211_recalc_chanctx_min_def(local, ctx);
240 	if (!local->use_chanctx)
241 		local->hw.conf.radar_enabled = ctx->conf.radar_enabled;
242 
243 	/* we hold the mutex to prevent idle from changing */
244 	lockdep_assert_held(&local->mtx);
245 	/* turn idle off *before* setting channel -- some drivers need that */
246 	changed = ieee80211_idle_off(local);
247 	if (changed)
248 		ieee80211_hw_config(local, changed);
249 
250 	if (!local->use_chanctx) {
251 		local->_oper_chandef = *chandef;
252 		ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
253 	} else {
254 		err = drv_add_chanctx(local, ctx);
255 		if (err) {
256 			kfree(ctx);
257 			ieee80211_recalc_idle(local);
258 			return ERR_PTR(err);
259 		}
260 	}
261 
262 	/* and keep the mutex held until the new chanctx is on the list */
263 	list_add_rcu(&ctx->list, &local->chanctx_list);
264 
265 	return ctx;
266 }
267 
268 static void ieee80211_free_chanctx(struct ieee80211_local *local,
269 				   struct ieee80211_chanctx *ctx)
270 {
271 	bool check_single_channel = false;
272 	lockdep_assert_held(&local->chanctx_mtx);
273 
274 	WARN_ON_ONCE(ctx->refcount != 0);
275 
276 	if (!local->use_chanctx) {
277 		struct cfg80211_chan_def *chandef = &local->_oper_chandef;
278 		chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
279 		chandef->center_freq1 = chandef->chan->center_freq;
280 		chandef->center_freq2 = 0;
281 
282 		/* NOTE: Disabling radar is only valid here for
283 		 * single channel context. To be sure, check it ...
284 		 */
285 		if (local->hw.conf.radar_enabled)
286 			check_single_channel = true;
287 		local->hw.conf.radar_enabled = false;
288 
289 		ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
290 	} else {
291 		drv_remove_chanctx(local, ctx);
292 	}
293 
294 	list_del_rcu(&ctx->list);
295 	kfree_rcu(ctx, rcu_head);
296 
297 	/* throw a warning if this wasn't the only channel context. */
298 	WARN_ON(check_single_channel && !list_empty(&local->chanctx_list));
299 
300 	ieee80211_recalc_idle(local);
301 }
302 
303 static int ieee80211_assign_vif_chanctx(struct ieee80211_sub_if_data *sdata,
304 					struct ieee80211_chanctx *ctx)
305 {
306 	struct ieee80211_local *local = sdata->local;
307 	int ret;
308 
309 	lockdep_assert_held(&local->chanctx_mtx);
310 
311 	ret = drv_assign_vif_chanctx(local, sdata, ctx);
312 	if (ret)
313 		return ret;
314 
315 	rcu_assign_pointer(sdata->vif.chanctx_conf, &ctx->conf);
316 	ctx->refcount++;
317 
318 	ieee80211_recalc_txpower(sdata);
319 	ieee80211_recalc_chanctx_min_def(local, ctx);
320 	sdata->vif.bss_conf.idle = false;
321 
322 	if (sdata->vif.type != NL80211_IFTYPE_P2P_DEVICE &&
323 	    sdata->vif.type != NL80211_IFTYPE_MONITOR)
324 		ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_IDLE);
325 
326 	return 0;
327 }
328 
329 static void ieee80211_recalc_chanctx_chantype(struct ieee80211_local *local,
330 					      struct ieee80211_chanctx *ctx)
331 {
332 	struct ieee80211_chanctx_conf *conf = &ctx->conf;
333 	struct ieee80211_sub_if_data *sdata;
334 	const struct cfg80211_chan_def *compat = NULL;
335 
336 	lockdep_assert_held(&local->chanctx_mtx);
337 
338 	rcu_read_lock();
339 	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
340 
341 		if (!ieee80211_sdata_running(sdata))
342 			continue;
343 		if (rcu_access_pointer(sdata->vif.chanctx_conf) != conf)
344 			continue;
345 
346 		if (!compat)
347 			compat = &sdata->vif.bss_conf.chandef;
348 
349 		compat = cfg80211_chandef_compatible(
350 				&sdata->vif.bss_conf.chandef, compat);
351 		if (!compat)
352 			break;
353 	}
354 	rcu_read_unlock();
355 
356 	if (WARN_ON_ONCE(!compat))
357 		return;
358 
359 	ieee80211_change_chanctx(local, ctx, compat);
360 }
361 
362 static void ieee80211_recalc_radar_chanctx(struct ieee80211_local *local,
363 					   struct ieee80211_chanctx *chanctx)
364 {
365 	bool radar_enabled;
366 
367 	lockdep_assert_held(&local->chanctx_mtx);
368 	/* for setting local->radar_detect_enabled */
369 	lockdep_assert_held(&local->mtx);
370 
371 	radar_enabled = ieee80211_is_radar_required(local);
372 
373 	if (radar_enabled == chanctx->conf.radar_enabled)
374 		return;
375 
376 	chanctx->conf.radar_enabled = radar_enabled;
377 	local->radar_detect_enabled = chanctx->conf.radar_enabled;
378 
379 	if (!local->use_chanctx) {
380 		local->hw.conf.radar_enabled = chanctx->conf.radar_enabled;
381 		ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
382 	}
383 
384 	drv_change_chanctx(local, chanctx, IEEE80211_CHANCTX_CHANGE_RADAR);
385 }
386 
387 static void ieee80211_unassign_vif_chanctx(struct ieee80211_sub_if_data *sdata,
388 					   struct ieee80211_chanctx *ctx)
389 {
390 	struct ieee80211_local *local = sdata->local;
391 
392 	lockdep_assert_held(&local->chanctx_mtx);
393 
394 	ctx->refcount--;
395 	rcu_assign_pointer(sdata->vif.chanctx_conf, NULL);
396 
397 	sdata->vif.bss_conf.idle = true;
398 
399 	if (sdata->vif.type != NL80211_IFTYPE_P2P_DEVICE &&
400 	    sdata->vif.type != NL80211_IFTYPE_MONITOR)
401 		ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_IDLE);
402 
403 	drv_unassign_vif_chanctx(local, sdata, ctx);
404 
405 	if (ctx->refcount > 0) {
406 		ieee80211_recalc_chanctx_chantype(sdata->local, ctx);
407 		ieee80211_recalc_smps_chanctx(local, ctx);
408 		ieee80211_recalc_radar_chanctx(local, ctx);
409 		ieee80211_recalc_chanctx_min_def(local, ctx);
410 	}
411 }
412 
413 static void __ieee80211_vif_release_channel(struct ieee80211_sub_if_data *sdata)
414 {
415 	struct ieee80211_local *local = sdata->local;
416 	struct ieee80211_chanctx_conf *conf;
417 	struct ieee80211_chanctx *ctx;
418 
419 	lockdep_assert_held(&local->chanctx_mtx);
420 
421 	conf = rcu_dereference_protected(sdata->vif.chanctx_conf,
422 					 lockdep_is_held(&local->chanctx_mtx));
423 	if (!conf)
424 		return;
425 
426 	ctx = container_of(conf, struct ieee80211_chanctx, conf);
427 
428 	ieee80211_unassign_vif_chanctx(sdata, ctx);
429 	if (ctx->refcount == 0)
430 		ieee80211_free_chanctx(local, ctx);
431 }
432 
433 void ieee80211_recalc_smps_chanctx(struct ieee80211_local *local,
434 				   struct ieee80211_chanctx *chanctx)
435 {
436 	struct ieee80211_sub_if_data *sdata;
437 	u8 rx_chains_static, rx_chains_dynamic;
438 
439 	lockdep_assert_held(&local->chanctx_mtx);
440 
441 	rx_chains_static = 1;
442 	rx_chains_dynamic = 1;
443 
444 	rcu_read_lock();
445 	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
446 		u8 needed_static, needed_dynamic;
447 
448 		if (!ieee80211_sdata_running(sdata))
449 			continue;
450 
451 		if (rcu_access_pointer(sdata->vif.chanctx_conf) !=
452 						&chanctx->conf)
453 			continue;
454 
455 		switch (sdata->vif.type) {
456 		case NL80211_IFTYPE_P2P_DEVICE:
457 			continue;
458 		case NL80211_IFTYPE_STATION:
459 			if (!sdata->u.mgd.associated)
460 				continue;
461 			break;
462 		case NL80211_IFTYPE_AP_VLAN:
463 			continue;
464 		case NL80211_IFTYPE_AP:
465 		case NL80211_IFTYPE_ADHOC:
466 		case NL80211_IFTYPE_WDS:
467 		case NL80211_IFTYPE_MESH_POINT:
468 			break;
469 		default:
470 			WARN_ON_ONCE(1);
471 		}
472 
473 		switch (sdata->smps_mode) {
474 		default:
475 			WARN_ONCE(1, "Invalid SMPS mode %d\n",
476 				  sdata->smps_mode);
477 			/* fall through */
478 		case IEEE80211_SMPS_OFF:
479 			needed_static = sdata->needed_rx_chains;
480 			needed_dynamic = sdata->needed_rx_chains;
481 			break;
482 		case IEEE80211_SMPS_DYNAMIC:
483 			needed_static = 1;
484 			needed_dynamic = sdata->needed_rx_chains;
485 			break;
486 		case IEEE80211_SMPS_STATIC:
487 			needed_static = 1;
488 			needed_dynamic = 1;
489 			break;
490 		}
491 
492 		rx_chains_static = max(rx_chains_static, needed_static);
493 		rx_chains_dynamic = max(rx_chains_dynamic, needed_dynamic);
494 	}
495 
496 	/* Disable SMPS for the monitor interface */
497 	sdata = rcu_dereference(local->monitor_sdata);
498 	if (sdata &&
499 	    rcu_access_pointer(sdata->vif.chanctx_conf) == &chanctx->conf)
500 		rx_chains_dynamic = rx_chains_static = local->rx_chains;
501 
502 	rcu_read_unlock();
503 
504 	if (!local->use_chanctx) {
505 		if (rx_chains_static > 1)
506 			local->smps_mode = IEEE80211_SMPS_OFF;
507 		else if (rx_chains_dynamic > 1)
508 			local->smps_mode = IEEE80211_SMPS_DYNAMIC;
509 		else
510 			local->smps_mode = IEEE80211_SMPS_STATIC;
511 		ieee80211_hw_config(local, 0);
512 	}
513 
514 	if (rx_chains_static == chanctx->conf.rx_chains_static &&
515 	    rx_chains_dynamic == chanctx->conf.rx_chains_dynamic)
516 		return;
517 
518 	chanctx->conf.rx_chains_static = rx_chains_static;
519 	chanctx->conf.rx_chains_dynamic = rx_chains_dynamic;
520 	drv_change_chanctx(local, chanctx, IEEE80211_CHANCTX_CHANGE_RX_CHAINS);
521 }
522 
523 int ieee80211_vif_use_channel(struct ieee80211_sub_if_data *sdata,
524 			      const struct cfg80211_chan_def *chandef,
525 			      enum ieee80211_chanctx_mode mode)
526 {
527 	struct ieee80211_local *local = sdata->local;
528 	struct ieee80211_chanctx *ctx;
529 	int ret;
530 
531 	lockdep_assert_held(&local->mtx);
532 
533 	WARN_ON(sdata->dev && netif_carrier_ok(sdata->dev));
534 
535 	mutex_lock(&local->chanctx_mtx);
536 	__ieee80211_vif_release_channel(sdata);
537 
538 	ctx = ieee80211_find_chanctx(local, chandef, mode);
539 	if (!ctx)
540 		ctx = ieee80211_new_chanctx(local, chandef, mode);
541 	if (IS_ERR(ctx)) {
542 		ret = PTR_ERR(ctx);
543 		goto out;
544 	}
545 
546 	sdata->vif.bss_conf.chandef = *chandef;
547 
548 	ret = ieee80211_assign_vif_chanctx(sdata, ctx);
549 	if (ret) {
550 		/* if assign fails refcount stays the same */
551 		if (ctx->refcount == 0)
552 			ieee80211_free_chanctx(local, ctx);
553 		goto out;
554 	}
555 
556 	ieee80211_recalc_smps_chanctx(local, ctx);
557 	ieee80211_recalc_radar_chanctx(local, ctx);
558  out:
559 	mutex_unlock(&local->chanctx_mtx);
560 	return ret;
561 }
562 
563 int ieee80211_vif_change_channel(struct ieee80211_sub_if_data *sdata,
564 				 u32 *changed)
565 {
566 	struct ieee80211_local *local = sdata->local;
567 	struct ieee80211_chanctx_conf *conf;
568 	struct ieee80211_chanctx *ctx;
569 	const struct cfg80211_chan_def *chandef = &sdata->csa_chandef;
570 	int ret;
571 	u32 chanctx_changed = 0;
572 
573 	lockdep_assert_held(&local->mtx);
574 
575 	/* should never be called if not performing a channel switch. */
576 	if (WARN_ON(!sdata->vif.csa_active))
577 		return -EINVAL;
578 
579 	if (!cfg80211_chandef_usable(sdata->local->hw.wiphy, chandef,
580 				     IEEE80211_CHAN_DISABLED))
581 		return -EINVAL;
582 
583 	mutex_lock(&local->chanctx_mtx);
584 	conf = rcu_dereference_protected(sdata->vif.chanctx_conf,
585 					 lockdep_is_held(&local->chanctx_mtx));
586 	if (!conf) {
587 		ret = -EINVAL;
588 		goto out;
589 	}
590 
591 	ctx = container_of(conf, struct ieee80211_chanctx, conf);
592 	if (ctx->refcount != 1) {
593 		ret = -EINVAL;
594 		goto out;
595 	}
596 
597 	if (sdata->vif.bss_conf.chandef.width != chandef->width) {
598 		chanctx_changed = IEEE80211_CHANCTX_CHANGE_WIDTH;
599 		*changed |= BSS_CHANGED_BANDWIDTH;
600 	}
601 
602 	sdata->vif.bss_conf.chandef = *chandef;
603 	ctx->conf.def = *chandef;
604 
605 	chanctx_changed |= IEEE80211_CHANCTX_CHANGE_CHANNEL;
606 	drv_change_chanctx(local, ctx, chanctx_changed);
607 
608 	ieee80211_recalc_chanctx_chantype(local, ctx);
609 	ieee80211_recalc_smps_chanctx(local, ctx);
610 	ieee80211_recalc_radar_chanctx(local, ctx);
611 	ieee80211_recalc_chanctx_min_def(local, ctx);
612 
613 	ret = 0;
614  out:
615 	mutex_unlock(&local->chanctx_mtx);
616 	return ret;
617 }
618 
619 int ieee80211_vif_change_bandwidth(struct ieee80211_sub_if_data *sdata,
620 				   const struct cfg80211_chan_def *chandef,
621 				   u32 *changed)
622 {
623 	struct ieee80211_local *local = sdata->local;
624 	struct ieee80211_chanctx_conf *conf;
625 	struct ieee80211_chanctx *ctx;
626 	int ret;
627 
628 	if (!cfg80211_chandef_usable(sdata->local->hw.wiphy, chandef,
629 				     IEEE80211_CHAN_DISABLED))
630 		return -EINVAL;
631 
632 	mutex_lock(&local->chanctx_mtx);
633 	if (cfg80211_chandef_identical(chandef, &sdata->vif.bss_conf.chandef)) {
634 		ret = 0;
635 		goto out;
636 	}
637 
638 	if (chandef->width == NL80211_CHAN_WIDTH_20_NOHT ||
639 	    sdata->vif.bss_conf.chandef.width == NL80211_CHAN_WIDTH_20_NOHT) {
640 		ret = -EINVAL;
641 		goto out;
642 	}
643 
644 	conf = rcu_dereference_protected(sdata->vif.chanctx_conf,
645 					 lockdep_is_held(&local->chanctx_mtx));
646 	if (!conf) {
647 		ret = -EINVAL;
648 		goto out;
649 	}
650 
651 	ctx = container_of(conf, struct ieee80211_chanctx, conf);
652 	if (!cfg80211_chandef_compatible(&conf->def, chandef)) {
653 		ret = -EINVAL;
654 		goto out;
655 	}
656 
657 	sdata->vif.bss_conf.chandef = *chandef;
658 
659 	ieee80211_recalc_chanctx_chantype(local, ctx);
660 
661 	*changed |= BSS_CHANGED_BANDWIDTH;
662 	ret = 0;
663  out:
664 	mutex_unlock(&local->chanctx_mtx);
665 	return ret;
666 }
667 
668 void ieee80211_vif_release_channel(struct ieee80211_sub_if_data *sdata)
669 {
670 	WARN_ON(sdata->dev && netif_carrier_ok(sdata->dev));
671 
672 	lockdep_assert_held(&sdata->local->mtx);
673 
674 	mutex_lock(&sdata->local->chanctx_mtx);
675 	__ieee80211_vif_release_channel(sdata);
676 	mutex_unlock(&sdata->local->chanctx_mtx);
677 }
678 
679 void ieee80211_vif_vlan_copy_chanctx(struct ieee80211_sub_if_data *sdata)
680 {
681 	struct ieee80211_local *local = sdata->local;
682 	struct ieee80211_sub_if_data *ap;
683 	struct ieee80211_chanctx_conf *conf;
684 
685 	if (WARN_ON(sdata->vif.type != NL80211_IFTYPE_AP_VLAN || !sdata->bss))
686 		return;
687 
688 	ap = container_of(sdata->bss, struct ieee80211_sub_if_data, u.ap);
689 
690 	mutex_lock(&local->chanctx_mtx);
691 
692 	conf = rcu_dereference_protected(ap->vif.chanctx_conf,
693 					 lockdep_is_held(&local->chanctx_mtx));
694 	rcu_assign_pointer(sdata->vif.chanctx_conf, conf);
695 	mutex_unlock(&local->chanctx_mtx);
696 }
697 
698 void ieee80211_vif_copy_chanctx_to_vlans(struct ieee80211_sub_if_data *sdata,
699 					 bool clear)
700 {
701 	struct ieee80211_local *local = sdata->local;
702 	struct ieee80211_sub_if_data *vlan;
703 	struct ieee80211_chanctx_conf *conf;
704 
705 	ASSERT_RTNL();
706 
707 	if (WARN_ON(sdata->vif.type != NL80211_IFTYPE_AP))
708 		return;
709 
710 	mutex_lock(&local->chanctx_mtx);
711 
712 	/*
713 	 * Check that conf exists, even when clearing this function
714 	 * must be called with the AP's channel context still there
715 	 * as it would otherwise cause VLANs to have an invalid
716 	 * channel context pointer for a while, possibly pointing
717 	 * to a channel context that has already been freed.
718 	 */
719 	conf = rcu_dereference_protected(sdata->vif.chanctx_conf,
720 				lockdep_is_held(&local->chanctx_mtx));
721 	WARN_ON(!conf);
722 
723 	if (clear)
724 		conf = NULL;
725 
726 	list_for_each_entry(vlan, &sdata->u.ap.vlans, u.vlan.list)
727 		rcu_assign_pointer(vlan->vif.chanctx_conf, conf);
728 
729 	mutex_unlock(&local->chanctx_mtx);
730 }
731 
732 void ieee80211_iter_chan_contexts_atomic(
733 	struct ieee80211_hw *hw,
734 	void (*iter)(struct ieee80211_hw *hw,
735 		     struct ieee80211_chanctx_conf *chanctx_conf,
736 		     void *data),
737 	void *iter_data)
738 {
739 	struct ieee80211_local *local = hw_to_local(hw);
740 	struct ieee80211_chanctx *ctx;
741 
742 	rcu_read_lock();
743 	list_for_each_entry_rcu(ctx, &local->chanctx_list, list)
744 		if (ctx->driver_present)
745 			iter(hw, &ctx->conf, iter_data);
746 	rcu_read_unlock();
747 }
748 EXPORT_SYMBOL_GPL(ieee80211_iter_chan_contexts_atomic);
749