xref: /linux/net/mac80211/chan.c (revision c4101e55974cc7d835fbd2d8e01553a3f61e9e75)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * mac80211 - channel management
4  * Copyright 2020 - 2022 Intel Corporation
5  */
6 
7 #include <linux/nl80211.h>
8 #include <linux/export.h>
9 #include <linux/rtnetlink.h>
10 #include <net/cfg80211.h>
11 #include "ieee80211_i.h"
12 #include "driver-ops.h"
13 #include "rate.h"
14 
15 static int ieee80211_chanctx_num_assigned(struct ieee80211_local *local,
16 					  struct ieee80211_chanctx *ctx)
17 {
18 	struct ieee80211_link_data *link;
19 	int num = 0;
20 
21 	lockdep_assert_wiphy(local->hw.wiphy);
22 
23 	list_for_each_entry(link, &ctx->assigned_links, assigned_chanctx_list)
24 		num++;
25 
26 	return num;
27 }
28 
29 static int ieee80211_chanctx_num_reserved(struct ieee80211_local *local,
30 					  struct ieee80211_chanctx *ctx)
31 {
32 	struct ieee80211_link_data *link;
33 	int num = 0;
34 
35 	lockdep_assert_wiphy(local->hw.wiphy);
36 
37 	list_for_each_entry(link, &ctx->reserved_links, reserved_chanctx_list)
38 		num++;
39 
40 	return num;
41 }
42 
43 int ieee80211_chanctx_refcount(struct ieee80211_local *local,
44 			       struct ieee80211_chanctx *ctx)
45 {
46 	return ieee80211_chanctx_num_assigned(local, ctx) +
47 	       ieee80211_chanctx_num_reserved(local, ctx);
48 }
49 
50 static int ieee80211_num_chanctx(struct ieee80211_local *local)
51 {
52 	struct ieee80211_chanctx *ctx;
53 	int num = 0;
54 
55 	lockdep_assert_wiphy(local->hw.wiphy);
56 
57 	list_for_each_entry(ctx, &local->chanctx_list, list)
58 		num++;
59 
60 	return num;
61 }
62 
63 static bool ieee80211_can_create_new_chanctx(struct ieee80211_local *local)
64 {
65 	lockdep_assert_wiphy(local->hw.wiphy);
66 
67 	return ieee80211_num_chanctx(local) < ieee80211_max_num_channels(local);
68 }
69 
70 static struct ieee80211_chanctx *
71 ieee80211_link_get_chanctx(struct ieee80211_link_data *link)
72 {
73 	struct ieee80211_local *local __maybe_unused = link->sdata->local;
74 	struct ieee80211_chanctx_conf *conf;
75 
76 	conf = rcu_dereference_protected(link->conf->chanctx_conf,
77 					 lockdep_is_held(&local->hw.wiphy->mtx));
78 	if (!conf)
79 		return NULL;
80 
81 	return container_of(conf, struct ieee80211_chanctx, conf);
82 }
83 
84 static const struct cfg80211_chan_def *
85 ieee80211_chanctx_reserved_chandef(struct ieee80211_local *local,
86 				   struct ieee80211_chanctx *ctx,
87 				   const struct cfg80211_chan_def *compat)
88 {
89 	struct ieee80211_link_data *link;
90 
91 	lockdep_assert_wiphy(local->hw.wiphy);
92 
93 	list_for_each_entry(link, &ctx->reserved_links,
94 			    reserved_chanctx_list) {
95 		if (!compat)
96 			compat = &link->reserved_chandef;
97 
98 		compat = cfg80211_chandef_compatible(&link->reserved_chandef,
99 						     compat);
100 		if (!compat)
101 			break;
102 	}
103 
104 	return compat;
105 }
106 
107 static const struct cfg80211_chan_def *
108 ieee80211_chanctx_non_reserved_chandef(struct ieee80211_local *local,
109 				       struct ieee80211_chanctx *ctx,
110 				       const struct cfg80211_chan_def *compat)
111 {
112 	struct ieee80211_link_data *link;
113 
114 	lockdep_assert_wiphy(local->hw.wiphy);
115 
116 	list_for_each_entry(link, &ctx->assigned_links,
117 			    assigned_chanctx_list) {
118 		struct ieee80211_bss_conf *link_conf = link->conf;
119 
120 		if (link->reserved_chanctx)
121 			continue;
122 
123 		if (!compat)
124 			compat = &link_conf->chandef;
125 
126 		compat = cfg80211_chandef_compatible(
127 				&link_conf->chandef, compat);
128 		if (!compat)
129 			break;
130 	}
131 
132 	return compat;
133 }
134 
135 static const struct cfg80211_chan_def *
136 ieee80211_chanctx_combined_chandef(struct ieee80211_local *local,
137 				   struct ieee80211_chanctx *ctx,
138 				   const struct cfg80211_chan_def *compat)
139 {
140 	lockdep_assert_wiphy(local->hw.wiphy);
141 
142 	compat = ieee80211_chanctx_reserved_chandef(local, ctx, compat);
143 	if (!compat)
144 		return NULL;
145 
146 	compat = ieee80211_chanctx_non_reserved_chandef(local, ctx, compat);
147 	if (!compat)
148 		return NULL;
149 
150 	return compat;
151 }
152 
153 static bool
154 ieee80211_chanctx_can_reserve_chandef(struct ieee80211_local *local,
155 				      struct ieee80211_chanctx *ctx,
156 				      const struct cfg80211_chan_def *def)
157 {
158 	lockdep_assert_wiphy(local->hw.wiphy);
159 
160 	if (ieee80211_chanctx_combined_chandef(local, ctx, def))
161 		return true;
162 
163 	if (!list_empty(&ctx->reserved_links) &&
164 	    ieee80211_chanctx_reserved_chandef(local, ctx, def))
165 		return true;
166 
167 	return false;
168 }
169 
170 static struct ieee80211_chanctx *
171 ieee80211_find_reservation_chanctx(struct ieee80211_local *local,
172 				   const struct cfg80211_chan_def *chandef,
173 				   enum ieee80211_chanctx_mode mode)
174 {
175 	struct ieee80211_chanctx *ctx;
176 
177 	lockdep_assert_wiphy(local->hw.wiphy);
178 
179 	if (mode == IEEE80211_CHANCTX_EXCLUSIVE)
180 		return NULL;
181 
182 	list_for_each_entry(ctx, &local->chanctx_list, list) {
183 		if (ctx->replace_state == IEEE80211_CHANCTX_WILL_BE_REPLACED)
184 			continue;
185 
186 		if (ctx->mode == IEEE80211_CHANCTX_EXCLUSIVE)
187 			continue;
188 
189 		if (!ieee80211_chanctx_can_reserve_chandef(local, ctx,
190 							   chandef))
191 			continue;
192 
193 		return ctx;
194 	}
195 
196 	return NULL;
197 }
198 
199 static enum nl80211_chan_width ieee80211_get_sta_bw(struct sta_info *sta,
200 						    unsigned int link_id)
201 {
202 	enum ieee80211_sta_rx_bandwidth width;
203 	struct link_sta_info *link_sta;
204 
205 	link_sta = rcu_dereference(sta->link[link_id]);
206 
207 	/* no effect if this STA has no presence on this link */
208 	if (!link_sta)
209 		return NL80211_CHAN_WIDTH_20_NOHT;
210 
211 	width = ieee80211_sta_cap_rx_bw(link_sta);
212 
213 	switch (width) {
214 	case IEEE80211_STA_RX_BW_20:
215 		if (link_sta->pub->ht_cap.ht_supported)
216 			return NL80211_CHAN_WIDTH_20;
217 		else
218 			return NL80211_CHAN_WIDTH_20_NOHT;
219 	case IEEE80211_STA_RX_BW_40:
220 		return NL80211_CHAN_WIDTH_40;
221 	case IEEE80211_STA_RX_BW_80:
222 		return NL80211_CHAN_WIDTH_80;
223 	case IEEE80211_STA_RX_BW_160:
224 		/*
225 		 * This applied for both 160 and 80+80. since we use
226 		 * the returned value to consider degradation of
227 		 * ctx->conf.min_def, we have to make sure to take
228 		 * the bigger one (NL80211_CHAN_WIDTH_160).
229 		 * Otherwise we might try degrading even when not
230 		 * needed, as the max required sta_bw returned (80+80)
231 		 * might be smaller than the configured bw (160).
232 		 */
233 		return NL80211_CHAN_WIDTH_160;
234 	case IEEE80211_STA_RX_BW_320:
235 		return NL80211_CHAN_WIDTH_320;
236 	default:
237 		WARN_ON(1);
238 		return NL80211_CHAN_WIDTH_20;
239 	}
240 }
241 
242 static enum nl80211_chan_width
243 ieee80211_get_max_required_bw(struct ieee80211_sub_if_data *sdata,
244 			      unsigned int link_id)
245 {
246 	enum nl80211_chan_width max_bw = NL80211_CHAN_WIDTH_20_NOHT;
247 	struct sta_info *sta;
248 
249 	list_for_each_entry_rcu(sta, &sdata->local->sta_list, list) {
250 		if (sdata != sta->sdata &&
251 		    !(sta->sdata->bss && sta->sdata->bss == sdata->bss))
252 			continue;
253 
254 		max_bw = max(max_bw, ieee80211_get_sta_bw(sta, link_id));
255 	}
256 
257 	return max_bw;
258 }
259 
260 static enum nl80211_chan_width
261 ieee80211_get_chanctx_vif_max_required_bw(struct ieee80211_sub_if_data *sdata,
262 					  struct ieee80211_chanctx *ctx,
263 					  struct ieee80211_link_data *rsvd_for)
264 {
265 	enum nl80211_chan_width max_bw = NL80211_CHAN_WIDTH_20_NOHT;
266 	struct ieee80211_vif *vif = &sdata->vif;
267 	int link_id;
268 
269 	rcu_read_lock();
270 	for (link_id = 0; link_id < ARRAY_SIZE(sdata->link); link_id++) {
271 		enum nl80211_chan_width width = NL80211_CHAN_WIDTH_20_NOHT;
272 		struct ieee80211_link_data *link =
273 			rcu_dereference(sdata->link[link_id]);
274 
275 		if (!link)
276 			continue;
277 
278 		if (link != rsvd_for &&
279 		    rcu_access_pointer(link->conf->chanctx_conf) != &ctx->conf)
280 			continue;
281 
282 		switch (vif->type) {
283 		case NL80211_IFTYPE_AP:
284 		case NL80211_IFTYPE_AP_VLAN:
285 			width = ieee80211_get_max_required_bw(sdata, link_id);
286 			break;
287 		case NL80211_IFTYPE_STATION:
288 			/*
289 			 * The ap's sta->bandwidth is not set yet at this
290 			 * point, so take the width from the chandef, but
291 			 * account also for TDLS peers
292 			 */
293 			width = max(link->conf->chandef.width,
294 				    ieee80211_get_max_required_bw(sdata, link_id));
295 			break;
296 		case NL80211_IFTYPE_P2P_DEVICE:
297 		case NL80211_IFTYPE_NAN:
298 			continue;
299 		case NL80211_IFTYPE_ADHOC:
300 		case NL80211_IFTYPE_MESH_POINT:
301 		case NL80211_IFTYPE_OCB:
302 			width = link->conf->chandef.width;
303 			break;
304 		case NL80211_IFTYPE_WDS:
305 		case NL80211_IFTYPE_UNSPECIFIED:
306 		case NUM_NL80211_IFTYPES:
307 		case NL80211_IFTYPE_MONITOR:
308 		case NL80211_IFTYPE_P2P_CLIENT:
309 		case NL80211_IFTYPE_P2P_GO:
310 			WARN_ON_ONCE(1);
311 		}
312 
313 		max_bw = max(max_bw, width);
314 	}
315 	rcu_read_unlock();
316 
317 	return max_bw;
318 }
319 
320 static enum nl80211_chan_width
321 ieee80211_get_chanctx_max_required_bw(struct ieee80211_local *local,
322 				      struct ieee80211_chanctx *ctx,
323 				      struct ieee80211_link_data *rsvd_for)
324 {
325 	struct ieee80211_sub_if_data *sdata;
326 	enum nl80211_chan_width max_bw = NL80211_CHAN_WIDTH_20_NOHT;
327 
328 	rcu_read_lock();
329 	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
330 		enum nl80211_chan_width width;
331 
332 		if (!ieee80211_sdata_running(sdata))
333 			continue;
334 
335 		width = ieee80211_get_chanctx_vif_max_required_bw(sdata, ctx,
336 								  rsvd_for);
337 
338 		max_bw = max(max_bw, width);
339 	}
340 
341 	/* use the configured bandwidth in case of monitor interface */
342 	sdata = rcu_dereference(local->monitor_sdata);
343 	if (sdata &&
344 	    rcu_access_pointer(sdata->vif.bss_conf.chanctx_conf) == &ctx->conf)
345 		max_bw = max(max_bw, ctx->conf.def.width);
346 
347 	rcu_read_unlock();
348 
349 	return max_bw;
350 }
351 
352 /*
353  * recalc the min required chan width of the channel context, which is
354  * the max of min required widths of all the interfaces bound to this
355  * channel context.
356  */
357 static u32
358 _ieee80211_recalc_chanctx_min_def(struct ieee80211_local *local,
359 				  struct ieee80211_chanctx *ctx,
360 				  struct ieee80211_link_data *rsvd_for)
361 {
362 	enum nl80211_chan_width max_bw;
363 	struct cfg80211_chan_def min_def;
364 
365 	lockdep_assert_wiphy(local->hw.wiphy);
366 
367 	/* don't optimize non-20MHz based and radar_enabled confs */
368 	if (ctx->conf.def.width == NL80211_CHAN_WIDTH_5 ||
369 	    ctx->conf.def.width == NL80211_CHAN_WIDTH_10 ||
370 	    ctx->conf.def.width == NL80211_CHAN_WIDTH_1 ||
371 	    ctx->conf.def.width == NL80211_CHAN_WIDTH_2 ||
372 	    ctx->conf.def.width == NL80211_CHAN_WIDTH_4 ||
373 	    ctx->conf.def.width == NL80211_CHAN_WIDTH_8 ||
374 	    ctx->conf.def.width == NL80211_CHAN_WIDTH_16 ||
375 	    ctx->conf.radar_enabled) {
376 		ctx->conf.min_def = ctx->conf.def;
377 		return 0;
378 	}
379 
380 	max_bw = ieee80211_get_chanctx_max_required_bw(local, ctx, rsvd_for);
381 
382 	/* downgrade chandef up to max_bw */
383 	min_def = ctx->conf.def;
384 	while (min_def.width > max_bw)
385 		ieee80211_chandef_downgrade(&min_def);
386 
387 	if (cfg80211_chandef_identical(&ctx->conf.min_def, &min_def))
388 		return 0;
389 
390 	ctx->conf.min_def = min_def;
391 	if (!ctx->driver_present)
392 		return 0;
393 
394 	return IEEE80211_CHANCTX_CHANGE_MIN_WIDTH;
395 }
396 
397 /* calling this function is assuming that station vif is updated to
398  * lates changes by calling ieee80211_link_update_chandef
399  */
400 static void ieee80211_chan_bw_change(struct ieee80211_local *local,
401 				     struct ieee80211_chanctx *ctx,
402 				     bool narrowed)
403 {
404 	struct sta_info *sta;
405 	struct ieee80211_supported_band *sband =
406 		local->hw.wiphy->bands[ctx->conf.def.chan->band];
407 
408 	rcu_read_lock();
409 	list_for_each_entry_rcu(sta, &local->sta_list,
410 				list) {
411 		struct ieee80211_sub_if_data *sdata = sta->sdata;
412 		enum ieee80211_sta_rx_bandwidth new_sta_bw;
413 		unsigned int link_id;
414 
415 		if (!ieee80211_sdata_running(sta->sdata))
416 			continue;
417 
418 		for (link_id = 0; link_id < ARRAY_SIZE(sta->sdata->link); link_id++) {
419 			struct ieee80211_bss_conf *link_conf =
420 				rcu_dereference(sdata->vif.link_conf[link_id]);
421 			struct link_sta_info *link_sta;
422 
423 			if (!link_conf)
424 				continue;
425 
426 			if (rcu_access_pointer(link_conf->chanctx_conf) != &ctx->conf)
427 				continue;
428 
429 			link_sta = rcu_dereference(sta->link[link_id]);
430 			if (!link_sta)
431 				continue;
432 
433 			new_sta_bw = ieee80211_sta_cur_vht_bw(link_sta);
434 
435 			/* nothing change */
436 			if (new_sta_bw == link_sta->pub->bandwidth)
437 				continue;
438 
439 			/* vif changed to narrow BW and narrow BW for station wasn't
440 			 * requested or vise versa */
441 			if ((new_sta_bw < link_sta->pub->bandwidth) == !narrowed)
442 				continue;
443 
444 			link_sta->pub->bandwidth = new_sta_bw;
445 			rate_control_rate_update(local, sband, sta, link_id,
446 						 IEEE80211_RC_BW_CHANGED);
447 		}
448 	}
449 	rcu_read_unlock();
450 }
451 
452 /*
453  * recalc the min required chan width of the channel context, which is
454  * the max of min required widths of all the interfaces bound to this
455  * channel context.
456  */
457 void ieee80211_recalc_chanctx_min_def(struct ieee80211_local *local,
458 				      struct ieee80211_chanctx *ctx,
459 				      struct ieee80211_link_data *rsvd_for)
460 {
461 	u32 changed = _ieee80211_recalc_chanctx_min_def(local, ctx, rsvd_for);
462 
463 	if (!changed)
464 		return;
465 
466 	/* check is BW narrowed */
467 	ieee80211_chan_bw_change(local, ctx, true);
468 
469 	drv_change_chanctx(local, ctx, changed);
470 
471 	/* check is BW wider */
472 	ieee80211_chan_bw_change(local, ctx, false);
473 }
474 
475 static void _ieee80211_change_chanctx(struct ieee80211_local *local,
476 				      struct ieee80211_chanctx *ctx,
477 				      struct ieee80211_chanctx *old_ctx,
478 				      const struct cfg80211_chan_def *chandef,
479 				      struct ieee80211_link_data *rsvd_for)
480 {
481 	u32 changed;
482 
483 	/* expected to handle only 20/40/80/160/320 channel widths */
484 	switch (chandef->width) {
485 	case NL80211_CHAN_WIDTH_20_NOHT:
486 	case NL80211_CHAN_WIDTH_20:
487 	case NL80211_CHAN_WIDTH_40:
488 	case NL80211_CHAN_WIDTH_80:
489 	case NL80211_CHAN_WIDTH_80P80:
490 	case NL80211_CHAN_WIDTH_160:
491 	case NL80211_CHAN_WIDTH_320:
492 		break;
493 	default:
494 		WARN_ON(1);
495 	}
496 
497 	/* Check maybe BW narrowed - we do this _before_ calling recalc_chanctx_min_def
498 	 * due to maybe not returning from it, e.g in case new context was added
499 	 * first time with all parameters up to date.
500 	 */
501 	ieee80211_chan_bw_change(local, old_ctx, true);
502 
503 	if (cfg80211_chandef_identical(&ctx->conf.def, chandef)) {
504 		ieee80211_recalc_chanctx_min_def(local, ctx, rsvd_for);
505 		return;
506 	}
507 
508 	WARN_ON(!cfg80211_chandef_compatible(&ctx->conf.def, chandef));
509 
510 	ieee80211_remove_wbrf(local, &ctx->conf.def);
511 
512 	ctx->conf.def = *chandef;
513 
514 	/* check if min chanctx also changed */
515 	changed = IEEE80211_CHANCTX_CHANGE_WIDTH |
516 		  _ieee80211_recalc_chanctx_min_def(local, ctx, rsvd_for);
517 
518 	ieee80211_add_wbrf(local, &ctx->conf.def);
519 
520 	drv_change_chanctx(local, ctx, changed);
521 
522 	if (!local->use_chanctx) {
523 		local->_oper_chandef = *chandef;
524 		ieee80211_hw_config(local, 0);
525 	}
526 
527 	/* check is BW wider */
528 	ieee80211_chan_bw_change(local, old_ctx, false);
529 }
530 
531 static void ieee80211_change_chanctx(struct ieee80211_local *local,
532 				     struct ieee80211_chanctx *ctx,
533 				     struct ieee80211_chanctx *old_ctx,
534 				     const struct cfg80211_chan_def *chandef)
535 {
536 	_ieee80211_change_chanctx(local, ctx, old_ctx, chandef, NULL);
537 }
538 
539 static struct ieee80211_chanctx *
540 ieee80211_find_chanctx(struct ieee80211_local *local,
541 		       const struct cfg80211_chan_def *chandef,
542 		       enum ieee80211_chanctx_mode mode)
543 {
544 	struct ieee80211_chanctx *ctx;
545 
546 	lockdep_assert_wiphy(local->hw.wiphy);
547 
548 	if (mode == IEEE80211_CHANCTX_EXCLUSIVE)
549 		return NULL;
550 
551 	list_for_each_entry(ctx, &local->chanctx_list, list) {
552 		const struct cfg80211_chan_def *compat;
553 
554 		if (ctx->replace_state != IEEE80211_CHANCTX_REPLACE_NONE)
555 			continue;
556 
557 		if (ctx->mode == IEEE80211_CHANCTX_EXCLUSIVE)
558 			continue;
559 
560 		compat = cfg80211_chandef_compatible(&ctx->conf.def, chandef);
561 		if (!compat)
562 			continue;
563 
564 		compat = ieee80211_chanctx_reserved_chandef(local, ctx,
565 							    compat);
566 		if (!compat)
567 			continue;
568 
569 		ieee80211_change_chanctx(local, ctx, ctx, compat);
570 
571 		return ctx;
572 	}
573 
574 	return NULL;
575 }
576 
577 bool ieee80211_is_radar_required(struct ieee80211_local *local)
578 {
579 	struct ieee80211_sub_if_data *sdata;
580 
581 	lockdep_assert_wiphy(local->hw.wiphy);
582 
583 	rcu_read_lock();
584 	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
585 		unsigned int link_id;
586 
587 		for (link_id = 0; link_id < ARRAY_SIZE(sdata->link); link_id++) {
588 			struct ieee80211_link_data *link;
589 
590 			link = rcu_dereference(sdata->link[link_id]);
591 
592 			if (link && link->radar_required) {
593 				rcu_read_unlock();
594 				return true;
595 			}
596 		}
597 	}
598 	rcu_read_unlock();
599 
600 	return false;
601 }
602 
603 static bool
604 ieee80211_chanctx_radar_required(struct ieee80211_local *local,
605 				 struct ieee80211_chanctx *ctx)
606 {
607 	struct ieee80211_chanctx_conf *conf = &ctx->conf;
608 	struct ieee80211_sub_if_data *sdata;
609 	bool required = false;
610 
611 	lockdep_assert_wiphy(local->hw.wiphy);
612 
613 	rcu_read_lock();
614 	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
615 		unsigned int link_id;
616 
617 		if (!ieee80211_sdata_running(sdata))
618 			continue;
619 		for (link_id = 0; link_id < ARRAY_SIZE(sdata->link); link_id++) {
620 			struct ieee80211_link_data *link;
621 
622 			link = rcu_dereference(sdata->link[link_id]);
623 			if (!link)
624 				continue;
625 
626 			if (rcu_access_pointer(link->conf->chanctx_conf) != conf)
627 				continue;
628 			if (!link->radar_required)
629 				continue;
630 			required = true;
631 			break;
632 		}
633 
634 		if (required)
635 			break;
636 	}
637 	rcu_read_unlock();
638 
639 	return required;
640 }
641 
642 static struct ieee80211_chanctx *
643 ieee80211_alloc_chanctx(struct ieee80211_local *local,
644 			const struct cfg80211_chan_def *chandef,
645 			enum ieee80211_chanctx_mode mode)
646 {
647 	struct ieee80211_chanctx *ctx;
648 
649 	lockdep_assert_wiphy(local->hw.wiphy);
650 
651 	ctx = kzalloc(sizeof(*ctx) + local->hw.chanctx_data_size, GFP_KERNEL);
652 	if (!ctx)
653 		return NULL;
654 
655 	INIT_LIST_HEAD(&ctx->assigned_links);
656 	INIT_LIST_HEAD(&ctx->reserved_links);
657 	ctx->conf.def = *chandef;
658 	ctx->conf.rx_chains_static = 1;
659 	ctx->conf.rx_chains_dynamic = 1;
660 	ctx->mode = mode;
661 	ctx->conf.radar_enabled = false;
662 	_ieee80211_recalc_chanctx_min_def(local, ctx, NULL);
663 
664 	return ctx;
665 }
666 
667 static int ieee80211_add_chanctx(struct ieee80211_local *local,
668 				 struct ieee80211_chanctx *ctx)
669 {
670 	u32 changed;
671 	int err;
672 
673 	lockdep_assert_wiphy(local->hw.wiphy);
674 
675 	ieee80211_add_wbrf(local, &ctx->conf.def);
676 
677 	if (!local->use_chanctx)
678 		local->hw.conf.radar_enabled = ctx->conf.radar_enabled;
679 
680 	/* turn idle off *before* setting channel -- some drivers need that */
681 	changed = ieee80211_idle_off(local);
682 	if (changed)
683 		ieee80211_hw_config(local, changed);
684 
685 	if (!local->use_chanctx) {
686 		local->_oper_chandef = ctx->conf.def;
687 		ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
688 	} else {
689 		err = drv_add_chanctx(local, ctx);
690 		if (err) {
691 			ieee80211_recalc_idle(local);
692 			return err;
693 		}
694 	}
695 
696 	return 0;
697 }
698 
699 static struct ieee80211_chanctx *
700 ieee80211_new_chanctx(struct ieee80211_local *local,
701 		      const struct cfg80211_chan_def *chandef,
702 		      enum ieee80211_chanctx_mode mode)
703 {
704 	struct ieee80211_chanctx *ctx;
705 	int err;
706 
707 	lockdep_assert_wiphy(local->hw.wiphy);
708 
709 	ctx = ieee80211_alloc_chanctx(local, chandef, mode);
710 	if (!ctx)
711 		return ERR_PTR(-ENOMEM);
712 
713 	err = ieee80211_add_chanctx(local, ctx);
714 	if (err) {
715 		kfree(ctx);
716 		return ERR_PTR(err);
717 	}
718 
719 	list_add_rcu(&ctx->list, &local->chanctx_list);
720 	return ctx;
721 }
722 
723 static void ieee80211_del_chanctx(struct ieee80211_local *local,
724 				  struct ieee80211_chanctx *ctx)
725 {
726 	lockdep_assert_wiphy(local->hw.wiphy);
727 
728 	if (!local->use_chanctx) {
729 		struct cfg80211_chan_def *chandef = &local->_oper_chandef;
730 		/* S1G doesn't have 20MHz, so get the correct width for the
731 		 * current channel.
732 		 */
733 		if (chandef->chan->band == NL80211_BAND_S1GHZ)
734 			chandef->width =
735 				ieee80211_s1g_channel_width(chandef->chan);
736 		else
737 			chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
738 		chandef->center_freq1 = chandef->chan->center_freq;
739 		chandef->freq1_offset = chandef->chan->freq_offset;
740 		chandef->center_freq2 = 0;
741 
742 		/* NOTE: Disabling radar is only valid here for
743 		 * single channel context. To be sure, check it ...
744 		 */
745 		WARN_ON(local->hw.conf.radar_enabled &&
746 			!list_empty(&local->chanctx_list));
747 
748 		local->hw.conf.radar_enabled = false;
749 
750 		ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
751 	} else {
752 		drv_remove_chanctx(local, ctx);
753 	}
754 
755 	ieee80211_recalc_idle(local);
756 
757 	ieee80211_remove_wbrf(local, &ctx->conf.def);
758 }
759 
760 static void ieee80211_free_chanctx(struct ieee80211_local *local,
761 				   struct ieee80211_chanctx *ctx)
762 {
763 	lockdep_assert_wiphy(local->hw.wiphy);
764 
765 	WARN_ON_ONCE(ieee80211_chanctx_refcount(local, ctx) != 0);
766 
767 	list_del_rcu(&ctx->list);
768 	ieee80211_del_chanctx(local, ctx);
769 	kfree_rcu(ctx, rcu_head);
770 }
771 
772 void ieee80211_recalc_chanctx_chantype(struct ieee80211_local *local,
773 				       struct ieee80211_chanctx *ctx)
774 {
775 	struct ieee80211_chanctx_conf *conf = &ctx->conf;
776 	struct ieee80211_sub_if_data *sdata;
777 	const struct cfg80211_chan_def *compat = NULL;
778 	struct sta_info *sta;
779 
780 	lockdep_assert_wiphy(local->hw.wiphy);
781 
782 	rcu_read_lock();
783 	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
784 		int link_id;
785 
786 		if (!ieee80211_sdata_running(sdata))
787 			continue;
788 
789 		if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
790 			continue;
791 
792 		for (link_id = 0; link_id < ARRAY_SIZE(sdata->link); link_id++) {
793 			struct ieee80211_bss_conf *link_conf =
794 				rcu_dereference(sdata->vif.link_conf[link_id]);
795 
796 			if (!link_conf)
797 				continue;
798 
799 			if (rcu_access_pointer(link_conf->chanctx_conf) != conf)
800 				continue;
801 
802 			if (!compat)
803 				compat = &link_conf->chandef;
804 
805 			compat = cfg80211_chandef_compatible(&link_conf->chandef,
806 							     compat);
807 			if (WARN_ON_ONCE(!compat))
808 				break;
809 		}
810 	}
811 
812 	if (WARN_ON_ONCE(!compat)) {
813 		rcu_read_unlock();
814 		return;
815 	}
816 
817 	/* TDLS peers can sometimes affect the chandef width */
818 	list_for_each_entry_rcu(sta, &local->sta_list, list) {
819 		if (!sta->uploaded ||
820 		    !test_sta_flag(sta, WLAN_STA_TDLS_WIDER_BW) ||
821 		    !test_sta_flag(sta, WLAN_STA_AUTHORIZED) ||
822 		    !sta->tdls_chandef.chan)
823 			continue;
824 
825 		compat = cfg80211_chandef_compatible(&sta->tdls_chandef,
826 						     compat);
827 		if (WARN_ON_ONCE(!compat))
828 			break;
829 	}
830 	rcu_read_unlock();
831 
832 	if (!compat)
833 		return;
834 
835 	ieee80211_change_chanctx(local, ctx, ctx, compat);
836 }
837 
838 static void ieee80211_recalc_radar_chanctx(struct ieee80211_local *local,
839 					   struct ieee80211_chanctx *chanctx)
840 {
841 	bool radar_enabled;
842 
843 	lockdep_assert_wiphy(local->hw.wiphy);
844 
845 	radar_enabled = ieee80211_chanctx_radar_required(local, chanctx);
846 
847 	if (radar_enabled == chanctx->conf.radar_enabled)
848 		return;
849 
850 	chanctx->conf.radar_enabled = radar_enabled;
851 
852 	if (!local->use_chanctx) {
853 		local->hw.conf.radar_enabled = chanctx->conf.radar_enabled;
854 		ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
855 	}
856 
857 	drv_change_chanctx(local, chanctx, IEEE80211_CHANCTX_CHANGE_RADAR);
858 }
859 
860 static int ieee80211_assign_link_chanctx(struct ieee80211_link_data *link,
861 					 struct ieee80211_chanctx *new_ctx)
862 {
863 	struct ieee80211_sub_if_data *sdata = link->sdata;
864 	struct ieee80211_local *local = sdata->local;
865 	struct ieee80211_chanctx_conf *conf;
866 	struct ieee80211_chanctx *curr_ctx = NULL;
867 	int ret = 0;
868 
869 	if (WARN_ON(sdata->vif.type == NL80211_IFTYPE_NAN))
870 		return -EOPNOTSUPP;
871 
872 	conf = rcu_dereference_protected(link->conf->chanctx_conf,
873 					 lockdep_is_held(&local->hw.wiphy->mtx));
874 
875 	if (conf) {
876 		curr_ctx = container_of(conf, struct ieee80211_chanctx, conf);
877 
878 		drv_unassign_vif_chanctx(local, sdata, link->conf, curr_ctx);
879 		conf = NULL;
880 		list_del(&link->assigned_chanctx_list);
881 	}
882 
883 	if (new_ctx) {
884 		/* recalc considering the link we'll use it for now */
885 		ieee80211_recalc_chanctx_min_def(local, new_ctx, link);
886 
887 		ret = drv_assign_vif_chanctx(local, sdata, link->conf, new_ctx);
888 		if (ret)
889 			goto out;
890 
891 		conf = &new_ctx->conf;
892 		list_add(&link->assigned_chanctx_list,
893 			 &new_ctx->assigned_links);
894 	}
895 
896 out:
897 	rcu_assign_pointer(link->conf->chanctx_conf, conf);
898 
899 	sdata->vif.cfg.idle = !conf;
900 
901 	if (curr_ctx && ieee80211_chanctx_num_assigned(local, curr_ctx) > 0) {
902 		ieee80211_recalc_chanctx_chantype(local, curr_ctx);
903 		ieee80211_recalc_smps_chanctx(local, curr_ctx);
904 		ieee80211_recalc_radar_chanctx(local, curr_ctx);
905 		ieee80211_recalc_chanctx_min_def(local, curr_ctx, NULL);
906 	}
907 
908 	if (new_ctx && ieee80211_chanctx_num_assigned(local, new_ctx) > 0) {
909 		ieee80211_recalc_txpower(sdata, false);
910 		ieee80211_recalc_chanctx_min_def(local, new_ctx, NULL);
911 	}
912 
913 	if (sdata->vif.type != NL80211_IFTYPE_P2P_DEVICE &&
914 	    sdata->vif.type != NL80211_IFTYPE_MONITOR)
915 		ieee80211_vif_cfg_change_notify(sdata, BSS_CHANGED_IDLE);
916 
917 	ieee80211_check_fast_xmit_iface(sdata);
918 
919 	return ret;
920 }
921 
922 void ieee80211_recalc_smps_chanctx(struct ieee80211_local *local,
923 				   struct ieee80211_chanctx *chanctx)
924 {
925 	struct ieee80211_sub_if_data *sdata;
926 	u8 rx_chains_static, rx_chains_dynamic;
927 
928 	lockdep_assert_wiphy(local->hw.wiphy);
929 
930 	rx_chains_static = 1;
931 	rx_chains_dynamic = 1;
932 
933 	rcu_read_lock();
934 	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
935 		u8 needed_static, needed_dynamic;
936 		unsigned int link_id;
937 
938 		if (!ieee80211_sdata_running(sdata))
939 			continue;
940 
941 		switch (sdata->vif.type) {
942 		case NL80211_IFTYPE_STATION:
943 			if (!sdata->u.mgd.associated)
944 				continue;
945 			break;
946 		case NL80211_IFTYPE_AP:
947 		case NL80211_IFTYPE_ADHOC:
948 		case NL80211_IFTYPE_MESH_POINT:
949 		case NL80211_IFTYPE_OCB:
950 			break;
951 		default:
952 			continue;
953 		}
954 
955 		for (link_id = 0; link_id < ARRAY_SIZE(sdata->link); link_id++) {
956 			struct ieee80211_link_data *link;
957 
958 			link = rcu_dereference(sdata->link[link_id]);
959 
960 			if (!link)
961 				continue;
962 
963 			if (rcu_access_pointer(link->conf->chanctx_conf) != &chanctx->conf)
964 				continue;
965 
966 			switch (link->smps_mode) {
967 			default:
968 				WARN_ONCE(1, "Invalid SMPS mode %d\n",
969 					  link->smps_mode);
970 				fallthrough;
971 			case IEEE80211_SMPS_OFF:
972 				needed_static = link->needed_rx_chains;
973 				needed_dynamic = link->needed_rx_chains;
974 				break;
975 			case IEEE80211_SMPS_DYNAMIC:
976 				needed_static = 1;
977 				needed_dynamic = link->needed_rx_chains;
978 				break;
979 			case IEEE80211_SMPS_STATIC:
980 				needed_static = 1;
981 				needed_dynamic = 1;
982 				break;
983 			}
984 
985 			rx_chains_static = max(rx_chains_static, needed_static);
986 			rx_chains_dynamic = max(rx_chains_dynamic, needed_dynamic);
987 		}
988 	}
989 
990 	/* Disable SMPS for the monitor interface */
991 	sdata = rcu_dereference(local->monitor_sdata);
992 	if (sdata &&
993 	    rcu_access_pointer(sdata->vif.bss_conf.chanctx_conf) == &chanctx->conf)
994 		rx_chains_dynamic = rx_chains_static = local->rx_chains;
995 
996 	rcu_read_unlock();
997 
998 	if (!local->use_chanctx) {
999 		if (rx_chains_static > 1)
1000 			local->smps_mode = IEEE80211_SMPS_OFF;
1001 		else if (rx_chains_dynamic > 1)
1002 			local->smps_mode = IEEE80211_SMPS_DYNAMIC;
1003 		else
1004 			local->smps_mode = IEEE80211_SMPS_STATIC;
1005 		ieee80211_hw_config(local, 0);
1006 	}
1007 
1008 	if (rx_chains_static == chanctx->conf.rx_chains_static &&
1009 	    rx_chains_dynamic == chanctx->conf.rx_chains_dynamic)
1010 		return;
1011 
1012 	chanctx->conf.rx_chains_static = rx_chains_static;
1013 	chanctx->conf.rx_chains_dynamic = rx_chains_dynamic;
1014 	drv_change_chanctx(local, chanctx, IEEE80211_CHANCTX_CHANGE_RX_CHAINS);
1015 }
1016 
1017 static void
1018 __ieee80211_link_copy_chanctx_to_vlans(struct ieee80211_link_data *link,
1019 				       bool clear)
1020 {
1021 	struct ieee80211_sub_if_data *sdata = link->sdata;
1022 	unsigned int link_id = link->link_id;
1023 	struct ieee80211_bss_conf *link_conf = link->conf;
1024 	struct ieee80211_local *local __maybe_unused = sdata->local;
1025 	struct ieee80211_sub_if_data *vlan;
1026 	struct ieee80211_chanctx_conf *conf;
1027 
1028 	if (WARN_ON(sdata->vif.type != NL80211_IFTYPE_AP))
1029 		return;
1030 
1031 	lockdep_assert_wiphy(local->hw.wiphy);
1032 
1033 	/* Check that conf exists, even when clearing this function
1034 	 * must be called with the AP's channel context still there
1035 	 * as it would otherwise cause VLANs to have an invalid
1036 	 * channel context pointer for a while, possibly pointing
1037 	 * to a channel context that has already been freed.
1038 	 */
1039 	conf = rcu_dereference_protected(link_conf->chanctx_conf,
1040 					 lockdep_is_held(&local->hw.wiphy->mtx));
1041 	WARN_ON(!conf);
1042 
1043 	if (clear)
1044 		conf = NULL;
1045 
1046 	rcu_read_lock();
1047 	list_for_each_entry(vlan, &sdata->u.ap.vlans, u.vlan.list) {
1048 		struct ieee80211_bss_conf *vlan_conf;
1049 
1050 		vlan_conf = rcu_dereference(vlan->vif.link_conf[link_id]);
1051 		if (WARN_ON(!vlan_conf))
1052 			continue;
1053 
1054 		rcu_assign_pointer(vlan_conf->chanctx_conf, conf);
1055 	}
1056 	rcu_read_unlock();
1057 }
1058 
1059 void ieee80211_link_copy_chanctx_to_vlans(struct ieee80211_link_data *link,
1060 					  bool clear)
1061 {
1062 	struct ieee80211_local *local = link->sdata->local;
1063 
1064 	lockdep_assert_wiphy(local->hw.wiphy);
1065 
1066 	__ieee80211_link_copy_chanctx_to_vlans(link, clear);
1067 }
1068 
1069 int ieee80211_link_unreserve_chanctx(struct ieee80211_link_data *link)
1070 {
1071 	struct ieee80211_sub_if_data *sdata = link->sdata;
1072 	struct ieee80211_chanctx *ctx = link->reserved_chanctx;
1073 
1074 	lockdep_assert_wiphy(sdata->local->hw.wiphy);
1075 
1076 	if (WARN_ON(!ctx))
1077 		return -EINVAL;
1078 
1079 	list_del(&link->reserved_chanctx_list);
1080 	link->reserved_chanctx = NULL;
1081 
1082 	if (ieee80211_chanctx_refcount(sdata->local, ctx) == 0) {
1083 		if (ctx->replace_state == IEEE80211_CHANCTX_REPLACES_OTHER) {
1084 			if (WARN_ON(!ctx->replace_ctx))
1085 				return -EINVAL;
1086 
1087 			WARN_ON(ctx->replace_ctx->replace_state !=
1088 			        IEEE80211_CHANCTX_WILL_BE_REPLACED);
1089 			WARN_ON(ctx->replace_ctx->replace_ctx != ctx);
1090 
1091 			ctx->replace_ctx->replace_ctx = NULL;
1092 			ctx->replace_ctx->replace_state =
1093 					IEEE80211_CHANCTX_REPLACE_NONE;
1094 
1095 			list_del_rcu(&ctx->list);
1096 			kfree_rcu(ctx, rcu_head);
1097 		} else {
1098 			ieee80211_free_chanctx(sdata->local, ctx);
1099 		}
1100 	}
1101 
1102 	return 0;
1103 }
1104 
1105 int ieee80211_link_reserve_chanctx(struct ieee80211_link_data *link,
1106 				   const struct cfg80211_chan_def *chandef,
1107 				   enum ieee80211_chanctx_mode mode,
1108 				   bool radar_required)
1109 {
1110 	struct ieee80211_sub_if_data *sdata = link->sdata;
1111 	struct ieee80211_local *local = sdata->local;
1112 	struct ieee80211_chanctx *new_ctx, *curr_ctx, *ctx;
1113 
1114 	lockdep_assert_wiphy(local->hw.wiphy);
1115 
1116 	curr_ctx = ieee80211_link_get_chanctx(link);
1117 	if (curr_ctx && local->use_chanctx && !local->ops->switch_vif_chanctx)
1118 		return -EOPNOTSUPP;
1119 
1120 	new_ctx = ieee80211_find_reservation_chanctx(local, chandef, mode);
1121 	if (!new_ctx) {
1122 		if (ieee80211_can_create_new_chanctx(local)) {
1123 			new_ctx = ieee80211_new_chanctx(local, chandef, mode);
1124 			if (IS_ERR(new_ctx))
1125 				return PTR_ERR(new_ctx);
1126 		} else {
1127 			if (!curr_ctx ||
1128 			    (curr_ctx->replace_state ==
1129 			     IEEE80211_CHANCTX_WILL_BE_REPLACED) ||
1130 			    !list_empty(&curr_ctx->reserved_links)) {
1131 				/*
1132 				 * Another link already requested this context
1133 				 * for a reservation. Find another one hoping
1134 				 * all links assigned to it will also switch
1135 				 * soon enough.
1136 				 *
1137 				 * TODO: This needs a little more work as some
1138 				 * cases (more than 2 chanctx capable devices)
1139 				 * may fail which could otherwise succeed
1140 				 * provided some channel context juggling was
1141 				 * performed.
1142 				 *
1143 				 * Consider ctx1..3, link1..6, each ctx has 2
1144 				 * links. link1 and link2 from ctx1 request new
1145 				 * different chandefs starting 2 in-place
1146 				 * reserations with ctx4 and ctx5 replacing
1147 				 * ctx1 and ctx2 respectively. Next link5 and
1148 				 * link6 from ctx3 reserve ctx4. If link3 and
1149 				 * link4 remain on ctx2 as they are then this
1150 				 * fails unless `replace_ctx` from ctx5 is
1151 				 * replaced with ctx3.
1152 				 */
1153 				list_for_each_entry(ctx, &local->chanctx_list,
1154 						    list) {
1155 					if (ctx->replace_state !=
1156 					    IEEE80211_CHANCTX_REPLACE_NONE)
1157 						continue;
1158 
1159 					if (!list_empty(&ctx->reserved_links))
1160 						continue;
1161 
1162 					curr_ctx = ctx;
1163 					break;
1164 				}
1165 			}
1166 
1167 			/*
1168 			 * If that's true then all available contexts already
1169 			 * have reservations and cannot be used.
1170 			 */
1171 			if (!curr_ctx ||
1172 			    (curr_ctx->replace_state ==
1173 			     IEEE80211_CHANCTX_WILL_BE_REPLACED) ||
1174 			    !list_empty(&curr_ctx->reserved_links))
1175 				return -EBUSY;
1176 
1177 			new_ctx = ieee80211_alloc_chanctx(local, chandef, mode);
1178 			if (!new_ctx)
1179 				return -ENOMEM;
1180 
1181 			new_ctx->replace_ctx = curr_ctx;
1182 			new_ctx->replace_state =
1183 					IEEE80211_CHANCTX_REPLACES_OTHER;
1184 
1185 			curr_ctx->replace_ctx = new_ctx;
1186 			curr_ctx->replace_state =
1187 					IEEE80211_CHANCTX_WILL_BE_REPLACED;
1188 
1189 			list_add_rcu(&new_ctx->list, &local->chanctx_list);
1190 		}
1191 	}
1192 
1193 	list_add(&link->reserved_chanctx_list, &new_ctx->reserved_links);
1194 	link->reserved_chanctx = new_ctx;
1195 	link->reserved_chandef = *chandef;
1196 	link->reserved_radar_required = radar_required;
1197 	link->reserved_ready = false;
1198 
1199 	return 0;
1200 }
1201 
1202 static void
1203 ieee80211_link_chanctx_reservation_complete(struct ieee80211_link_data *link)
1204 {
1205 	struct ieee80211_sub_if_data *sdata = link->sdata;
1206 
1207 	switch (sdata->vif.type) {
1208 	case NL80211_IFTYPE_ADHOC:
1209 	case NL80211_IFTYPE_AP:
1210 	case NL80211_IFTYPE_MESH_POINT:
1211 	case NL80211_IFTYPE_OCB:
1212 		wiphy_work_queue(sdata->local->hw.wiphy,
1213 				 &link->csa_finalize_work);
1214 		break;
1215 	case NL80211_IFTYPE_STATION:
1216 		wiphy_delayed_work_queue(sdata->local->hw.wiphy,
1217 					 &link->u.mgd.chswitch_work, 0);
1218 		break;
1219 	case NL80211_IFTYPE_UNSPECIFIED:
1220 	case NL80211_IFTYPE_AP_VLAN:
1221 	case NL80211_IFTYPE_WDS:
1222 	case NL80211_IFTYPE_MONITOR:
1223 	case NL80211_IFTYPE_P2P_CLIENT:
1224 	case NL80211_IFTYPE_P2P_GO:
1225 	case NL80211_IFTYPE_P2P_DEVICE:
1226 	case NL80211_IFTYPE_NAN:
1227 	case NUM_NL80211_IFTYPES:
1228 		WARN_ON(1);
1229 		break;
1230 	}
1231 }
1232 
1233 static void
1234 ieee80211_link_update_chandef(struct ieee80211_link_data *link,
1235 			      const struct cfg80211_chan_def *chandef)
1236 {
1237 	struct ieee80211_sub_if_data *sdata = link->sdata;
1238 	unsigned int link_id = link->link_id;
1239 	struct ieee80211_sub_if_data *vlan;
1240 
1241 	link->conf->chandef = *chandef;
1242 
1243 	if (sdata->vif.type != NL80211_IFTYPE_AP)
1244 		return;
1245 
1246 	rcu_read_lock();
1247 	list_for_each_entry(vlan, &sdata->u.ap.vlans, u.vlan.list) {
1248 		struct ieee80211_bss_conf *vlan_conf;
1249 
1250 		vlan_conf = rcu_dereference(vlan->vif.link_conf[link_id]);
1251 		if (WARN_ON(!vlan_conf))
1252 			continue;
1253 
1254 		vlan_conf->chandef = *chandef;
1255 	}
1256 	rcu_read_unlock();
1257 }
1258 
1259 static int
1260 ieee80211_link_use_reserved_reassign(struct ieee80211_link_data *link)
1261 {
1262 	struct ieee80211_sub_if_data *sdata = link->sdata;
1263 	struct ieee80211_bss_conf *link_conf = link->conf;
1264 	struct ieee80211_local *local = sdata->local;
1265 	struct ieee80211_vif_chanctx_switch vif_chsw[1] = {};
1266 	struct ieee80211_chanctx *old_ctx, *new_ctx;
1267 	const struct cfg80211_chan_def *chandef;
1268 	u64 changed = 0;
1269 	int err;
1270 
1271 	lockdep_assert_wiphy(local->hw.wiphy);
1272 
1273 	new_ctx = link->reserved_chanctx;
1274 	old_ctx = ieee80211_link_get_chanctx(link);
1275 
1276 	if (WARN_ON(!link->reserved_ready))
1277 		return -EBUSY;
1278 
1279 	if (WARN_ON(!new_ctx))
1280 		return -EINVAL;
1281 
1282 	if (WARN_ON(!old_ctx))
1283 		return -EINVAL;
1284 
1285 	if (WARN_ON(new_ctx->replace_state ==
1286 		    IEEE80211_CHANCTX_REPLACES_OTHER))
1287 		return -EINVAL;
1288 
1289 	chandef = ieee80211_chanctx_non_reserved_chandef(local, new_ctx,
1290 				&link->reserved_chandef);
1291 	if (WARN_ON(!chandef))
1292 		return -EINVAL;
1293 
1294 	if (link_conf->chandef.width != link->reserved_chandef.width)
1295 		changed = BSS_CHANGED_BANDWIDTH;
1296 
1297 	ieee80211_link_update_chandef(link, &link->reserved_chandef);
1298 
1299 	_ieee80211_change_chanctx(local, new_ctx, old_ctx, chandef, link);
1300 
1301 	vif_chsw[0].vif = &sdata->vif;
1302 	vif_chsw[0].old_ctx = &old_ctx->conf;
1303 	vif_chsw[0].new_ctx = &new_ctx->conf;
1304 	vif_chsw[0].link_conf = link->conf;
1305 
1306 	list_del(&link->reserved_chanctx_list);
1307 	link->reserved_chanctx = NULL;
1308 
1309 	err = drv_switch_vif_chanctx(local, vif_chsw, 1,
1310 				     CHANCTX_SWMODE_REASSIGN_VIF);
1311 	if (err) {
1312 		if (ieee80211_chanctx_refcount(local, new_ctx) == 0)
1313 			ieee80211_free_chanctx(local, new_ctx);
1314 
1315 		goto out;
1316 	}
1317 
1318 	list_move(&link->assigned_chanctx_list, &new_ctx->assigned_links);
1319 	rcu_assign_pointer(link_conf->chanctx_conf, &new_ctx->conf);
1320 
1321 	if (sdata->vif.type == NL80211_IFTYPE_AP)
1322 		__ieee80211_link_copy_chanctx_to_vlans(link, false);
1323 
1324 	ieee80211_check_fast_xmit_iface(sdata);
1325 
1326 	if (ieee80211_chanctx_refcount(local, old_ctx) == 0)
1327 		ieee80211_free_chanctx(local, old_ctx);
1328 
1329 	ieee80211_recalc_chanctx_min_def(local, new_ctx, NULL);
1330 	ieee80211_recalc_smps_chanctx(local, new_ctx);
1331 	ieee80211_recalc_radar_chanctx(local, new_ctx);
1332 
1333 	if (changed)
1334 		ieee80211_link_info_change_notify(sdata, link, changed);
1335 
1336 out:
1337 	ieee80211_link_chanctx_reservation_complete(link);
1338 	return err;
1339 }
1340 
1341 static int
1342 ieee80211_link_use_reserved_assign(struct ieee80211_link_data *link)
1343 {
1344 	struct ieee80211_sub_if_data *sdata = link->sdata;
1345 	struct ieee80211_local *local = sdata->local;
1346 	struct ieee80211_chanctx *old_ctx, *new_ctx;
1347 	const struct cfg80211_chan_def *chandef;
1348 	int err;
1349 
1350 	old_ctx = ieee80211_link_get_chanctx(link);
1351 	new_ctx = link->reserved_chanctx;
1352 
1353 	if (WARN_ON(!link->reserved_ready))
1354 		return -EINVAL;
1355 
1356 	if (WARN_ON(old_ctx))
1357 		return -EINVAL;
1358 
1359 	if (WARN_ON(!new_ctx))
1360 		return -EINVAL;
1361 
1362 	if (WARN_ON(new_ctx->replace_state ==
1363 		    IEEE80211_CHANCTX_REPLACES_OTHER))
1364 		return -EINVAL;
1365 
1366 	chandef = ieee80211_chanctx_non_reserved_chandef(local, new_ctx,
1367 				&link->reserved_chandef);
1368 	if (WARN_ON(!chandef))
1369 		return -EINVAL;
1370 
1371 	ieee80211_change_chanctx(local, new_ctx, new_ctx, chandef);
1372 
1373 	list_del(&link->reserved_chanctx_list);
1374 	link->reserved_chanctx = NULL;
1375 
1376 	err = ieee80211_assign_link_chanctx(link, new_ctx);
1377 	if (err) {
1378 		if (ieee80211_chanctx_refcount(local, new_ctx) == 0)
1379 			ieee80211_free_chanctx(local, new_ctx);
1380 
1381 		goto out;
1382 	}
1383 
1384 out:
1385 	ieee80211_link_chanctx_reservation_complete(link);
1386 	return err;
1387 }
1388 
1389 static bool
1390 ieee80211_link_has_in_place_reservation(struct ieee80211_link_data *link)
1391 {
1392 	struct ieee80211_sub_if_data *sdata = link->sdata;
1393 	struct ieee80211_chanctx *old_ctx, *new_ctx;
1394 
1395 	lockdep_assert_wiphy(sdata->local->hw.wiphy);
1396 
1397 	new_ctx = link->reserved_chanctx;
1398 	old_ctx = ieee80211_link_get_chanctx(link);
1399 
1400 	if (!old_ctx)
1401 		return false;
1402 
1403 	if (WARN_ON(!new_ctx))
1404 		return false;
1405 
1406 	if (old_ctx->replace_state != IEEE80211_CHANCTX_WILL_BE_REPLACED)
1407 		return false;
1408 
1409 	if (new_ctx->replace_state != IEEE80211_CHANCTX_REPLACES_OTHER)
1410 		return false;
1411 
1412 	return true;
1413 }
1414 
1415 static int ieee80211_chsw_switch_hwconf(struct ieee80211_local *local,
1416 					struct ieee80211_chanctx *new_ctx)
1417 {
1418 	const struct cfg80211_chan_def *chandef;
1419 
1420 	lockdep_assert_wiphy(local->hw.wiphy);
1421 
1422 	chandef = ieee80211_chanctx_reserved_chandef(local, new_ctx, NULL);
1423 	if (WARN_ON(!chandef))
1424 		return -EINVAL;
1425 
1426 	local->hw.conf.radar_enabled = new_ctx->conf.radar_enabled;
1427 	local->_oper_chandef = *chandef;
1428 	ieee80211_hw_config(local, 0);
1429 
1430 	return 0;
1431 }
1432 
1433 static int ieee80211_chsw_switch_vifs(struct ieee80211_local *local,
1434 				      int n_vifs)
1435 {
1436 	struct ieee80211_vif_chanctx_switch *vif_chsw;
1437 	struct ieee80211_link_data *link;
1438 	struct ieee80211_chanctx *ctx, *old_ctx;
1439 	int i, err;
1440 
1441 	lockdep_assert_wiphy(local->hw.wiphy);
1442 
1443 	vif_chsw = kcalloc(n_vifs, sizeof(vif_chsw[0]), GFP_KERNEL);
1444 	if (!vif_chsw)
1445 		return -ENOMEM;
1446 
1447 	i = 0;
1448 	list_for_each_entry(ctx, &local->chanctx_list, list) {
1449 		if (ctx->replace_state != IEEE80211_CHANCTX_REPLACES_OTHER)
1450 			continue;
1451 
1452 		if (WARN_ON(!ctx->replace_ctx)) {
1453 			err = -EINVAL;
1454 			goto out;
1455 		}
1456 
1457 		list_for_each_entry(link, &ctx->reserved_links,
1458 				    reserved_chanctx_list) {
1459 			if (!ieee80211_link_has_in_place_reservation(link))
1460 				continue;
1461 
1462 			old_ctx = ieee80211_link_get_chanctx(link);
1463 			vif_chsw[i].vif = &link->sdata->vif;
1464 			vif_chsw[i].old_ctx = &old_ctx->conf;
1465 			vif_chsw[i].new_ctx = &ctx->conf;
1466 			vif_chsw[i].link_conf = link->conf;
1467 
1468 			i++;
1469 		}
1470 	}
1471 
1472 	err = drv_switch_vif_chanctx(local, vif_chsw, n_vifs,
1473 				     CHANCTX_SWMODE_SWAP_CONTEXTS);
1474 
1475 out:
1476 	kfree(vif_chsw);
1477 	return err;
1478 }
1479 
1480 static int ieee80211_chsw_switch_ctxs(struct ieee80211_local *local)
1481 {
1482 	struct ieee80211_chanctx *ctx;
1483 	int err;
1484 
1485 	lockdep_assert_wiphy(local->hw.wiphy);
1486 
1487 	list_for_each_entry(ctx, &local->chanctx_list, list) {
1488 		if (ctx->replace_state != IEEE80211_CHANCTX_REPLACES_OTHER)
1489 			continue;
1490 
1491 		if (!list_empty(&ctx->replace_ctx->assigned_links))
1492 			continue;
1493 
1494 		ieee80211_del_chanctx(local, ctx->replace_ctx);
1495 		err = ieee80211_add_chanctx(local, ctx);
1496 		if (err)
1497 			goto err;
1498 	}
1499 
1500 	return 0;
1501 
1502 err:
1503 	WARN_ON(ieee80211_add_chanctx(local, ctx));
1504 	list_for_each_entry_continue_reverse(ctx, &local->chanctx_list, list) {
1505 		if (ctx->replace_state != IEEE80211_CHANCTX_REPLACES_OTHER)
1506 			continue;
1507 
1508 		if (!list_empty(&ctx->replace_ctx->assigned_links))
1509 			continue;
1510 
1511 		ieee80211_del_chanctx(local, ctx);
1512 		WARN_ON(ieee80211_add_chanctx(local, ctx->replace_ctx));
1513 	}
1514 
1515 	return err;
1516 }
1517 
1518 static int ieee80211_vif_use_reserved_switch(struct ieee80211_local *local)
1519 {
1520 	struct ieee80211_chanctx *ctx, *ctx_tmp, *old_ctx;
1521 	struct ieee80211_chanctx *new_ctx = NULL;
1522 	int err, n_assigned, n_reserved, n_ready;
1523 	int n_ctx = 0, n_vifs_switch = 0, n_vifs_assign = 0, n_vifs_ctxless = 0;
1524 
1525 	lockdep_assert_wiphy(local->hw.wiphy);
1526 
1527 	/*
1528 	 * If there are 2 independent pairs of channel contexts performing
1529 	 * cross-switch of their vifs this code will still wait until both are
1530 	 * ready even though it could be possible to switch one before the
1531 	 * other is ready.
1532 	 *
1533 	 * For practical reasons and code simplicity just do a single huge
1534 	 * switch.
1535 	 */
1536 
1537 	/*
1538 	 * Verify if the reservation is still feasible.
1539 	 *  - if it's not then disconnect
1540 	 *  - if it is but not all vifs necessary are ready then defer
1541 	 */
1542 
1543 	list_for_each_entry(ctx, &local->chanctx_list, list) {
1544 		struct ieee80211_link_data *link;
1545 
1546 		if (ctx->replace_state != IEEE80211_CHANCTX_REPLACES_OTHER)
1547 			continue;
1548 
1549 		if (WARN_ON(!ctx->replace_ctx)) {
1550 			err = -EINVAL;
1551 			goto err;
1552 		}
1553 
1554 		if (!local->use_chanctx)
1555 			new_ctx = ctx;
1556 
1557 		n_ctx++;
1558 
1559 		n_assigned = 0;
1560 		n_reserved = 0;
1561 		n_ready = 0;
1562 
1563 		list_for_each_entry(link, &ctx->replace_ctx->assigned_links,
1564 				    assigned_chanctx_list) {
1565 			n_assigned++;
1566 			if (link->reserved_chanctx) {
1567 				n_reserved++;
1568 				if (link->reserved_ready)
1569 					n_ready++;
1570 			}
1571 		}
1572 
1573 		if (n_assigned != n_reserved) {
1574 			if (n_ready == n_reserved) {
1575 				wiphy_info(local->hw.wiphy,
1576 					   "channel context reservation cannot be finalized because some interfaces aren't switching\n");
1577 				err = -EBUSY;
1578 				goto err;
1579 			}
1580 
1581 			return -EAGAIN;
1582 		}
1583 
1584 		ctx->conf.radar_enabled = false;
1585 		list_for_each_entry(link, &ctx->reserved_links,
1586 				    reserved_chanctx_list) {
1587 			if (ieee80211_link_has_in_place_reservation(link) &&
1588 			    !link->reserved_ready)
1589 				return -EAGAIN;
1590 
1591 			old_ctx = ieee80211_link_get_chanctx(link);
1592 			if (old_ctx) {
1593 				if (old_ctx->replace_state ==
1594 				    IEEE80211_CHANCTX_WILL_BE_REPLACED)
1595 					n_vifs_switch++;
1596 				else
1597 					n_vifs_assign++;
1598 			} else {
1599 				n_vifs_ctxless++;
1600 			}
1601 
1602 			if (link->reserved_radar_required)
1603 				ctx->conf.radar_enabled = true;
1604 		}
1605 	}
1606 
1607 	if (WARN_ON(n_ctx == 0) ||
1608 	    WARN_ON(n_vifs_switch == 0 &&
1609 		    n_vifs_assign == 0 &&
1610 		    n_vifs_ctxless == 0) ||
1611 	    WARN_ON(n_ctx > 1 && !local->use_chanctx) ||
1612 	    WARN_ON(!new_ctx && !local->use_chanctx)) {
1613 		err = -EINVAL;
1614 		goto err;
1615 	}
1616 
1617 	/*
1618 	 * All necessary vifs are ready. Perform the switch now depending on
1619 	 * reservations and driver capabilities.
1620 	 */
1621 
1622 	if (local->use_chanctx) {
1623 		if (n_vifs_switch > 0) {
1624 			err = ieee80211_chsw_switch_vifs(local, n_vifs_switch);
1625 			if (err)
1626 				goto err;
1627 		}
1628 
1629 		if (n_vifs_assign > 0 || n_vifs_ctxless > 0) {
1630 			err = ieee80211_chsw_switch_ctxs(local);
1631 			if (err)
1632 				goto err;
1633 		}
1634 	} else {
1635 		err = ieee80211_chsw_switch_hwconf(local, new_ctx);
1636 		if (err)
1637 			goto err;
1638 	}
1639 
1640 	/*
1641 	 * Update all structures, values and pointers to point to new channel
1642 	 * context(s).
1643 	 */
1644 	list_for_each_entry(ctx, &local->chanctx_list, list) {
1645 		struct ieee80211_link_data *link, *link_tmp;
1646 
1647 		if (ctx->replace_state != IEEE80211_CHANCTX_REPLACES_OTHER)
1648 			continue;
1649 
1650 		if (WARN_ON(!ctx->replace_ctx)) {
1651 			err = -EINVAL;
1652 			goto err;
1653 		}
1654 
1655 		list_for_each_entry(link, &ctx->reserved_links,
1656 				    reserved_chanctx_list) {
1657 			struct ieee80211_sub_if_data *sdata = link->sdata;
1658 			struct ieee80211_bss_conf *link_conf = link->conf;
1659 			u64 changed = 0;
1660 
1661 			if (!ieee80211_link_has_in_place_reservation(link))
1662 				continue;
1663 
1664 			rcu_assign_pointer(link_conf->chanctx_conf,
1665 					   &ctx->conf);
1666 
1667 			if (sdata->vif.type == NL80211_IFTYPE_AP)
1668 				__ieee80211_link_copy_chanctx_to_vlans(link,
1669 								       false);
1670 
1671 			ieee80211_check_fast_xmit_iface(sdata);
1672 
1673 			link->radar_required = link->reserved_radar_required;
1674 
1675 			if (link_conf->chandef.width != link->reserved_chandef.width)
1676 				changed = BSS_CHANGED_BANDWIDTH;
1677 
1678 			ieee80211_link_update_chandef(link, &link->reserved_chandef);
1679 			if (changed)
1680 				ieee80211_link_info_change_notify(sdata,
1681 								  link,
1682 								  changed);
1683 
1684 			ieee80211_recalc_txpower(sdata, false);
1685 		}
1686 
1687 		ieee80211_recalc_chanctx_chantype(local, ctx);
1688 		ieee80211_recalc_smps_chanctx(local, ctx);
1689 		ieee80211_recalc_radar_chanctx(local, ctx);
1690 		ieee80211_recalc_chanctx_min_def(local, ctx, NULL);
1691 
1692 		list_for_each_entry_safe(link, link_tmp, &ctx->reserved_links,
1693 					 reserved_chanctx_list) {
1694 			if (ieee80211_link_get_chanctx(link) != ctx)
1695 				continue;
1696 
1697 			list_del(&link->reserved_chanctx_list);
1698 			list_move(&link->assigned_chanctx_list,
1699 				  &ctx->assigned_links);
1700 			link->reserved_chanctx = NULL;
1701 
1702 			ieee80211_link_chanctx_reservation_complete(link);
1703 		}
1704 
1705 		/*
1706 		 * This context might have been a dependency for an already
1707 		 * ready re-assign reservation interface that was deferred. Do
1708 		 * not propagate error to the caller though. The in-place
1709 		 * reservation for originally requested interface has already
1710 		 * succeeded at this point.
1711 		 */
1712 		list_for_each_entry_safe(link, link_tmp, &ctx->reserved_links,
1713 					 reserved_chanctx_list) {
1714 			if (WARN_ON(ieee80211_link_has_in_place_reservation(link)))
1715 				continue;
1716 
1717 			if (WARN_ON(link->reserved_chanctx != ctx))
1718 				continue;
1719 
1720 			if (!link->reserved_ready)
1721 				continue;
1722 
1723 			if (ieee80211_link_get_chanctx(link))
1724 				err = ieee80211_link_use_reserved_reassign(link);
1725 			else
1726 				err = ieee80211_link_use_reserved_assign(link);
1727 
1728 			if (err) {
1729 				link_info(link,
1730 					  "failed to finalize (re-)assign reservation (err=%d)\n",
1731 					  err);
1732 				ieee80211_link_unreserve_chanctx(link);
1733 				cfg80211_stop_iface(local->hw.wiphy,
1734 						    &link->sdata->wdev,
1735 						    GFP_KERNEL);
1736 			}
1737 		}
1738 	}
1739 
1740 	/*
1741 	 * Finally free old contexts
1742 	 */
1743 
1744 	list_for_each_entry_safe(ctx, ctx_tmp, &local->chanctx_list, list) {
1745 		if (ctx->replace_state != IEEE80211_CHANCTX_WILL_BE_REPLACED)
1746 			continue;
1747 
1748 		ctx->replace_ctx->replace_ctx = NULL;
1749 		ctx->replace_ctx->replace_state =
1750 				IEEE80211_CHANCTX_REPLACE_NONE;
1751 
1752 		list_del_rcu(&ctx->list);
1753 		kfree_rcu(ctx, rcu_head);
1754 	}
1755 
1756 	return 0;
1757 
1758 err:
1759 	list_for_each_entry(ctx, &local->chanctx_list, list) {
1760 		struct ieee80211_link_data *link, *link_tmp;
1761 
1762 		if (ctx->replace_state != IEEE80211_CHANCTX_REPLACES_OTHER)
1763 			continue;
1764 
1765 		list_for_each_entry_safe(link, link_tmp, &ctx->reserved_links,
1766 					 reserved_chanctx_list) {
1767 			ieee80211_link_unreserve_chanctx(link);
1768 			ieee80211_link_chanctx_reservation_complete(link);
1769 		}
1770 	}
1771 
1772 	return err;
1773 }
1774 
1775 static void __ieee80211_link_release_channel(struct ieee80211_link_data *link)
1776 {
1777 	struct ieee80211_sub_if_data *sdata = link->sdata;
1778 	struct ieee80211_bss_conf *link_conf = link->conf;
1779 	struct ieee80211_local *local = sdata->local;
1780 	struct ieee80211_chanctx_conf *conf;
1781 	struct ieee80211_chanctx *ctx;
1782 	bool use_reserved_switch = false;
1783 
1784 	lockdep_assert_wiphy(local->hw.wiphy);
1785 
1786 	conf = rcu_dereference_protected(link_conf->chanctx_conf,
1787 					 lockdep_is_held(&local->hw.wiphy->mtx));
1788 	if (!conf)
1789 		return;
1790 
1791 	ctx = container_of(conf, struct ieee80211_chanctx, conf);
1792 
1793 	if (link->reserved_chanctx) {
1794 		if (link->reserved_chanctx->replace_state == IEEE80211_CHANCTX_REPLACES_OTHER &&
1795 		    ieee80211_chanctx_num_reserved(local, link->reserved_chanctx) > 1)
1796 			use_reserved_switch = true;
1797 
1798 		ieee80211_link_unreserve_chanctx(link);
1799 	}
1800 
1801 	ieee80211_assign_link_chanctx(link, NULL);
1802 	if (ieee80211_chanctx_refcount(local, ctx) == 0)
1803 		ieee80211_free_chanctx(local, ctx);
1804 
1805 	link->radar_required = false;
1806 
1807 	/* Unreserving may ready an in-place reservation. */
1808 	if (use_reserved_switch)
1809 		ieee80211_vif_use_reserved_switch(local);
1810 }
1811 
1812 int ieee80211_link_use_channel(struct ieee80211_link_data *link,
1813 			       const struct cfg80211_chan_def *chandef,
1814 			       enum ieee80211_chanctx_mode mode)
1815 {
1816 	struct ieee80211_sub_if_data *sdata = link->sdata;
1817 	struct ieee80211_local *local = sdata->local;
1818 	struct ieee80211_chanctx *ctx;
1819 	u8 radar_detect_width = 0;
1820 	int ret;
1821 
1822 	lockdep_assert_wiphy(local->hw.wiphy);
1823 
1824 	if (sdata->vif.active_links &&
1825 	    !(sdata->vif.active_links & BIT(link->link_id))) {
1826 		ieee80211_link_update_chandef(link, chandef);
1827 		return 0;
1828 	}
1829 
1830 	ret = cfg80211_chandef_dfs_required(local->hw.wiphy,
1831 					    chandef,
1832 					    sdata->wdev.iftype);
1833 	if (ret < 0)
1834 		goto out;
1835 	if (ret > 0)
1836 		radar_detect_width = BIT(chandef->width);
1837 
1838 	link->radar_required = ret;
1839 
1840 	ret = ieee80211_check_combinations(sdata, chandef, mode,
1841 					   radar_detect_width);
1842 	if (ret < 0)
1843 		goto out;
1844 
1845 	__ieee80211_link_release_channel(link);
1846 
1847 	ctx = ieee80211_find_chanctx(local, chandef, mode);
1848 	if (!ctx)
1849 		ctx = ieee80211_new_chanctx(local, chandef, mode);
1850 	if (IS_ERR(ctx)) {
1851 		ret = PTR_ERR(ctx);
1852 		goto out;
1853 	}
1854 
1855 	ieee80211_link_update_chandef(link, chandef);
1856 
1857 	ret = ieee80211_assign_link_chanctx(link, ctx);
1858 	if (ret) {
1859 		/* if assign fails refcount stays the same */
1860 		if (ieee80211_chanctx_refcount(local, ctx) == 0)
1861 			ieee80211_free_chanctx(local, ctx);
1862 		goto out;
1863 	}
1864 
1865 	ieee80211_recalc_smps_chanctx(local, ctx);
1866 	ieee80211_recalc_radar_chanctx(local, ctx);
1867  out:
1868 	if (ret)
1869 		link->radar_required = false;
1870 
1871 	return ret;
1872 }
1873 
1874 int ieee80211_link_use_reserved_context(struct ieee80211_link_data *link)
1875 {
1876 	struct ieee80211_sub_if_data *sdata = link->sdata;
1877 	struct ieee80211_local *local = sdata->local;
1878 	struct ieee80211_chanctx *new_ctx;
1879 	struct ieee80211_chanctx *old_ctx;
1880 	int err;
1881 
1882 	lockdep_assert_wiphy(local->hw.wiphy);
1883 
1884 	new_ctx = link->reserved_chanctx;
1885 	old_ctx = ieee80211_link_get_chanctx(link);
1886 
1887 	if (WARN_ON(!new_ctx))
1888 		return -EINVAL;
1889 
1890 	if (WARN_ON(new_ctx->replace_state ==
1891 		    IEEE80211_CHANCTX_WILL_BE_REPLACED))
1892 		return -EINVAL;
1893 
1894 	if (WARN_ON(link->reserved_ready))
1895 		return -EINVAL;
1896 
1897 	link->reserved_ready = true;
1898 
1899 	if (new_ctx->replace_state == IEEE80211_CHANCTX_REPLACE_NONE) {
1900 		if (old_ctx)
1901 			return ieee80211_link_use_reserved_reassign(link);
1902 
1903 		return ieee80211_link_use_reserved_assign(link);
1904 	}
1905 
1906 	/*
1907 	 * In-place reservation may need to be finalized now either if:
1908 	 *  a) sdata is taking part in the swapping itself and is the last one
1909 	 *  b) sdata has switched with a re-assign reservation to an existing
1910 	 *     context readying in-place switching of old_ctx
1911 	 *
1912 	 * In case of (b) do not propagate the error up because the requested
1913 	 * sdata already switched successfully. Just spill an extra warning.
1914 	 * The ieee80211_vif_use_reserved_switch() already stops all necessary
1915 	 * interfaces upon failure.
1916 	 */
1917 	if ((old_ctx &&
1918 	     old_ctx->replace_state == IEEE80211_CHANCTX_WILL_BE_REPLACED) ||
1919 	    new_ctx->replace_state == IEEE80211_CHANCTX_REPLACES_OTHER) {
1920 		err = ieee80211_vif_use_reserved_switch(local);
1921 		if (err && err != -EAGAIN) {
1922 			if (new_ctx->replace_state ==
1923 			    IEEE80211_CHANCTX_REPLACES_OTHER)
1924 				return err;
1925 
1926 			wiphy_info(local->hw.wiphy,
1927 				   "depending in-place reservation failed (err=%d)\n",
1928 				   err);
1929 		}
1930 	}
1931 
1932 	return 0;
1933 }
1934 
1935 int ieee80211_link_change_bandwidth(struct ieee80211_link_data *link,
1936 				    const struct cfg80211_chan_def *chandef,
1937 				    u64 *changed)
1938 {
1939 	struct ieee80211_sub_if_data *sdata = link->sdata;
1940 	struct ieee80211_bss_conf *link_conf = link->conf;
1941 	struct ieee80211_local *local = sdata->local;
1942 	struct ieee80211_chanctx_conf *conf;
1943 	struct ieee80211_chanctx *ctx;
1944 	const struct cfg80211_chan_def *compat;
1945 
1946 	lockdep_assert_wiphy(local->hw.wiphy);
1947 
1948 	if (!cfg80211_chandef_usable(sdata->local->hw.wiphy, chandef,
1949 				     IEEE80211_CHAN_DISABLED))
1950 		return -EINVAL;
1951 
1952 	if (cfg80211_chandef_identical(chandef, &link_conf->chandef))
1953 		return 0;
1954 
1955 	if (chandef->width == NL80211_CHAN_WIDTH_20_NOHT ||
1956 	    link_conf->chandef.width == NL80211_CHAN_WIDTH_20_NOHT)
1957 		return -EINVAL;
1958 
1959 	conf = rcu_dereference_protected(link_conf->chanctx_conf,
1960 					 lockdep_is_held(&local->hw.wiphy->mtx));
1961 	if (!conf)
1962 		return -EINVAL;
1963 
1964 	ctx = container_of(conf, struct ieee80211_chanctx, conf);
1965 
1966 	compat = cfg80211_chandef_compatible(&conf->def, chandef);
1967 	if (!compat)
1968 		return -EINVAL;
1969 
1970 	switch (ctx->replace_state) {
1971 	case IEEE80211_CHANCTX_REPLACE_NONE:
1972 		if (!ieee80211_chanctx_reserved_chandef(local, ctx, compat))
1973 			return -EBUSY;
1974 		break;
1975 	case IEEE80211_CHANCTX_WILL_BE_REPLACED:
1976 		/* TODO: Perhaps the bandwidth change could be treated as a
1977 		 * reservation itself? */
1978 		return -EBUSY;
1979 	case IEEE80211_CHANCTX_REPLACES_OTHER:
1980 		/* channel context that is going to replace another channel
1981 		 * context doesn't really exist and shouldn't be assigned
1982 		 * anywhere yet */
1983 		WARN_ON(1);
1984 		break;
1985 	}
1986 
1987 	ieee80211_link_update_chandef(link, chandef);
1988 
1989 	ieee80211_recalc_chanctx_chantype(local, ctx);
1990 
1991 	*changed |= BSS_CHANGED_BANDWIDTH;
1992 	return 0;
1993 }
1994 
1995 void ieee80211_link_release_channel(struct ieee80211_link_data *link)
1996 {
1997 	struct ieee80211_sub_if_data *sdata = link->sdata;
1998 
1999 	lockdep_assert_wiphy(sdata->local->hw.wiphy);
2000 
2001 	if (rcu_access_pointer(link->conf->chanctx_conf))
2002 		__ieee80211_link_release_channel(link);
2003 }
2004 
2005 void ieee80211_link_vlan_copy_chanctx(struct ieee80211_link_data *link)
2006 {
2007 	struct ieee80211_sub_if_data *sdata = link->sdata;
2008 	unsigned int link_id = link->link_id;
2009 	struct ieee80211_bss_conf *link_conf = link->conf;
2010 	struct ieee80211_bss_conf *ap_conf;
2011 	struct ieee80211_local *local = sdata->local;
2012 	struct ieee80211_sub_if_data *ap;
2013 	struct ieee80211_chanctx_conf *conf;
2014 
2015 	lockdep_assert_wiphy(local->hw.wiphy);
2016 
2017 	if (WARN_ON(sdata->vif.type != NL80211_IFTYPE_AP_VLAN || !sdata->bss))
2018 		return;
2019 
2020 	ap = container_of(sdata->bss, struct ieee80211_sub_if_data, u.ap);
2021 
2022 	rcu_read_lock();
2023 	ap_conf = rcu_dereference(ap->vif.link_conf[link_id]);
2024 	conf = rcu_dereference_protected(ap_conf->chanctx_conf,
2025 					 lockdep_is_held(&local->hw.wiphy->mtx));
2026 	rcu_assign_pointer(link_conf->chanctx_conf, conf);
2027 	rcu_read_unlock();
2028 }
2029 
2030 void ieee80211_iter_chan_contexts_atomic(
2031 	struct ieee80211_hw *hw,
2032 	void (*iter)(struct ieee80211_hw *hw,
2033 		     struct ieee80211_chanctx_conf *chanctx_conf,
2034 		     void *data),
2035 	void *iter_data)
2036 {
2037 	struct ieee80211_local *local = hw_to_local(hw);
2038 	struct ieee80211_chanctx *ctx;
2039 
2040 	rcu_read_lock();
2041 	list_for_each_entry_rcu(ctx, &local->chanctx_list, list)
2042 		if (ctx->driver_present)
2043 			iter(hw, &ctx->conf, iter_data);
2044 	rcu_read_unlock();
2045 }
2046 EXPORT_SYMBOL_GPL(ieee80211_iter_chan_contexts_atomic);
2047