xref: /openbmc/linux/net/mac80211/chan.c (revision 9b68f30b)
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_held(&local->chanctx_mtx);
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_held(&local->chanctx_mtx);
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_held(&local->chanctx_mtx);
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_held(&local->chanctx_mtx);
66 	return ieee80211_num_chanctx(local) < ieee80211_max_num_channels(local);
67 }
68 
69 static struct ieee80211_chanctx *
70 ieee80211_link_get_chanctx(struct ieee80211_link_data *link)
71 {
72 	struct ieee80211_local *local __maybe_unused = link->sdata->local;
73 	struct ieee80211_chanctx_conf *conf;
74 
75 	conf = rcu_dereference_protected(link->conf->chanctx_conf,
76 					 lockdep_is_held(&local->chanctx_mtx));
77 	if (!conf)
78 		return NULL;
79 
80 	return container_of(conf, struct ieee80211_chanctx, conf);
81 }
82 
83 static const struct cfg80211_chan_def *
84 ieee80211_chanctx_reserved_chandef(struct ieee80211_local *local,
85 				   struct ieee80211_chanctx *ctx,
86 				   const struct cfg80211_chan_def *compat)
87 {
88 	struct ieee80211_link_data *link;
89 
90 	lockdep_assert_held(&local->chanctx_mtx);
91 
92 	list_for_each_entry(link, &ctx->reserved_links,
93 			    reserved_chanctx_list) {
94 		if (!compat)
95 			compat = &link->reserved_chandef;
96 
97 		compat = cfg80211_chandef_compatible(&link->reserved_chandef,
98 						     compat);
99 		if (!compat)
100 			break;
101 	}
102 
103 	return compat;
104 }
105 
106 static const struct cfg80211_chan_def *
107 ieee80211_chanctx_non_reserved_chandef(struct ieee80211_local *local,
108 				       struct ieee80211_chanctx *ctx,
109 				       const struct cfg80211_chan_def *compat)
110 {
111 	struct ieee80211_link_data *link;
112 
113 	lockdep_assert_held(&local->chanctx_mtx);
114 
115 	list_for_each_entry(link, &ctx->assigned_links,
116 			    assigned_chanctx_list) {
117 		struct ieee80211_bss_conf *link_conf = link->conf;
118 
119 		if (link->reserved_chanctx)
120 			continue;
121 
122 		if (!compat)
123 			compat = &link_conf->chandef;
124 
125 		compat = cfg80211_chandef_compatible(
126 				&link_conf->chandef, compat);
127 		if (!compat)
128 			break;
129 	}
130 
131 	return compat;
132 }
133 
134 static const struct cfg80211_chan_def *
135 ieee80211_chanctx_combined_chandef(struct ieee80211_local *local,
136 				   struct ieee80211_chanctx *ctx,
137 				   const struct cfg80211_chan_def *compat)
138 {
139 	lockdep_assert_held(&local->chanctx_mtx);
140 
141 	compat = ieee80211_chanctx_reserved_chandef(local, ctx, compat);
142 	if (!compat)
143 		return NULL;
144 
145 	compat = ieee80211_chanctx_non_reserved_chandef(local, ctx, compat);
146 	if (!compat)
147 		return NULL;
148 
149 	return compat;
150 }
151 
152 static bool
153 ieee80211_chanctx_can_reserve_chandef(struct ieee80211_local *local,
154 				      struct ieee80211_chanctx *ctx,
155 				      const struct cfg80211_chan_def *def)
156 {
157 	lockdep_assert_held(&local->chanctx_mtx);
158 
159 	if (ieee80211_chanctx_combined_chandef(local, ctx, def))
160 		return true;
161 
162 	if (!list_empty(&ctx->reserved_links) &&
163 	    ieee80211_chanctx_reserved_chandef(local, ctx, def))
164 		return true;
165 
166 	return false;
167 }
168 
169 static struct ieee80211_chanctx *
170 ieee80211_find_reservation_chanctx(struct ieee80211_local *local,
171 				   const struct cfg80211_chan_def *chandef,
172 				   enum ieee80211_chanctx_mode mode)
173 {
174 	struct ieee80211_chanctx *ctx;
175 
176 	lockdep_assert_held(&local->chanctx_mtx);
177 
178 	if (mode == IEEE80211_CHANCTX_EXCLUSIVE)
179 		return NULL;
180 
181 	list_for_each_entry(ctx, &local->chanctx_list, list) {
182 		if (ctx->replace_state == IEEE80211_CHANCTX_WILL_BE_REPLACED)
183 			continue;
184 
185 		if (ctx->mode == IEEE80211_CHANCTX_EXCLUSIVE)
186 			continue;
187 
188 		if (!ieee80211_chanctx_can_reserve_chandef(local, ctx,
189 							   chandef))
190 			continue;
191 
192 		return ctx;
193 	}
194 
195 	return NULL;
196 }
197 
198 static enum nl80211_chan_width ieee80211_get_sta_bw(struct sta_info *sta,
199 						    unsigned int link_id)
200 {
201 	enum ieee80211_sta_rx_bandwidth width;
202 	struct link_sta_info *link_sta;
203 
204 	link_sta = rcu_dereference(sta->link[link_id]);
205 
206 	/* no effect if this STA has no presence on this link */
207 	if (!link_sta)
208 		return NL80211_CHAN_WIDTH_20_NOHT;
209 
210 	width = ieee80211_sta_cap_rx_bw(link_sta);
211 
212 	switch (width) {
213 	case IEEE80211_STA_RX_BW_20:
214 		if (link_sta->pub->ht_cap.ht_supported)
215 			return NL80211_CHAN_WIDTH_20;
216 		else
217 			return NL80211_CHAN_WIDTH_20_NOHT;
218 	case IEEE80211_STA_RX_BW_40:
219 		return NL80211_CHAN_WIDTH_40;
220 	case IEEE80211_STA_RX_BW_80:
221 		return NL80211_CHAN_WIDTH_80;
222 	case IEEE80211_STA_RX_BW_160:
223 		/*
224 		 * This applied for both 160 and 80+80. since we use
225 		 * the returned value to consider degradation of
226 		 * ctx->conf.min_def, we have to make sure to take
227 		 * the bigger one (NL80211_CHAN_WIDTH_160).
228 		 * Otherwise we might try degrading even when not
229 		 * needed, as the max required sta_bw returned (80+80)
230 		 * might be smaller than the configured bw (160).
231 		 */
232 		return NL80211_CHAN_WIDTH_160;
233 	case IEEE80211_STA_RX_BW_320:
234 		return NL80211_CHAN_WIDTH_320;
235 	default:
236 		WARN_ON(1);
237 		return NL80211_CHAN_WIDTH_20;
238 	}
239 }
240 
241 static enum nl80211_chan_width
242 ieee80211_get_max_required_bw(struct ieee80211_sub_if_data *sdata,
243 			      unsigned int link_id)
244 {
245 	enum nl80211_chan_width max_bw = NL80211_CHAN_WIDTH_20_NOHT;
246 	struct sta_info *sta;
247 
248 	list_for_each_entry_rcu(sta, &sdata->local->sta_list, list) {
249 		if (sdata != sta->sdata &&
250 		    !(sta->sdata->bss && sta->sdata->bss == sdata->bss))
251 			continue;
252 
253 		max_bw = max(max_bw, ieee80211_get_sta_bw(sta, link_id));
254 	}
255 
256 	return max_bw;
257 }
258 
259 static enum nl80211_chan_width
260 ieee80211_get_chanctx_vif_max_required_bw(struct ieee80211_sub_if_data *sdata,
261 					  struct ieee80211_chanctx *ctx,
262 					  struct ieee80211_link_data *rsvd_for)
263 {
264 	enum nl80211_chan_width max_bw = NL80211_CHAN_WIDTH_20_NOHT;
265 	struct ieee80211_vif *vif = &sdata->vif;
266 	int link_id;
267 
268 	rcu_read_lock();
269 	for (link_id = 0; link_id < ARRAY_SIZE(sdata->link); link_id++) {
270 		enum nl80211_chan_width width = NL80211_CHAN_WIDTH_20_NOHT;
271 		struct ieee80211_link_data *link =
272 			rcu_dereference(sdata->link[link_id]);
273 
274 		if (!link)
275 			continue;
276 
277 		if (link != rsvd_for &&
278 		    rcu_access_pointer(link->conf->chanctx_conf) != &ctx->conf)
279 			continue;
280 
281 		switch (vif->type) {
282 		case NL80211_IFTYPE_AP:
283 		case NL80211_IFTYPE_AP_VLAN:
284 			width = ieee80211_get_max_required_bw(sdata, link_id);
285 			break;
286 		case NL80211_IFTYPE_STATION:
287 			/*
288 			 * The ap's sta->bandwidth is not set yet at this
289 			 * point, so take the width from the chandef, but
290 			 * account also for TDLS peers
291 			 */
292 			width = max(link->conf->chandef.width,
293 				    ieee80211_get_max_required_bw(sdata, link_id));
294 			break;
295 		case NL80211_IFTYPE_P2P_DEVICE:
296 		case NL80211_IFTYPE_NAN:
297 			continue;
298 		case NL80211_IFTYPE_ADHOC:
299 		case NL80211_IFTYPE_MESH_POINT:
300 		case NL80211_IFTYPE_OCB:
301 			width = link->conf->chandef.width;
302 			break;
303 		case NL80211_IFTYPE_WDS:
304 		case NL80211_IFTYPE_UNSPECIFIED:
305 		case NUM_NL80211_IFTYPES:
306 		case NL80211_IFTYPE_MONITOR:
307 		case NL80211_IFTYPE_P2P_CLIENT:
308 		case NL80211_IFTYPE_P2P_GO:
309 			WARN_ON_ONCE(1);
310 		}
311 
312 		max_bw = max(max_bw, width);
313 	}
314 	rcu_read_unlock();
315 
316 	return max_bw;
317 }
318 
319 static enum nl80211_chan_width
320 ieee80211_get_chanctx_max_required_bw(struct ieee80211_local *local,
321 				      struct ieee80211_chanctx *ctx,
322 				      struct ieee80211_link_data *rsvd_for)
323 {
324 	struct ieee80211_sub_if_data *sdata;
325 	enum nl80211_chan_width max_bw = NL80211_CHAN_WIDTH_20_NOHT;
326 
327 	rcu_read_lock();
328 	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
329 		enum nl80211_chan_width width;
330 
331 		if (!ieee80211_sdata_running(sdata))
332 			continue;
333 
334 		width = ieee80211_get_chanctx_vif_max_required_bw(sdata, ctx,
335 								  rsvd_for);
336 
337 		max_bw = max(max_bw, width);
338 	}
339 
340 	/* use the configured bandwidth in case of monitor interface */
341 	sdata = rcu_dereference(local->monitor_sdata);
342 	if (sdata &&
343 	    rcu_access_pointer(sdata->vif.bss_conf.chanctx_conf) == &ctx->conf)
344 		max_bw = max(max_bw, ctx->conf.def.width);
345 
346 	rcu_read_unlock();
347 
348 	return max_bw;
349 }
350 
351 /*
352  * recalc the min required chan width of the channel context, which is
353  * the max of min required widths of all the interfaces bound to this
354  * channel context.
355  */
356 static u32
357 _ieee80211_recalc_chanctx_min_def(struct ieee80211_local *local,
358 				  struct ieee80211_chanctx *ctx,
359 				  struct ieee80211_link_data *rsvd_for)
360 {
361 	enum nl80211_chan_width max_bw;
362 	struct cfg80211_chan_def min_def;
363 
364 	lockdep_assert_held(&local->chanctx_mtx);
365 
366 	/* don't optimize non-20MHz based and radar_enabled confs */
367 	if (ctx->conf.def.width == NL80211_CHAN_WIDTH_5 ||
368 	    ctx->conf.def.width == NL80211_CHAN_WIDTH_10 ||
369 	    ctx->conf.def.width == NL80211_CHAN_WIDTH_1 ||
370 	    ctx->conf.def.width == NL80211_CHAN_WIDTH_2 ||
371 	    ctx->conf.def.width == NL80211_CHAN_WIDTH_4 ||
372 	    ctx->conf.def.width == NL80211_CHAN_WIDTH_8 ||
373 	    ctx->conf.def.width == NL80211_CHAN_WIDTH_16 ||
374 	    ctx->conf.radar_enabled) {
375 		ctx->conf.min_def = ctx->conf.def;
376 		return 0;
377 	}
378 
379 	max_bw = ieee80211_get_chanctx_max_required_bw(local, ctx, rsvd_for);
380 
381 	/* downgrade chandef up to max_bw */
382 	min_def = ctx->conf.def;
383 	while (min_def.width > max_bw)
384 		ieee80211_chandef_downgrade(&min_def);
385 
386 	if (cfg80211_chandef_identical(&ctx->conf.min_def, &min_def))
387 		return 0;
388 
389 	ctx->conf.min_def = min_def;
390 	if (!ctx->driver_present)
391 		return 0;
392 
393 	return IEEE80211_CHANCTX_CHANGE_MIN_WIDTH;
394 }
395 
396 /* calling this function is assuming that station vif is updated to
397  * lates changes by calling ieee80211_link_update_chandef
398  */
399 static void ieee80211_chan_bw_change(struct ieee80211_local *local,
400 				     struct ieee80211_chanctx *ctx,
401 				     bool narrowed)
402 {
403 	struct sta_info *sta;
404 	struct ieee80211_supported_band *sband =
405 		local->hw.wiphy->bands[ctx->conf.def.chan->band];
406 
407 	rcu_read_lock();
408 	list_for_each_entry_rcu(sta, &local->sta_list,
409 				list) {
410 		struct ieee80211_sub_if_data *sdata = sta->sdata;
411 		enum ieee80211_sta_rx_bandwidth new_sta_bw;
412 		unsigned int link_id;
413 
414 		if (!ieee80211_sdata_running(sta->sdata))
415 			continue;
416 
417 		for (link_id = 0; link_id < ARRAY_SIZE(sta->sdata->link); link_id++) {
418 			struct ieee80211_bss_conf *link_conf =
419 				rcu_dereference(sdata->vif.link_conf[link_id]);
420 			struct link_sta_info *link_sta;
421 
422 			if (!link_conf)
423 				continue;
424 
425 			if (rcu_access_pointer(link_conf->chanctx_conf) != &ctx->conf)
426 				continue;
427 
428 			link_sta = rcu_dereference(sta->link[link_id]);
429 			if (!link_sta)
430 				continue;
431 
432 			new_sta_bw = ieee80211_sta_cur_vht_bw(link_sta);
433 
434 			/* nothing change */
435 			if (new_sta_bw == link_sta->pub->bandwidth)
436 				continue;
437 
438 			/* vif changed to narrow BW and narrow BW for station wasn't
439 			 * requested or vise versa */
440 			if ((new_sta_bw < link_sta->pub->bandwidth) == !narrowed)
441 				continue;
442 
443 			link_sta->pub->bandwidth = new_sta_bw;
444 			rate_control_rate_update(local, sband, sta, link_id,
445 						 IEEE80211_RC_BW_CHANGED);
446 		}
447 	}
448 	rcu_read_unlock();
449 }
450 
451 /*
452  * recalc the min required chan width of the channel context, which is
453  * the max of min required widths of all the interfaces bound to this
454  * channel context.
455  */
456 void ieee80211_recalc_chanctx_min_def(struct ieee80211_local *local,
457 				      struct ieee80211_chanctx *ctx,
458 				      struct ieee80211_link_data *rsvd_for)
459 {
460 	u32 changed = _ieee80211_recalc_chanctx_min_def(local, ctx, rsvd_for);
461 
462 	if (!changed)
463 		return;
464 
465 	/* check is BW narrowed */
466 	ieee80211_chan_bw_change(local, ctx, true);
467 
468 	drv_change_chanctx(local, ctx, changed);
469 
470 	/* check is BW wider */
471 	ieee80211_chan_bw_change(local, ctx, false);
472 }
473 
474 static void _ieee80211_change_chanctx(struct ieee80211_local *local,
475 				      struct ieee80211_chanctx *ctx,
476 				      struct ieee80211_chanctx *old_ctx,
477 				      const struct cfg80211_chan_def *chandef,
478 				      struct ieee80211_link_data *rsvd_for)
479 {
480 	u32 changed;
481 
482 	/* expected to handle only 20/40/80/160/320 channel widths */
483 	switch (chandef->width) {
484 	case NL80211_CHAN_WIDTH_20_NOHT:
485 	case NL80211_CHAN_WIDTH_20:
486 	case NL80211_CHAN_WIDTH_40:
487 	case NL80211_CHAN_WIDTH_80:
488 	case NL80211_CHAN_WIDTH_80P80:
489 	case NL80211_CHAN_WIDTH_160:
490 	case NL80211_CHAN_WIDTH_320:
491 		break;
492 	default:
493 		WARN_ON(1);
494 	}
495 
496 	/* Check maybe BW narrowed - we do this _before_ calling recalc_chanctx_min_def
497 	 * due to maybe not returning from it, e.g in case new context was added
498 	 * first time with all parameters up to date.
499 	 */
500 	ieee80211_chan_bw_change(local, old_ctx, true);
501 
502 	if (cfg80211_chandef_identical(&ctx->conf.def, chandef)) {
503 		ieee80211_recalc_chanctx_min_def(local, ctx, rsvd_for);
504 		return;
505 	}
506 
507 	WARN_ON(!cfg80211_chandef_compatible(&ctx->conf.def, chandef));
508 
509 	ctx->conf.def = *chandef;
510 
511 	/* check if min chanctx also changed */
512 	changed = IEEE80211_CHANCTX_CHANGE_WIDTH |
513 		  _ieee80211_recalc_chanctx_min_def(local, ctx, rsvd_for);
514 	drv_change_chanctx(local, ctx, changed);
515 
516 	if (!local->use_chanctx) {
517 		local->_oper_chandef = *chandef;
518 		ieee80211_hw_config(local, 0);
519 	}
520 
521 	/* check is BW wider */
522 	ieee80211_chan_bw_change(local, old_ctx, false);
523 }
524 
525 static void ieee80211_change_chanctx(struct ieee80211_local *local,
526 				     struct ieee80211_chanctx *ctx,
527 				     struct ieee80211_chanctx *old_ctx,
528 				     const struct cfg80211_chan_def *chandef)
529 {
530 	_ieee80211_change_chanctx(local, ctx, old_ctx, chandef, NULL);
531 }
532 
533 static struct ieee80211_chanctx *
534 ieee80211_find_chanctx(struct ieee80211_local *local,
535 		       const struct cfg80211_chan_def *chandef,
536 		       enum ieee80211_chanctx_mode mode)
537 {
538 	struct ieee80211_chanctx *ctx;
539 
540 	lockdep_assert_held(&local->chanctx_mtx);
541 
542 	if (mode == IEEE80211_CHANCTX_EXCLUSIVE)
543 		return NULL;
544 
545 	list_for_each_entry(ctx, &local->chanctx_list, list) {
546 		const struct cfg80211_chan_def *compat;
547 
548 		if (ctx->replace_state != IEEE80211_CHANCTX_REPLACE_NONE)
549 			continue;
550 
551 		if (ctx->mode == IEEE80211_CHANCTX_EXCLUSIVE)
552 			continue;
553 
554 		compat = cfg80211_chandef_compatible(&ctx->conf.def, chandef);
555 		if (!compat)
556 			continue;
557 
558 		compat = ieee80211_chanctx_reserved_chandef(local, ctx,
559 							    compat);
560 		if (!compat)
561 			continue;
562 
563 		ieee80211_change_chanctx(local, ctx, ctx, compat);
564 
565 		return ctx;
566 	}
567 
568 	return NULL;
569 }
570 
571 bool ieee80211_is_radar_required(struct ieee80211_local *local)
572 {
573 	struct ieee80211_sub_if_data *sdata;
574 
575 	lockdep_assert_held(&local->mtx);
576 
577 	rcu_read_lock();
578 	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
579 		unsigned int link_id;
580 
581 		for (link_id = 0; link_id < ARRAY_SIZE(sdata->link); link_id++) {
582 			struct ieee80211_link_data *link;
583 
584 			link = rcu_dereference(sdata->link[link_id]);
585 
586 			if (link && link->radar_required) {
587 				rcu_read_unlock();
588 				return true;
589 			}
590 		}
591 	}
592 	rcu_read_unlock();
593 
594 	return false;
595 }
596 
597 static bool
598 ieee80211_chanctx_radar_required(struct ieee80211_local *local,
599 				 struct ieee80211_chanctx *ctx)
600 {
601 	struct ieee80211_chanctx_conf *conf = &ctx->conf;
602 	struct ieee80211_sub_if_data *sdata;
603 	bool required = false;
604 
605 	lockdep_assert_held(&local->chanctx_mtx);
606 	lockdep_assert_held(&local->mtx);
607 
608 	rcu_read_lock();
609 	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
610 		unsigned int link_id;
611 
612 		if (!ieee80211_sdata_running(sdata))
613 			continue;
614 		for (link_id = 0; link_id < ARRAY_SIZE(sdata->link); link_id++) {
615 			struct ieee80211_link_data *link;
616 
617 			link = rcu_dereference(sdata->link[link_id]);
618 			if (!link)
619 				continue;
620 
621 			if (rcu_access_pointer(link->conf->chanctx_conf) != conf)
622 				continue;
623 			if (!link->radar_required)
624 				continue;
625 			required = true;
626 			break;
627 		}
628 
629 		if (required)
630 			break;
631 	}
632 	rcu_read_unlock();
633 
634 	return required;
635 }
636 
637 static struct ieee80211_chanctx *
638 ieee80211_alloc_chanctx(struct ieee80211_local *local,
639 			const struct cfg80211_chan_def *chandef,
640 			enum ieee80211_chanctx_mode mode)
641 {
642 	struct ieee80211_chanctx *ctx;
643 
644 	lockdep_assert_held(&local->chanctx_mtx);
645 
646 	ctx = kzalloc(sizeof(*ctx) + local->hw.chanctx_data_size, GFP_KERNEL);
647 	if (!ctx)
648 		return NULL;
649 
650 	INIT_LIST_HEAD(&ctx->assigned_links);
651 	INIT_LIST_HEAD(&ctx->reserved_links);
652 	ctx->conf.def = *chandef;
653 	ctx->conf.rx_chains_static = 1;
654 	ctx->conf.rx_chains_dynamic = 1;
655 	ctx->mode = mode;
656 	ctx->conf.radar_enabled = false;
657 	_ieee80211_recalc_chanctx_min_def(local, ctx, NULL);
658 
659 	return ctx;
660 }
661 
662 static int ieee80211_add_chanctx(struct ieee80211_local *local,
663 				 struct ieee80211_chanctx *ctx)
664 {
665 	u32 changed;
666 	int err;
667 
668 	lockdep_assert_held(&local->mtx);
669 	lockdep_assert_held(&local->chanctx_mtx);
670 
671 	if (!local->use_chanctx)
672 		local->hw.conf.radar_enabled = ctx->conf.radar_enabled;
673 
674 	/* turn idle off *before* setting channel -- some drivers need that */
675 	changed = ieee80211_idle_off(local);
676 	if (changed)
677 		ieee80211_hw_config(local, changed);
678 
679 	if (!local->use_chanctx) {
680 		local->_oper_chandef = ctx->conf.def;
681 		ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
682 	} else {
683 		err = drv_add_chanctx(local, ctx);
684 		if (err) {
685 			ieee80211_recalc_idle(local);
686 			return err;
687 		}
688 	}
689 
690 	return 0;
691 }
692 
693 static struct ieee80211_chanctx *
694 ieee80211_new_chanctx(struct ieee80211_local *local,
695 		      const struct cfg80211_chan_def *chandef,
696 		      enum ieee80211_chanctx_mode mode)
697 {
698 	struct ieee80211_chanctx *ctx;
699 	int err;
700 
701 	lockdep_assert_held(&local->mtx);
702 	lockdep_assert_held(&local->chanctx_mtx);
703 
704 	ctx = ieee80211_alloc_chanctx(local, chandef, mode);
705 	if (!ctx)
706 		return ERR_PTR(-ENOMEM);
707 
708 	err = ieee80211_add_chanctx(local, ctx);
709 	if (err) {
710 		kfree(ctx);
711 		return ERR_PTR(err);
712 	}
713 
714 	list_add_rcu(&ctx->list, &local->chanctx_list);
715 	return ctx;
716 }
717 
718 static void ieee80211_del_chanctx(struct ieee80211_local *local,
719 				  struct ieee80211_chanctx *ctx)
720 {
721 	lockdep_assert_held(&local->chanctx_mtx);
722 
723 	if (!local->use_chanctx) {
724 		struct cfg80211_chan_def *chandef = &local->_oper_chandef;
725 		/* S1G doesn't have 20MHz, so get the correct width for the
726 		 * current channel.
727 		 */
728 		if (chandef->chan->band == NL80211_BAND_S1GHZ)
729 			chandef->width =
730 				ieee80211_s1g_channel_width(chandef->chan);
731 		else
732 			chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
733 		chandef->center_freq1 = chandef->chan->center_freq;
734 		chandef->freq1_offset = chandef->chan->freq_offset;
735 		chandef->center_freq2 = 0;
736 
737 		/* NOTE: Disabling radar is only valid here for
738 		 * single channel context. To be sure, check it ...
739 		 */
740 		WARN_ON(local->hw.conf.radar_enabled &&
741 			!list_empty(&local->chanctx_list));
742 
743 		local->hw.conf.radar_enabled = false;
744 
745 		ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
746 	} else {
747 		drv_remove_chanctx(local, ctx);
748 	}
749 
750 	ieee80211_recalc_idle(local);
751 }
752 
753 static void ieee80211_free_chanctx(struct ieee80211_local *local,
754 				   struct ieee80211_chanctx *ctx)
755 {
756 	lockdep_assert_held(&local->chanctx_mtx);
757 
758 	WARN_ON_ONCE(ieee80211_chanctx_refcount(local, ctx) != 0);
759 
760 	list_del_rcu(&ctx->list);
761 	ieee80211_del_chanctx(local, ctx);
762 	kfree_rcu(ctx, rcu_head);
763 }
764 
765 void ieee80211_recalc_chanctx_chantype(struct ieee80211_local *local,
766 				       struct ieee80211_chanctx *ctx)
767 {
768 	struct ieee80211_chanctx_conf *conf = &ctx->conf;
769 	struct ieee80211_sub_if_data *sdata;
770 	const struct cfg80211_chan_def *compat = NULL;
771 	struct sta_info *sta;
772 
773 	lockdep_assert_held(&local->chanctx_mtx);
774 
775 	rcu_read_lock();
776 	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
777 		int link_id;
778 
779 		if (!ieee80211_sdata_running(sdata))
780 			continue;
781 
782 		if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
783 			continue;
784 
785 		for (link_id = 0; link_id < ARRAY_SIZE(sdata->link); link_id++) {
786 			struct ieee80211_bss_conf *link_conf =
787 				rcu_dereference(sdata->vif.link_conf[link_id]);
788 
789 			if (!link_conf)
790 				continue;
791 
792 			if (rcu_access_pointer(link_conf->chanctx_conf) != conf)
793 				continue;
794 
795 			if (!compat)
796 				compat = &link_conf->chandef;
797 
798 			compat = cfg80211_chandef_compatible(&link_conf->chandef,
799 							     compat);
800 			if (WARN_ON_ONCE(!compat))
801 				break;
802 		}
803 	}
804 
805 	/* TDLS peers can sometimes affect the chandef width */
806 	list_for_each_entry_rcu(sta, &local->sta_list, list) {
807 		if (!sta->uploaded ||
808 		    !test_sta_flag(sta, WLAN_STA_TDLS_WIDER_BW) ||
809 		    !test_sta_flag(sta, WLAN_STA_AUTHORIZED) ||
810 		    !sta->tdls_chandef.chan)
811 			continue;
812 
813 		compat = cfg80211_chandef_compatible(&sta->tdls_chandef,
814 						     compat);
815 		if (WARN_ON_ONCE(!compat))
816 			break;
817 	}
818 	rcu_read_unlock();
819 
820 	if (!compat)
821 		return;
822 
823 	ieee80211_change_chanctx(local, ctx, ctx, compat);
824 }
825 
826 static void ieee80211_recalc_radar_chanctx(struct ieee80211_local *local,
827 					   struct ieee80211_chanctx *chanctx)
828 {
829 	bool radar_enabled;
830 
831 	lockdep_assert_held(&local->chanctx_mtx);
832 	/* for ieee80211_is_radar_required */
833 	lockdep_assert_held(&local->mtx);
834 
835 	radar_enabled = ieee80211_chanctx_radar_required(local, chanctx);
836 
837 	if (radar_enabled == chanctx->conf.radar_enabled)
838 		return;
839 
840 	chanctx->conf.radar_enabled = radar_enabled;
841 
842 	if (!local->use_chanctx) {
843 		local->hw.conf.radar_enabled = chanctx->conf.radar_enabled;
844 		ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
845 	}
846 
847 	drv_change_chanctx(local, chanctx, IEEE80211_CHANCTX_CHANGE_RADAR);
848 }
849 
850 static int ieee80211_assign_link_chanctx(struct ieee80211_link_data *link,
851 					 struct ieee80211_chanctx *new_ctx)
852 {
853 	struct ieee80211_sub_if_data *sdata = link->sdata;
854 	struct ieee80211_local *local = sdata->local;
855 	struct ieee80211_chanctx_conf *conf;
856 	struct ieee80211_chanctx *curr_ctx = NULL;
857 	int ret = 0;
858 
859 	if (WARN_ON(sdata->vif.type == NL80211_IFTYPE_NAN))
860 		return -ENOTSUPP;
861 
862 	conf = rcu_dereference_protected(link->conf->chanctx_conf,
863 					 lockdep_is_held(&local->chanctx_mtx));
864 
865 	if (conf) {
866 		curr_ctx = container_of(conf, struct ieee80211_chanctx, conf);
867 
868 		drv_unassign_vif_chanctx(local, sdata, link->conf, curr_ctx);
869 		conf = NULL;
870 		list_del(&link->assigned_chanctx_list);
871 	}
872 
873 	if (new_ctx) {
874 		/* recalc considering the link we'll use it for now */
875 		ieee80211_recalc_chanctx_min_def(local, new_ctx, link);
876 
877 		ret = drv_assign_vif_chanctx(local, sdata, link->conf, new_ctx);
878 		if (ret)
879 			goto out;
880 
881 		conf = &new_ctx->conf;
882 		list_add(&link->assigned_chanctx_list,
883 			 &new_ctx->assigned_links);
884 	}
885 
886 out:
887 	rcu_assign_pointer(link->conf->chanctx_conf, conf);
888 
889 	sdata->vif.cfg.idle = !conf;
890 
891 	if (curr_ctx && ieee80211_chanctx_num_assigned(local, curr_ctx) > 0) {
892 		ieee80211_recalc_chanctx_chantype(local, curr_ctx);
893 		ieee80211_recalc_smps_chanctx(local, curr_ctx);
894 		ieee80211_recalc_radar_chanctx(local, curr_ctx);
895 		ieee80211_recalc_chanctx_min_def(local, curr_ctx, NULL);
896 	}
897 
898 	if (new_ctx && ieee80211_chanctx_num_assigned(local, new_ctx) > 0) {
899 		ieee80211_recalc_txpower(sdata, false);
900 		ieee80211_recalc_chanctx_min_def(local, new_ctx, NULL);
901 	}
902 
903 	if (sdata->vif.type != NL80211_IFTYPE_P2P_DEVICE &&
904 	    sdata->vif.type != NL80211_IFTYPE_MONITOR)
905 		ieee80211_vif_cfg_change_notify(sdata, BSS_CHANGED_IDLE);
906 
907 	ieee80211_check_fast_xmit_iface(sdata);
908 
909 	return ret;
910 }
911 
912 void ieee80211_recalc_smps_chanctx(struct ieee80211_local *local,
913 				   struct ieee80211_chanctx *chanctx)
914 {
915 	struct ieee80211_sub_if_data *sdata;
916 	u8 rx_chains_static, rx_chains_dynamic;
917 
918 	lockdep_assert_held(&local->chanctx_mtx);
919 
920 	rx_chains_static = 1;
921 	rx_chains_dynamic = 1;
922 
923 	rcu_read_lock();
924 	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
925 		u8 needed_static, needed_dynamic;
926 		unsigned int link_id;
927 
928 		if (!ieee80211_sdata_running(sdata))
929 			continue;
930 
931 		switch (sdata->vif.type) {
932 		case NL80211_IFTYPE_STATION:
933 			if (!sdata->u.mgd.associated)
934 				continue;
935 			break;
936 		case NL80211_IFTYPE_AP:
937 		case NL80211_IFTYPE_ADHOC:
938 		case NL80211_IFTYPE_MESH_POINT:
939 		case NL80211_IFTYPE_OCB:
940 			break;
941 		default:
942 			continue;
943 		}
944 
945 		for (link_id = 0; link_id < ARRAY_SIZE(sdata->link); link_id++) {
946 			struct ieee80211_link_data *link;
947 
948 			link = rcu_dereference(sdata->link[link_id]);
949 
950 			if (!link)
951 				continue;
952 
953 			if (rcu_access_pointer(link->conf->chanctx_conf) != &chanctx->conf)
954 				continue;
955 
956 			switch (link->smps_mode) {
957 			default:
958 				WARN_ONCE(1, "Invalid SMPS mode %d\n",
959 					  link->smps_mode);
960 				fallthrough;
961 			case IEEE80211_SMPS_OFF:
962 				needed_static = link->needed_rx_chains;
963 				needed_dynamic = link->needed_rx_chains;
964 				break;
965 			case IEEE80211_SMPS_DYNAMIC:
966 				needed_static = 1;
967 				needed_dynamic = link->needed_rx_chains;
968 				break;
969 			case IEEE80211_SMPS_STATIC:
970 				needed_static = 1;
971 				needed_dynamic = 1;
972 				break;
973 			}
974 
975 			rx_chains_static = max(rx_chains_static, needed_static);
976 			rx_chains_dynamic = max(rx_chains_dynamic, needed_dynamic);
977 		}
978 	}
979 
980 	/* Disable SMPS for the monitor interface */
981 	sdata = rcu_dereference(local->monitor_sdata);
982 	if (sdata &&
983 	    rcu_access_pointer(sdata->vif.bss_conf.chanctx_conf) == &chanctx->conf)
984 		rx_chains_dynamic = rx_chains_static = local->rx_chains;
985 
986 	rcu_read_unlock();
987 
988 	if (!local->use_chanctx) {
989 		if (rx_chains_static > 1)
990 			local->smps_mode = IEEE80211_SMPS_OFF;
991 		else if (rx_chains_dynamic > 1)
992 			local->smps_mode = IEEE80211_SMPS_DYNAMIC;
993 		else
994 			local->smps_mode = IEEE80211_SMPS_STATIC;
995 		ieee80211_hw_config(local, 0);
996 	}
997 
998 	if (rx_chains_static == chanctx->conf.rx_chains_static &&
999 	    rx_chains_dynamic == chanctx->conf.rx_chains_dynamic)
1000 		return;
1001 
1002 	chanctx->conf.rx_chains_static = rx_chains_static;
1003 	chanctx->conf.rx_chains_dynamic = rx_chains_dynamic;
1004 	drv_change_chanctx(local, chanctx, IEEE80211_CHANCTX_CHANGE_RX_CHAINS);
1005 }
1006 
1007 static void
1008 __ieee80211_link_copy_chanctx_to_vlans(struct ieee80211_link_data *link,
1009 				       bool clear)
1010 {
1011 	struct ieee80211_sub_if_data *sdata = link->sdata;
1012 	unsigned int link_id = link->link_id;
1013 	struct ieee80211_bss_conf *link_conf = link->conf;
1014 	struct ieee80211_local *local __maybe_unused = sdata->local;
1015 	struct ieee80211_sub_if_data *vlan;
1016 	struct ieee80211_chanctx_conf *conf;
1017 
1018 	if (WARN_ON(sdata->vif.type != NL80211_IFTYPE_AP))
1019 		return;
1020 
1021 	lockdep_assert_held(&local->mtx);
1022 
1023 	/* Check that conf exists, even when clearing this function
1024 	 * must be called with the AP's channel context still there
1025 	 * as it would otherwise cause VLANs to have an invalid
1026 	 * channel context pointer for a while, possibly pointing
1027 	 * to a channel context that has already been freed.
1028 	 */
1029 	conf = rcu_dereference_protected(link_conf->chanctx_conf,
1030 					 lockdep_is_held(&local->chanctx_mtx));
1031 	WARN_ON(!conf);
1032 
1033 	if (clear)
1034 		conf = NULL;
1035 
1036 	rcu_read_lock();
1037 	list_for_each_entry(vlan, &sdata->u.ap.vlans, u.vlan.list) {
1038 		struct ieee80211_bss_conf *vlan_conf;
1039 
1040 		vlan_conf = rcu_dereference(vlan->vif.link_conf[link_id]);
1041 		if (WARN_ON(!vlan_conf))
1042 			continue;
1043 
1044 		rcu_assign_pointer(vlan_conf->chanctx_conf, conf);
1045 	}
1046 	rcu_read_unlock();
1047 }
1048 
1049 void ieee80211_link_copy_chanctx_to_vlans(struct ieee80211_link_data *link,
1050 					  bool clear)
1051 {
1052 	struct ieee80211_local *local = link->sdata->local;
1053 
1054 	mutex_lock(&local->chanctx_mtx);
1055 
1056 	__ieee80211_link_copy_chanctx_to_vlans(link, clear);
1057 
1058 	mutex_unlock(&local->chanctx_mtx);
1059 }
1060 
1061 int ieee80211_link_unreserve_chanctx(struct ieee80211_link_data *link)
1062 {
1063 	struct ieee80211_sub_if_data *sdata = link->sdata;
1064 	struct ieee80211_chanctx *ctx = link->reserved_chanctx;
1065 
1066 	lockdep_assert_held(&sdata->local->chanctx_mtx);
1067 
1068 	if (WARN_ON(!ctx))
1069 		return -EINVAL;
1070 
1071 	list_del(&link->reserved_chanctx_list);
1072 	link->reserved_chanctx = NULL;
1073 
1074 	if (ieee80211_chanctx_refcount(sdata->local, ctx) == 0) {
1075 		if (ctx->replace_state == IEEE80211_CHANCTX_REPLACES_OTHER) {
1076 			if (WARN_ON(!ctx->replace_ctx))
1077 				return -EINVAL;
1078 
1079 			WARN_ON(ctx->replace_ctx->replace_state !=
1080 			        IEEE80211_CHANCTX_WILL_BE_REPLACED);
1081 			WARN_ON(ctx->replace_ctx->replace_ctx != ctx);
1082 
1083 			ctx->replace_ctx->replace_ctx = NULL;
1084 			ctx->replace_ctx->replace_state =
1085 					IEEE80211_CHANCTX_REPLACE_NONE;
1086 
1087 			list_del_rcu(&ctx->list);
1088 			kfree_rcu(ctx, rcu_head);
1089 		} else {
1090 			ieee80211_free_chanctx(sdata->local, ctx);
1091 		}
1092 	}
1093 
1094 	return 0;
1095 }
1096 
1097 int ieee80211_link_reserve_chanctx(struct ieee80211_link_data *link,
1098 				   const struct cfg80211_chan_def *chandef,
1099 				   enum ieee80211_chanctx_mode mode,
1100 				   bool radar_required)
1101 {
1102 	struct ieee80211_sub_if_data *sdata = link->sdata;
1103 	struct ieee80211_local *local = sdata->local;
1104 	struct ieee80211_chanctx *new_ctx, *curr_ctx, *ctx;
1105 
1106 	lockdep_assert_held(&local->chanctx_mtx);
1107 
1108 	curr_ctx = ieee80211_link_get_chanctx(link);
1109 	if (curr_ctx && local->use_chanctx && !local->ops->switch_vif_chanctx)
1110 		return -ENOTSUPP;
1111 
1112 	new_ctx = ieee80211_find_reservation_chanctx(local, chandef, mode);
1113 	if (!new_ctx) {
1114 		if (ieee80211_can_create_new_chanctx(local)) {
1115 			new_ctx = ieee80211_new_chanctx(local, chandef, mode);
1116 			if (IS_ERR(new_ctx))
1117 				return PTR_ERR(new_ctx);
1118 		} else {
1119 			if (!curr_ctx ||
1120 			    (curr_ctx->replace_state ==
1121 			     IEEE80211_CHANCTX_WILL_BE_REPLACED) ||
1122 			    !list_empty(&curr_ctx->reserved_links)) {
1123 				/*
1124 				 * Another link already requested this context
1125 				 * for a reservation. Find another one hoping
1126 				 * all links assigned to it will also switch
1127 				 * soon enough.
1128 				 *
1129 				 * TODO: This needs a little more work as some
1130 				 * cases (more than 2 chanctx capable devices)
1131 				 * may fail which could otherwise succeed
1132 				 * provided some channel context juggling was
1133 				 * performed.
1134 				 *
1135 				 * Consider ctx1..3, link1..6, each ctx has 2
1136 				 * links. link1 and link2 from ctx1 request new
1137 				 * different chandefs starting 2 in-place
1138 				 * reserations with ctx4 and ctx5 replacing
1139 				 * ctx1 and ctx2 respectively. Next link5 and
1140 				 * link6 from ctx3 reserve ctx4. If link3 and
1141 				 * link4 remain on ctx2 as they are then this
1142 				 * fails unless `replace_ctx` from ctx5 is
1143 				 * replaced with ctx3.
1144 				 */
1145 				list_for_each_entry(ctx, &local->chanctx_list,
1146 						    list) {
1147 					if (ctx->replace_state !=
1148 					    IEEE80211_CHANCTX_REPLACE_NONE)
1149 						continue;
1150 
1151 					if (!list_empty(&ctx->reserved_links))
1152 						continue;
1153 
1154 					curr_ctx = ctx;
1155 					break;
1156 				}
1157 			}
1158 
1159 			/*
1160 			 * If that's true then all available contexts already
1161 			 * have reservations and cannot be used.
1162 			 */
1163 			if (!curr_ctx ||
1164 			    (curr_ctx->replace_state ==
1165 			     IEEE80211_CHANCTX_WILL_BE_REPLACED) ||
1166 			    !list_empty(&curr_ctx->reserved_links))
1167 				return -EBUSY;
1168 
1169 			new_ctx = ieee80211_alloc_chanctx(local, chandef, mode);
1170 			if (!new_ctx)
1171 				return -ENOMEM;
1172 
1173 			new_ctx->replace_ctx = curr_ctx;
1174 			new_ctx->replace_state =
1175 					IEEE80211_CHANCTX_REPLACES_OTHER;
1176 
1177 			curr_ctx->replace_ctx = new_ctx;
1178 			curr_ctx->replace_state =
1179 					IEEE80211_CHANCTX_WILL_BE_REPLACED;
1180 
1181 			list_add_rcu(&new_ctx->list, &local->chanctx_list);
1182 		}
1183 	}
1184 
1185 	list_add(&link->reserved_chanctx_list, &new_ctx->reserved_links);
1186 	link->reserved_chanctx = new_ctx;
1187 	link->reserved_chandef = *chandef;
1188 	link->reserved_radar_required = radar_required;
1189 	link->reserved_ready = false;
1190 
1191 	return 0;
1192 }
1193 
1194 static void
1195 ieee80211_link_chanctx_reservation_complete(struct ieee80211_link_data *link)
1196 {
1197 	struct ieee80211_sub_if_data *sdata = link->sdata;
1198 
1199 	switch (sdata->vif.type) {
1200 	case NL80211_IFTYPE_ADHOC:
1201 	case NL80211_IFTYPE_AP:
1202 	case NL80211_IFTYPE_MESH_POINT:
1203 	case NL80211_IFTYPE_OCB:
1204 		ieee80211_queue_work(&sdata->local->hw,
1205 				     &link->csa_finalize_work);
1206 		break;
1207 	case NL80211_IFTYPE_STATION:
1208 		ieee80211_queue_work(&sdata->local->hw,
1209 				     &link->u.mgd.chswitch_work);
1210 		break;
1211 	case NL80211_IFTYPE_UNSPECIFIED:
1212 	case NL80211_IFTYPE_AP_VLAN:
1213 	case NL80211_IFTYPE_WDS:
1214 	case NL80211_IFTYPE_MONITOR:
1215 	case NL80211_IFTYPE_P2P_CLIENT:
1216 	case NL80211_IFTYPE_P2P_GO:
1217 	case NL80211_IFTYPE_P2P_DEVICE:
1218 	case NL80211_IFTYPE_NAN:
1219 	case NUM_NL80211_IFTYPES:
1220 		WARN_ON(1);
1221 		break;
1222 	}
1223 }
1224 
1225 static void
1226 ieee80211_link_update_chandef(struct ieee80211_link_data *link,
1227 			      const struct cfg80211_chan_def *chandef)
1228 {
1229 	struct ieee80211_sub_if_data *sdata = link->sdata;
1230 	unsigned int link_id = link->link_id;
1231 	struct ieee80211_sub_if_data *vlan;
1232 
1233 	link->conf->chandef = *chandef;
1234 
1235 	if (sdata->vif.type != NL80211_IFTYPE_AP)
1236 		return;
1237 
1238 	rcu_read_lock();
1239 	list_for_each_entry(vlan, &sdata->u.ap.vlans, u.vlan.list) {
1240 		struct ieee80211_bss_conf *vlan_conf;
1241 
1242 		vlan_conf = rcu_dereference(vlan->vif.link_conf[link_id]);
1243 		if (WARN_ON(!vlan_conf))
1244 			continue;
1245 
1246 		vlan_conf->chandef = *chandef;
1247 	}
1248 	rcu_read_unlock();
1249 }
1250 
1251 static int
1252 ieee80211_link_use_reserved_reassign(struct ieee80211_link_data *link)
1253 {
1254 	struct ieee80211_sub_if_data *sdata = link->sdata;
1255 	struct ieee80211_bss_conf *link_conf = link->conf;
1256 	struct ieee80211_local *local = sdata->local;
1257 	struct ieee80211_vif_chanctx_switch vif_chsw[1] = {};
1258 	struct ieee80211_chanctx *old_ctx, *new_ctx;
1259 	const struct cfg80211_chan_def *chandef;
1260 	u32 changed = 0;
1261 	int err;
1262 
1263 	lockdep_assert_held(&local->mtx);
1264 	lockdep_assert_held(&local->chanctx_mtx);
1265 
1266 	new_ctx = link->reserved_chanctx;
1267 	old_ctx = ieee80211_link_get_chanctx(link);
1268 
1269 	if (WARN_ON(!link->reserved_ready))
1270 		return -EBUSY;
1271 
1272 	if (WARN_ON(!new_ctx))
1273 		return -EINVAL;
1274 
1275 	if (WARN_ON(!old_ctx))
1276 		return -EINVAL;
1277 
1278 	if (WARN_ON(new_ctx->replace_state ==
1279 		    IEEE80211_CHANCTX_REPLACES_OTHER))
1280 		return -EINVAL;
1281 
1282 	chandef = ieee80211_chanctx_non_reserved_chandef(local, new_ctx,
1283 				&link->reserved_chandef);
1284 	if (WARN_ON(!chandef))
1285 		return -EINVAL;
1286 
1287 	if (link_conf->chandef.width != link->reserved_chandef.width)
1288 		changed = BSS_CHANGED_BANDWIDTH;
1289 
1290 	ieee80211_link_update_chandef(link, &link->reserved_chandef);
1291 
1292 	_ieee80211_change_chanctx(local, new_ctx, old_ctx, chandef, link);
1293 
1294 	vif_chsw[0].vif = &sdata->vif;
1295 	vif_chsw[0].old_ctx = &old_ctx->conf;
1296 	vif_chsw[0].new_ctx = &new_ctx->conf;
1297 	vif_chsw[0].link_conf = link->conf;
1298 
1299 	list_del(&link->reserved_chanctx_list);
1300 	link->reserved_chanctx = NULL;
1301 
1302 	err = drv_switch_vif_chanctx(local, vif_chsw, 1,
1303 				     CHANCTX_SWMODE_REASSIGN_VIF);
1304 	if (err) {
1305 		if (ieee80211_chanctx_refcount(local, new_ctx) == 0)
1306 			ieee80211_free_chanctx(local, new_ctx);
1307 
1308 		goto out;
1309 	}
1310 
1311 	list_move(&link->assigned_chanctx_list, &new_ctx->assigned_links);
1312 	rcu_assign_pointer(link_conf->chanctx_conf, &new_ctx->conf);
1313 
1314 	if (sdata->vif.type == NL80211_IFTYPE_AP)
1315 		__ieee80211_link_copy_chanctx_to_vlans(link, false);
1316 
1317 	ieee80211_check_fast_xmit_iface(sdata);
1318 
1319 	if (ieee80211_chanctx_refcount(local, old_ctx) == 0)
1320 		ieee80211_free_chanctx(local, old_ctx);
1321 
1322 	ieee80211_recalc_chanctx_min_def(local, new_ctx, NULL);
1323 	ieee80211_recalc_smps_chanctx(local, new_ctx);
1324 	ieee80211_recalc_radar_chanctx(local, new_ctx);
1325 
1326 	if (changed)
1327 		ieee80211_link_info_change_notify(sdata, link, changed);
1328 
1329 out:
1330 	ieee80211_link_chanctx_reservation_complete(link);
1331 	return err;
1332 }
1333 
1334 static int
1335 ieee80211_link_use_reserved_assign(struct ieee80211_link_data *link)
1336 {
1337 	struct ieee80211_sub_if_data *sdata = link->sdata;
1338 	struct ieee80211_local *local = sdata->local;
1339 	struct ieee80211_chanctx *old_ctx, *new_ctx;
1340 	const struct cfg80211_chan_def *chandef;
1341 	int err;
1342 
1343 	old_ctx = ieee80211_link_get_chanctx(link);
1344 	new_ctx = link->reserved_chanctx;
1345 
1346 	if (WARN_ON(!link->reserved_ready))
1347 		return -EINVAL;
1348 
1349 	if (WARN_ON(old_ctx))
1350 		return -EINVAL;
1351 
1352 	if (WARN_ON(!new_ctx))
1353 		return -EINVAL;
1354 
1355 	if (WARN_ON(new_ctx->replace_state ==
1356 		    IEEE80211_CHANCTX_REPLACES_OTHER))
1357 		return -EINVAL;
1358 
1359 	chandef = ieee80211_chanctx_non_reserved_chandef(local, new_ctx,
1360 				&link->reserved_chandef);
1361 	if (WARN_ON(!chandef))
1362 		return -EINVAL;
1363 
1364 	ieee80211_change_chanctx(local, new_ctx, new_ctx, chandef);
1365 
1366 	list_del(&link->reserved_chanctx_list);
1367 	link->reserved_chanctx = NULL;
1368 
1369 	err = ieee80211_assign_link_chanctx(link, new_ctx);
1370 	if (err) {
1371 		if (ieee80211_chanctx_refcount(local, new_ctx) == 0)
1372 			ieee80211_free_chanctx(local, new_ctx);
1373 
1374 		goto out;
1375 	}
1376 
1377 out:
1378 	ieee80211_link_chanctx_reservation_complete(link);
1379 	return err;
1380 }
1381 
1382 static bool
1383 ieee80211_link_has_in_place_reservation(struct ieee80211_link_data *link)
1384 {
1385 	struct ieee80211_sub_if_data *sdata = link->sdata;
1386 	struct ieee80211_chanctx *old_ctx, *new_ctx;
1387 
1388 	lockdep_assert_held(&sdata->local->chanctx_mtx);
1389 
1390 	new_ctx = link->reserved_chanctx;
1391 	old_ctx = ieee80211_link_get_chanctx(link);
1392 
1393 	if (!old_ctx)
1394 		return false;
1395 
1396 	if (WARN_ON(!new_ctx))
1397 		return false;
1398 
1399 	if (old_ctx->replace_state != IEEE80211_CHANCTX_WILL_BE_REPLACED)
1400 		return false;
1401 
1402 	if (new_ctx->replace_state != IEEE80211_CHANCTX_REPLACES_OTHER)
1403 		return false;
1404 
1405 	return true;
1406 }
1407 
1408 static int ieee80211_chsw_switch_hwconf(struct ieee80211_local *local,
1409 					struct ieee80211_chanctx *new_ctx)
1410 {
1411 	const struct cfg80211_chan_def *chandef;
1412 
1413 	lockdep_assert_held(&local->mtx);
1414 	lockdep_assert_held(&local->chanctx_mtx);
1415 
1416 	chandef = ieee80211_chanctx_reserved_chandef(local, new_ctx, NULL);
1417 	if (WARN_ON(!chandef))
1418 		return -EINVAL;
1419 
1420 	local->hw.conf.radar_enabled = new_ctx->conf.radar_enabled;
1421 	local->_oper_chandef = *chandef;
1422 	ieee80211_hw_config(local, 0);
1423 
1424 	return 0;
1425 }
1426 
1427 static int ieee80211_chsw_switch_vifs(struct ieee80211_local *local,
1428 				      int n_vifs)
1429 {
1430 	struct ieee80211_vif_chanctx_switch *vif_chsw;
1431 	struct ieee80211_link_data *link;
1432 	struct ieee80211_chanctx *ctx, *old_ctx;
1433 	int i, err;
1434 
1435 	lockdep_assert_held(&local->mtx);
1436 	lockdep_assert_held(&local->chanctx_mtx);
1437 
1438 	vif_chsw = kcalloc(n_vifs, sizeof(vif_chsw[0]), GFP_KERNEL);
1439 	if (!vif_chsw)
1440 		return -ENOMEM;
1441 
1442 	i = 0;
1443 	list_for_each_entry(ctx, &local->chanctx_list, list) {
1444 		if (ctx->replace_state != IEEE80211_CHANCTX_REPLACES_OTHER)
1445 			continue;
1446 
1447 		if (WARN_ON(!ctx->replace_ctx)) {
1448 			err = -EINVAL;
1449 			goto out;
1450 		}
1451 
1452 		list_for_each_entry(link, &ctx->reserved_links,
1453 				    reserved_chanctx_list) {
1454 			if (!ieee80211_link_has_in_place_reservation(link))
1455 				continue;
1456 
1457 			old_ctx = ieee80211_link_get_chanctx(link);
1458 			vif_chsw[i].vif = &link->sdata->vif;
1459 			vif_chsw[i].old_ctx = &old_ctx->conf;
1460 			vif_chsw[i].new_ctx = &ctx->conf;
1461 			vif_chsw[i].link_conf = link->conf;
1462 
1463 			i++;
1464 		}
1465 	}
1466 
1467 	err = drv_switch_vif_chanctx(local, vif_chsw, n_vifs,
1468 				     CHANCTX_SWMODE_SWAP_CONTEXTS);
1469 
1470 out:
1471 	kfree(vif_chsw);
1472 	return err;
1473 }
1474 
1475 static int ieee80211_chsw_switch_ctxs(struct ieee80211_local *local)
1476 {
1477 	struct ieee80211_chanctx *ctx;
1478 	int err;
1479 
1480 	lockdep_assert_held(&local->mtx);
1481 	lockdep_assert_held(&local->chanctx_mtx);
1482 
1483 	list_for_each_entry(ctx, &local->chanctx_list, list) {
1484 		if (ctx->replace_state != IEEE80211_CHANCTX_REPLACES_OTHER)
1485 			continue;
1486 
1487 		if (!list_empty(&ctx->replace_ctx->assigned_links))
1488 			continue;
1489 
1490 		ieee80211_del_chanctx(local, ctx->replace_ctx);
1491 		err = ieee80211_add_chanctx(local, ctx);
1492 		if (err)
1493 			goto err;
1494 	}
1495 
1496 	return 0;
1497 
1498 err:
1499 	WARN_ON(ieee80211_add_chanctx(local, ctx));
1500 	list_for_each_entry_continue_reverse(ctx, &local->chanctx_list, list) {
1501 		if (ctx->replace_state != IEEE80211_CHANCTX_REPLACES_OTHER)
1502 			continue;
1503 
1504 		if (!list_empty(&ctx->replace_ctx->assigned_links))
1505 			continue;
1506 
1507 		ieee80211_del_chanctx(local, ctx);
1508 		WARN_ON(ieee80211_add_chanctx(local, ctx->replace_ctx));
1509 	}
1510 
1511 	return err;
1512 }
1513 
1514 static int ieee80211_vif_use_reserved_switch(struct ieee80211_local *local)
1515 {
1516 	struct ieee80211_chanctx *ctx, *ctx_tmp, *old_ctx;
1517 	struct ieee80211_chanctx *new_ctx = NULL;
1518 	int err, n_assigned, n_reserved, n_ready;
1519 	int n_ctx = 0, n_vifs_switch = 0, n_vifs_assign = 0, n_vifs_ctxless = 0;
1520 
1521 	lockdep_assert_held(&local->mtx);
1522 	lockdep_assert_held(&local->chanctx_mtx);
1523 
1524 	/*
1525 	 * If there are 2 independent pairs of channel contexts performing
1526 	 * cross-switch of their vifs this code will still wait until both are
1527 	 * ready even though it could be possible to switch one before the
1528 	 * other is ready.
1529 	 *
1530 	 * For practical reasons and code simplicity just do a single huge
1531 	 * switch.
1532 	 */
1533 
1534 	/*
1535 	 * Verify if the reservation is still feasible.
1536 	 *  - if it's not then disconnect
1537 	 *  - if it is but not all vifs necessary are ready then defer
1538 	 */
1539 
1540 	list_for_each_entry(ctx, &local->chanctx_list, list) {
1541 		struct ieee80211_link_data *link;
1542 
1543 		if (ctx->replace_state != IEEE80211_CHANCTX_REPLACES_OTHER)
1544 			continue;
1545 
1546 		if (WARN_ON(!ctx->replace_ctx)) {
1547 			err = -EINVAL;
1548 			goto err;
1549 		}
1550 
1551 		if (!local->use_chanctx)
1552 			new_ctx = ctx;
1553 
1554 		n_ctx++;
1555 
1556 		n_assigned = 0;
1557 		n_reserved = 0;
1558 		n_ready = 0;
1559 
1560 		list_for_each_entry(link, &ctx->replace_ctx->assigned_links,
1561 				    assigned_chanctx_list) {
1562 			n_assigned++;
1563 			if (link->reserved_chanctx) {
1564 				n_reserved++;
1565 				if (link->reserved_ready)
1566 					n_ready++;
1567 			}
1568 		}
1569 
1570 		if (n_assigned != n_reserved) {
1571 			if (n_ready == n_reserved) {
1572 				wiphy_info(local->hw.wiphy,
1573 					   "channel context reservation cannot be finalized because some interfaces aren't switching\n");
1574 				err = -EBUSY;
1575 				goto err;
1576 			}
1577 
1578 			return -EAGAIN;
1579 		}
1580 
1581 		ctx->conf.radar_enabled = false;
1582 		list_for_each_entry(link, &ctx->reserved_links,
1583 				    reserved_chanctx_list) {
1584 			if (ieee80211_link_has_in_place_reservation(link) &&
1585 			    !link->reserved_ready)
1586 				return -EAGAIN;
1587 
1588 			old_ctx = ieee80211_link_get_chanctx(link);
1589 			if (old_ctx) {
1590 				if (old_ctx->replace_state ==
1591 				    IEEE80211_CHANCTX_WILL_BE_REPLACED)
1592 					n_vifs_switch++;
1593 				else
1594 					n_vifs_assign++;
1595 			} else {
1596 				n_vifs_ctxless++;
1597 			}
1598 
1599 			if (link->reserved_radar_required)
1600 				ctx->conf.radar_enabled = true;
1601 		}
1602 	}
1603 
1604 	if (WARN_ON(n_ctx == 0) ||
1605 	    WARN_ON(n_vifs_switch == 0 &&
1606 		    n_vifs_assign == 0 &&
1607 		    n_vifs_ctxless == 0) ||
1608 	    WARN_ON(n_ctx > 1 && !local->use_chanctx) ||
1609 	    WARN_ON(!new_ctx && !local->use_chanctx)) {
1610 		err = -EINVAL;
1611 		goto err;
1612 	}
1613 
1614 	/*
1615 	 * All necessary vifs are ready. Perform the switch now depending on
1616 	 * reservations and driver capabilities.
1617 	 */
1618 
1619 	if (local->use_chanctx) {
1620 		if (n_vifs_switch > 0) {
1621 			err = ieee80211_chsw_switch_vifs(local, n_vifs_switch);
1622 			if (err)
1623 				goto err;
1624 		}
1625 
1626 		if (n_vifs_assign > 0 || n_vifs_ctxless > 0) {
1627 			err = ieee80211_chsw_switch_ctxs(local);
1628 			if (err)
1629 				goto err;
1630 		}
1631 	} else {
1632 		err = ieee80211_chsw_switch_hwconf(local, new_ctx);
1633 		if (err)
1634 			goto err;
1635 	}
1636 
1637 	/*
1638 	 * Update all structures, values and pointers to point to new channel
1639 	 * context(s).
1640 	 */
1641 	list_for_each_entry(ctx, &local->chanctx_list, list) {
1642 		struct ieee80211_link_data *link, *link_tmp;
1643 
1644 		if (ctx->replace_state != IEEE80211_CHANCTX_REPLACES_OTHER)
1645 			continue;
1646 
1647 		if (WARN_ON(!ctx->replace_ctx)) {
1648 			err = -EINVAL;
1649 			goto err;
1650 		}
1651 
1652 		list_for_each_entry(link, &ctx->reserved_links,
1653 				    reserved_chanctx_list) {
1654 			struct ieee80211_sub_if_data *sdata = link->sdata;
1655 			struct ieee80211_bss_conf *link_conf = link->conf;
1656 			u32 changed = 0;
1657 
1658 			if (!ieee80211_link_has_in_place_reservation(link))
1659 				continue;
1660 
1661 			rcu_assign_pointer(link_conf->chanctx_conf,
1662 					   &ctx->conf);
1663 
1664 			if (sdata->vif.type == NL80211_IFTYPE_AP)
1665 				__ieee80211_link_copy_chanctx_to_vlans(link,
1666 								       false);
1667 
1668 			ieee80211_check_fast_xmit_iface(sdata);
1669 
1670 			link->radar_required = link->reserved_radar_required;
1671 
1672 			if (link_conf->chandef.width != link->reserved_chandef.width)
1673 				changed = BSS_CHANGED_BANDWIDTH;
1674 
1675 			ieee80211_link_update_chandef(link, &link->reserved_chandef);
1676 			if (changed)
1677 				ieee80211_link_info_change_notify(sdata,
1678 								  link,
1679 								  changed);
1680 
1681 			ieee80211_recalc_txpower(sdata, false);
1682 		}
1683 
1684 		ieee80211_recalc_chanctx_chantype(local, ctx);
1685 		ieee80211_recalc_smps_chanctx(local, ctx);
1686 		ieee80211_recalc_radar_chanctx(local, ctx);
1687 		ieee80211_recalc_chanctx_min_def(local, ctx, NULL);
1688 
1689 		list_for_each_entry_safe(link, link_tmp, &ctx->reserved_links,
1690 					 reserved_chanctx_list) {
1691 			if (ieee80211_link_get_chanctx(link) != ctx)
1692 				continue;
1693 
1694 			list_del(&link->reserved_chanctx_list);
1695 			list_move(&link->assigned_chanctx_list,
1696 				  &ctx->assigned_links);
1697 			link->reserved_chanctx = NULL;
1698 
1699 			ieee80211_link_chanctx_reservation_complete(link);
1700 		}
1701 
1702 		/*
1703 		 * This context might have been a dependency for an already
1704 		 * ready re-assign reservation interface that was deferred. Do
1705 		 * not propagate error to the caller though. The in-place
1706 		 * reservation for originally requested interface has already
1707 		 * succeeded at this point.
1708 		 */
1709 		list_for_each_entry_safe(link, link_tmp, &ctx->reserved_links,
1710 					 reserved_chanctx_list) {
1711 			if (WARN_ON(ieee80211_link_has_in_place_reservation(link)))
1712 				continue;
1713 
1714 			if (WARN_ON(link->reserved_chanctx != ctx))
1715 				continue;
1716 
1717 			if (!link->reserved_ready)
1718 				continue;
1719 
1720 			if (ieee80211_link_get_chanctx(link))
1721 				err = ieee80211_link_use_reserved_reassign(link);
1722 			else
1723 				err = ieee80211_link_use_reserved_assign(link);
1724 
1725 			if (err) {
1726 				link_info(link,
1727 					  "failed to finalize (re-)assign reservation (err=%d)\n",
1728 					  err);
1729 				ieee80211_link_unreserve_chanctx(link);
1730 				cfg80211_stop_iface(local->hw.wiphy,
1731 						    &link->sdata->wdev,
1732 						    GFP_KERNEL);
1733 			}
1734 		}
1735 	}
1736 
1737 	/*
1738 	 * Finally free old contexts
1739 	 */
1740 
1741 	list_for_each_entry_safe(ctx, ctx_tmp, &local->chanctx_list, list) {
1742 		if (ctx->replace_state != IEEE80211_CHANCTX_WILL_BE_REPLACED)
1743 			continue;
1744 
1745 		ctx->replace_ctx->replace_ctx = NULL;
1746 		ctx->replace_ctx->replace_state =
1747 				IEEE80211_CHANCTX_REPLACE_NONE;
1748 
1749 		list_del_rcu(&ctx->list);
1750 		kfree_rcu(ctx, rcu_head);
1751 	}
1752 
1753 	return 0;
1754 
1755 err:
1756 	list_for_each_entry(ctx, &local->chanctx_list, list) {
1757 		struct ieee80211_link_data *link, *link_tmp;
1758 
1759 		if (ctx->replace_state != IEEE80211_CHANCTX_REPLACES_OTHER)
1760 			continue;
1761 
1762 		list_for_each_entry_safe(link, link_tmp, &ctx->reserved_links,
1763 					 reserved_chanctx_list) {
1764 			ieee80211_link_unreserve_chanctx(link);
1765 			ieee80211_link_chanctx_reservation_complete(link);
1766 		}
1767 	}
1768 
1769 	return err;
1770 }
1771 
1772 static void __ieee80211_link_release_channel(struct ieee80211_link_data *link)
1773 {
1774 	struct ieee80211_sub_if_data *sdata = link->sdata;
1775 	struct ieee80211_bss_conf *link_conf = link->conf;
1776 	struct ieee80211_local *local = sdata->local;
1777 	struct ieee80211_chanctx_conf *conf;
1778 	struct ieee80211_chanctx *ctx;
1779 	bool use_reserved_switch = false;
1780 
1781 	lockdep_assert_held(&local->chanctx_mtx);
1782 
1783 	conf = rcu_dereference_protected(link_conf->chanctx_conf,
1784 					 lockdep_is_held(&local->chanctx_mtx));
1785 	if (!conf)
1786 		return;
1787 
1788 	ctx = container_of(conf, struct ieee80211_chanctx, conf);
1789 
1790 	if (link->reserved_chanctx) {
1791 		if (link->reserved_chanctx->replace_state == IEEE80211_CHANCTX_REPLACES_OTHER &&
1792 		    ieee80211_chanctx_num_reserved(local, link->reserved_chanctx) > 1)
1793 			use_reserved_switch = true;
1794 
1795 		ieee80211_link_unreserve_chanctx(link);
1796 	}
1797 
1798 	ieee80211_assign_link_chanctx(link, NULL);
1799 	if (ieee80211_chanctx_refcount(local, ctx) == 0)
1800 		ieee80211_free_chanctx(local, ctx);
1801 
1802 	link->radar_required = false;
1803 
1804 	/* Unreserving may ready an in-place reservation. */
1805 	if (use_reserved_switch)
1806 		ieee80211_vif_use_reserved_switch(local);
1807 }
1808 
1809 int ieee80211_link_use_channel(struct ieee80211_link_data *link,
1810 			       const struct cfg80211_chan_def *chandef,
1811 			       enum ieee80211_chanctx_mode mode)
1812 {
1813 	struct ieee80211_sub_if_data *sdata = link->sdata;
1814 	struct ieee80211_local *local = sdata->local;
1815 	struct ieee80211_chanctx *ctx;
1816 	u8 radar_detect_width = 0;
1817 	int ret;
1818 
1819 	lockdep_assert_held(&local->mtx);
1820 
1821 	if (sdata->vif.active_links &&
1822 	    !(sdata->vif.active_links & BIT(link->link_id))) {
1823 		ieee80211_link_update_chandef(link, chandef);
1824 		return 0;
1825 	}
1826 
1827 	mutex_lock(&local->chanctx_mtx);
1828 
1829 	ret = cfg80211_chandef_dfs_required(local->hw.wiphy,
1830 					    chandef,
1831 					    sdata->wdev.iftype);
1832 	if (ret < 0)
1833 		goto out;
1834 	if (ret > 0)
1835 		radar_detect_width = BIT(chandef->width);
1836 
1837 	link->radar_required = ret;
1838 
1839 	ret = ieee80211_check_combinations(sdata, chandef, mode,
1840 					   radar_detect_width);
1841 	if (ret < 0)
1842 		goto out;
1843 
1844 	__ieee80211_link_release_channel(link);
1845 
1846 	ctx = ieee80211_find_chanctx(local, chandef, mode);
1847 	if (!ctx)
1848 		ctx = ieee80211_new_chanctx(local, chandef, mode);
1849 	if (IS_ERR(ctx)) {
1850 		ret = PTR_ERR(ctx);
1851 		goto out;
1852 	}
1853 
1854 	ieee80211_link_update_chandef(link, chandef);
1855 
1856 	ret = ieee80211_assign_link_chanctx(link, ctx);
1857 	if (ret) {
1858 		/* if assign fails refcount stays the same */
1859 		if (ieee80211_chanctx_refcount(local, ctx) == 0)
1860 			ieee80211_free_chanctx(local, ctx);
1861 		goto out;
1862 	}
1863 
1864 	ieee80211_recalc_smps_chanctx(local, ctx);
1865 	ieee80211_recalc_radar_chanctx(local, ctx);
1866  out:
1867 	if (ret)
1868 		link->radar_required = false;
1869 
1870 	mutex_unlock(&local->chanctx_mtx);
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_held(&local->mtx);
1883 	lockdep_assert_held(&local->chanctx_mtx);
1884 
1885 	new_ctx = link->reserved_chanctx;
1886 	old_ctx = ieee80211_link_get_chanctx(link);
1887 
1888 	if (WARN_ON(!new_ctx))
1889 		return -EINVAL;
1890 
1891 	if (WARN_ON(new_ctx->replace_state ==
1892 		    IEEE80211_CHANCTX_WILL_BE_REPLACED))
1893 		return -EINVAL;
1894 
1895 	if (WARN_ON(link->reserved_ready))
1896 		return -EINVAL;
1897 
1898 	link->reserved_ready = true;
1899 
1900 	if (new_ctx->replace_state == IEEE80211_CHANCTX_REPLACE_NONE) {
1901 		if (old_ctx)
1902 			return ieee80211_link_use_reserved_reassign(link);
1903 
1904 		return ieee80211_link_use_reserved_assign(link);
1905 	}
1906 
1907 	/*
1908 	 * In-place reservation may need to be finalized now either if:
1909 	 *  a) sdata is taking part in the swapping itself and is the last one
1910 	 *  b) sdata has switched with a re-assign reservation to an existing
1911 	 *     context readying in-place switching of old_ctx
1912 	 *
1913 	 * In case of (b) do not propagate the error up because the requested
1914 	 * sdata already switched successfully. Just spill an extra warning.
1915 	 * The ieee80211_vif_use_reserved_switch() already stops all necessary
1916 	 * interfaces upon failure.
1917 	 */
1918 	if ((old_ctx &&
1919 	     old_ctx->replace_state == IEEE80211_CHANCTX_WILL_BE_REPLACED) ||
1920 	    new_ctx->replace_state == IEEE80211_CHANCTX_REPLACES_OTHER) {
1921 		err = ieee80211_vif_use_reserved_switch(local);
1922 		if (err && err != -EAGAIN) {
1923 			if (new_ctx->replace_state ==
1924 			    IEEE80211_CHANCTX_REPLACES_OTHER)
1925 				return err;
1926 
1927 			wiphy_info(local->hw.wiphy,
1928 				   "depending in-place reservation failed (err=%d)\n",
1929 				   err);
1930 		}
1931 	}
1932 
1933 	return 0;
1934 }
1935 
1936 int ieee80211_link_change_bandwidth(struct ieee80211_link_data *link,
1937 				    const struct cfg80211_chan_def *chandef,
1938 				    u64 *changed)
1939 {
1940 	struct ieee80211_sub_if_data *sdata = link->sdata;
1941 	struct ieee80211_bss_conf *link_conf = link->conf;
1942 	struct ieee80211_local *local = sdata->local;
1943 	struct ieee80211_chanctx_conf *conf;
1944 	struct ieee80211_chanctx *ctx;
1945 	const struct cfg80211_chan_def *compat;
1946 	int ret;
1947 
1948 	if (!cfg80211_chandef_usable(sdata->local->hw.wiphy, chandef,
1949 				     IEEE80211_CHAN_DISABLED))
1950 		return -EINVAL;
1951 
1952 	mutex_lock(&local->chanctx_mtx);
1953 	if (cfg80211_chandef_identical(chandef, &link_conf->chandef)) {
1954 		ret = 0;
1955 		goto out;
1956 	}
1957 
1958 	if (chandef->width == NL80211_CHAN_WIDTH_20_NOHT ||
1959 	    link_conf->chandef.width == NL80211_CHAN_WIDTH_20_NOHT) {
1960 		ret = -EINVAL;
1961 		goto out;
1962 	}
1963 
1964 	conf = rcu_dereference_protected(link_conf->chanctx_conf,
1965 					 lockdep_is_held(&local->chanctx_mtx));
1966 	if (!conf) {
1967 		ret = -EINVAL;
1968 		goto out;
1969 	}
1970 
1971 	ctx = container_of(conf, struct ieee80211_chanctx, conf);
1972 
1973 	compat = cfg80211_chandef_compatible(&conf->def, chandef);
1974 	if (!compat) {
1975 		ret = -EINVAL;
1976 		goto out;
1977 	}
1978 
1979 	switch (ctx->replace_state) {
1980 	case IEEE80211_CHANCTX_REPLACE_NONE:
1981 		if (!ieee80211_chanctx_reserved_chandef(local, ctx, compat)) {
1982 			ret = -EBUSY;
1983 			goto out;
1984 		}
1985 		break;
1986 	case IEEE80211_CHANCTX_WILL_BE_REPLACED:
1987 		/* TODO: Perhaps the bandwidth change could be treated as a
1988 		 * reservation itself? */
1989 		ret = -EBUSY;
1990 		goto out;
1991 	case IEEE80211_CHANCTX_REPLACES_OTHER:
1992 		/* channel context that is going to replace another channel
1993 		 * context doesn't really exist and shouldn't be assigned
1994 		 * anywhere yet */
1995 		WARN_ON(1);
1996 		break;
1997 	}
1998 
1999 	ieee80211_link_update_chandef(link, chandef);
2000 
2001 	ieee80211_recalc_chanctx_chantype(local, ctx);
2002 
2003 	*changed |= BSS_CHANGED_BANDWIDTH;
2004 	ret = 0;
2005  out:
2006 	mutex_unlock(&local->chanctx_mtx);
2007 	return ret;
2008 }
2009 
2010 void ieee80211_link_release_channel(struct ieee80211_link_data *link)
2011 {
2012 	struct ieee80211_sub_if_data *sdata = link->sdata;
2013 
2014 	mutex_lock(&sdata->local->chanctx_mtx);
2015 	if (rcu_access_pointer(link->conf->chanctx_conf)) {
2016 		lockdep_assert_held(&sdata->local->mtx);
2017 		__ieee80211_link_release_channel(link);
2018 	}
2019 	mutex_unlock(&sdata->local->chanctx_mtx);
2020 }
2021 
2022 void ieee80211_link_vlan_copy_chanctx(struct ieee80211_link_data *link)
2023 {
2024 	struct ieee80211_sub_if_data *sdata = link->sdata;
2025 	unsigned int link_id = link->link_id;
2026 	struct ieee80211_bss_conf *link_conf = link->conf;
2027 	struct ieee80211_bss_conf *ap_conf;
2028 	struct ieee80211_local *local = sdata->local;
2029 	struct ieee80211_sub_if_data *ap;
2030 	struct ieee80211_chanctx_conf *conf;
2031 
2032 	if (WARN_ON(sdata->vif.type != NL80211_IFTYPE_AP_VLAN || !sdata->bss))
2033 		return;
2034 
2035 	ap = container_of(sdata->bss, struct ieee80211_sub_if_data, u.ap);
2036 
2037 	mutex_lock(&local->chanctx_mtx);
2038 
2039 	rcu_read_lock();
2040 	ap_conf = rcu_dereference(ap->vif.link_conf[link_id]);
2041 	conf = rcu_dereference_protected(ap_conf->chanctx_conf,
2042 					 lockdep_is_held(&local->chanctx_mtx));
2043 	rcu_assign_pointer(link_conf->chanctx_conf, conf);
2044 	rcu_read_unlock();
2045 	mutex_unlock(&local->chanctx_mtx);
2046 }
2047 
2048 void ieee80211_iter_chan_contexts_atomic(
2049 	struct ieee80211_hw *hw,
2050 	void (*iter)(struct ieee80211_hw *hw,
2051 		     struct ieee80211_chanctx_conf *chanctx_conf,
2052 		     void *data),
2053 	void *iter_data)
2054 {
2055 	struct ieee80211_local *local = hw_to_local(hw);
2056 	struct ieee80211_chanctx *ctx;
2057 
2058 	rcu_read_lock();
2059 	list_for_each_entry_rcu(ctx, &local->chanctx_list, list)
2060 		if (ctx->driver_present)
2061 			iter(hw, &ctx->conf, iter_data);
2062 	rcu_read_unlock();
2063 }
2064 EXPORT_SYMBOL_GPL(ieee80211_iter_chan_contexts_atomic);
2065