xref: /openbmc/linux/net/mac80211/chan.c (revision 83f865d7)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * mac80211 - channel management
4  */
5 
6 #include <linux/nl80211.h>
7 #include <linux/export.h>
8 #include <linux/rtnetlink.h>
9 #include <net/cfg80211.h>
10 #include "ieee80211_i.h"
11 #include "driver-ops.h"
12 
13 static int ieee80211_chanctx_num_assigned(struct ieee80211_local *local,
14 					  struct ieee80211_chanctx *ctx)
15 {
16 	struct ieee80211_sub_if_data *sdata;
17 	int num = 0;
18 
19 	lockdep_assert_held(&local->chanctx_mtx);
20 
21 	list_for_each_entry(sdata, &ctx->assigned_vifs, assigned_chanctx_list)
22 		num++;
23 
24 	return num;
25 }
26 
27 static int ieee80211_chanctx_num_reserved(struct ieee80211_local *local,
28 					  struct ieee80211_chanctx *ctx)
29 {
30 	struct ieee80211_sub_if_data *sdata;
31 	int num = 0;
32 
33 	lockdep_assert_held(&local->chanctx_mtx);
34 
35 	list_for_each_entry(sdata, &ctx->reserved_vifs, reserved_chanctx_list)
36 		num++;
37 
38 	return num;
39 }
40 
41 int ieee80211_chanctx_refcount(struct ieee80211_local *local,
42 			       struct ieee80211_chanctx *ctx)
43 {
44 	return ieee80211_chanctx_num_assigned(local, ctx) +
45 	       ieee80211_chanctx_num_reserved(local, ctx);
46 }
47 
48 static int ieee80211_num_chanctx(struct ieee80211_local *local)
49 {
50 	struct ieee80211_chanctx *ctx;
51 	int num = 0;
52 
53 	lockdep_assert_held(&local->chanctx_mtx);
54 
55 	list_for_each_entry(ctx, &local->chanctx_list, list)
56 		num++;
57 
58 	return num;
59 }
60 
61 static bool ieee80211_can_create_new_chanctx(struct ieee80211_local *local)
62 {
63 	lockdep_assert_held(&local->chanctx_mtx);
64 	return ieee80211_num_chanctx(local) < ieee80211_max_num_channels(local);
65 }
66 
67 static struct ieee80211_chanctx *
68 ieee80211_vif_get_chanctx(struct ieee80211_sub_if_data *sdata)
69 {
70 	struct ieee80211_local *local __maybe_unused = sdata->local;
71 	struct ieee80211_chanctx_conf *conf;
72 
73 	conf = rcu_dereference_protected(sdata->vif.chanctx_conf,
74 					 lockdep_is_held(&local->chanctx_mtx));
75 	if (!conf)
76 		return NULL;
77 
78 	return container_of(conf, struct ieee80211_chanctx, conf);
79 }
80 
81 static const struct cfg80211_chan_def *
82 ieee80211_chanctx_reserved_chandef(struct ieee80211_local *local,
83 				   struct ieee80211_chanctx *ctx,
84 				   const struct cfg80211_chan_def *compat)
85 {
86 	struct ieee80211_sub_if_data *sdata;
87 
88 	lockdep_assert_held(&local->chanctx_mtx);
89 
90 	list_for_each_entry(sdata, &ctx->reserved_vifs,
91 			    reserved_chanctx_list) {
92 		if (!compat)
93 			compat = &sdata->reserved_chandef;
94 
95 		compat = cfg80211_chandef_compatible(&sdata->reserved_chandef,
96 						     compat);
97 		if (!compat)
98 			break;
99 	}
100 
101 	return compat;
102 }
103 
104 static const struct cfg80211_chan_def *
105 ieee80211_chanctx_non_reserved_chandef(struct ieee80211_local *local,
106 				       struct ieee80211_chanctx *ctx,
107 				       const struct cfg80211_chan_def *compat)
108 {
109 	struct ieee80211_sub_if_data *sdata;
110 
111 	lockdep_assert_held(&local->chanctx_mtx);
112 
113 	list_for_each_entry(sdata, &ctx->assigned_vifs,
114 			    assigned_chanctx_list) {
115 		if (sdata->reserved_chanctx != NULL)
116 			continue;
117 
118 		if (!compat)
119 			compat = &sdata->vif.bss_conf.chandef;
120 
121 		compat = cfg80211_chandef_compatible(
122 				&sdata->vif.bss_conf.chandef, compat);
123 		if (!compat)
124 			break;
125 	}
126 
127 	return compat;
128 }
129 
130 static const struct cfg80211_chan_def *
131 ieee80211_chanctx_combined_chandef(struct ieee80211_local *local,
132 				   struct ieee80211_chanctx *ctx,
133 				   const struct cfg80211_chan_def *compat)
134 {
135 	lockdep_assert_held(&local->chanctx_mtx);
136 
137 	compat = ieee80211_chanctx_reserved_chandef(local, ctx, compat);
138 	if (!compat)
139 		return NULL;
140 
141 	compat = ieee80211_chanctx_non_reserved_chandef(local, ctx, compat);
142 	if (!compat)
143 		return NULL;
144 
145 	return compat;
146 }
147 
148 static bool
149 ieee80211_chanctx_can_reserve_chandef(struct ieee80211_local *local,
150 				      struct ieee80211_chanctx *ctx,
151 				      const struct cfg80211_chan_def *def)
152 {
153 	lockdep_assert_held(&local->chanctx_mtx);
154 
155 	if (ieee80211_chanctx_combined_chandef(local, ctx, def))
156 		return true;
157 
158 	if (!list_empty(&ctx->reserved_vifs) &&
159 	    ieee80211_chanctx_reserved_chandef(local, ctx, def))
160 		return true;
161 
162 	return false;
163 }
164 
165 static struct ieee80211_chanctx *
166 ieee80211_find_reservation_chanctx(struct ieee80211_local *local,
167 				   const struct cfg80211_chan_def *chandef,
168 				   enum ieee80211_chanctx_mode mode)
169 {
170 	struct ieee80211_chanctx *ctx;
171 
172 	lockdep_assert_held(&local->chanctx_mtx);
173 
174 	if (mode == IEEE80211_CHANCTX_EXCLUSIVE)
175 		return NULL;
176 
177 	list_for_each_entry(ctx, &local->chanctx_list, list) {
178 		if (ctx->replace_state == IEEE80211_CHANCTX_WILL_BE_REPLACED)
179 			continue;
180 
181 		if (ctx->mode == IEEE80211_CHANCTX_EXCLUSIVE)
182 			continue;
183 
184 		if (!ieee80211_chanctx_can_reserve_chandef(local, ctx,
185 							   chandef))
186 			continue;
187 
188 		return ctx;
189 	}
190 
191 	return NULL;
192 }
193 
194 enum nl80211_chan_width ieee80211_get_sta_bw(struct ieee80211_sta *sta)
195 {
196 	switch (sta->bandwidth) {
197 	case IEEE80211_STA_RX_BW_20:
198 		if (sta->ht_cap.ht_supported)
199 			return NL80211_CHAN_WIDTH_20;
200 		else
201 			return NL80211_CHAN_WIDTH_20_NOHT;
202 	case IEEE80211_STA_RX_BW_40:
203 		return NL80211_CHAN_WIDTH_40;
204 	case IEEE80211_STA_RX_BW_80:
205 		return NL80211_CHAN_WIDTH_80;
206 	case IEEE80211_STA_RX_BW_160:
207 		/*
208 		 * This applied for both 160 and 80+80. since we use
209 		 * the returned value to consider degradation of
210 		 * ctx->conf.min_def, we have to make sure to take
211 		 * the bigger one (NL80211_CHAN_WIDTH_160).
212 		 * Otherwise we might try degrading even when not
213 		 * needed, as the max required sta_bw returned (80+80)
214 		 * might be smaller than the configured bw (160).
215 		 */
216 		return NL80211_CHAN_WIDTH_160;
217 	default:
218 		WARN_ON(1);
219 		return NL80211_CHAN_WIDTH_20;
220 	}
221 }
222 
223 static enum nl80211_chan_width
224 ieee80211_get_max_required_bw(struct ieee80211_sub_if_data *sdata)
225 {
226 	enum nl80211_chan_width max_bw = NL80211_CHAN_WIDTH_20_NOHT;
227 	struct sta_info *sta;
228 
229 	rcu_read_lock();
230 	list_for_each_entry_rcu(sta, &sdata->local->sta_list, list) {
231 		if (sdata != sta->sdata &&
232 		    !(sta->sdata->bss && sta->sdata->bss == sdata->bss))
233 			continue;
234 
235 		max_bw = max(max_bw, ieee80211_get_sta_bw(&sta->sta));
236 	}
237 	rcu_read_unlock();
238 
239 	return max_bw;
240 }
241 
242 static enum nl80211_chan_width
243 ieee80211_get_chanctx_max_required_bw(struct ieee80211_local *local,
244 				      struct ieee80211_chanctx_conf *conf)
245 {
246 	struct ieee80211_sub_if_data *sdata;
247 	enum nl80211_chan_width max_bw = NL80211_CHAN_WIDTH_20_NOHT;
248 
249 	rcu_read_lock();
250 	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
251 		struct ieee80211_vif *vif = &sdata->vif;
252 		enum nl80211_chan_width width = NL80211_CHAN_WIDTH_20_NOHT;
253 
254 		if (!ieee80211_sdata_running(sdata))
255 			continue;
256 
257 		if (rcu_access_pointer(sdata->vif.chanctx_conf) != conf)
258 			continue;
259 
260 		switch (vif->type) {
261 		case NL80211_IFTYPE_AP:
262 		case NL80211_IFTYPE_AP_VLAN:
263 			width = ieee80211_get_max_required_bw(sdata);
264 			break;
265 		case NL80211_IFTYPE_STATION:
266 			/*
267 			 * The ap's sta->bandwidth is not set yet at this
268 			 * point, so take the width from the chandef, but
269 			 * account also for TDLS peers
270 			 */
271 			width = max(vif->bss_conf.chandef.width,
272 				    ieee80211_get_max_required_bw(sdata));
273 			break;
274 		case NL80211_IFTYPE_P2P_DEVICE:
275 		case NL80211_IFTYPE_NAN:
276 			continue;
277 		case NL80211_IFTYPE_ADHOC:
278 		case NL80211_IFTYPE_WDS:
279 		case NL80211_IFTYPE_MESH_POINT:
280 		case NL80211_IFTYPE_OCB:
281 			width = vif->bss_conf.chandef.width;
282 			break;
283 		case NL80211_IFTYPE_UNSPECIFIED:
284 		case NUM_NL80211_IFTYPES:
285 		case NL80211_IFTYPE_MONITOR:
286 		case NL80211_IFTYPE_P2P_CLIENT:
287 		case NL80211_IFTYPE_P2P_GO:
288 			WARN_ON_ONCE(1);
289 		}
290 		max_bw = max(max_bw, width);
291 	}
292 
293 	/* use the configured bandwidth in case of monitor interface */
294 	sdata = rcu_dereference(local->monitor_sdata);
295 	if (sdata && rcu_access_pointer(sdata->vif.chanctx_conf) == conf)
296 		max_bw = max(max_bw, conf->def.width);
297 
298 	rcu_read_unlock();
299 
300 	return max_bw;
301 }
302 
303 /*
304  * recalc the min required chan width of the channel context, which is
305  * the max of min required widths of all the interfaces bound to this
306  * channel context.
307  */
308 void ieee80211_recalc_chanctx_min_def(struct ieee80211_local *local,
309 				      struct ieee80211_chanctx *ctx)
310 {
311 	enum nl80211_chan_width max_bw;
312 	struct cfg80211_chan_def min_def;
313 
314 	lockdep_assert_held(&local->chanctx_mtx);
315 
316 	/* don't optimize non-20MHz based and radar_enabled confs */
317 	if (ctx->conf.def.width == NL80211_CHAN_WIDTH_5 ||
318 	    ctx->conf.def.width == NL80211_CHAN_WIDTH_10 ||
319 	    ctx->conf.def.width == NL80211_CHAN_WIDTH_1 ||
320 	    ctx->conf.def.width == NL80211_CHAN_WIDTH_2 ||
321 	    ctx->conf.def.width == NL80211_CHAN_WIDTH_4 ||
322 	    ctx->conf.def.width == NL80211_CHAN_WIDTH_8 ||
323 	    ctx->conf.def.width == NL80211_CHAN_WIDTH_16 ||
324 	    ctx->conf.radar_enabled) {
325 		ctx->conf.min_def = ctx->conf.def;
326 		return;
327 	}
328 
329 	max_bw = ieee80211_get_chanctx_max_required_bw(local, &ctx->conf);
330 
331 	/* downgrade chandef up to max_bw */
332 	min_def = ctx->conf.def;
333 	while (min_def.width > max_bw)
334 		ieee80211_chandef_downgrade(&min_def);
335 
336 	if (cfg80211_chandef_identical(&ctx->conf.min_def, &min_def))
337 		return;
338 
339 	ctx->conf.min_def = min_def;
340 	if (!ctx->driver_present)
341 		return;
342 
343 	drv_change_chanctx(local, ctx, IEEE80211_CHANCTX_CHANGE_MIN_WIDTH);
344 }
345 
346 static void ieee80211_change_chanctx(struct ieee80211_local *local,
347 				     struct ieee80211_chanctx *ctx,
348 				     const struct cfg80211_chan_def *chandef)
349 {
350 	if (cfg80211_chandef_identical(&ctx->conf.def, chandef)) {
351 		ieee80211_recalc_chanctx_min_def(local, ctx);
352 		return;
353 	}
354 
355 	WARN_ON(!cfg80211_chandef_compatible(&ctx->conf.def, chandef));
356 
357 	ctx->conf.def = *chandef;
358 	drv_change_chanctx(local, ctx, IEEE80211_CHANCTX_CHANGE_WIDTH);
359 	ieee80211_recalc_chanctx_min_def(local, ctx);
360 
361 	if (!local->use_chanctx) {
362 		local->_oper_chandef = *chandef;
363 		ieee80211_hw_config(local, 0);
364 	}
365 }
366 
367 static struct ieee80211_chanctx *
368 ieee80211_find_chanctx(struct ieee80211_local *local,
369 		       const struct cfg80211_chan_def *chandef,
370 		       enum ieee80211_chanctx_mode mode)
371 {
372 	struct ieee80211_chanctx *ctx;
373 
374 	lockdep_assert_held(&local->chanctx_mtx);
375 
376 	if (mode == IEEE80211_CHANCTX_EXCLUSIVE)
377 		return NULL;
378 
379 	list_for_each_entry(ctx, &local->chanctx_list, list) {
380 		const struct cfg80211_chan_def *compat;
381 
382 		if (ctx->replace_state != IEEE80211_CHANCTX_REPLACE_NONE)
383 			continue;
384 
385 		if (ctx->mode == IEEE80211_CHANCTX_EXCLUSIVE)
386 			continue;
387 
388 		compat = cfg80211_chandef_compatible(&ctx->conf.def, chandef);
389 		if (!compat)
390 			continue;
391 
392 		compat = ieee80211_chanctx_reserved_chandef(local, ctx,
393 							    compat);
394 		if (!compat)
395 			continue;
396 
397 		ieee80211_change_chanctx(local, ctx, compat);
398 
399 		return ctx;
400 	}
401 
402 	return NULL;
403 }
404 
405 bool ieee80211_is_radar_required(struct ieee80211_local *local)
406 {
407 	struct ieee80211_sub_if_data *sdata;
408 
409 	lockdep_assert_held(&local->mtx);
410 
411 	rcu_read_lock();
412 	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
413 		if (sdata->radar_required) {
414 			rcu_read_unlock();
415 			return true;
416 		}
417 	}
418 	rcu_read_unlock();
419 
420 	return false;
421 }
422 
423 static bool
424 ieee80211_chanctx_radar_required(struct ieee80211_local *local,
425 				 struct ieee80211_chanctx *ctx)
426 {
427 	struct ieee80211_chanctx_conf *conf = &ctx->conf;
428 	struct ieee80211_sub_if_data *sdata;
429 	bool required = false;
430 
431 	lockdep_assert_held(&local->chanctx_mtx);
432 	lockdep_assert_held(&local->mtx);
433 
434 	rcu_read_lock();
435 	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
436 		if (!ieee80211_sdata_running(sdata))
437 			continue;
438 		if (rcu_access_pointer(sdata->vif.chanctx_conf) != conf)
439 			continue;
440 		if (!sdata->radar_required)
441 			continue;
442 
443 		required = true;
444 		break;
445 	}
446 	rcu_read_unlock();
447 
448 	return required;
449 }
450 
451 static struct ieee80211_chanctx *
452 ieee80211_alloc_chanctx(struct ieee80211_local *local,
453 			const struct cfg80211_chan_def *chandef,
454 			enum ieee80211_chanctx_mode mode)
455 {
456 	struct ieee80211_chanctx *ctx;
457 
458 	lockdep_assert_held(&local->chanctx_mtx);
459 
460 	ctx = kzalloc(sizeof(*ctx) + local->hw.chanctx_data_size, GFP_KERNEL);
461 	if (!ctx)
462 		return NULL;
463 
464 	INIT_LIST_HEAD(&ctx->assigned_vifs);
465 	INIT_LIST_HEAD(&ctx->reserved_vifs);
466 	ctx->conf.def = *chandef;
467 	ctx->conf.rx_chains_static = 1;
468 	ctx->conf.rx_chains_dynamic = 1;
469 	ctx->mode = mode;
470 	ctx->conf.radar_enabled = false;
471 	ieee80211_recalc_chanctx_min_def(local, ctx);
472 
473 	return ctx;
474 }
475 
476 static int ieee80211_add_chanctx(struct ieee80211_local *local,
477 				 struct ieee80211_chanctx *ctx)
478 {
479 	u32 changed;
480 	int err;
481 
482 	lockdep_assert_held(&local->mtx);
483 	lockdep_assert_held(&local->chanctx_mtx);
484 
485 	if (!local->use_chanctx)
486 		local->hw.conf.radar_enabled = ctx->conf.radar_enabled;
487 
488 	/* turn idle off *before* setting channel -- some drivers need that */
489 	changed = ieee80211_idle_off(local);
490 	if (changed)
491 		ieee80211_hw_config(local, changed);
492 
493 	if (!local->use_chanctx) {
494 		local->_oper_chandef = ctx->conf.def;
495 		ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
496 	} else {
497 		err = drv_add_chanctx(local, ctx);
498 		if (err) {
499 			ieee80211_recalc_idle(local);
500 			return err;
501 		}
502 	}
503 
504 	return 0;
505 }
506 
507 static struct ieee80211_chanctx *
508 ieee80211_new_chanctx(struct ieee80211_local *local,
509 		      const struct cfg80211_chan_def *chandef,
510 		      enum ieee80211_chanctx_mode mode)
511 {
512 	struct ieee80211_chanctx *ctx;
513 	int err;
514 
515 	lockdep_assert_held(&local->mtx);
516 	lockdep_assert_held(&local->chanctx_mtx);
517 
518 	ctx = ieee80211_alloc_chanctx(local, chandef, mode);
519 	if (!ctx)
520 		return ERR_PTR(-ENOMEM);
521 
522 	err = ieee80211_add_chanctx(local, ctx);
523 	if (err) {
524 		kfree(ctx);
525 		return ERR_PTR(err);
526 	}
527 
528 	list_add_rcu(&ctx->list, &local->chanctx_list);
529 	return ctx;
530 }
531 
532 static void ieee80211_del_chanctx(struct ieee80211_local *local,
533 				  struct ieee80211_chanctx *ctx)
534 {
535 	lockdep_assert_held(&local->chanctx_mtx);
536 
537 	if (!local->use_chanctx) {
538 		struct cfg80211_chan_def *chandef = &local->_oper_chandef;
539 		/* S1G doesn't have 20MHz, so get the correct width for the
540 		 * current channel.
541 		 */
542 		if (chandef->chan->band == NL80211_BAND_S1GHZ)
543 			chandef->width =
544 				ieee80211_s1g_channel_width(chandef->chan);
545 		else
546 			chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
547 		chandef->center_freq1 = chandef->chan->center_freq;
548 		chandef->freq1_offset = chandef->chan->freq_offset;
549 		chandef->center_freq2 = 0;
550 
551 		/* NOTE: Disabling radar is only valid here for
552 		 * single channel context. To be sure, check it ...
553 		 */
554 		WARN_ON(local->hw.conf.radar_enabled &&
555 			!list_empty(&local->chanctx_list));
556 
557 		local->hw.conf.radar_enabled = false;
558 
559 		ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
560 	} else {
561 		drv_remove_chanctx(local, ctx);
562 	}
563 
564 	ieee80211_recalc_idle(local);
565 }
566 
567 static void ieee80211_free_chanctx(struct ieee80211_local *local,
568 				   struct ieee80211_chanctx *ctx)
569 {
570 	lockdep_assert_held(&local->chanctx_mtx);
571 
572 	WARN_ON_ONCE(ieee80211_chanctx_refcount(local, ctx) != 0);
573 
574 	list_del_rcu(&ctx->list);
575 	ieee80211_del_chanctx(local, ctx);
576 	kfree_rcu(ctx, rcu_head);
577 }
578 
579 void ieee80211_recalc_chanctx_chantype(struct ieee80211_local *local,
580 				       struct ieee80211_chanctx *ctx)
581 {
582 	struct ieee80211_chanctx_conf *conf = &ctx->conf;
583 	struct ieee80211_sub_if_data *sdata;
584 	const struct cfg80211_chan_def *compat = NULL;
585 	struct sta_info *sta;
586 
587 	lockdep_assert_held(&local->chanctx_mtx);
588 
589 	rcu_read_lock();
590 	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
591 
592 		if (!ieee80211_sdata_running(sdata))
593 			continue;
594 		if (rcu_access_pointer(sdata->vif.chanctx_conf) != conf)
595 			continue;
596 		if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
597 			continue;
598 
599 		if (!compat)
600 			compat = &sdata->vif.bss_conf.chandef;
601 
602 		compat = cfg80211_chandef_compatible(
603 				&sdata->vif.bss_conf.chandef, compat);
604 		if (WARN_ON_ONCE(!compat))
605 			break;
606 	}
607 
608 	/* TDLS peers can sometimes affect the chandef width */
609 	list_for_each_entry_rcu(sta, &local->sta_list, list) {
610 		if (!sta->uploaded ||
611 		    !test_sta_flag(sta, WLAN_STA_TDLS_WIDER_BW) ||
612 		    !test_sta_flag(sta, WLAN_STA_AUTHORIZED) ||
613 		    !sta->tdls_chandef.chan)
614 			continue;
615 
616 		compat = cfg80211_chandef_compatible(&sta->tdls_chandef,
617 						     compat);
618 		if (WARN_ON_ONCE(!compat))
619 			break;
620 	}
621 	rcu_read_unlock();
622 
623 	if (!compat)
624 		return;
625 
626 	ieee80211_change_chanctx(local, ctx, compat);
627 }
628 
629 static void ieee80211_recalc_radar_chanctx(struct ieee80211_local *local,
630 					   struct ieee80211_chanctx *chanctx)
631 {
632 	bool radar_enabled;
633 
634 	lockdep_assert_held(&local->chanctx_mtx);
635 	/* for ieee80211_is_radar_required */
636 	lockdep_assert_held(&local->mtx);
637 
638 	radar_enabled = ieee80211_chanctx_radar_required(local, chanctx);
639 
640 	if (radar_enabled == chanctx->conf.radar_enabled)
641 		return;
642 
643 	chanctx->conf.radar_enabled = radar_enabled;
644 
645 	if (!local->use_chanctx) {
646 		local->hw.conf.radar_enabled = chanctx->conf.radar_enabled;
647 		ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
648 	}
649 
650 	drv_change_chanctx(local, chanctx, IEEE80211_CHANCTX_CHANGE_RADAR);
651 }
652 
653 static int ieee80211_assign_vif_chanctx(struct ieee80211_sub_if_data *sdata,
654 					struct ieee80211_chanctx *new_ctx)
655 {
656 	struct ieee80211_local *local = sdata->local;
657 	struct ieee80211_chanctx_conf *conf;
658 	struct ieee80211_chanctx *curr_ctx = NULL;
659 	int ret = 0;
660 
661 	if (WARN_ON(sdata->vif.type == NL80211_IFTYPE_NAN))
662 		return -ENOTSUPP;
663 
664 	conf = rcu_dereference_protected(sdata->vif.chanctx_conf,
665 					 lockdep_is_held(&local->chanctx_mtx));
666 
667 	if (conf) {
668 		curr_ctx = container_of(conf, struct ieee80211_chanctx, conf);
669 
670 		drv_unassign_vif_chanctx(local, sdata, curr_ctx);
671 		conf = NULL;
672 		list_del(&sdata->assigned_chanctx_list);
673 	}
674 
675 	if (new_ctx) {
676 		ret = drv_assign_vif_chanctx(local, sdata, new_ctx);
677 		if (ret)
678 			goto out;
679 
680 		conf = &new_ctx->conf;
681 		list_add(&sdata->assigned_chanctx_list,
682 			 &new_ctx->assigned_vifs);
683 	}
684 
685 out:
686 	rcu_assign_pointer(sdata->vif.chanctx_conf, conf);
687 
688 	sdata->vif.bss_conf.idle = !conf;
689 
690 	if (curr_ctx && ieee80211_chanctx_num_assigned(local, curr_ctx) > 0) {
691 		ieee80211_recalc_chanctx_chantype(local, curr_ctx);
692 		ieee80211_recalc_smps_chanctx(local, curr_ctx);
693 		ieee80211_recalc_radar_chanctx(local, curr_ctx);
694 		ieee80211_recalc_chanctx_min_def(local, curr_ctx);
695 	}
696 
697 	if (new_ctx && ieee80211_chanctx_num_assigned(local, new_ctx) > 0) {
698 		ieee80211_recalc_txpower(sdata, false);
699 		ieee80211_recalc_chanctx_min_def(local, new_ctx);
700 	}
701 
702 	if (sdata->vif.type != NL80211_IFTYPE_P2P_DEVICE &&
703 	    sdata->vif.type != NL80211_IFTYPE_MONITOR)
704 		ieee80211_bss_info_change_notify(sdata,
705 						 BSS_CHANGED_IDLE);
706 
707 	ieee80211_check_fast_xmit_iface(sdata);
708 
709 	return ret;
710 }
711 
712 void ieee80211_recalc_smps_chanctx(struct ieee80211_local *local,
713 				   struct ieee80211_chanctx *chanctx)
714 {
715 	struct ieee80211_sub_if_data *sdata;
716 	u8 rx_chains_static, rx_chains_dynamic;
717 
718 	lockdep_assert_held(&local->chanctx_mtx);
719 
720 	rx_chains_static = 1;
721 	rx_chains_dynamic = 1;
722 
723 	rcu_read_lock();
724 	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
725 		u8 needed_static, needed_dynamic;
726 
727 		if (!ieee80211_sdata_running(sdata))
728 			continue;
729 
730 		if (rcu_access_pointer(sdata->vif.chanctx_conf) !=
731 						&chanctx->conf)
732 			continue;
733 
734 		switch (sdata->vif.type) {
735 		case NL80211_IFTYPE_P2P_DEVICE:
736 		case NL80211_IFTYPE_NAN:
737 			continue;
738 		case NL80211_IFTYPE_STATION:
739 			if (!sdata->u.mgd.associated)
740 				continue;
741 			break;
742 		case NL80211_IFTYPE_AP_VLAN:
743 			continue;
744 		case NL80211_IFTYPE_AP:
745 		case NL80211_IFTYPE_ADHOC:
746 		case NL80211_IFTYPE_WDS:
747 		case NL80211_IFTYPE_MESH_POINT:
748 		case NL80211_IFTYPE_OCB:
749 			break;
750 		default:
751 			WARN_ON_ONCE(1);
752 		}
753 
754 		switch (sdata->smps_mode) {
755 		default:
756 			WARN_ONCE(1, "Invalid SMPS mode %d\n",
757 				  sdata->smps_mode);
758 			fallthrough;
759 		case IEEE80211_SMPS_OFF:
760 			needed_static = sdata->needed_rx_chains;
761 			needed_dynamic = sdata->needed_rx_chains;
762 			break;
763 		case IEEE80211_SMPS_DYNAMIC:
764 			needed_static = 1;
765 			needed_dynamic = sdata->needed_rx_chains;
766 			break;
767 		case IEEE80211_SMPS_STATIC:
768 			needed_static = 1;
769 			needed_dynamic = 1;
770 			break;
771 		}
772 
773 		rx_chains_static = max(rx_chains_static, needed_static);
774 		rx_chains_dynamic = max(rx_chains_dynamic, needed_dynamic);
775 	}
776 
777 	/* Disable SMPS for the monitor interface */
778 	sdata = rcu_dereference(local->monitor_sdata);
779 	if (sdata &&
780 	    rcu_access_pointer(sdata->vif.chanctx_conf) == &chanctx->conf)
781 		rx_chains_dynamic = rx_chains_static = local->rx_chains;
782 
783 	rcu_read_unlock();
784 
785 	if (!local->use_chanctx) {
786 		if (rx_chains_static > 1)
787 			local->smps_mode = IEEE80211_SMPS_OFF;
788 		else if (rx_chains_dynamic > 1)
789 			local->smps_mode = IEEE80211_SMPS_DYNAMIC;
790 		else
791 			local->smps_mode = IEEE80211_SMPS_STATIC;
792 		ieee80211_hw_config(local, 0);
793 	}
794 
795 	if (rx_chains_static == chanctx->conf.rx_chains_static &&
796 	    rx_chains_dynamic == chanctx->conf.rx_chains_dynamic)
797 		return;
798 
799 	chanctx->conf.rx_chains_static = rx_chains_static;
800 	chanctx->conf.rx_chains_dynamic = rx_chains_dynamic;
801 	drv_change_chanctx(local, chanctx, IEEE80211_CHANCTX_CHANGE_RX_CHAINS);
802 }
803 
804 static void
805 __ieee80211_vif_copy_chanctx_to_vlans(struct ieee80211_sub_if_data *sdata,
806 				      bool clear)
807 {
808 	struct ieee80211_local *local __maybe_unused = sdata->local;
809 	struct ieee80211_sub_if_data *vlan;
810 	struct ieee80211_chanctx_conf *conf;
811 
812 	if (WARN_ON(sdata->vif.type != NL80211_IFTYPE_AP))
813 		return;
814 
815 	lockdep_assert_held(&local->mtx);
816 
817 	/* Check that conf exists, even when clearing this function
818 	 * must be called with the AP's channel context still there
819 	 * as it would otherwise cause VLANs to have an invalid
820 	 * channel context pointer for a while, possibly pointing
821 	 * to a channel context that has already been freed.
822 	 */
823 	conf = rcu_dereference_protected(sdata->vif.chanctx_conf,
824 					 lockdep_is_held(&local->chanctx_mtx));
825 	WARN_ON(!conf);
826 
827 	if (clear)
828 		conf = NULL;
829 
830 	list_for_each_entry(vlan, &sdata->u.ap.vlans, u.vlan.list)
831 		rcu_assign_pointer(vlan->vif.chanctx_conf, conf);
832 }
833 
834 void ieee80211_vif_copy_chanctx_to_vlans(struct ieee80211_sub_if_data *sdata,
835 					 bool clear)
836 {
837 	struct ieee80211_local *local = sdata->local;
838 
839 	mutex_lock(&local->chanctx_mtx);
840 
841 	__ieee80211_vif_copy_chanctx_to_vlans(sdata, clear);
842 
843 	mutex_unlock(&local->chanctx_mtx);
844 }
845 
846 int ieee80211_vif_unreserve_chanctx(struct ieee80211_sub_if_data *sdata)
847 {
848 	struct ieee80211_chanctx *ctx = sdata->reserved_chanctx;
849 
850 	lockdep_assert_held(&sdata->local->chanctx_mtx);
851 
852 	if (WARN_ON(!ctx))
853 		return -EINVAL;
854 
855 	list_del(&sdata->reserved_chanctx_list);
856 	sdata->reserved_chanctx = NULL;
857 
858 	if (ieee80211_chanctx_refcount(sdata->local, ctx) == 0) {
859 		if (ctx->replace_state == IEEE80211_CHANCTX_REPLACES_OTHER) {
860 			if (WARN_ON(!ctx->replace_ctx))
861 				return -EINVAL;
862 
863 			WARN_ON(ctx->replace_ctx->replace_state !=
864 			        IEEE80211_CHANCTX_WILL_BE_REPLACED);
865 			WARN_ON(ctx->replace_ctx->replace_ctx != ctx);
866 
867 			ctx->replace_ctx->replace_ctx = NULL;
868 			ctx->replace_ctx->replace_state =
869 					IEEE80211_CHANCTX_REPLACE_NONE;
870 
871 			list_del_rcu(&ctx->list);
872 			kfree_rcu(ctx, rcu_head);
873 		} else {
874 			ieee80211_free_chanctx(sdata->local, ctx);
875 		}
876 	}
877 
878 	return 0;
879 }
880 
881 int ieee80211_vif_reserve_chanctx(struct ieee80211_sub_if_data *sdata,
882 				  const struct cfg80211_chan_def *chandef,
883 				  enum ieee80211_chanctx_mode mode,
884 				  bool radar_required)
885 {
886 	struct ieee80211_local *local = sdata->local;
887 	struct ieee80211_chanctx *new_ctx, *curr_ctx, *ctx;
888 
889 	lockdep_assert_held(&local->chanctx_mtx);
890 
891 	curr_ctx = ieee80211_vif_get_chanctx(sdata);
892 	if (curr_ctx && local->use_chanctx && !local->ops->switch_vif_chanctx)
893 		return -ENOTSUPP;
894 
895 	new_ctx = ieee80211_find_reservation_chanctx(local, chandef, mode);
896 	if (!new_ctx) {
897 		if (ieee80211_can_create_new_chanctx(local)) {
898 			new_ctx = ieee80211_new_chanctx(local, chandef, mode);
899 			if (IS_ERR(new_ctx))
900 				return PTR_ERR(new_ctx);
901 		} else {
902 			if (!curr_ctx ||
903 			    (curr_ctx->replace_state ==
904 			     IEEE80211_CHANCTX_WILL_BE_REPLACED) ||
905 			    !list_empty(&curr_ctx->reserved_vifs)) {
906 				/*
907 				 * Another vif already requested this context
908 				 * for a reservation. Find another one hoping
909 				 * all vifs assigned to it will also switch
910 				 * soon enough.
911 				 *
912 				 * TODO: This needs a little more work as some
913 				 * cases (more than 2 chanctx capable devices)
914 				 * may fail which could otherwise succeed
915 				 * provided some channel context juggling was
916 				 * performed.
917 				 *
918 				 * Consider ctx1..3, vif1..6, each ctx has 2
919 				 * vifs. vif1 and vif2 from ctx1 request new
920 				 * different chandefs starting 2 in-place
921 				 * reserations with ctx4 and ctx5 replacing
922 				 * ctx1 and ctx2 respectively. Next vif5 and
923 				 * vif6 from ctx3 reserve ctx4. If vif3 and
924 				 * vif4 remain on ctx2 as they are then this
925 				 * fails unless `replace_ctx` from ctx5 is
926 				 * replaced with ctx3.
927 				 */
928 				list_for_each_entry(ctx, &local->chanctx_list,
929 						    list) {
930 					if (ctx->replace_state !=
931 					    IEEE80211_CHANCTX_REPLACE_NONE)
932 						continue;
933 
934 					if (!list_empty(&ctx->reserved_vifs))
935 						continue;
936 
937 					curr_ctx = ctx;
938 					break;
939 				}
940 			}
941 
942 			/*
943 			 * If that's true then all available contexts already
944 			 * have reservations and cannot be used.
945 			 */
946 			if (!curr_ctx ||
947 			    (curr_ctx->replace_state ==
948 			     IEEE80211_CHANCTX_WILL_BE_REPLACED) ||
949 			    !list_empty(&curr_ctx->reserved_vifs))
950 				return -EBUSY;
951 
952 			new_ctx = ieee80211_alloc_chanctx(local, chandef, mode);
953 			if (!new_ctx)
954 				return -ENOMEM;
955 
956 			new_ctx->replace_ctx = curr_ctx;
957 			new_ctx->replace_state =
958 					IEEE80211_CHANCTX_REPLACES_OTHER;
959 
960 			curr_ctx->replace_ctx = new_ctx;
961 			curr_ctx->replace_state =
962 					IEEE80211_CHANCTX_WILL_BE_REPLACED;
963 
964 			list_add_rcu(&new_ctx->list, &local->chanctx_list);
965 		}
966 	}
967 
968 	list_add(&sdata->reserved_chanctx_list, &new_ctx->reserved_vifs);
969 	sdata->reserved_chanctx = new_ctx;
970 	sdata->reserved_chandef = *chandef;
971 	sdata->reserved_radar_required = radar_required;
972 	sdata->reserved_ready = false;
973 
974 	return 0;
975 }
976 
977 static void
978 ieee80211_vif_chanctx_reservation_complete(struct ieee80211_sub_if_data *sdata)
979 {
980 	switch (sdata->vif.type) {
981 	case NL80211_IFTYPE_ADHOC:
982 	case NL80211_IFTYPE_AP:
983 	case NL80211_IFTYPE_MESH_POINT:
984 	case NL80211_IFTYPE_OCB:
985 		ieee80211_queue_work(&sdata->local->hw,
986 				     &sdata->csa_finalize_work);
987 		break;
988 	case NL80211_IFTYPE_STATION:
989 		ieee80211_queue_work(&sdata->local->hw,
990 				     &sdata->u.mgd.chswitch_work);
991 		break;
992 	case NL80211_IFTYPE_UNSPECIFIED:
993 	case NL80211_IFTYPE_AP_VLAN:
994 	case NL80211_IFTYPE_WDS:
995 	case NL80211_IFTYPE_MONITOR:
996 	case NL80211_IFTYPE_P2P_CLIENT:
997 	case NL80211_IFTYPE_P2P_GO:
998 	case NL80211_IFTYPE_P2P_DEVICE:
999 	case NL80211_IFTYPE_NAN:
1000 	case NUM_NL80211_IFTYPES:
1001 		WARN_ON(1);
1002 		break;
1003 	}
1004 }
1005 
1006 static void
1007 ieee80211_vif_update_chandef(struct ieee80211_sub_if_data *sdata,
1008 			     const struct cfg80211_chan_def *chandef)
1009 {
1010 	struct ieee80211_sub_if_data *vlan;
1011 
1012 	sdata->vif.bss_conf.chandef = *chandef;
1013 
1014 	if (sdata->vif.type != NL80211_IFTYPE_AP)
1015 		return;
1016 
1017 	list_for_each_entry(vlan, &sdata->u.ap.vlans, u.vlan.list)
1018 		vlan->vif.bss_conf.chandef = *chandef;
1019 }
1020 
1021 static int
1022 ieee80211_vif_use_reserved_reassign(struct ieee80211_sub_if_data *sdata)
1023 {
1024 	struct ieee80211_local *local = sdata->local;
1025 	struct ieee80211_vif_chanctx_switch vif_chsw[1] = {};
1026 	struct ieee80211_chanctx *old_ctx, *new_ctx;
1027 	const struct cfg80211_chan_def *chandef;
1028 	u32 changed = 0;
1029 	int err;
1030 
1031 	lockdep_assert_held(&local->mtx);
1032 	lockdep_assert_held(&local->chanctx_mtx);
1033 
1034 	new_ctx = sdata->reserved_chanctx;
1035 	old_ctx = ieee80211_vif_get_chanctx(sdata);
1036 
1037 	if (WARN_ON(!sdata->reserved_ready))
1038 		return -EBUSY;
1039 
1040 	if (WARN_ON(!new_ctx))
1041 		return -EINVAL;
1042 
1043 	if (WARN_ON(!old_ctx))
1044 		return -EINVAL;
1045 
1046 	if (WARN_ON(new_ctx->replace_state ==
1047 		    IEEE80211_CHANCTX_REPLACES_OTHER))
1048 		return -EINVAL;
1049 
1050 	chandef = ieee80211_chanctx_non_reserved_chandef(local, new_ctx,
1051 				&sdata->reserved_chandef);
1052 	if (WARN_ON(!chandef))
1053 		return -EINVAL;
1054 
1055 	ieee80211_change_chanctx(local, new_ctx, chandef);
1056 
1057 	vif_chsw[0].vif = &sdata->vif;
1058 	vif_chsw[0].old_ctx = &old_ctx->conf;
1059 	vif_chsw[0].new_ctx = &new_ctx->conf;
1060 
1061 	list_del(&sdata->reserved_chanctx_list);
1062 	sdata->reserved_chanctx = NULL;
1063 
1064 	err = drv_switch_vif_chanctx(local, vif_chsw, 1,
1065 				     CHANCTX_SWMODE_REASSIGN_VIF);
1066 	if (err) {
1067 		if (ieee80211_chanctx_refcount(local, new_ctx) == 0)
1068 			ieee80211_free_chanctx(local, new_ctx);
1069 
1070 		goto out;
1071 	}
1072 
1073 	list_move(&sdata->assigned_chanctx_list, &new_ctx->assigned_vifs);
1074 	rcu_assign_pointer(sdata->vif.chanctx_conf, &new_ctx->conf);
1075 
1076 	if (sdata->vif.type == NL80211_IFTYPE_AP)
1077 		__ieee80211_vif_copy_chanctx_to_vlans(sdata, false);
1078 
1079 	ieee80211_check_fast_xmit_iface(sdata);
1080 
1081 	if (ieee80211_chanctx_refcount(local, old_ctx) == 0)
1082 		ieee80211_free_chanctx(local, old_ctx);
1083 
1084 	if (sdata->vif.bss_conf.chandef.width != sdata->reserved_chandef.width)
1085 		changed = BSS_CHANGED_BANDWIDTH;
1086 
1087 	ieee80211_vif_update_chandef(sdata, &sdata->reserved_chandef);
1088 
1089 	ieee80211_recalc_smps_chanctx(local, new_ctx);
1090 	ieee80211_recalc_radar_chanctx(local, new_ctx);
1091 	ieee80211_recalc_chanctx_min_def(local, new_ctx);
1092 
1093 	if (changed)
1094 		ieee80211_bss_info_change_notify(sdata, changed);
1095 
1096 out:
1097 	ieee80211_vif_chanctx_reservation_complete(sdata);
1098 	return err;
1099 }
1100 
1101 static int
1102 ieee80211_vif_use_reserved_assign(struct ieee80211_sub_if_data *sdata)
1103 {
1104 	struct ieee80211_local *local = sdata->local;
1105 	struct ieee80211_chanctx *old_ctx, *new_ctx;
1106 	const struct cfg80211_chan_def *chandef;
1107 	int err;
1108 
1109 	old_ctx = ieee80211_vif_get_chanctx(sdata);
1110 	new_ctx = sdata->reserved_chanctx;
1111 
1112 	if (WARN_ON(!sdata->reserved_ready))
1113 		return -EINVAL;
1114 
1115 	if (WARN_ON(old_ctx))
1116 		return -EINVAL;
1117 
1118 	if (WARN_ON(!new_ctx))
1119 		return -EINVAL;
1120 
1121 	if (WARN_ON(new_ctx->replace_state ==
1122 		    IEEE80211_CHANCTX_REPLACES_OTHER))
1123 		return -EINVAL;
1124 
1125 	chandef = ieee80211_chanctx_non_reserved_chandef(local, new_ctx,
1126 				&sdata->reserved_chandef);
1127 	if (WARN_ON(!chandef))
1128 		return -EINVAL;
1129 
1130 	ieee80211_change_chanctx(local, new_ctx, chandef);
1131 
1132 	list_del(&sdata->reserved_chanctx_list);
1133 	sdata->reserved_chanctx = NULL;
1134 
1135 	err = ieee80211_assign_vif_chanctx(sdata, new_ctx);
1136 	if (err) {
1137 		if (ieee80211_chanctx_refcount(local, new_ctx) == 0)
1138 			ieee80211_free_chanctx(local, new_ctx);
1139 
1140 		goto out;
1141 	}
1142 
1143 out:
1144 	ieee80211_vif_chanctx_reservation_complete(sdata);
1145 	return err;
1146 }
1147 
1148 static bool
1149 ieee80211_vif_has_in_place_reservation(struct ieee80211_sub_if_data *sdata)
1150 {
1151 	struct ieee80211_chanctx *old_ctx, *new_ctx;
1152 
1153 	lockdep_assert_held(&sdata->local->chanctx_mtx);
1154 
1155 	new_ctx = sdata->reserved_chanctx;
1156 	old_ctx = ieee80211_vif_get_chanctx(sdata);
1157 
1158 	if (!old_ctx)
1159 		return false;
1160 
1161 	if (WARN_ON(!new_ctx))
1162 		return false;
1163 
1164 	if (old_ctx->replace_state != IEEE80211_CHANCTX_WILL_BE_REPLACED)
1165 		return false;
1166 
1167 	if (new_ctx->replace_state != IEEE80211_CHANCTX_REPLACES_OTHER)
1168 		return false;
1169 
1170 	return true;
1171 }
1172 
1173 static int ieee80211_chsw_switch_hwconf(struct ieee80211_local *local,
1174 					struct ieee80211_chanctx *new_ctx)
1175 {
1176 	const struct cfg80211_chan_def *chandef;
1177 
1178 	lockdep_assert_held(&local->mtx);
1179 	lockdep_assert_held(&local->chanctx_mtx);
1180 
1181 	chandef = ieee80211_chanctx_reserved_chandef(local, new_ctx, NULL);
1182 	if (WARN_ON(!chandef))
1183 		return -EINVAL;
1184 
1185 	local->hw.conf.radar_enabled = new_ctx->conf.radar_enabled;
1186 	local->_oper_chandef = *chandef;
1187 	ieee80211_hw_config(local, 0);
1188 
1189 	return 0;
1190 }
1191 
1192 static int ieee80211_chsw_switch_vifs(struct ieee80211_local *local,
1193 				      int n_vifs)
1194 {
1195 	struct ieee80211_vif_chanctx_switch *vif_chsw;
1196 	struct ieee80211_sub_if_data *sdata;
1197 	struct ieee80211_chanctx *ctx, *old_ctx;
1198 	int i, err;
1199 
1200 	lockdep_assert_held(&local->mtx);
1201 	lockdep_assert_held(&local->chanctx_mtx);
1202 
1203 	vif_chsw = kcalloc(n_vifs, sizeof(vif_chsw[0]), GFP_KERNEL);
1204 	if (!vif_chsw)
1205 		return -ENOMEM;
1206 
1207 	i = 0;
1208 	list_for_each_entry(ctx, &local->chanctx_list, list) {
1209 		if (ctx->replace_state != IEEE80211_CHANCTX_REPLACES_OTHER)
1210 			continue;
1211 
1212 		if (WARN_ON(!ctx->replace_ctx)) {
1213 			err = -EINVAL;
1214 			goto out;
1215 		}
1216 
1217 		list_for_each_entry(sdata, &ctx->reserved_vifs,
1218 				    reserved_chanctx_list) {
1219 			if (!ieee80211_vif_has_in_place_reservation(
1220 					sdata))
1221 				continue;
1222 
1223 			old_ctx = ieee80211_vif_get_chanctx(sdata);
1224 			vif_chsw[i].vif = &sdata->vif;
1225 			vif_chsw[i].old_ctx = &old_ctx->conf;
1226 			vif_chsw[i].new_ctx = &ctx->conf;
1227 
1228 			i++;
1229 		}
1230 	}
1231 
1232 	err = drv_switch_vif_chanctx(local, vif_chsw, n_vifs,
1233 				     CHANCTX_SWMODE_SWAP_CONTEXTS);
1234 
1235 out:
1236 	kfree(vif_chsw);
1237 	return err;
1238 }
1239 
1240 static int ieee80211_chsw_switch_ctxs(struct ieee80211_local *local)
1241 {
1242 	struct ieee80211_chanctx *ctx;
1243 	int err;
1244 
1245 	lockdep_assert_held(&local->mtx);
1246 	lockdep_assert_held(&local->chanctx_mtx);
1247 
1248 	list_for_each_entry(ctx, &local->chanctx_list, list) {
1249 		if (ctx->replace_state != IEEE80211_CHANCTX_REPLACES_OTHER)
1250 			continue;
1251 
1252 		if (!list_empty(&ctx->replace_ctx->assigned_vifs))
1253 			continue;
1254 
1255 		ieee80211_del_chanctx(local, ctx->replace_ctx);
1256 		err = ieee80211_add_chanctx(local, ctx);
1257 		if (err)
1258 			goto err;
1259 	}
1260 
1261 	return 0;
1262 
1263 err:
1264 	WARN_ON(ieee80211_add_chanctx(local, ctx));
1265 	list_for_each_entry_continue_reverse(ctx, &local->chanctx_list, list) {
1266 		if (ctx->replace_state != IEEE80211_CHANCTX_REPLACES_OTHER)
1267 			continue;
1268 
1269 		if (!list_empty(&ctx->replace_ctx->assigned_vifs))
1270 			continue;
1271 
1272 		ieee80211_del_chanctx(local, ctx);
1273 		WARN_ON(ieee80211_add_chanctx(local, ctx->replace_ctx));
1274 	}
1275 
1276 	return err;
1277 }
1278 
1279 static int ieee80211_vif_use_reserved_switch(struct ieee80211_local *local)
1280 {
1281 	struct ieee80211_sub_if_data *sdata, *sdata_tmp;
1282 	struct ieee80211_chanctx *ctx, *ctx_tmp, *old_ctx;
1283 	struct ieee80211_chanctx *new_ctx = NULL;
1284 	int err, n_assigned, n_reserved, n_ready;
1285 	int n_ctx = 0, n_vifs_switch = 0, n_vifs_assign = 0, n_vifs_ctxless = 0;
1286 
1287 	lockdep_assert_held(&local->mtx);
1288 	lockdep_assert_held(&local->chanctx_mtx);
1289 
1290 	/*
1291 	 * If there are 2 independent pairs of channel contexts performing
1292 	 * cross-switch of their vifs this code will still wait until both are
1293 	 * ready even though it could be possible to switch one before the
1294 	 * other is ready.
1295 	 *
1296 	 * For practical reasons and code simplicity just do a single huge
1297 	 * switch.
1298 	 */
1299 
1300 	/*
1301 	 * Verify if the reservation is still feasible.
1302 	 *  - if it's not then disconnect
1303 	 *  - if it is but not all vifs necessary are ready then defer
1304 	 */
1305 
1306 	list_for_each_entry(ctx, &local->chanctx_list, list) {
1307 		if (ctx->replace_state != IEEE80211_CHANCTX_REPLACES_OTHER)
1308 			continue;
1309 
1310 		if (WARN_ON(!ctx->replace_ctx)) {
1311 			err = -EINVAL;
1312 			goto err;
1313 		}
1314 
1315 		if (!local->use_chanctx)
1316 			new_ctx = ctx;
1317 
1318 		n_ctx++;
1319 
1320 		n_assigned = 0;
1321 		n_reserved = 0;
1322 		n_ready = 0;
1323 
1324 		list_for_each_entry(sdata, &ctx->replace_ctx->assigned_vifs,
1325 				    assigned_chanctx_list) {
1326 			n_assigned++;
1327 			if (sdata->reserved_chanctx) {
1328 				n_reserved++;
1329 				if (sdata->reserved_ready)
1330 					n_ready++;
1331 			}
1332 		}
1333 
1334 		if (n_assigned != n_reserved) {
1335 			if (n_ready == n_reserved) {
1336 				wiphy_info(local->hw.wiphy,
1337 					   "channel context reservation cannot be finalized because some interfaces aren't switching\n");
1338 				err = -EBUSY;
1339 				goto err;
1340 			}
1341 
1342 			return -EAGAIN;
1343 		}
1344 
1345 		ctx->conf.radar_enabled = false;
1346 		list_for_each_entry(sdata, &ctx->reserved_vifs,
1347 				    reserved_chanctx_list) {
1348 			if (ieee80211_vif_has_in_place_reservation(sdata) &&
1349 			    !sdata->reserved_ready)
1350 				return -EAGAIN;
1351 
1352 			old_ctx = ieee80211_vif_get_chanctx(sdata);
1353 			if (old_ctx) {
1354 				if (old_ctx->replace_state ==
1355 				    IEEE80211_CHANCTX_WILL_BE_REPLACED)
1356 					n_vifs_switch++;
1357 				else
1358 					n_vifs_assign++;
1359 			} else {
1360 				n_vifs_ctxless++;
1361 			}
1362 
1363 			if (sdata->reserved_radar_required)
1364 				ctx->conf.radar_enabled = true;
1365 		}
1366 	}
1367 
1368 	if (WARN_ON(n_ctx == 0) ||
1369 	    WARN_ON(n_vifs_switch == 0 &&
1370 		    n_vifs_assign == 0 &&
1371 		    n_vifs_ctxless == 0) ||
1372 	    WARN_ON(n_ctx > 1 && !local->use_chanctx) ||
1373 	    WARN_ON(!new_ctx && !local->use_chanctx)) {
1374 		err = -EINVAL;
1375 		goto err;
1376 	}
1377 
1378 	/*
1379 	 * All necessary vifs are ready. Perform the switch now depending on
1380 	 * reservations and driver capabilities.
1381 	 */
1382 
1383 	if (local->use_chanctx) {
1384 		if (n_vifs_switch > 0) {
1385 			err = ieee80211_chsw_switch_vifs(local, n_vifs_switch);
1386 			if (err)
1387 				goto err;
1388 		}
1389 
1390 		if (n_vifs_assign > 0 || n_vifs_ctxless > 0) {
1391 			err = ieee80211_chsw_switch_ctxs(local);
1392 			if (err)
1393 				goto err;
1394 		}
1395 	} else {
1396 		err = ieee80211_chsw_switch_hwconf(local, new_ctx);
1397 		if (err)
1398 			goto err;
1399 	}
1400 
1401 	/*
1402 	 * Update all structures, values and pointers to point to new channel
1403 	 * context(s).
1404 	 */
1405 	list_for_each_entry(ctx, &local->chanctx_list, list) {
1406 		if (ctx->replace_state != IEEE80211_CHANCTX_REPLACES_OTHER)
1407 			continue;
1408 
1409 		if (WARN_ON(!ctx->replace_ctx)) {
1410 			err = -EINVAL;
1411 			goto err;
1412 		}
1413 
1414 		list_for_each_entry(sdata, &ctx->reserved_vifs,
1415 				    reserved_chanctx_list) {
1416 			u32 changed = 0;
1417 
1418 			if (!ieee80211_vif_has_in_place_reservation(sdata))
1419 				continue;
1420 
1421 			rcu_assign_pointer(sdata->vif.chanctx_conf, &ctx->conf);
1422 
1423 			if (sdata->vif.type == NL80211_IFTYPE_AP)
1424 				__ieee80211_vif_copy_chanctx_to_vlans(sdata,
1425 								      false);
1426 
1427 			ieee80211_check_fast_xmit_iface(sdata);
1428 
1429 			sdata->radar_required = sdata->reserved_radar_required;
1430 
1431 			if (sdata->vif.bss_conf.chandef.width !=
1432 			    sdata->reserved_chandef.width)
1433 				changed = BSS_CHANGED_BANDWIDTH;
1434 
1435 			ieee80211_vif_update_chandef(sdata, &sdata->reserved_chandef);
1436 			if (changed)
1437 				ieee80211_bss_info_change_notify(sdata,
1438 								 changed);
1439 
1440 			ieee80211_recalc_txpower(sdata, false);
1441 		}
1442 
1443 		ieee80211_recalc_chanctx_chantype(local, ctx);
1444 		ieee80211_recalc_smps_chanctx(local, ctx);
1445 		ieee80211_recalc_radar_chanctx(local, ctx);
1446 		ieee80211_recalc_chanctx_min_def(local, ctx);
1447 
1448 		list_for_each_entry_safe(sdata, sdata_tmp, &ctx->reserved_vifs,
1449 					 reserved_chanctx_list) {
1450 			if (ieee80211_vif_get_chanctx(sdata) != ctx)
1451 				continue;
1452 
1453 			list_del(&sdata->reserved_chanctx_list);
1454 			list_move(&sdata->assigned_chanctx_list,
1455 				  &ctx->assigned_vifs);
1456 			sdata->reserved_chanctx = NULL;
1457 
1458 			ieee80211_vif_chanctx_reservation_complete(sdata);
1459 		}
1460 
1461 		/*
1462 		 * This context might have been a dependency for an already
1463 		 * ready re-assign reservation interface that was deferred. Do
1464 		 * not propagate error to the caller though. The in-place
1465 		 * reservation for originally requested interface has already
1466 		 * succeeded at this point.
1467 		 */
1468 		list_for_each_entry_safe(sdata, sdata_tmp, &ctx->reserved_vifs,
1469 					 reserved_chanctx_list) {
1470 			if (WARN_ON(ieee80211_vif_has_in_place_reservation(
1471 					sdata)))
1472 				continue;
1473 
1474 			if (WARN_ON(sdata->reserved_chanctx != ctx))
1475 				continue;
1476 
1477 			if (!sdata->reserved_ready)
1478 				continue;
1479 
1480 			if (ieee80211_vif_get_chanctx(sdata))
1481 				err = ieee80211_vif_use_reserved_reassign(
1482 						sdata);
1483 			else
1484 				err = ieee80211_vif_use_reserved_assign(sdata);
1485 
1486 			if (err) {
1487 				sdata_info(sdata,
1488 					   "failed to finalize (re-)assign reservation (err=%d)\n",
1489 					   err);
1490 				ieee80211_vif_unreserve_chanctx(sdata);
1491 				cfg80211_stop_iface(local->hw.wiphy,
1492 						    &sdata->wdev,
1493 						    GFP_KERNEL);
1494 			}
1495 		}
1496 	}
1497 
1498 	/*
1499 	 * Finally free old contexts
1500 	 */
1501 
1502 	list_for_each_entry_safe(ctx, ctx_tmp, &local->chanctx_list, list) {
1503 		if (ctx->replace_state != IEEE80211_CHANCTX_WILL_BE_REPLACED)
1504 			continue;
1505 
1506 		ctx->replace_ctx->replace_ctx = NULL;
1507 		ctx->replace_ctx->replace_state =
1508 				IEEE80211_CHANCTX_REPLACE_NONE;
1509 
1510 		list_del_rcu(&ctx->list);
1511 		kfree_rcu(ctx, rcu_head);
1512 	}
1513 
1514 	return 0;
1515 
1516 err:
1517 	list_for_each_entry(ctx, &local->chanctx_list, list) {
1518 		if (ctx->replace_state != IEEE80211_CHANCTX_REPLACES_OTHER)
1519 			continue;
1520 
1521 		list_for_each_entry_safe(sdata, sdata_tmp, &ctx->reserved_vifs,
1522 					 reserved_chanctx_list) {
1523 			ieee80211_vif_unreserve_chanctx(sdata);
1524 			ieee80211_vif_chanctx_reservation_complete(sdata);
1525 		}
1526 	}
1527 
1528 	return err;
1529 }
1530 
1531 static void __ieee80211_vif_release_channel(struct ieee80211_sub_if_data *sdata)
1532 {
1533 	struct ieee80211_local *local = sdata->local;
1534 	struct ieee80211_chanctx_conf *conf;
1535 	struct ieee80211_chanctx *ctx;
1536 	bool use_reserved_switch = false;
1537 
1538 	lockdep_assert_held(&local->chanctx_mtx);
1539 
1540 	conf = rcu_dereference_protected(sdata->vif.chanctx_conf,
1541 					 lockdep_is_held(&local->chanctx_mtx));
1542 	if (!conf)
1543 		return;
1544 
1545 	ctx = container_of(conf, struct ieee80211_chanctx, conf);
1546 
1547 	if (sdata->reserved_chanctx) {
1548 		if (sdata->reserved_chanctx->replace_state ==
1549 		    IEEE80211_CHANCTX_REPLACES_OTHER &&
1550 		    ieee80211_chanctx_num_reserved(local,
1551 						   sdata->reserved_chanctx) > 1)
1552 			use_reserved_switch = true;
1553 
1554 		ieee80211_vif_unreserve_chanctx(sdata);
1555 	}
1556 
1557 	ieee80211_assign_vif_chanctx(sdata, NULL);
1558 	if (ieee80211_chanctx_refcount(local, ctx) == 0)
1559 		ieee80211_free_chanctx(local, ctx);
1560 
1561 	sdata->radar_required = false;
1562 
1563 	/* Unreserving may ready an in-place reservation. */
1564 	if (use_reserved_switch)
1565 		ieee80211_vif_use_reserved_switch(local);
1566 }
1567 
1568 int ieee80211_vif_use_channel(struct ieee80211_sub_if_data *sdata,
1569 			      const struct cfg80211_chan_def *chandef,
1570 			      enum ieee80211_chanctx_mode mode)
1571 {
1572 	struct ieee80211_local *local = sdata->local;
1573 	struct ieee80211_chanctx *ctx;
1574 	u8 radar_detect_width = 0;
1575 	int ret;
1576 
1577 	lockdep_assert_held(&local->mtx);
1578 
1579 	WARN_ON(sdata->dev && netif_carrier_ok(sdata->dev));
1580 
1581 	mutex_lock(&local->chanctx_mtx);
1582 
1583 	ret = cfg80211_chandef_dfs_required(local->hw.wiphy,
1584 					    chandef,
1585 					    sdata->wdev.iftype);
1586 	if (ret < 0)
1587 		goto out;
1588 	if (ret > 0)
1589 		radar_detect_width = BIT(chandef->width);
1590 
1591 	sdata->radar_required = ret;
1592 
1593 	ret = ieee80211_check_combinations(sdata, chandef, mode,
1594 					   radar_detect_width);
1595 	if (ret < 0)
1596 		goto out;
1597 
1598 	__ieee80211_vif_release_channel(sdata);
1599 
1600 	ctx = ieee80211_find_chanctx(local, chandef, mode);
1601 	if (!ctx)
1602 		ctx = ieee80211_new_chanctx(local, chandef, mode);
1603 	if (IS_ERR(ctx)) {
1604 		ret = PTR_ERR(ctx);
1605 		goto out;
1606 	}
1607 
1608 	ieee80211_vif_update_chandef(sdata, chandef);
1609 
1610 	ret = ieee80211_assign_vif_chanctx(sdata, ctx);
1611 	if (ret) {
1612 		/* if assign fails refcount stays the same */
1613 		if (ieee80211_chanctx_refcount(local, ctx) == 0)
1614 			ieee80211_free_chanctx(local, ctx);
1615 		goto out;
1616 	}
1617 
1618 	ieee80211_recalc_smps_chanctx(local, ctx);
1619 	ieee80211_recalc_radar_chanctx(local, ctx);
1620  out:
1621 	if (ret)
1622 		sdata->radar_required = false;
1623 
1624 	mutex_unlock(&local->chanctx_mtx);
1625 	return ret;
1626 }
1627 
1628 int ieee80211_vif_use_reserved_context(struct ieee80211_sub_if_data *sdata)
1629 {
1630 	struct ieee80211_local *local = sdata->local;
1631 	struct ieee80211_chanctx *new_ctx;
1632 	struct ieee80211_chanctx *old_ctx;
1633 	int err;
1634 
1635 	lockdep_assert_held(&local->mtx);
1636 	lockdep_assert_held(&local->chanctx_mtx);
1637 
1638 	new_ctx = sdata->reserved_chanctx;
1639 	old_ctx = ieee80211_vif_get_chanctx(sdata);
1640 
1641 	if (WARN_ON(!new_ctx))
1642 		return -EINVAL;
1643 
1644 	if (WARN_ON(new_ctx->replace_state ==
1645 		    IEEE80211_CHANCTX_WILL_BE_REPLACED))
1646 		return -EINVAL;
1647 
1648 	if (WARN_ON(sdata->reserved_ready))
1649 		return -EINVAL;
1650 
1651 	sdata->reserved_ready = true;
1652 
1653 	if (new_ctx->replace_state == IEEE80211_CHANCTX_REPLACE_NONE) {
1654 		if (old_ctx)
1655 			err = ieee80211_vif_use_reserved_reassign(sdata);
1656 		else
1657 			err = ieee80211_vif_use_reserved_assign(sdata);
1658 
1659 		if (err)
1660 			return err;
1661 	}
1662 
1663 	/*
1664 	 * In-place reservation may need to be finalized now either if:
1665 	 *  a) sdata is taking part in the swapping itself and is the last one
1666 	 *  b) sdata has switched with a re-assign reservation to an existing
1667 	 *     context readying in-place switching of old_ctx
1668 	 *
1669 	 * In case of (b) do not propagate the error up because the requested
1670 	 * sdata already switched successfully. Just spill an extra warning.
1671 	 * The ieee80211_vif_use_reserved_switch() already stops all necessary
1672 	 * interfaces upon failure.
1673 	 */
1674 	if ((old_ctx &&
1675 	     old_ctx->replace_state == IEEE80211_CHANCTX_WILL_BE_REPLACED) ||
1676 	    new_ctx->replace_state == IEEE80211_CHANCTX_REPLACES_OTHER) {
1677 		err = ieee80211_vif_use_reserved_switch(local);
1678 		if (err && err != -EAGAIN) {
1679 			if (new_ctx->replace_state ==
1680 			    IEEE80211_CHANCTX_REPLACES_OTHER)
1681 				return err;
1682 
1683 			wiphy_info(local->hw.wiphy,
1684 				   "depending in-place reservation failed (err=%d)\n",
1685 				   err);
1686 		}
1687 	}
1688 
1689 	return 0;
1690 }
1691 
1692 int ieee80211_vif_change_bandwidth(struct ieee80211_sub_if_data *sdata,
1693 				   const struct cfg80211_chan_def *chandef,
1694 				   u32 *changed)
1695 {
1696 	struct ieee80211_local *local = sdata->local;
1697 	struct ieee80211_chanctx_conf *conf;
1698 	struct ieee80211_chanctx *ctx;
1699 	const struct cfg80211_chan_def *compat;
1700 	int ret;
1701 
1702 	if (!cfg80211_chandef_usable(sdata->local->hw.wiphy, chandef,
1703 				     IEEE80211_CHAN_DISABLED))
1704 		return -EINVAL;
1705 
1706 	mutex_lock(&local->chanctx_mtx);
1707 	if (cfg80211_chandef_identical(chandef, &sdata->vif.bss_conf.chandef)) {
1708 		ret = 0;
1709 		goto out;
1710 	}
1711 
1712 	if (chandef->width == NL80211_CHAN_WIDTH_20_NOHT ||
1713 	    sdata->vif.bss_conf.chandef.width == NL80211_CHAN_WIDTH_20_NOHT) {
1714 		ret = -EINVAL;
1715 		goto out;
1716 	}
1717 
1718 	conf = rcu_dereference_protected(sdata->vif.chanctx_conf,
1719 					 lockdep_is_held(&local->chanctx_mtx));
1720 	if (!conf) {
1721 		ret = -EINVAL;
1722 		goto out;
1723 	}
1724 
1725 	ctx = container_of(conf, struct ieee80211_chanctx, conf);
1726 
1727 	compat = cfg80211_chandef_compatible(&conf->def, chandef);
1728 	if (!compat) {
1729 		ret = -EINVAL;
1730 		goto out;
1731 	}
1732 
1733 	switch (ctx->replace_state) {
1734 	case IEEE80211_CHANCTX_REPLACE_NONE:
1735 		if (!ieee80211_chanctx_reserved_chandef(local, ctx, compat)) {
1736 			ret = -EBUSY;
1737 			goto out;
1738 		}
1739 		break;
1740 	case IEEE80211_CHANCTX_WILL_BE_REPLACED:
1741 		/* TODO: Perhaps the bandwidth change could be treated as a
1742 		 * reservation itself? */
1743 		ret = -EBUSY;
1744 		goto out;
1745 	case IEEE80211_CHANCTX_REPLACES_OTHER:
1746 		/* channel context that is going to replace another channel
1747 		 * context doesn't really exist and shouldn't be assigned
1748 		 * anywhere yet */
1749 		WARN_ON(1);
1750 		break;
1751 	}
1752 
1753 	ieee80211_vif_update_chandef(sdata, chandef);
1754 
1755 	ieee80211_recalc_chanctx_chantype(local, ctx);
1756 
1757 	*changed |= BSS_CHANGED_BANDWIDTH;
1758 	ret = 0;
1759  out:
1760 	mutex_unlock(&local->chanctx_mtx);
1761 	return ret;
1762 }
1763 
1764 void ieee80211_vif_release_channel(struct ieee80211_sub_if_data *sdata)
1765 {
1766 	WARN_ON(sdata->dev && netif_carrier_ok(sdata->dev));
1767 
1768 	lockdep_assert_held(&sdata->local->mtx);
1769 
1770 	mutex_lock(&sdata->local->chanctx_mtx);
1771 	__ieee80211_vif_release_channel(sdata);
1772 	mutex_unlock(&sdata->local->chanctx_mtx);
1773 }
1774 
1775 void ieee80211_vif_vlan_copy_chanctx(struct ieee80211_sub_if_data *sdata)
1776 {
1777 	struct ieee80211_local *local = sdata->local;
1778 	struct ieee80211_sub_if_data *ap;
1779 	struct ieee80211_chanctx_conf *conf;
1780 
1781 	if (WARN_ON(sdata->vif.type != NL80211_IFTYPE_AP_VLAN || !sdata->bss))
1782 		return;
1783 
1784 	ap = container_of(sdata->bss, struct ieee80211_sub_if_data, u.ap);
1785 
1786 	mutex_lock(&local->chanctx_mtx);
1787 
1788 	conf = rcu_dereference_protected(ap->vif.chanctx_conf,
1789 					 lockdep_is_held(&local->chanctx_mtx));
1790 	rcu_assign_pointer(sdata->vif.chanctx_conf, conf);
1791 	mutex_unlock(&local->chanctx_mtx);
1792 }
1793 
1794 void ieee80211_iter_chan_contexts_atomic(
1795 	struct ieee80211_hw *hw,
1796 	void (*iter)(struct ieee80211_hw *hw,
1797 		     struct ieee80211_chanctx_conf *chanctx_conf,
1798 		     void *data),
1799 	void *iter_data)
1800 {
1801 	struct ieee80211_local *local = hw_to_local(hw);
1802 	struct ieee80211_chanctx *ctx;
1803 
1804 	rcu_read_lock();
1805 	list_for_each_entry_rcu(ctx, &local->chanctx_list, list)
1806 		if (ctx->driver_present)
1807 			iter(hw, &ctx->conf, iter_data);
1808 	rcu_read_unlock();
1809 }
1810 EXPORT_SYMBOL_GPL(ieee80211_iter_chan_contexts_atomic);
1811