wifi: mac80211: RCU-ify link/link_conf pointers

Since links can be added and removed dynamically, we need to
somehow protect the sdata->link[] and vif->link_conf[] array
pointers from disappearing when accessing them without locks.
RCU-ify the pointers to achieve this, which requires quite a
bit of rework.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

22 files changed, 420 insertions, 275 deletions

diff --git a/drivers/net/wireless/mac80211_hwsim.c b/drivers/net/wireless/mac80211_hwsim.c
index 4f22f3df161c..6bad95eeb709 100644
--- a/drivers/net/wireless/mac80211_hwsim.c
+++ b/drivers/net/wireless/mac80211_hwsim.c
@@ -1477,9 +1477,10 @@ static void mac80211_hwsim_tx_iter(void *_data, u8 *addr,
 	int i;
 
 	for (i = 0; i < ARRAY_SIZE(vif->link_conf); i++) {
-		struct ieee80211_bss_conf *conf = vif->link_conf[i];
+		struct ieee80211_bss_conf *conf;
 		struct ieee80211_chanctx_conf *chanctx;
 
+		conf = rcu_dereference(vif->link_conf[i]);
 		if (!conf)
 			continue;
 
@@ -1917,7 +1918,7 @@ static void mac80211_hwsim_beacon_tx(void *arg, u8 *mac,
 {
 	struct mac80211_hwsim_link_data *link_data = arg;
 	u32 link_id = link_data->link_id;
-	struct ieee80211_bss_conf *link_conf = vif->link_conf[link_id];
+	struct ieee80211_bss_conf *link_conf;
 	struct mac80211_hwsim_data *data =
 		container_of(link_data, struct mac80211_hwsim_data,
 			     link_data[link_id]);
@@ -1931,6 +1932,10 @@ static void mac80211_hwsim_beacon_tx(void *arg, u8 *mac,
 
 	hwsim_check_magic(vif);
 
+	link_conf = rcu_dereference(vif->link_conf[link_id]);
+	if (!link_conf)
+		return;
+
 	if (vif->type != NL80211_IFTYPE_AP &&
 	    vif->type != NL80211_IFTYPE_MESH_POINT &&
 	    vif->type != NL80211_IFTYPE_ADHOC &&
@@ -2155,12 +2160,11 @@ static void mac80211_hwsim_vif_info_changed(struct ieee80211_hw *hw,
 
 static void mac80211_hwsim_link_info_changed(struct ieee80211_hw *hw,
 					     struct ieee80211_vif *vif,
-					     u32 link_id,
-					     u64 changed)
+					     struct ieee80211_bss_conf *info,
+					     u32 link_id, u64 changed)
 {
 	struct hwsim_vif_priv *vp = (void *)vif->drv_priv;
 	struct mac80211_hwsim_data *data = hw->priv;
-	struct ieee80211_bss_conf *info = vif->link_conf[link_id];
 	struct mac80211_hwsim_link_data *link_data = &data->link_data[link_id];
 
 	hwsim_check_magic(vif);
diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 1c005a30313f..044ed417b06f 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -1789,7 +1789,7 @@ struct ieee80211_vif {
 	enum nl80211_iftype type;
 	struct ieee80211_vif_cfg cfg;
 	struct ieee80211_bss_conf bss_conf;
-	struct ieee80211_bss_conf *link_conf[IEEE80211_MLD_MAX_NUM_LINKS];
+	struct ieee80211_bss_conf __rcu *link_conf[IEEE80211_MLD_MAX_NUM_LINKS];
 	u16 valid_links;
 	u8 addr[ETH_ALEN] __aligned(2);
 	bool p2p;
@@ -4082,7 +4082,9 @@ struct ieee80211_ops {
 				u64 changed);
 	void (*link_info_changed)(struct ieee80211_hw *hw,
 				  struct ieee80211_vif *vif,
-				  unsigned int link_id, u64 changed);
+				  struct ieee80211_bss_conf *info,
+				  unsigned int link_id,
+				  u64 changed);
 
 	int (*start_ap)(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
 			unsigned int link_id);
diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index 85032dcaa595..3d66e40af7a9 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -39,7 +39,7 @@ static void ieee80211_set_mu_mimo_follow(struct ieee80211_sub_if_data *sdata,
 		memcpy(sdata->vif.bss_conf.mu_group.position,
 		       params->vht_mumimo_groups + WLAN_MEMBERSHIP_LEN,
 		       WLAN_USER_POSITION_LEN);
-		ieee80211_link_info_change_notify(sdata, 0,
+		ieee80211_link_info_change_notify(sdata, &sdata->deflink,
 						  BSS_CHANGED_MU_GROUPS);
 		/* don't care about endianness - just check for 0 */
 		memcpy(&membership, params->vht_mumimo_groups,
@@ -841,8 +841,8 @@ static int ieee80211_set_monitor_channel(struct wiphy *wiphy,
 		sdata = wiphy_dereference(local->hw.wiphy,
 					  local->monitor_sdata);
 		if (sdata) {
-			ieee80211_link_release_channel(sdata->link[0]);
-			ret = ieee80211_link_use_channel(sdata->link[0],
+			ieee80211_link_release_channel(&sdata->deflink);
+			ret = ieee80211_link_use_channel(&sdata->deflink,
 							 chandef,
 							 IEEE80211_CHANCTX_EXCLUSIVE);
 		}
@@ -1008,6 +1008,7 @@ ieee80211_copy_mbssid_beacon(u8 *pos, struct cfg80211_mbssid_elems *dst,
 }
 
 static int ieee80211_assign_beacon(struct ieee80211_sub_if_data *sdata,
+				   struct ieee80211_link_data *link,
 				   struct cfg80211_beacon_data *params,
 				   const struct ieee80211_csa_settings *csa,
 				   const struct ieee80211_color_change_settings *cca)
@@ -1017,9 +1018,7 @@ static int ieee80211_assign_beacon(struct ieee80211_sub_if_data *sdata,
 	int new_head_len, new_tail_len;
 	int size, err;
 	u32 changed = BSS_CHANGED_BEACON;
-	struct ieee80211_link_data *link = sdata->link[params->link_id];
-	struct ieee80211_bss_conf *link_conf =
-		sdata->vif.link_conf[params->link_id];
+	struct ieee80211_bss_conf *link_conf = link->conf;
 
 	old = sdata_dereference(link->u.ap.beacon, sdata);
 
@@ -1153,8 +1152,14 @@ static int ieee80211_start_ap(struct wiphy *wiphy, struct net_device *dev,
 	int i, err;
 	int prev_beacon_int;
 	unsigned int link_id = params->beacon.link_id;
-	struct ieee80211_link_data *link = sdata->link[link_id];
-	struct ieee80211_bss_conf *link_conf = sdata->vif.link_conf[link_id];
+	struct ieee80211_link_data *link;
+	struct ieee80211_bss_conf *link_conf;
+
+	link = sdata_dereference(sdata->link[link_id], sdata);
+	if (!link)
+		return -ENOLINK;
+
+	link_conf = link->conf;
 
 	old = sdata_dereference(link->u.ap.beacon, sdata);
 	if (old)
@@ -1264,7 +1269,7 @@ static int ieee80211_start_ap(struct wiphy *wiphy, struct net_device *dev,
 	if (ieee80211_hw_check(&local->hw, HAS_RATE_CONTROL))
 		link_conf->beacon_tx_rate = params->beacon_rate;
 
-	err = ieee80211_assign_beacon(sdata, &params->beacon, NULL, NULL);
+	err = ieee80211_assign_beacon(sdata, link, &params->beacon, NULL, NULL);
 	if (err < 0)
 		goto error;
 	changed |= err;
@@ -1300,7 +1305,7 @@ static int ieee80211_start_ap(struct wiphy *wiphy, struct net_device *dev,
 
 	ieee80211_recalc_dtim(local, sdata);
 	ieee80211_vif_cfg_change_notify(sdata, BSS_CHANGED_SSID);
-	ieee80211_link_info_change_notify(sdata, link_id, changed);
+	ieee80211_link_info_change_notify(sdata, link, changed);
 
 	netif_carrier_on(dev);
 	list_for_each_entry(vlan, &sdata->u.ap.vlans, u.vlan.list)
@@ -1320,25 +1325,30 @@ static int ieee80211_change_beacon(struct wiphy *wiphy, struct net_device *dev,
 				   struct cfg80211_beacon_data *params)
 {
 	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
+	struct ieee80211_link_data *link;
 	struct beacon_data *old;
 	int err;
-	struct ieee80211_bss_conf *link_conf =
-		sdata->vif.link_conf[params->link_id];
+	struct ieee80211_bss_conf *link_conf;
 
 	sdata_assert_lock(sdata);
 
+	link = sdata_dereference(sdata->link[params->link_id], sdata);
+	if (!link)
+		return -ENOLINK;
+
+	link_conf = link->conf;
+
 	/* don't allow changing the beacon while a countdown is in place - offset
 	 * of channel switch counter may change
 	 */
 	if (link_conf->csa_active || link_conf->color_change_active)
 		return -EBUSY;
 
-	old = sdata_dereference(sdata->link[params->link_id]->u.ap.beacon,
-				sdata);
+	old = sdata_dereference(link->u.ap.beacon, sdata);
 	if (!old)
 		return -ENOENT;
 
-	err = ieee80211_assign_beacon(sdata, params, NULL, NULL);
+	err = ieee80211_assign_beacon(sdata, link, params, NULL, NULL);
 	if (err < 0)
 		return err;
 
@@ -1348,7 +1358,7 @@ static int ieee80211_change_beacon(struct wiphy *wiphy, struct net_device *dev,
 		err |= BSS_CHANGED_HE_BSS_COLOR;
 	}
 
-	ieee80211_link_info_change_notify(sdata, params->link_id, err);
+	ieee80211_link_info_change_notify(sdata, link, err);
 	return 0;
 }
 
@@ -1373,8 +1383,9 @@ static int ieee80211_stop_ap(struct wiphy *wiphy, struct net_device *dev,
 	struct fils_discovery_data *old_fils_discovery;
 	struct unsol_bcast_probe_resp_data *old_unsol_bcast_probe_resp;
 	struct cfg80211_chan_def chandef;
-	struct ieee80211_link_data *link = sdata->link[link_id];
-	struct ieee80211_bss_conf *link_conf = sdata->vif.link_conf[link_id];
+	struct ieee80211_link_data *link =
+		sdata_dereference(sdata->link[link_id], sdata);
+	struct ieee80211_bss_conf *link_conf = link->conf;
 
 	sdata_assert_lock(sdata);
 
@@ -1431,7 +1442,7 @@ static int ieee80211_stop_ap(struct wiphy *wiphy, struct net_device *dev,
 	sdata->beacon_rate_set = false;
 	sdata->vif.cfg.ssid_len = 0;
 	clear_bit(SDATA_STATE_OFFCHANNEL_BEACON_STOPPED, &sdata->state);
-	ieee80211_link_info_change_notify(sdata, link_id,
+	ieee80211_link_info_change_notify(sdata, link,
 					  BSS_CHANGED_BEACON_ENABLED);
 
 	if (sdata->wdev.cac_started) {
@@ -1589,14 +1600,16 @@ static int sta_link_apply_parameters(struct ieee80211_local *local,
 	struct ieee80211_supported_band *sband;
 	struct ieee80211_sub_if_data *sdata = sta->sdata;
 	u32 link_id = params->link_id < 0 ? 0 : params->link_id;
+	struct ieee80211_link_data *link =
+		sdata_dereference(sdata->link[link_id], sdata);
 	struct link_sta_info *link_sta =
 		rcu_dereference_protected(sta->link[link_id],
 					  lockdep_is_held(&local->sta_mtx));
 
-	if (!link_sta)
+	if (!link || !link_sta)
 		return -EINVAL;
 
-	sband = ieee80211_get_link_sband(sdata, link_id);
+	sband = ieee80211_get_link_sband(link);
 	if (!sband)
 		return -EINVAL;
 
@@ -1616,7 +1629,7 @@ static int sta_link_apply_parameters(struct ieee80211_local *local,
 
 	if (params->supported_rates &&
 	    params->supported_rates_len) {
-		ieee80211_parse_bitrates(&sdata->vif.link_conf[link_id]->chandef,
+		ieee80211_parse_bitrates(&link->conf->chandef,
 					 sband, params->supported_rates,
 					 params->supported_rates_len,
 					 &link_sta->pub->supp_rates[sband->band]);
@@ -1667,9 +1680,14 @@ static int sta_apply_parameters(struct ieee80211_local *local,
 	struct ieee80211_sub_if_data *sdata = sta->sdata;
 	u32 link_id = params->link_sta_params.link_id < 0 ?
 		      0 : params->link_sta_params.link_id;
+	struct ieee80211_link_data *link;
 	u32 mask, set;
 
-	sband = ieee80211_get_link_sband(sdata, link_id);
+	link = sdata_dereference(sdata->link[link_id], sdata);
+	if (!link)
+		return -ENOLINK;
+
+	sband = ieee80211_get_link_sband(link);
 	if (!sband)
 		return -EINVAL;
 
@@ -1987,7 +2005,14 @@ static int ieee80211_change_station(struct wiphy *wiphy,
 		}
 	}
 
-	err = sta_apply_parameters(local, sta, params);
+	/* we use sta_info_get_bss() so this might be different */
+	if (sdata != sta->sdata) {
+		mutex_lock_nested(&sta->sdata->wdev.mtx, 1);
+		err = sta_apply_parameters(local, sta, params);
+		mutex_unlock(&sta->sdata->wdev.mtx);
+	} else {
+		err = sta_apply_parameters(local, sta, params);
+	}
 	if (err)
 		goto out_err;
 
@@ -2374,7 +2399,8 @@ static int ieee80211_update_mesh_config(struct wiphy *wiphy,
 	if (_chg_mesh_attr(NL80211_MESHCONF_HT_OPMODE, mask)) {
 		conf->ht_opmode = nconf->ht_opmode;
 		sdata->vif.bss_conf.ht_operation_mode = nconf->ht_opmode;
-		ieee80211_link_info_change_notify(sdata, 0, BSS_CHANGED_HT);
+		ieee80211_link_info_change_notify(sdata, &sdata->deflink,
+						  BSS_CHANGED_HT);
 	}
 	if (_chg_mesh_attr(NL80211_MESHCONF_HWMP_PATH_TO_ROOT_TIMEOUT, mask))
 		conf->dot11MeshHWMPactivePathToRootTimeout =
@@ -2426,7 +2452,7 @@ static int ieee80211_join_mesh(struct wiphy *wiphy, struct net_device *dev,
 	sdata->deflink.needed_rx_chains = sdata->local->rx_chains;
 
 	mutex_lock(&sdata->local->mtx);
-	err = ieee80211_link_use_channel(sdata->link[0], &setup->chandef,
+	err = ieee80211_link_use_channel(&sdata->deflink, &setup->chandef,
 					 IEEE80211_CHANCTX_SHARED);
 	mutex_unlock(&sdata->local->mtx);
 	if (err)
@@ -2441,7 +2467,7 @@ static int ieee80211_leave_mesh(struct wiphy *wiphy, struct net_device *dev)
 
 	ieee80211_stop_mesh(sdata);
 	mutex_lock(&sdata->local->mtx);
-	ieee80211_link_release_channel(sdata->link[0]);
+	ieee80211_link_release_channel(&sdata->deflink);
 	kfree(sdata->u.mesh.ie);
 	mutex_unlock(&sdata->local->mtx);
 
@@ -2529,7 +2555,7 @@ static int ieee80211_change_bss(struct wiphy *wiphy,
 		changed |= BSS_CHANGED_P2P_PS;
 	}
 
-	ieee80211_link_info_change_notify(sdata, 0, changed);
+	ieee80211_link_info_change_notify(sdata, &sdata->deflink, changed);
 
 	return 0;
 }
@@ -2570,7 +2596,8 @@ static int ieee80211_set_txq_params(struct wiphy *wiphy,
 		return -EINVAL;
 	}
 
-	ieee80211_link_info_change_notify(sdata, 0, BSS_CHANGED_QOS);
+	ieee80211_link_info_change_notify(sdata, &sdata->deflink,
+					  BSS_CHANGED_QOS);
 
 	return 0;
 }
@@ -2719,7 +2746,8 @@ static int ieee80211_set_mcast_rate(struct wiphy *wiphy, struct net_device *dev,
 	memcpy(sdata->vif.bss_conf.mcast_rate, rate,
 	       sizeof(int) * NUM_NL80211_BANDS);
 
-	ieee80211_link_info_change_notify(sdata, 0, BSS_CHANGED_MCAST_RATE);
+	ieee80211_link_info_change_notify(sdata, &sdata->deflink,
+					  BSS_CHANGED_MCAST_RATE);
 
 	return 0;
 }
@@ -2934,7 +2962,7 @@ static int ieee80211_testmode_dump(struct wiphy *wiphy,
 #endif
 
 int __ieee80211_request_smps_mgd(struct ieee80211_sub_if_data *sdata,
-				 unsigned int link_id,
+				 struct ieee80211_link_data *link,
 				 enum ieee80211_smps_mode smps_mode)
 {
 	const u8 *ap;
@@ -2948,8 +2976,8 @@ int __ieee80211_request_smps_mgd(struct ieee80211_sub_if_data *sdata,
 	if (WARN_ON_ONCE(sdata->vif.type != NL80211_IFTYPE_STATION))
 		return -EINVAL;
 
-	old_req = sdata->link[link_id]->u.mgd.req_smps;
-	sdata->link[link_id]->u.mgd.req_smps = smps_mode;
+	old_req = link->u.mgd.req_smps;
+	link->u.mgd.req_smps = smps_mode;
 
 	if (old_req == smps_mode &&
 	    smps_mode != IEEE80211_SMPS_AUTOMATIC)
@@ -2961,10 +2989,10 @@ int __ieee80211_request_smps_mgd(struct ieee80211_sub_if_data *sdata,
 	 * the new value until we associate.
 	 */
 	if (!sdata->u.mgd.associated ||
-	    sdata->vif.link_conf[link_id]->chandef.width == NL80211_CHAN_WIDTH_20_NOHT)
+	    link->conf->chandef.width == NL80211_CHAN_WIDTH_20_NOHT)
 		return 0;
 
-	ap = sdata->link[link_id]->u.mgd.bssid;
+	ap = link->u.mgd.bssid;
 
 	rcu_read_lock();
 	list_for_each_entry_rcu(sta, &sdata->local->sta_list, list) {
@@ -2988,7 +3016,7 @@ int __ieee80211_request_smps_mgd(struct ieee80211_sub_if_data *sdata,
 	err = ieee80211_send_smps_action(sdata, smps_mode,
 					 ap, ap);
 	if (err)
-		sdata->link[link_id]->u.mgd.req_smps = old_req;
+		link->u.mgd.req_smps = old_req;
 	else if (smps_mode != IEEE80211_SMPS_OFF && tdls_peer_found)
 		ieee80211_teardown_tdls_peers(sdata);
 
@@ -3018,10 +3046,14 @@ static int ieee80211_set_power_mgmt(struct wiphy *wiphy, struct net_device *dev,
 	/* no change, but if automatic follow powersave */
 	sdata_lock(sdata);
 	for (link_id = 0; link_id < ARRAY_SIZE(sdata->link); link_id++) {
-		if (!sdata->link[link_id])
+		struct ieee80211_link_data *link;
+
+		link = sdata_dereference(sdata->link[link_id], sdata);
+
+		if (!link)
 			continue;
-		__ieee80211_request_smps_mgd(sdata, link_id,
-					     sdata->link[link_id]->u.mgd.req_smps);
+		__ieee80211_request_smps_mgd(sdata, link,
+					     link->u.mgd.req_smps);
 	}
 	sdata_unlock(sdata);
 
@@ -3060,7 +3092,8 @@ static int ieee80211_set_cqm_rssi_config(struct wiphy *wiphy,
 	/* tell the driver upon association, unless already associated */
 	if (sdata->u.mgd.associated &&
 	    sdata->vif.driver_flags & IEEE80211_VIF_SUPPORTS_CQM_RSSI)
-		ieee80211_link_info_change_notify(sdata, 0, BSS_CHANGED_CQM);
+		ieee80211_link_info_change_notify(sdata, &sdata->deflink,
+						  BSS_CHANGED_CQM);
 
 	return 0;
 }
@@ -3085,7 +3118,8 @@ static int ieee80211_set_cqm_rssi_range_config(struct wiphy *wiphy,
 	/* tell the driver upon association, unless already associated */
 	if (sdata->u.mgd.associated &&
 	    sdata->vif.driver_flags & IEEE80211_VIF_SUPPORTS_CQM_RSSI)
-		ieee80211_link_info_change_notify(sdata, 0, BSS_CHANGED_CQM);
+		ieee80211_link_info_change_notify(sdata, &sdata->deflink,
+						  BSS_CHANGED_CQM);
 
 	return 0;
 }
@@ -3177,7 +3211,7 @@ static int ieee80211_start_radar_detection(struct wiphy *wiphy,
 	sdata->deflink.smps_mode = IEEE80211_SMPS_OFF;
 	sdata->deflink.needed_rx_chains = local->rx_chains;
 
-	err = ieee80211_link_use_channel(sdata->link[0], chandef,
+	err = ieee80211_link_use_channel(&sdata->deflink, chandef,
 					 IEEE80211_CHANCTX_SHARED);
 	if (err)
 		goto out_unlock;
@@ -3206,7 +3240,7 @@ static void ieee80211_end_cac(struct wiphy *wiphy,
 		cancel_delayed_work(&sdata->deflink.dfs_cac_timer_work);
 
 		if (sdata->wdev.cac_started) {
-			ieee80211_link_release_channel(sdata->link[0]);
+			ieee80211_link_release_channel(&sdata->deflink);
 			sdata->wdev.cac_started = false;
 		}
 	}
@@ -3353,7 +3387,7 @@ static int ieee80211_set_after_csa_beacon(struct ieee80211_sub_if_data *sdata,
 		if (!sdata->deflink.u.ap.next_beacon)
 			return -EINVAL;
 
-		err = ieee80211_assign_beacon(sdata,
+		err = ieee80211_assign_beacon(sdata, &sdata->deflink,
 					      sdata->deflink.u.ap.next_beacon,
 					      NULL, NULL);
 		ieee80211_free_next_beacon(&sdata->deflink);
@@ -3410,7 +3444,7 @@ static int __ieee80211_csa_finalize(struct ieee80211_sub_if_data *sdata)
 		if (sdata->deflink.reserved_ready)
 			return 0;
 
-		return ieee80211_link_use_reserved_context(sdata->link[0]);
+		return ieee80211_link_use_reserved_context(&sdata->deflink);
 	}
 
 	if (!cfg80211_chandef_identical(&sdata->vif.bss_conf.chandef,
@@ -3423,7 +3457,7 @@ static int __ieee80211_csa_finalize(struct ieee80211_sub_if_data *sdata)
 	if (err)
 		return err;
 
-	ieee80211_link_info_change_notify(sdata, 0, changed);
+	ieee80211_link_info_change_notify(sdata, &sdata->deflink, changed);
 
 	if (sdata->deflink.csa_block_tx) {
 		ieee80211_wake_vif_queues(local, sdata,
@@ -3522,7 +3556,9 @@ static int ieee80211_set_csa_beacon(struct ieee80211_sub_if_data *sdata,
 		csa.n_counter_offsets_presp = params->n_counter_offsets_presp;
 		csa.count = params->count;
 
-		err = ieee80211_assign_beacon(sdata, &params->beacon_csa, &csa, NULL);
+		err = ieee80211_assign_beacon(sdata, &sdata->deflink,
+					      &params->beacon_csa, &csa,
+					      NULL);
 		if (err < 0) {
 			ieee80211_free_next_beacon(&sdata->deflink);
 			return err;
@@ -3675,7 +3711,7 @@ __ieee80211_channel_switch(struct wiphy *wiphy, struct net_device *dev,
 	if (err)
 		goto out;
 
-	err = ieee80211_link_reserve_chanctx(sdata->link[0], &params->chandef,
+	err = ieee80211_link_reserve_chanctx(&sdata->deflink, &params->chandef,
 					     chanctx->mode,
 					     params->radar_required);
 	if (err)
@@ -3684,7 +3720,7 @@ __ieee80211_channel_switch(struct wiphy *wiphy, struct net_device *dev,
 	/* if reservation is invalid then this will fail */
 	err = ieee80211_check_combinations(sdata, NULL, chanctx->mode, 0);
 	if (err) {
-		ieee80211_link_unreserve_chanctx(sdata->link[0]);
+		ieee80211_link_unreserve_chanctx(&sdata->deflink);
 		goto out;
 	}
 
@@ -3694,7 +3730,7 @@ __ieee80211_channel_switch(struct wiphy *wiphy, struct net_device *dev,
 
 	err = ieee80211_set_csa_beacon(sdata, params, &changed);
 	if (err) {
-		ieee80211_link_unreserve_chanctx(sdata->link[0]);
+		ieee80211_link_unreserve_chanctx(&sdata->deflink);
 		goto out;
 	}
 
@@ -3711,7 +3747,8 @@ __ieee80211_channel_switch(struct wiphy *wiphy, struct net_device *dev,
 					  params->count, params->block_tx);
 
 	if (changed) {
-		ieee80211_link_info_change_notify(sdata, 0, changed);
+		ieee80211_link_info_change_notify(sdata, &sdata->deflink,
+						  changed);
 		drv_channel_switch_beacon(sdata, &params->chandef);
 	} else {
 		/* if the beacon didn't change, we can finalize immediately */
@@ -3950,12 +3987,19 @@ static int ieee80211_cfg_get_channel(struct wiphy *wiphy,
 	struct ieee80211_sub_if_data *sdata = IEEE80211_WDEV_TO_SUB_IF(wdev);
 	struct ieee80211_local *local = wiphy_priv(wiphy);
 	struct ieee80211_chanctx_conf *chanctx_conf;
+	struct ieee80211_link_data *link;
 	int ret = -ENODATA;
 
 	rcu_read_lock();
-	chanctx_conf = rcu_dereference(sdata->vif.link_conf[link_id]->chanctx_conf);
+	link = rcu_dereference(sdata->link[link_id]);
+	if (!link) {
+		ret = -ENOLINK;
+		goto out;
+	}
+
+	chanctx_conf = rcu_dereference(link->conf->chanctx_conf);
 	if (chanctx_conf) {
-		*chandef = sdata->vif.link_conf[link_id]->chandef;
+		*chandef = link->conf->chandef;
 		ret = 0;
 	} else if (local->open_count > 0 &&
 		   local->open_count == local->monitors &&
@@ -3966,6 +4010,7 @@ static int ieee80211_cfg_get_channel(struct wiphy *wiphy,
 			*chandef = local->_oper_chandef;
 		ret = 0;
 	}
+out:
 	rcu_read_unlock();
 
 	return ret;
@@ -4009,13 +4054,15 @@ static int ieee80211_set_ap_chanwidth(struct wiphy *wiphy,
 				      struct cfg80211_chan_def *chandef)
 {
 	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
+	struct ieee80211_link_data *link;
 	int ret;
 	u32 changed = 0;
 
-	ret = ieee80211_link_change_bandwidth(sdata->link[link_id], chandef,
-					      &changed);
+	link = sdata_dereference(sdata->link[link_id], sdata);
+
+	ret = ieee80211_link_change_bandwidth(link, chandef, &changed);
 	if (ret == 0)
-		ieee80211_link_info_change_notify(sdata, link_id, changed);
+		ieee80211_link_info_change_notify(sdata, link, changed);
 
 	return ret;
 }
@@ -4358,7 +4405,7 @@ ieee80211_set_after_color_change_beacon(struct ieee80211_sub_if_data *sdata,
 		if (!sdata->deflink.u.ap.next_beacon)
 			return -EINVAL;
 
-		ret = ieee80211_assign_beacon(sdata,
+		ret = ieee80211_assign_beacon(sdata, &sdata->deflink,
 					      sdata->deflink.u.ap.next_beacon,
 					      NULL, NULL);
 		ieee80211_free_next_beacon(&sdata->deflink);
@@ -4401,7 +4448,8 @@ ieee80211_set_color_change_beacon(struct ieee80211_sub_if_data *sdata,
 			params->counter_offset_presp;
 		color_change.count = params->count;
 
-		err = ieee80211_assign_beacon(sdata, &params->beacon_color_change,
+		err = ieee80211_assign_beacon(sdata, &sdata->deflink,
+					      &params->beacon_color_change,
 					      NULL, &color_change);
 		if (err < 0) {
 			ieee80211_free_next_beacon(&sdata->deflink);
@@ -4424,7 +4472,7 @@ ieee80211_color_change_bss_config_notify(struct ieee80211_sub_if_data *sdata,
 	sdata->vif.bss_conf.he_bss_color.enabled = enable;
 	changed |= BSS_CHANGED_HE_BSS_COLOR;
 
-	ieee80211_link_info_change_notify(sdata, 0, changed);
+	ieee80211_link_info_change_notify(sdata, &sdata->deflink, changed);
 
 	if (!sdata->vif.bss_conf.nontransmitted && sdata->vif.mbssid_tx_vif) {
 		struct ieee80211_sub_if_data *child;
@@ -4434,7 +4482,8 @@ ieee80211_color_change_bss_config_notify(struct ieee80211_sub_if_data *sdata,
 			if (child != sdata && child->vif.mbssid_tx_vif == &sdata->vif) {
 				child->vif.bss_conf.he_bss_color.color = color;
 				child->vif.bss_conf.he_bss_color.enabled = enable;
-				ieee80211_link_info_change_notify(child, 0,
+				ieee80211_link_info_change_notify(child,
+								  &child->deflink,
 								  BSS_CHANGED_HE_BSS_COLOR);
 			}
 		}
diff --git a/net/mac80211/chan.c b/net/mac80211/chan.c
index 6853b563fb6c..8d384956fde5 100644
--- a/net/mac80211/chan.c
+++ b/net/mac80211/chan.c
@@ -67,14 +67,12 @@ static bool ieee80211_can_create_new_chanctx(struct ieee80211_local *local)
 }
 
 static struct ieee80211_chanctx *
-ieee80211_vif_get_chanctx(struct ieee80211_sub_if_data *sdata,
-			  unsigned int link_id)
+ieee80211_link_get_chanctx(struct ieee80211_link_data *link)
 {
-	struct ieee80211_bss_conf *link_conf = sdata->vif.link_conf[link_id];
-	struct ieee80211_local *local __maybe_unused = sdata->local;
+	struct ieee80211_local *local __maybe_unused = link->sdata->local;
 	struct ieee80211_chanctx_conf *conf;
 
-	conf = rcu_dereference_protected(link_conf->chanctx_conf,
+	conf = rcu_dereference_protected(link->conf->chanctx_conf,
 					 lockdep_is_held(&local->chanctx_mtx));
 	if (!conf)
 		return NULL;
@@ -82,12 +80,6 @@ ieee80211_vif_get_chanctx(struct ieee80211_sub_if_data *sdata,
 	return container_of(conf, struct ieee80211_chanctx, conf);
 }
 
-static struct ieee80211_chanctx *
-ieee80211_link_get_chanctx(struct ieee80211_link_data *link)
-{
-	return ieee80211_vif_get_chanctx(link->sdata, link->link_id);
-}
-
 static const struct cfg80211_chan_def *
 ieee80211_chanctx_reserved_chandef(struct ieee80211_local *local,
 				   struct ieee80211_chanctx *ctx,
@@ -122,8 +114,7 @@ ieee80211_chanctx_non_reserved_chandef(struct ieee80211_local *local,
 
 	list_for_each_entry(link, &ctx->assigned_links,
 			    assigned_chanctx_list) {
-		struct ieee80211_bss_conf *link_conf =
-			link->sdata->vif.link_conf[link->link_id];
+		struct ieee80211_bss_conf *link_conf = link->conf;
 
 		if (link->reserved_chanctx)
 			continue;
@@ -254,7 +245,6 @@ ieee80211_get_max_required_bw(struct ieee80211_sub_if_data *sdata,
 	enum nl80211_chan_width max_bw = NL80211_CHAN_WIDTH_20_NOHT;
 	struct sta_info *sta;
 
-	rcu_read_lock();
 	list_for_each_entry_rcu(sta, &sdata->local->sta_list, list) {
 		if (sdata != sta->sdata &&
 		    !(sta->sdata->bss && sta->sdata->bss == sdata->bss))
@@ -262,7 +252,6 @@ ieee80211_get_max_required_bw(struct ieee80211_sub_if_data *sdata,
 
 		max_bw = max(max_bw, ieee80211_get_sta_bw(sta, link_id));
 	}
-	rcu_read_unlock();
 
 	return max_bw;
 }
@@ -275,10 +264,11 @@ ieee80211_get_chanctx_vif_max_required_bw(struct ieee80211_sub_if_data *sdata,
 	struct ieee80211_vif *vif = &sdata->vif;
 	int link_id;
 
+	rcu_read_lock();
 	for (link_id = 0; link_id < ARRAY_SIZE(sdata->link); link_id++) {
 		enum nl80211_chan_width width = NL80211_CHAN_WIDTH_20_NOHT;
 		struct ieee80211_bss_conf *link_conf =
-			sdata->vif.link_conf[link_id];
+			rcu_dereference(sdata->vif.link_conf[link_id]);
 
 		if (!link_conf)
 			continue;
@@ -319,6 +309,7 @@ ieee80211_get_chanctx_vif_max_required_bw(struct ieee80211_sub_if_data *sdata,
 
 		max_bw = max(max_bw, width);
 	}
+	rcu_read_unlock();
 
 	return max_bw;
 }
@@ -345,7 +336,7 @@ ieee80211_get_chanctx_max_required_bw(struct ieee80211_local *local,
 	/* use the configured bandwidth in case of monitor interface */
 	sdata = rcu_dereference(local->monitor_sdata);
 	if (sdata &&
-	    rcu_access_pointer(sdata->vif.link_conf[0]->chanctx_conf) == conf)
+	    rcu_access_pointer(sdata->vif.bss_conf.chanctx_conf) == conf)
 		max_bw = max(max_bw, conf->def.width);
 
 	rcu_read_unlock();
@@ -419,7 +410,7 @@ static void ieee80211_chan_bw_change(struct ieee80211_local *local,
 
 		for (link_id = 0; link_id < ARRAY_SIZE(sta->sdata->link); link_id++) {
 			struct ieee80211_bss_conf *link_conf =
-				sdata->vif.link_conf[link_id];
+				rcu_dereference(sdata->vif.link_conf[link_id]);
 			struct link_sta_info *link_sta;
 
 			if (!link_conf)
@@ -572,8 +563,11 @@ bool ieee80211_is_radar_required(struct ieee80211_local *local)
 		unsigned int link_id;
 
 		for (link_id = 0; link_id < ARRAY_SIZE(sdata->link); link_id++) {
-			if (sdata->link[link_id] &&
-			    sdata->link[link_id]->radar_required) {
+			struct ieee80211_link_data *link;
+
+			link = rcu_dereference(sdata->link[link_id]);
+
+			if (link && link->radar_required) {
 				rcu_read_unlock();
 				return true;
 			}
@@ -602,15 +596,15 @@ ieee80211_chanctx_radar_required(struct ieee80211_local *local,
 		if (!ieee80211_sdata_running(sdata))
 			continue;
 		for (link_id = 0; link_id < ARRAY_SIZE(sdata->link); link_id++) {
-			struct ieee80211_bss_conf *link_conf =
-				sdata->vif.link_conf[link_id];
+			struct ieee80211_link_data *link;
 
-			if (!link_conf)
+			link = rcu_dereference(sdata->link[link_id]);
+			if (!link)
 				continue;
 
-			if (rcu_access_pointer(link_conf->chanctx_conf) != conf)
+			if (rcu_access_pointer(link->conf->chanctx_conf) != conf)
 				continue;
-			if (!sdata->link[link_id]->radar_required)
+			if (!link->radar_required)
 				continue;
 			required = true;
 			break;
@@ -774,7 +768,7 @@ void ieee80211_recalc_chanctx_chantype(struct ieee80211_local *local,
 
 		for (link_id = 0; link_id < ARRAY_SIZE(sdata->link); link_id++) {
 			struct ieee80211_bss_conf *link_conf =
-				sdata->vif.link_conf[link_id];
+				rcu_dereference(sdata->vif.link_conf[link_id]);
 
 			if (!link_conf)
 				continue;
@@ -850,7 +844,7 @@ static int ieee80211_assign_link_chanctx(struct ieee80211_link_data *link,
 	if (WARN_ON(sdata->vif.type == NL80211_IFTYPE_NAN))
 		return -ENOTSUPP;
 
-	conf = rcu_dereference_protected(sdata->vif.link_conf[link_id]->chanctx_conf,
+	conf = rcu_dereference_protected(link->conf->chanctx_conf,
 					 lockdep_is_held(&local->chanctx_mtx));
 
 	if (conf) {
@@ -872,7 +866,7 @@ static int ieee80211_assign_link_chanctx(struct ieee80211_link_data *link,
 	}
 
 out:
-	rcu_assign_pointer(sdata->vif.link_conf[link_id]->chanctx_conf, conf);
+	rcu_assign_pointer(link->conf->chanctx_conf, conf);
 
 	sdata->vif.cfg.idle = !conf;
 
@@ -931,14 +925,14 @@ void ieee80211_recalc_smps_chanctx(struct ieee80211_local *local,
 		}
 
 		for (link_id = 0; link_id < ARRAY_SIZE(sdata->link); link_id++) {
-			struct ieee80211_link_data *link = sdata->link[link_id];
-			struct ieee80211_bss_conf *link_conf =
-				sdata->vif.link_conf[link_id];
+			struct ieee80211_link_data *link;
 
-			if (!link_conf)
+			link = rcu_dereference(sdata->link[link_id]);
+
+			if (!link)
 				continue;
 
-			if (rcu_access_pointer(link_conf->chanctx_conf) != &chanctx->conf)
+			if (rcu_access_pointer(link->conf->chanctx_conf) != &chanctx->conf)
 				continue;
 
 			switch (link->smps_mode) {
@@ -968,7 +962,7 @@ void ieee80211_recalc_smps_chanctx(struct ieee80211_local *local,
 	/* Disable SMPS for the monitor interface */
 	sdata = rcu_dereference(local->monitor_sdata);
 	if (sdata &&
-	    rcu_access_pointer(sdata->vif.link_conf[0]->chanctx_conf) == &chanctx->conf)
+	    rcu_access_pointer(sdata->vif.bss_conf.chanctx_conf) == &chanctx->conf)
 		rx_chains_dynamic = rx_chains_static = local->rx_chains;
 
 	rcu_read_unlock();
@@ -998,7 +992,7 @@ __ieee80211_link_copy_chanctx_to_vlans(struct ieee80211_link_data *link,
 {
 	struct ieee80211_sub_if_data *sdata = link->sdata;
 	unsigned int link_id = link->link_id;
-	struct ieee80211_bss_conf *link_conf = sdata->vif.link_conf[link_id];
+	struct ieee80211_bss_conf *link_conf = link->conf;
 	struct ieee80211_local *local __maybe_unused = sdata->local;
 	struct ieee80211_sub_if_data *vlan;