wifi: cfg80211: do some rework towards MLO link APIs

In order to support multi-link operation with multiple links,
start adding some APIs. The notable addition here is to have
the link ID in a new nl80211 attribute, that will be used to
differentiate the links in many nl80211 operations.

So far, this patch adds the netlink NL80211_ATTR_MLO_LINK_ID
attribute (as well as the NL80211_ATTR_MLO_LINKS attribute)
and plugs it through the system in some places, checking the
validity etc. along with other infrastructure needed for it.

For now, I've decided to include only the over-the-air link
ID in the API. I know we discussed that we eventually need to
have to have other ways of identifying a link, but for local
AP mode and auth/assoc commands as well as set_key etc. we'll
use the OTA ID.

Also included in this patch is some refactoring of the data
structures in struct wireless_dev, splitting for the first
time the data into type dependent pieces, to make reasoning
about these things easier.

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

33 files changed, 1255 insertions, 533 deletions

diff --git a/drivers/net/wireless/ath/ath6kl/cfg80211.c b/drivers/net/wireless/ath/ath6kl/cfg80211.c
index bd1183830e91..33ed54738d47 100644
--- a/drivers/net/wireless/ath/ath6kl/cfg80211.c
+++ b/drivers/net/wireless/ath/ath6kl/cfg80211.c
@@ -1119,7 +1119,7 @@ void ath6kl_cfg80211_ch_switch_notify(struct ath6kl_vif *vif, int freq,
 					NL80211_CHAN_HT20 : NL80211_CHAN_NO_HT);
 
 	mutex_lock(&vif->wdev.mtx);
-	cfg80211_ch_switch_notify(vif->ndev, &chandef);
+	cfg80211_ch_switch_notify(vif->ndev, &chandef, 0);
 	mutex_unlock(&vif->wdev.mtx);
 }
 
@@ -2967,7 +2967,8 @@ static int ath6kl_change_beacon(struct wiphy *wiphy, struct net_device *dev,
 	return ath6kl_set_ies(vif, beacon);
 }
 
-static int ath6kl_stop_ap(struct wiphy *wiphy, struct net_device *dev)
+static int ath6kl_stop_ap(struct wiphy *wiphy, struct net_device *dev,
+			  unsigned int link_id)
 {
 	struct ath6kl *ar = ath6kl_priv(dev);
 	struct ath6kl_vif *vif = netdev_priv(dev);
@@ -3368,6 +3369,7 @@ static int ath6kl_cfg80211_sscan_stop(struct wiphy *wiphy,
 
 static int ath6kl_cfg80211_set_bitrate(struct wiphy *wiphy,
 				       struct net_device *dev,
+				       unsigned int link_id,
 				       const u8 *addr,
 				       const struct cfg80211_bitrate_mask *mask)
 {
diff --git a/drivers/net/wireless/ath/wil6210/cfg80211.c b/drivers/net/wireless/ath/wil6210/cfg80211.c
index 8f2638f5b87b..f93bdffa4d1d 100644
--- a/drivers/net/wireless/ath/wil6210/cfg80211.c
+++ b/drivers/net/wireless/ath/wil6210/cfg80211.c
@@ -2098,8 +2098,8 @@ static int wil_cfg80211_change_beacon(struct wiphy *wiphy,
 			     bcon->tail_len))
 		privacy = 1;
 
-	memcpy(vif->ssid, wdev->ssid, wdev->ssid_len);
-	vif->ssid_len = wdev->ssid_len;
+	memcpy(vif->ssid, wdev->u.ap.ssid, wdev->u.ap.ssid_len);
+	vif->ssid_len = wdev->u.ap.ssid_len;
 
 	/* in case privacy has changed, need to restart the AP */
 	if (vif->privacy != privacy) {
@@ -2108,7 +2108,7 @@ static int wil_cfg80211_change_beacon(struct wiphy *wiphy,
 
 		rc = _wil_cfg80211_start_ap(wiphy, ndev, vif->ssid,
 					    vif->ssid_len, privacy,
-					    wdev->beacon_interval,
+					    wdev->links[0].ap.beacon_interval,
 					    vif->channel,
 					    vif->wmi_edmg_channel, bcon,
 					    vif->hidden_ssid,
@@ -2186,7 +2186,8 @@ static int wil_cfg80211_start_ap(struct wiphy *wiphy,
 }
 
 static int wil_cfg80211_stop_ap(struct wiphy *wiphy,
-				struct net_device *ndev)
+				struct net_device *ndev,
+				unsigned int link_id)
 {
 	struct wil6210_priv *wil = wiphy_to_wil(wiphy);
 	struct wil6210_vif *vif = ndev_to_vif(ndev);
diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
index 605206abe424..11e1f07f83e0 100644
--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
@@ -4965,7 +4965,8 @@ exit:
 	return err;
 }
 
-static int brcmf_cfg80211_stop_ap(struct wiphy *wiphy, struct net_device *ndev)
+static int brcmf_cfg80211_stop_ap(struct wiphy *wiphy, struct net_device *ndev,
+				  unsigned int link_id)
 {
 	struct brcmf_cfg80211_info *cfg = wiphy_to_cfg(wiphy);
 	struct brcmf_if *ifp = netdev_priv(ndev);
@@ -5302,6 +5303,7 @@ exit:
 
 static int brcmf_cfg80211_get_channel(struct wiphy *wiphy,
 				      struct wireless_dev *wdev,
+				      unsigned int link_id,
 				      struct cfg80211_chan_def *chandef)
 {
 	struct brcmf_cfg80211_info *cfg = wiphy_to_cfg(wiphy);
diff --git a/drivers/net/wireless/marvell/libertas/mesh.c b/drivers/net/wireless/marvell/libertas/mesh.c
index a58c1e141f2c..90ffe8d1e0e8 100644
--- a/drivers/net/wireless/marvell/libertas/mesh.c
+++ b/drivers/net/wireless/marvell/libertas/mesh.c
@@ -109,9 +109,9 @@ static int lbs_mesh_config(struct lbs_private *priv, uint16_t action,
 
 		if (priv->mesh_dev) {
 			mesh_wdev = priv->mesh_dev->ieee80211_ptr;
-			ie->val.mesh_id_len = mesh_wdev->mesh_id_up_len;
-			memcpy(ie->val.mesh_id, mesh_wdev->ssid,
-						mesh_wdev->mesh_id_up_len);
+			ie->val.mesh_id_len = mesh_wdev->u.mesh.id_up_len;
+			memcpy(ie->val.mesh_id, mesh_wdev->u.mesh.id,
+						mesh_wdev->u.mesh.id_up_len);
 		}
 
 		ie->len = sizeof(struct mrvl_meshie_val) -
@@ -986,8 +986,8 @@ static int lbs_add_mesh(struct lbs_private *priv)
 	mesh_wdev->wiphy = priv->wdev->wiphy;
 
 	if (priv->mesh_tlv) {
-		sprintf(mesh_wdev->ssid, "mesh");
-		mesh_wdev->mesh_id_up_len = 4;
+		sprintf(mesh_wdev->u.mesh.id, "mesh");
+		mesh_wdev->u.mesh.id_up_len = 4;
 	}
 
 	mesh_wdev->netdev = mesh_dev;
diff --git a/drivers/net/wireless/marvell/mwifiex/11h.c b/drivers/net/wireless/marvell/mwifiex/11h.c
index 3fa25cd64cda..4ca8d0135708 100644
--- a/drivers/net/wireless/marvell/mwifiex/11h.c
+++ b/drivers/net/wireless/marvell/mwifiex/11h.c
@@ -304,6 +304,6 @@ void mwifiex_dfs_chan_sw_work_queue(struct work_struct *work)
 	mwifiex_dbg(priv->adapter, MSG,
 		    "indicating channel switch completion to kernel\n");
 	mutex_lock(&priv->wdev.mtx);
-	cfg80211_ch_switch_notify(priv->netdev, &priv->dfs_chandef);
+	cfg80211_ch_switch_notify(priv->netdev, &priv->dfs_chandef, 0);
 	mutex_unlock(&priv->wdev.mtx);
 }
diff --git a/drivers/net/wireless/marvell/mwifiex/cfg80211.c b/drivers/net/wireless/marvell/mwifiex/cfg80211.c
index 6f23ec34e2e2..d68c40e0e122 100644
--- a/drivers/net/wireless/marvell/mwifiex/cfg80211.c
+++ b/drivers/net/wireless/marvell/mwifiex/cfg80211.c
@@ -1753,10 +1753,12 @@ mwifiex_mgmt_stypes[NUM_NL80211_IFTYPES] = {
  * Function configures data rates to firmware using bitrate mask
  * provided by cfg80211.
  */
-static int mwifiex_cfg80211_set_bitrate_mask(struct wiphy *wiphy,
-				struct net_device *dev,
-				const u8 *peer,
-				const struct cfg80211_bitrate_mask *mask)
+static int
+mwifiex_cfg80211_set_bitrate_mask(struct wiphy *wiphy,
+				  struct net_device *dev,
+				  unsigned int link_id,
+				  const u8 *peer,
+				  const struct cfg80211_bitrate_mask *mask)
 {
 	struct mwifiex_private *priv = mwifiex_netdev_get_priv(dev);
 	u16 bitmap_rates[MAX_BITMAP_RATES_SIZE];
@@ -1998,7 +2000,8 @@ mwifiex_cfg80211_get_antenna(struct wiphy *wiphy, u32 *tx_ant, u32 *rx_ant)
 /* cfg80211 operation handler for stop ap.
  * Function stops BSS running at uAP interface.
  */
-static int mwifiex_cfg80211_stop_ap(struct wiphy *wiphy, struct net_device *dev)
+static int mwifiex_cfg80211_stop_ap(struct wiphy *wiphy, struct net_device *dev,
+				    unsigned int link_id)
 {
 	struct mwifiex_private *priv = mwifiex_netdev_get_priv(dev);
 
@@ -2421,7 +2424,7 @@ mwifiex_cfg80211_connect(struct wiphy *wiphy, struct net_device *dev,
 		return -EINVAL;
 	}
 
-	if (priv->wdev.current_bss) {
+	if (priv->wdev.connected) {
 		mwifiex_dbg(adapter, ERROR,
 			    "%s: already connected\n", dev->name);
 		return -EALREADY;
@@ -2649,7 +2652,7 @@ mwifiex_cfg80211_scan(struct wiphy *wiphy,
 		return -EBUSY;
 	}
 
-	if (!priv->wdev.current_bss && priv->scan_block)
+	if (!priv->wdev.connected && priv->scan_block)
 		priv->scan_block = false;
 
 	if (!mwifiex_stop_bg_scan(priv))
@@ -4025,6 +4028,7 @@ mwifiex_cfg80211_channel_switch(struct wiphy *wiphy, struct net_device *dev,
 
 static int mwifiex_cfg80211_get_channel(struct wiphy *wiphy,
 					struct wireless_dev *wdev,
+					unsigned int link_id,
 					struct cfg80211_chan_def *chandef)
 {
 	struct mwifiex_private *priv = mwifiex_netdev_get_priv(wdev->netdev);
diff --git a/drivers/net/wireless/microchip/wilc1000/cfg80211.c b/drivers/net/wireless/microchip/wilc1000/cfg80211.c
index 1ac4684fab25..5c2c7f1dbffd 100644
--- a/drivers/net/wireless/microchip/wilc1000/cfg80211.c
+++ b/drivers/net/wireless/microchip/wilc1000/cfg80211.c
@@ -1426,7 +1426,8 @@ static int change_beacon(struct wiphy *wiphy, struct net_device *dev,
 	return wilc_add_beacon(vif, 0, 0, beacon);
 }
 
-static int stop_ap(struct wiphy *wiphy, struct net_device *dev)
+static int stop_ap(struct wiphy *wiphy, struct net_device *dev,
+		   unsigned int link_id)
 {
 	int ret;
 	struct wilc_vif *vif = netdev_priv(dev);
diff --git a/drivers/net/wireless/quantenna/qtnfmac/cfg80211.c b/drivers/net/wireless/quantenna/qtnfmac/cfg80211.c
index 84b15a655eab..1593e810b3ca 100644
--- a/drivers/net/wireless/quantenna/qtnfmac/cfg80211.c
+++ b/drivers/net/wireless/quantenna/qtnfmac/cfg80211.c
@@ -352,7 +352,8 @@ static int qtnf_start_ap(struct wiphy *wiphy, struct net_device *dev,
 	return ret;
 }
 
-static int qtnf_stop_ap(struct wiphy *wiphy, struct net_device *dev)
+static int qtnf_stop_ap(struct wiphy *wiphy, struct net_device *dev,
+			unsigned int link_id)
 {
 	struct qtnf_vif *vif = qtnf_netdev_get_priv(dev);
 	int ret;
@@ -500,7 +501,7 @@ qtnf_dump_station(struct wiphy *wiphy, struct net_device *dev,
 
 	switch (vif->wdev.iftype) {
 	case NL80211_IFTYPE_STATION:
-		if (idx != 0 || !vif->wdev.current_bss)
+		if (idx != 0 || !vif->wdev.connected)
 			return -ENOENT;
 
 		ether_addr_copy(mac, vif->bssid);
@@ -729,7 +730,7 @@ qtnf_disconnect(struct wiphy *wiphy, struct net_device *dev,
 		pr_err("VIF%u.%u: failed to disconnect\n",
 		       mac->macid, vif->vifid);
 
-	if (vif->wdev.current_bss) {
+	if (vif->wdev.connected) {
 		netif_carrier_off(vif->netdev);
 		cfg80211_disconnected(vif->netdev, reason_code,
 				      NULL, 0, true, GFP_KERNEL);
@@ -745,10 +746,11 @@ qtnf_dump_survey(struct wiphy *wiphy, struct net_device *dev,
 	struct qtnf_wmac *mac = wiphy_priv(wiphy);
 	struct wireless_dev *wdev = dev->ieee80211_ptr;
 	struct ieee80211_supported_band *sband;
-	const struct cfg80211_chan_def *chandef = &wdev->chandef;
+	const struct cfg80211_chan_def *chandef = wdev_chandef(wdev, 0);
 	struct ieee80211_channel *chan;
 	int ret;
 
+
 	sband = wiphy->bands[NL80211_BAND_2GHZ];
 	if (sband && idx >= sband->n_channels) {
 		idx -= sband->n_channels;
@@ -765,7 +767,7 @@ qtnf_dump_survey(struct wiphy *wiphy, struct net_device *dev,
 	survey->channel = chan;
 	survey->filled = 0x0;
 
-	if (chan == chandef->chan)
+	if (chandef && chan == chandef->chan)
 		survey->filled = SURVEY_INFO_IN_USE;
 
 	ret = qtnf_cmd_get_chan_stats(mac, chan->center_freq, survey);
@@ -778,7 +780,7 @@ qtnf_dump_survey(struct wiphy *wiphy, struct net_device *dev,
 
 static int
 qtnf_get_channel(struct wiphy *wiphy, struct wireless_dev *wdev,
-		 struct cfg80211_chan_def *chandef)
+		 unsigned int link_id, struct cfg80211_chan_def *chandef)
 {
 	struct net_device *ndev = wdev->netdev;
 	struct qtnf_vif *vif;
diff --git a/drivers/net/wireless/quantenna/qtnfmac/commands.c b/drivers/net/wireless/quantenna/qtnfmac/commands.c
index c68563c83098..3d734a7a5ba8 100644
--- a/drivers/net/wireless/quantenna/qtnfmac/commands.c
+++ b/drivers/net/wireless/quantenna/qtnfmac/commands.c
@@ -2005,7 +2005,7 @@ int qtnf_cmd_send_scan(struct qtnf_wmac *mac)
 		dwell_active = scan_req->duration;
 		dwell_passive = scan_req->duration;
 	} else if (wdev->iftype == NL80211_IFTYPE_STATION &&
-		   wdev->current_bss) {
+		   wdev->connected) {
 		/* let device select dwell based on traffic conditions */
 		dwell_active = QTNF_SCAN_TIME_AUTO;
 		dwell_passive = QTNF_SCAN_TIME_AUTO;
diff --git a/drivers/net/wireless/quantenna/qtnfmac/event.c b/drivers/net/wireless/quantenna/qtnfmac/event.c
index 8dc80574d08d..4fafe370101a 100644
--- a/drivers/net/wireless/quantenna/qtnfmac/event.c
+++ b/drivers/net/wireless/quantenna/qtnfmac/event.c
@@ -189,7 +189,7 @@ qtnf_event_handle_bss_join(struct qtnf_vif *vif,
 			vif->mac->macid, vif->vifid,
 			join_info->bssid, chandef.chan->hw_value);
 
-		if (!vif->wdev.ssid_len) {
+		if (!vif->wdev.u.client.ssid_len) {
 			pr_warn("VIF%u.%u: SSID unknown for BSS:%pM\n",
 				vif->mac->macid, vif->vifid,
 				join_info->bssid);
@@ -197,7 +197,7 @@ qtnf_event_handle_bss_join(struct qtnf_vif *vif,
 			goto done;
 		}
 
-		ie = kzalloc(2 + vif->wdev.ssid_len, GFP_KERNEL);
+		ie = kzalloc(2 + vif->wdev.u.client.ssid_len, GFP_KERNEL);
 		if (!ie) {
 			pr_warn("VIF%u.%u: IE alloc failed for BSS:%pM\n",
 				vif->mac->macid, vif->vifid,
@@ -207,14 +207,15 @@ qtnf_event_handle_bss_join(struct qtnf_vif *vif,
 		}
 
 		ie[0] = WLAN_EID_SSID;
-		ie[1] = vif->wdev.ssid_len;
-		memcpy(ie + 2, vif->wdev.ssid, vif->wdev.ssid_len);
+		ie[1] = vif->wdev.u.client.ssid_len;
+		memcpy(ie + 2, vif->wdev.u.client.ssid,
+		       vif->wdev.u.client.ssid_len);
 
 		bss = cfg80211_inform_bss(wiphy, chandef.chan,
 					  CFG80211_BSS_FTYPE_UNKNOWN,
 					  join_info->bssid, 0,
 					  WLAN_CAPABILITY_ESS, 100,
-					  ie, 2 + vif->wdev.ssid_len,
+					  ie, 2 + vif->wdev.u.client.ssid_len,
 					  0, GFP_KERNEL);
 		if (!bss) {
 			pr_warn("VIF%u.%u: can't connect to unknown BSS: %pM\n",
@@ -470,14 +471,14 @@ qtnf_event_handle_freq_change(struct qtnf_wmac *mac,
 			continue;
 
 		if (vif->wdev.iftype == NL80211_IFTYPE_STATION &&
-		    !vif->wdev.current_bss)
+		    !vif->wdev.connected)
 			continue;
 
 		if (!vif->netdev)
 			continue;
 
 		mutex_lock(&vif->wdev.mtx);
-		cfg80211_ch_switch_notify(vif->netdev, &chandef);
+		cfg80211_ch_switch_notify(vif->netdev, &chandef, 0);
 		mutex_unlock(&vif->wdev.mtx);
 	}
 
diff --git a/drivers/staging/rtl8723bs/os_dep/ioctl_cfg80211.c b/drivers/staging/rtl8723bs/os_dep/ioctl_cfg80211.c
index 43b5604c0bca..349aa3c4b668 100644
--- a/drivers/staging/rtl8723bs/os_dep/ioctl_cfg80211.c
+++ b/drivers/staging/rtl8723bs/os_dep/ioctl_cfg80211.c
@@ -2086,6 +2086,7 @@ static u8 rtw_get_chan_type(struct adapter *adapter)
 }
 
 static int cfg80211_rtw_get_channel(struct wiphy *wiphy, struct wireless_dev *wdev,
+				    unsigned int link_id,
 				    struct cfg80211_chan_def *chandef)
 {
 	struct adapter *adapter = wiphy_to_adapter(wiphy);
@@ -2446,7 +2447,8 @@ static int cfg80211_rtw_change_beacon(struct wiphy *wiphy, struct net_device *nd
 	return rtw_add_beacon(adapter, info->head, info->head_len, info->tail, info->tail_len);
 }
 
-static int cfg80211_rtw_stop_ap(struct wiphy *wiphy, struct net_device *ndev)
+static int cfg80211_rtw_stop_ap(struct wiphy *wiphy, struct net_device *ndev,
+				unsigned int link_id)
 {
 	return 0;
 }
diff --git a/include/linux/ieee80211.h b/include/linux/ieee80211.h
index 5c65ae6b8154..e15771965916 100644
--- a/include/linux/ieee80211.h
+++ b/include/linux/ieee80211.h
@@ -4376,4 +4376,7 @@ enum ieee80211_range_params_max_total_ltf {
 	IEEE80211_RANGE_PARAMS_MAX_TOTAL_LTF_UNSPECIFIED,
 };
 
+/* multi-link device */
+#define IEEE80211_MLD_MAX_NUM_LINKS	15
+
 #endif /* LINUX_IEEE80211_H */
diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 6d02e12e4702..772e099fc932 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -1158,6 +1158,7 @@ struct cfg80211_mbssid_elems {
 
 /**
  * struct cfg80211_beacon_data - beacon data
+ * @link_id: the link ID for the AP MLD link sending this beacon
  * @head: head portion of beacon (before TIM IE)
  *	or %NULL if not changed
  * @tail: tail portion of beacon (after TIM IE)
@@ -1188,6 +1189,8 @@ struct cfg80211_mbssid_elems {
  *	attribute is present in beacon data or not.
  */
 struct cfg80211_beacon_data {
+	unsigned int link_id;
+
 	const u8 *head, *tail;
 	const u8 *beacon_ies;
 	const u8 *proberesp_ies;
@@ -4201,7 +4204,8 @@ struct cfg80211_ops {
 			    struct cfg80211_ap_settings *settings);
 	int	(*change_beacon)(struct wiphy *wiphy, struct net_device *dev,
 				 struct cfg80211_beacon_data *info);
-	int	(*stop_ap)(struct wiphy *wiphy, struct net_device *dev);
+	int	(*stop_ap)(struct wiphy *wiphy, struct net_device *dev,
+			   unsigned int link_id);
 
 
 	int	(*add_station)(struct wiphy *wiphy, struct net_device *dev,
@@ -4309,6 +4313,7 @@ struct cfg80211_ops {
 
 	int	(*set_bitrate_mask)(struct wiphy *wiphy,
 				    struct net_device *dev,
+				    unsigned int link_id,
 				    const u8 *peer,
 				    const struct cfg80211_bitrate_mask *mask);
 
@@ -4384,6 +4389,7 @@ struct cfg80211_ops {
 
 	int	(*get_channel)(struct wiphy *wiphy,
 			       struct wireless_dev *wdev,
+			       unsigned int link_id,
 			       struct cfg80211_chan_def *chandef);
 
 	int	(*start_p2p_device)(struct wiphy *wiphy,
@@ -4420,6 +4426,7 @@ struct cfg80211_ops {
 			       struct cfg80211_qos_map *qos_map);
 
 	int	(*set_ap_chanwidth)(struct wiphy *wiphy, struct net_device *dev,
+				    unsigned int link_id,
 				    struct cfg80211_chan_def *chandef);
 
 	int	(*add_tx_ts)(struct wiphy *wiphy, struct net_device *dev,
@@ -4545,10 +4552,14 @@ struct cfg80211_ops {
  * @WIPHY_FLAG_HAS_STATIC_WEP: The device supports static WEP key installation
  *	before connection.
  * @WIPHY_FLAG_SUPPORTS_EXT_KEK_KCK: The device supports bigger kek and kck keys
+ * @WIPHY_FLAG_SUPPORTS_MLO: This is a temporary flag gating the MLO APIs,
+ *	in order to not have them reachable in normal drivers, until we have
+ *	complete feature/interface combinations/etc. advertisement. No driver
+ *	should set this flag for now.
  */
 enum wiphy_flags {
 	WIPHY_FLAG_SUPPORTS_EXT_KEK_KCK		= BIT(0),
-	/* use hole at 1 */
+	WIPHY_FLAG_SUPPORTS_MLO			= BIT(1),
 	WIPHY_FLAG_SPLIT_SCAN_6GHZ		= BIT(2),
 	WIPHY_FLAG_NETNS_OK			= BIT(3),
 	WIPHY_FLAG_PS_ON_BY_DEFAULT		= BIT(4),
@@ -5505,6 +5516,8 @@ static inline void wiphy_unlock(struct wiphy *wiphy)
  * @netdev: (private) Used to reference back to the netdev, may be %NULL
  * @identifier: (private) Identifier used in nl80211 to identify this
  *	wireless device if it has no netdev
+ * @connected_addr: (private) BSSID or AP MLD address if connected
+ * @connected: indicates if connected or not (STA mode)
  * @current_bss: (private) Used by the internal configuration code
  * @chandef: (private) Used by the internal configuration code to track
  *	the user-set channel definition.
@@ -5585,8 +5598,6 @@ struct wireless_dev {
 	u8 address[ETH_ALEN] __aligned(sizeof(u16));
 
 	/* currently used for IBSS and SME - might be rearranged later */
-	u8 ssid[IEEE80211_MAX_SSID_LEN];
-	u8 ssid_len, mesh_id_len, mesh_id_up_len;
 	struct cfg80211_conn *conn;
 	struct cfg80211_cached_keys *connect_keys;
 	enum ieee80211_bss_type conn_bss_type;
@@ -5598,20 +5609,17 @@ struct wireless_dev {
 	struct list_head event_list;
 	spinlock_t event_lock;
 
-	struct cfg80211_internal_bss *current_bss; /* associated / joined */
-	struct cfg80211_chan_def preset_chandef;
-	struct cfg80211_chan_def chandef;
+	u8 connected:1;
 
 	bool ps;
 	int ps_timeout;
 
-	int beacon_interval;
-
 	u32 ap_unexpected_nlportid;
 
 	u32 owner_nlportid;
 	bool nl_owner_dead;
 
+	/* FIXME: need to rework radar detection for MLO */
 	bool cac_started;
 	unsigned long cac_start_time;
 	unsigned int cac_time_ms;
@@ -5639,6 +5647,50 @@ struct wireless_dev {
 	struct work_struct pmsr_free_wk;
 
 	unsigned long unprot_beacon_reported;
+
+	union {
+		struct {
+			u8 connected_addr[ETH_ALEN] __aligned(2);
+			u8 ssid[IEEE80211_MAX_SSID_LEN];
+			u8 ssid_len;
+		} client;
+		struct {
+			int beacon_interval;
+			struct cfg80211_chan_def preset_chandef;
+			struct cfg80211_chan_def chandef;
+			u8 id[IEEE80211_MAX_SSID_LEN];
+			u8 id_len, id_up_len;
+		} mesh;
+		struct {
+			struct cfg80211_chan_def preset_chandef;
+			u8 ssid[IEEE80211_MAX_SSID_LEN];
+			u8 ssid_len;
+		} ap;
+		struct {
+			struct cfg80211_internal_bss *current_bss;
+			struct cfg80211_chan_def chandef;
+			int beacon_interval;
+			u8 ssid[IEEE80211_MAX_SSID_LEN];
+			u8 ssid_len;
+		} ibss;
+		struct {
+			struct cfg80211_chan_def chandef;
+		} ocb;
+	} u;
+
+	struct {
+		u8 addr[ETH_ALEN] __aligned(2);
+		union {
+			struct {
+				unsigned int beacon_interval;
+				struct cfg80211_chan_def chandef;
+			} ap;
+			struct {
+				struct cfg80211_internal_bss *current_bss;
+			} client;
+		};
+	} links[IEEE80211_MLD_MAX_NUM_LINKS];
+	u16 valid_links;
 };
 
 static inline const u8 *wdev_address(struct wireless_dev *wdev)
@@ -5668,6 +5720,31 @@ static inline void *wdev_priv(struct wireless_dev *wdev)
 }
 
 /**
+ * wdev_chandef - return chandef pointer from wireless_dev
+ * @wdev: the wdev
+ * @link_id: the link ID for MLO
+ *
+ * Return: The chandef depending on the mode, or %NULL.
+ */
+struct cfg80211_chan_def *wdev_chandef(struct wireless_dev *wdev,
+				       unsigned int link_id);
+
+static inline void WARN_INVALID_LINK_ID(struct wireless_dev *wdev,
+					unsigned int link_id)
+{
+	WARN_ON(link_id && !wdev->valid_links);
+	WARN_ON(wdev->valid_links &&
+		!(wdev->valid_links & BIT(link_id)));
+}
+
+#define for_each_valid_link(wdev, link_id)					\
+	for (link_id = 0;							\
+	     link_id < ((wdev)->valid_links ? ARRAY_SIZE((wdev)->links) : 1);	\
+	     link_id++)								\
+		if (!(wdev)->valid_links ||					\
+		    ((wdev)->valid_links & BIT(link_id)))
+
+/**
  * DOC: Utility functions
  *
  * cfg80211 offers a number of utility functions that can be useful.
@@ -7882,12 +7959,14 @@ bool cfg80211_reg_can_beacon_relax(struct wiphy *wiphy,
  * cfg80211_ch_switch_notify - update wdev channel and notify userspace
  * @dev: the device which switched channels
  * @chandef: the new channel definition
+ * @link_id: the link ID for MLO, must be 0 for non-MLO
  *
  * Caller must acquire wdev_lock, therefore must only be called from sleepable
  * driver context!
  */
 void cfg80211_ch_switch_notify(struct net_device *dev,
-			       struct cfg80211_chan_def *chandef);
+			       struct cfg80211_chan_def *chandef,
+			       unsigned int link_id);
 
 /*
  * cfg80211_ch_switch_started_notify - notify channel switch start
diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index 98f905f16411..a9a2c9fef295 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -324,6 +324,17 @@
  */
 
 /**
+ * DOC: Multi-Link Operation
+ *
+ * In Multi-Link Operation, a connection between to MLDs utilizes multiple
+ * links. To use this in nl80211, various commands and responses now need
+ * to or will include the new %NL80211_ATTR_MLO_LINKS attribute.
+ * Additionally, various commands that need to operate on a specific link
+ * now need to be given the %NL80211_ATTR_MLO_LINK_ID attribute, e.g. to
+ * use %NL80211_CMD_START_AP or similar functions.
+ */
+
+/**
  * enum nl80211_commands - supported nl80211 commands
  *
  * @NL80211_CMD_UNSPEC: unspecified command to catch errors
@@ -1237,6 +1248,12 @@
  *      to describe the BSSID address of the AP and %NL80211_ATTR_TIMEOUT to
  *      specify the timeout value.
  *
+ * @NL80211_CMD_ADD_LINK: Add a new link to an interface. The
+ *	%NL80211_ATTR_MLO_LINK_ID attribute is used for the new link.
+ * @NL80211_CMD_REMOVE_LINK: Remove a link from an interface. This may come
+ *	without %NL80211_ATTR_MLO_LINK_ID as an easy way to remove all links
+ *	in preparation for e.g. roaming to a regular (non-MLO) AP.
+ *
  * @NL80211_CMD_MAX: highest used command number
  * @__NL80211_CMD_AFTER_LAST: internal use
  */
@@ -1481,6 +1498,9 @@ enum nl80211_commands {
 
 	NL80211_CMD_ASSOC_COMEBACK,
 
+	NL80211_CMD_ADD_LINK,
+	NL80211_CMD_REMOVE_LINK,
+
 	/* add new commands above here */
 
 	/* used to define NL80211_CMD_MAX below */
@@ -2663,6 +2683,11 @@ enum nl80211_commands {
  *	association request when used with NL80211_CMD_NEW_STATION). Can be set
  *	only if %NL80211_STA_FLAG_WME is set.
  *
+ * @NL80211_ATTR_MLO_LINK_ID: A (u8) link ID for use with MLO, to be used with
+ *	various commands that need a link ID to operate.
+ * @NL80211_ATTR_MLO_LINKS: A nested array of links, each containing some
+ *	per-link information and a link ID.
+ *
  * @NUM_NL80211_ATTR: total number of nl80211_attrs available
  * @NL80211_ATTR_MAX: highest attribute number currently defined
  * @__NL80211_ATTR_AFTER_LAST: internal use
@@ -3177,6 +3202,9 @@ enum nl80211_attrs {
 
 	NL80211_ATTR_DISABLE_EHT,
 
+	NL80211_ATTR_MLO_LINKS,
+	NL80211_ATTR_MLO_LINK_ID,
+
 	/* add attributes here, update the policy in nl80211.c */
 
 	__NL80211_ATTR_AFTER_LAST,
diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index 881efbfb96f6..362cac9e2135 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -1342,7 +1342,8 @@ static void ieee80211_free_next_beacon(struct ieee80211_sub_if_data *sdata)
 	sdata->u.ap.next_beacon = NULL;
 }
 
-static int ieee80211_stop_ap(struct wiphy *wiphy, struct net_device *dev)
+static int ieee80211_stop_ap(struct wiphy *wiphy, struct net_device *dev,
+			     unsigned int link_id)
 {
 	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
 	struct ieee80211_sub_if_data *vlan;
@@ -3049,6 +3050,7 @@ static int ieee80211_set_cqm_rssi_range_config(struct wiphy *wiphy,
 
 static int ieee80211_set_bitrate_mask(struct wiphy *wiphy,
 				      struct net_device *dev,
+				      unsigned int link_id,
 				      const u8 *addr,
 				      const struct cfg80211_bitrate_mask *mask)
 {
@@ -3390,7 +3392,7 @@ static int __ieee80211_csa_finalize(struct ieee80211_sub_if_data *sdata)
 	if (err)
 		return err;
 
-	cfg80211_ch_switch_notify(sdata->dev, &sdata->csa_chandef);
+	cfg80211_ch_switch_notify(sdata->dev, &sdata->csa_chandef, 0);
 
 	return 0;
 }
@@ -3898,6 +3900,7 @@ unlock:
 
 static int ieee80211_cfg_get_channel(struct wiphy *wiphy,
 				     struct wireless_dev *wdev,
+				     unsigned int link_id,
 				     struct cfg80211_chan_def *chandef)
 {
 	struct ieee80211_sub_if_data *sdata = IEEE80211_WDEV_TO_SUB_IF(wdev);
@@ -3958,6 +3961,7 @@ static int ieee80211_set_qos_map(struct wiphy *wiphy,
 
 static int ieee80211_set_ap_chanwidth(struct wiphy *wiphy,
 				      struct net_device *dev,
+				      unsigned int link_id,
 				      struct cfg80211_chan_def *chandef)
 {
 	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(d