Merge tag '9p-for-5.20' of https://github.com/martinetd/linux

[linux-2.6-microblaze.git] / net / mac80211 / sta_info.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright 2002-2005, Instant802 Networks, Inc.
 * Copyright 2006-2007  Jiri Benc <jbenc@suse.cz>
 * Copyright 2013-2014  Intel Mobile Communications GmbH
 * Copyright (C) 2015 - 2017 Intel Deutschland GmbH
 * Copyright (C) 2018-2021 Intel Corporation
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/etherdevice.h>
#include <linux/netdevice.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/skbuff.h>
#include <linux/if_arp.h>
#include <linux/timer.h>
#include <linux/rtnetlink.h>

#include <net/codel.h>
#include <net/mac80211.h>
#include "ieee80211_i.h"
#include "driver-ops.h"
#include "rate.h"
#include "sta_info.h"
#include "debugfs_sta.h"
#include "mesh.h"
#include "wme.h"

/**
 * DOC: STA information lifetime rules
 *
 * STA info structures (&struct sta_info) are managed in a hash table
 * for faster lookup and a list for iteration. They are managed using
 * RCU, i.e. access to the list and hash table is protected by RCU.
 *
 * Upon allocating a STA info structure with sta_info_alloc(), the caller
 * owns that structure. It must then insert it into the hash table using
 * either sta_info_insert() or sta_info_insert_rcu(); only in the latter
 * case (which acquires an rcu read section but must not be called from
 * within one) will the pointer still be valid after the call. Note that
 * the caller may not do much with the STA info before inserting it, in
 * particular, it may not start any mesh peer link management or add
 * encryption keys.
 *
 * When the insertion fails (sta_info_insert()) returns non-zero), the
 * structure will have been freed by sta_info_insert()!
 *
 * Station entries are added by mac80211 when you establish a link with a
 * peer. This means different things for the different type of interfaces
 * we support. For a regular station this mean we add the AP sta when we
 * receive an association response from the AP. For IBSS this occurs when
 * get to know about a peer on the same IBSS. For WDS we add the sta for
 * the peer immediately upon device open. When using AP mode we add stations
 * for each respective station upon request from userspace through nl80211.
 *
 * In order to remove a STA info structure, various sta_info_destroy_*()
 * calls are available.
 *
 * There is no concept of ownership on a STA entry, each structure is
 * owned by the global hash table/list until it is removed. All users of
 * the structure need to be RCU protected so that the structure won't be
 * freed before they are done using it.
 */

struct sta_link_alloc {
        struct link_sta_info info;
        struct ieee80211_link_sta sta;
        struct rcu_head rcu_head;
};

static const struct rhashtable_params sta_rht_params = {
        .nelem_hint = 3, /* start small */
        .automatic_shrinking = true,
        .head_offset = offsetof(struct sta_info, hash_node),
        .key_offset = offsetof(struct sta_info, addr),
        .key_len = ETH_ALEN,
        .max_size = CONFIG_MAC80211_STA_HASH_MAX_SIZE,
};

static const struct rhashtable_params link_sta_rht_params = {
        .nelem_hint = 3, /* start small */
        .automatic_shrinking = true,
        .head_offset = offsetof(struct link_sta_info, link_hash_node),
        .key_offset = offsetof(struct link_sta_info, addr),
        .key_len = ETH_ALEN,
        .max_size = CONFIG_MAC80211_STA_HASH_MAX_SIZE,
};

/* Caller must hold local->sta_mtx */
static int sta_info_hash_del(struct ieee80211_local *local,
                             struct sta_info *sta)
{
        return rhltable_remove(&local->sta_hash, &sta->hash_node,
                               sta_rht_params);
}

static int link_sta_info_hash_add(struct ieee80211_local *local,
                                  struct link_sta_info *link_sta)
{
        lockdep_assert_held(&local->sta_mtx);
        return rhltable_insert(&local->link_sta_hash,
                               &link_sta->link_hash_node,
                               link_sta_rht_params);
}

static int link_sta_info_hash_del(struct ieee80211_local *local,
                                  struct link_sta_info *link_sta)
{
        lockdep_assert_held(&local->sta_mtx);
        return rhltable_remove(&local->link_sta_hash,
                               &link_sta->link_hash_node,
                               link_sta_rht_params);
}

static void __cleanup_single_sta(struct sta_info *sta)
{
        int ac, i;
        struct tid_ampdu_tx *tid_tx;
        struct ieee80211_sub_if_data *sdata = sta->sdata;
        struct ieee80211_local *local = sdata->local;
        struct ps_data *ps;

        if (test_sta_flag(sta, WLAN_STA_PS_STA) ||
            test_sta_flag(sta, WLAN_STA_PS_DRIVER) ||
            test_sta_flag(sta, WLAN_STA_PS_DELIVER)) {
                if (sta->sdata->vif.type == NL80211_IFTYPE_AP ||
                    sta->sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
                        ps = &sdata->bss->ps;
                else if (ieee80211_vif_is_mesh(&sdata->vif))
                        ps = &sdata->u.mesh.ps;
                else
                        return;

                clear_sta_flag(sta, WLAN_STA_PS_STA);
                clear_sta_flag(sta, WLAN_STA_PS_DRIVER);
                clear_sta_flag(sta, WLAN_STA_PS_DELIVER);

                atomic_dec(&ps->num_sta_ps);
        }

        if (sta->sta.txq[0]) {
                for (i = 0; i < ARRAY_SIZE(sta->sta.txq); i++) {
                        struct txq_info *txqi;

                        if (!sta->sta.txq[i])
                                continue;

                        txqi = to_txq_info(sta->sta.txq[i]);

                        ieee80211_txq_purge(local, txqi);
                }
        }

        for (ac = 0; ac < IEEE80211_NUM_ACS; ac++) {
                local->total_ps_buffered -= skb_queue_len(&sta->ps_tx_buf[ac]);
                ieee80211_purge_tx_queue(&local->hw, &sta->ps_tx_buf[ac]);
                ieee80211_purge_tx_queue(&local->hw, &sta->tx_filtered[ac]);
        }

        if (ieee80211_vif_is_mesh(&sdata->vif))
                mesh_sta_cleanup(sta);

        cancel_work_sync(&sta->drv_deliver_wk);

        /*
         * Destroy aggregation state here. It would be nice to wait for the
         * driver to finish aggregation stop and then clean up, but for now
         * drivers have to handle aggregation stop being requested, followed
         * directly by station destruction.
         */
        for (i = 0; i < IEEE80211_NUM_TIDS; i++) {
                kfree(sta->ampdu_mlme.tid_start_tx[i]);
                tid_tx = rcu_dereference_raw(sta->ampdu_mlme.tid_tx[i]);
                if (!tid_tx)
                        continue;
                ieee80211_purge_tx_queue(&local->hw, &tid_tx->pending);
                kfree(tid_tx);
        }
}

static void cleanup_single_sta(struct sta_info *sta)
{
        struct ieee80211_sub_if_data *sdata = sta->sdata;
        struct ieee80211_local *local = sdata->local;

        __cleanup_single_sta(sta);
        sta_info_free(local, sta);
}

struct rhlist_head *sta_info_hash_lookup(struct ieee80211_local *local,
                                         const u8 *addr)
{
        return rhltable_lookup(&local->sta_hash, addr, sta_rht_params);
}

/* protected by RCU */
struct sta_info *sta_info_get(struct ieee80211_sub_if_data *sdata,
                              const u8 *addr)
{
        struct ieee80211_local *local = sdata->local;
        struct rhlist_head *tmp;
        struct sta_info *sta;

        rcu_read_lock();
        for_each_sta_info(local, addr, sta, tmp) {
                if (sta->sdata == sdata) {
                        rcu_read_unlock();
                        /* this is safe as the caller must already hold
                         * another rcu read section or the mutex
                         */
                        return sta;
                }
        }
        rcu_read_unlock();
        return NULL;
}

/*
 * Get sta info either from the specified interface
 * or from one of its vlans
 */
struct sta_info *sta_info_get_bss(struct ieee80211_sub_if_data *sdata,
                                  const u8 *addr)
{
        struct ieee80211_local *local = sdata->local;
        struct rhlist_head *tmp;
        struct sta_info *sta;

        rcu_read_lock();
        for_each_sta_info(local, addr, sta, tmp) {
                if (sta->sdata == sdata ||
                    (sta->sdata->bss && sta->sdata->bss == sdata->bss)) {
                        rcu_read_unlock();
                        /* this is safe as the caller must already hold
                         * another rcu read section or the mutex
                         */
                        return sta;
                }
        }
        rcu_read_unlock();
        return NULL;
}

struct rhlist_head *link_sta_info_hash_lookup(struct ieee80211_local *local,
                                              const u8 *addr)
{
        return rhltable_lookup(&local->link_sta_hash, addr,
                               link_sta_rht_params);
}

struct link_sta_info *
link_sta_info_get_bss(struct ieee80211_sub_if_data *sdata, const u8 *addr)
{
        struct ieee80211_local *local = sdata->local;
        struct rhlist_head *tmp;
        struct link_sta_info *link_sta;

        rcu_read_lock();
        for_each_link_sta_info(local, addr, link_sta, tmp) {
                struct sta_info *sta = link_sta->sta;

                if (sta->sdata == sdata ||
                    (sta->sdata->bss && sta->sdata->bss == sdata->bss)) {
                        rcu_read_unlock();
                        /* this is safe as the caller must already hold
                         * another rcu read section or the mutex
                         */
                        return link_sta;
                }
        }
        rcu_read_unlock();
        return NULL;
}

struct sta_info *sta_info_get_by_addrs(struct ieee80211_local *local,
                                       const u8 *sta_addr, const u8 *vif_addr)
{
        struct rhlist_head *tmp;
        struct sta_info *sta;

        for_each_sta_info(local, sta_addr, sta, tmp) {
                if (ether_addr_equal(vif_addr, sta->sdata->vif.addr))
                        return sta;
        }

        return NULL;
}

struct sta_info *sta_info_get_by_idx(struct ieee80211_sub_if_data *sdata,
                                     int idx)
{
        struct ieee80211_local *local = sdata->local;
        struct sta_info *sta;
        int i = 0;

        list_for_each_entry_rcu(sta, &local->sta_list, list,
                                lockdep_is_held(&local->sta_mtx)) {
                if (sdata != sta->sdata)
                        continue;
                if (i < idx) {
                        ++i;
                        continue;
                }
                return sta;
        }

        return NULL;
}

static void sta_info_free_link(struct link_sta_info *link_sta)
{
        free_percpu(link_sta->pcpu_rx_stats);
}

static void sta_remove_link(struct sta_info *sta, unsigned int link_id,
                            bool unhash)
{
        struct sta_link_alloc *alloc = NULL;
        struct link_sta_info *link_sta;

        link_sta = rcu_dereference_protected(sta->link[link_id],
                                             lockdep_is_held(&sta->local->sta_mtx));

        if (WARN_ON(!link_sta))
                return;

        if (unhash)
                link_sta_info_hash_del(sta->local, link_sta);

        if (link_sta != &sta->deflink)
                alloc = container_of(link_sta, typeof(*alloc), info);

        sta->sta.valid_links &= ~BIT(link_id);
        RCU_INIT_POINTER(sta->link[link_id], NULL);
        RCU_INIT_POINTER(sta->sta.link[link_id], NULL);
        if (alloc) {
                sta_info_free_link(&alloc->info);
                kfree_rcu(alloc, rcu_head);
        }
}

/**
 * sta_info_free - free STA
 *
 * @local: pointer to the global information
 * @sta: STA info to free
 *
 * This function must undo everything done by sta_info_alloc()
 * that may happen before sta_info_insert(). It may only be
 * called when sta_info_insert() has not been attempted (and
 * if that fails, the station is freed anyway.)
 */
void sta_info_free(struct ieee80211_local *local, struct sta_info *sta)
{
        int i;

        for (i = 0; i < ARRAY_SIZE(sta->link); i++) {
                if (!(sta->sta.valid_links & BIT(i)))
                        continue;

                sta_remove_link(sta, i, false);
        }

        /*
         * If we had used sta_info_pre_move_state() then we might not
         * have gone through the state transitions down again, so do
         * it here now (and warn if it's inserted).
         *
         * This will clear state such as fast TX/RX that may have been
         * allocated during state transitions.
         */
        while (sta->sta_state > IEEE80211_STA_NONE) {
                int ret;

                WARN_ON_ONCE(test_sta_flag(sta, WLAN_STA_INSERTED));

                ret = sta_info_move_state(sta, sta->sta_state - 1);
                if (WARN_ONCE(ret, "sta_info_move_state() returned %d\n", ret))
                        break;
        }

        if (sta->rate_ctrl)
                rate_control_free_sta(sta);

        sta_dbg(sta->sdata, "Destroyed STA %pM\n", sta->sta.addr);

        if (sta->sta.txq[0])
                kfree(to_txq_info(sta->sta.txq[0]));
        kfree(rcu_dereference_raw(sta->sta.rates));
#ifdef CONFIG_MAC80211_MESH
        kfree(sta->mesh);
#endif

        sta_info_free_link(&sta->deflink);
        kfree(sta);
}

/* Caller must hold local->sta_mtx */
static int sta_info_hash_add(struct ieee80211_local *local,
                             struct sta_info *sta)
{
        return rhltable_insert(&local->sta_hash, &sta->hash_node,
                               sta_rht_params);
}

static void sta_deliver_ps_frames(struct work_struct *wk)
{
        struct sta_info *sta;

        sta = container_of(wk, struct sta_info, drv_deliver_wk);

        if (sta->dead)
                return;

        local_bh_disable();
        if (!test_sta_flag(sta, WLAN_STA_PS_STA))
                ieee80211_sta_ps_deliver_wakeup(sta);
        else if (test_and_clear_sta_flag(sta, WLAN_STA_PSPOLL))
                ieee80211_sta_ps_deliver_poll_response(sta);
        else if (test_and_clear_sta_flag(sta, WLAN_STA_UAPSD))
                ieee80211_sta_ps_deliver_uapsd(sta);
        local_bh_enable();
}

static int sta_prepare_rate_control(struct ieee80211_local *local,
                                    struct sta_info *sta, gfp_t gfp)
{
        if (ieee80211_hw_check(&local->hw, HAS_RATE_CONTROL))
                return 0;

        sta->rate_ctrl = local->rate_ctrl;
        sta->rate_ctrl_priv = rate_control_alloc_sta(sta->rate_ctrl,
                                                     sta, gfp);
        if (!sta->rate_ctrl_priv)
                return -ENOMEM;

        return 0;
}

static int sta_info_alloc_link(struct ieee80211_local *local,
                               struct link_sta_info *link_info,
                               gfp_t gfp)
{
        struct ieee80211_hw *hw = &local->hw;
        int i;

        if (ieee80211_hw_check(hw, USES_RSS)) {
                link_info->pcpu_rx_stats =
                        alloc_percpu_gfp(struct ieee80211_sta_rx_stats, gfp);
                if (!link_info->pcpu_rx_stats)
                        return -ENOMEM;
        }

        link_info->rx_stats.last_rx = jiffies;
        u64_stats_init(&link_info->rx_stats.syncp);

        ewma_signal_init(&link_info->rx_stats_avg.signal);
        ewma_avg_signal_init(&link_info->status_stats.avg_ack_signal);
        for (i = 0; i < ARRAY_SIZE(link_info->rx_stats_avg.chain_signal); i++)
                ewma_signal_init(&link_info->rx_stats_avg.chain_signal[i]);

        return 0;
}

static void sta_info_add_link(struct sta_info *sta,
                              unsigned int link_id,
                              struct link_sta_info *link_info,
                              struct ieee80211_link_sta *link_sta)
{
        link_info->sta = sta;
        link_info->link_id = link_id;
        link_info->pub = link_sta;
        rcu_assign_pointer(sta->link[link_id], link_info);
        rcu_assign_pointer(sta->sta.link[link_id], link_sta);
}

static struct sta_info *
__sta_info_alloc(struct ieee80211_sub_if_data *sdata,
                 const u8 *addr, int link_id, const u8 *link_addr,
                 gfp_t gfp)
{
        struct ieee80211_local *local = sdata->local;
        struct ieee80211_hw *hw = &local->hw;
        struct sta_info *sta;
        int i;

        sta = kzalloc(sizeof(*sta) + hw->sta_data_size, gfp);
        if (!sta)
                return NULL;

        sta->local = local;
        sta->sdata = sdata;

        if (sta_info_alloc_link(local, &sta->deflink, gfp))
                return NULL;

        if (link_id >= 0) {
                sta_info_add_link(sta, link_id, &sta->deflink,
                                  &sta->sta.deflink);
                sta->sta.valid_links = BIT(link_id);
        } else {
                sta_info_add_link(sta, 0, &sta->deflink, &sta->sta.deflink);
        }

        spin_lock_init(&sta->lock);
        spin_lock_init(&sta->ps_lock);
        INIT_WORK(&sta->drv_deliver_wk, sta_deliver_ps_frames);
        INIT_WORK(&sta->ampdu_mlme.work, ieee80211_ba_session_work);
        mutex_init(&sta->ampdu_mlme.mtx);
#ifdef CONFIG_MAC80211_MESH
        if (ieee80211_vif_is_mesh(&sdata->vif)) {
                sta->mesh = kzalloc(sizeof(*sta->mesh), gfp);
                if (!sta->mesh)
                        goto free;
                sta->mesh->plink_sta = sta;
                spin_lock_init(&sta->mesh->plink_lock);
                if (!sdata->u.mesh.user_mpm)
                        timer_setup(&sta->mesh->plink_timer, mesh_plink_timer,
                                    0);
                sta->mesh->nonpeer_pm = NL80211_MESH_POWER_ACTIVE;
        }
#endif

        memcpy(sta->addr, addr, ETH_ALEN);
        memcpy(sta->sta.addr, addr, ETH_ALEN);
        memcpy(sta->deflink.addr, link_addr, ETH_ALEN);
        memcpy(sta->sta.deflink.addr, link_addr, ETH_ALEN);
        sta->sta.max_rx_aggregation_subframes =
                local->hw.max_rx_aggregation_subframes;

        /* TODO link specific alloc and assignments for MLO Link STA */

        /* Extended Key ID needs to install keys for keyid 0 and 1 Rx-only.
         * The Tx path starts to use a key as soon as the key slot ptk_idx
         * references to is not NULL. To not use the initial Rx-only key
         * prematurely for Tx initialize ptk_idx to an impossible PTK keyid
         * which always will refer to a NULL key.
         */
        BUILD_BUG_ON(ARRAY_SIZE(sta->ptk) <= INVALID_PTK_KEYIDX);
        sta->ptk_idx = INVALID_PTK_KEYIDX;


        ieee80211_init_frag_cache(&sta->frags);

        sta->sta_state = IEEE80211_STA_NONE;

        /* Mark TID as unreserved */
        sta->reserved_tid = IEEE80211_TID_UNRESERVED;

        sta->last_connected = ktime_get_seconds();

        if (local->ops->wake_tx_queue) {
                void *txq_data;
                int size = sizeof(struct txq_info) +
                           ALIGN(hw->txq_data_size, sizeof(void *));

                txq_data = kcalloc(ARRAY_SIZE(sta->sta.txq), size, gfp);
                if (!txq_data)
                        goto free;

                for (i = 0; i < ARRAY_SIZE(sta->sta.txq); i++) {
                        struct txq_info *txq = txq_data + i * size;

                        /* might not do anything for the bufferable MMPDU TXQ */
                        ieee80211_txq_init(sdata, sta, txq, i);
                }
        }

        if (sta_prepare_rate_control(local, sta, gfp))
                goto free_txq;

        sta->airtime_weight = IEEE80211_DEFAULT_AIRTIME_WEIGHT;

        for (i = 0; i < IEEE80211_NUM_ACS; i++) {
                skb_queue_head_init(&sta->ps_tx_buf[i]);
                skb_queue_head_init(&sta->tx_filtered[i]);
                sta->airtime[i].deficit = sta->airtime_weight;
                atomic_set(&sta->airtime[i].aql_tx_pending, 0);
                sta->airtime[i].aql_limit_low = local->aql_txq_limit_low[i];
                sta->airtime[i].aql_limit_high = local->aql_txq_limit_high[i];
        }

        for (i = 0; i < IEEE80211_NUM_TIDS; i++)
                sta->last_seq_ctrl[i] = cpu_to_le16(USHRT_MAX);

        for (i = 0; i < NUM_NL80211_BANDS; i++) {
                u32 mandatory = 0;
                int r;

                if (!hw->wiphy->bands[i])
                        continue;

                switch (i) {
                case NL80211_BAND_2GHZ:
                case NL80211_BAND_LC:
                        /*
                         * We use both here, even if we cannot really know for
                         * sure the station will support both, but the only use
                         * for this is when we don't know anything yet and send
                         * management frames, and then we'll pick the lowest
                         * possible rate anyway.
                         * If we don't include _G here, we cannot find a rate
                         * in P2P, and thus trigger the WARN_ONCE() in rate.c
                         */
                        mandatory = IEEE80211_RATE_MANDATORY_B |
                                    IEEE80211_RATE_MANDATORY_G;
                        break;
                case NL80211_BAND_5GHZ:
                        mandatory = IEEE80211_RATE_MANDATORY_A;
                        break;
                case NL80211_BAND_60GHZ:
                        WARN_ON(1);
                        mandatory = 0;
                        break;
                }

                for (r = 0; r < hw->wiphy->bands[i]->n_bitrates; r++) {
                        struct ieee80211_rate *rate;

                        rate = &hw->wiphy->bands[i]->bitrates[r];

                        if (!(rate->flags & mandatory))
                                continue;
                        sta->sta.deflink.supp_rates[i] |= BIT(r);
                }
        }

        sta->sta.smps_mode = IEEE80211_SMPS_OFF;
        sta->sta.max_rc_amsdu_len = IEEE80211_MAX_MPDU_LEN_HT_BA;

        sta->cparams.ce_threshold = CODEL_DISABLED_THRESHOLD;
        sta->cparams.target = MS2TIME(20);
        sta->cparams.interval = MS2TIME(100);
        sta->cparams.ecn = true;
        sta->cparams.ce_threshold_selector = 0;
        sta->cparams.ce_threshold_mask = 0;

        sta_dbg(sdata, "Allocated STA %pM\n", sta->sta.addr);

        return sta;

free_txq:
        if (sta->sta.txq[0])
                kfree(to_txq_info(sta->sta.txq[0]));
free:
        sta_info_free_link(&sta->deflink);
#ifdef CONFIG_MAC80211_MESH
        kfree(sta->mesh);
#endif
        kfree(sta);
        return NULL;
}

struct sta_info *sta_info_alloc(struct ieee80211_sub_if_data *sdata,
                                const u8 *addr, gfp_t gfp)
{
        return __sta_info_alloc(sdata, addr, -1, addr, gfp);
}

struct sta_info *sta_info_alloc_with_link(struct ieee80211_sub_if_data *sdata,
                                          const u8 *mld_addr,
                                          unsigned int link_id,
                                          const u8 *link_addr,
                                          gfp_t gfp)
{
        return __sta_info_alloc(sdata, mld_addr, link_id, link_addr, gfp);
}

static int sta_info_insert_check(struct sta_info *sta)
{
        struct ieee80211_sub_if_data *sdata = sta->sdata;

        /*
         * Can't be a WARN_ON because it can be triggered through a race:
         * something inserts a STA (on one CPU) without holding the RTNL
         * and another CPU turns off the net device.
         */
        if (unlikely(!ieee80211_sdata_running(sdata)))
                return -ENETDOWN;

        if (WARN_ON(ether_addr_equal(sta->sta.addr, sdata->vif.addr) ||
                    !is_valid_ether_addr(sta->sta.addr)))
                return -EINVAL;

        /* The RCU read lock is required by rhashtable due to
         * asynchronous resize/rehash.  We also require the mutex
         * for correctness.
         */
        rcu_read_lock();
        lockdep_assert_held(&sdata->local->sta_mtx);
        if (ieee80211_hw_check(&sdata->local->hw, NEEDS_UNIQUE_STA_ADDR) &&
            ieee80211_find_sta_by_ifaddr(&sdata->local->hw, sta->addr, NULL)) {
                rcu_read_unlock();
                return -ENOTUNIQ;
        }
        rcu_read_unlock();

        return 0;
}

static int sta_info_insert_drv_state(struct ieee80211_local *local,
                                     struct ieee80211_sub_if_data *sdata,
                                     struct sta_info *sta)
{
        enum ieee80211_sta_state state;
        int err = 0;

        for (state = IEEE80211_STA_NOTEXIST; state < sta->sta_state; state++) {
                err = drv_sta_state(local, sdata, sta, state, state + 1);
                if (err)
                        break;
        }

        if (!err) {
                /*
                 * Drivers using legacy sta_add/sta_remove callbacks only
                 * get uploaded set to true after sta_add is called.
                 */
                if (!local->ops->sta_add)
                        sta->uploaded = true;
                return 0;
        }

        if (sdata->vif.type == NL80211_IFTYPE_ADHOC) {
                sdata_info(sdata,
                           "failed to move IBSS STA %pM to state %d (%d) - keeping it anyway\n",
                           sta->sta.addr, state + 1, err);
                err = 0;
        }

        /* unwind on error */
        for (; state > IEEE80211_STA_NOTEXIST; state--)
                WARN_ON(drv_sta_state(local, sdata, sta, state, state - 1));

        return err;
}

static void
ieee80211_recalc_p2p_go_ps_allowed(struct ieee80211_sub_if_data *sdata)
{
        struct ieee80211_local *local = sdata->local;
        bool allow_p2p_go_ps = sdata->vif.p2p;
        struct sta_info *sta;

        rcu_read_lock();
        list_for_each_entry_rcu(sta, &local->sta_list, list) {
                if (sdata != sta->sdata ||
                    !test_sta_flag(sta, WLAN_STA_ASSOC))
                        continue;
                if (!sta->sta.support_p2p_ps) {
                        allow_p2p_go_ps = false;
                        break;
                }
        }
        rcu_read_unlock();

        if (allow_p2p_go_ps != sdata->vif.bss_conf.allow_p2p_go_ps) {
                sdata->vif.bss_conf.allow_p2p_go_ps = allow_p2p_go_ps;
                ieee80211_link_info_change_notify(sdata, &sdata->deflink,
                                                  BSS_CHANGED_P2P_PS);
        }
}

/*
 * should be called with sta_mtx locked
 * this function replaces the mutex lock
 * with a RCU lock
 */
static int sta_info_insert_finish(struct sta_info *sta) __acquires(RCU)
{
        struct ieee80211_local *local = sta->local;
        struct ieee80211_sub_if_data *sdata = sta->sdata;
        struct station_info *sinfo = NULL;
        int err = 0;

        lockdep_assert_held(&local->sta_mtx);

        /* check if STA exists already */
        if (sta_info_get_bss(sdata, sta->sta.addr)) {
                err = -EEXIST;
                goto out_cleanup;
        }

        sinfo = kzalloc(sizeof(struct station_info), GFP_KERNEL);
        if (!sinfo) {
                err = -ENOMEM;
                goto out_cleanup;
        }

        local->num_sta++;
        local->sta_generation++;
        smp_mb();

        /* simplify things and don't accept BA sessions yet */
        set_sta_flag(sta, WLAN_STA_BLOCK_BA);

        /* make the station visible */
        err = sta_info_hash_add(local, sta);
        if (err)
                goto out_drop_sta;

        if (sta->sta.valid_links) {
                err = link_sta_info_hash_add(local, &sta->deflink);
                if (err) {
                        sta_info_hash_del(local, sta);
                        goto out_drop_sta;
                }
        }

        list_add_tail_rcu(&sta->list, &local->sta_list);

        /* update channel context before notifying the driver about state
         * change, this enables driver using the updated channel context right away.
         */
        if (sta->sta_state >= IEEE80211_STA_ASSOC) {
                ieee80211_recalc_min_chandef(sta->sdata, -1);
                if (!sta->sta.support_p2p_ps)
                        ieee80211_recalc_p2p_go_ps_allowed(sta->sdata);
        }

        /* notify driver */
        err = sta_info_insert_drv_state(local, sdata, sta);
        if (err)
                goto out_remove;

        set_sta_flag(sta, WLAN_STA_INSERTED);

        /* accept BA sessions now */
        clear_sta_flag(sta, WLAN_STA_BLOCK_BA);

        ieee80211_sta_debugfs_add(sta);
        rate_control_add_sta_debugfs(sta);

        sinfo->generation = local->sta_generation;
        cfg80211_new_sta(sdata->dev, sta->sta.addr, sinfo, GFP_KERNEL);
        kfree(sinfo);

        sta_dbg(sdata, "Inserted STA %pM\n", sta->sta.addr);

        /* move reference to rcu-protected */
        rcu_read_lock();
        mutex_unlock(&local->sta_mtx);

        if (ieee80211_vif_is_mesh(&sdata->vif))
                mesh_accept_plinks_update(sdata);

        return 0;
 out_remove:
        if (sta->sta.valid_links)
                link_sta_info_hash_del(local, &sta->deflink);
        sta_info_hash_del(local, sta);
        list_del_rcu(&sta->list);
 out_drop_sta:
        local->num_sta--;
        synchronize_net();
 out_cleanup:
        cleanup_single_sta(sta);
        mutex_unlock(&local->sta_mtx);
        kfree(sinfo);
        rcu_read_lock();
        return err;
}

int sta_info_insert_rcu(struct sta_info *sta) __acquires(RCU)
{
        struct ieee80211_local *local = sta->local;
        int err;

        might_sleep();

        mutex_lock(&local->sta_mtx);

        err = sta_info_insert_check(sta);
        if (err) {
                sta_info_free(local, sta);
                mutex_unlock(&local->sta_mtx);
                rcu_read_lock();
                return err;
        }

        return sta_info_insert_finish(sta);
}

int sta_info_insert(struct sta_info *sta)
{
        int err = sta_info_insert_rcu(sta);

        rcu_read_unlock();

        return err;
}

static inline void __bss_tim_set(u8 *tim, u16 id)
{
        /*
         * This format has been mandated by the IEEE specifications,
         * so this line may not be changed to use the __set_bit() format.
         */
        tim[id / 8] |= (1 << (id % 8));
}

static inline void __bss_tim_clear(u8 *tim, u16 id)
{
        /*
         * This format has been mandated by the IEEE specifications,
         * so this line may not be changed to use the __clear_bit() format.
         */
        tim[id / 8] &= ~(1 << (id % 8));
}

static inline bool __bss_tim_get(u8 *tim, u16 id)
{
        /*
         * This format has been mandated by the IEEE specifications,
         * so this line may not be changed to use the test_bit() format.
         */
        return tim[id / 8] & (1 << (id % 8));
}

static unsigned long ieee80211_tids_for_ac(int ac)
{
        /* If we ever support TIDs > 7, this obviously needs to be adjusted */
        switch (ac) {
        case IEEE80211_AC_VO:
                return BIT(6) | BIT(7);
        case IEEE80211_AC_VI:
                return BIT(4) | BIT(5);
        case IEEE80211_AC_BE:
                return BIT(0) | BIT(3);
        case IEEE80211_AC_BK:
                return BIT(1) | BIT(2);
        default:
                WARN_ON(1);
                return 0;
        }
}

static void __sta_info_recalc_tim(struct sta_info *sta, bool ignore_pending)
{
        struct ieee80211_local *local = sta->local;
        struct ps_data *ps;
        bool indicate_tim = false;
        u8 ignore_for_tim = sta->sta.uapsd_queues;
        int ac;
        u16 id = sta->sta.aid;

        if (sta->sdata->vif.type == NL80211_IFTYPE_AP ||
            sta->sdata->vif.type == NL80211_IFTYPE_AP_VLAN) {
                if (WARN_ON_ONCE(!sta->sdata->bss))
                        return;

                ps = &sta->sdata->bss->ps;
#ifdef CONFIG_MAC80211_MESH
        } else if (ieee80211_vif_is_mesh(&sta->sdata->vif)) {
                ps = &sta->sdata->u.mesh.ps;
#endif
        } else {
                return;
        }

        /* No need to do anything if the driver does all */
        if (ieee80211_hw_check(&local->hw, AP_LINK_PS) && !local->ops->set_tim)
                return;

        if (sta->dead)
                goto done;

        /*
         * If all ACs are delivery-enabled then we should build
         * the TIM bit for all ACs anyway; if only some are then
         * we ignore those and build the TIM bit using only the
         * non-enabled ones.
         */
        if (ignore_for_tim == BIT(IEEE80211_NUM_ACS) - 1)
                ignore_for_tim = 0;

        if (ignore_pending)
                ignore_for_tim = BIT(IEEE80211_NUM_ACS) - 1;

        for (ac = 0; ac < IEEE80211_NUM_ACS; ac++) {
                unsigned long tids;

                if (ignore_for_tim & ieee80211_ac_to_qos_mask[ac])
                        continue;

                indicate_tim |= !skb_queue_empty(&sta->tx_filtered[ac]) ||
                                !skb_queue_empty(&sta->ps_tx_buf[ac]);
                if (indicate_tim)
                        break;

                tids = ieee80211_tids_for_ac(ac);

                indicate_tim |=
                        sta->driver_buffered_tids & tids;
                indicate_tim |=
                        sta->txq_buffered_tids & tids;
        }

 done:
        spin_lock_bh(&local->tim_lock);

        if (indicate_tim == __bss_tim_get(ps->tim, id))
                goto out_unlock;

        if (indicate_tim)
                __bss_tim_set(ps->tim, id);
        else
                __bss_tim_clear(ps->tim, id);

        if (local->ops->set_tim && !WARN_ON(sta->dead)) {
                local->tim_in_locked_section = true;
                drv_set_tim(local, &sta->sta, indicate_tim);
                local->tim_in_locked_section = false;
        }

out_unlock:
        spin_unlock_bh(&local->tim_lock);
}

void sta_info_recalc_tim(struct sta_info *sta)
{
        __sta_info_recalc_tim(sta, false);
}

static bool sta_info_buffer_expired(struct sta_info *sta, struct sk_buff *skb)
{
        struct ieee80211_tx_info *info;
        int timeout;

        if (!skb)
                return false;

        info = IEEE80211_SKB_CB(skb);

        /* Timeout: (2 * listen_interval * beacon_int * 1024 / 1000000) sec */
        timeout = (sta->listen_interval *
                   sta->sdata->vif.bss_conf.beacon_int *
                   32 / 15625) * HZ;
        if (timeout < STA_TX_BUFFER_EXPIRE)
                timeout = STA_TX_BUFFER_EXPIRE;
        return time_after(jiffies, info->control.jiffies + timeout);
}


static bool sta_info_cleanup_expire_buffered_ac(struct ieee80211_local *local,
                                                struct sta_info *sta, int ac)
{
        unsigned long flags;
        struct sk_buff *skb;

        /*
         * First check for frames that should expire on the filtered
         * queue. Frames here were rejected by the driver and are on
         * a separate queue to avoid reordering with normal PS-buffered
         * frames. They also aren't accounted for right now in the
         * total_ps_buffered counter.
         */
        for (;;) {
                spin_lock_irqsave(&sta->tx_filtered[ac].lock, flags);
                skb = skb_peek(&sta->tx_filtered[ac]);
                if (sta_info_buffer_expired(sta, skb))
                        skb = __skb_dequeue(&sta->tx_filtered[ac]);
                else
                        skb = NULL;
                spin_unlock_irqrestore(&sta->tx_filtered[ac].lock, flags);

                /*
                 * Frames are queued in order, so if this one
                 * hasn't expired yet we can stop testing. If
                 * we actually reached the end of the queue we
                 * also need to stop, of course.
                 */
                if (!skb)
                        break;
                ieee80211_free_txskb(&local->hw, skb);
        }

        /*
         * Now also check the normal PS-buffered queue, this will
         * only find something if the filtered queue was emptied
         * since the filtered frames are all before the normal PS
         * buffered frames.
         */
        for (;;) {
                spin_lock_irqsave(&sta->ps_tx_buf[ac].lock, flags);
                skb = skb_peek(&sta->ps_tx_buf[ac]);
                if (sta_info_buffer_expired(sta, skb))
                        skb = __skb_dequeue(&sta->ps_tx_buf[ac]);
                else
                        skb = NULL;
                spin_unlock_irqrestore(&sta->ps_tx_buf[ac].lock, flags);

                /*
                 * frames are queued in order, so if this one
                 * hasn't expired yet (or we reached the end of
                 * the queue) we can stop testing
                 */
                if (!skb)
                        break;

                local->total_ps_buffered--;
                ps_dbg(sta->sdata, "Buffered frame expired (STA %pM)\n",
                       sta->sta.addr);
                ieee80211_free_txskb(&local->hw, skb);
        }

        /*
         * Finally, recalculate the TIM bit for this station -- it might
         * now be clear because the station was too slow to retrieve its
         * frames.
         */
        sta_info_recalc_tim(sta);

        /*
         * Return whether there are any frames still buffered, this is
         * used to check whether the cleanup timer still needs to run,
         * if there are no frames we don't need to rearm the timer.
         */
        return !(skb_queue_empty(&sta->ps_tx_buf[ac]) &&
                 skb_queue_empty(&sta->tx_filtered[ac]));
}

static bool sta_info_cleanup_expire_buffered(struct ieee80211_local *local,
                                             struct sta_info *sta)
{
        bool have_buffered = false;
        int ac;

        /* This is only necessary for stations on BSS/MBSS interfaces */
        if (!sta->sdata->bss &&
            !ieee80211_vif_is_mesh(&sta->sdata->vif))
                return false;

        for (ac = 0; ac < IEEE80211_NUM_ACS; ac++)
                have_buffered |=
                        sta_info_cleanup_expire_buffered_ac(local, sta, ac);

        return have_buffered;
}

static int __must_check __sta_info_destroy_part1(struct sta_info *sta)
{
        struct ieee80211_local *local;
        struct ieee80211_sub_if_data *sdata;
        int ret, i;

        might_sleep();

        if (!sta)
                return -ENOENT;

        local = sta->local;
        sdata = sta->sdata;

        lockdep_assert_held(&local->sta_mtx);

        /*
         * Before removing the station from the driver and
         * rate control, it might still start new aggregation
         * sessions -- block that to make sure the tear-down
         * will be sufficient.
         */
        set_sta_flag(sta, WLAN_STA_BLOCK_BA);
        ieee80211_sta_tear_down_BA_sessions(sta, AGG_STOP_DESTROY_STA);

        /*
         * Before removing the station from the driver there might be pending
         * rx frames on RSS queues sent prior to the disassociation - wait for
         * all such frames to be processed.
         */
        drv_sync_rx_queues(local, sta);

        for (i = 0; i < ARRAY_SIZE(sta->link); i++) {
                struct link_sta_info *link_sta;

                if (!(sta->sta.valid_links & BIT(i)))
                        continue;

                link_sta = rcu_dereference_protected(sta->link[i],
                                                     lockdep_is_held(&local->sta_mtx));

                link_sta_info_hash_del(local, link_sta);
        }

        ret = sta_info_hash_del(local, sta);
        if (WARN_ON(ret))
                return ret;

        /*
         * for TDLS peers, make sure to return to the base channel before
         * removal.
         */
        if (test_sta_flag(sta, WLAN_STA_TDLS_OFF_CHANNEL)) {
                drv_tdls_cancel_channel_switch(local, sdata, &sta->sta);
                clear_sta_flag(sta, WLAN_STA_TDLS_OFF_CHANNEL);
        }

        list_del_rcu(&sta->list);
        sta->removed = true;

        drv_sta_pre_rcu_remove(local, sta->sdata, sta);

        if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN &&
            rcu_access_pointer(sdata->u.vlan.sta) == sta)
                RCU_INIT_POINTER(sdata->u.vlan.sta, NULL);

        return 0;
}

static void __sta_info_destroy_part2(struct sta_info *sta)
{
        struct ieee80211_local *local = sta->local;
        struct ieee80211_sub_if_data *sdata = sta->sdata;
        struct station_info *sinfo;
        int ret;

        /*
         * NOTE: This assumes at least synchronize_net() was done
         *       after _part1 and before _part2!
         */

        might_sleep();
        lockdep_assert_held(&local->sta_mtx);

        if (sta->sta_state == IEEE80211_STA_AUTHORIZED) {
                ret = sta_info_move_state(sta, IEEE80211_STA_ASSOC);
                WARN_ON_ONCE(ret);
        }

        /* now keys can no longer be reached */
        ieee80211_free_sta_keys(local, sta);

        /* disable TIM bit - last chance to tell driver */
        __sta_info_recalc_tim(sta, true);

        sta->dead = true;

        local->num_sta--;
        local->sta_generation++;

        while (sta->sta_state > IEEE80211_STA_NONE) {
                ret = sta_info_move_state(sta, sta->sta_state - 1);
                if (ret) {
                        WARN_ON_ONCE(1);
                        break;
                }
        }

        if (sta->uploaded) {
                ret = drv_sta_state(local, sdata, sta, IEEE80211_STA_NONE,
                                    IEEE80211_STA_NOTEXIST);
                WARN_ON_ONCE(ret != 0);
        }

        sta_dbg(sdata, "Removed STA %pM\n", sta->sta.addr);

        sinfo = kzalloc(sizeof(*sinfo), GFP_KERNEL);
        if (sinfo)
                sta_set_sinfo(sta, sinfo, true);
        cfg80211_del_sta_sinfo(sdata->dev, sta->sta.addr, sinfo, GFP_KERNEL);
        kfree(sinfo);

        ieee80211_sta_debugfs_remove(sta);

        ieee80211_destroy_frag_cache(&sta->frags);

        cleanup_single_sta(sta);
}

int __must_check __sta_info_destroy(struct sta_info *sta)
{
        int err = __sta_info_destroy_part1(sta);

        if (err)
                return err;

        synchronize_net();

        __sta_info_destroy_part2(sta);

        return 0;
}

int sta_info_destroy_addr(struct ieee80211_sub_if_data *sdata, const u8 *addr)
{
        struct sta_info *sta;
        int ret;

        mutex_lock(&sdata->local->sta_mtx);
        sta = sta_info_get(sdata, addr);
        ret = __sta_info_destroy(sta);
        mutex_unlock(&sdata->local->sta_mtx);

        return ret;
}

int sta_info_destroy_addr_bss(struct ieee80211_sub_if_data *sdata,
                              const u8 *addr)
{
        struct sta_info *sta;
        int ret;

        mutex_lock(&sdata->local->sta_mtx);
        sta = sta_info_get_bss(sdata, addr);
        ret = __sta_info_destroy(sta);
        mutex_unlock(&sdata->local->sta_mtx);

        return ret;
}

static void sta_info_cleanup(struct timer_list *t)
{
        struct ieee80211_local *local = from_timer(local, t, sta_cleanup);
        struct sta_info *sta;
        bool timer_needed = false;

        rcu_read_lock();
        list_for_each_entry_rcu(sta, &local->sta_list, list)
                if (sta_info_cleanup_expire_buffered(local, sta))
                        timer_needed = true;
        rcu_read_unlock();

        if (local->quiescing)
                return;

        if (!timer_needed)
                return;

        mod_timer(&local->sta_cleanup,
                  round_jiffies(jiffies + STA_INFO_CLEANUP_INTERVAL));
}

int sta_info_init(struct ieee80211_local *local)
{
        int err;

        err = rhltable_init(&local->sta_hash, &sta_rht_params);
        if (err)
                return err;

        err = rhltable_init(&local->link_sta_hash, &link_sta_rht_params);
        if (err) {
                rhltable_destroy(&local->sta_hash);
                return err;
        }

        spin_lock_init(&local->tim_lock);
        mutex_init(&local->sta_mtx);
        INIT_LIST_HEAD(&local->sta_list);

        timer_setup(&local->sta_cleanup, sta_info_cleanup, 0);
        return 0;
}

void sta_info_stop(struct ieee80211_local *local)
{
        del_timer_sync(&local->sta_cleanup);
        rhltable_destroy(&local->sta_hash);
        rhltable_destroy(&local->link_sta_hash);
}


int __sta_info_flush(struct ieee80211_sub_if_data *sdata, bool vlans)
{
        struct ieee80211_local *local = sdata->local;
        struct sta_info *sta, *tmp;
        LIST_HEAD(free_list);
        int ret = 0;

        might_sleep();

        WARN_ON(vlans && sdata->vif.type != NL80211_IFTYPE_AP);
        WARN_ON(vlans && !sdata->bss);

        mutex_lock(&local->sta_mtx);
        list_for_each_entry_safe(sta, tmp, &local->sta_list, list) {
                if (sdata == sta->sdata ||
                    (vlans && sdata->bss == sta->sdata->bss)) {
                        if (!WARN_ON(__sta_info_destroy_part1(sta)))
                                list_add(&sta->free_list, &free_list);
                        ret++;
                }
        }

        if (!list_empty(&free_list)) {
                synchronize_net();
                list_for_each_entry_safe(sta, tmp, &free_list, free_list)
                        __sta_info_destroy_part2(sta);
        }
        mutex_unlock(&local->sta_mtx);

        return ret;
}

void ieee80211_sta_expire(struct ieee80211_sub_if_data *sdata,
                          unsigned long exp_time)
{
        struct ieee80211_local *local = sdata->local;
        struct sta_info *sta, *tmp;

        mutex_lock(&local->sta_mtx);

        list_for_each_entry_safe(sta, tmp, &local->sta_list, list) {
                unsigned long last_active = ieee80211_sta_last_active(sta);

                if (sdata != sta->sdata)
                        continue;

                if (time_is_before_jiffies(last_active + exp_time)) {
                        sta_dbg(sta->sdata, "expiring inactive STA %pM\n",
                                sta->sta.addr);

                        if (ieee80211_vif_is_mesh(&sdata->vif) &&
                            test_sta_flag(sta, WLAN_STA_PS_STA))
                                atomic_dec(&sdata->u.mesh.ps.num_sta_ps);

                        WARN_ON(__sta_info_destroy(sta));
                }
        }

        mutex_unlock(&local->sta_mtx);
}

struct ieee80211_sta *ieee80211_find_sta_by_ifaddr(struct ieee80211_hw *hw,
                                                   const u8 *addr,
                                                   const u8 *localaddr)
{
        struct ieee80211_local *local = hw_to_local(hw);
        struct rhlist_head *tmp;
        struct sta_info *sta;

        /*
         * Just return a random station if localaddr is NULL
         * ... first in list.
         */
        for_each_sta_info(local, addr, sta, tmp) {
                if (localaddr &&
                    !ether_addr_equal(sta->sdata->vif.addr, localaddr))
                        continue;
                if (!sta->uploaded)
                        return NULL;
                return &sta->sta;
        }

        return NULL;
}
EXPORT_SYMBOL_GPL(ieee80211_find_sta_by_ifaddr);

struct ieee80211_sta *ieee80211_find_sta(struct ieee80211_vif *vif,
                                         const u8 *addr)
{
        struct sta_info *sta;

        if (!vif)
                return NULL;

        sta = sta_info_get_bss(vif_to_sdata(vif), addr);
        if (!sta)
                return NULL;

        if (!sta->uploaded)
                return NULL;

        return &sta->sta;
}
EXPORT_SYMBOL(ieee80211_find_sta);

/* powersave support code */
void ieee80211_sta_ps_deliver_wakeup(struct sta_info *sta)
{
        struct ieee80211_sub_if_data *sdata = sta->sdata;
        struct ieee80211_local *local = sdata->local;
        struct sk_buff_head pending;
        int filtered = 0, buffered = 0, ac, i;
        unsigned long flags;
        struct ps_data *ps;

        if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
                sdata = container_of(sdata->bss, struct ieee80211_sub_if_data,
                                     u.ap);

        if (sdata->vif.type == NL80211_IFTYPE_AP)
                ps = &sdata->bss->ps;
        else if (ieee80211_vif_is_mesh(&sdata->vif))
                ps = &sdata->u.mesh.ps;
        else
                return;

        clear_sta_flag(sta, WLAN_STA_SP);

        BUILD_BUG_ON(BITS_TO_LONGS(IEEE80211_NUM_TIDS) > 1);
        sta->driver_buffered_tids = 0;
        sta->txq_buffered_tids = 0;

        if (!ieee80211_hw_check(&local->hw, AP_LINK_PS))
                drv_sta_notify(local, sdata, STA_NOTIFY_AWAKE, &sta->sta);

        for (i = 0; i < ARRAY_SIZE(sta->sta.txq); i++) {
                if (!sta->sta.txq[i] || !txq_has_queue(sta->sta.txq[i]))
                        continue;

                schedule_and_wake_txq(local, to_txq_info(sta->sta.txq[i]));
        }

        skb_queue_head_init(&pending);

        /* sync with ieee80211_tx_h_unicast_ps_buf */
        spin_lock(&sta->ps_lock);
        /* Send all buffered frames to the station */
        for (ac = 0; ac < IEEE80211_NUM_ACS; ac++) {
                int count = skb_queue_len(&pending), tmp;

                spin_lock_irqsave(&sta->tx_filtered[ac].lock, flags);
                skb_queue_splice_tail_init(&sta->tx_filtered[ac], &pending);
                spin_unlock_irqrestore(&sta->tx_filtered[ac].lock, flags);
                tmp = skb_queue_len(&pending);
                filtered += tmp - count;
                count = tmp;

                spin_lock_irqsave(&sta->ps_tx_buf[ac].lock, flags);
                skb_queue_splice_tail_init(&sta->ps_tx_buf[ac], &pending);
                spin_unlock_irqrestore(&sta->ps_tx_buf[ac].lock, flags);
                tmp = skb_queue_len(&pending);
                buffered += tmp - count;
        }

        ieee80211_add_pending_skbs(local, &pending);

        /* now we're no longer in the deliver code */
        clear_sta_flag(sta, WLAN_STA_PS_DELIVER);

        /* The station might have polled and then woken up before we responded,
         * so clear these flags now to avoid them sticking around.
         */
        clear_sta_flag(sta, WLAN_STA_PSPOLL);
        clear_sta_flag(sta, WLAN_STA_UAPSD);
        spin_unlock(&sta->ps_lock);

        atomic_dec(&ps->num_sta_ps);

        local->total_ps_buffered -= buffered;

        sta_info_recalc_tim(sta);

        ps_dbg(sdata,
               "STA %pM aid %d sending %d filtered/%d PS frames since STA woke up\n",
               sta->sta.addr, sta->sta.aid, filtered, buffered);

        ieee80211_check_fast_xmit(sta);
}

static void ieee80211_send_null_response(struct sta_info *sta, int tid,
                                         enum ieee80211_frame_release_type reason,
                                         bool call_driver, bool more_data)
{
        struct ieee80211_sub_if_data *sdata = sta->sdata;
        struct ieee80211_local *local = sdata->local;
        struct ieee80211_qos_hdr *nullfunc;
        struct sk_buff *skb;
        int size = sizeof(*nullfunc);
        __le16 fc;
        bool qos = sta->sta.wme;
        struct ieee80211_tx_info *info;
        struct ieee80211_chanctx_conf *chanctx_conf;

        if (qos) {
                fc = cpu_to_le16(IEEE80211_FTYPE_DATA |
                                 IEEE80211_STYPE_QOS_NULLFUNC |
                                 IEEE80211_FCTL_FROMDS);
        } else {
                size -= 2;
                fc = cpu_to_le16(IEEE80211_FTYPE_DATA |
                                 IEEE80211_STYPE_NULLFUNC |
                                 IEEE80211_FCTL_FROMDS);
        }

        skb = dev_alloc_skb(local->hw.extra_tx_headroom + size);
        if (!skb)
                return;

        skb_reserve(skb, local->hw.extra_tx_headroom);

        nullfunc = skb_put(skb, size);
        nullfunc->frame_control = fc;
        nullfunc->duration_id = 0;
        memcpy(nullfunc->addr1, sta->sta.addr, ETH_ALEN);
        memcpy(nullfunc->addr2, sdata->vif.addr, ETH_ALEN);
        memcpy(nullfunc->addr3, sdata->vif.addr, ETH_ALEN);
        nullfunc->seq_ctrl = 0;

        skb->priority = tid;
        skb_set_queue_mapping(skb, ieee802_1d_to_ac[tid]);
        if (qos) {
                nullfunc->qos_ctrl = cpu_to_le16(tid);

                if (reason == IEEE80211_FRAME_RELEASE_UAPSD) {
                        nullfunc->qos_ctrl |=
                                cpu_to_le16(IEEE80211_QOS_CTL_EOSP);
                        if (more_data)
                                nullfunc->frame_control |=
                                        cpu_to_le16(IEEE80211_FCTL_MOREDATA);
                }
        }

        info = IEEE80211_SKB_CB(skb);

        /*
         * Tell TX path to send this frame even though the
         * STA may still remain is PS mode after this frame
         * exchange. Also set EOSP to indicate this packet
         * ends the poll/service period.
         */
        info->flags |= IEEE80211_TX_CTL_NO_PS_BUFFER |
                       IEEE80211_TX_STATUS_EOSP |
                       IEEE80211_TX_CTL_REQ_TX_STATUS;

        info->control.flags |= IEEE80211_TX_CTRL_PS_RESPONSE;

        if (call_driver)
                drv_allow_buffered_frames(local, sta, BIT(tid), 1,
                                          reason, false);

        skb->dev = sdata->dev;

        rcu_read_lock();
        chanctx_conf = rcu_dereference(sdata->vif.bss_conf.chanctx_conf);
        if (WARN_ON(!chanctx_conf)) {
                rcu_read_unlock();
                kfree_skb(skb);
                return;
        }

        info->band = chanctx_conf->def.chan->band;
        ieee80211_xmit(sdata, sta, skb);
        rcu_read_unlock();
}

static int find_highest_prio_tid(unsigned long tids)
{
        /* lower 3 TIDs aren't ordered perfectly */
        if (tids & 0xF8)
                return fls(tids) - 1;
        /* TID 0 is BE just like TID 3 */
        if (tids & BIT(0))
                return 0;
        return fls(tids) - 1;
}

/* Indicates if the MORE_DATA bit should be set in the last
 * frame obtained by ieee80211_sta_ps_get_frames.
 * Note that driver_release_tids is relevant only if
 * reason = IEEE80211_FRAME_RELEASE_PSPOLL
 */
static bool
ieee80211_sta_ps_more_data(struct sta_info *sta, u8 ignored_acs,
                           enum ieee80211_frame_release_type reason,
                           unsigned long driver_release_tids)
{
        int ac;

        /* If the driver has data on more than one TID then
         * certainly there's more data if we release just a
         * single frame now (from a single TID). This will
         * only happen for PS-Poll.
         */
        if (reason == IEEE80211_FRAME_RELEASE_PSPOLL &&
            hweight16(driver_release_tids) > 1)
                return true;

        for (ac = 0; ac < IEEE80211_NUM_ACS; ac++) {
                if (ignored_acs & ieee80211_ac_to_qos_mask[ac])
                        continue;

                if (!skb_queue_empty(&sta->tx_filtered[ac]) ||
                    !skb_queue_empty(&sta->ps_tx_buf[ac]))
                        return true;
        }

        return false;
}

static void
ieee80211_sta_ps_get_frames(struct sta_info *sta, int n_frames, u8 ignored_acs,
                            enum ieee80211_frame_release_type reason,
                            struct sk_buff_head *frames,
                            unsigned long *driver_release_tids)
{
        struct ieee80211_sub_if_data *sdata = sta->sdata;
        struct ieee80211_local *local = sdata->local;
        int ac;

        /* Get response frame(s) and more data bit for the last one. */
        for (ac = 0; ac < IEEE80211_NUM_ACS; ac++) {
                unsigned long tids;

                if (ignored_acs & ieee80211_ac_to_qos_mask[ac])
                        continue;

                tids = ieee80211_tids_for_ac(ac);

                /* if we already have frames from software, then we can't also
                 * release from hardware queues
                 */
                if (skb_queue_empty(frames)) {
                        *driver_release_tids |=
                                sta->driver_buffered_tids & tids;
                        *driver_release_tids |= sta->txq_buffered_tids & tids;
                }

                if (!*driver_release_tids) {
                        struct sk_buff *skb;

                        while (n_frames > 0) {
                                skb = skb_dequeue(&sta->tx_filtered[ac]);
                                if (!skb) {
                                        skb = skb_dequeue(
                                                &sta->ps_tx_buf[ac]);
                                        if (skb)
                                                local->total_ps_buffered--;
                                }
                                if (!skb)
                                        break;
                                n_frames--;
                                __skb_queue_tail(frames, skb);
                        }
                }

                /* If we have more frames buffered on this AC, then abort the
                 * loop since we can't send more data from other ACs before
                 * the buffered frames from this.
                 */
                if (!skb_queue_empty(&sta->tx_filtered[ac]) ||
                    !skb_queue_empty(&sta->ps_tx_buf[ac]))
                        break;
        }
}

static void
ieee80211_sta_ps_deliver_response(struct sta_info *sta,
                                  int n_frames, u8 ignored_acs,
                                  enum ieee80211_frame_release_type reason)
{
        struct ieee80211_sub_if_data *sdata = sta->sdata;
        struct ieee80211_local *local = sdata->local;
        unsigned long driver_release_tids = 0;
        struct sk_buff_head frames;
        bool more_data;

        /* Service or PS-Poll period starts */
        set_sta_flag(sta, WLAN_STA_SP);

        __skb_queue_head_init(&frames);

        ieee80211_sta_ps_get_frames(sta, n_frames, ignored_acs, reason,
                                    &frames, &driver_release_tids);

        more_data = ieee80211_sta_ps_more_data(sta, ignored_acs, reason, driver_release_tids);

        if (driver_release_tids && reason == IEEE80211_FRAME_RELEASE_PSPOLL)
                driver_release_tids =
                        BIT(find_highest_prio_tid(driver_release_tids));

        if (skb_queue_empty(&frames) && !driver_release_tids) {
                int tid, ac;

                /*
                 * For PS-Poll, this can only happen due to a race condition
                 * when we set the TIM bit and the station notices it, but
                 * before it can poll for the frame we expire it.
                 *
                 * For uAPSD, this is said in the standard (11.2.1.5 h):
                 *      At each unscheduled SP for a non-AP STA, the AP shall
                 *      attempt to transmit at least one MSDU or MMPDU, but no
                 *      more than the value specified in the Max SP Length field
                 *      in the QoS Capability element from delivery-enabled ACs,
                 *      that are destined for the non-AP STA.
                 *
                 * Since we have no other MSDU/MMPDU, transmit a QoS null frame.
                 */

                /* This will evaluate to 1, 3, 5 or 7. */
                for (ac = IEEE80211_AC_VO; ac < IEEE80211_NUM_ACS; ac++)
                        if (!(ignored_acs & ieee80211_ac_to_qos_mask[ac]))
                                break;
                tid = 7 - 2 * ac;

                ieee80211_send_null_response(sta, tid, reason, true, false);
        } else if (!driver_release_tids) {
                struct sk_buff_head pending;
                struct sk_buff *skb;
                int num = 0;
                u16 tids = 0;
                bool need_null = false;

                skb_queue_head_init(&pending);

                while ((skb = __skb_dequeue(&frames))) {
                        struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
                        struct ieee80211_hdr *hdr = (void *) skb->data;
                        u8 *qoshdr = NULL;

                        num++;

                        /*
                         * Tell TX path to send this frame even though the
                         * STA may still remain is PS mode after this frame
                         * exchange.
                         */
                        info->flags |= IEEE80211_TX_CTL_NO_PS_BUFFER;
                        info->control.flags |= IEEE80211_TX_CTRL_PS_RESPONSE;

                        /*
                         * Use MoreData flag to indicate whether there are
                         * more buffered frames for this STA
                         */
                        if (more_data || !skb_queue_empty(&frames))
                                hdr->frame_control |=
                                        cpu_to_le16(IEEE80211_FCTL_MOREDATA);
                        else
                                hdr->frame_control &=
                                        cpu_to_le16(~IEEE80211_FCTL_MOREDATA);

                        if (ieee80211_is_data_qos(hdr->frame_control) ||
                            ieee80211_is_qos_nullfunc(hdr->frame_control))
                                qoshdr = ieee80211_get_qos_ctl(hdr);

                        tids |= BIT(skb->priority);

                        __skb_queue_tail(&pending, skb);

                        /* end service period after last frame or add one */
                        if (!skb_queue_empty(&frames))
                                continue;

                        if (reason != IEEE80211_FRAME_RELEASE_UAPSD) {
                                /* for PS-Poll, there's only one frame */
                                info->flags |= IEEE80211_TX_STATUS_EOSP |
                                               IEEE80211_TX_CTL_REQ_TX_STATUS;
                                break;
                        }

                        /* For uAPSD, things are a bit more complicated. If the
                         * last frame has a QoS header (i.e. is a QoS-data or
                         * QoS-nulldata frame) then just set the EOSP bit there
                         * and be done.
                         * If the frame doesn't have a QoS header (which means
                         * it should be a bufferable MMPDU) then we can't set
                         * the EOSP bit in the QoS header; add a QoS-nulldata
                         * frame to the list to send it after the MMPDU.
                         *
                         * Note that this code is only in the mac80211-release
                         * code path, we assume that the driver will not buffer
                         * anything but QoS-data frames, or if it does, will
                         * create the QoS-nulldata frame by itself if needed.
                         *
                         * Cf. 802.11-2012 10.2.1.10 (c).
                         */
                        if (qoshdr) {
                                *qoshdr |= IEEE80211_QOS_CTL_EOSP;

                                info->flags |= IEEE80211_TX_STATUS_EOSP |
                                               IEEE80211_TX_CTL_REQ_TX_STATUS;
                        } else {
                                /* The standard isn't completely clear on this
                                 * as it says the more-data bit should be set
                                 * if there are more BUs. The QoS-Null frame
                                 * we're about to send isn't buffered yet, we
                                 * only create it below, but let's pretend it
                                 * was buffered just in case some clients only
                                 * expect more-data=0 when eosp=1.
                                 */
                                hdr->frame_control |=
                                        cpu_to_le16(IEEE80211_FCTL_MOREDATA);
                                need_null = true;
                                num++;
                        }
                        break;
                }

                drv_allow_buffered_frames(local, sta, tids, num,
                                          reason, more_data);

                ieee80211_add_pending_skbs(local, &pending);

                if (need_null)
                        ieee80211_send_null_response(
                                sta, find_highest_prio_tid(tids),
                                reason, false, false);

                sta_info_recalc_tim(sta);
        } else {
                int tid;

                /*
                 * We need to release a frame that is buffered somewhere in the
                 * driver ... it'll have to handle that.
                 * Note that the driver also has to check the number of frames
                 * on the TIDs we're releasing from - if there are more than
                 * n_frames it has to set the more-data bit (if we didn't ask
                 * it to set it anyway due to other buffered frames); if there
                 * are fewer than n_frames it has to make sure to adjust that
                 * to allow the service period to end properly.
                 */
                drv_release_buffered_frames(local, sta, driver_release_tids,
                                            n_frames, reason, more_data);

                /*
                 * Note that we don't recalculate the TIM bit here as it would
                 * most likely have no effect at all unless the driver told us
                 * that the TID(s) became empty before returning here from the
                 * release function.
                 * Either way, however, when the driver tells us that the TID(s)
                 * became empty or we find that a txq became empty, we'll do the
                 * TIM recalculation.
                 */

                if (!sta->sta.txq[0])
                        return;

                for (tid = 0; tid < ARRAY_SIZE(sta->sta.txq); tid++) {
                        if (!sta->sta.txq[tid] ||
                            !(driver_release_tids & BIT(tid)) ||
                            txq_has_queue(sta->sta.txq[tid]))
                                continue;

                        sta_info_recalc_tim(sta);
                        break;
                }
        }
}

void ieee80211_sta_ps_deliver_poll_response(struct sta_info *sta)
{
        u8 ignore_for_response = sta->sta.uapsd_queues;

        /*
         * If all ACs are delivery-enabled then we should reply
         * from any of them, if only some are enabled we reply
         * only from the non-enabled ones.
         */
        if (ignore_for_response == BIT(IEEE80211_NUM_ACS) - 1)
                ignore_for_response = 0;

        ieee80211_sta_ps_deliver_response(sta, 1, ignore_for_response,
                                          IEEE80211_FRAME_RELEASE_PSPOLL);
}

void ieee80211_sta_ps_deliver_uapsd(struct sta_info *sta)
{
        int n_frames = sta->sta.max_sp;
        u8 delivery_enabled = sta->sta.uapsd_queues;

        /*
         * If we ever grow support for TSPEC this might happen if
         * the TSPEC update from hostapd comes in between a trigger
         * frame setting WLAN_STA_UAPSD in the RX path and this
         * actually getting called.
         */
        if (!delivery_enabled)
                return;

        switch (sta->sta.max_sp) {
        case 1:
                n_frames = 2;
                break;
        case 2:
                n_frames = 4;
                break;
        case 3:
                n_frames = 6;
                break;
        case 0:
                /* XXX: what is a good value? */
                n_frames = 128;
                break;
        }

        ieee80211_sta_ps_deliver_response(sta, n_frames, ~delivery_enabled,
                                          IEEE80211_FRAME_RELEASE_UAPSD);
}

void ieee80211_sta_block_awake(struct ieee80211_hw *hw,
                               struct ieee80211_sta *pubsta, bool block)
{
        struct sta_info *sta = container_of(pubsta, struct sta_info, sta);

        trace_api_sta_block_awake(sta->local, pubsta, block);

        if (block) {
                set_sta_flag(sta, WLAN_STA_PS_DRIVER);
                ieee80211_clear_fast_xmit(sta);
                return;
        }

        if (!test_sta_flag(sta, WLAN_STA_PS_DRIVER))
                return;

        if (!test_sta_flag(sta, WLAN_STA_PS_STA)) {
                set_sta_flag(sta, WLAN_STA_PS_DELIVER);
                clear_sta_flag(sta, WLAN_STA_PS_DRIVER);
                ieee80211_queue_work(hw, &sta->drv_deliver_wk);
        } else if (test_sta_flag(sta, WLAN_STA_PSPOLL) ||
                   test_sta_flag(sta, WLAN_STA_UAPSD)) {
                /* must be asleep in this case */
                clear_sta_flag(sta, WLAN_STA_PS_DRIVER);
                ieee80211_queue_work(hw, &sta->drv_deliver_wk);
        } else {
                clear_sta_flag(sta, WLAN_STA_PS_DRIVER);
                ieee80211_check_fast_xmit(sta);
        }
}
EXPORT_SYMBOL(ieee80211_sta_block_awake);

void ieee80211_sta_eosp(struct ieee80211_sta *pubsta)
{
        struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
        struct ieee80211_local *local = sta->local;

        trace_api_eosp(local, pubsta);

        clear_sta_flag(sta, WLAN_STA_SP);
}
EXPORT_SYMBOL(ieee80211_sta_eosp);

void ieee80211_send_eosp_nullfunc(struct ieee80211_sta *pubsta, int tid)
{
        struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
        enum ieee80211_frame_release_type reason;
        bool more_data;

        trace_api_send_eosp_nullfunc(sta->local, pubsta, tid);

        reason = IEEE80211_FRAME_RELEASE_UAPSD;
        more_data = ieee80211_sta_ps_more_data(sta, ~sta->sta.uapsd_queues,
                                               reason, 0);

        ieee80211_send_null_response(sta, tid, reason, false, more_data);
}
EXPORT_SYMBOL(ieee80211_send_eosp_nullfunc);

void ieee80211_sta_set_buffered(struct ieee80211_sta *pubsta,
                                u8 tid, bool buffered)
{
        struct sta_info *sta = container_of(pubsta, struct sta_info, sta);

        if (WARN_ON(tid >= IEEE80211_NUM_TIDS))
                return;

        trace_api_sta_set_buffered(sta->local, pubsta, tid, buffered);

        if (buffered)
                set_bit(tid, &sta->driver_buffered_tids);
        else
                clear_bit(tid, &sta->driver_buffered_tids);

        sta_info_recalc_tim(sta);
}
EXPORT_SYMBOL(ieee80211_sta_set_buffered);

void ieee80211_sta_register_airtime(struct ieee80211_sta *pubsta, u8 tid,
                                    u32 tx_airtime, u32 rx_airtime)
{
        struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
        struct ieee80211_local *local = sta->sdata->local;
        u8 ac = ieee80211_ac_from_tid(tid);
        u32 airtime = 0;
        u32 diff;

        if (sta->local->airtime_flags & AIRTIME_USE_TX)
                airtime += tx_airtime;
        if (sta->local->airtime_flags & AIRTIME_USE_RX)
                airtime += rx_airtime;

        spin_lock_bh(&local->active_txq_lock[ac]);
        sta->airtime[ac].tx_airtime += tx_airtime;
        sta->airtime[ac].rx_airtime += rx_airtime;

        diff = (u32)jiffies - sta->airtime[ac].last_active;
        if (diff <= AIRTIME_ACTIVE_DURATION)
                sta->airtime[ac].deficit -= airtime;

        spin_unlock_bh(&local->active_txq_lock[ac]);
}
EXPORT_SYMBOL(ieee80211_sta_register_airtime);

void ieee80211_sta_update_pending_airtime(struct ieee80211_local *local,
                                          struct sta_info *sta, u8 ac,
                                          u16 tx_airtime, bool tx_completed)
{
        int tx_pending;

        if (!wiphy_ext_feature_isset(local->hw.wiphy, NL80211_EXT_FEATURE_AQL))
                return;

        if (!tx_completed) {
                if (sta)
                        atomic_add(tx_airtime,
                                   &sta->airtime[ac].aql_tx_pending);

                atomic_add(tx_airtime, &local->aql_total_pending_airtime);
                atomic_add(tx_airtime, &local->aql_ac_pending_airtime[ac]);
                return;
        }

        if (sta) {
                tx_pending = atomic_sub_return(tx_airtime,
                                               &sta->airtime[ac].aql_tx_pending);
                if (tx_pending < 0)
                        atomic_cmpxchg(&sta->airtime[ac].aql_tx_pending,
                                       tx_pending, 0);
        }

        atomic_sub(tx_airtime, &local->aql_total_pending_airtime);
        tx_pending = atomic_sub_return(tx_airtime,
                                       &local->aql_ac_pending_airtime[ac]);
        if (WARN_ONCE(tx_pending < 0,
                      "Device %s AC %d pending airtime underflow: %u, %u",
                      wiphy_name(local->hw.wiphy), ac, tx_pending,
                      tx_airtime)) {
                atomic_cmpxchg(&local->aql_ac_pending_airtime[ac],
                               tx_pending, 0);
                atomic_sub(tx_pending, &local->aql_total_pending_airtime);
        }
}

int sta_info_move_state(struct sta_info *sta,
                        enum ieee80211_sta_state new_state)
{
        might_sleep();

        if (sta->sta_state == new_state)
                return 0;

        /* check allowed transitions first */

        switch (new_state) {
        case IEEE80211_STA_NONE:
                if (sta->sta_state != IEEE80211_STA_AUTH)
                        return -EINVAL;
                break;
        case IEEE80211_STA_AUTH:
                if (sta->sta_state != IEEE80211_STA_NONE &&
                    sta->sta_state != IEEE80211_STA_ASSOC)
                        return -EINVAL;
                break;
        case IEEE80211_STA_ASSOC:
                if (sta->sta_state != IEEE80211_STA_AUTH &&
                    sta->sta_state != IEEE80211_STA_AUTHORIZED)
                        return -EINVAL;
                break;
        case IEEE80211_STA_AUTHORIZED:
                if (sta->sta_state != IEEE80211_STA_ASSOC)
                        return -EINVAL;
                break;
        default:
                WARN(1, "invalid state %d", new_state);
                return -EINVAL;
        }

        sta_dbg(sta->sdata, "moving STA %pM to state %d\n",
                sta->sta.addr, new_state);

        /*
         * notify the driver before the actual changes so it can
         * fail the transition
         */
        if (test_sta_flag(sta, WLAN_STA_INSERTED)) {
                int err = drv_sta_state(sta->local, sta->sdata, sta,
                                        sta->sta_state, new_state);
                if (err)
                        return err;
        }

        /* reflect the change in all state variables */

        switch (new_state) {
        case IEEE80211_STA_NONE:
                if (sta->sta_state == IEEE80211_STA_AUTH)
                        clear_bit(WLAN_STA_AUTH, &sta->_flags);
                break;
        case IEEE80211_STA_AUTH:
                if (sta->sta_state == IEEE80211_STA_NONE) {
                        set_bit(WLAN_STA_AUTH, &sta->_flags);
                } else if (sta->sta_state == IEEE80211_STA_ASSOC) {
                        clear_bit(WLAN_STA_ASSOC, &sta->_flags);
                        ieee80211_recalc_min_chandef(sta->sdata, -1);
                        if (!sta->sta.support_p2p_ps)
                                ieee80211_recalc_p2p_go_ps_allowed(sta->sdata);
                }
                break;
        case IEEE80211_STA_ASSOC:
                if (sta->sta_state == IEEE80211_STA_AUTH) {
                        set_bit(WLAN_STA_ASSOC, &sta->_flags);
                        sta->assoc_at = ktime_get_boottime_ns();
                        ieee80211_recalc_min_chandef(sta->sdata, -1);
                        if (!sta->sta.support_p2p_ps)
                                ieee80211_recalc_p2p_go_ps_allowed(sta->sdata);
                } else if (sta->sta_state == IEEE80211_STA_AUTHORIZED) {
                        ieee80211_vif_dec_num_mcast(sta->sdata);
                        clear_bit(WLAN_STA_AUTHORIZED, &sta->_flags);
                        ieee80211_clear_fast_xmit(sta);
                        ieee80211_clear_fast_rx(sta);
                }
                break;
        case IEEE80211_STA_AUTHORIZED:
                if (sta->sta_state == IEEE80211_STA_ASSOC) {
                        ieee80211_vif_inc_num_mcast(sta->sdata);
                        set_bit(WLAN_STA_AUTHORIZED, &sta->_flags);
                        ieee80211_check_fast_xmit(sta);
                        ieee80211_check_fast_rx(sta);
                }
                if (sta->sdata->vif.type == NL80211_IFTYPE_AP_VLAN ||
                    sta->sdata->vif.type == NL80211_IFTYPE_AP)
                        cfg80211_send_layer2_update(sta->sdata->dev,
                                                    sta->sta.addr);
                break;
        default:
                break;
        }

        sta->sta_state = new_state;

        return 0;
}

static struct ieee80211_sta_rx_stats *
sta_get_last_rx_stats(struct sta_info *sta)
{
        struct ieee80211_sta_rx_stats *stats = &sta->deflink.rx_stats;
        int cpu;

        if (!sta->deflink.pcpu_rx_stats)
                return stats;

        for_each_possible_cpu(cpu) {
                struct ieee80211_sta_rx_stats *cpustats;

                cpustats = per_cpu_ptr(sta->deflink.pcpu_rx_stats, cpu);

                if (time_after(cpustats->last_rx, stats->last_rx))
                        stats = cpustats;
        }

        return stats;
}

static void sta_stats_decode_rate(struct ieee80211_local *local, u32 rate,
                                  struct rate_info *rinfo)
{
        rinfo->bw = STA_STATS_GET(BW, rate);

        switch (STA_STATS_GET(TYPE, rate)) {
        case STA_STATS_RATE_TYPE_VHT:
                rinfo->flags = RATE_INFO_FLAGS_VHT_MCS;
                rinfo->mcs = STA_STATS_GET(VHT_MCS, rate);
                rinfo->nss = STA_STATS_GET(VHT_NSS, rate);
                if (STA_STATS_GET(SGI, rate))
                        rinfo->flags |= RATE_INFO_FLAGS_SHORT_GI;
                break;
        case STA_STATS_RATE_TYPE_HT:
                rinfo->flags = RATE_INFO_FLAGS_MCS;
                rinfo->mcs = STA_STATS_GET(HT_MCS, rate);
                if (STA_STATS_GET(SGI, rate))
                        rinfo->flags |= RATE_INFO_FLAGS_SHORT_GI;
                break;
        case STA_STATS_RATE_TYPE_LEGACY: {
                struct ieee80211_supported_band *sband;
                u16 brate;
                unsigned int shift;
                int band = STA_STATS_GET(LEGACY_BAND, rate);
                int rate_idx = STA_STATS_GET(LEGACY_IDX, rate);

                sband = local->hw.wiphy->bands[band];

                if (WARN_ON_ONCE(!sband->bitrates))
                        break;

                brate = sband->bitrates[rate_idx].bitrate;
                if (rinfo->bw == RATE_INFO_BW_5)
                        shift = 2;
                else if (rinfo->bw == RATE_INFO_BW_10)
                        shift = 1;
                else
                        shift = 0;
                rinfo->legacy = DIV_ROUND_UP(brate, 1 << shift);
                break;
                }
        case STA_STATS_RATE_TYPE_HE:
                rinfo->flags = RATE_INFO_FLAGS_HE_MCS;
                rinfo->mcs = STA_STATS_GET(HE_MCS, rate);
                rinfo->nss = STA_STATS_GET(HE_NSS, rate);
                rinfo->he_gi = STA_STATS_GET(HE_GI, rate);
                rinfo->he_ru_alloc = STA_STATS_GET(HE_RU, rate);
                rinfo->he_dcm = STA_STATS_GET(HE_DCM, rate);
                break;
        }
}

static int sta_set_rate_info_rx(struct sta_info *sta, struct rate_info *rinfo)
{
        u16 rate = READ_ONCE(sta_get_last_rx_stats(sta)->last_rate);

        if (rate == STA_STATS_RATE_INVALID)
                return -EINVAL;

        sta_stats_decode_rate(sta->local, rate, rinfo);
        return 0;
}

static inline u64 sta_get_tidstats_msdu(struct ieee80211_sta_rx_stats *rxstats,
                                        int tid)
{
        unsigned int start;
        u64 value;

        do {
                start = u64_stats_fetch_begin(&rxstats->syncp);
                value = rxstats->msdu[tid];
        } while (u64_stats_fetch_retry(&rxstats->syncp, start));

        return value;
}

static void sta_set_tidstats(struct sta_info *sta,
                             struct cfg80211_tid_stats *tidstats,
                             int tid)
{
        struct ieee80211_local *local = sta->local;
        int cpu;

        if (!(tidstats->filled & BIT(NL80211_TID_STATS_RX_MSDU))) {
                tidstats->rx_msdu += sta_get_tidstats_msdu(&sta->deflink.rx_stats,
                                                           tid);

                if (sta->deflink.pcpu_rx_stats) {
                        for_each_possible_cpu(cpu) {
                                struct ieee80211_sta_rx_stats *cpurxs;

                                cpurxs = per_cpu_ptr(sta->deflink.pcpu_rx_stats,
                                                     cpu);
                                tidstats->rx_msdu +=
                                        sta_get_tidstats_msdu(cpurxs, tid);
                        }
                }

                tidstats->filled |= BIT(NL80211_TID_STATS_RX_MSDU);
        }

        if (!(tidstats->filled & BIT(NL80211_TID_STATS_TX_MSDU))) {
                tidstats->filled |= BIT(NL80211_TID_STATS_TX_MSDU);
                tidstats->tx_msdu = sta->deflink.tx_stats.msdu[tid];
        }

        if (!(tidstats->filled & BIT(NL80211_TID_STATS_TX_MSDU_RETRIES)) &&
            ieee80211_hw_check(&local->hw, REPORTS_TX_ACK_STATUS)) {
                tidstats->filled |= BIT(NL80211_TID_STATS_TX_MSDU_RETRIES);
                tidstats->tx_msdu_retries = sta->deflink.status_stats.msdu_retries[tid];
        }

        if (!(tidstats->filled & BIT(NL80211_TID_STATS_TX_MSDU_FAILED)) &&
            ieee80211_hw_check(&local->hw, REPORTS_TX_ACK_STATUS)) {
                tidstats->filled |= BIT(NL80211_TID_STATS_TX_MSDU_FAILED);
                tidstats->tx_msdu_failed = sta->deflink.status_stats.msdu_failed[tid];
        }

        if (local->ops->wake_tx_queue && tid < IEEE80211_NUM_TIDS) {
                spin_lock_bh(&local->fq.lock);
                rcu_read_lock();

                tidstats->filled |= BIT(NL80211_TID_STATS_TXQ_STATS);
                ieee80211_fill_txq_stats(&tidstats->txq_stats,
                                         to_txq_info(sta->sta.txq[tid]));

                rcu_read_unlock();
                spin_unlock_bh(&local->fq.lock);
        }
}

static inline u64 sta_get_stats_bytes(struct ieee80211_sta_rx_stats *rxstats)
{
        unsigned int start;
        u64 value;

        do {
                start = u64_stats_fetch_begin(&rxstats->syncp);
                value = rxstats->bytes;
        } while (u64_stats_fetch_retry(&rxstats->syncp, start));

        return value;
}

void sta_set_sinfo(struct sta_info *sta, struct station_info *sinfo,
                   bool tidstats)
{
        struct ieee80211_sub_if_data *sdata = sta->sdata;
        struct ieee80211_local *local = sdata->local;
        u32 thr = 0;
        int i, ac, cpu;
        struct ieee80211_sta_rx_stats *last_rxstats;

        last_rxstats = sta_get_last_rx_stats(sta);

        sinfo->generation = sdata->local->sta_generation;

        /* do before driver, so beacon filtering drivers have a
         * chance to e.g. just add the number of filtered beacons
         * (or just modify the value entirely, of course)
         */
        if (sdata->vif.type == NL80211_IFTYPE_STATION)
                sinfo->rx_beacon = sdata->deflink.u.mgd.count_beacon_signal;

        drv_sta_statistics(local, sdata, &sta->sta, sinfo);
        sinfo->filled |= BIT_ULL(NL80211_STA_INFO_INACTIVE_TIME) |
                         BIT_ULL(NL80211_STA_INFO_STA_FLAGS) |
                         BIT_ULL(NL80211_STA_INFO_BSS_PARAM) |
                         BIT_ULL(NL80211_STA_INFO_CONNECTED_TIME) |
                         BIT_ULL(NL80211_STA_INFO_ASSOC_AT_BOOTTIME) |
                         BIT_ULL(NL80211_STA_INFO_RX_DROP_MISC);

        if (sdata->vif.type == NL80211_IFTYPE_STATION) {
                sinfo->beacon_loss_count =
                        sdata->deflink.u.mgd.beacon_loss_count;
                sinfo->filled |= BIT_ULL(NL80211_STA_INFO_BEACON_LOSS);
        }

        sinfo->connected_time = ktime_get_seconds() - sta->last_connected;
        sinfo->assoc_at = sta->assoc_at;
        sinfo->inactive_time =
                jiffies_to_msecs(jiffies - ieee80211_sta_last_active(sta));

        if (!(sinfo->filled & (BIT_ULL(NL80211_STA_INFO_TX_BYTES64) |
                               BIT_ULL(NL80211_STA_INFO_TX_BYTES)))) {
                sinfo->tx_bytes = 0;
                for (ac = 0; ac < IEEE80211_NUM_ACS; ac++)
                        sinfo->tx_bytes += sta->deflink.tx_stats.bytes[ac];
                sinfo->filled |= BIT_ULL(NL80211_STA_INFO_TX_BYTES64);
        }

        if (!(sinfo->filled & BIT_ULL(NL80211_STA_INFO_TX_PACKETS))) {
                sinfo->tx_packets = 0;
                for (ac = 0; ac < IEEE80211_NUM_ACS; ac++)
                        sinfo->tx_packets += sta->deflink.tx_stats.packets[ac];
                sinfo->filled |= BIT_ULL(NL80211_STA_INFO_TX_PACKETS);
        }

        if (!(sinfo->filled & (BIT_ULL(NL80211_STA_INFO_RX_BYTES64) |
                               BIT_ULL(NL80211_STA_INFO_RX_BYTES)))) {
                sinfo->rx_bytes += sta_get_stats_bytes(&sta->deflink.rx_stats);

                if (sta->deflink.pcpu_rx_stats) {
                        for_each_possible_cpu(cpu) {
                                struct ieee80211_sta_rx_stats *cpurxs;

                                cpurxs = per_cpu_ptr(sta->deflink.pcpu_rx_stats,
                                                     cpu);
                                sinfo->rx_bytes += sta_get_stats_bytes(cpurxs);
                        }
                }

                sinfo->filled |= BIT_ULL(NL80211_STA_INFO_RX_BYTES64);
        }

        if (!(sinfo->filled & BIT_ULL(NL80211_STA_INFO_RX_PACKETS))) {
                sinfo->rx_packets = sta->deflink.rx_stats.packets;
                if (sta->deflink.pcpu_rx_stats) {
                        for_each_possible_cpu(cpu) {
                                struct ieee80211_sta_rx_stats *cpurxs;

                                cpurxs = per_cpu_ptr(sta->deflink.pcpu_rx_stats,
                                                     cpu);
                                sinfo->rx_packets += cpurxs->packets;
                        }
                }
                sinfo->filled |= BIT_ULL(NL80211_STA_INFO_RX_PACKETS);
        }

        if (!(sinfo->filled & BIT_ULL(NL80211_STA_INFO_TX_RETRIES))) {
                sinfo->tx_retries = sta->deflink.status_stats.retry_count;
                sinfo->filled |= BIT_ULL(NL80211_STA_INFO_TX_RETRIES);
        }

        if (!(sinfo->filled & BIT_ULL(NL80211_STA_INFO_TX_FAILED))) {
                sinfo->tx_failed = sta->deflink.status_stats.retry_failed;
                sinfo->filled |= BIT_ULL(NL80211_STA_INFO_TX_FAILED);
        }

        if (!(sinfo->filled & BIT_ULL(NL80211_STA_INFO_RX_DURATION))) {
                for (ac = 0; ac < IEEE80211_NUM_ACS; ac++)
                        sinfo->rx_duration += sta->airtime[ac].rx_airtime;
                sinfo->filled |= BIT_ULL(NL80211_STA_INFO_RX_DURATION);
        }

        if (!(sinfo->filled & BIT_ULL(NL80211_STA_INFO_TX_DURATION))) {
                for (ac = 0; ac < IEEE80211_NUM_ACS; ac++)
                        sinfo->tx_duration += sta->airtime[ac].tx_airtime;
                sinfo->filled |= BIT_ULL(NL80211_STA_INFO_TX_DURATION);
        }

        if (!(sinfo->filled & BIT_ULL(NL80211_STA_INFO_AIRTIME_WEIGHT))) {
                sinfo->airtime_weight = sta->airtime_weight;
                sinfo->filled |= BIT_ULL(NL80211_STA_INFO_AIRTIME_WEIGHT);
        }

        sinfo->rx_dropped_misc = sta->deflink.rx_stats.dropped;
        if (sta->deflink.pcpu_rx_stats) {
                for_each_possible_cpu(cpu) {
                        struct ieee80211_sta_rx_stats *cpurxs;

                        cpurxs = per_cpu_ptr(sta->deflink.pcpu_rx_stats, cpu);
                        sinfo->rx_dropped_misc += cpurxs->dropped;
                }
        }

        if (sdata->vif.type == NL80211_IFTYPE_STATION &&
            !(sdata->vif.driver_flags & IEEE80211_VIF_BEACON_FILTER)) {
                sinfo->filled |= BIT_ULL(NL80211_STA_INFO_BEACON_RX) |
                                 BIT_ULL(NL80211_STA_INFO_BEACON_SIGNAL_AVG);
                sinfo->rx_beacon_signal_avg = ieee80211_ave_rssi(&sdata->vif);
        }

        if (ieee80211_hw_check(&sta->local->hw, SIGNAL_DBM) ||
            ieee80211_hw_check(&sta->local->hw, SIGNAL_UNSPEC)) {
                if (!(sinfo->filled & BIT_ULL(NL80211_STA_INFO_SIGNAL))) {
                        sinfo->signal = (s8)last_rxstats->last_signal;
                        sinfo->filled |= BIT_ULL(NL80211_STA_INFO_SIGNAL);
                }

                if (!sta->deflink.pcpu_rx_stats &&
                    !(sinfo->filled & BIT_ULL(NL80211_STA_INFO_SIGNAL_AVG))) {
                        sinfo->signal_avg =
                                -ewma_signal_read(&sta->deflink.rx_stats_avg.signal);
                        sinfo->filled |= BIT_ULL(NL80211_STA_INFO_SIGNAL_AVG);
                }
        }

        /* for the average - if pcpu_rx_stats isn't set - rxstats must point to
         * the sta->rx_stats struct, so the check here is fine with and without
         * pcpu statistics
         */
        if (last_rxstats->chains &&
            !(sinfo->filled & (BIT_ULL(NL80211_STA_INFO_CHAIN_SIGNAL) |
                               BIT_ULL(NL80211_STA_INFO_CHAIN_SIGNAL_AVG)))) {
                sinfo->filled |= BIT_ULL(NL80211_STA_INFO_CHAIN_SIGNAL);
                if (!sta->deflink.pcpu_rx_stats)
                        sinfo->filled |= BIT_ULL(NL80211_STA_INFO_CHAIN_SIGNAL_AVG);

                sinfo->chains = last_rxstats->chains;

                for (i = 0; i < ARRAY_SIZE(sinfo->chain_signal); i++) {
                        sinfo->chain_signal[i] =
                                last_rxstats->chain_signal_last[i];
                        sinfo->chain_signal_avg[i] =
                                -ewma_signal_read(&sta->deflink.rx_stats_avg.chain_signal[i]);
                }
        }

        if (!(sinfo->filled & BIT_ULL(NL80211_STA_INFO_TX_BITRATE)) &&
            !sta->sta.valid_links) {
                sta_set_rate_info_tx(sta, &sta->deflink.tx_stats.last_rate,
                                     &sinfo->txrate);
                sinfo->filled |= BIT_ULL(NL80211_STA_INFO_TX_BITRATE);
        }

        if (!(sinfo->filled & BIT_ULL(NL80211_STA_INFO_RX_BITRATE)) &&
            !sta->sta.valid_links) {
                if (sta_set_rate_info_rx(sta, &sinfo->rxrate) == 0)
                        sinfo->filled |= BIT_ULL(NL80211_STA_INFO_RX_BITRATE);
        }

        if (tidstats && !cfg80211_sinfo_alloc_tid_stats(sinfo, GFP_KERNEL)) {
                for (i = 0; i < IEEE80211_NUM_TIDS + 1; i++)
                        sta_set_tidstats(sta, &sinfo->pertid[i], i);
        }

        if (ieee80211_vif_is_mesh(&sdata->vif)) {
#ifdef CONFIG_MAC80211_MESH
                sinfo->filled |= BIT_ULL(NL80211_STA_INFO_LLID) |
                                 BIT_ULL(NL80211_STA_INFO_PLID) |
                                 BIT_ULL(NL80211_STA_INFO_PLINK_STATE) |
                                 BIT_ULL(NL80211_STA_INFO_LOCAL_PM) |
                                 BIT_ULL(NL80211_STA_INFO_PEER_PM) |
                                 BIT_ULL(NL80211_STA_INFO_NONPEER_PM) |
                                 BIT_ULL(NL80211_STA_INFO_CONNECTED_TO_GATE) |
                                 BIT_ULL(NL80211_STA_INFO_CONNECTED_TO_AS);

                sinfo->llid = sta->mesh->llid;
                sinfo->plid = sta->mesh->plid;
                sinfo->plink_state = sta->mesh->plink_state;
                if (test_sta_flag(sta, WLAN_STA_TOFFSET_KNOWN)) {
                        sinfo->filled |= BIT_ULL(NL80211_STA_INFO_T_OFFSET);
                        sinfo->t_offset = sta->mesh->t_offset;
                }
                sinfo->local_pm = sta->mesh->local_pm;
                sinfo->peer_pm = sta->mesh->peer_pm;
                sinfo->nonpeer_pm = sta->mesh->nonpeer_pm;
                sinfo->connected_to_gate = sta->mesh->connected_to_gate;
                sinfo->connected_to_as = sta->mesh->connected_to_as;
#endif
        }

        sinfo->bss_param.flags = 0;
        if (sdata->vif.bss_conf.use_cts_prot)
                sinfo->bss_param.flags |= BSS_PARAM_FLAGS_CTS_PROT;
        if (sdata->vif.bss_conf.use_short_preamble)
                sinfo->bss_param.flags |= BSS_PARAM_FLAGS_SHORT_PREAMBLE;
        if (sdata->vif.bss_conf.use_short_slot)
                sinfo->bss_param.flags |= BSS_PARAM_FLAGS_SHORT_SLOT_TIME;
        sinfo->bss_param.dtim_period = sdata->vif.bss_conf.dtim_period;
        sinfo->bss_param.beacon_interval = sdata->vif.bss_conf.beacon_int;

        sinfo->sta_flags.set = 0;
        sinfo->sta_flags.mask = BIT(NL80211_STA_FLAG_AUTHORIZED) |
                                BIT(NL80211_STA_FLAG_SHORT_PREAMBLE) |
                                BIT(NL80211_STA_FLAG_WME) |
                                BIT(NL80211_STA_FLAG_MFP) |
                                BIT(NL80211_STA_FLAG_AUTHENTICATED) |
                                BIT(NL80211_STA_FLAG_ASSOCIATED) |
                                BIT(NL80211_STA_FLAG_TDLS_PEER);
        if (test_sta_flag(sta, WLAN_STA_AUTHORIZED))
                sinfo->sta_flags.set |= BIT(NL80211_STA_FLAG_AUTHORIZED);
        if (test_sta_flag(sta, WLAN_STA_SHORT_PREAMBLE))
                sinfo->sta_flags.set |= BIT(NL80211_STA_FLAG_SHORT_PREAMBLE);
        if (sta->sta.wme)
                sinfo->sta_flags.set |= BIT(NL80211_STA_FLAG_WME);
        if (test_sta_flag(sta, WLAN_STA_MFP))
                sinfo->sta_flags.set |= BIT(NL80211_STA_FLAG_MFP);
        if (test_sta_flag(sta, WLAN_STA_AUTH))
                sinfo->sta_flags.set |= BIT(NL80211_STA_FLAG_AUTHENTICATED);
        if (test_sta_flag(sta, WLAN_STA_ASSOC))
                sinfo->sta_flags.set |= BIT(NL80211_STA_FLAG_ASSOCIATED);
        if (test_sta_flag(sta, WLAN_STA_TDLS_PEER))
                sinfo->sta_flags.set |= BIT(NL80211_STA_FLAG_TDLS_PEER);

        thr = sta_get_expected_throughput(sta);

        if (thr != 0) {
                sinfo->filled |= BIT_ULL(NL80211_STA_INFO_EXPECTED_THROUGHPUT);
                sinfo->expected_throughput = thr;
        }

        if (!(sinfo->filled & BIT_ULL(NL80211_STA_INFO_ACK_SIGNAL)) &&
            sta->deflink.status_stats.ack_signal_filled) {
                sinfo->ack_signal = sta->deflink.status_stats.last_ack_signal;
                sinfo->filled |= BIT_ULL(NL80211_STA_INFO_ACK_SIGNAL);
        }

        if (!(sinfo->filled & BIT_ULL(NL80211_STA_INFO_ACK_SIGNAL_AVG)) &&
            sta->deflink.status_stats.ack_signal_filled) {
                sinfo->avg_ack_signal =
                        -(s8)ewma_avg_signal_read(
                                &sta->deflink.status_stats.avg_ack_signal);
                sinfo->filled |=
                        BIT_ULL(NL80211_STA_INFO_ACK_SIGNAL_AVG);
        }

        if (ieee80211_vif_is_mesh(&sdata->vif)) {
                sinfo->filled |= BIT_ULL(NL80211_STA_INFO_AIRTIME_LINK_METRIC);
                sinfo->airtime_link_metric =
                        airtime_link_metric_get(local, sta);
        }
}

u32 sta_get_expected_throughput(struct sta_info *sta)
{
        struct ieee80211_sub_if_data *sdata = sta->sdata;
        struct ieee80211_local *local = sdata->local;
        struct rate_control_ref *ref = NULL;
        u32 thr = 0;

        if (test_sta_flag(sta, WLAN_STA_RATE_CONTROL))
                ref = local->rate_ctrl;

        /* check if the driver has a SW RC implementation */
        if (ref && ref->ops->get_expected_throughput)
                thr = ref->ops->get_expected_throughput(sta->rate_ctrl_priv);
        else
                thr = drv_get_expected_throughput(local, sta);

        return thr;
}

unsigned long ieee80211_sta_last_active(struct sta_info *sta)
{
        struct ieee80211_sta_rx_stats *stats = sta_get_last_rx_stats(sta);

        if (!sta->deflink.status_stats.last_ack ||
            time_after(stats->last_rx, sta->deflink.status_stats.last_ack))
                return stats->last_rx;
        return sta->deflink.status_stats.last_ack;
}

static void sta_update_codel_params(struct sta_info *sta, u32 thr)
{
        if (!sta->sdata->local->ops->wake_tx_queue)
                return;

        if (thr && thr < STA_SLOW_THRESHOLD * sta->local->num_sta) {
                sta->cparams.target = MS2TIME(50);
                sta->cparams.interval = MS2TIME(300);
                sta->cparams.ecn = false;
        } else {
                sta->cparams.target = MS2TIME(20);
                sta->cparams.interval = MS2TIME(100);
                sta->cparams.ecn = true;
        }
}

void ieee80211_sta_set_expected_throughput(struct ieee80211_sta *pubsta,
                                           u32 thr)
{
        struct sta_info *sta = container_of(pubsta, struct sta_info, sta);

        sta_update_codel_params(sta, thr);
}

int ieee80211_sta_allocate_link(struct sta_info *sta, unsigned int link_id)
{
        struct ieee80211_sub_if_data *sdata = sta->sdata;
        struct sta_link_alloc *alloc;
        int ret;

        lockdep_assert_held(&sdata->local->sta_mtx);

        /* must represent an MLD from the start */
        if (WARN_ON(!sta->sta.valid_links))
                return -EINVAL;

        if (WARN_ON(sta->sta.valid_links & BIT(link_id) ||
                    sta->link[link_id]))
                return -EBUSY;

        alloc = kzalloc(sizeof(*alloc), GFP_KERNEL);
        if (!alloc)
                return -ENOMEM;

        ret = sta_info_alloc_link(sdata->local, &alloc->info, GFP_KERNEL);
        if (ret) {
                kfree(alloc);
                return ret;
        }

        sta_info_add_link(sta, link_id, &alloc->info, &alloc->sta);

        return 0;
}

void ieee80211_sta_free_link(struct sta_info *sta, unsigned int link_id)
{
        lockdep_assert_held(&sta->sdata->local->sta_mtx);

        sta_remove_link(sta, link_id, false);
}

int ieee80211_sta_activate_link(struct sta_info *sta, unsigned int link_id)
{
        struct ieee80211_sub_if_data *sdata = sta->sdata;
        struct link_sta_info *link_sta;
        u16 old_links = sta->sta.valid_links;
        u16 new_links = old_links | BIT(link_id);
        int ret;

        link_sta = rcu_dereference_protected(sta->link[link_id],
                                             lockdep_is_held(&sdata->local->sta_mtx));

        if (WARN_ON(old_links == new_links || !link_sta))
                return -EINVAL;

        rcu_read_lock();
        if (link_sta_info_hash_lookup(sdata->local, link_sta->addr)) {
                rcu_read_unlock();
                return -EALREADY;
        }
        /* we only modify under the mutex so this is fine */
        rcu_read_unlock();

        sta->sta.valid_links = new_links;

        if (!test_sta_flag(sta, WLAN_STA_INSERTED)) {
                ret = 0;
                goto hash;
        }

        ret = drv_change_sta_links(sdata->local, sdata, &sta->sta,
                                   old_links, new_links);
        if (ret) {
                sta->sta.valid_links = old_links;
                sta_remove_link(sta, link_id, false);
                return ret;
        }

hash:
        ret = link_sta_info_hash_add(sdata->local, link_sta);
        WARN_ON(ret);
        return 0;
}

void ieee80211_sta_remove_link(struct sta_info *sta, unsigned int link_id)
{
        struct ieee80211_sub_if_data *sdata = sta->sdata;

        lockdep_assert_held(&sdata->local->sta_mtx);

        sta->sta.valid_links &= ~BIT(link_id);

        if (test_sta_flag(sta, WLAN_STA_INSERTED))
                drv_change_sta_links(sdata->local, sdata, &sta->sta,
                                     sta->sta.valid_links,
                                     sta->sta.valid_links & ~BIT(link_id));

        sta_remove_link(sta, link_id, true);
}

void ieee80211_sta_set_max_amsdu_subframes(struct sta_info *sta,
                                           const u8 *ext_capab,
                                           unsigned int ext_capab_len)
{
        u8 val;

        sta->sta.max_amsdu_subframes = 0;

        if (ext_capab_len < 8)
                return;

        /* The sender might not have sent the last bit, consider it to be 0 */
        val = u8_get_bits(ext_capab[7], WLAN_EXT_CAPA8_MAX_MSDU_IN_AMSDU_LSB);

        /* we did get all the bits, take the MSB as well */
        if (ext_capab_len >= 9)
                val |= u8_get_bits(ext_capab[8],
                                   WLAN_EXT_CAPA9_MAX_MSDU_IN_AMSDU_MSB) << 1;

        if (val)
                sta->sta.max_amsdu_subframes = 4 << val;
}