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linux/net/mac80211/sta_info.c
Johannes Berg 07346f81e8 mac80211: proper STA info locking
As discussed earlier, we can unify locking in struct sta_info
and use just a single spinlock protecting all members of the
structure that need protection. Many don't, but one of the
especially bad ones is the 'flags' member that can currently
be clobbered when RX and TX is being processed on different
CPUs at the same time.

Because having four spinlocks for different, mostly exclusive
parts of a single structure is overkill, this patch also kills
the ampdu and mesh plink spinlocks and uses just a single one
for everything. Because none of the spinlocks are nested, this
is safe.

It remains to be seen whether or not we should make the sta
flags use atomic bit operations instead, for now though this
is a safe thing and using atomic operations instead will be
very simple using the new static inline functions this patch
introduces for accessing sta->flags.

Since spin_lock_bh() is used with this lock, there shouldn't
be any contention even if aggregation is enabled at around the
same time as both requires frame transmission/reception which
is in a bh context.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Cc: Tomas Winkler <tomasw@gmail.com>
Cc: Ron Rindjunsky <ron.rindjunsky@intel.com>
Cc: Luis Carlos Cobo <luisca@cozybit.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2008-05-14 16:29:34 -04:00

788 lines
21 KiB
C

/*
* Copyright 2002-2005, Instant802 Networks, Inc.
* Copyright 2006-2007 Jiri Benc <jbenc@suse.cz>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/module.h>
#include <linux/init.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/mac80211.h>
#include "ieee80211_i.h"
#include "rate.h"
#include "sta_info.h"
#include "debugfs_sta.h"
#include "mesh.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 either destroy it using sta_info_destroy()
* (which is pretty useless) or insert it into the hash table using
* sta_info_insert() which demotes the reference from ownership to a regular
* RCU-protected reference; if the function is called without protection by an
* RCU critical section the reference is instantly invalidated. 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()!
*
* Because there are debugfs entries for each station, and adding those
* must be able to sleep, it is also possible to "pin" a station entry,
* that means it can be removed from the hash table but not be freed.
* See the comment in __sta_info_unlink() for more information, this is
* an internal capability only.
*
* In order to remove a STA info structure, the caller needs to first
* unlink it (sta_info_unlink()) from the list and hash tables and
* then destroy it; sta_info_destroy() will wait for an RCU grace period
* to elapse before actually freeing it. Due to the pinning and the
* possibility of multiple callers trying to remove the same STA info at
* the same time, sta_info_unlink() can clear the STA info pointer it is
* passed to indicate that the STA info is owned by somebody else now.
*
* If sta_info_unlink() did not clear the pointer then the caller owns
* the STA info structure now and is responsible of destroying it with
* a call to sta_info_destroy().
*
* In all other cases, 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.
*/
/* Caller must hold local->sta_lock */
static int sta_info_hash_del(struct ieee80211_local *local,
struct sta_info *sta)
{
struct sta_info *s;
s = local->sta_hash[STA_HASH(sta->addr)];
if (!s)
return -ENOENT;
if (s == sta) {
rcu_assign_pointer(local->sta_hash[STA_HASH(sta->addr)],
s->hnext);
return 0;
}
while (s->hnext && s->hnext != sta)
s = s->hnext;
if (s->hnext) {
rcu_assign_pointer(s->hnext, sta->hnext);
return 0;
}
return -ENOENT;
}
/* protected by RCU */
static struct sta_info *__sta_info_find(struct ieee80211_local *local,
u8 *addr)
{
struct sta_info *sta;
sta = rcu_dereference(local->sta_hash[STA_HASH(addr)]);
while (sta) {
if (compare_ether_addr(sta->addr, addr) == 0)
break;
sta = rcu_dereference(sta->hnext);
}
return sta;
}
struct sta_info *sta_info_get(struct ieee80211_local *local, u8 *addr)
{
return __sta_info_find(local, addr);
}
EXPORT_SYMBOL(sta_info_get);
struct sta_info *sta_info_get_by_idx(struct ieee80211_local *local, int idx,
struct net_device *dev)
{
struct sta_info *sta;
int i = 0;
list_for_each_entry_rcu(sta, &local->sta_list, list) {
if (dev && dev != sta->sdata->dev)
continue;
if (i < idx) {
++i;
continue;
}
return sta;
}
return NULL;
}
/**
* __sta_info_free - internal STA free helper
*
* @sta: STA info to free
*
* This function must undo everything done by sta_info_alloc()
* that may happen before sta_info_insert().
*/
static void __sta_info_free(struct ieee80211_local *local,
struct sta_info *sta)
{
DECLARE_MAC_BUF(mbuf);
rate_control_free_sta(sta->rate_ctrl, sta->rate_ctrl_priv);
rate_control_put(sta->rate_ctrl);
#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
printk(KERN_DEBUG "%s: Destroyed STA %s\n",
wiphy_name(local->hw.wiphy), print_mac(mbuf, sta->addr));
#endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
kfree(sta);
}
void sta_info_destroy(struct sta_info *sta)
{
struct ieee80211_local *local;
struct sk_buff *skb;
int i;
might_sleep();
if (!sta)
return;
local = sta->local;
rate_control_remove_sta_debugfs(sta);
ieee80211_sta_debugfs_remove(sta);
#ifdef CONFIG_MAC80211_MESH
if (ieee80211_vif_is_mesh(&sta->sdata->vif))
mesh_plink_deactivate(sta);
#endif
/*
* We have only unlinked the key, and actually destroying it
* may mean it is removed from hardware which requires that
* the key->sta pointer is still valid, so flush the key todo
* list here.
*
* ieee80211_key_todo() will synchronize_rcu() so after this
* nothing can reference this sta struct any more.
*/
ieee80211_key_todo();
#ifdef CONFIG_MAC80211_MESH
if (ieee80211_vif_is_mesh(&sta->sdata->vif))
del_timer_sync(&sta->plink_timer);
#endif
while ((skb = skb_dequeue(&sta->ps_tx_buf)) != NULL) {
local->total_ps_buffered--;
dev_kfree_skb_any(skb);
}
while ((skb = skb_dequeue(&sta->tx_filtered)) != NULL)
dev_kfree_skb_any(skb);
for (i = 0; i < STA_TID_NUM; i++) {
spin_lock_bh(&sta->lock);
if (sta->ampdu_mlme.tid_rx[i])
del_timer_sync(&sta->ampdu_mlme.tid_rx[i]->session_timer);
if (sta->ampdu_mlme.tid_tx[i])
del_timer_sync(&sta->ampdu_mlme.tid_tx[i]->addba_resp_timer);
spin_unlock_bh(&sta->lock);
}
__sta_info_free(local, sta);
}
/* Caller must hold local->sta_lock */
static void sta_info_hash_add(struct ieee80211_local *local,
struct sta_info *sta)
{
sta->hnext = local->sta_hash[STA_HASH(sta->addr)];
rcu_assign_pointer(local->sta_hash[STA_HASH(sta->addr)], sta);
}
struct sta_info *sta_info_alloc(struct ieee80211_sub_if_data *sdata,
u8 *addr, gfp_t gfp)
{
struct ieee80211_local *local = sdata->local;
struct sta_info *sta;
int i;
DECLARE_MAC_BUF(mbuf);
sta = kzalloc(sizeof(*sta), gfp);
if (!sta)
return NULL;
spin_lock_init(&sta->lock);
memcpy(sta->addr, addr, ETH_ALEN);
sta->local = local;
sta->sdata = sdata;
sta->rate_ctrl = rate_control_get(local->rate_ctrl);
sta->rate_ctrl_priv = rate_control_alloc_sta(sta->rate_ctrl,
gfp);
if (!sta->rate_ctrl_priv) {
rate_control_put(sta->rate_ctrl);
kfree(sta);
return NULL;
}
for (i = 0; i < STA_TID_NUM; i++) {
/* timer_to_tid must be initialized with identity mapping to
* enable session_timer's data differentiation. refer to
* sta_rx_agg_session_timer_expired for useage */
sta->timer_to_tid[i] = i;
/* tid to tx queue: initialize according to HW (0 is valid) */
sta->tid_to_tx_q[i] = local->hw.queues + local->hw.ampdu_queues;
/* rx */
sta->ampdu_mlme.tid_state_rx[i] = HT_AGG_STATE_IDLE;
sta->ampdu_mlme.tid_rx[i] = NULL;
/* tx */
sta->ampdu_mlme.tid_state_tx[i] = HT_AGG_STATE_IDLE;
sta->ampdu_mlme.tid_tx[i] = NULL;
sta->ampdu_mlme.addba_req_num[i] = 0;
}
skb_queue_head_init(&sta->ps_tx_buf);
skb_queue_head_init(&sta->tx_filtered);
#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
printk(KERN_DEBUG "%s: Allocated STA %s\n",
wiphy_name(local->hw.wiphy), print_mac(mbuf, sta->addr));
#endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
#ifdef CONFIG_MAC80211_MESH
sta->plink_state = PLINK_LISTEN;
init_timer(&sta->plink_timer);
#endif
return sta;
}
int sta_info_insert(struct sta_info *sta)
{
struct ieee80211_local *local = sta->local;
struct ieee80211_sub_if_data *sdata = sta->sdata;
unsigned long flags;
int err = 0;
DECLARE_MAC_BUF(mac);
/*
* 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(!netif_running(sdata->dev))) {
err = -ENETDOWN;
goto out_free;
}
if (WARN_ON(compare_ether_addr(sta->addr, sdata->dev->dev_addr) == 0 ||
is_multicast_ether_addr(sta->addr))) {
err = -EINVAL;
goto out_free;
}
spin_lock_irqsave(&local->sta_lock, flags);
/* check if STA exists already */
if (__sta_info_find(local, sta->addr)) {
spin_unlock_irqrestore(&local->sta_lock, flags);
err = -EEXIST;
goto out_free;
}
list_add(&sta->list, &local->sta_list);
local->num_sta++;
sta_info_hash_add(local, sta);
/* notify driver */
if (local->ops->sta_notify) {
if (sdata->vif.type == IEEE80211_IF_TYPE_VLAN)
sdata = sdata->u.vlan.ap;
local->ops->sta_notify(local_to_hw(local), &sdata->vif,
STA_NOTIFY_ADD, sta->addr);
}
#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
printk(KERN_DEBUG "%s: Inserted STA %s\n",
wiphy_name(local->hw.wiphy), print_mac(mac, sta->addr));
#endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
spin_unlock_irqrestore(&local->sta_lock, flags);
#ifdef CONFIG_MAC80211_DEBUGFS
/*
* Debugfs entry adding might sleep, so schedule process
* context task for adding entry for STAs that do not yet
* have one.
* NOTE: due to auto-freeing semantics this may only be done
* if the insertion is successful!
*/
schedule_work(&local->sta_debugfs_add);
#endif
if (ieee80211_vif_is_mesh(&sdata->vif))
mesh_accept_plinks_update(sdata);
return 0;
out_free:
BUG_ON(!err);
__sta_info_free(local, sta);
return err;
}
static inline void __bss_tim_set(struct ieee80211_if_ap *bss, u16 aid)
{
/*
* This format has been mandated by the IEEE specifications,
* so this line may not be changed to use the __set_bit() format.
*/
bss->tim[aid / 8] |= (1 << (aid % 8));
}
static inline void __bss_tim_clear(struct ieee80211_if_ap *bss, u16 aid)
{
/*
* This format has been mandated by the IEEE specifications,
* so this line may not be changed to use the __clear_bit() format.
*/
bss->tim[aid / 8] &= ~(1 << (aid % 8));
}
static void __sta_info_set_tim_bit(struct ieee80211_if_ap *bss,
struct sta_info *sta)
{
if (bss)
__bss_tim_set(bss, sta->aid);
if (sta->local->ops->set_tim) {
sta->local->tim_in_locked_section = true;
sta->local->ops->set_tim(local_to_hw(sta->local), sta->aid, 1);
sta->local->tim_in_locked_section = false;
}
}
void sta_info_set_tim_bit(struct sta_info *sta)
{
unsigned long flags;
spin_lock_irqsave(&sta->local->sta_lock, flags);
__sta_info_set_tim_bit(sta->sdata->bss, sta);
spin_unlock_irqrestore(&sta->local->sta_lock, flags);
}
static void __sta_info_clear_tim_bit(struct ieee80211_if_ap *bss,
struct sta_info *sta)
{
if (bss)
__bss_tim_clear(bss, sta->aid);
if (sta->local->ops->set_tim) {
sta->local->tim_in_locked_section = true;
sta->local->ops->set_tim(local_to_hw(sta->local), sta->aid, 0);
sta->local->tim_in_locked_section = false;
}
}
void sta_info_clear_tim_bit(struct sta_info *sta)
{
unsigned long flags;
spin_lock_irqsave(&sta->local->sta_lock, flags);
__sta_info_clear_tim_bit(sta->sdata->bss, sta);
spin_unlock_irqrestore(&sta->local->sta_lock, flags);
}
void __sta_info_unlink(struct sta_info **sta)
{
struct ieee80211_local *local = (*sta)->local;
struct ieee80211_sub_if_data *sdata = (*sta)->sdata;
#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
DECLARE_MAC_BUF(mbuf);
#endif
/*
* pull caller's reference if we're already gone.
*/
if (sta_info_hash_del(local, *sta)) {
*sta = NULL;
return;
}
if ((*sta)->key) {
ieee80211_key_free((*sta)->key);
WARN_ON((*sta)->key);
}
list_del(&(*sta)->list);
if (test_and_clear_sta_flags(*sta, WLAN_STA_PS)) {
if (sdata->bss)
atomic_dec(&sdata->bss->num_sta_ps);
__sta_info_clear_tim_bit(sdata->bss, *sta);
}
local->num_sta--;
if (local->ops->sta_notify) {
if (sdata->vif.type == IEEE80211_IF_TYPE_VLAN)
sdata = sdata->u.vlan.ap;
local->ops->sta_notify(local_to_hw(local), &sdata->vif,
STA_NOTIFY_REMOVE, (*sta)->addr);
}
if (ieee80211_vif_is_mesh(&sdata->vif)) {
mesh_accept_plinks_update(sdata);
#ifdef CONFIG_MAC80211_MESH
del_timer(&(*sta)->plink_timer);
#endif
}
#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
printk(KERN_DEBUG "%s: Removed STA %s\n",
wiphy_name(local->hw.wiphy), print_mac(mbuf, (*sta)->addr));
#endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
/*
* Finally, pull caller's reference if the STA is pinned by the
* task that is adding the debugfs entries. In that case, we
* leave the STA "to be freed".
*
* The rules are not trivial, but not too complex either:
* (1) pin_status is only modified under the sta_lock
* (2) STAs may only be pinned under the RTNL so that
* sta_info_flush() is guaranteed to actually destroy
* all STAs that are active for a given interface, this
* is required for correctness because otherwise we
* could notify a driver that an interface is going
* away and only after that (!) notify it about a STA
* on that interface going away.
* (3) sta_info_debugfs_add_work() will set the status
* to PINNED when it found an item that needs a new
* debugfs directory created. In that case, that item
* must not be freed although all *RCU* users are done
* with it. Hence, we tell the caller of _unlink()
* that the item is already gone (as can happen when
* two tasks try to unlink/destroy at the same time)
* (4) We set the pin_status to DESTROY here when we
* find such an item.
* (5) sta_info_debugfs_add_work() will reset the pin_status
* from PINNED to NORMAL when it is done with the item,
* but will check for DESTROY before resetting it in
* which case it will free the item.
*/
if ((*sta)->pin_status == STA_INFO_PIN_STAT_PINNED) {
(*sta)->pin_status = STA_INFO_PIN_STAT_DESTROY;
*sta = NULL;
return;
}
}
void sta_info_unlink(struct sta_info **sta)
{
struct ieee80211_local *local = (*sta)->local;
unsigned long flags;
spin_lock_irqsave(&local->sta_lock, flags);
__sta_info_unlink(sta);
spin_unlock_irqrestore(&local->sta_lock, flags);
}
static inline int sta_info_buffer_expired(struct ieee80211_local *local,
struct sta_info *sta,
struct sk_buff *skb)
{
struct ieee80211_tx_packet_data *pkt_data;
int timeout;
if (!skb)
return 0;
pkt_data = (struct ieee80211_tx_packet_data *) skb->cb;
/* Timeout: (2 * listen_interval * beacon_int * 1024 / 1000000) sec */
timeout = (sta->listen_interval * local->hw.conf.beacon_int * 32 /
15625) * HZ;
if (timeout < STA_TX_BUFFER_EXPIRE)
timeout = STA_TX_BUFFER_EXPIRE;
return time_after(jiffies, pkt_data->jiffies + timeout);
}
static void sta_info_cleanup_expire_buffered(struct ieee80211_local *local,
struct sta_info *sta)
{
unsigned long flags;
struct sk_buff *skb;
struct ieee80211_sub_if_data *sdata;
DECLARE_MAC_BUF(mac);
if (skb_queue_empty(&sta->ps_tx_buf))
return;
for (;;) {
spin_lock_irqsave(&sta->ps_tx_buf.lock, flags);
skb = skb_peek(&sta->ps_tx_buf);
if (sta_info_buffer_expired(local, sta, skb))
skb = __skb_dequeue(&sta->ps_tx_buf);
else
skb = NULL;
spin_unlock_irqrestore(&sta->ps_tx_buf.lock, flags);
if (!skb)
break;
sdata = sta->sdata;
local->total_ps_buffered--;
printk(KERN_DEBUG "Buffered frame expired (STA "
"%s)\n", print_mac(mac, sta->addr));
dev_kfree_skb(skb);
if (skb_queue_empty(&sta->ps_tx_buf))
sta_info_clear_tim_bit(sta);
}
}
static void sta_info_cleanup(unsigned long data)
{
struct ieee80211_local *local = (struct ieee80211_local *) data;
struct sta_info *sta;
rcu_read_lock();
list_for_each_entry_rcu(sta, &local->sta_list, list)
sta_info_cleanup_expire_buffered(local, sta);
rcu_read_unlock();
local->sta_cleanup.expires =
round_jiffies(jiffies + STA_INFO_CLEANUP_INTERVAL);
add_timer(&local->sta_cleanup);
}
#ifdef CONFIG_MAC80211_DEBUGFS
/*
* See comment in __sta_info_unlink,
* caller must hold local->sta_lock.
*/
static void __sta_info_pin(struct sta_info *sta)
{
WARN_ON(sta->pin_status != STA_INFO_PIN_STAT_NORMAL);
sta->pin_status = STA_INFO_PIN_STAT_PINNED;
}
/*
* See comment in __sta_info_unlink, returns sta if it
* needs to be destroyed.
*/
static struct sta_info *__sta_info_unpin(struct sta_info *sta)
{
struct sta_info *ret = NULL;
unsigned long flags;
spin_lock_irqsave(&sta->local->sta_lock, flags);
WARN_ON(sta->pin_status != STA_INFO_PIN_STAT_DESTROY &&
sta->pin_status != STA_INFO_PIN_STAT_PINNED);
if (sta->pin_status == STA_INFO_PIN_STAT_DESTROY)
ret = sta;
sta->pin_status = STA_INFO_PIN_STAT_NORMAL;
spin_unlock_irqrestore(&sta->local->sta_lock, flags);
return ret;
}
static void sta_info_debugfs_add_work(struct work_struct *work)
{
struct ieee80211_local *local =
container_of(work, struct ieee80211_local, sta_debugfs_add);
struct sta_info *sta, *tmp;
unsigned long flags;
/* We need to keep the RTNL across the whole pinned status. */
rtnl_lock();
while (1) {
sta = NULL;
spin_lock_irqsave(&local->sta_lock, flags);
list_for_each_entry(tmp, &local->sta_list, list) {
if (!tmp->debugfs.dir) {
sta = tmp;
__sta_info_pin(sta);
break;
}
}
spin_unlock_irqrestore(&local->sta_lock, flags);
if (!sta)
break;
ieee80211_sta_debugfs_add(sta);
rate_control_add_sta_debugfs(sta);
sta = __sta_info_unpin(sta);
sta_info_destroy(sta);
}
rtnl_unlock();
}
#endif
static void __ieee80211_run_pending_flush(struct ieee80211_local *local)
{
struct sta_info *sta;
unsigned long flags;
ASSERT_RTNL();
spin_lock_irqsave(&local->sta_lock, flags);
while (!list_empty(&local->sta_flush_list)) {
sta = list_first_entry(&local->sta_flush_list,
struct sta_info, list);
list_del(&sta->list);
spin_unlock_irqrestore(&local->sta_lock, flags);
sta_info_destroy(sta);
spin_lock_irqsave(&local->sta_lock, flags);
}
spin_unlock_irqrestore(&local->sta_lock, flags);
}
static void ieee80211_sta_flush_work(struct work_struct *work)
{
struct ieee80211_local *local =
container_of(work, struct ieee80211_local, sta_flush_work);
rtnl_lock();
__ieee80211_run_pending_flush(local);
rtnl_unlock();
}
void sta_info_init(struct ieee80211_local *local)
{
spin_lock_init(&local->sta_lock);
INIT_LIST_HEAD(&local->sta_list);
INIT_LIST_HEAD(&local->sta_flush_list);
INIT_WORK(&local->sta_flush_work, ieee80211_sta_flush_work);
setup_timer(&local->sta_cleanup, sta_info_cleanup,
(unsigned long)local);
local->sta_cleanup.expires =
round_jiffies(jiffies + STA_INFO_CLEANUP_INTERVAL);
#ifdef CONFIG_MAC80211_DEBUGFS
INIT_WORK(&local->sta_debugfs_add, sta_info_debugfs_add_work);
#endif
}
int sta_info_start(struct ieee80211_local *local)
{
add_timer(&local->sta_cleanup);
return 0;
}
void sta_info_stop(struct ieee80211_local *local)
{
del_timer(&local->sta_cleanup);
cancel_work_sync(&local->sta_flush_work);
#ifdef CONFIG_MAC80211_DEBUGFS
/*
* Make sure the debugfs adding work isn't pending after this
* because we're about to be destroyed. It doesn't matter
* whether it ran or not since we're going to flush all STAs
* anyway.
*/
cancel_work_sync(&local->sta_debugfs_add);
#endif
rtnl_lock();
sta_info_flush(local, NULL);
__ieee80211_run_pending_flush(local);
rtnl_unlock();
}
/**
* sta_info_flush - flush matching STA entries from the STA table
*
* Returns the number of removed STA entries.
*
* @local: local interface data
* @sdata: matching rule for the net device (sta->dev) or %NULL to match all STAs
*/
int sta_info_flush(struct ieee80211_local *local,
struct ieee80211_sub_if_data *sdata)
{
struct sta_info *sta, *tmp;
LIST_HEAD(tmp_list);
int ret = 0;
unsigned long flags;
might_sleep();
ASSERT_RTNL();
spin_lock_irqsave(&local->sta_lock, flags);
list_for_each_entry_safe(sta, tmp, &local->sta_list, list) {
if (!sdata || sdata == sta->sdata) {
__sta_info_unlink(&sta);
if (sta) {
list_add_tail(&sta->list, &tmp_list);
ret++;
}
}
}
spin_unlock_irqrestore(&local->sta_lock, flags);
list_for_each_entry_safe(sta, tmp, &tmp_list, list)
sta_info_destroy(sta);
return ret;
}
/**
* sta_info_flush_delayed - flush matching STA entries from the STA table
*
* This function unlinks all stations for a given interface and queues
* them for freeing. Note that the workqueue function scheduled here has
* to run before any new keys can be added to the system to avoid set_key()
* callback ordering issues.
*
* @sdata: the interface
*/
void sta_info_flush_delayed(struct ieee80211_sub_if_data *sdata)
{
struct ieee80211_local *local = sdata->local;
struct sta_info *sta, *tmp;
unsigned long flags;
bool work = false;
spin_lock_irqsave(&local->sta_lock, flags);
list_for_each_entry_safe(sta, tmp, &local->sta_list, list) {
if (sdata == sta->sdata) {
__sta_info_unlink(&sta);
if (sta) {
list_add_tail(&sta->list,
&local->sta_flush_list);
work = true;
}
}
}
if (work)
schedule_work(&local->sta_flush_work);
spin_unlock_irqrestore(&local->sta_lock, flags);
}