linux/net/mac80211/sta_info.c
Michael Wu be8755e180 [MAC80211]: improve locking of sta_info related structures
The sta_info code has some awkward locking which prevents some driver
callbacks from being allowed to sleep. This patch makes the locking more
focused so code that calls driver callbacks are allowed to sleep. It also
converts sta_lock to a rwlock.

Signed-off-by: Michael Wu <flamingice@sourmilk.net>
Signed-off-by: Jiri Benc <jbenc@suse.cz>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2007-10-10 16:47:37 -07:00

435 lines
10 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 <net/mac80211.h>
#include "ieee80211_i.h"
#include "ieee80211_rate.h"
#include "sta_info.h"
#include "debugfs_key.h"
#include "debugfs_sta.h"
/* 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)];
local->sta_hash[STA_HASH(sta->addr)] = sta;
}
/* 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) {
local->sta_hash[STA_HASH(sta->addr)] = s->hnext;
return 0;
}
while (s->hnext && s->hnext != sta)
s = s->hnext;
if (s->hnext) {
s->hnext = sta->hnext;
return 0;
}
return -ENOENT;
}
struct sta_info *sta_info_get(struct ieee80211_local *local, u8 *addr)
{
struct sta_info *sta;
read_lock_bh(&local->sta_lock);
sta = local->sta_hash[STA_HASH(addr)];
while (sta) {
if (memcmp(sta->addr, addr, ETH_ALEN) == 0) {
__sta_info_get(sta);
break;
}
sta = sta->hnext;
}
read_unlock_bh(&local->sta_lock);
return sta;
}
EXPORT_SYMBOL(sta_info_get);
int sta_info_min_txrate_get(struct ieee80211_local *local)
{
struct sta_info *sta;
struct ieee80211_hw_mode *mode;
int min_txrate = 9999999;
int i;
read_lock_bh(&local->sta_lock);
mode = local->oper_hw_mode;
for (i = 0; i < STA_HASH_SIZE; i++) {
sta = local->sta_hash[i];
while (sta) {
if (sta->txrate < min_txrate)
min_txrate = sta->txrate;
sta = sta->hnext;
}
}
read_unlock_bh(&local->sta_lock);
if (min_txrate == 9999999)
min_txrate = 0;
return mode->rates[min_txrate].rate;
}
static void sta_info_release(struct kref *kref)
{
struct sta_info *sta = container_of(kref, struct sta_info, kref);
struct ieee80211_local *local = sta->local;
struct sk_buff *skb;
/* free sta structure; it has already been removed from
* hash table etc. external structures. Make sure that all
* buffered frames are release (one might have been added
* after sta_info_free() was called). */
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);
}
rate_control_free_sta(sta->rate_ctrl, sta->rate_ctrl_priv);
rate_control_put(sta->rate_ctrl);
if (sta->key)
ieee80211_debugfs_key_sta_del(sta->key, sta);
kfree(sta);
}
void sta_info_put(struct sta_info *sta)
{
kref_put(&sta->kref, sta_info_release);
}
EXPORT_SYMBOL(sta_info_put);
struct sta_info * sta_info_add(struct ieee80211_local *local,
struct net_device *dev, u8 *addr, gfp_t gfp)
{
struct sta_info *sta;
sta = kzalloc(sizeof(*sta), gfp);
if (!sta)
return NULL;
kref_init(&sta->kref);
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;
}
memcpy(sta->addr, addr, ETH_ALEN);
sta->local = local;
sta->dev = dev;
skb_queue_head_init(&sta->ps_tx_buf);
skb_queue_head_init(&sta->tx_filtered);
__sta_info_get(sta); /* sta used by caller, decremented by
* sta_info_put() */
write_lock_bh(&local->sta_lock);
list_add(&sta->list, &local->sta_list);
local->num_sta++;
sta_info_hash_add(local, sta);
if (local->ops->sta_table_notification)
local->ops->sta_table_notification(local_to_hw(local),
local->num_sta);
write_unlock_bh(&local->sta_lock);
sta->key_idx_compression = HW_KEY_IDX_INVALID;
#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
printk(KERN_DEBUG "%s: Added STA " MAC_FMT "\n",
local->mdev->name, MAC_ARG(addr));
#endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
#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. */
queue_work(local->hw.workqueue, &local->sta_debugfs_add);
#endif
return sta;
}
/* Caller must hold local->sta_lock */
void sta_info_remove(struct sta_info *sta)
{
struct ieee80211_local *local = sta->local;
struct ieee80211_sub_if_data *sdata;
/* don't do anything if we've been removed already */
if (sta_info_hash_del(local, sta))
return;
list_del(&sta->list);
sdata = IEEE80211_DEV_TO_SUB_IF(sta->dev);
if (sta->flags & WLAN_STA_PS) {
sta->flags &= ~WLAN_STA_PS;
if (sdata->bss)
atomic_dec(&sdata->bss->num_sta_ps);
}
local->num_sta--;
sta_info_remove_aid_ptr(sta);
if (local->ops->sta_table_notification)
local->ops->sta_table_notification(local_to_hw(local),
local->num_sta);
}
void sta_info_free(struct sta_info *sta)
{
struct sk_buff *skb;
struct ieee80211_local *local = sta->local;
might_sleep();
write_lock_bh(&local->sta_lock);
sta_info_remove(sta);
write_unlock_bh(&local->sta_lock);
while ((skb = skb_dequeue(&sta->ps_tx_buf)) != NULL) {
local->total_ps_buffered--;
dev_kfree_skb(skb);
}
while ((skb = skb_dequeue(&sta->tx_filtered)) != NULL) {
dev_kfree_skb(skb);
}
if (sta->key) {
if (local->ops->set_key) {
struct ieee80211_key_conf *key;
key = ieee80211_key_data2conf(local, sta->key);
if (key) {
local->ops->set_key(local_to_hw(local),
DISABLE_KEY,
sta->addr, key, sta->aid);
kfree(key);
}
}
} else if (sta->key_idx_compression != HW_KEY_IDX_INVALID) {
struct ieee80211_key_conf conf;
memset(&conf, 0, sizeof(conf));
conf.hw_key_idx = sta->key_idx_compression;
conf.alg = ALG_NULL;
conf.flags |= IEEE80211_KEY_FORCE_SW_ENCRYPT;
local->ops->set_key(local_to_hw(local), DISABLE_KEY,
sta->addr, &conf, sta->aid);
sta->key_idx_compression = HW_KEY_IDX_INVALID;
}
#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
printk(KERN_DEBUG "%s: Removed STA " MAC_FMT "\n",
local->mdev->name, MAC_ARG(sta->addr));
#endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
if (sta->key) {
ieee80211_debugfs_key_remove(sta->key);
ieee80211_key_free(sta->key);
sta->key = NULL;
}
rate_control_remove_sta_debugfs(sta);
ieee80211_sta_debugfs_remove(sta);
sta_info_put(sta);
}
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;
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);
if (skb_queue_empty(&sta->ps_tx_buf))
sta->flags &= ~WLAN_STA_TIM;
} else
skb = NULL;
spin_unlock_irqrestore(&sta->ps_tx_buf.lock, flags);
if (skb) {
local->total_ps_buffered--;
printk(KERN_DEBUG "Buffered frame expired (STA "
MAC_FMT ")\n", MAC_ARG(sta->addr));
dev_kfree_skb(skb);
} else
break;
}
}
static void sta_info_cleanup(unsigned long data)
{
struct ieee80211_local *local = (struct ieee80211_local *) data;
struct sta_info *sta;
read_lock_bh(&local->sta_lock);
list_for_each_entry(sta, &local->sta_list, list) {
__sta_info_get(sta);
sta_info_cleanup_expire_buffered(local, sta);
sta_info_put(sta);
}
read_unlock_bh(&local->sta_lock);
local->sta_cleanup.expires = jiffies + STA_INFO_CLEANUP_INTERVAL;
add_timer(&local->sta_cleanup);
}
#ifdef CONFIG_MAC80211_DEBUGFS
static void sta_info_debugfs_add_task(struct work_struct *work)
{
struct ieee80211_local *local =
container_of(work, struct ieee80211_local, sta_debugfs_add);
struct sta_info *sta, *tmp;
while (1) {
sta = NULL;
read_lock_bh(&local->sta_lock);
list_for_each_entry(tmp, &local->sta_list, list) {
if (!tmp->debugfs.dir) {
sta = tmp;
__sta_info_get(sta);
break;
}
}
read_unlock_bh(&local->sta_lock);
if (!sta)
break;
ieee80211_sta_debugfs_add(sta);
rate_control_add_sta_debugfs(sta);
sta_info_put(sta);
}
}
#endif
void sta_info_init(struct ieee80211_local *local)
{
rwlock_init(&local->sta_lock);
INIT_LIST_HEAD(&local->sta_list);
init_timer(&local->sta_cleanup);
local->sta_cleanup.expires = jiffies + STA_INFO_CLEANUP_INTERVAL;
local->sta_cleanup.data = (unsigned long) local;
local->sta_cleanup.function = sta_info_cleanup;
#ifdef CONFIG_MAC80211_DEBUGFS
INIT_WORK(&local->sta_debugfs_add, sta_info_debugfs_add_task);
#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);
sta_info_flush(local, NULL);
}
void sta_info_remove_aid_ptr(struct sta_info *sta)
{
struct ieee80211_sub_if_data *sdata;
if (sta->aid <= 0)
return;
sdata = IEEE80211_DEV_TO_SUB_IF(sta->dev);
if (sdata->local->ops->set_tim)
sdata->local->ops->set_tim(local_to_hw(sdata->local),
sta->aid, 0);
if (sdata->bss)
__bss_tim_clear(sdata->bss, sta->aid);
}
/**
* sta_info_flush - flush matching STA entries from the STA table
* @local: local interface data
* @dev: matching rule for the net device (sta->dev) or %NULL to match all STAs
*/
void sta_info_flush(struct ieee80211_local *local, struct net_device *dev)
{
struct sta_info *sta, *tmp;
LIST_HEAD(tmp_list);
write_lock_bh(&local->sta_lock);
list_for_each_entry_safe(sta, tmp, &local->sta_list, list)
if (!dev || dev == sta->dev) {
__sta_info_get(sta);
sta_info_remove(sta);
list_add_tail(&sta->list, &tmp_list);
}
write_unlock_bh(&local->sta_lock);
list_for_each_entry_safe(sta, tmp, &tmp_list, list) {
sta_info_free(sta);
sta_info_put(sta);
}
}