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-rw-r--r--net/mac80211/sta_info.c387
1 files changed, 240 insertions, 147 deletions
diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index 81c4e3392f40..ee5b66abc0f1 100644
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -15,6 +15,7 @@
#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"
@@ -23,14 +24,43 @@
#include "debugfs_sta.h"
#include "mesh.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;
-}
-
+/**
+ * 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.
+ *
+ * STA info structures are always "alive" when they are added with
+ * @sta_info_add() [this may be changed in the future to allow allocating
+ * outside of a critical section!], they are then added to the hash
+ * table and list. Therefore, @sta_info_add() must also be RCU protected,
+ * also, the caller of @sta_info_add() cannot assume that it owns the
+ * structure.
+ *
+ * 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.
+ *
+ * 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 wait for an RCU synchronisation before it can be freed. 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(), not before RCU synchronisation, of
+ * course. Note that sta_info_destroy() must be protected by the RTNL.
+ *
+ * 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,
@@ -42,46 +72,39 @@ static int sta_info_hash_del(struct ieee80211_local *local,
if (!s)
return -ENOENT;
if (s == sta) {
- local->sta_hash[STA_HASH(sta->addr)] = s->hnext;
+ 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) {
- s->hnext = sta->hnext;
+ rcu_assign_pointer(s->hnext, sta->hnext);
return 0;
}
return -ENOENT;
}
-/* must hold local->sta_lock */
+/* protected by RCU */
static struct sta_info *__sta_info_find(struct ieee80211_local *local,
u8 *addr)
{
struct sta_info *sta;
- sta = local->sta_hash[STA_HASH(addr)];
+ sta = rcu_dereference(local->sta_hash[STA_HASH(addr)]);
while (sta) {
if (compare_ether_addr(sta->addr, addr) == 0)
break;
- sta = sta->hnext;
+ sta = rcu_dereference(sta->hnext);
}
return sta;
}
struct sta_info *sta_info_get(struct ieee80211_local *local, u8 *addr)
{
- struct sta_info *sta;
-
- read_lock_bh(&local->sta_lock);
- sta = __sta_info_find(local, addr);
- if (sta)
- __sta_info_get(sta);
- read_unlock_bh(&local->sta_lock);
-
- return sta;
+ return __sta_info_find(local, addr);
}
EXPORT_SYMBOL(sta_info_get);
@@ -91,81 +114,101 @@ struct sta_info *sta_info_get_by_idx(struct ieee80211_local *local, int idx,
struct sta_info *sta;
int i = 0;
- read_lock_bh(&local->sta_lock);
- list_for_each_entry(sta, &local->sta_list, list) {
+ list_for_each_entry_rcu(sta, &local->sta_list, list) {
if (i < idx) {
++i;
continue;
- } else if (!dev || dev == sta->dev) {
- __sta_info_get(sta);
- read_unlock_bh(&local->sta_lock);
+ } else if (!dev || dev == sta->sdata->dev) {
return sta;
}
}
- read_unlock_bh(&local->sta_lock);
return NULL;
}
-static void sta_info_release(struct kref *kref)
+void sta_info_destroy(struct sta_info *sta)
{
- struct sta_info *sta = container_of(kref, struct sta_info, kref);
struct ieee80211_local *local = sta->local;
struct sk_buff *skb;
int i;
- /* 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). */
+ ASSERT_RTNL();
+ might_sleep();
+
+ 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
+
+ /*
+ * NOTE: This will call synchronize_rcu() internally to
+ * make sure no key references can be in use. We rely on
+ * that here for the mesh code!
+ */
+ ieee80211_key_free(sta->key);
+ WARN_ON(sta->key);
+
+#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) {
+
+ while ((skb = skb_dequeue(&sta->tx_filtered)) != NULL)
dev_kfree_skb_any(skb);
- }
+
for (i = 0; i < STA_TID_NUM; i++) {
del_timer_sync(&sta->ampdu_mlme.tid_rx[i].session_timer);
del_timer_sync(&sta->ampdu_mlme.tid_tx[i].addba_resp_timer);
}
rate_control_free_sta(sta->rate_ctrl, sta->rate_ctrl_priv);
rate_control_put(sta->rate_ctrl);
+
kfree(sta);
}
-void sta_info_put(struct sta_info *sta)
+/* Caller must hold local->sta_lock */
+static void sta_info_hash_add(struct ieee80211_local *local,
+ struct sta_info *sta)
{
- kref_put(&sta->kref, sta_info_release);
+ sta->hnext = local->sta_hash[STA_HASH(sta->addr)];
+ rcu_assign_pointer(local->sta_hash[STA_HASH(sta->addr)], sta);
}
-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_info_add(struct ieee80211_sub_if_data *sdata,
+ u8 *addr)
{
+ struct ieee80211_local *local = sdata->local;
struct sta_info *sta;
int i;
DECLARE_MAC_BUF(mac);
+ unsigned long flags;
- sta = kzalloc(sizeof(*sta), gfp);
+ sta = kzalloc(sizeof(*sta), GFP_ATOMIC);
if (!sta)
return ERR_PTR(-ENOMEM);
- kref_init(&sta->kref);
+ 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);
+ sta->rate_ctrl_priv = rate_control_alloc_sta(sta->rate_ctrl,
+ GFP_ATOMIC);
if (!sta->rate_ctrl_priv) {
rate_control_put(sta->rate_ctrl);
kfree(sta);
return ERR_PTR(-ENOMEM);
}
- memcpy(sta->addr, addr, ETH_ALEN);
- sta->local = local;
- sta->dev = dev;
spin_lock_init(&sta->ampdu_mlme.ampdu_rx);
spin_lock_init(&sta->ampdu_mlme.ampdu_tx);
for (i = 0; i < STA_TID_NUM; i++) {
@@ -190,29 +233,26 @@ struct sta_info *sta_info_add(struct ieee80211_local *local,
}
skb_queue_head_init(&sta->ps_tx_buf);
skb_queue_head_init(&sta->tx_filtered);
- write_lock_bh(&local->sta_lock);
- /* mark sta as used (by caller) */
- __sta_info_get(sta);
+ spin_lock_irqsave(&local->sta_lock, flags);
/* check if STA exists already */
if (__sta_info_find(local, addr)) {
- write_unlock_bh(&local->sta_lock);
- sta_info_put(sta);
+ spin_unlock_irqrestore(&local->sta_lock, flags);
return ERR_PTR(-EEXIST);
}
list_add(&sta->list, &local->sta_list);
local->num_sta++;
sta_info_hash_add(local, sta);
- if (local->ops->sta_notify) {
- struct ieee80211_sub_if_data *sdata;
- sdata = IEEE80211_DEV_TO_SUB_IF(dev);
+ /* 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, addr);
}
- write_unlock_bh(&local->sta_lock);
+
+ spin_unlock_irqrestore(&local->sta_lock, flags);
#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
printk(KERN_DEBUG "%s: Added STA %s\n",
@@ -252,19 +292,20 @@ static void __sta_info_set_tim_bit(struct ieee80211_if_ap *bss,
{
if (bss)
__bss_tim_set(bss, sta->aid);
- if (sta->local->ops->set_tim)
+ 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)
{
- struct ieee80211_sub_if_data *sdata;
-
- sdata = IEEE80211_DEV_TO_SUB_IF(sta->dev);
+ unsigned long flags;
- read_lock_bh(&sta->local->sta_lock);
- __sta_info_set_tim_bit(sdata->bss, sta);
- read_unlock_bh(&sta->local->sta_lock);
+ 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,
@@ -272,93 +313,135 @@ static void __sta_info_clear_tim_bit(struct ieee80211_if_ap *bss,
{
if (bss)
__bss_tim_clear(bss, sta->aid);
- if (sta->local->ops->set_tim)
+ 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)
{
- struct ieee80211_sub_if_data *sdata;
-
- sdata = IEEE80211_DEV_TO_SUB_IF(sta->dev);
+ unsigned long flags;
- read_lock_bh(&sta->local->sta_lock);
- __sta_info_clear_tim_bit(sdata->bss, sta);
- read_unlock_bh(&sta->local->sta_lock);
+ 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);
}
-/* Caller must hold local->sta_lock */
-void sta_info_remove(struct sta_info *sta)
+/*
+ * See comment in __sta_info_unlink,
+ * caller must hold local->sta_lock.
+ */
+static void __sta_info_pin(struct sta_info *sta)
{
- struct ieee80211_local *local = sta->local;
- struct ieee80211_sub_if_data *sdata;
+ WARN_ON(sta->pin_status != STA_INFO_PIN_STAT_NORMAL);
+ sta->pin_status = STA_INFO_PIN_STAT_PINNED;
+}
- /* don't do anything if we've been removed already */
- if (sta_info_hash_del(local, sta))
- return;
+/*
+ * 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;
- 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);
- __sta_info_clear_tim_bit(sdata->bss, sta);
- }
- local->num_sta--;
+ 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);
- if (ieee80211_vif_is_mesh(&sdata->vif))
- mesh_accept_plinks_update(sdata->dev);
+ return ret;
}
-void sta_info_free(struct sta_info *sta)
+static void __sta_info_unlink(struct sta_info **sta)
{
- struct sk_buff *skb;
- struct ieee80211_local *local = sta->local;
- struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(sta->dev);
-
- DECLARE_MAC_BUF(mac);
-
- might_sleep();
+ 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;
+ }
- write_lock_bh(&local->sta_lock);
- sta_info_remove(sta);
- write_unlock_bh(&local->sta_lock);
+ /*
+ * Also 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) 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)
+ * (3) We set the pin_status to DESTROY here when we
+ * find such an item.
+ * (4) 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;
+ }
- if (ieee80211_vif_is_mesh(&sdata->vif))
- mesh_plink_deactivate(sta);
+ list_del(&(*sta)->list);
- 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)->flags & WLAN_STA_PS) {
+ (*sta)->flags &= ~WLAN_STA_PS;
+ if (sdata->bss)
+ atomic_dec(&sdata->bss->num_sta_ps);
+ __sta_info_clear_tim_bit(sdata->bss, *sta);
}
-#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
- printk(KERN_DEBUG "%s: Removed STA %s\n",
- wiphy_name(local->hw.wiphy), print_mac(mac, sta->addr));
-#endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
-
- ieee80211_key_free(sta->key);
- WARN_ON(sta->key);
+ 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);
+ STA_NOTIFY_REMOVE, (*sta)->addr);
}
- rate_control_remove_sta_debugfs(sta);
- ieee80211_sta_debugfs_remove(sta);
+ if (ieee80211_vif_is_mesh(&sdata->vif)) {
+ mesh_accept_plinks_update(sdata);
+#ifdef CONFIG_MAC80211_MESH
+ del_timer(&(*sta)->plink_timer);
+#endif
+ }
- sta_info_put(sta);
+#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 */
}
+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,
@@ -404,7 +487,7 @@ static void sta_info_cleanup_expire_buffered(struct ieee80211_local *local,
if (!skb)
break;
- sdata = IEEE80211_DEV_TO_SUB_IF(sta->dev);
+ sdata = sta->sdata;
local->total_ps_buffered--;
printk(KERN_DEBUG "Buffered frame expired (STA "
"%s)\n", print_mac(mac, sta->addr));
@@ -421,13 +504,10 @@ 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);
+ rcu_read_lock();
+ list_for_each_entry_rcu(sta, &local->sta_list, list)
sta_info_cleanup_expire_buffered(local, sta);
- sta_info_put(sta);
- }
- read_unlock_bh(&local->sta_lock);
+ rcu_read_unlock();
local->sta_cleanup.expires =
round_jiffies(jiffies + STA_INFO_CLEANUP_INTERVAL);
@@ -435,37 +515,45 @@ static void sta_info_cleanup(unsigned long data)
}
#ifdef CONFIG_MAC80211_DEBUGFS
-static void sta_info_debugfs_add_task(struct work_struct *work)
+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;
while (1) {
sta = NULL;
- read_lock_bh(&local->sta_lock);
+
+ spin_lock_irqsave(&local->sta_lock, flags);
list_for_each_entry(tmp, &local->sta_list, list) {
if (!tmp->debugfs.dir) {
sta = tmp;
- __sta_info_get(sta);
+ __sta_info_pin(sta);
break;
}
}
- read_unlock_bh(&local->sta_lock);
+ spin_unlock_irqrestore(&local->sta_lock, flags);
if (!sta)
break;
ieee80211_sta_debugfs_add(sta);
rate_control_add_sta_debugfs(sta);
- sta_info_put(sta);
+
+ sta = __sta_info_unpin(sta);
+
+ if (sta) {
+ synchronize_rcu();
+ sta_info_destroy(sta);
+ }
}
}
#endif
void sta_info_init(struct ieee80211_local *local)
{
- rwlock_init(&local->sta_lock);
+ spin_lock_init(&local->sta_lock);
INIT_LIST_HEAD(&local->sta_list);
setup_timer(&local->sta_cleanup, sta_info_cleanup,
@@ -474,7 +562,7 @@ void sta_info_init(struct ieee80211_local *local)
round_jiffies(jiffies + STA_INFO_CLEANUP_INTERVAL);
#ifdef CONFIG_MAC80211_DEBUGFS
- INIT_WORK(&local->sta_debugfs_add, sta_info_debugfs_add_task);
+ INIT_WORK(&local->sta_debugfs_add, sta_info_debugfs_add_work);
#endif
}
@@ -493,24 +581,29 @@ void sta_info_stop(struct ieee80211_local *local)
/**
* 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
+ * @sdata: 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)
+void sta_info_flush(struct ieee80211_local *local,
+ struct ieee80211_sub_if_data *sdata)
{
struct sta_info *sta, *tmp;
LIST_HEAD(tmp_list);
+ unsigned long flags;
- 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);
+ might_sleep();
- list_for_each_entry_safe(sta, tmp, &tmp_list, list) {
- sta_info_free(sta);
- sta_info_put(sta);
+ 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);
+ }
}
+ spin_unlock_irqrestore(&local->sta_lock, flags);
+
+ synchronize_rcu();
+
+ list_for_each_entry_safe(sta, tmp, &tmp_list, list)
+ sta_info_destroy(sta);
}
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