Commit 34e89507 authored by Johannes Berg's avatar Johannes Berg Committed by John W. Linville

mac80211: allow station add/remove to sleep

Many drivers would like to sleep during station
addition and removal, and currently have a high
complexity there from not being able to.

This introduces two new callbacks sta_add() and
sta_remove() that drivers can implement instead
of using sta_notify() and that can sleep, and
the new sta_add() callback is also allowed to
fail.

The reason we didn't do this previously is that
the IBSS code wants to insert stations from the
RX path, which is a tasklet, so cannot sleep.
This patch will keep the station allocation in
that path, but moves adding the station to the
driver out of line. Since the addition can now
fail, we can have IBSS peer structs the driver
rejected -- in that case we still talk to the
station but never tell the driver about it in
the control.sta pointer. If there will ever be
a driver that has a low limit on the number of
stations and that cannot talk to any stations
that are not known to it, we need to do come up
with a new strategy of handling larger IBSSs,
maybe quicker expiry or rejecting peers.
Signed-off-by: default avatarJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent 070bb547
......@@ -814,7 +814,7 @@ enum set_key_cmd {
* mac80211, any ieee80211_sta pointer you get access to must
* either be protected by rcu_read_lock() explicitly or implicitly,
* or you must take good care to not use such a pointer after a
* call to your sta_notify callback that removed it.
* call to your sta_remove callback that removed it.
*
* @addr: MAC address
* @aid: AID we assigned to the station if we're an AP
......@@ -840,8 +840,8 @@ struct ieee80211_sta {
* indicates addition and removal of a station to station table,
* or if a associated station made a power state transition.
*
* @STA_NOTIFY_ADD: a station was added to the station table
* @STA_NOTIFY_REMOVE: a station being removed from the station table
* @STA_NOTIFY_ADD: (DEPRECATED) a station was added to the station table
* @STA_NOTIFY_REMOVE: (DEPRECATED) a station being removed from the station table
* @STA_NOTIFY_SLEEP: a station is now sleeping
* @STA_NOTIFY_AWAKE: a sleeping station woke up
*/
......@@ -1534,9 +1534,14 @@ enum ieee80211_ampdu_mlme_action {
* @set_rts_threshold: Configuration of RTS threshold (if device needs it)
* The callback can sleep.
*
* @sta_notify: Notifies low level driver about addition, removal or power
* state transition of an associated station, AP, IBSS/WDS/mesh peer etc.
* Must be atomic.
* @sta_add: Notifies low level driver about addition of an associated station,
* AP, IBSS/WDS/mesh peer etc. This callback can sleep.
*
* @sta_remove: Notifies low level driver about removal of an associated
* station, AP, IBSS/WDS/mesh peer etc. This callback can sleep.
*
* @sta_notify: Notifies low level driver about power state transition of an
* associated station, AP, IBSS/WDS/mesh peer etc. Must be atomic.
*
* @conf_tx: Configure TX queue parameters (EDCF (aifs, cw_min, cw_max),
* bursting) for a hardware TX queue.
......@@ -1635,6 +1640,10 @@ struct ieee80211_ops {
void (*get_tkip_seq)(struct ieee80211_hw *hw, u8 hw_key_idx,
u32 *iv32, u16 *iv16);
int (*set_rts_threshold)(struct ieee80211_hw *hw, u32 value);
int (*sta_add)(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
struct ieee80211_sta *sta);
int (*sta_remove)(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
struct ieee80211_sta *sta);
void (*sta_notify)(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
enum sta_notify_cmd, struct ieee80211_sta *sta);
int (*conf_tx)(struct ieee80211_hw *hw, u16 queue,
......
......@@ -747,9 +747,7 @@ static int ieee80211_add_station(struct wiphy *wiphy, struct net_device *dev,
layer2_update = sdata->vif.type == NL80211_IFTYPE_AP_VLAN ||
sdata->vif.type == NL80211_IFTYPE_AP;
rcu_read_lock();
err = sta_info_insert(sta);
err = sta_info_insert_rcu(sta);
if (err) {
rcu_read_unlock();
return err;
......@@ -768,26 +766,13 @@ static int ieee80211_del_station(struct wiphy *wiphy, struct net_device *dev,
{
struct ieee80211_local *local = wiphy_priv(wiphy);
struct ieee80211_sub_if_data *sdata;
struct sta_info *sta;
sdata = IEEE80211_DEV_TO_SUB_IF(dev);
if (mac) {
rcu_read_lock();
sta = sta_info_get_bss(sdata, mac);
if (!sta) {
rcu_read_unlock();
return -ENOENT;
}
sta_info_unlink(&sta);
rcu_read_unlock();
sta_info_destroy(sta);
} else
sta_info_flush(local, sdata);
if (mac)
return sta_info_destroy_addr_bss(sdata, mac);
sta_info_flush(local, sdata);
return 0;
}
......
......@@ -243,6 +243,40 @@ static inline void drv_sta_notify(struct ieee80211_local *local,
trace_drv_sta_notify(local, sdata, cmd, sta);
}
static inline int drv_sta_add(struct ieee80211_local *local,
struct ieee80211_sub_if_data *sdata,
struct ieee80211_sta *sta)
{
int ret = 0;
might_sleep();
if (local->ops->sta_add)
ret = local->ops->sta_add(&local->hw, &sdata->vif, sta);
else if (local->ops->sta_notify)
local->ops->sta_notify(&local->hw, &sdata->vif,
STA_NOTIFY_ADD, sta);
trace_drv_sta_add(local, sdata, sta, ret);
return ret;
}
static inline void drv_sta_remove(struct ieee80211_local *local,
struct ieee80211_sub_if_data *sdata,
struct ieee80211_sta *sta)
{
might_sleep();
if (local->ops->sta_remove)
local->ops->sta_remove(&local->hw, &sdata->vif, sta);
else if (local->ops->sta_notify)
local->ops->sta_notify(&local->hw, &sdata->vif,
STA_NOTIFY_REMOVE, sta);
trace_drv_sta_remove(local, sdata, sta);
}
static inline int drv_conf_tx(struct ieee80211_local *local, u16 queue,
const struct ieee80211_tx_queue_params *params)
{
......
......@@ -545,6 +545,58 @@ TRACE_EVENT(drv_sta_notify,
)
);
TRACE_EVENT(drv_sta_add,
TP_PROTO(struct ieee80211_local *local,
struct ieee80211_sub_if_data *sdata,
struct ieee80211_sta *sta, int ret),
TP_ARGS(local, sdata, sta, ret),
TP_STRUCT__entry(
LOCAL_ENTRY
VIF_ENTRY
STA_ENTRY
__field(int, ret)
),
TP_fast_assign(
LOCAL_ASSIGN;
VIF_ASSIGN;
STA_ASSIGN;
__entry->ret = ret;
),
TP_printk(
LOCAL_PR_FMT VIF_PR_FMT STA_PR_FMT " ret:%d",
LOCAL_PR_ARG, VIF_PR_ARG, STA_PR_ARG, __entry->ret
)
);
TRACE_EVENT(drv_sta_remove,
TP_PROTO(struct ieee80211_local *local,
struct ieee80211_sub_if_data *sdata,
struct ieee80211_sta *sta),
TP_ARGS(local, sdata, sta),
TP_STRUCT__entry(
LOCAL_ENTRY
VIF_ENTRY
STA_ENTRY
),
TP_fast_assign(
LOCAL_ASSIGN;
VIF_ASSIGN;
STA_ASSIGN;
),
TP_printk(
LOCAL_PR_FMT VIF_PR_FMT STA_PR_FMT,
LOCAL_PR_ARG, VIF_PR_ARG, STA_PR_ARG
)
);
TRACE_EVENT(drv_conf_tx,
TP_PROTO(struct ieee80211_local *local, u16 queue,
const struct ieee80211_tx_queue_params *params,
......
......@@ -275,10 +275,12 @@ static void ieee80211_rx_bss_info(struct ieee80211_sub_if_data *sdata,
(unsigned long long) supp_rates,
(unsigned long long) sta->sta.supp_rates[band]);
#endif
} else
ieee80211_ibss_add_sta(sdata, mgmt->bssid, mgmt->sa, supp_rates);
rcu_read_unlock();
rcu_read_unlock();
} else {
rcu_read_unlock();
ieee80211_ibss_add_sta(sdata, mgmt->bssid, mgmt->sa,
supp_rates, GFP_KERNEL);
}
}
bss = ieee80211_bss_info_update(local, rx_status, mgmt, len, elems,
......@@ -368,7 +370,8 @@ static void ieee80211_rx_bss_info(struct ieee80211_sub_if_data *sdata,
sdata->name, mgmt->bssid);
#endif
ieee80211_sta_join_ibss(sdata, bss);
ieee80211_ibss_add_sta(sdata, mgmt->bssid, mgmt->sa, supp_rates);
ieee80211_ibss_add_sta(sdata, mgmt->bssid, mgmt->sa,
supp_rates, GFP_KERNEL);
}
put_bss:
......@@ -381,7 +384,8 @@ static void ieee80211_rx_bss_info(struct ieee80211_sub_if_data *sdata,
* must be callable in atomic context.
*/
struct sta_info *ieee80211_ibss_add_sta(struct ieee80211_sub_if_data *sdata,
u8 *bssid,u8 *addr, u32 supp_rates)
u8 *bssid,u8 *addr, u32 supp_rates,
gfp_t gfp)
{
struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
struct ieee80211_local *local = sdata->local;
......@@ -410,7 +414,7 @@ struct sta_info *ieee80211_ibss_add_sta(struct ieee80211_sub_if_data *sdata,
wiphy_name(local->hw.wiphy), addr, sdata->name);
#endif
sta = sta_info_alloc(sdata, addr, GFP_ATOMIC);
sta = sta_info_alloc(sdata, addr, gfp);
if (!sta)
return NULL;
......@@ -422,9 +426,9 @@ struct sta_info *ieee80211_ibss_add_sta(struct ieee80211_sub_if_data *sdata,
rate_control_rate_init(sta);
/* If it fails, maybe we raced another insertion? */
if (sta_info_insert(sta))
return NULL;
return sta_info_get(sdata, addr);
return sta;
}
......
......@@ -688,15 +688,18 @@ struct ieee80211_local {
/* Station data */
/*
* The lock only protects the list, hash, timer and counter
* against manipulation, reads are done in RCU. Additionally,
* the lock protects each BSS's TIM bitmap.
* The mutex only protects the list and counter,
* reads are done in RCU.
* Additionally, the lock protects the hash table,
* the pending list and each BSS's TIM bitmap.
*/
struct mutex sta_mtx;
spinlock_t sta_lock;
unsigned long num_sta;
struct list_head sta_list;
struct list_head sta_list, sta_pending_list;
struct sta_info *sta_hash[STA_HASH_SIZE];
struct timer_list sta_cleanup;
struct work_struct sta_finish_work;
int sta_generation;
struct sk_buff_head pending[IEEE80211_MAX_QUEUES];
......@@ -770,10 +773,6 @@ struct ieee80211_local {
assoc_led_name[32], radio_led_name[32];
#endif
#ifdef CONFIG_MAC80211_DEBUGFS
struct work_struct sta_debugfs_add;
#endif
#ifdef CONFIG_MAC80211_DEBUG_COUNTERS
/* TX/RX handler statistics */
unsigned int tx_handlers_drop;
......@@ -985,7 +984,8 @@ void ieee80211_ibss_setup_sdata(struct ieee80211_sub_if_data *sdata);
ieee80211_rx_result
ieee80211_ibss_rx_mgmt(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb);
struct sta_info *ieee80211_ibss_add_sta(struct ieee80211_sub_if_data *sdata,
u8 *bssid, u8 *addr, u32 supp_rates);
u8 *bssid, u8 *addr, u32 supp_rates,
gfp_t gfp);
int ieee80211_ibss_join(struct ieee80211_sub_if_data *sdata,
struct cfg80211_ibss_params *params);
int ieee80211_ibss_leave(struct ieee80211_sub_if_data *sdata);
......
......@@ -102,7 +102,7 @@ static struct sta_info *mesh_plink_alloc(struct ieee80211_sub_if_data *sdata,
if (local->num_sta >= MESH_MAX_PLINKS)
return NULL;
sta = sta_info_alloc(sdata, hw_addr, GFP_ATOMIC);
sta = sta_info_alloc(sdata, hw_addr, GFP_KERNEL);
if (!sta)
return NULL;
......@@ -236,12 +236,12 @@ void mesh_neighbour_update(u8 *hw_addr, u32 rates, struct ieee80211_sub_if_data
sta = sta_info_get(sdata, hw_addr);
if (!sta) {
rcu_read_unlock();
sta = mesh_plink_alloc(sdata, hw_addr, rates);
if (!sta) {
rcu_read_unlock();
if (!sta)
return;
}
if (sta_info_insert(sta)) {
if (sta_info_insert_rcu(sta)) {
rcu_read_unlock();
return;
}
......@@ -485,9 +485,11 @@ void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata, struct ieee80211_m
} else if (!sta) {
/* ftype == PLINK_OPEN */
u32 rates;
rcu_read_unlock();
if (!mesh_plink_free_count(sdata)) {
mpl_dbg("Mesh plink error: no more free plinks\n");
rcu_read_unlock();
return;
}
......@@ -495,10 +497,9 @@ void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata, struct ieee80211_m
sta = mesh_plink_alloc(sdata, mgmt->sa, rates);
if (!sta) {
mpl_dbg("Mesh plink error: plink table full\n");
rcu_read_unlock();
return;
}
if (sta_info_insert(sta)) {
if (sta_info_insert_rcu(sta)) {
rcu_read_unlock();
return;
}
......
......@@ -822,19 +822,7 @@ static void ieee80211_set_disassoc(struct ieee80211_sub_if_data *sdata)
changed |= BSS_CHANGED_BSSID;
ieee80211_bss_info_change_notify(sdata, changed);
rcu_read_lock();
sta = sta_info_get(sdata, bssid);
if (!sta) {
rcu_read_unlock();
return;
}
sta_info_unlink(&sta);
rcu_read_unlock();
sta_info_destroy(sta);
sta_info_destroy_addr(sdata, bssid);
}
void ieee80211_sta_rx_notify(struct ieee80211_sub_if_data *sdata,
......
......@@ -11,7 +11,6 @@ int __ieee80211_suspend(struct ieee80211_hw *hw)
struct ieee80211_local *local = hw_to_local(hw);
struct ieee80211_sub_if_data *sdata;
struct sta_info *sta;
unsigned long flags;
ieee80211_scan_cancel(local);
......@@ -55,22 +54,21 @@ int __ieee80211_suspend(struct ieee80211_hw *hw)
rcu_read_unlock();
/* remove STAs */
spin_lock_irqsave(&local->sta_lock, flags);
mutex_lock(&local->sta_mtx);
list_for_each_entry(sta, &local->sta_list, list) {
if (local->ops->sta_notify) {
if (sta->uploaded) {
sdata = sta->sdata;
if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
sdata = container_of(sdata->bss,
struct ieee80211_sub_if_data,
u.ap);
drv_sta_notify(local, sdata, STA_NOTIFY_REMOVE,
&sta->sta);
drv_sta_remove(local, sdata, &sta->sta);
}
mesh_plink_quiesce(sta);
}
spin_unlock_irqrestore(&local->sta_lock, flags);
mutex_unlock(&local->sta_mtx);
/* remove all interfaces */
list_for_each_entry(sdata, &local->interfaces, list) {
......
......@@ -2244,8 +2244,8 @@ static int prepare_for_handlers(struct ieee80211_sub_if_data *sdata,
rate_idx = 0; /* TODO: HT rates */
else
rate_idx = status->rate_idx;
rx->sta = ieee80211_ibss_add_sta(sdata, bssid, hdr->addr2,
BIT(rate_idx));
rx->sta = ieee80211_ibss_add_sta(sdata, bssid,
hdr->addr2, BIT(rate_idx), GFP_ATOMIC);
}
break;
case NL80211_IFTYPE_MESH_POINT:
......
......@@ -32,49 +32,33 @@
* 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.
* 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()!
*
* sta entries are added by mac80211 when you establish a link with a
* 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 assocation response from the AP. For IBSS this occurs when
* we receive a probe response or a beacon from target IBSS network. For
* WDS we add the sta for the peer imediately upon device open. When using
* AP mode we add stations for each respective station upon request from
* userspace through nl80211.
* get to know about a peer on the same IBSS. For WDS we add the sta for
* the peer imediately upon device open. When using AP mode we add stations
* for each respective station upon request from userspace through nl80211.
*
* 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, various sta_info_destroy_*()
* calls are available.
*
* 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.
* 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 */
......@@ -185,101 +169,6 @@ static void __sta_info_free(struct ieee80211_local *local,
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;
cancel_work_sync(&sta->drv_unblock_wk);
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++) {
struct tid_ampdu_rx *tid_rx;
struct tid_ampdu_tx *tid_tx;
spin_lock_bh(&sta->lock);
tid_rx = sta->ampdu_mlme.tid_rx[i];
/* Make sure timer won't free the tid_rx struct, see below */
if (tid_rx)
tid_rx->shutdown = true;
spin_unlock_bh(&sta->lock);
/*
* Outside spinlock - shutdown is true now so that the timer
* won't free tid_rx, we have to do that now. Can't let the
* timer do it because we have to sync the timer outside the
* lock that it takes itself.
*/
if (tid_rx) {
del_timer_sync(&tid_rx->session_timer);
kfree(tid_rx);
}
/*
* No need to do such complications for TX agg sessions, the
* path leading to freeing the tid_tx struct goes via a call
* from the driver, and thus needs to look up the sta struct
* again, which cannot be found when we get here. Hence, we
* just need to delete the timer and free the aggregation
* info; we won't be telling the peer about it then but that
* doesn't matter if we're not talking to it again anyway.
*/
tid_tx = sta->ampdu_mlme.tid_tx[i];
if (tid_tx) {
del_timer_sync(&tid_tx->addba_resp_timer);
/*
* STA removed while aggregation session being
* started? Bit odd, but purge frames anyway.
*/
skb_queue_purge(&tid_tx->pending);
kfree(tid_tx);
}
}
__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)
......@@ -376,7 +265,7 @@ struct sta_info *sta_info_alloc(struct ieee80211_sub_if_data *sdata,
return sta;
}
int sta_info_insert(struct sta_info *sta)
static int sta_info_finish_insert(struct sta_info *sta, bool async)
{
struct ieee80211_local *local = sta->local;
struct ieee80211_sub_if_data *sdata = sta->sdata;
......@@ -384,6 +273,91 @@ int sta_info_insert(struct sta_info *sta)
unsigned long flags;
int err = 0;
WARN_ON(!mutex_is_locked(&local->sta_mtx));
/* notify driver */
if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
sdata = container_of(sdata->bss,
struct ieee80211_sub_if_data,
u.ap);
err = drv_sta_add(local, sdata, &sta->sta);
if (err) {
if (!async)
return err;
printk(KERN_DEBUG "%s: failed to add IBSS STA %pM to driver (%d)"
" - keeping it anyway.\n",
sdata->name, sta->sta.addr, err);
} else {
sta->uploaded = true;
#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
if (async)
printk(KERN_DEBUG "%s: Finished adding IBSS STA %pM\n",
wiphy_name(local->hw.wiphy), sta->sta.addr);
#endif
}
sdata = sta->sdata;
if (!async) {
local->num_sta++;
local->sta_generation++;
smp_mb();
/* make the station visible */
spin_lock_irqsave(&local->sta_lock, flags);
sta_info_hash_add(local, sta);
spin_unlock_irqrestore(&local->sta_lock, flags);