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>

1 files changed, 19 insertions, 19 deletions

diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index 108c6fc42fe2..6c4b27be35da 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -1241,7 +1241,7 @@ static void ieee80211_sta_process_addba_request(struct net_device *dev,
 
 
         /* examine state machine */
-        spin_lock_bh(&sta->ampdu_mlme.ampdu_rx);
+        spin_lock_bh(&sta->lock);
 
         if (sta->ampdu_mlme.tid_state_rx[tid] != HT_AGG_STATE_IDLE) {
 #ifdef CONFIG_MAC80211_HT_DEBUG
@@ -1308,7 +1308,7 @@ static void ieee80211_sta_process_addba_request(struct net_device *dev,
         tid_agg_rx->stored_mpdu_num = 0;
         status = WLAN_STATUS_SUCCESS;
 end:
-        spin_unlock_bh(&sta->ampdu_mlme.ampdu_rx);
+        spin_unlock_bh(&sta->lock);
 
 end_no_lock:
         ieee80211_send_addba_resp(sta->sdata->dev, sta->addr, tid,
@@ -1340,10 +1340,10 @@ static void ieee80211_sta_process_addba_resp(struct net_device *dev,
 
         state = &sta->ampdu_mlme.tid_state_tx[tid];
 
-        spin_lock_bh(&sta->ampdu_mlme.ampdu_tx);
+        spin_lock_bh(&sta->lock);
 
         if (!(*state & HT_ADDBA_REQUESTED_MSK)) {
-                spin_unlock_bh(&sta->ampdu_mlme.ampdu_tx);
+                spin_unlock_bh(&sta->lock);
                 printk(KERN_DEBUG "state not HT_ADDBA_REQUESTED_MSK:"
                         "%d\n", *state);
                 goto addba_resp_exit;
@@ -1351,7 +1351,7 @@ static void ieee80211_sta_process_addba_resp(struct net_device *dev,
 
         if (mgmt->u.action.u.addba_resp.dialog_token !=
                 sta->ampdu_mlme.tid_tx[tid]->dialog_token) {
-                spin_unlock_bh(&sta->ampdu_mlme.ampdu_tx);
+                spin_unlock_bh(&sta->lock);
 #ifdef CONFIG_MAC80211_HT_DEBUG
                 printk(KERN_DEBUG "wrong addBA response token, tid %d\n", tid);
 #endif /* CONFIG_MAC80211_HT_DEBUG */
@@ -1375,7 +1375,7 @@ static void ieee80211_sta_process_addba_resp(struct net_device *dev,
                         ieee80211_wake_queue(hw, sta->tid_to_tx_q[tid]);
                 }
 
-                spin_unlock_bh(&sta->ampdu_mlme.ampdu_tx);
+                spin_unlock_bh(&sta->lock);
                 printk(KERN_DEBUG "recipient accepted agg: tid %d \n", tid);
         } else {
                 printk(KERN_DEBUG "recipient rejected agg: tid %d \n", tid);
@@ -1383,7 +1383,7 @@ static void ieee80211_sta_process_addba_resp(struct net_device *dev,
                 sta->ampdu_mlme.addba_req_num[tid]++;
                 /* this will allow the state check in stop_BA_session */
                 *state = HT_AGG_STATE_OPERATIONAL;
-                spin_unlock_bh(&sta->ampdu_mlme.ampdu_tx);
+                spin_unlock_bh(&sta->lock);
                 ieee80211_stop_tx_ba_session(hw, sta->addr, tid,
                                              WLAN_BACK_INITIATOR);
         }
@@ -1453,17 +1453,17 @@ void ieee80211_sta_stop_rx_ba_session(struct net_device *dev, u8 *ra, u16 tid,
         }
 
         /* check if TID is in operational state */
-        spin_lock_bh(&sta->ampdu_mlme.ampdu_rx);
+        spin_lock_bh(&sta->lock);
         if (sta->ampdu_mlme.tid_state_rx[tid]
                                 != HT_AGG_STATE_OPERATIONAL) {
-                spin_unlock_bh(&sta->ampdu_mlme.ampdu_rx);
+                spin_unlock_bh(&sta->lock);
                 rcu_read_unlock();
                 return;
         }
         sta->ampdu_mlme.tid_state_rx[tid] =
                 HT_AGG_STATE_REQ_STOP_BA_MSK |
                 (initiator << HT_AGG_STATE_INITIATOR_SHIFT);
-        spin_unlock_bh(&sta->ampdu_mlme.ampdu_rx);
+        spin_unlock_bh(&sta->lock);
 
         /* stop HW Rx aggregation. ampdu_action existence
          * already verified in session init so we add the BUG_ON */
@@ -1540,10 +1540,10 @@ static void ieee80211_sta_process_delba(struct net_device *dev,
                 ieee80211_sta_stop_rx_ba_session(dev, sta->addr, tid,
                                                  WLAN_BACK_INITIATOR, 0);
         else { /* WLAN_BACK_RECIPIENT */
-                spin_lock_bh(&sta->ampdu_mlme.ampdu_tx);
+                spin_lock_bh(&sta->lock);
                 sta->ampdu_mlme.tid_state_tx[tid] =
                                 HT_AGG_STATE_OPERATIONAL;
-                spin_unlock_bh(&sta->ampdu_mlme.ampdu_tx);
+                spin_unlock_bh(&sta->lock);
                 ieee80211_stop_tx_ba_session(&local->hw, sta->addr, tid,
                                              WLAN_BACK_RECIPIENT);
         }
@@ -1580,9 +1580,9 @@ void sta_addba_resp_timer_expired(unsigned long data)
 
         state = &sta->ampdu_mlme.tid_state_tx[tid];
         /* check if the TID waits for addBA response */
-        spin_lock_bh(&sta->ampdu_mlme.ampdu_tx);
+        spin_lock_bh(&sta->lock);
         if (!(*state & HT_ADDBA_REQUESTED_MSK)) {
-                spin_unlock_bh(&sta->ampdu_mlme.ampdu_tx);
+                spin_unlock_bh(&sta->lock);
                 *state = HT_AGG_STATE_IDLE;
                 printk(KERN_DEBUG "timer expired on tid %d but we are not "
                                 "expecting addBA response there", tid);
@@ -1593,7 +1593,7 @@ void sta_addba_resp_timer_expired(unsigned long data)
 
         /* go through the state check in stop_BA_session */
         *state = HT_AGG_STATE_OPERATIONAL;
-        spin_unlock_bh(&sta->ampdu_mlme.ampdu_tx);
+        spin_unlock_bh(&sta->lock);
         ieee80211_stop_tx_ba_session(hw, temp_sta->addr, tid,
                                      WLAN_BACK_INITIATOR);
 
@@ -1984,8 +1984,8 @@ static void ieee80211_rx_mgmt_assoc_resp(struct ieee80211_sub_if_data *sdata,
          *        to between the sta_info_alloc() and sta_info_insert() above.
          */
 
-        sta->flags |= WLAN_STA_AUTH | WLAN_STA_ASSOC | WLAN_STA_ASSOC_AP |
-                      WLAN_STA_AUTHORIZED;
+        set_sta_flags(sta, WLAN_STA_AUTH | WLAN_STA_ASSOC | WLAN_STA_ASSOC_AP |
+                           WLAN_STA_AUTHORIZED);
 
         rates = 0;
         basic_rates = 0;
@@ -2044,7 +2044,7 @@ static void ieee80211_rx_mgmt_assoc_resp(struct ieee80211_sub_if_data *sdata,
         rate_control_rate_init(sta, local);
 
         if (elems.wmm_param) {
-                sta->flags |= WLAN_STA_WME;
+                set_sta_flags(sta, WLAN_STA_WME);
                 rcu_read_unlock();
                 ieee80211_sta_wmm_params(dev, ifsta, elems.wmm_param,
                                          elems.wmm_param_len);
@@ -4237,7 +4237,7 @@ struct sta_info *ieee80211_ibss_add_sta(struct net_device *dev,
         if (!sta)
                 return NULL;
 
-        sta->flags |= WLAN_STA_AUTHORIZED;
+        set_sta_flags(sta, WLAN_STA_AUTHORIZED);
 
         sta->supp_rates[local->hw.conf.channel->band] =
                 sdata->u.sta.supp_rates_bits[local->hw.conf.channel->band];