@@ -723,13 +723,7 @@ struct ieee80211_local {
struct sk_buff_head pending[IEEE80211_MAX_QUEUES];
struct tasklet_struct tx_pending_tasklet;
- /*
- * This lock is used to prevent concurrent A-MPDU
- * session start/stop processing, this thus also
- * synchronises the ->ampdu_action() callback to
- * drivers and limits it to one at a time.
- */
- spinlock_t ampdu_lock;
+ atomic_t agg_queue_stop[IEEE80211_MAX_QUEUES];
/* number of interfaces with corresponding IFF_ flags */
atomic_t iff_allmultis, iff_promiscs;
@@ -460,8 +460,10 @@ struct ieee80211_hw *ieee80211_alloc_hw(
sta_info_init(local);
- for (i = 0; i < IEEE80211_MAX_QUEUES; i++)
+ for (i = 0; i < IEEE80211_MAX_QUEUES; i++) {
skb_queue_head_init(&local->pending[i]);
+ atomic_set(&local->agg_queue_stop[i], 0);
+ }
tasklet_init(&local->tx_pending_tasklet, ieee80211_tx_pending,
(unsigned long)local);
@@ -472,8 +474,6 @@ struct ieee80211_hw *ieee80211_alloc_hw(
skb_queue_head_init(&local->skb_queue);
skb_queue_head_init(&local->skb_queue_unreliable);
- spin_lock_init(&local->ampdu_lock);
-
return local_to_hw(local);
}
EXPORT_SYMBOL(ieee80211_alloc_hw);
@@ -220,6 +220,41 @@ static inline int ieee80211_ac_from_tid(
return ieee802_1d_to_ac[tid & 7];
}
+/*
+ * When multiple aggregation sessions on multiple stations
+ * are being created/destroyed simultaneously, we need to
+ * refcount the global queue stop caused by that in order
+ * to not get into a situation where one of the aggregation
+ * setup or teardown re-enables queues before the other is
+ * ready to handle that.
+ *
+ * These two functions take care of this issue by keeping
+ * a global "agg_queue_stop" refcount.
+ */
+static void __acquires(agg_queue)
+ieee80211_stop_queue_agg(struct ieee80211_local *local, int tid)
+{
+ int queue = ieee80211_ac_from_tid(tid);
+
+ if (atomic_inc_return(&local->agg_queue_stop[queue]) == 1)
+ ieee80211_stop_queue_by_reason(
+ &local->hw, queue,
+ IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
+ __acquire(agg_queue);
+}
+
+static void __releases(agg_queue)
+ieee80211_wake_queue_agg(struct ieee80211_local *local, int tid)
+{
+ int queue = ieee80211_ac_from_tid(tid);
+
+ if (atomic_dec_return(&local->agg_queue_stop[queue]) == 0)
+ ieee80211_wake_queue_by_reason(
+ &local->hw, queue,
+ IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
+ __release(agg_queue);
+}
+
int ieee80211_start_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid)
{
struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
@@ -263,7 +298,6 @@ int ieee80211_start_tx_ba_session(struct
}
spin_lock_bh(&sta->lock);
- spin_lock(&local->ampdu_lock);
/* we have tried too many times, receiver does not want A-MPDU */
if (sta->ampdu_mlme.addba_req_num[tid] > HT_AGG_MAX_RETRIES) {
@@ -289,9 +323,7 @@ int ieee80211_start_tx_ba_session(struct
* which would require us to put them to the AC pending
* afterwards which just makes the code more complex.
*/
- ieee80211_stop_queue_by_reason(
- &local->hw, ieee80211_ac_from_tid(tid),
- IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
+ ieee80211_stop_queue_agg(local, tid);
/* prepare A-MPDU MLME for Tx aggregation */
tid_tx = kzalloc(sizeof(struct tid_ampdu_tx), GFP_ATOMIC);
@@ -327,11 +359,7 @@ int ieee80211_start_tx_ba_session(struct
rcu_assign_pointer(sta->ampdu_mlme.tid_tx[tid], tid_tx);
/* Driver vetoed or OKed, but we can take packets again now */
- ieee80211_wake_queue_by_reason(
- &local->hw, ieee80211_ac_from_tid(tid),
- IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
-
- spin_unlock(&local->ampdu_lock);
+ ieee80211_wake_queue_agg(local, tid);
/* activate the timer for the recipient's addBA response */
tid_tx->addba_resp_timer.expires = jiffies + ADDBA_RESP_INTERVAL;
@@ -358,11 +386,8 @@ int ieee80211_start_tx_ba_session(struct
err_free:
kfree(tid_tx);
err_wake_queue:
- ieee80211_wake_queue_by_reason(
- &local->hw, ieee80211_ac_from_tid(tid),
- IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
+ ieee80211_wake_queue_agg(local, tid);
err_unlock_sta:
- spin_unlock(&local->ampdu_lock);
spin_unlock_bh(&sta->lock);
return ret;
}
@@ -370,19 +395,16 @@ EXPORT_SYMBOL(ieee80211_start_tx_ba_sess
/*
* splice packets from the STA's pending to the local pending,
- * requires a call to ieee80211_agg_splice_finish and holding
- * local->ampdu_lock across both calls.
+ * requires a call to ieee80211_agg_splice_finish later
*/
-static void ieee80211_agg_splice_packets(struct ieee80211_local *local,
- struct tid_ampdu_tx *tid_tx,
- u16 tid)
+static void __acquires(agg_queue)
+ieee80211_agg_splice_packets(struct ieee80211_local *local,
+ struct tid_ampdu_tx *tid_tx, u16 tid)
{
+ int queue = ieee80211_ac_from_tid(tid);
unsigned long flags;
- u16 queue = ieee80211_ac_from_tid(tid);
- ieee80211_stop_queue_by_reason(
- &local->hw, queue,
- IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
+ ieee80211_stop_queue_agg(local, tid);
if (WARN(!tid_tx, "TID %d gone but expected when splicing aggregates"
" from the pending queue\n", tid))
@@ -397,11 +419,10 @@ static void ieee80211_agg_splice_packets
}
}
-static void ieee80211_agg_splice_finish(struct ieee80211_local *local, u16 tid)
+static void __releases(agg_queue)
+ieee80211_agg_splice_finish(struct ieee80211_local *local, u16 tid)
{
- ieee80211_wake_queue_by_reason(
- &local->hw, ieee80211_ac_from_tid(tid),
- IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
+ ieee80211_wake_queue_agg(local, tid);
}
/* caller must hold sta->lock */
@@ -414,7 +435,6 @@ static void ieee80211_agg_tx_operational
printk(KERN_DEBUG "Aggregation is on for tid %d\n", tid);
#endif
- spin_lock(&local->ampdu_lock);
ieee80211_agg_splice_packets(local, sta->ampdu_mlme.tid_tx[tid], tid);
/*
* Now mark as operational. This will be visible
@@ -423,7 +443,6 @@ static void ieee80211_agg_tx_operational
*/
set_bit(HT_AGG_STATE_OPERATIONAL, &sta->ampdu_mlme.tid_tx[tid]->state);
ieee80211_agg_splice_finish(local, tid);
- spin_unlock(&local->ampdu_lock);
drv_ampdu_action(local, sta->sdata,
IEEE80211_AMPDU_TX_OPERATIONAL,
@@ -604,7 +623,6 @@ void ieee80211_stop_tx_ba_cb(struct ieee
* more.
*/
- spin_lock(&local->ampdu_lock);
ieee80211_agg_splice_packets(local, tid_tx, tid);
/* future packets must not find the tid_tx struct any more */
@@ -613,7 +631,6 @@ void ieee80211_stop_tx_ba_cb(struct ieee
ieee80211_agg_splice_finish(local, tid);
call_rcu(&tid_tx->rcu_head, kfree_tid_tx);
- spin_unlock(&local->ampdu_lock);
spin_unlock_bh(&sta->lock);
rcu_read_unlock();