mac80211: clean up/fix aggregation code

The aggregation code has a number of quirks, like
inventing an unneeded WLAN_BACK_TIMER value and
leaking memory under certain circumstances during
station destruction. Fix these issues by using
the regular aggregation session teardown code and
blocking new aggregation sessions, all before the
station is really destructed.

As a side effect, this gets rid of the long code
block to destroy aggregation safely.

Additionally, rename tid_state_rx which can only
have the values IDLE and OPERATIONAL to
tid_active_rx to make it easier to understand
that there is no bitwise stuff going on on the
RX side -- the TX side remains because it needs
to keep track of the driver and peer states.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 21 insertions, 27 deletions

diff --git a/net/mac80211/agg-rx.c b/net/mac80211/agg-rx.c
index 7d87f446f030..53233ab50f65 100644
--- a/net/mac80211/agg-rx.c
+++ b/net/mac80211/agg-rx.c
@@ -22,19 +22,20 @@ void __ieee80211_stop_rx_ba_session(struct sta_info *sta, u16 tid,
 				    u16 initiator, u16 reason)
 {
 	struct ieee80211_local *local = sta->local;
+	struct tid_ampdu_rx *tid_rx;
 	int i;
 
-	/* check if TID is in operational state */
 	spin_lock_bh(&sta->lock);
-	if (sta->ampdu_mlme.tid_state_rx[tid] != HT_AGG_STATE_OPERATIONAL) {
+
+	/* check if TID is in operational state */
+	if (!sta->ampdu_mlme.tid_active_rx[tid]) {
 		spin_unlock_bh(&sta->lock);
 		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->lock);
+	sta->ampdu_mlme.tid_active_rx[tid] = false;
+
+	tid_rx = sta->ampdu_mlme.tid_rx[tid];
 
 #ifdef CONFIG_MAC80211_HT_DEBUG
 	printk(KERN_DEBUG "Rx BA session stop requested for %pM tid %u\n",
@@ -46,37 +47,30 @@ void __ieee80211_stop_rx_ba_session(struct sta_info *sta, u16 tid,
 		printk(KERN_DEBUG "HW problem - can not stop rx "
 				"aggregation for tid %d\n", tid);
 
-	/* shutdown timer has not expired */
-	if (initiator != WLAN_BACK_TIMER)
-		del_timer_sync(&sta->ampdu_mlme.tid_rx[tid]->session_timer);
-
 	/* check if this is a self generated aggregation halt */
-	if (initiator == WLAN_BACK_RECIPIENT || initiator == WLAN_BACK_TIMER)
+	if (initiator == WLAN_BACK_RECIPIENT)
 		ieee80211_send_delba(sta->sdata, sta->sta.addr,
 				     tid, 0, reason);
 
 	/* free the reordering buffer */
-	for (i = 0; i < sta->ampdu_mlme.tid_rx[tid]->buf_size; i++) {
-		if (sta->ampdu_mlme.tid_rx[tid]->reorder_buf[i]) {
+	for (i = 0; i < tid_rx->buf_size; i++) {
+		if (tid_rx->reorder_buf[i]) {
 			/* release the reordered frames */
-			dev_kfree_skb(sta->ampdu_mlme.tid_rx[tid]->reorder_buf[i]);
-			sta->ampdu_mlme.tid_rx[tid]->stored_mpdu_num--;
-			sta->ampdu_mlme.tid_rx[tid]->reorder_buf[i] = NULL;
+			dev_kfree_skb(tid_rx->reorder_buf[i]);
+			tid_rx->stored_mpdu_num--;
+			tid_rx->reorder_buf[i] = NULL;
 		}
 	}
 
-	spin_lock_bh(&sta->lock);
 	/* free resources */
-	kfree(sta->ampdu_mlme.tid_rx[tid]->reorder_buf);
-	kfree(sta->ampdu_mlme.tid_rx[tid]->reorder_time);
-
-	if (!sta->ampdu_mlme.tid_rx[tid]->shutdown) {
-		kfree(sta->ampdu_mlme.tid_rx[tid]);
-		sta->ampdu_mlme.tid_rx[tid] = NULL;
-	}
+	kfree(tid_rx->reorder_buf);
+	kfree(tid_rx->reorder_time);
+	sta->ampdu_mlme.tid_rx[tid] = NULL;
 
-	sta->ampdu_mlme.tid_state_rx[tid] = HT_AGG_STATE_IDLE;
 	spin_unlock_bh(&sta->lock);
+
+	del_timer_sync(&tid_rx->session_timer);
+	kfree(tid_rx);
 }
 
 /*
@@ -211,7 +205,7 @@ void ieee80211_process_addba_request(struct ieee80211_local *local,
 	/* examine state machine */
 	spin_lock_bh(&sta->lock);
 
-	if (sta->ampdu_mlme.tid_state_rx[tid] != HT_AGG_STATE_IDLE) {
+	if (sta->ampdu_mlme.tid_active_rx[tid]) {
 #ifdef CONFIG_MAC80211_HT_DEBUG
 		if (net_ratelimit())
 			printk(KERN_DEBUG "unexpected AddBA Req from "
@@ -273,7 +267,7 @@ void ieee80211_process_addba_request(struct ieee80211_local *local,
 	}
 
 	/* change state and send addba resp */
-	sta->ampdu_mlme.tid_state_rx[tid] = HT_AGG_STATE_OPERATIONAL;
+	sta->ampdu_mlme.tid_active_rx[tid] = true;
 	tid_agg_rx->dialog_token = dialog_token;
 	tid_agg_rx->ssn = start_seq_num;
 	tid_agg_rx->head_seq_num = start_seq_num;