1 files changed, 15 insertions, 19 deletions

diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 84f1173..ee01dac 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -719,16 +719,13 @@ static void ieee80211_rx_reorder_ampdu(struct ieee80211_rx_data *rx,
 
 	tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
 
-	spin_lock(&sta->lock);
-
-	if (!sta->ampdu_mlme.tid_active_rx[tid])
-		goto dont_reorder_unlock;
-
-	tid_agg_rx = sta->ampdu_mlme.tid_rx[tid];
+	tid_agg_rx = rcu_dereference(sta->ampdu_mlme.tid_rx[tid]);
+	if (!tid_agg_rx)
+		goto dont_reorder;
 
 	/* qos null data frames are excluded */
 	if (unlikely(hdr->frame_control & cpu_to_le16(IEEE80211_STYPE_NULLFUNC)))
-		goto dont_reorder_unlock;
+		goto dont_reorder;
 
 	/* new, potentially un-ordered, ampdu frame - process it */
 
@@ -740,20 +737,22 @@ static void ieee80211_rx_reorder_ampdu(struct ieee80211_rx_data *rx,
 	/* if this mpdu is fragmented - terminate rx aggregation session */
 	sc = le16_to_cpu(hdr->seq_ctrl);
 	if (sc & IEEE80211_SCTL_FRAG) {
-		spin_unlock(&sta->lock);
 		skb->pkt_type = IEEE80211_SDATA_QUEUE_TYPE_FRAME;
 		skb_queue_tail(&rx->sdata->skb_queue, skb);
 		ieee80211_queue_work(&local->hw, &rx->sdata->work);
 		return;
 	}
 
-	if (ieee80211_sta_manage_reorder_buf(hw, tid_agg_rx, skb, frames)) {
-		spin_unlock(&sta->lock);
+	/*
+	 * No locking needed -- we will only ever process one
+	 * RX packet at a time, and thus own tid_agg_rx. All
+	 * other code manipulating it needs to (and does) make
+	 * sure that we cannot get to it any more before doing
+	 * anything with it.
+	 */
+	if (ieee80211_sta_manage_reorder_buf(hw, tid_agg_rx, skb, frames))
 		return;
-	}
 
- dont_reorder_unlock:
-	spin_unlock(&sta->lock);
  dont_reorder:
 	__skb_queue_tail(frames, skb);
 }
@@ -1830,13 +1829,11 @@ ieee80211_rx_h_ctrl(struct ieee80211_rx_data *rx, struct sk_buff_head *frames)
 				  &bar_data, sizeof(bar_data)))
 			return RX_DROP_MONITOR;
 
-		spin_lock(&rx->sta->lock);
 		tid = le16_to_cpu(bar_data.control) >> 12;
-		if (!rx->sta->ampdu_mlme.tid_active_rx[tid]) {
-			spin_unlock(&rx->sta->lock);
+
+		tid_agg_rx = rcu_dereference(rx->sta->ampdu_mlme.tid_rx[tid]);
+		if (!tid_agg_rx)
 			return RX_DROP_MONITOR;
-		}
-		tid_agg_rx = rx->sta->ampdu_mlme.tid_rx[tid];
 
 		start_seq_num = le16_to_cpu(bar_data.start_seq_num) >> 4;
 
@@ -1849,7 +1846,6 @@ ieee80211_rx_h_ctrl(struct ieee80211_rx_data *rx, struct sk_buff_head *frames)
 		ieee80211_release_reorder_frames(hw, tid_agg_rx, start_seq_num,
 						 frames);
 		kfree_skb(skb);
-		spin_unlock(&rx->sta->lock);
 		return RX_QUEUED;
 	}