1 files changed, 38 insertions, 21 deletions

diff --git a/net/mac80211/agg-tx.c b/net/mac80211/agg-tx.c
index 53defafb9aae..c8be8eff70da 100644
--- a/net/mac80211/agg-tx.c
+++ b/net/mac80211/agg-tx.c
@@ -136,24 +136,35 @@ void ieee80211_send_bar(struct ieee80211_sub_if_data *sdata, u8 *ra, u16 tid, u1
         ieee80211_tx_skb(sdata, skb);
 }
 
+void ieee80211_assign_tid_tx(struct sta_info *sta, int tid,
+                             struct tid_ampdu_tx *tid_tx)
+{
+        lockdep_assert_held(&sta->ampdu_mlme.mtx);
+        lockdep_assert_held(&sta->lock);
+        rcu_assign_pointer(sta->ampdu_mlme.tid_tx[tid], tid_tx);
+}
+
 int ___ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
                                     enum ieee80211_back_parties initiator,
                                     bool tx)
 {
         struct ieee80211_local *local = sta->local;
-        struct tid_ampdu_tx *tid_tx = sta->ampdu_mlme.tid_tx[tid];
+        struct tid_ampdu_tx *tid_tx;
         int ret;
 
         lockdep_assert_held(&sta->ampdu_mlme.mtx);
 
-        if (!tid_tx)
-                return -ENOENT;
-
         spin_lock_bh(&sta->lock);
 
+        tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
+        if (!tid_tx) {
+                spin_unlock_bh(&sta->lock);
+                return -ENOENT;
+        }
+
         if (test_bit(HT_AGG_STATE_WANT_START, &tid_tx->state)) {
                 /* not even started yet! */
-                rcu_assign_pointer(sta->ampdu_mlme.tid_tx[tid], NULL);
+                ieee80211_assign_tid_tx(sta, tid, NULL);
                 spin_unlock_bh(&sta->lock);
                 kfree_rcu(tid_tx, rcu_head);
                 return 0;
@@ -275,13 +286,13 @@ ieee80211_wake_queue_agg(struct ieee80211_local *local, int tid)
 
 void ieee80211_tx_ba_session_handle_start(struct sta_info *sta, int tid)
 {
-        struct tid_ampdu_tx *tid_tx = sta->ampdu_mlme.tid_tx[tid];
+        struct tid_ampdu_tx *tid_tx;
         struct ieee80211_local *local = sta->local;
         struct ieee80211_sub_if_data *sdata = sta->sdata;
         u16 start_seq_num;
         int ret;
 
-        lockdep_assert_held(&sta->ampdu_mlme.mtx);
+        tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 
         /*
          * While we're asking the driver about the aggregation,
@@ -310,7 +321,7 @@ void ieee80211_tx_ba_session_handle_start(struct sta_info *sta, int tid)
                                         " tid %d\n", tid);
 #endif
                 spin_lock_bh(&sta->lock);
-                rcu_assign_pointer(sta->ampdu_mlme.tid_tx[tid], NULL);
+                ieee80211_assign_tid_tx(sta, tid, NULL);
                 spin_unlock_bh(&sta->lock);
 
                 ieee80211_wake_queue_agg(local, tid);
@@ -388,9 +399,9 @@ int ieee80211_start_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid,
                 goto err_unlock_sta;
         }
 
-        tid_tx = sta->ampdu_mlme.tid_tx[tid];
+        tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
         /* check if the TID is not in aggregation flow already */
-        if (tid_tx) {
+        if (tid_tx || sta->ampdu_mlme.tid_start_tx[tid]) {
 #ifdef CONFIG_MAC80211_HT_DEBUG
                 printk(KERN_DEBUG "BA request denied - session is not "
                                  "idle on tid %u\n", tid);
@@ -425,8 +436,11 @@ int ieee80211_start_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid,
         sta->ampdu_mlme.dialog_token_allocator++;
         tid_tx->dialog_token = sta->ampdu_mlme.dialog_token_allocator;
 
-        /* finally, assign it to the array */
-        rcu_assign_pointer(sta->ampdu_mlme.tid_tx[tid], tid_tx);
+        /*
+         * Finally, assign it to the start array; the work item will
+         * collect it and move it to the normal array.
+         */
+        sta->ampdu_mlme.tid_start_tx[tid] = tid_tx;
 
         ieee80211_queue_work(&local->hw, &sta->ampdu_mlme.work);
 
@@ -472,16 +486,19 @@ ieee80211_agg_splice_finish(struct ieee80211_local *local, u16 tid)
 static void ieee80211_agg_tx_operational(struct ieee80211_local *local,
                                          struct sta_info *sta, u16 tid)
 {
+        struct tid_ampdu_tx *tid_tx;
+
         lockdep_assert_held(&sta->ampdu_mlme.mtx);
 
+        tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
+
 #ifdef CONFIG_MAC80211_HT_DEBUG
         printk(KERN_DEBUG "Aggregation is on for tid %d\n", tid);
 #endif
 
         drv_ampdu_action(local, sta->sdata,
                          IEEE80211_AMPDU_TX_OPERATIONAL,
-                         &sta->sta, tid, NULL,
-                         sta->ampdu_mlme.tid_tx[tid]->buf_size);
+                         &sta->sta, tid, NULL, tid_tx->buf_size);
 
         /*
          * synchronize with TX path, while splicing the TX path
@@ -489,13 +506,13 @@ static void ieee80211_agg_tx_operational(struct ieee80211_local *local,
          */
         spin_lock_bh(&sta->lock);
 
-        ieee80211_agg_splice_packets(local, sta->ampdu_mlme.tid_tx[tid], tid);
+        ieee80211_agg_splice_packets(local, tid_tx, tid);
         /*
          * Now mark as operational. This will be visible
          * in the TX path, and lets it go lock-free in
          * the common case.
          */
-        set_bit(HT_AGG_STATE_OPERATIONAL, &sta->ampdu_mlme.tid_tx[tid]->state);
+        set_bit(HT_AGG_STATE_OPERATIONAL, &tid_tx->state);
         ieee80211_agg_splice_finish(local, tid);
 
         spin_unlock_bh(&sta->lock);
@@ -529,7 +546,7 @@ void ieee80211_start_tx_ba_cb(struct ieee80211_vif *vif, u8 *ra, u16 tid)
         }
 
         mutex_lock(&sta->ampdu_mlme.mtx);
-        tid_tx = sta->ampdu_mlme.tid_tx[tid];
+        tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 
         if (WARN_ON(!tid_tx)) {
 #ifdef CONFIG_MAC80211_HT_DEBUG
@@ -607,7 +624,7 @@ int ieee80211_stop_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid)
                 return -EINVAL;
 
         spin_lock_bh(&sta->lock);
-        tid_tx = sta->ampdu_mlme.tid_tx[tid];
+        tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 
         if (!tid_tx) {
                 ret = -ENOENT;
@@ -663,7 +680,7 @@ void ieee80211_stop_tx_ba_cb(struct ieee80211_vif *vif, u8 *ra, u8 tid)
 
         mutex_lock(&sta->ampdu_mlme.mtx);
         spin_lock_bh(&sta->lock);
-        tid_tx = sta->ampdu_mlme.tid_tx[tid];
+        tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 
         if (!tid_tx || !test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
 #ifdef CONFIG_MAC80211_HT_DEBUG
@@ -689,7 +706,7 @@ void ieee80211_stop_tx_ba_cb(struct ieee80211_vif *vif, u8 *ra, u8 tid)
         ieee80211_agg_splice_packets(local, tid_tx, tid);
 
         /* future packets must not find the tid_tx struct any more */
-        rcu_assign_pointer(sta->ampdu_mlme.tid_tx[tid], NULL);
+        ieee80211_assign_tid_tx(sta, tid, NULL);
 
         ieee80211_agg_splice_finish(local, tid);
 
@@ -744,7 +761,7 @@ void ieee80211_process_addba_resp(struct ieee80211_local *local,
 
         mutex_lock(&sta->ampdu_mlme.mtx);
 
-        tid_tx = sta->ampdu_mlme.tid_tx[tid];
+        tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
         if (!tid_tx)
                 goto out;