mac80211: always set the buf_size in AddBA req to 64

Advertising reordering window in ADDBA less than 64 can crash some APs,
an example is LinkSys WRT120N (with FW v1.0.07 build 002 Jun 18 2012).
On the other hand, a driver may need to limit Tx A-MPDU size for its own
reasons, like specific HW limitations.

Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 82045fca388b20a9cf28ad9112236668c31f46cb..760bc4d5a2cfe87aadd2e96a98292855cf2eb050 100644 (file)
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -2003,8 +2003,10 @@ enum ieee80211_hw_flags {
  *     it shouldn't be set.
  *
  * @max_tx_aggregation_subframes: maximum number of subframes in an
- *     aggregate an HT driver will transmit, used by the peer as a
- *     hint to size its reorder buffer.
+ *     aggregate an HT driver will transmit. Though ADDBA will advertise
+ *     a constant value of 64 as some older APs can crash if the window
+ *     size is smaller (an example is LinkSys WRT120N with FW v1.0.07
+ *     build 002 Jun 18 2012).
  *
  * @offchannel_tx_hw_queue: HW queue ID to use for offchannel TX
  *     (if %IEEE80211_HW_QUEUE_CONTROL is set)

diff --git a/net/mac80211/agg-tx.c b/net/mac80211/agg-tx.c
index a758eb84e8f057ac6518eef6c73bc8785dc7e746..ff757181b0a85c820e1acc53a088e95c78b87bff 100644 (file)
--- a/net/mac80211/agg-tx.c
+++ b/net/mac80211/agg-tx.c
@@ -500,7 +500,7 @@ void ieee80211_tx_ba_session_handle_start(struct sta_info *sta, int tid)
        /* send AddBA request */
        ieee80211_send_addba_request(sdata, sta->sta.addr, tid,
                                     tid_tx->dialog_token, start_seq_num,
-                                    local->hw.max_tx_aggregation_subframes,
+                                    IEEE80211_MAX_AMPDU_BUF,
                                     tid_tx->timeout);
 }
 
@@ -926,6 +926,7 @@ void ieee80211_process_addba_resp(struct ieee80211_local *local,
        amsdu = capab & IEEE80211_ADDBA_PARAM_AMSDU_MASK;
        tid = (capab & IEEE80211_ADDBA_PARAM_TID_MASK) >> 2;
        buf_size = (capab & IEEE80211_ADDBA_PARAM_BUF_SIZE_MASK) >> 6;
+       buf_size = min(buf_size, local->hw.max_tx_aggregation_subframes);
 
        mutex_lock(&sta->ampdu_mlme.mtx);