mac80211: support hw managing reorder logic

Enable driver to manage the reordering logic itself.
This is needed for example for the iwlwifi driver that
will support hardware assisted reordering.

Signed-off-by: Sara Sharon <sara.sharon@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

include/net/mac80211.h

@@ -1929,6 +1929,11 @@ struct ieee80211_txq {
  *	by just its MAC address; this prevents, for example, the same station
  *	from connecting to two virtual AP interfaces at the same time.
  *
+ * @IEEE80211_HW_SUPPORTS_REORDERING_BUFFER: Hardware (or driver) manages the
+ *	reordering buffer internally, guaranteeing mac80211 receives frames in
+ *	order and does not need to manage its own reorder buffer or BA session
+ *	timeout.
+ *
  * @NUM_IEEE80211_HW_FLAGS: number of hardware flags, used for sizing arrays
  */
 enum ieee80211_hw_flags {
@@ -1965,6 +1970,7 @@ enum ieee80211_hw_flags {
 	IEEE80211_HW_SUPPORTS_AMSDU_IN_AMPDU,
 	IEEE80211_HW_BEACON_TX_STATUS,
 	IEEE80211_HW_NEEDS_UNIQUE_STA_ADDR,
+	IEEE80211_HW_SUPPORTS_REORDERING_BUFFER,
 
 	/* keep last, obviously */
 	NUM_IEEE80211_HW_FLAGS

net/mac80211/agg-rx.c

@@ -76,10 +76,11 @@ void ___ieee80211_stop_rx_ba_session(struct sta_info *sta, u16 tid,
 	tid_rx = rcu_dereference_protected(sta->ampdu_mlme.tid_rx[tid],
 					lockdep_is_held(&sta->ampdu_mlme.mtx));
 
-	if (!tid_rx)
+	if (!test_bit(tid, sta->ampdu_mlme.agg_session_valid))
 		return;
 
 	RCU_INIT_POINTER(sta->ampdu_mlme.tid_rx[tid], NULL);
+	__clear_bit(tid, sta->ampdu_mlme.agg_session_valid);
 
 	ht_dbg(sta->sdata,
 	       "Rx BA session stop requested for %pM tid %u %s reason: %d\n",
@@ -97,6 +98,13 @@ void ___ieee80211_stop_rx_ba_session(struct sta_info *sta, u16 tid,
 		ieee80211_send_delba(sta->sdata, sta->sta.addr,
 				     tid, WLAN_BACK_RECIPIENT, reason);
 
+	/*
+	 * return here in case tid_rx is not assigned - which will happen if
+	 * IEEE80211_HW_SUPPORTS_REORDERING_BUFFER is set.
+	 */
+	if (!tid_rx)
+		return;
+
 	del_timer_sync(&tid_rx->session_timer);
 
 	/* make sure ieee80211_sta_reorder_release() doesn't re-arm the timer */
@@ -297,7 +305,7 @@ void __ieee80211_start_rx_ba_session(struct sta_info *sta,
 	/* examine state machine */
 	mutex_lock(&sta->ampdu_mlme.mtx);
 
-	if (sta->ampdu_mlme.tid_rx[tid]) {
+	if (test_bit(tid, sta->ampdu_mlme.agg_session_valid)) {
 		ht_dbg_ratelimited(sta->sdata,
 				   "unexpected AddBA Req from %pM on tid %u\n",
 				   sta->sta.addr, tid);
@@ -308,6 +316,16 @@ void __ieee80211_start_rx_ba_session(struct sta_info *sta,
 						false);
 	}
 
+	if (ieee80211_hw_check(&local->hw, SUPPORTS_REORDERING_BUFFER)) {
+		ret = drv_ampdu_action(local, sta->sdata, &params);
+		ht_dbg(sta->sdata,
+		       "Rx A-MPDU request on %pM tid %d result %d\n",
+		       sta->sta.addr, tid, ret);
+		if (!ret)
+			status = WLAN_STATUS_SUCCESS;
+		goto end;
+	}
+
 	/* prepare A-MPDU MLME for Rx aggregation */
 	tid_agg_rx = kmalloc(sizeof(struct tid_ampdu_rx), GFP_KERNEL);
 	if (!tid_agg_rx)
@@ -369,6 +387,8 @@ void __ieee80211_start_rx_ba_session(struct sta_info *sta,
 	}
 
 end:
+	if (status == WLAN_STATUS_SUCCESS)
+		__set_bit(tid, sta->ampdu_mlme.agg_session_valid);
 	mutex_unlock(&sta->ampdu_mlme.mtx);
 
 end_no_lock:

net/mac80211/debugfs.c

@@ -126,6 +126,7 @@ static const char *hw_flag_names[NUM_IEEE80211_HW_FLAGS + 1] = {
 	FLAG(SUPPORTS_AMSDU_IN_AMPDU),
 	FLAG(BEACON_TX_STATUS),
 	FLAG(NEEDS_UNIQUE_STA_ADDR),
+	FLAG(SUPPORTS_REORDERING_BUFFER),
 
 	/* keep last for the build bug below */
 	(void *)0x1

net/mac80211/sta_info.h

@@ -1,6 +1,7 @@
 /*
  * Copyright 2002-2005, Devicescape Software, Inc.
  * Copyright 2013-2014  Intel Mobile Communications GmbH
+ * Copyright(c) 2015 Intel Deutschland GmbH
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
@@ -212,20 +213,21 @@ struct tid_ampdu_rx {
 /**
  * struct sta_ampdu_mlme - STA aggregation information.
  *
+ * @mtx: mutex to protect all TX data (except non-NULL assignments
+ *	to tid_tx[idx], which are protected by the sta spinlock)
+ *	tid_start_tx is also protected by sta->lock.
  * @tid_rx: aggregation info for Rx per TID -- RCU protected
- * @tid_tx: aggregation info for Tx per TID
- * @tid_start_tx: sessions where start was requested
- * @addba_req_num: number of times addBA request has been sent.
- * @last_addba_req_time: timestamp of the last addBA request.
- * @dialog_token_allocator: dialog token enumerator for each new session;
- * @work: work struct for starting/stopping aggregation
  * @tid_rx_timer_expired: bitmap indicating on which TIDs the
  *	RX timer expired until the work for it runs
  * @tid_rx_stop_requested:  bitmap indicating which BA sessions per TID the
  *	driver requested to close until the work for it runs
- * @mtx: mutex to protect all TX data (except non-NULL assignments
- *	to tid_tx[idx], which are protected by the sta spinlock)
- *	tid_start_tx is also protected by sta->lock.
+ * @agg_session_valid: bitmap indicating which TID has a rx BA session open on
+ * @work: work struct for starting/stopping aggregation
+ * @tid_tx: aggregation info for Tx per TID
+ * @tid_start_tx: sessions where start was requested
+ * @last_addba_req_time: timestamp of the last addBA request.
+ * @addba_req_num: number of times addBA request has been sent.
+ * @dialog_token_allocator: dialog token enumerator for each new session;
  */
 struct sta_ampdu_mlme {
 	struct mutex mtx;
@@ -233,6 +235,7 @@ struct sta_ampdu_mlme {
 	struct tid_ampdu_rx __rcu *tid_rx[IEEE80211_NUM_TIDS];
 	unsigned long tid_rx_timer_expired[BITS_TO_LONGS(IEEE80211_NUM_TIDS)];
 	unsigned long tid_rx_stop_requested[BITS_TO_LONGS(IEEE80211_NUM_TIDS)];
+	unsigned long agg_session_valid[BITS_TO_LONGS(IEEE80211_NUM_TIDS)];
 	/* tx */
 	struct work_struct work;
 	struct tid_ampdu_tx __rcu *tid_tx[IEEE80211_NUM_TIDS];