[PATCH 1/6] ath9k: change maximum software retransmission handling

[PATCH 1/6] ath9k: change maximum software retransmission handling

[Felix Fietkau]

Instead of limiting a subframe to 10 A-MPDU software transmission attempts,
count hardware retransmissions as well and raise the limit a bit. That way
there will be fewer software retransmission attempts when traffic suffers
from lots of hardware retransmissions.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
---
 drivers/net/wireless/ath/ath9k/ath9k.h |    2 +-
 drivers/net/wireless/ath/ath9k/xmit.c  |   15 ++++++++++++---
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/drivers/net/wireless/ath/ath9k/ath9k.h b/drivers/net/wireless/ath/ath9k/ath9k.h
index afc156a..fa6c905 100644
--- a/drivers/net/wireless/ath/ath9k/ath9k.h
+++ b/drivers/net/wireless/ath/ath9k/ath9k.h
@@ -542,7 +542,7 @@ struct ath_ant_comb {
 #define DEFAULT_CACHELINE       32
 #define ATH_REGCLASSIDS_MAX     10
 #define ATH_CABQ_READY_TIME     80      /* % of beacon interval */
-#define ATH_MAX_SW_RETRIES      10
+#define ATH_MAX_SW_RETRIES      30
 #define ATH_CHAN_MAX            255
 
 #define ATH_TXPOWER_MAX         100     /* .5 dBm units */
diff --git a/drivers/net/wireless/ath/ath9k/xmit.c b/drivers/net/wireless/ath/ath9k/xmit.c
index 9e65c31..a46b4e2 100644
--- a/drivers/net/wireless/ath/ath9k/xmit.c
+++ b/drivers/net/wireless/ath/ath9k/xmit.c
@@ -264,14 +264,17 @@ static void ath_tid_drain(struct ath_softc *sc, struct ath_txq *txq,
 }
 
 static void ath_tx_set_retry(struct ath_softc *sc, struct ath_txq *txq,
-			     struct sk_buff *skb)
+			     struct sk_buff *skb, int count)
 {
 	struct ath_frame_info *fi = get_frame_info(skb);
 	struct ath_buf *bf = fi->bf;
 	struct ieee80211_hdr *hdr;
+	int prev = fi->retries;
 
 	TX_STAT_INC(txq->axq_qnum, a_retries);
-	if (fi->retries++ > 0)
+	fi->retries += count;
+
+	if (prev > 0)
 		return;
 
 	hdr = (struct ieee80211_hdr *)skb->data;
@@ -379,6 +382,7 @@ static void ath_tx_complete_aggr(struct ath_softc *sc, struct ath_txq *txq,
 	int nframes;
 	u8 tidno;
 	bool flush = !!(ts->ts_status & ATH9K_TX_FLUSH);
+	int i, retries;
 
 	skb = bf->bf_mpdu;
 	hdr = (struct ieee80211_hdr *)skb->data;
@@ -387,6 +391,10 @@ static void ath_tx_complete_aggr(struct ath_softc *sc, struct ath_txq *txq,
 
 	memcpy(rates, tx_info->control.rates, sizeof(rates));
 
+	retries = ts->ts_longretry + 1;
+	for (i = 0; i < ts->ts_rateindex; i++)
+		retries += rates[i].count;
+
 	rcu_read_lock();
 
 	sta = ieee80211_find_sta_by_ifaddr(hw, hdr->addr1, hdr->addr2);
@@ -471,7 +479,8 @@ static void ath_tx_complete_aggr(struct ath_softc *sc, struct ath_txq *txq,
 				txpending = 1;
 			} else if (fi->retries < ATH_MAX_SW_RETRIES) {
 				if (txok || !an->sleeping)
-					ath_tx_set_retry(sc, txq, bf->bf_mpdu);
+					ath_tx_set_retry(sc, txq, bf->bf_mpdu,
+							 retries);
 
 				txpending = 1;
 			} else {
-- 
1.7.3.2

[PATCH 2/6] ath9k: reduce the number of unnecessary BAR tx packets

[Felix Fietkau]

When processing A-MPDU tx status, only send a BAR for the failed packet
with the highest sequence number.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
---
 drivers/net/wireless/ath/ath9k/ath9k.h |    6 ++-
 drivers/net/wireless/ath/ath9k/debug.c |    2 +-
 drivers/net/wireless/ath/ath9k/main.c  |    2 +-
 drivers/net/wireless/ath/ath9k/xmit.c  |   50 +++++++++++++++++++------------
 4 files changed, 37 insertions(+), 23 deletions(-)

diff --git a/drivers/net/wireless/ath/ath9k/ath9k.h b/drivers/net/wireless/ath/ath9k/ath9k.h
index fa6c905..6beaff5 100644
--- a/drivers/net/wireless/ath/ath9k/ath9k.h
+++ b/drivers/net/wireless/ath/ath9k/ath9k.h
@@ -159,6 +159,9 @@ void ath_descdma_cleanup(struct ath_softc *sc, struct ath_descdma *dd,
 /* return block-ack bitmap index given sequence and starting sequence */
 #define ATH_BA_INDEX(_st, _seq) (((_seq) - (_st)) & (IEEE80211_SEQ_MAX - 1))
 
+/* return the seqno for _start + _offset */
+#define ATH_BA_INDEX2SEQ(_seq, _offset) (((_seq) + (_offset)) & (IEEE80211_SEQ_MAX - 1))
+
 /* returns delimiter padding required given the packet length */
 #define ATH_AGGR_GET_NDELIM(_len)					\
        (((_len) >= ATH_AGGR_MINPLEN) ? 0 :                             \
@@ -252,9 +255,9 @@ struct ath_atx_tid {
 struct ath_node {
 #ifdef CONFIG_ATH9K_DEBUGFS
 	struct list_head list; /* for sc->nodes */
+#endif
 	struct ieee80211_sta *sta; /* station struct we're part of */
 	struct ieee80211_vif *vif; /* interface with which we're associated */
-#endif
 	struct ath_atx_tid tid[WME_NUM_TID];
 	struct ath_atx_ac ac[WME_NUM_AC];
 	int ps_key;
@@ -276,7 +279,6 @@ struct ath_tx_control {
 };
 
 #define ATH_TX_ERROR        0x01
-#define ATH_TX_BAR          0x02
 
 /**
  * @txq_map:  Index is mac80211 queue number.  This is
diff --git a/drivers/net/wireless/ath/ath9k/debug.c b/drivers/net/wireless/ath/ath9k/debug.c
index 6fb719d..5cb8cce 100644
--- a/drivers/net/wireless/ath/ath9k/debug.c
+++ b/drivers/net/wireless/ath/ath9k/debug.c
@@ -856,7 +856,7 @@ void ath_debug_stat_tx(struct ath_softc *sc, struct ath_buf *bf,
 	sc->debug.stats.txstats[qnum].tx_bytes_all += bf->bf_mpdu->len;
 
 	if (bf_isampdu(bf)) {
-		if (flags & ATH_TX_BAR)
+		if (flags & ATH_TX_ERROR)
 			TX_STAT_INC(qnum, a_xretries);
 		else
 			TX_STAT_INC(qnum, a_completed);
diff --git a/drivers/net/wireless/ath/ath9k/main.c b/drivers/net/wireless/ath/ath9k/main.c
index 7d92004..4475b0d 100644
--- a/drivers/net/wireless/ath/ath9k/main.c
+++ b/drivers/net/wireless/ath/ath9k/main.c
@@ -644,9 +644,9 @@ static void ath_node_attach(struct ath_softc *sc, struct ieee80211_sta *sta,
 	spin_lock(&sc->nodes_lock);
 	list_add(&an->list, &sc->nodes);
 	spin_unlock(&sc->nodes_lock);
+#endif
 	an->sta = sta;
 	an->vif = vif;
-#endif
 	if (sc->sc_flags & SC_OP_TXAGGR) {
 		ath_tx_node_init(sc, an);
 		an->maxampdu = 1 << (IEEE80211_HT_MAX_AMPDU_FACTOR +
diff --git a/drivers/net/wireless/ath/ath9k/xmit.c b/drivers/net/wireless/ath/ath9k/xmit.c
index a46b4e2..649a11e 100644
--- a/drivers/net/wireless/ath/ath9k/xmit.c
+++ b/drivers/net/wireless/ath/ath9k/xmit.c
@@ -53,7 +53,7 @@ static void ath_tx_complete(struct ath_softc *sc, struct sk_buff *skb,
 			    int tx_flags, struct ath_txq *txq);
 static void ath_tx_complete_buf(struct ath_softc *sc, struct ath_buf *bf,
 				struct ath_txq *txq, struct list_head *bf_q,
-				struct ath_tx_status *ts, int txok, int sendbar);
+				struct ath_tx_status *ts, int txok);
 static void ath_tx_txqaddbuf(struct ath_softc *sc, struct ath_txq *txq,
 			     struct list_head *head, bool internal);
 static void ath_tx_rc_status(struct ath_softc *sc, struct ath_buf *bf,
@@ -150,6 +150,12 @@ static struct ath_frame_info *get_frame_info(struct sk_buff *skb)
 	return (struct ath_frame_info *) &tx_info->rate_driver_data[0];
 }
 
+static void ath_send_bar(struct ath_atx_tid *tid, u16 seqno)
+{
+	ieee80211_send_bar(tid->an->vif, tid->an->sta->addr, tid->tidno,
+			   seqno << IEEE80211_SEQ_SEQ_SHIFT);
+}
+
 static void ath_tx_flush_tid(struct ath_softc *sc, struct ath_atx_tid *tid)
 {
 	struct ath_txq *txq = tid->ac->txq;
@@ -158,6 +164,7 @@ static void ath_tx_flush_tid(struct ath_softc *sc, struct ath_atx_tid *tid)
 	struct list_head bf_head;
 	struct ath_tx_status ts;
 	struct ath_frame_info *fi;
+	bool sendbar = false;
 
 	INIT_LIST_HEAD(&bf_head);
 
@@ -172,7 +179,8 @@ static void ath_tx_flush_tid(struct ath_softc *sc, struct ath_atx_tid *tid)
 		if (bf && fi->retries) {
 			list_add_tail(&bf->list, &bf_head);
 			ath_tx_update_baw(sc, tid, bf->bf_state.seqno);
-			ath_tx_complete_buf(sc, bf, txq, &bf_head, &ts, 0, 1);
+			ath_tx_complete_buf(sc, bf, txq, &bf_head, &ts, 0);
+			sendbar = true;
 		} else {
 			ath_tx_send_normal(sc, txq, NULL, skb);
 		}
@@ -185,6 +193,9 @@ static void ath_tx_flush_tid(struct ath_softc *sc, struct ath_atx_tid *tid)
 	}
 
 	spin_unlock_bh(&txq->axq_lock);
+
+	if (sendbar)
+		ath_send_bar(tid, tid->seq_start);
 }
 
 static void ath_tx_update_baw(struct ath_softc *sc, struct ath_atx_tid *tid,
@@ -255,7 +266,7 @@ static void ath_tid_drain(struct ath_softc *sc, struct ath_txq *txq,
 			ath_tx_update_baw(sc, tid, bf->bf_state.seqno);
 
 		spin_unlock(&txq->axq_lock);
-		ath_tx_complete_buf(sc, bf, txq, &bf_head, &ts, 0, 0);
+		ath_tx_complete_buf(sc, bf, txq, &bf_head, &ts, 0);
 		spin_lock(&txq->axq_lock);
 	}
 
@@ -373,7 +384,7 @@ static void ath_tx_complete_aggr(struct ath_softc *sc, struct ath_txq *txq,
 	struct ath_buf *bf_next, *bf_last = bf->bf_lastbf;
 	struct list_head bf_head;
 	struct sk_buff_head bf_pending;
-	u16 seq_st = 0, acked_cnt = 0, txfail_cnt = 0;
+	u16 seq_st = 0, acked_cnt = 0, txfail_cnt = 0, seq_first;
 	u32 ba[WME_BA_BMP_SIZE >> 5];
 	int isaggr, txfail, txpending, sendbar = 0, needreset = 0, nbad = 0;
 	bool rc_update = true;
@@ -383,6 +394,7 @@ static void ath_tx_complete_aggr(struct ath_softc *sc, struct ath_txq *txq,
 	u8 tidno;
 	bool flush = !!(ts->ts_status & ATH9K_TX_FLUSH);
 	int i, retries;
+	int bar_index = -1;
 
 	skb = bf->bf_mpdu;
 	hdr = (struct ieee80211_hdr *)skb->data;
@@ -408,8 +420,7 @@ static void ath_tx_complete_aggr(struct ath_softc *sc, struct ath_txq *txq,
 			if (!bf->bf_stale || bf_next != NULL)
 				list_move_tail(&bf->list, &bf_head);
 
-			ath_tx_complete_buf(sc, bf, txq, &bf_head, ts,
-				0, 0);
+			ath_tx_complete_buf(sc, bf, txq, &bf_head, ts, 0);
 
 			bf = bf_next;
 		}
@@ -419,6 +430,7 @@ static void ath_tx_complete_aggr(struct ath_softc *sc, struct ath_txq *txq,
 	an = (struct ath_node *)sta->drv_priv;
 	tidno = ieee80211_get_qos_ctl(hdr)[0] & IEEE80211_QOS_CTL_TID_MASK;
 	tid = ATH_AN_2_TID(an, tidno);
+	seq_first = tid->seq_start;
 
 	/*
 	 * The hardware occasionally sends a tx status for the wrong TID.
@@ -485,8 +497,9 @@ static void ath_tx_complete_aggr(struct ath_softc *sc, struct ath_txq *txq,
 				txpending = 1;
 			} else {
 				txfail = 1;
-				sendbar = 1;
 				txfail_cnt++;
+				bar_index = max_t(int, bar_index,
+					ATH_BA_INDEX(seq_first, seqno));
 			}
 		}
 
@@ -515,7 +528,7 @@ static void ath_tx_complete_aggr(struct ath_softc *sc, struct ath_txq *txq,
 			}
 
 			ath_tx_complete_buf(sc, bf, txq, &bf_head, ts,
-				!txfail, sendbar);
+				!txfail);
 		} else {
 			/* retry the un-acked ones */
 			if (!(sc->sc_ah->caps.hw_caps & ATH9K_HW_CAP_EDMA)) {
@@ -535,8 +548,10 @@ static void ath_tx_complete_aggr(struct ath_softc *sc, struct ath_txq *txq,
 
 						ath_tx_complete_buf(sc, bf, txq,
 								    &bf_head,
-								    ts, 0,
-								    !flush);
+								    ts, 0);
+						bar_index = max_t(int, bar_index,
+							ATH_BA_INDEX(seq_first,
+								seqno));
 						break;
 					}
 
@@ -554,6 +569,9 @@ static void ath_tx_complete_aggr(struct ath_softc *sc, struct ath_txq *txq,
 		bf = bf_next;
 	}
 
+	if (bar_index >= 0)
+		ath_send_bar(tid, ATH_BA_INDEX2SEQ(seq_first, bar_index + 1));
+
 	/* prepend un-acked frames to the beginning of the pending frame queue */
 	if (!skb_queue_empty(&bf_pending)) {
 		if (an->sleeping)
@@ -1441,7 +1459,7 @@ static void ath_drain_txq_list(struct ath_softc *sc, struct ath_txq *txq,
 			ath_tx_complete_aggr(sc, txq, bf, &bf_head, &ts, 0,
 					     retry_tx);
 		else
-			ath_tx_complete_buf(sc, bf, txq, &bf_head, &ts, 0, 0);
+			ath_tx_complete_buf(sc, bf, txq, &bf_head, &ts, 0);
 		spin_lock_bh(&txq->axq_lock);
 	}
 }
@@ -1945,9 +1963,6 @@ static void ath_tx_complete(struct ath_softc *sc, struct sk_buff *skb,
 
 	ath_dbg(common, ATH_DBG_XMIT, "TX complete: skb: %p\n", skb);
 
-	if (tx_flags & ATH_TX_BAR)
-		tx_info->flags |= IEEE80211_TX_STAT_AMPDU_NO_BACK;
-
 	if (!(tx_flags & ATH_TX_ERROR))
 		/* Frame was ACKed */
 		tx_info->flags |= IEEE80211_TX_STAT_ACK;
@@ -1991,16 +2006,13 @@ static void ath_tx_complete(struct ath_softc *sc, struct sk_buff *skb,
 
 static void ath_tx_complete_buf(struct ath_softc *sc, struct ath_buf *bf,
 				struct ath_txq *txq, struct list_head *bf_q,
-				struct ath_tx_status *ts, int txok, int sendbar)
+				struct ath_tx_status *ts, int txok)
 {
 	struct sk_buff *skb = bf->bf_mpdu;
 	struct ieee80211_tx_info *tx_info = IEEE80211_SKB_CB(skb);
 	unsigned long flags;
 	int tx_flags = 0;
 
-	if (sendbar)
-		tx_flags = ATH_TX_BAR;
-
 	if (!txok)
 		tx_flags |= ATH_TX_ERROR;
 
@@ -2107,7 +2119,7 @@ static void ath_tx_process_buffer(struct ath_softc *sc, struct ath_txq *txq,
 
 	if (!bf_isampdu(bf)) {
 		ath_tx_rc_status(sc, bf, ts, 1, txok ? 0 : 1, txok);
-		ath_tx_complete_buf(sc, bf, txq, bf_head, ts, txok, 0);
+		ath_tx_complete_buf(sc, bf, txq, bf_head, ts, txok);
 	} else
 		ath_tx_complete_aggr(sc, txq, bf, bf_head, ts, txok, true);
 
-- 
1.7.3.2

[PATCH 3/6] ath9k: reduce indentation level in a few places

[Felix Fietkau]

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
---
 drivers/net/wireless/ath/ath9k/xmit.c |  125 ++++++++++++++++-----------------
 1 files changed, 60 insertions(+), 65 deletions(-)

diff --git a/drivers/net/wireless/ath/ath9k/xmit.c b/drivers/net/wireless/ath/ath9k/xmit.c
index 649a11e..b1a37d2 100644
--- a/drivers/net/wireless/ath/ath9k/xmit.c
+++ b/drivers/net/wireless/ath/ath9k/xmit.c
@@ -480,27 +480,25 @@ static void ath_tx_complete_aggr(struct ath_softc *sc, struct ath_txq *txq,
 		} else if (!isaggr && txok) {
 			/* transmit completion */
 			acked_cnt++;
+		} else if ((tid->state & AGGR_CLEANUP) || !retry) {
+			/*
+			 * cleanup in progress, just fail
+			 * the un-acked sub-frames
+			 */
+			txfail = 1;
+		} else if (flush) {
+			txpending = 1;
+		} else if (fi->retries < ATH_MAX_SW_RETRIES) {
+			if (txok || !an->sleeping)
+				ath_tx_set_retry(sc, txq, bf->bf_mpdu,
+						 retries);
+
+			txpending = 1;
 		} else {
-			if ((tid->state & AGGR_CLEANUP) || !retry) {
-				/*
-				 * cleanup in progress, just fail
-				 * the un-acked sub-frames
-				 */
-				txfail = 1;
-			} else if (flush) {
-				txpending = 1;
-			} else if (fi->retries < ATH_MAX_SW_RETRIES) {
-				if (txok || !an->sleeping)
-					ath_tx_set_retry(sc, txq, bf->bf_mpdu,
-							 retries);
-
-				txpending = 1;
-			} else {
-				txfail = 1;
-				txfail_cnt++;
-				bar_index = max_t(int, bar_index,
-					ATH_BA_INDEX(seq_first, seqno));
-			}
+			txfail = 1;
+			txfail_cnt++;
+			bar_index = max_t(int, bar_index,
+				ATH_BA_INDEX(seq_first, seqno));
 		}
 
 		/*
@@ -531,32 +529,29 @@ static void ath_tx_complete_aggr(struct ath_softc *sc, struct ath_txq *txq,
 				!txfail);
 		} else {
 			/* retry the un-acked ones */
-			if (!(sc->sc_ah->caps.hw_caps & ATH9K_HW_CAP_EDMA)) {
-				if (bf->bf_next == NULL && bf_last->bf_stale) {
-					struct ath_buf *tbf;
-
-					tbf = ath_clone_txbuf(sc, bf_last);
-					/*
-					 * Update tx baw and complete the
-					 * frame with failed status if we
-					 * run out of tx buf.
-					 */
-					if (!tbf) {
-						spin_lock_bh(&txq->axq_lock);
-						ath_tx_update_baw(sc, tid, seqno);
-						spin_unlock_bh(&txq->axq_lock);
-
-						ath_tx_complete_buf(sc, bf, txq,
-								    &bf_head,
-								    ts, 0);
-						bar_index = max_t(int, bar_index,
-							ATH_BA_INDEX(seq_first,
-								seqno));
-						break;
-					}
-
-					fi->bf = tbf;
+			if (!(sc->sc_ah->caps.hw_caps & ATH9K_HW_CAP_EDMA) &&
+			    bf->bf_next == NULL && bf_last->bf_stale) {
+				struct ath_buf *tbf;
+
+				tbf = ath_clone_txbuf(sc, bf_last);
+				/*
+				 * Update tx baw and complete the
+				 * frame with failed status if we
+				 * run out of tx buf.
+				 */
+				if (!tbf) {
+					spin_lock_bh(&txq->axq_lock);
+					ath_tx_update_baw(sc, tid, seqno);
+					spin_unlock_bh(&txq->axq_lock);
+
+					ath_tx_complete_buf(sc, bf, txq,
+							    &bf_head, ts, 0);
+					bar_index = max_t(int, bar_index,
+						ATH_BA_INDEX(seq_first, seqno));
+					break;
 				}
+
+				fi->bf = tbf;
 			}
 
 			/*
@@ -644,24 +639,26 @@ static u32 ath_lookup_rate(struct ath_softc *sc, struct ath_buf *bf,
 	max_4ms_framelen = ATH_AMPDU_LIMIT_MAX;
 
 	for (i = 0; i < 4; i++) {
-		if (rates[i].count) {
-			int modeidx;
-			if (!(rates[i].flags & IEEE80211_TX_RC_MCS)) {
-				legacy = 1;
-				break;
-			}
-
-			if (rates[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH)
-				modeidx = MCS_HT40;
-			else
-				modeidx = MCS_HT20;
+		int modeidx;
 
-			if (rates[i].flags & IEEE80211_TX_RC_SHORT_GI)
-				modeidx++;
+		if (!rates[i].count)
+			continue;
 
-			frmlen = ath_max_4ms_framelen[modeidx][rates[i].idx];
-			max_4ms_framelen = min(max_4ms_framelen, frmlen);
+		if (!(rates[i].flags & IEEE80211_TX_RC_MCS)) {
+			legacy = 1;
+			break;
 		}
+
+		if (rates[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH)
+			modeidx = MCS_HT40;
+		else
+			modeidx = MCS_HT20;
+
+		if (rates[i].flags & IEEE80211_TX_RC_SHORT_GI)
+			modeidx++;
+
+		frmlen = ath_max_4ms_framelen[modeidx][rates[i].idx];
+		max_4ms_framelen = min(max_4ms_framelen, frmlen);
 	}
 
 	/*
@@ -1587,11 +1584,9 @@ void ath_txq_schedule(struct ath_softc *sc, struct ath_txq *txq)
 				break;
 		}
 
-		if (!list_empty(&ac->tid_q)) {
-			if (!ac->sched) {
-				ac->sched = true;
-				list_add_tail(&ac->list, &txq->axq_acq);
-			}
+		if (!list_empty(&ac->tid_q) && !ac->sched) {
+			ac->sched = true;
+			list_add_tail(&ac->list, &txq->axq_acq);
 		}
 
 		if (ac == last_ac ||
-- 
1.7.3.2

[PATCH 4/6] ath9k: remove bogus sequence number increment

[Felix Fietkau]

tid->seq_next is initialized on A-MPDU start anyway, and the comment next
to this chunk of code seems to be bogus as well.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
---
 drivers/net/wireless/ath/ath9k/xmit.c |    4 ----
 1 files changed, 0 insertions(+), 4 deletions(-)

diff --git a/drivers/net/wireless/ath/ath9k/xmit.c b/drivers/net/wireless/ath/ath9k/xmit.c
index b1a37d2..8f38efb 100644
--- a/drivers/net/wireless/ath/ath9k/xmit.c
+++ b/drivers/net/wireless/ath/ath9k/xmit.c
@@ -1729,10 +1729,6 @@ static void ath_tx_send_normal(struct ath_softc *sc, struct ath_txq *txq,
 	list_add_tail(&bf->list, &bf_head);
 	bf->bf_state.bf_type = 0;
 
-	/* update starting sequence number for subsequent ADDBA request */
-	if (tid)
-		INCR(tid->seq_start, IEEE80211_SEQ_MAX);
-
 	bf->bf_lastbf = bf;
 	ath_tx_fill_desc(sc, bf, txq, fi->framelen);
 	ath_tx_txqaddbuf(sc, txq, &bf_head, false);
-- 
1.7.3.2

[PATCH 5/6] ath9k: simplify tx locking

[Felix Fietkau]

Instead of releasing and taking back the lock over and over again in the
tx path, hold the lock a bit longer, requiring much fewer lock/unlock pairs.
This makes locking much easier to review and should not have any noticeable
performance/latency impact.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
---
 drivers/net/wireless/ath/ath9k/xmit.c |   50 ++++++---------------------------
 1 files changed, 9 insertions(+), 41 deletions(-)

diff --git a/drivers/net/wireless/ath/ath9k/xmit.c b/drivers/net/wireless/ath/ath9k/xmit.c
index 8f38efb..6303c0f 100644
--- a/drivers/net/wireless/ath/ath9k/xmit.c
+++ b/drivers/net/wireless/ath/ath9k/xmit.c
@@ -169,13 +169,11 @@ static void ath_tx_flush_tid(struct ath_softc *sc, struct ath_atx_tid *tid)
 	INIT_LIST_HEAD(&bf_head);
 
 	memset(&ts, 0, sizeof(ts));
-	spin_lock_bh(&txq->axq_lock);
 
 	while ((skb = __skb_dequeue(&tid->buf_q))) {
 		fi = get_frame_info(skb);
 		bf = fi->bf;
 
-		spin_unlock_bh(&txq->axq_lock);
 		if (bf && fi->retries) {
 			list_add_tail(&bf->list, &bf_head);
 			ath_tx_update_baw(sc, tid, bf->bf_state.seqno);
@@ -184,7 +182,6 @@ static void ath_tx_flush_tid(struct ath_softc *sc, struct ath_atx_tid *tid)
 		} else {
 			ath_tx_send_normal(sc, txq, NULL, skb);
 		}
-		spin_lock_bh(&txq->axq_lock);
 	}
 
 	if (tid->baw_head == tid->baw_tail) {
@@ -192,8 +189,6 @@ static void ath_tx_flush_tid(struct ath_softc *sc, struct ath_atx_tid *tid)
 		tid->state &= ~AGGR_CLEANUP;
 	}
 
-	spin_unlock_bh(&txq->axq_lock);
-
 	if (sendbar)
 		ath_send_bar(tid, tid->seq_start);
 }
@@ -254,9 +249,7 @@ static void ath_tid_drain(struct ath_softc *sc, struct ath_txq *txq,
 		bf = fi->bf;
 
 		if (!bf) {
-			spin_unlock(&txq->axq_lock);
 			ath_tx_complete(sc, skb, ATH_TX_ERROR, txq);
-			spin_lock(&txq->axq_lock);
 			continue;
 		}
 
@@ -265,9 +258,7 @@ static void ath_tid_drain(struct ath_softc *sc, struct ath_txq *txq,
 		if (fi->retries)
 			ath_tx_update_baw(sc, tid, bf->bf_state.seqno);
 
-		spin_unlock(&txq->axq_lock);
 		ath_tx_complete_buf(sc, bf, txq, &bf_head, &ts, 0);
-		spin_lock(&txq->axq_lock);
 	}
 
 	tid->seq_next = tid->seq_start;
@@ -515,9 +506,7 @@ static void ath_tx_complete_aggr(struct ath_softc *sc, struct ath_txq *txq,
 			 * complete the acked-ones/xretried ones; update
 			 * block-ack window
 			 */
-			spin_lock_bh(&txq->axq_lock);
 			ath_tx_update_baw(sc, tid, seqno);
-			spin_unlock_bh(&txq->axq_lock);
 
 			if (rc_update && (acked_cnt == 1 || txfail_cnt == 1)) {
 				memcpy(tx_info->control.rates, rates, sizeof(rates));
@@ -540,9 +529,7 @@ static void ath_tx_complete_aggr(struct ath_softc *sc, struct ath_txq *txq,
 				 * run out of tx buf.
 				 */
 				if (!tbf) {
-					spin_lock_bh(&txq->axq_lock);
 					ath_tx_update_baw(sc, tid, seqno);
-					spin_unlock_bh(&txq->axq_lock);
 
 					ath_tx_complete_buf(sc, bf, txq,
 							    &bf_head, ts, 0);
@@ -572,7 +559,6 @@ static void ath_tx_complete_aggr(struct ath_softc *sc, struct ath_txq *txq,
 		if (an->sleeping)
 			ieee80211_sta_set_buffered(sta, tid->tidno, true);
 
-		spin_lock_bh(&txq->axq_lock);
 		skb_queue_splice(&bf_pending, &tid->buf_q);
 		if (!an->sleeping) {
 			ath_tx_queue_tid(txq, tid);
@@ -580,7 +566,6 @@ static void ath_tx_complete_aggr(struct ath_softc *sc, struct ath_txq *txq,
 			if (ts->ts_status & ATH9K_TXERR_FILT)
 				tid->ac->clear_ps_filter = true;
 		}
-		spin_unlock_bh(&txq->axq_lock);
 	}
 
 	if (tid->state & AGGR_CLEANUP)
@@ -1179,9 +1164,9 @@ void ath_tx_aggr_stop(struct ath_softc *sc, struct ieee80211_sta *sta, u16 tid)
 		txtid->state |= AGGR_CLEANUP;
 	else
 		txtid->state &= ~AGGR_ADDBA_COMPLETE;
-	spin_unlock_bh(&txq->axq_lock);
 
 	ath_tx_flush_tid(sc, txtid);
+	spin_unlock_bh(&txq->axq_lock);
 }
 
 void ath_tx_aggr_sleep(struct ieee80211_sta *sta, struct ath_softc *sc,
@@ -1423,8 +1408,6 @@ static bool bf_is_ampdu_not_probing(struct ath_buf *bf)
 
 static void ath_drain_txq_list(struct ath_softc *sc, struct ath_txq *txq,
 			       struct list_head *list, bool retry_tx)
-	__releases(txq->axq_lock)
-	__acquires(txq->axq_lock)
 {
 	struct ath_buf *bf, *lastbf;
 	struct list_head bf_head;
@@ -1451,13 +1434,11 @@ static void ath_drain_txq_list(struct ath_softc *sc, struct ath_txq *txq,
 		if (bf_is_ampdu_not_probing(bf))
 			txq->axq_ampdu_depth--;
 
-		spin_unlock_bh(&txq->axq_lock);
 		if (bf_isampdu(bf))
 			ath_tx_complete_aggr(sc, txq, bf, &bf_head, &ts, 0,
 					     retry_tx);
 		else
 			ath_tx_complete_buf(sc, bf, txq, &bf_head, &ts, 0);
-		spin_lock_bh(&txq->axq_lock);
 	}
 }
 
@@ -1836,7 +1817,6 @@ static void ath_tx_start_dma(struct ath_softc *sc, struct sk_buff *skb,
 	struct ath_buf *bf;
 	u8 tidno;
 
-	spin_lock_bh(&txctl->txq->axq_lock);
 	if ((sc->sc_flags & SC_OP_TXAGGR) && txctl->an &&
 		ieee80211_is_data_qos(hdr->frame_control)) {
 		tidno = ieee80211_get_qos_ctl(hdr)[0] &
@@ -1855,7 +1835,7 @@ static void ath_tx_start_dma(struct ath_softc *sc, struct sk_buff *skb,
 	} else {
 		bf = ath_tx_setup_buffer(sc, txctl->txq, tid, skb);
 		if (!bf)
-			goto out;
+			return;
 
 		bf->bf_state.bfs_paprd = txctl->paprd;
 
@@ -1864,9 +1844,6 @@ static void ath_tx_start_dma(struct ath_softc *sc, struct sk_buff *skb,
 
 		ath_tx_send_normal(sc, txctl->txq, tid, skb);
 	}
-
-out:
-	spin_unlock_bh(&txctl->txq->axq_lock);
 }
 
 /* Upon failure caller should free skb */
@@ -1933,9 +1910,11 @@ int ath_tx_start(struct ieee80211_hw *hw, struct sk_buff *skb,
 		ieee80211_stop_queue(sc->hw, q);
 		txq->stopped = 1;
 	}
-	spin_unlock_bh(&txq->axq_lock);
 
 	ath_tx_start_dma(sc, skb, txctl);
+
+	spin_unlock_bh(&txq->axq_lock);
+
 	return 0;
 }
 
@@ -1981,7 +1960,6 @@ static void ath_tx_complete(struct ath_softc *sc, struct sk_buff *skb,
 
 	q = skb_get_queue_mapping(skb);
 	if (txq == sc->tx.txq_map[q]) {
-		spin_lock_bh(&txq->axq_lock);
 		if (WARN_ON(--txq->pending_frames < 0))
 			txq->pending_frames = 0;
 
@@ -1989,7 +1967,6 @@ static void ath_tx_complete(struct ath_softc *sc, struct sk_buff *skb,
 			ieee80211_wake_queue(sc->hw, q);
 			txq->stopped = 0;
 		}
-		spin_unlock_bh(&txq->axq_lock);
 	}
 
 	ieee80211_tx_status(hw, skb);
@@ -2095,8 +2072,6 @@ static void ath_tx_rc_status(struct ath_softc *sc, struct ath_buf *bf,
 static void ath_tx_process_buffer(struct ath_softc *sc, struct ath_txq *txq,
 				  struct ath_tx_status *ts, struct ath_buf *bf,
 				  struct list_head *bf_head)
-	__releases(txq->axq_lock)
-	__acquires(txq->axq_lock)
 {
 	int txok;
 
@@ -2106,16 +2081,12 @@ static void ath_tx_process_buffer(struct ath_softc *sc, struct ath_txq *txq,
 	if (bf_is_ampdu_not_probing(bf))
 		txq->axq_ampdu_depth--;
 
-	spin_unlock_bh(&txq->axq_lock);
-
 	if (!bf_isampdu(bf)) {
 		ath_tx_rc_status(sc, bf, ts, 1, txok ? 0 : 1, txok);
 		ath_tx_complete_buf(sc, bf, txq, bf_head, ts, txok);
 	} else
 		ath_tx_complete_aggr(sc, txq, bf, bf_head, ts, txok, true);
 
-	spin_lock_bh(&txq->axq_lock);
-
 	if (sc->sc_flags & SC_OP_TXAGGR)
 		ath_txq_schedule(sc, txq);
 }
@@ -2259,6 +2230,7 @@ void ath_tx_edma_tasklet(struct ath_softc *sc)
 	struct list_head bf_head;
 	int status;
 
+	spin_lock_bh(&txq->axq_lock);
 	for (;;) {
 		if (work_pending(&sc->hw_reset_work))
 			break;
@@ -2278,12 +2250,8 @@ void ath_tx_edma_tasklet(struct ath_softc *sc)
 
 		txq = &sc->tx.txq[ts.qid];
 
-		spin_lock_bh(&txq->axq_lock);
-
-		if (list_empty(&txq->txq_fifo[txq->txq_tailidx])) {
-			spin_unlock_bh(&txq->axq_lock);
-			return;
-		}
+		if (list_empty(&txq->txq_fifo[txq->txq_tailidx]))
+			break;
 
 		bf = list_first_entry(&txq->txq_fifo[txq->txq_tailidx],
 				      struct ath_buf, list);
@@ -2307,8 +2275,8 @@ void ath_tx_edma_tasklet(struct ath_softc *sc)
 		}
 
 		ath_tx_process_buffer(sc, txq, &ts, bf, &bf_head);
-		spin_unlock_bh(&txq->axq_lock);
 	}
+	spin_unlock_bh(&txq->axq_lock);
 }
 
 /*****************/
-- 
1.7.3.2

[PATCH 6/6] ath9k: avoid retransmitting aggregation frames that a BAR was sent for

[Felix Fietkau]

The receiver will discard them anyway.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
---
 drivers/net/wireless/ath/ath9k/ath9k.h |    1 +
 drivers/net/wireless/ath/ath9k/xmit.c  |   27 ++++++++++++++++++++++++---
 2 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/drivers/net/wireless/ath/ath9k/ath9k.h b/drivers/net/wireless/ath/ath9k/ath9k.h
index 6beaff5..130e5db 100644
--- a/drivers/net/wireless/ath/ath9k/ath9k.h
+++ b/drivers/net/wireless/ath/ath9k/ath9k.h
@@ -241,6 +241,7 @@ struct ath_atx_tid {
 	struct ath_node *an;
 	struct ath_atx_ac *ac;
 	unsigned long tx_buf[BITS_TO_LONGS(ATH_TID_MAX_BUFS)];
+	int bar_index;
 	u16 seq_start;
 	u16 seq_next;
 	u16 baw_size;
diff --git a/drivers/net/wireless/ath/ath9k/xmit.c b/drivers/net/wireless/ath/ath9k/xmit.c
index 6303c0f..3473da3 100644
--- a/drivers/net/wireless/ath/ath9k/xmit.c
+++ b/drivers/net/wireless/ath/ath9k/xmit.c
@@ -206,6 +206,8 @@ static void ath_tx_update_baw(struct ath_softc *sc, struct ath_atx_tid *tid,
 	while (tid->baw_head != tid->baw_tail && !test_bit(tid->baw_head, tid->tx_buf)) {
 		INCR(tid->seq_start, IEEE80211_SEQ_MAX);
 		INCR(tid->baw_head, ATH_TID_MAX_BUFS);
+		if (tid->bar_index >= 0)
+			tid->bar_index--;
 	}
 }
 
@@ -263,6 +265,7 @@ static void ath_tid_drain(struct ath_softc *sc, struct ath_txq *txq,
 
 	tid->seq_next = tid->seq_start;
 	tid->baw_tail = tid->baw_head;
+	tid->bar_index = -1;
 }
 
 static void ath_tx_set_retry(struct ath_softc *sc, struct ath_txq *txq,
@@ -551,8 +554,12 @@ static void ath_tx_complete_aggr(struct ath_softc *sc, struct ath_txq *txq,
 		bf = bf_next;
 	}
 
-	if (bar_index >= 0)
+	if (bar_index >= 0) {
+		u16 bar_seq = ATH_BA_INDEX2SEQ(seq_first, bar_index);
 		ath_send_bar(tid, ATH_BA_INDEX2SEQ(seq_first, bar_index + 1));
+		if (BAW_WITHIN(tid->seq_start, tid->baw_size, bar_seq))
+			tid->bar_index = ATH_BA_INDEX(tid->seq_start, bar_seq);
+	}
 
 	/* prepend un-acked frames to the beginning of the pending frame queue */
 	if (!skb_queue_empty(&bf_pending)) {
@@ -779,8 +786,6 @@ static enum ATH_AGGR_STATUS ath_tx_form_aggr(struct ath_softc *sc,
 
 		bf->bf_state.bf_type = BUF_AMPDU | BUF_AGGR;
 		seqno = bf->bf_state.seqno;
-		if (!bf_first)
-			bf_first = bf;
 
 		/* do not step over block-ack window */
 		if (!BAW_WITHIN(tid->seq_start, tid->baw_size, seqno)) {
@@ -788,6 +793,21 @@ static enum ATH_AGGR_STATUS ath_tx_form_aggr(struct ath_softc *sc,
 			break;
 		}
 
+		if (tid->bar_index > ATH_BA_INDEX(tid->seq_start, seqno)) {
+			struct ath_tx_status ts = {};
+			struct list_head bf_head;
+
+			INIT_LIST_HEAD(&bf_head);
+			list_add(&bf->list, &bf_head);
+			__skb_unlink(skb, &tid->buf_q);
+			ath_tx_update_baw(sc, tid, seqno);
+			ath_tx_complete_buf(sc, bf, txq, &bf_head, &ts, 0);
+			continue;
+		}
+
+		if (!bf_first)
+			bf_first = bf;
+
 		if (!rl) {
 			aggr_limit = ath_lookup_rate(sc, bf, tid);
 			rl = 1;
@@ -1130,6 +1150,7 @@ int ath_tx_aggr_start(struct ath_softc *sc, struct ieee80211_sta *sta,
 	txtid->state |= AGGR_ADDBA_PROGRESS;
 	txtid->paused = true;
 	*ssn = txtid->seq_start = txtid->seq_next;
+	txtid->bar_index = -1;
 
 	memset(txtid->tx_buf, 0, sizeof(txtid->tx_buf));
 	txtid->baw_head = txtid->baw_tail = 0;
-- 
1.7.3.2

Re: [PATCH 5/6] ath9k: simplify tx locking

[John W. Linville]

On Mon, Dec 12, 2011 at 09:06:25PM +0100, Felix Fietkau wrote:
> Instead of releasing and taking back the lock over and over again in the
> tx path, hold the lock a bit longer, requiring much fewer lock/unlock pairs.
> This makes locking much easier to review and should not have any noticeable
> performance/latency impact.
> 
> Signed-off-by: Felix Fietkau <nbd@openwrt.org>

> @@ -2259,6 +2230,7 @@ void ath_tx_edma_tasklet(struct ath_softc *sc)
>  	struct list_head bf_head;
>  	int status;
>  
> +	spin_lock_bh(&txq->axq_lock);
>  	for (;;) {
>  		if (work_pending(&sc->hw_reset_work))
>  			break;

Pretty sure this is wrong -- gcc seems to agree:

  CC [M]  drivers/net/wireless/ath/ath9k/xmit.o
drivers/net/wireless/ath/ath9k/xmit.c: In function ‘ath_tx_edma_tasklet’:
drivers/net/wireless/ath/ath9k/xmit.c:2249:18: warning: ‘txq’ may be used uninitialized in this function

> @@ -2278,12 +2250,8 @@ void ath_tx_edma_tasklet(struct ath_softc *sc)
>  
>  		txq = &sc->tx.txq[ts.qid];
>  
> -		spin_lock_bh(&txq->axq_lock);
> -
> -		if (list_empty(&txq->txq_fifo[txq->txq_tailidx])) {
> -			spin_unlock_bh(&txq->axq_lock);
> -			return;
> -		}
> +		if (list_empty(&txq->txq_fifo[txq->txq_tailidx]))
> +			break;
>  
>  		bf = list_first_entry(&txq->txq_fifo[txq->txq_tailidx],
>  				      struct ath_buf, list);

Looks like txq doesn't get initialized until this loop?

-- 
John W. Linville		Someday the world will need a hero, and you
linville@tuxdriver.com			might be all we have.  Be ready.