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ath9k: reduce the number of unnecessary BAR tx packets
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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>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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Felix Fietkau authored and John W. Linville committed Dec 15, 2011
1 parent da64762 commit 156369f
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Showing 4 changed files with 37 additions and 23 deletions.
6 changes: 4 additions & 2 deletions drivers/net/wireless/ath/ath9k/ath9k.h
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Original file line number Diff line number Diff line change
Expand Up @@ -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 : \
Expand Down Expand Up @@ -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;
Expand All @@ -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
Expand Down
2 changes: 1 addition & 1 deletion drivers/net/wireless/ath/ath9k/debug.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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);
Expand Down
2 changes: 1 addition & 1 deletion drivers/net/wireless/ath/ath9k/main.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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 +
Expand Down
50 changes: 31 additions & 19 deletions drivers/net/wireless/ath/ath9k/xmit.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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,
Expand Down Expand Up @@ -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;
Expand All @@ -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);

Expand All @@ -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);
}
Expand All @@ -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,
Expand Down Expand Up @@ -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);
}

Expand Down Expand Up @@ -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;
Expand All @@ -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;
Expand All @@ -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;
}
Expand All @@ -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.
Expand Down Expand Up @@ -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));
}
}

Expand Down Expand Up @@ -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)) {
Expand All @@ -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;
}

Expand All @@ -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)
Expand Down Expand Up @@ -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);
}
}
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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;

Expand Down Expand Up @@ -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);

Expand Down

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