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ath9k: fix tx locking issues
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The commit "ath9k: simplify tx locking" introduced a soft lockup triggered
by mac80211 sending a BAR frame triggered by a driver call to
ieee80211_tx_send_bar or ieee80211_tx_status.
Fix these issues by queueing processed tx status skbs and submitting them
to mac80211 outside of the lock.

Signed-off-by: Felix Fietkau <[email protected]>
Signed-off-by: Mohammed Shafi Shajakhan <[email protected]>
Signed-off-by: John W. Linville <[email protected]>
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@linvjw
Felix Fietkau authored and linvjw committed Dec 19, 2011
1 parent 8a30930 commit 23de5dc
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Showing 2 changed files with 65 additions and 32 deletions.
1 change: 1 addition & 0 deletions drivers/net/wireless/ath/ath9k/ath9k.h
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Original file line number Diff line number Diff line change
Expand Up @@ -196,6 +196,7 @@ struct ath_txq {
u8 txq_headidx;
u8 txq_tailidx;
int pending_frames;
struct sk_buff_head complete_q;
};

struct ath_atx_ac {
Expand Down
96 changes: 64 additions & 32 deletions drivers/net/wireless/ath/ath9k/xmit.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -104,6 +104,29 @@ static int ath_max_4ms_framelen[4][32] = {
/* Aggregation logic */
/*********************/

static void ath_txq_lock(struct ath_softc *sc, struct ath_txq *txq)
{
spin_lock_bh(&txq->axq_lock);
}

static void ath_txq_unlock(struct ath_softc *sc, struct ath_txq *txq)
{
spin_unlock_bh(&txq->axq_lock);
}

static void ath_txq_unlock_complete(struct ath_softc *sc, struct ath_txq *txq)
{
struct sk_buff_head q;
struct sk_buff *skb;

__skb_queue_head_init(&q);
skb_queue_splice_init(&txq->complete_q, &q);
spin_unlock_bh(&txq->axq_lock);

while ((skb = __skb_dequeue(&q)))
ieee80211_tx_status(sc->hw, skb);
}

static void ath_tx_queue_tid(struct ath_txq *txq, struct ath_atx_tid *tid)
{
struct ath_atx_ac *ac = tid->ac;
Expand All @@ -130,7 +153,7 @@ static void ath_tx_resume_tid(struct ath_softc *sc, struct ath_atx_tid *tid)

WARN_ON(!tid->paused);

spin_lock_bh(&txq->axq_lock);
ath_txq_lock(sc, txq);
tid->paused = false;

if (skb_queue_empty(&tid->buf_q))
Expand All @@ -139,7 +162,7 @@ static void ath_tx_resume_tid(struct ath_softc *sc, struct ath_atx_tid *tid)
ath_tx_queue_tid(txq, tid);
ath_txq_schedule(sc, txq);
unlock:
spin_unlock_bh(&txq->axq_lock);
ath_txq_unlock_complete(sc, txq);
}

static struct ath_frame_info *get_frame_info(struct sk_buff *skb)
Expand Down Expand Up @@ -189,8 +212,11 @@ static void ath_tx_flush_tid(struct ath_softc *sc, struct ath_atx_tid *tid)
tid->state &= ~AGGR_CLEANUP;
}

if (sendbar)
if (sendbar) {
ath_txq_unlock(sc, txq);
ath_send_bar(tid, tid->seq_start);
ath_txq_lock(sc, txq);
}
}

static void ath_tx_update_baw(struct ath_softc *sc, struct ath_atx_tid *tid,
Expand Down Expand Up @@ -554,13 +580,6 @@ static void ath_tx_complete_aggr(struct ath_softc *sc, struct ath_txq *txq,
bf = bf_next;
}

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)) {
if (an->sleeping)
Expand All @@ -575,6 +594,17 @@ static void ath_tx_complete_aggr(struct ath_softc *sc, struct ath_txq *txq,
}
}

if (bar_index >= 0) {
u16 bar_seq = ATH_BA_INDEX2SEQ(seq_first, bar_index);

if (BAW_WITHIN(tid->seq_start, tid->baw_size, bar_seq))
tid->bar_index = ATH_BA_INDEX(tid->seq_start, bar_seq);

ath_txq_unlock(sc, txq);
ath_send_bar(tid, ATH_BA_INDEX2SEQ(seq_first, bar_index + 1));
ath_txq_lock(sc, txq);
}

if (tid->state & AGGR_CLEANUP)
ath_tx_flush_tid(sc, tid);

Expand Down Expand Up @@ -1172,7 +1202,7 @@ void ath_tx_aggr_stop(struct ath_softc *sc, struct ieee80211_sta *sta, u16 tid)
return;
}

spin_lock_bh(&txq->axq_lock);
ath_txq_lock(sc, txq);
txtid->paused = true;

/*
Expand All @@ -1187,7 +1217,7 @@ void ath_tx_aggr_stop(struct ath_softc *sc, struct ieee80211_sta *sta, u16 tid)
txtid->state &= ~AGGR_ADDBA_COMPLETE;

ath_tx_flush_tid(sc, txtid);
spin_unlock_bh(&txq->axq_lock);
ath_txq_unlock_complete(sc, txq);
}

void ath_tx_aggr_sleep(struct ieee80211_sta *sta, struct ath_softc *sc,
Expand All @@ -1208,7 +1238,7 @@ void ath_tx_aggr_sleep(struct ieee80211_sta *sta, struct ath_softc *sc,
ac = tid->ac;
txq = ac->txq;

spin_lock_bh(&txq->axq_lock);
ath_txq_lock(sc, txq);

buffered = !skb_queue_empty(&tid->buf_q);

Expand All @@ -1220,7 +1250,7 @@ void ath_tx_aggr_sleep(struct ieee80211_sta *sta, struct ath_softc *sc,
list_del(&ac->list);
}

spin_unlock_bh(&txq->axq_lock);
ath_txq_unlock(sc, txq);

ieee80211_sta_set_buffered(sta, tidno, buffered);
}
Expand All @@ -1239,15 +1269,15 @@ void ath_tx_aggr_wakeup(struct ath_softc *sc, struct ath_node *an)
ac = tid->ac;
txq = ac->txq;

spin_lock_bh(&txq->axq_lock);
ath_txq_lock(sc, txq);
ac->clear_ps_filter = true;

if (!skb_queue_empty(&tid->buf_q) && !tid->paused) {
ath_tx_queue_tid(txq, tid);
ath_txq_schedule(sc, txq);
}

spin_unlock_bh(&txq->axq_lock);
ath_txq_unlock_complete(sc, txq);
}
}

Expand Down Expand Up @@ -1347,6 +1377,7 @@ struct ath_txq *ath_txq_setup(struct ath_softc *sc, int qtype, int subtype)
txq->axq_qnum = axq_qnum;
txq->mac80211_qnum = -1;
txq->axq_link = NULL;
__skb_queue_head_init(&txq->complete_q);
INIT_LIST_HEAD(&txq->axq_q);
INIT_LIST_HEAD(&txq->axq_acq);
spin_lock_init(&txq->axq_lock);
Expand Down Expand Up @@ -1471,7 +1502,8 @@ static void ath_drain_txq_list(struct ath_softc *sc, struct ath_txq *txq,
*/
void ath_draintxq(struct ath_softc *sc, struct ath_txq *txq, bool retry_tx)
{
spin_lock_bh(&txq->axq_lock);
ath_txq_lock(sc, txq);

if (sc->sc_ah->caps.hw_caps & ATH9K_HW_CAP_EDMA) {
int idx = txq->txq_tailidx;

Expand All @@ -1492,7 +1524,7 @@ void ath_draintxq(struct ath_softc *sc, struct ath_txq *txq, bool retry_tx)
if ((sc->sc_flags & SC_OP_TXAGGR) && !retry_tx)
ath_txq_drain_pending_buffers(sc, txq);

spin_unlock_bh(&txq->axq_lock);
ath_txq_unlock_complete(sc, txq);
}

bool ath_drain_all_txq(struct ath_softc *sc, bool retry_tx)
Expand Down Expand Up @@ -1924,7 +1956,8 @@ int ath_tx_start(struct ieee80211_hw *hw, struct sk_buff *skb,
*/

q = skb_get_queue_mapping(skb);
spin_lock_bh(&txq->axq_lock);

ath_txq_lock(sc, txq);
if (txq == sc->tx.txq_map[q] &&
++txq->pending_frames > ATH_MAX_QDEPTH && !txq->stopped) {
ieee80211_stop_queue(sc->hw, q);
Expand All @@ -1933,7 +1966,7 @@ int ath_tx_start(struct ieee80211_hw *hw, struct sk_buff *skb,

ath_tx_start_dma(sc, skb, txctl);

spin_unlock_bh(&txq->axq_lock);
ath_txq_unlock(sc, txq);

return 0;
}
Expand All @@ -1945,7 +1978,6 @@ int ath_tx_start(struct ieee80211_hw *hw, struct sk_buff *skb,
static void ath_tx_complete(struct ath_softc *sc, struct sk_buff *skb,
int tx_flags, struct ath_txq *txq)
{
struct ieee80211_hw *hw = sc->hw;
struct ieee80211_tx_info *tx_info = IEEE80211_SKB_CB(skb);
struct ath_common *common = ath9k_hw_common(sc->sc_ah);
struct ieee80211_hdr * hdr = (struct ieee80211_hdr *)skb->data;
Expand Down Expand Up @@ -1989,7 +2021,7 @@ static void ath_tx_complete(struct ath_softc *sc, struct sk_buff *skb,
}
}

ieee80211_tx_status(hw, skb);
__skb_queue_tail(&txq->complete_q, skb);
}

static void ath_tx_complete_buf(struct ath_softc *sc, struct ath_buf *bf,
Expand Down Expand Up @@ -2125,7 +2157,7 @@ static void ath_tx_processq(struct ath_softc *sc, struct ath_txq *txq)
txq->axq_qnum, ath9k_hw_gettxbuf(sc->sc_ah, txq->axq_qnum),
txq->axq_link);

spin_lock_bh(&txq->axq_lock);
ath_txq_lock(sc, txq);
for (;;) {
if (work_pending(&sc->hw_reset_work))
break;
Expand Down Expand Up @@ -2184,7 +2216,7 @@ static void ath_tx_processq(struct ath_softc *sc, struct ath_txq *txq)

ath_tx_process_buffer(sc, txq, &ts, bf, &bf_head);
}
spin_unlock_bh(&txq->axq_lock);
ath_txq_unlock_complete(sc, txq);
}

static void ath_tx_complete_poll_work(struct work_struct *work)
Expand All @@ -2201,17 +2233,17 @@ static void ath_tx_complete_poll_work(struct work_struct *work)
for (i = 0; i < ATH9K_NUM_TX_QUEUES; i++)
if (ATH_TXQ_SETUP(sc, i)) {
txq = &sc->tx.txq[i];
spin_lock_bh(&txq->axq_lock);
ath_txq_lock(sc, txq);
if (txq->axq_depth) {
if (txq->axq_tx_inprogress) {
needreset = true;
spin_unlock_bh(&txq->axq_lock);
ath_txq_unlock(sc, txq);
break;
} else {
txq->axq_tx_inprogress = true;
}
}
spin_unlock_bh(&txq->axq_lock);
ath_txq_unlock_complete(sc, txq);
}

if (needreset) {
Expand Down Expand Up @@ -2268,10 +2300,10 @@ void ath_tx_edma_tasklet(struct ath_softc *sc)

txq = &sc->tx.txq[ts.qid];

spin_lock_bh(&txq->axq_lock);
ath_txq_lock(sc, txq);

if (list_empty(&txq->txq_fifo[txq->txq_tailidx])) {
spin_unlock_bh(&txq->axq_lock);
ath_txq_unlock(sc, txq);
return;
}

Expand All @@ -2297,7 +2329,7 @@ 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);
ath_txq_unlock_complete(sc, txq);
}
}

Expand Down Expand Up @@ -2435,7 +2467,7 @@ void ath_tx_node_cleanup(struct ath_softc *sc, struct ath_node *an)
ac = tid->ac;
txq = ac->txq;

spin_lock_bh(&txq->axq_lock);
ath_txq_lock(sc, txq);

if (tid->sched) {
list_del(&tid->list);
Expand All @@ -2451,6 +2483,6 @@ void ath_tx_node_cleanup(struct ath_softc *sc, struct ath_node *an)
tid->state &= ~AGGR_ADDBA_COMPLETE;
tid->state &= ~AGGR_CLEANUP;

spin_unlock_bh(&txq->axq_lock);
ath_txq_unlock(sc, txq);
}
}

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