From: Lorenzo Bianconi <lorenzo.bianconi83@xxxxxxxxx>
I noticed a possible issue in the paused flag management of the
ath_atx_tid data structure. In particular, in a noisy environment and
under heavy load, I observed that the AGGR session establishment could
fail several times consecutively causing values of the paused flag
greater than one for this TID (ath_tx_pause_tid is called more than
once from ath_tx_aggr_start).
Considering that the session for this TID can not be established also
after the mac80211 stack calls the ieee80211_agg_tx_operational() since
the ath_tx_aggr_resume() lowers the paused flag only by one.
This patch also replaces some BUG_ON calls with WARN_ON, as even if
these unlikely conditions happen, it's not fatal enough to justify a
BUG_ON.
Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi83@xxxxxxxxx>
Signed-off-by: Felix Fietkau <nbd@xxxxxxxxxxx>
---
--- a/drivers/net/wireless/ath/ath9k/xmit.c
+++ b/drivers/net/wireless/ath/ath9k/xmit.c
@@ -120,26 +120,14 @@ static void ath_tx_queue_tid(struct ath_
list_add_tail(&ac->list, &txq->axq_acq);
}
-static void ath_tx_pause_tid(struct ath_softc *sc, struct ath_atx_tid *tid)
-{
- struct ath_txq *txq = &sc->tx.txq[tid->ac->qnum];
-
- spin_lock_bh(&txq->axq_lock);
- tid->paused++;
- spin_unlock_bh(&txq->axq_lock);
-}
-
static void ath_tx_resume_tid(struct ath_softc *sc, struct ath_atx_tid *tid)
{
struct ath_txq *txq = &sc->tx.txq[tid->ac->qnum];
- BUG_ON(tid->paused <= 0);
- spin_lock_bh(&txq->axq_lock);
-
- tid->paused--;
+ WARN_ON(!tid->paused);
- if (tid->paused > 0)
- goto unlock;
+ spin_lock_bh(&txq->axq_lock);
+ tid->paused = false;
if (list_empty(&tid->buf_q))
goto unlock;
@@ -157,15 +145,10 @@ static void ath_tx_flush_tid(struct ath_
struct list_head bf_head;
INIT_LIST_HEAD(&bf_head);
- BUG_ON(tid->paused <= 0);
- spin_lock_bh(&txq->axq_lock);
+ WARN_ON(!tid->paused);
- tid->paused--;
-
- if (tid->paused > 0) {
- spin_unlock_bh(&txq->axq_lock);
- return;
- }
+ spin_lock_bh(&txq->axq_lock);
+ tid->paused = false;
while (!list_empty(&tid->buf_q)) {
bf = list_first_entry(&tid->buf_q, struct ath_buf, list);
@@ -811,7 +794,7 @@ void ath_tx_aggr_start(struct ath_softc
an = (struct ath_node *)sta->drv_priv;
txtid = ATH_AN_2_TID(an, tid);
txtid->state |= AGGR_ADDBA_PROGRESS;
- ath_tx_pause_tid(sc, txtid);
+ txtid->paused = true;
*ssn = txtid->seq_start;
}
@@ -835,10 +818,9 @@ void ath_tx_aggr_stop(struct ath_softc *
return;
}
- ath_tx_pause_tid(sc, txtid);
-
/* drop all software retried frames and mark this TID */
spin_lock_bh(&txq->axq_lock);
+ txtid->paused = true;
while (!list_empty(&txtid->buf_q)) {
bf = list_first_entry(&txtid->buf_q, struct ath_buf, list);
if (!bf_isretried(bf)) {
--
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