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authorLorenzo Bianconi <lorenzo.bianconi83@gmail.com>2010-08-01 15:47:32 +0200
committerJohn W. Linville <linville@tuxdriver.com>2010-08-04 15:27:38 -0400
commit754018494216e07f43c611d342d7d8bd25b22140 (patch)
treec8918b551fe0a793a3f98ae54415f45f9062e831 /drivers/net
parent824b185adf86163e57892f22a878f97bc4bc69ab (diff)
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ath9k: fix an issue in ath_atx_tid paused flag management
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@gmail.com> Signed-off-by: Felix Fietkau <nbd@openwrt.org> Signed-off-by: John W. Linville <linville@tuxdriver.com>
Diffstat (limited to 'drivers/net')
-rw-r--r--drivers/net/wireless/ath/ath9k/xmit.c34
1 files changed, 8 insertions, 26 deletions
diff --git a/drivers/net/wireless/ath/ath9k/xmit.c b/drivers/net/wireless/ath/ath9k/xmit.c
index 700ba8d..4dda14e 100644
--- 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_txq *txq, struct ath_atx_tid *tid)
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_softc *sc, struct ath_atx_tid *tid)
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 *sc, struct ieee80211_sta *sta,
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 *sc, struct ieee80211_sta *sta, u16 tid)
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)) {