ath9k: rework tx queue selection and fix queue stopping/waking

The current ath9k tx queue handling code showed a few issues that could
lead to locking issues, tx stalls due to stopped queues, and maybe even
DMA issues.

The main source of these issues is that in some places the queue is
selected via skb queue mapping in places where this mapping may no
longer be valid. One such place is when data frames are transmitted via
the CAB queue (for powersave buffered frames). This is made even worse
by a lookup WMM AC values from the assigned tx queue (which is
undefined for the CAB queue).

This messed up the pending frame counting, which in turn caused issues
with queues getting stopped, but not woken again.

To fix these issues, this patch removes an unnecessary abstraction
separating a driver internal queue number from the skb queue number
(not to be confused with the hardware queue number).

It seems that this abstraction may have been necessary because of tx
queue preinitialization from the initvals. This patch avoids breakage
here by pushing the software <-> hardware queue mapping to the function
that assigns the tx queues and redefining the WMM AC definitions to
match the numbers used by mac80211 (also affects ath9k_htc).

To ensure consistency wrt. pending frame count tracking, these counters
are moved to the ath_txq struct, updated with the txq lock held, but
only where the tx queue selected by the skb queue map actually matches
the tx queue used by the driver for the frame.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Reported-by: Björn Smedman <bjorn.smedman@venatech.se>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 10 insertions, 61 deletions

diff --git a/drivers/net/wireless/ath/ath9k/main.c b/drivers/net/wireless/ath/ath9k/main.c
index d522112cf736..df7c62d9bec4 100644
--- a/drivers/net/wireless/ath/ath9k/main.c
+++ b/drivers/net/wireless/ath/ath9k/main.c
@@ -330,7 +330,7 @@ void ath_paprd_calibrate(struct work_struct *work)
         struct ath_tx_control txctl;
         struct ath9k_hw_cal_data *caldata = ah->caldata;
         struct ath_common *common = ath9k_hw_common(ah);
-        int qnum, ftype;
+        int ftype;
         int chain_ok = 0;
         int chain;
         int len = 1800;
@@ -357,8 +357,7 @@ void ath_paprd_calibrate(struct work_struct *work)
         memcpy(hdr->addr3, hw->wiphy->perm_addr, ETH_ALEN);
 
         memset(&txctl, 0, sizeof(txctl));
-        qnum = sc->tx.hwq_map[WME_AC_BE];
-        txctl.txq = &sc->tx.txq[qnum];
+        txctl.txq = sc->tx.txq_map[WME_AC_BE];
 
         ath9k_ps_wakeup(sc);
         ar9003_paprd_init_table(ah);
@@ -1024,56 +1023,6 @@ int ath_reset(struct ath_softc *sc, bool retry_tx)
         return r;
 }
 
-static int ath_get_hal_qnum(u16 queue, struct ath_softc *sc)
-{
-        int qnum;
-
-        switch (queue) {
-        case 0:
-                qnum = sc->tx.hwq_map[WME_AC_VO];
-                break;
-        case 1:
-                qnum = sc->tx.hwq_map[WME_AC_VI];
-                break;
-        case 2:
-                qnum = sc->tx.hwq_map[WME_AC_BE];
-                break;
-        case 3:
-                qnum = sc->tx.hwq_map[WME_AC_BK];
-                break;
-        default:
-                qnum = sc->tx.hwq_map[WME_AC_BE];
-                break;
-        }
-
-        return qnum;
-}
-
-int ath_get_mac80211_qnum(u32 queue, struct ath_softc *sc)
-{
-        int qnum;
-
-        switch (queue) {
-        case WME_AC_VO:
-                qnum = 0;
-                break;
-        case WME_AC_VI:
-                qnum = 1;
-                break;
-        case WME_AC_BE:
-                qnum = 2;
-                break;
-        case WME_AC_BK:
-                qnum = 3;
-                break;
-        default:
-                qnum = -1;
-                break;
-        }
-
-        return qnum;
-}
-
 /* XXX: Remove me once we don't depend on ath9k_channel for all
  * this redundant data */
 void ath9k_update_ichannel(struct ath_softc *sc, struct ieee80211_hw *hw,
@@ -1243,7 +1192,6 @@ static int ath9k_tx(struct ieee80211_hw *hw,
         struct ath_tx_control txctl;
         int padpos, padsize;
         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
-        int qnum;
 
         if (aphy->state != ATH_WIPHY_ACTIVE && aphy->state != ATH_WIPHY_SCAN) {
                 ath_print(common, ATH_DBG_XMIT,
@@ -1316,8 +1264,7 @@ static int ath9k_tx(struct ieee80211_hw *hw,
                 memmove(skb->data, skb->data + padsize, padpos);
         }
 
-        qnum = ath_get_hal_qnum(skb_get_queue_mapping(skb), sc);
-        txctl.txq = &sc->tx.txq[qnum];
+        txctl.txq = sc->tx.txq_map[skb_get_queue_mapping(skb)];
 
         ath_print(common, ATH_DBG_XMIT, "transmitting packet, skb: %p\n", skb);
 
@@ -1801,12 +1748,15 @@ static int ath9k_conf_tx(struct ieee80211_hw *hw, u16 queue,
         struct ath_wiphy *aphy = hw->priv;
         struct ath_softc *sc = aphy->sc;
         struct ath_common *common = ath9k_hw_common(sc->sc_ah);
+        struct ath_txq *txq;
         struct ath9k_tx_queue_info qi;
-        int ret = 0, qnum;
+        int ret = 0;
 
         if (queue >= WME_NUM_AC)
                 return 0;
 
+        txq = sc->tx.txq_map[queue];
+
         mutex_lock(&sc->mutex);
 
         memset(&qi, 0, sizeof(struct ath9k_tx_queue_info));
@@ -1815,20 +1765,19 @@ static int ath9k_conf_tx(struct ieee80211_hw *hw, u16 queue,
         qi.tqi_cwmin = params->cw_min;
         qi.tqi_cwmax = params->cw_max;
         qi.tqi_burstTime = params->txop;
-        qnum = ath_get_hal_qnum(queue, sc);
 
         ath_print(common, ATH_DBG_CONFIG,
                   "Configure tx [queue/halq] [%d/%d],  "
                   "aifs: %d, cw_min: %d, cw_max: %d, txop: %d\n",
-                  queue, qnum, params->aifs, params->cw_min,
+                  queue, txq->axq_qnum, params->aifs, params->cw_min,
                   params->cw_max, params->txop);
 
-        ret = ath_txq_update(sc, qnum, &qi);
+        ret = ath_txq_update(sc, txq->axq_qnum, &qi);
         if (ret)
                 ath_print(common, ATH_DBG_FATAL, "TXQ Update failed\n");
 
         if (sc->sc_ah->opmode == NL80211_IFTYPE_ADHOC)
-                if ((qnum == sc->tx.hwq_map[WME_AC_BE]) && !ret)
+                if (queue == WME_AC_BE && !ret)
                         ath_beaconq_config(sc);
 
         mutex_unlock(&sc->mutex);