ath9k_htc: Fix TX queue management

Handle queue start/stop properly by maintaining
a counter to check if the pending frame count has
exceeded the threshold. Otherwise, packets would be
dropped needlessly. While at it, use a simple flag
to track queue status and use helper functions too.

Signed-off-by: Sujith Manoharan <Sujith.Manoharan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/drivers/net/wireless/ath/ath9k/htc.h b/drivers/net/wireless/ath/ath9k/htc.h
index 3185fe7..fc4c466 100644 (file)
--- a/drivers/net/wireless/ath/ath9k/htc.h
+++ b/drivers/net/wireless/ath/ath9k/htc.h
@@ -262,11 +262,16 @@ struct ath9k_htc_rx {
        spinlock_t rxbuflock;
 };
 
-struct ath9k_htc_tx {
-       bool tx_queues_stop;
-       spinlock_t tx_lock;
+#define ATH9K_HTC_TX_RESERVE   10
+#define ATH9K_HTC_TX_THRESHOLD (MAX_TX_BUF_NUM - ATH9K_HTC_TX_RESERVE)
+
+#define ATH9K_HTC_OP_TX_QUEUES_STOP BIT(0)
 
+struct ath9k_htc_tx {
+       u8 flags;
+       int queued_cnt;
        struct sk_buff_head tx_queue;
+       spinlock_t tx_lock;
 };
 
 struct ath9k_htc_tx_ctl {
@@ -532,6 +537,8 @@ int ath9k_htc_cabq_setup(struct ath9k_htc_priv *priv);
 int get_hw_qnum(u16 queue, int *hwq_map);
 int ath_htc_txq_update(struct ath9k_htc_priv *priv, int qnum,
                       struct ath9k_tx_queue_info *qinfo);
+void ath9k_htc_check_stop_queues(struct ath9k_htc_priv *priv);
+void ath9k_htc_check_wake_queues(struct ath9k_htc_priv *priv);
 
 int ath9k_rx_init(struct ath9k_htc_priv *priv);
 void ath9k_rx_cleanup(struct ath9k_htc_priv *priv);

diff --git a/drivers/net/wireless/ath/ath9k/htc_drv_beacon.c b/drivers/net/wireless/ath/ath9k/htc_drv_beacon.c
index 713def1..de37d46 100644 (file)
--- a/drivers/net/wireless/ath/ath9k/htc_drv_beacon.c
+++ b/drivers/net/wireless/ath/ath9k/htc_drv_beacon.c
@@ -326,6 +326,10 @@ static void ath9k_htc_send_buffered(struct ath9k_htc_priv *priv,
                        ath_dbg(common, ATH_DBG_FATAL,
                                "Failed to send CAB frame\n");
                        dev_kfree_skb_any(skb);
+               } else {
+                       spin_lock_bh(&priv->tx.tx_lock);
+                       priv->tx.queued_cnt++;
+                       spin_unlock_bh(&priv->tx.tx_lock);
                }
        next:
                skb = ieee80211_get_buffered_bc(priv->hw, vif);

diff --git a/drivers/net/wireless/ath/ath9k/htc_drv_gpio.c b/drivers/net/wireless/ath/ath9k/htc_drv_gpio.c
index 1f6df4a..92e4b31 100644 (file)
--- a/drivers/net/wireless/ath/ath9k/htc_drv_gpio.c
+++ b/drivers/net/wireless/ath/ath9k/htc_drv_gpio.c
@@ -399,7 +399,7 @@ void ath9k_htc_radio_enable(struct ieee80211_hw *hw)
        /* Start TX */
        htc_start(priv->htc);
        spin_lock_bh(&priv->tx.tx_lock);
-       priv->tx.tx_queues_stop = false;
+       priv->tx.flags &= ~ATH9K_HTC_OP_TX_QUEUES_STOP;
        spin_unlock_bh(&priv->tx.tx_lock);
        ieee80211_wake_queues(hw);
 

diff --git a/drivers/net/wireless/ath/ath9k/htc_drv_main.c b/drivers/net/wireless/ath/ath9k/htc_drv_main.c
index ff3a495..6901136 100644 (file)
--- a/drivers/net/wireless/ath/ath9k/htc_drv_main.c
+++ b/drivers/net/wireless/ath/ath9k/htc_drv_main.c
@@ -833,6 +833,7 @@ static void ath9k_htc_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
 {
        struct ieee80211_hdr *hdr;
        struct ath9k_htc_priv *priv = hw->priv;
+       struct ath_common *common = ath9k_hw_common(priv->ah);
        int padpos, padsize, ret;
 
        hdr = (struct ieee80211_hdr *) skb->data;
@@ -841,28 +842,22 @@ static void ath9k_htc_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
        padpos = ath9k_cmn_padpos(hdr->frame_control);
        padsize = padpos & 3;
        if (padsize && skb->len > padpos) {
-               if (skb_headroom(skb) < padsize)
+               if (skb_headroom(skb) < padsize) {
+                       ath_dbg(common, ATH_DBG_XMIT, "No room for padding\n");
                        goto fail_tx;
+               }
                skb_push(skb, padsize);
                memmove(skb->data, skb->data + padsize, padpos);
        }
 
        ret = ath9k_htc_tx_start(priv, skb, false);
        if (ret != 0) {
-               if (ret == -ENOMEM) {
-                       ath_dbg(ath9k_hw_common(priv->ah), ATH_DBG_XMIT,
-                               "Stopping TX queues\n");
-                       ieee80211_stop_queues(hw);
-                       spin_lock_bh(&priv->tx.tx_lock);
-                       priv->tx.tx_queues_stop = true;
-                       spin_unlock_bh(&priv->tx.tx_lock);
-               } else {
-                       ath_dbg(ath9k_hw_common(priv->ah), ATH_DBG_XMIT,
-                               "Tx failed\n");
-               }
+               ath_dbg(common, ATH_DBG_XMIT, "Tx failed\n");
                goto fail_tx;
        }
 
+       ath9k_htc_check_stop_queues(priv);
+
        return;
 
 fail_tx:
@@ -924,7 +919,7 @@ static int ath9k_htc_start(struct ieee80211_hw *hw)
        htc_start(priv->htc);
 
        spin_lock_bh(&priv->tx.tx_lock);
-       priv->tx.tx_queues_stop = false;
+       priv->tx.flags &= ~ATH9K_HTC_OP_TX_QUEUES_STOP;
        spin_unlock_bh(&priv->tx.tx_lock);
 
        ieee80211_wake_queues(hw);

diff --git a/drivers/net/wireless/ath/ath9k/htc_drv_txrx.c b/drivers/net/wireless/ath/ath9k/htc_drv_txrx.c
index 6f7987d..1cbe194 100644 (file)
--- a/drivers/net/wireless/ath/ath9k/htc_drv_txrx.c
+++ b/drivers/net/wireless/ath/ath9k/htc_drv_txrx.c
@@ -53,6 +53,29 @@ int get_hw_qnum(u16 queue, int *hwq_map)
        }
 }
 
+void ath9k_htc_check_stop_queues(struct ath9k_htc_priv *priv)
+{
+       spin_lock_bh(&priv->tx.tx_lock);
+       priv->tx.queued_cnt++;
+       if ((priv->tx.queued_cnt >= ATH9K_HTC_TX_THRESHOLD) &&
+           !(priv->tx.flags & ATH9K_HTC_OP_TX_QUEUES_STOP)) {
+               priv->tx.flags |= ATH9K_HTC_OP_TX_QUEUES_STOP;
+               ieee80211_stop_queues(priv->hw);
+       }
+       spin_unlock_bh(&priv->tx.tx_lock);
+}
+
+void ath9k_htc_check_wake_queues(struct ath9k_htc_priv *priv)
+{
+       spin_lock_bh(&priv->tx.tx_lock);
+       if ((priv->tx.queued_cnt < ATH9K_HTC_TX_THRESHOLD) &&
+           (priv->tx.flags & ATH9K_HTC_OP_TX_QUEUES_STOP)) {
+               priv->tx.flags &= ~ATH9K_HTC_OP_TX_QUEUES_STOP;
+               ieee80211_wake_queues(priv->hw);
+       }
+       spin_unlock_bh(&priv->tx.tx_lock);
+}
+
 int ath_htc_txq_update(struct ath9k_htc_priv *priv, int qnum,
                       struct ath9k_tx_queue_info *qinfo)
 {
@@ -302,21 +325,17 @@ void ath9k_tx_tasklet(unsigned long data)
                rcu_read_unlock();
 
        send_mac80211:
+               spin_lock_bh(&priv->tx.tx_lock);
+               if (WARN_ON(--priv->tx.queued_cnt < 0))
+                       priv->tx.queued_cnt = 0;
+               spin_unlock_bh(&priv->tx.tx_lock);
+
                /* Send status to mac80211 */
                ieee80211_tx_status(priv->hw, skb);
        }
 
        /* Wake TX queues if needed */
-       spin_lock_bh(&priv->tx.tx_lock);
-       if (priv->tx.tx_queues_stop) {
-               priv->tx.tx_queues_stop = false;
-               spin_unlock_bh(&priv->tx.tx_lock);
-               ath_dbg(ath9k_hw_common(priv->ah), ATH_DBG_XMIT,
-                       "Waking up TX queues\n");
-               ieee80211_wake_queues(priv->hw);
-               return;
-       }
-       spin_unlock_bh(&priv->tx.tx_lock);
+       ath9k_htc_check_wake_queues(priv);
 }
 
 void ath9k_htc_txep(void *drv_priv, struct sk_buff *skb,