ath9k_htc: Drain pending TX frames properly

When doing a channel set or a reset operation the pending
frames queued up for transmission have to be flushed and
sent to mac80211. Fixing this has to be done in two separate
steps:

  * Flush queued frames and kill the URB TX completion handler.
  * Complete all the frames that in the TX pending queue.

This patch adds proper support for draining and all the callsites
namely, channel change/reset/idle/stop are fixed. A separate queue
is used for handling failed frames.

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

1 files changed, 30 insertions, 1 deletions

diff --git a/drivers/net/wireless/ath/ath9k/htc_drv_txrx.c b/drivers/net/wireless/ath/ath9k/htc_drv_txrx.c
index 944440c84c49..9e0c34b0a794 100644
--- a/drivers/net/wireless/ath/ath9k/htc_drv_txrx.c
+++ b/drivers/net/wireless/ath/ath9k/htc_drv_txrx.c
@@ -423,6 +423,26 @@ send_mac80211:
         ieee80211_tx_status(priv->hw, skb);
 }
 
+void ath9k_htc_tx_drain(struct ath9k_htc_priv *priv)
+{
+        struct sk_buff *skb = NULL;
+
+        /*
+         * Ensure that all pending TX frames are flushed,
+         * and that the TX completion tasklet is killed.
+         */
+        htc_stop(priv->htc);
+        tasklet_kill(&priv->tx_tasklet);
+
+        while ((skb = skb_dequeue(&priv->tx.tx_queue)) != NULL) {
+                ath9k_htc_tx_process(priv, skb);
+        }
+
+        while ((skb = skb_dequeue(&priv->tx.tx_failed)) != NULL) {
+                ath9k_htc_tx_process(priv, skb);
+        }
+}
+
 void ath9k_tx_tasklet(unsigned long data)
 {
         struct ath9k_htc_priv *priv = (struct ath9k_htc_priv *)data;
@@ -432,6 +452,10 @@ void ath9k_tx_tasklet(unsigned long data)
                 ath9k_htc_tx_process(priv, skb);
         }
 
+        while ((skb = skb_dequeue(&priv->tx.tx_failed)) != NULL) {
+                ath9k_htc_tx_process(priv, skb);
+        }
+
         /* Wake TX queues if needed */
         ath9k_htc_check_wake_queues(priv);
 }
@@ -445,13 +469,18 @@ void ath9k_htc_txep(void *drv_priv, struct sk_buff *skb,
         tx_ctl = HTC_SKB_CB(skb);
         tx_ctl->txok = txok;
 
-        skb_queue_tail(&priv->tx.tx_queue, skb);
+        if (txok)
+                skb_queue_tail(&priv->tx.tx_queue, skb);
+        else
+                skb_queue_tail(&priv->tx.tx_failed, skb);
+
         tasklet_schedule(&priv->tx_tasklet);
 }
 
 int ath9k_tx_init(struct ath9k_htc_priv *priv)
 {
         skb_queue_head_init(&priv->tx.tx_queue);
+        skb_queue_head_init(&priv->tx.tx_failed);
         return 0;
 }