wl1271: Fix queue stopping/waking for TX path

The queue stopping/waking functionality was broken in a way that could
cause huge latencies in TX transfers and even cause the TX to stall in the
right circumstances. Correct these problems.

Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Reviewed-by: Kalle Valo <kalle.valo@nokia.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 5 insertions, 7 deletions

diff --git a/drivers/net/wireless/wl12xx/wl1271_main.c b/drivers/net/wireless/wl12xx/wl1271_main.c
index 81fb02e82923..184264a53b20 100644
--- a/drivers/net/wireless/wl12xx/wl1271_main.c
+++ b/drivers/net/wireless/wl12xx/wl1271_main.c
@@ -791,15 +791,13 @@ static int wl1271_op_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
          * The workqueue is slow to process the tx_queue and we need stop
          * the queue here, otherwise the queue will get too long.
          */
-        if (skb_queue_len(&wl->tx_queue) >= WL1271_TX_QUEUE_MAX_LENGTH) {
-                ieee80211_stop_queues(wl->hw);
+        if (skb_queue_len(&wl->tx_queue) >= WL1271_TX_QUEUE_HIGH_WATERMARK) {
+                wl1271_debug(DEBUG_TX, "op_tx: stopping queues");
 
-                /*
-                 * FIXME: this is racy, the variable is not properly
-                 * protected. Maybe fix this by removing the stupid
-                 * variable altogether and checking the real queue state?
-                 */
+                spin_lock_irqsave(&wl->wl_lock, flags);
+                ieee80211_stop_queues(wl->hw);
                 set_bit(WL1271_FLAG_TX_QUEUE_STOPPED, &wl->flags);
+                spin_unlock_irqrestore(&wl->wl_lock, flags);
         }
 
         return NETDEV_TX_OK;