rt2x00: Always call ieee80211_stop_queue() when return NETDEV_TX_BUSY

Apparently it was possible that ieee80211_stop_queue() was not full while
NETDEV_TX_BUSY was being reported back. I think that is what causing the WARN_ON().
This moves all calls to ieee80211_stop_queue() in rt2x00mac.c where it is easier
to determine if the queue should be halted.
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/rt2x00/rt2x00mac.c

@@ -84,7 +84,7 @@ int rt2x00mac_tx(struct ieee80211_hw *hw, struct sk_buff *skb,
 	 */
 	if (!test_bit(DEVICE_PRESENT, &rt2x00dev->flags)) {
 		ieee80211_stop_queues(hw);
-		return 0;
+		return NETDEV_TX_OK;
 	}
 
 	/*
@@ -110,15 +110,24 @@ int rt2x00mac_tx(struct ieee80211_hw *hw, struct sk_buff *skb,
 	if (!is_rts_frame(frame_control) && !is_cts_frame(frame_control) &&
 	    (control->flags & (IEEE80211_TXCTL_USE_RTS_CTS |
 			       IEEE80211_TXCTL_USE_CTS_PROTECT))) {
-		if (rt2x00_ring_free(ring) <= 1)
+		if (rt2x00_ring_free(ring) <= 1) {
+			ieee80211_stop_queue(rt2x00dev->hw, control->queue);
 			return NETDEV_TX_BUSY;
+		}
 
-		if (rt2x00mac_tx_rts_cts(rt2x00dev, ring, skb, control))
+		if (rt2x00mac_tx_rts_cts(rt2x00dev, ring, skb, control)) {
+			ieee80211_stop_queue(rt2x00dev->hw, control->queue);
 			return NETDEV_TX_BUSY;
+		}
 	}
 
-	if (rt2x00dev->ops->lib->write_tx_data(rt2x00dev, ring, skb, control))
+	if (rt2x00dev->ops->lib->write_tx_data(rt2x00dev, ring, skb, control)) {
+		ieee80211_stop_queue(rt2x00dev->hw, control->queue);
 		return NETDEV_TX_BUSY;
+	}
+
+	if (rt2x00_ring_full(ring))
+		ieee80211_stop_queue(rt2x00dev->hw, control->queue);
 
 	if (rt2x00dev->ops->lib->kick_tx_queue)
 		rt2x00dev->ops->lib->kick_tx_queue(rt2x00dev, control->queue);

drivers/net/wireless/rt2x00/rt2x00pci.c

@@ -86,10 +86,8 @@ int rt2x00pci_write_tx_data(struct rt2x00_dev *rt2x00dev,
 	struct skb_desc *desc;
 	u32 word;
 
-	if (rt2x00_ring_full(ring)) {
-		ieee80211_stop_queue(rt2x00dev->hw, control->queue);
+	if (rt2x00_ring_full(ring))
 		return -EINVAL;
-	}
 
 	rt2x00_desc_read(txd, 0, &word);
 
@@ -99,7 +97,6 @@ int rt2x00pci_write_tx_data(struct rt2x00_dev *rt2x00dev,
 		      "Arrived at non-free entry in the non-full queue %d.\n"
 		      "Please file bug report to %s.\n",
 		      control->queue, DRV_PROJECT);
-		ieee80211_stop_queue(rt2x00dev->hw, control->queue);
 		return -EINVAL;
 	}
 
@@ -119,9 +116,6 @@ int rt2x00pci_write_tx_data(struct rt2x00_dev *rt2x00dev,
 
 	rt2x00_ring_index_inc(ring);
 
-	if (rt2x00_ring_full(ring))
-		ieee80211_stop_queue(rt2x00dev->hw, control->queue);
-
 	return 0;
 }
 EXPORT_SYMBOL_GPL(rt2x00pci_write_tx_data);

drivers/net/wireless/rt2x00/rt2x00usb.c

@@ -179,17 +179,14 @@ int rt2x00usb_write_tx_data(struct rt2x00_dev *rt2x00dev,
 	struct skb_desc *desc;
 	u32 length;
 
-	if (rt2x00_ring_full(ring)) {
-		ieee80211_stop_queue(rt2x00dev->hw, control->queue);
+	if (rt2x00_ring_full(ring))
 		return -EINVAL;
-	}
 
 	if (test_bit(ENTRY_OWNER_NIC, &entry->flags)) {
 		ERROR(rt2x00dev,
 		      "Arrived at non-free entry in the non-full queue %d.\n"
 		      "Please file bug report to %s.\n",
 		      control->queue, DRV_PROJECT);
-		ieee80211_stop_queue(rt2x00dev->hw, control->queue);
 		return -EINVAL;
 	}
 
@@ -229,9 +226,6 @@ int rt2x00usb_write_tx_data(struct rt2x00_dev *rt2x00dev,
 
 	rt2x00_ring_index_inc(ring);
 
-	if (rt2x00_ring_full(ring))
-		ieee80211_stop_queue(rt2x00dev->hw, control->queue);
-
 	return 0;
 }
 EXPORT_SYMBOL_GPL(rt2x00usb_write_tx_data);