rt2x00: Don't kick TX queue after each frame

TX queues shouldn't be kicked after each frame that is put into the
queue.  This could cause problems during RTS and CTS-to-self as well
as with fragmentation. In all those cases you want all frames to be
send out in a single burst. Off course we shouldn't let the queue fill
up entirely, thus we introduce a 10% threshold which, when reached,
will force the frames to be send out regardless of the frame.

In addition we should prevent queues to become full in such a way
that the tx() handler can fail. Instead of stopping the queue when
it is full, we should stop it when it is below the threshold.

Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

11 files changed, 39 insertions, 37 deletions

diff --git a/drivers/net/wireless/rt2x00/rt2400pci.c b/drivers/net/wireless/rt2x00/rt2400pci.c
index 94226b47d1d9..b5b0ded83e0f 100644
--- a/drivers/net/wireless/rt2x00/rt2400pci.c
+++ b/drivers/net/wireless/rt2x00/rt2400pci.c
@@ -1507,7 +1507,6 @@ static int rt2400pci_beacon_update(struct ieee80211_hw *hw, struct sk_buff *skb)
          */
         skbdesc = get_skb_frame_desc(skb);
         memset(skbdesc, 0, sizeof(*skbdesc));
-        skbdesc->flags |= FRAME_DESC_DRIVER_GENERATED;
         skbdesc->data = skb->data;
         skbdesc->data_len = skb->len;
         skbdesc->desc = entry_priv->desc;
diff --git a/drivers/net/wireless/rt2x00/rt2500pci.c b/drivers/net/wireless/rt2x00/rt2500pci.c
index c8cf8c1d095f..74b54c948b8d 100644
--- a/drivers/net/wireless/rt2x00/rt2500pci.c
+++ b/drivers/net/wireless/rt2x00/rt2500pci.c
@@ -1823,7 +1823,6 @@ static int rt2500pci_beacon_update(struct ieee80211_hw *hw, struct sk_buff *skb)
          */
         skbdesc = get_skb_frame_desc(skb);
         memset(skbdesc, 0, sizeof(*skbdesc));
-        skbdesc->flags |= FRAME_DESC_DRIVER_GENERATED;
         skbdesc->data = skb->data;
         skbdesc->data_len = skb->len;
         skbdesc->desc = entry_priv->desc;
diff --git a/drivers/net/wireless/rt2x00/rt2500usb.c b/drivers/net/wireless/rt2x00/rt2500usb.c
index 6abb4c5338f5..076221413db7 100644
--- a/drivers/net/wireless/rt2x00/rt2500usb.c
+++ b/drivers/net/wireless/rt2x00/rt2500usb.c
@@ -1711,7 +1711,6 @@ static int rt2500usb_beacon_update(struct ieee80211_hw *hw, struct sk_buff *skb)
          */
         skbdesc = get_skb_frame_desc(skb);
         memset(skbdesc, 0, sizeof(*skbdesc));
-        skbdesc->flags |= FRAME_DESC_DRIVER_GENERATED;
         skbdesc->data = skb->data + intf->beacon->queue->desc_size;
         skbdesc->data_len = skb->len - intf->beacon->queue->desc_size;
         skbdesc->desc = skb->data;
diff --git a/drivers/net/wireless/rt2x00/rt2x00.h b/drivers/net/wireless/rt2x00/rt2x00.h
index c7da3c25237e..938d375027be 100644
--- a/drivers/net/wireless/rt2x00/rt2x00.h
+++ b/drivers/net/wireless/rt2x00/rt2x00.h
@@ -826,7 +826,7 @@ struct rt2x00_dev {
          * The Beacon array also contains the Atim queue
          * if that is supported by the device.
          */
-        int data_queues;
+        unsigned int data_queues;
         struct data_queue *rx;
         struct data_queue *tx;
         struct data_queue *bcn;
diff --git a/drivers/net/wireless/rt2x00/rt2x00mac.c b/drivers/net/wireless/rt2x00/rt2x00mac.c
index e7f544c404bc..59f273bf5b5e 100644
--- a/drivers/net/wireless/rt2x00/rt2x00mac.c
+++ b/drivers/net/wireless/rt2x00/rt2x00mac.c
@@ -34,7 +34,6 @@ static int rt2x00mac_tx_rts_cts(struct rt2x00_dev *rt2x00dev,
                                 struct sk_buff *frag_skb)
 {
         struct ieee80211_tx_info *tx_info = IEEE80211_SKB_CB(frag_skb);
-        struct skb_frame_desc *skbdesc;
         struct ieee80211_tx_info *rts_info;
         struct sk_buff *skb;
         int size;
@@ -82,13 +81,6 @@ static int rt2x00mac_tx_rts_cts(struct rt2x00_dev *rt2x00dev,
                                   frag_skb->data, size, tx_info,
                                   (struct ieee80211_rts *)(skb->data));
 
-        /*
-         * Initialize skb descriptor
-         */
-        skbdesc = get_skb_frame_desc(skb);
-        memset(skbdesc, 0, sizeof(*skbdesc));
-        skbdesc->flags |= FRAME_DESC_DRIVER_GENERATED;
-
         if (rt2x00queue_write_tx_frame(queue, skb)) {
                 WARNING(rt2x00dev, "Failed to send RTS/CTS frame.\n");
                 return NETDEV_TX_BUSY;
@@ -163,7 +155,7 @@ int rt2x00mac_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
                 return NETDEV_TX_BUSY;
         }
 
-        if (rt2x00queue_full(queue))
+        if (rt2x00queue_threshold(queue))
                 ieee80211_stop_queue(rt2x00dev->hw, qid);
 
         return NETDEV_TX_OK;
diff --git a/drivers/net/wireless/rt2x00/rt2x00pci.c b/drivers/net/wireless/rt2x00/rt2x00pci.c
index a6bac75de9f2..9745277c81ce 100644
--- a/drivers/net/wireless/rt2x00/rt2x00pci.c
+++ b/drivers/net/wireless/rt2x00/rt2x00pci.c
@@ -170,11 +170,11 @@ void rt2x00pci_txdone(struct rt2x00_dev *rt2x00dev, struct queue_entry *entry,
         rt2x00queue_index_inc(entry->queue, Q_INDEX_DONE);
 
         /*
-         * If the data queue was full before the txdone handler
-         * we must make sure the packet queue in the mac80211 stack
+         * If the data queue was below the threshold before the txdone
+         * handler we must make sure the packet queue in the mac80211 stack
          * is reenabled when the txdone handler has finished.
          */
-        if (!rt2x00queue_full(entry->queue))
+        if (!rt2x00queue_threshold(entry->queue))
                 ieee80211_wake_queue(rt2x00dev->hw, qid);
 
 }
diff --git a/drivers/net/wireless/rt2x00/rt2x00queue.c b/drivers/net/wireless/rt2x00/rt2x00queue.c
index f875b7ab09fe..493066519ef3 100644
--- a/drivers/net/wireless/rt2x00/rt2x00queue.c
+++ b/drivers/net/wireless/rt2x00/rt2x00queue.c
@@ -163,8 +163,8 @@ EXPORT_SYMBOL_GPL(rt2x00queue_create_tx_descriptor);
 void rt2x00queue_write_tx_descriptor(struct queue_entry *entry,
                                      struct txentry_desc *txdesc)
 {
-        struct rt2x00_dev *rt2x00dev = entry->queue->rt2x00dev;
-        struct skb_frame_desc *skbdesc = get_skb_frame_desc(entry->skb);
+        struct data_queue *queue = entry->queue;
+        struct rt2x00_dev *rt2x00dev = queue->rt2x00dev;
 
         rt2x00dev->ops->lib->write_tx_desc(rt2x00dev, entry->skb, txdesc);
 
@@ -175,16 +175,21 @@ void rt2x00queue_write_tx_descriptor(struct queue_entry *entry,
         rt2x00debug_dump_frame(rt2x00dev, DUMP_FRAME_TX, entry->skb);
 
         /*
-         * We are done writing the frame to the queue entry,
-         * also kick the queue in case the correct flags are set,
-         * note that this will automatically filter beacons and
-         * RTS/CTS frames since those frames don't have this flag
-         * set.
+         * Check if we need to kick the queue, there are however a few rules
+         *      1) Don't kick beacon queue
+         *      2) Don't kick unless this is the last in frame in a burst.
+         *         When the burst flag is set, this frame is always followed
+         *         by another frame which in some way are related to eachother.
+         *         This is true for fragments, RTS or CTS-to-self frames.
+         *      3) Rule 2 can be broken when the available entries
+         *         in the queue are less then a certain threshold.
          */
-        if (rt2x00dev->ops->lib->kick_tx_queue &&
-            !(skbdesc->flags & FRAME_DESC_DRIVER_GENERATED))
-                rt2x00dev->ops->lib->kick_tx_queue(rt2x00dev,
-                                                   entry->queue->qid);
+        if (entry->queue->qid == QID_BEACON)
+                return;
+
+        if (rt2x00queue_threshold(queue) ||
+            !test_bit(ENTRY_TXD_BURST, &txdesc->flags))
+                rt2x00dev->ops->lib->kick_tx_queue(rt2x00dev, queue->qid);
 }
 EXPORT_SYMBOL_GPL(rt2x00queue_write_tx_descriptor);
 
@@ -349,6 +354,7 @@ static int rt2x00queue_alloc_entries(struct data_queue *queue,
         rt2x00queue_reset(queue);
 
         queue->limit = qdesc->entry_num;
+        queue->threshold = DIV_ROUND_UP(qdesc->entry_num, 10);
         queue->data_size = qdesc->data_size;
         queue->desc_size = qdesc->desc_size;
 
diff --git a/drivers/net/wireless/rt2x00/rt2x00queue.h b/drivers/net/wireless/rt2x00/rt2x00queue.h
index 303d5568470d..623fc27dc7bb 100644
--- a/drivers/net/wireless/rt2x00/rt2x00queue.h
+++ b/drivers/net/wireless/rt2x00/rt2x00queue.h
@@ -82,12 +82,10 @@ enum data_queue_qid {
 /**
  * enum skb_frame_desc_flags: Flags for &struct skb_frame_desc
  *
- * @FRAME_DESC_DRIVER_GENERATED: Frame was generated inside driver
- *      and should not be reported back to mac80211 during txdone.
  */
-enum skb_frame_desc_flags {
-        FRAME_DESC_DRIVER_GENERATED = 1 << 0,
-};
+//enum skb_frame_desc_flags {
+//      TEMPORARILY EMPTY
+//};
 
 /**
  * struct skb_frame_desc: Descriptor information for the skb buffer
@@ -325,6 +323,7 @@ enum queue_index {
  *      index corruption due to concurrency.
  * @count: Number of frames handled in the queue.
  * @limit: Maximum number of entries in the queue.
+ * @threshold: Minimum number of free entries before queue is kicked by force.
  * @length: Number of frames in queue.
  * @index: Index pointers to entry positions in the queue,
  *      use &enum queue_index to get a specific index field.
@@ -343,6 +342,7 @@ struct data_queue {
         spinlock_t lock;
         unsigned int count;
         unsigned short limit;
+        unsigned short threshold;
         unsigned short length;
         unsigned short index[Q_INDEX_MAX];
 
@@ -467,6 +467,15 @@ static inline int rt2x00queue_available(struct data_queue *queue)
 }
 
 /**
+ * rt2x00queue_threshold - Check if the queue is below threshold
+ * @queue: Queue to check.
+ */
+static inline int rt2x00queue_threshold(struct data_queue *queue)
+{
+        return rt2x00queue_available(queue) < queue->threshold;
+}
+
+/**
  * rt2x00_desc_read - Read a word from the hardware descriptor.
  * @desc: Base descriptor address
  * @word: Word index from where the descriptor should be read.
diff --git a/drivers/net/wireless/rt2x00/rt2x00usb.c b/drivers/net/wireless/rt2x00/rt2x00usb.c
index fdf505beb79c..8cf6e3f253e9 100644
--- a/drivers/net/wireless/rt2x00/rt2x00usb.c
+++ b/drivers/net/wireless/rt2x00/rt2x00usb.c
@@ -165,11 +165,11 @@ static void rt2x00usb_interrupt_txdone(struct urb *urb)
         rt2x00queue_index_inc(entry->queue, Q_INDEX_DONE);
 
         /*
-         * If the data queue was full before the txdone handler
-         * we must make sure the packet queue in the mac80211 stack
+         * If the data queue was below the threshold before the txdone
+         * handler we must make sure the packet queue in the mac80211 stack
          * is reenabled when the txdone handler has finished.
          */
-        if (!rt2x00queue_full(entry->queue))
+        if (!rt2x00queue_threshold(entry->queue))
                 ieee80211_wake_queue(rt2x00dev->hw, qid);
 }
 
diff --git a/drivers/net/wireless/rt2x00/rt61pci.c b/drivers/net/wireless/rt2x00/rt61pci.c
index aa9ef66921b8..746f87c8e704 100644
--- a/drivers/net/wireless/rt2x00/rt61pci.c
+++ b/drivers/net/wireless/rt2x00/rt61pci.c
@@ -2375,7 +2375,6 @@ static int rt61pci_beacon_update(struct ieee80211_hw *hw, struct sk_buff *skb)
          */
         skbdesc = get_skb_frame_desc(skb);
         memset(skbdesc, 0, sizeof(*skbdesc));
-        skbdesc->flags |= FRAME_DESC_DRIVER_GENERATED;
         skbdesc->data = skb->data;
         skbdesc->data_len = skb->len;
         skbdesc->desc = entry_priv->desc;
diff --git a/drivers/net/wireless/rt2x00/rt73usb.c b/drivers/net/wireless/rt2x00/rt73usb.c
index 5e5f6034383a..ae50f6332dfa 100644
--- a/drivers/net/wireless/rt2x00/rt73usb.c
+++ b/drivers/net/wireless/rt2x00/rt73usb.c
@@ -1980,7 +1980,6 @@ static int rt73usb_beacon_update(struct ieee80211_hw *hw, struct sk_buff *skb)
          */
         skbdesc = get_skb_frame_desc(skb);
         memset(skbdesc, 0, sizeof(*skbdesc));
-        skbdesc->flags |= FRAME_DESC_DRIVER_GENERATED;
         skbdesc->data = skb->data + intf->beacon->queue->desc_size;
         skbdesc->data_len = skb->len - intf->beacon->queue->desc_size;
         skbdesc->desc = skb->data;