rt2x00: Properly reserve room for descriptors in skbs.

Instead of fiddling with the skb->data pointer and thereby risking
out of bounds accesses, properly reserve the space needed in an
skb for descriptors.

Signed-off-by: Gertjan van Wingerde <gwingerde@gmail.com>
Acked-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>

1 files changed, 40 insertions, 0 deletions

diff --git a/drivers/net/wireless/rt2x00/rt2x00pci.c b/drivers/net/wireless/rt2x00/rt2x00pci.c
index 494b960e811c..d583ee070b47 100644
--- a/drivers/net/wireless/rt2x00/rt2x00pci.c
+++ b/drivers/net/wireless/rt2x00/rt2x00pci.c
@@ -82,11 +82,23 @@ int rt2x00pci_write_tx_data(struct queue_entry *entry,
 	}
 
 	/*
+	 * Add the requested extra tx headroom in front of the skb.
+	 */
+	skb_push(entry->skb, rt2x00dev->ops->extra_tx_headroom);
+	memset(entry->skb->data, 0, rt2x00dev->ops->extra_tx_headroom);
+
+	/*
 	 * Call the driver's write_tx_datadesc function, if it exists.
 	 */
 	if (rt2x00dev->ops->lib->write_tx_datadesc)
 		rt2x00dev->ops->lib->write_tx_datadesc(entry, txdesc);
 
+	/*
+	 * Map the skb to DMA.
+	 */
+	if (test_bit(DRIVER_REQUIRE_DMA, &rt2x00dev->flags))
+		rt2x00queue_map_txskb(rt2x00dev, entry->skb);
+
 	return 0;
 }
 EXPORT_SYMBOL_GPL(rt2x00pci_write_tx_data);
@@ -94,6 +106,34 @@ EXPORT_SYMBOL_GPL(rt2x00pci_write_tx_data);
 /*
  * TX/RX data handlers.
  */
+void rt2x00pci_txdone(struct queue_entry *entry,
+		      struct txdone_entry_desc *txdesc)
+{
+	struct rt2x00_dev *rt2x00dev = entry->queue->rt2x00dev;
+	struct skb_frame_desc *skbdesc = get_skb_frame_desc(entry->skb);
+
+	/*
+	 * Unmap the skb.
+	 */
+	rt2x00queue_unmap_skb(rt2x00dev, entry->skb);
+
+	/*
+	 * Remove the extra tx headroom from the skb.
+	 */
+	skb_pull(entry->skb, rt2x00dev->ops->extra_tx_headroom);
+
+	/*
+	 * Signal that the TX descriptor is no longer in the skb.
+	 */
+	skbdesc->flags &= ~SKBDESC_DESC_IN_SKB;
+
+	/*
+	 * Pass on to rt2x00lib.
+	 */
+	rt2x00lib_txdone(entry, txdesc);
+}
+EXPORT_SYMBOL_GPL(rt2x00pci_txdone);
+
 void rt2x00pci_rxdone(struct rt2x00_dev *rt2x00dev)
 {
 	struct data_queue *queue = rt2x00dev->rx;