p54pci: update receive dma buffers before and after processing

Documentation/DMA-API-HOWTO.txt states:

"DMA transfers need to be synced properly in order for
the cpu and device to see the most uptodate and correct
copy of the DMA buffer."

Cc: <stable@kernel.org>
Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 9 insertions, 5 deletions

diff --git a/drivers/net/wireless/p54/p54pci.c b/drivers/net/wireless/p54/p54pci.c
index 1eacba4daa5b..0494d7b102d4 100644
--- a/drivers/net/wireless/p54/p54pci.c
+++ b/drivers/net/wireless/p54/p54pci.c
@@ -199,6 +199,7 @@ static void p54p_check_rx_ring(struct ieee80211_hw *dev, u32 *index,
         while (i != idx) {
                 u16 len;
                 struct sk_buff *skb;
+                dma_addr_t dma_addr;
                 desc = &ring[i];
                 len = le16_to_cpu(desc->len);
                 skb = rx_buf[i];
@@ -216,17 +217,20 @@ static void p54p_check_rx_ring(struct ieee80211_hw *dev, u32 *index,
 
                         len = priv->common.rx_mtu;
                 }
+                dma_addr = le32_to_cpu(desc->host_addr);
+                pci_dma_sync_single_for_cpu(priv->pdev, dma_addr,
+                        priv->common.rx_mtu + 32, PCI_DMA_FROMDEVICE);
                 skb_put(skb, len);
 
                 if (p54_rx(dev, skb)) {
-                        pci_unmap_single(priv->pdev,
-                                         le32_to_cpu(desc->host_addr),
-                                         priv->common.rx_mtu + 32,
-                                         PCI_DMA_FROMDEVICE);
+                        pci_unmap_single(priv->pdev, dma_addr,
+                                priv->common.rx_mtu + 32, PCI_DMA_FROMDEVICE);
                         rx_buf[i] = NULL;
-                        desc->host_addr = 0;
+                        desc->host_addr = cpu_to_le32(0);
                 } else {
                         skb_trim(skb, 0);
+                        pci_dma_sync_single_for_device(priv->pdev, dma_addr,
+                                priv->common.rx_mtu + 32, PCI_DMA_FROMDEVICE);
                         desc->len = cpu_to_le16(priv->common.rx_mtu + 32);
                 }