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>

diff --git a/drivers/net/wireless/p54/p54pci.c b/drivers/net/wireless/p54/p54pci.c
index 1eacba4..0494d7b 100644 (file)
--- 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);
                }