ath9k: Synchronize DMA transfer with CPU at right place

This patch does pci_dma_sync_single_for_cpu() before accessing
the header of the frame and queueing the same buffer into h/w.

Signed-off-by: Vasanthakumar Thiagarajan <vasanth@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/drivers/net/wireless/ath9k/recv.c b/drivers/net/wireless/ath9k/recv.c
index cc160fe..462e08c 100644 (file)
--- a/drivers/net/wireless/ath9k/recv.c
+++ b/drivers/net/wireless/ath9k/recv.c
@@ -519,6 +519,15 @@ int ath_rx_tasklet(struct ath_softc *sc, int flush)
                if (!skb)
                        continue;
 
+               /*
+                * Synchronize the DMA transfer with CPU before
+                * 1. accessing the frame
+                * 2. requeueing the same buffer to h/w
+                */
+               pci_dma_sync_single_for_cpu(sc->pdev, bf->bf_buf_addr,
+                               sc->rx.bufsize,
+                               PCI_DMA_FROMDEVICE);
+
                /*
                 * If we're asked to flush receive queue, directly
                 * chain it back at the queue without processing it.
@@ -547,10 +556,7 @@ int ath_rx_tasklet(struct ath_softc *sc, int flush)
                if (!requeue_skb)
                        goto requeue;
 
-               /* Sync and unmap the frame */
-               pci_dma_sync_single_for_cpu(sc->pdev, bf->bf_buf_addr,
-                                           sc->rx.bufsize,
-                                           PCI_DMA_FROMDEVICE);
+               /* Unmap the frame */
                pci_unmap_single(sc->pdev, bf->bf_buf_addr,
                                 sc->rx.bufsize,
                                 PCI_DMA_FROMDEVICE);