| Message ID | 1391636287-17712-3-git-send-email-andrea.merello@gmail.com (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
On 02/05/2014 03:38 PM, andrea merello wrote: > From: "andrea.merello" <andrea.merello@gmail.com> > > In original code the old RX DMA buffer is unmapped and processed and at the end > of the isr a new buffer is mapped with pci_map_single and attached to the RX > descriptor. > > If pci_map_single fails then the RX descriptor remains with no valid DMA buffer > attached. > In this condition the DMA will target where it shouldn't with obvious evil > consequences. > > Simply avoiding re-arming the descriptor will prevent buggy DMA but it will > result soon in RX stuck. > > This patch move the DMA mapping of the new buffer at the beginning of the ISR > (and it adds error check for pci_map_single success/fail). > > If the DMA mapping fails then we do not unmap the old buffer and we re-arm the > descriptor without processing it, with the old DMA buffer still attached. > > In this way we lose the currently RX-ed packet, but whenever next calls to > pci_map_single will succeed again,then the RX process will go on without stuck. > > Signed-off-by: andrea.merello <andrea.merello@gmail.com> > Signed-off-by: andrea merello <andrea.merello@gmail.com> I have no way to test this patch, but it looks OK. Larry > --- > drivers/net/wireless/rtl818x/rtl8180/dev.c | 16 +++++++++++++--- > 1 file changed, 13 insertions(+), 3 deletions(-) > > diff --git a/drivers/net/wireless/rtl818x/rtl8180/dev.c b/drivers/net/wireless/rtl818x/rtl8180/dev.c > index 79b9398..1c6ac25 100644 > --- a/drivers/net/wireless/rtl818x/rtl8180/dev.c > +++ b/drivers/net/wireless/rtl818x/rtl8180/dev.c > @@ -107,6 +107,7 @@ static void rtl8180_handle_rx(struct ieee80211_hw *dev) > struct rtl8180_priv *priv = dev->priv; > unsigned int count = 32; > u8 signal, agc, sq; > + dma_addr_t mapping; > > while (count--) { > struct rtl8180_rx_desc *entry = &priv->rx_ring[priv->rx_idx]; > @@ -128,6 +129,17 @@ static void rtl8180_handle_rx(struct ieee80211_hw *dev) > if (unlikely(!new_skb)) > goto done; > > + mapping = pci_map_single(priv->pdev, > + skb_tail_pointer(new_skb), > + MAX_RX_SIZE, PCI_DMA_FROMDEVICE); > + > + if (pci_dma_mapping_error(priv->pdev, mapping)) { > + kfree_skb(new_skb); > + dev_err(&priv->pdev->dev, "RX DMA map error\n"); > + > + goto done; > + } > + > pci_unmap_single(priv->pdev, > *((dma_addr_t *)skb->cb), > MAX_RX_SIZE, PCI_DMA_FROMDEVICE); > @@ -158,9 +170,7 @@ static void rtl8180_handle_rx(struct ieee80211_hw *dev) > > skb = new_skb; > priv->rx_buf[priv->rx_idx] = skb; > - *((dma_addr_t *) skb->cb) = > - pci_map_single(priv->pdev, skb_tail_pointer(skb), > - MAX_RX_SIZE, PCI_DMA_FROMDEVICE); > + *((dma_addr_t *) skb->cb) = mapping; > } > > done: > -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/net/wireless/rtl818x/rtl8180/dev.c b/drivers/net/wireless/rtl818x/rtl8180/dev.c index 79b9398..1c6ac25 100644 --- a/drivers/net/wireless/rtl818x/rtl8180/dev.c +++ b/drivers/net/wireless/rtl818x/rtl8180/dev.c @@ -107,6 +107,7 @@ static void rtl8180_handle_rx(struct ieee80211_hw *dev) struct rtl8180_priv *priv = dev->priv; unsigned int count = 32; u8 signal, agc, sq; + dma_addr_t mapping; while (count--) { struct rtl8180_rx_desc *entry = &priv->rx_ring[priv->rx_idx]; @@ -128,6 +129,17 @@ static void rtl8180_handle_rx(struct ieee80211_hw *dev) if (unlikely(!new_skb)) goto done; + mapping = pci_map_single(priv->pdev, + skb_tail_pointer(new_skb), + MAX_RX_SIZE, PCI_DMA_FROMDEVICE); + + if (pci_dma_mapping_error(priv->pdev, mapping)) { + kfree_skb(new_skb); + dev_err(&priv->pdev->dev, "RX DMA map error\n"); + + goto done; + } + pci_unmap_single(priv->pdev, *((dma_addr_t *)skb->cb), MAX_RX_SIZE, PCI_DMA_FROMDEVICE); @@ -158,9 +170,7 @@ static void rtl8180_handle_rx(struct ieee80211_hw *dev) skb = new_skb; priv->rx_buf[priv->rx_idx] = skb; - *((dma_addr_t *) skb->cb) = - pci_map_single(priv->pdev, skb_tail_pointer(skb), - MAX_RX_SIZE, PCI_DMA_FROMDEVICE); + *((dma_addr_t *) skb->cb) = mapping; } done: