ixgbe: Fix DMA mapping/unmapping issues when HWRSC is enabled on IOMMU enabled kernels
authorMallikarjuna R Chilakala <mallikarjuna.chilakala@intel.com>
Thu, 25 Feb 2010 23:14:37 +0000 (23:14 +0000)
committerDavid S. Miller <davem@davemloft.net>
Fri, 26 Feb 2010 10:10:10 +0000 (02:10 -0800)
Work around 82599 HW issue when HWRSC is enabled on IOMMU enabled
kernels. 82599 HW is updating the header information after setting the
descriptor to done, resulting DMA mapping/unmapping issues on IOMMU
enabled systems. To work around the issue delay unmapping of first packet
that carries the header information until end of packet is reached.

Signed-off-by: Mallikarjuna R Chilakala <mallikarjuna.chilakala@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
drivers/net/ixgbe/ixgbe_main.c

index 330879004ea1be1c08575330b6ff9ea9c67a4d0e..4a0102218d39d73db3d70dee008e239299ee29fc 100644 (file)
@@ -818,6 +818,12 @@ static inline struct sk_buff *ixgbe_transform_rsc_queue(struct sk_buff *skb,
        return skb;
 }
 
+struct ixgbe_rsc_cb {
+       dma_addr_t dma;
+};
+
+#define IXGBE_RSC_CB(skb) ((struct ixgbe_rsc_cb *)(skb)->cb)
+
 static bool ixgbe_clean_rx_irq(struct ixgbe_q_vector *q_vector,
                                struct ixgbe_ring *rx_ring,
                                int *work_done, int work_to_do)
@@ -867,9 +873,21 @@ static bool ixgbe_clean_rx_irq(struct ixgbe_q_vector *q_vector,
                rx_buffer_info->skb = NULL;
 
                if (rx_buffer_info->dma) {
-                       pci_unmap_single(pdev, rx_buffer_info->dma,
-                                        rx_ring->rx_buf_len,
-                                        PCI_DMA_FROMDEVICE);
+                       if ((adapter->flags2 & IXGBE_FLAG2_RSC_ENABLED) &&
+                           (!(staterr & IXGBE_RXD_STAT_EOP)) &&
+                                (!(skb->prev)))
+                               /*
+                                * When HWRSC is enabled, delay unmapping
+                                * of the first packet. It carries the
+                                * header information, HW may still
+                                * access the header after the writeback.
+                                * Only unmap it when EOP is reached
+                                */
+                               IXGBE_RSC_CB(skb)->dma = rx_buffer_info->dma;
+                       else
+                               pci_unmap_single(pdev, rx_buffer_info->dma,
+                                                rx_ring->rx_buf_len,
+                                                PCI_DMA_FROMDEVICE);
                        rx_buffer_info->dma = 0;
                        skb_put(skb, len);
                }
@@ -917,6 +935,10 @@ static bool ixgbe_clean_rx_irq(struct ixgbe_q_vector *q_vector,
                        if (skb->prev)
                                skb = ixgbe_transform_rsc_queue(skb, &(rx_ring->rsc_count));
                        if (adapter->flags2 & IXGBE_FLAG2_RSC_ENABLED) {
+                               if (IXGBE_RSC_CB(skb)->dma)
+                                       pci_unmap_single(pdev, IXGBE_RSC_CB(skb)->dma,
+                                                        rx_ring->rx_buf_len,
+                                                        PCI_DMA_FROMDEVICE);
                                if (rx_ring->flags & IXGBE_RING_RX_PS_ENABLED)
                                        rx_ring->rsc_count += skb_shinfo(skb)->nr_frags;
                                else
@@ -3104,6 +3126,10 @@ static void ixgbe_clean_rx_ring(struct ixgbe_adapter *adapter,
                        rx_buffer_info->skb = NULL;
                        do {
                                struct sk_buff *this = skb;
+                               if (IXGBE_RSC_CB(this)->dma)
+                                       pci_unmap_single(pdev, IXGBE_RSC_CB(this)->dma,
+                                                        rx_ring->rx_buf_len,
+                                                        PCI_DMA_FROMDEVICE);
                                skb = skb->prev;
                                dev_kfree_skb(this);
                        } while (skb);