ixgbe: fix unmap length bug

This patch addresses three WARN_ON statements from DMA-API debug code

ixgbe is mapping more than it unmaps, reduce the length of the map call and
remove the "used once" local variable.

found by Joerg Roedel <joerg.roedel@amd.com> in 2.6.30, so is a candidate
for -stable.

in addition, fix missing ->dma = 0 after unmap to prevent double free with
pci_unmap_single

and lastly, don't unmap (half) pages that aren't mapped.

Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
CC: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 11 insertions, 6 deletions

diff --git a/drivers/net/ixgbe/ixgbe_main.c b/drivers/net/ixgbe/ixgbe_main.c
index fce2ef49b3a7..5588ef493a3d 100644
--- a/drivers/net/ixgbe/ixgbe_main.c
+++ b/drivers/net/ixgbe/ixgbe_main.c
@@ -563,7 +563,6 @@ static void ixgbe_alloc_rx_buffers(struct ixgbe_adapter *adapter,
         union ixgbe_adv_rx_desc *rx_desc;
         struct ixgbe_rx_buffer *bi;
         unsigned int i;
-        unsigned int bufsz = rx_ring->rx_buf_len + NET_IP_ALIGN;
 
         i = rx_ring->next_to_use;
         bi = &rx_ring->rx_buffer_info[i];
@@ -593,7 +592,9 @@ static void ixgbe_alloc_rx_buffers(struct ixgbe_adapter *adapter,
 
                 if (!bi->skb) {
                         struct sk_buff *skb;
-                        skb = netdev_alloc_skb(adapter->netdev, bufsz);
+                        skb = netdev_alloc_skb(adapter->netdev,
+                                               (rx_ring->rx_buf_len +
+                                                NET_IP_ALIGN));
 
                         if (!skb) {
                                 adapter->alloc_rx_buff_failed++;
@@ -608,7 +609,8 @@ static void ixgbe_alloc_rx_buffers(struct ixgbe_adapter *adapter,
                         skb_reserve(skb, NET_IP_ALIGN);
 
                         bi->skb = skb;
-                        bi->dma = pci_map_single(pdev, skb->data, bufsz,
+                        bi->dma = pci_map_single(pdev, skb->data,
+                                                 rx_ring->rx_buf_len,
                                                  PCI_DMA_FROMDEVICE);
                 }
                 /* Refresh the desc even if buffer_addrs didn't change because
@@ -732,6 +734,7 @@ static bool ixgbe_clean_rx_irq(struct ixgbe_q_vector *q_vector,
                         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);
                 }
 
@@ -2815,9 +2818,11 @@ static void ixgbe_clean_rx_ring(struct ixgbe_adapter *adapter,
                 }
                 if (!rx_buffer_info->page)
                         continue;
-                pci_unmap_page(pdev, rx_buffer_info->page_dma, PAGE_SIZE / 2,
-                               PCI_DMA_FROMDEVICE);
-                rx_buffer_info->page_dma = 0;
+                if (rx_buffer_info->page_dma) {
+                        pci_unmap_page(pdev, rx_buffer_info->page_dma,
+                                       PAGE_SIZE / 2, PCI_DMA_FROMDEVICE);
+                        rx_buffer_info->page_dma = 0;
+                }
                 put_page(rx_buffer_info->page);
                 rx_buffer_info->page = NULL;
                 rx_buffer_info->page_offset = 0;