igb: fix panic while dumping packets on Tx hang with IOMMU

This patch resolves a "BUG: unable to handle kernel paging request at ..."
oops while dumping packet data. The issue occurs with IOMMU enabled due to
the address provided by phys_to_virt().

This patch avoids phys_to_virt() by making using skb->data and the address
of the pages allocated for Rx.

Signed-off-by: Emil Tantilov <emil.s.tantilov@intel.com>
Tested-by: Jeff Pieper <jeffrey.e.pieper@intel.com>
Signed-off-by: Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@intel.com>

1 files changed, 9 insertions, 10 deletions

diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index b7c2d5050572..48cc4fb1a307 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -462,10 +462,10 @@ static void igb_dump(struct igb_adapter *adapter)
                                 (u64)buffer_info->time_stamp,
                                 buffer_info->skb, next_desc);
 
-                        if (netif_msg_pktdata(adapter) && buffer_info->dma != 0)
+                        if (netif_msg_pktdata(adapter) && buffer_info->skb)
                                 print_hex_dump(KERN_INFO, "",
                                         DUMP_PREFIX_ADDRESS,
-                                        16, 1, phys_to_virt(buffer_info->dma),
+                                        16, 1, buffer_info->skb->data,
                                         buffer_info->length, true);
                 }
         }
@@ -547,18 +547,17 @@ rx_ring_summary:
                                         (u64)buffer_info->dma,
                                         buffer_info->skb, next_desc);
 
-                                if (netif_msg_pktdata(adapter)) {
+                                if (netif_msg_pktdata(adapter) &&
+                                    buffer_info->dma && buffer_info->skb) {
                                         print_hex_dump(KERN_INFO, "",
-                                                DUMP_PREFIX_ADDRESS,
-                                                16, 1,
-                                                phys_to_virt(buffer_info->dma),
-                                                IGB_RX_HDR_LEN, true);
+                                                  DUMP_PREFIX_ADDRESS,
+                                                  16, 1, buffer_info->skb->data,
+                                                  IGB_RX_HDR_LEN, true);
                                         print_hex_dump(KERN_INFO, "",
                                           DUMP_PREFIX_ADDRESS,
                                           16, 1,
-                                          phys_to_virt(
-                                            buffer_info->page_dma +
-                                            buffer_info->page_offset),
+                                          page_address(buffer_info->page) +
+                                                      buffer_info->page_offset,
                                           PAGE_SIZE/2, true);
                                 }
                         }