e1000e: 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 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, 26 insertions, 10 deletions

diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
index 95b245310f17..46c3b1f9ff89 100644
--- a/drivers/net/ethernet/intel/e1000e/netdev.c
+++ b/drivers/net/ethernet/intel/e1000e/netdev.c
@@ -178,6 +178,24 @@ static void e1000_regdump(struct e1000_hw *hw, struct e1000_reg_info *reginfo)
         pr_info("%-15s %08x %08x\n", rname, regs[0], regs[1]);
 }
 
+static void e1000e_dump_ps_pages(struct e1000_adapter *adapter,
+                                 struct e1000_buffer *bi)
+{
+        int i;
+        struct e1000_ps_page *ps_page;
+
+        for (i = 0; i < adapter->rx_ps_pages; i++) {
+                ps_page = &bi->ps_pages[i];
+
+                if (ps_page->page) {
+                        pr_info("packet dump for ps_page %d:\n", i);
+                        print_hex_dump(KERN_INFO, "", DUMP_PREFIX_ADDRESS,
+                                       16, 1, page_address(ps_page->page),
+                                       PAGE_SIZE, true);
+                }
+        }
+}
+
 /*
  * e1000e_dump - Print registers, Tx-ring and Rx-ring
  */
@@ -299,10 +317,10 @@ static void e1000e_dump(struct e1000_adapter *adapter)
                         (unsigned long long)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),
-                                       buffer_info->length, true);
+                                       16, 1, buffer_info->skb->data,
+                                       buffer_info->skb->len, true);
         }
 
         /* Print Rx Ring Summary */
@@ -381,10 +399,8 @@ rx_ring_summary:
                                         buffer_info->skb, next_desc);
 
                                 if (netif_msg_pktdata(adapter))
-                                        print_hex_dump(KERN_INFO, "",
-                                                DUMP_PREFIX_ADDRESS, 16, 1,
-                                                phys_to_virt(buffer_info->dma),
-                                                adapter->rx_ps_bsize0, true);
+                                        e1000e_dump_ps_pages(adapter,
+                                                             buffer_info);
                         }
                 }
                 break;
@@ -444,12 +460,12 @@ rx_ring_summary:
                                         (unsigned long long)buffer_info->dma,
                                         buffer_info->skb, next_desc);
 
-                                if (netif_msg_pktdata(adapter))
+                                if (netif_msg_pktdata(adapter) &&
+                                    buffer_info->skb)
                                         print_hex_dump(KERN_INFO, "",
                                                        DUMP_PREFIX_ADDRESS, 16,
                                                        1,
-                                                       phys_to_virt
-                                                       (buffer_info->dma),
+                                                       buffer_info->skb->data,
                                                        adapter->rx_buffer_len,
                                                        true);
                         }