e1000e: Avoid wrong check on TX hang

Based on the original patch submitted my Michael Wang
<wangyun@linux.vnet.ibm.com>.
Descriptors may not be write-back while checking TX hang with flag
FLAG2_DMA_BURST on.
So when we detect hang, we just flush the descriptor and detect
again for once.

-v2 change 1 to true and 0 to false and remove extra ()

CC: Michael Wang <wangyun@linux.vnet.ibm.com>
CC: Flavio Leitner <fbl@redhat.com>
Acked-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

diff --git a/drivers/net/ethernet/intel/e1000e/e1000.h b/drivers/net/ethernet/intel/e1000e/e1000.h
index 9fe18d1d53d8eaf34f4b2825c5a7fd9bc2c14b2b..f478a22ed57768e1f1b88207236a7b673e8b20f7 100644 (file)
--- a/drivers/net/ethernet/intel/e1000e/e1000.h
+++ b/drivers/net/ethernet/intel/e1000e/e1000.h
@@ -309,6 +309,7 @@ struct e1000_adapter {
        u32 txd_cmd;
 
        bool detect_tx_hung;
+       bool tx_hang_recheck;
        u8 tx_timeout_factor;
 
        u32 tx_int_delay;

diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
index c6e976302f97f0f1fe0a5a81e0e435b6a089757c..c12df6972b35e451fb68ce4f5f8aa44ab08eaa1f 100644 (file)
--- a/drivers/net/ethernet/intel/e1000e/netdev.c
+++ b/drivers/net/ethernet/intel/e1000e/netdev.c
@@ -1014,6 +1014,7 @@ static void e1000_print_hw_hang(struct work_struct *work)
        struct e1000_adapter *adapter = container_of(work,
                                                     struct e1000_adapter,
                                                     print_hang_task);
+       struct net_device *netdev = adapter->netdev;
        struct e1000_ring *tx_ring = adapter->tx_ring;
        unsigned int i = tx_ring->next_to_clean;
        unsigned int eop = tx_ring->buffer_info[i].next_to_watch;
@@ -1025,6 +1026,21 @@ static void e1000_print_hw_hang(struct work_struct *work)
        if (test_bit(__E1000_DOWN, &adapter->state))
                return;
 
+       if (!adapter->tx_hang_recheck &&
+           (adapter->flags2 & FLAG2_DMA_BURST)) {
+               /* May be block on write-back, flush and detect again
+                * flush pending descriptor writebacks to memory
+                */
+               ew32(TIDV, adapter->tx_int_delay | E1000_TIDV_FPD);
+               /* execute the writes immediately */
+               e1e_flush();
+               adapter->tx_hang_recheck = true;
+               return;
+       }
+       /* Real hang detected */
+       adapter->tx_hang_recheck = false;
+       netif_stop_queue(netdev);
+
        e1e_rphy(hw, PHY_STATUS, &phy_status);
        e1e_rphy(hw, PHY_1000T_STATUS, &phy_1000t_status);
        e1e_rphy(hw, PHY_EXT_STATUS, &phy_ext_status);
@@ -1145,10 +1161,10 @@ static bool e1000_clean_tx_irq(struct e1000_adapter *adapter)
                if (tx_ring->buffer_info[i].time_stamp &&
                    time_after(jiffies, tx_ring->buffer_info[i].time_stamp
                               + (adapter->tx_timeout_factor * HZ)) &&
-                   !(er32(STATUS) & E1000_STATUS_TXOFF)) {
+                   !(er32(STATUS) & E1000_STATUS_TXOFF))
                        schedule_work(&adapter->print_hang_task);
-                       netif_stop_queue(netdev);
-               }
+               else
+                       adapter->tx_hang_recheck = false;
        }
        adapter->total_tx_bytes += total_tx_bytes;
        adapter->total_tx_packets += total_tx_packets;
@@ -3838,6 +3854,7 @@ static int e1000_open(struct net_device *netdev)
 
        e1000_irq_enable(adapter);
 
+       adapter->tx_hang_recheck = false;
        netif_start_queue(netdev);
 
        adapter->idle_check = true;