e1000e: prevent oops when adapter is being closed and reset simultaneously

When the adapter is closed while it is simultaneously going through a
reset, it can cause a null-pointer dereference when the two different code
paths simultaneously cleanup up the Tx/Rx resources.

Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

2 files changed, 15 insertions, 0 deletions

diff --git a/drivers/net/ethernet/intel/e1000e/e1000.h b/drivers/net/ethernet/intel/e1000e/e1000.h
index 86cdd4793992..b83897f76ee3 100644
--- a/drivers/net/ethernet/intel/e1000e/e1000.h
+++ b/drivers/net/ethernet/intel/e1000e/e1000.h
@@ -161,6 +161,12 @@ struct e1000_info;
 /* Time to wait before putting the device into D3 if there's no link (in ms). */
 #define LINK_TIMEOUT            100
 
+/*
+ * Count for polling __E1000_RESET condition every 10-20msec.
+ * Experimentation has shown the reset can take approximately 210msec.
+ */
+#define E1000_CHECK_RESET_COUNT         25
+
 #define DEFAULT_RDTR                    0
 #define DEFAULT_RADV                    8
 #define BURST_RDTR                      0x20
diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
index 2c38a65ade87..6878601f20c5 100644
--- a/drivers/net/ethernet/intel/e1000e/netdev.c
+++ b/drivers/net/ethernet/intel/e1000e/netdev.c
@@ -3968,6 +3968,10 @@ static int e1000_close(struct net_device *netdev)
 {
         struct e1000_adapter *adapter = netdev_priv(netdev);
         struct pci_dev *pdev = adapter->pdev;
+        int count = E1000_CHECK_RESET_COUNT;
+
+        while (test_bit(__E1000_RESETTING, &adapter->state) && count--)
+                usleep_range(10000, 20000);
 
         WARN_ON(test_bit(__E1000_RESETTING, &adapter->state));
 
@@ -5472,6 +5476,11 @@ static int __e1000_shutdown(struct pci_dev *pdev, bool *enable_wake,
         netif_device_detach(netdev);
 
         if (netif_running(netdev)) {
+                int count = E1000_CHECK_RESET_COUNT;
+
+                while (test_bit(__E1000_RESETTING, &adapter->state) && count--)
+                        usleep_range(10000, 20000);
+
                 WARN_ON(test_bit(__E1000_RESETTING, &adapter->state));
                 e1000e_down(adapter);
                 e1000_free_irq(adapter);