igb: Do not bring the device up after non-fatal error

Commit 004d250 ("igb: Fix igb_down hung on surprise removal")
changed igb_io_error_detected() to ignore non-fatal pcie errors in order
to avoid hung task that can happen when igb_down() is called multiple
times. This caused an issue when processing transient non-fatal errors.
igb_io_resume(), which is called after igb_io_error_detected(), assumes
that device is brought down by igb_io_error_detected() if the interface
is up. This resulted in panic with stacktrace below.

[ T3256] igb 0000:09:00.0 haeth0: igb: haeth0 NIC Link is Down
[  T292] pcieport 0000:00:1c.5: AER: Uncorrected (Non-Fatal) error received: 0000:09:00.0
[  T292] igb 0000:09:00.0: PCIe Bus Error: severity=Uncorrected (Non-Fatal), type=Transaction Layer, (Requester ID)
[  T292] igb 0000:09:00.0:   device [8086:1537] error status/mask=00004000/00000000
[  T292] igb 0000:09:00.0:    [14] CmpltTO [  200.105524,009][  T292] igb 0000:09:00.0: AER:   TLP Header: 00000000 00000000 00000000 00000000
[  T292] pcieport 0000:00:1c.5: AER: broadcast error_detected message
[  T292] igb 0000:09:00.0: Non-correctable non-fatal error reported.
[  T292] pcieport 0000:00:1c.5: AER: broadcast mmio_enabled message
[  T292] pcieport 0000:00:1c.5: AER: broadcast resume message
[  T292] ------------[ cut here ]------------
[  T292] kernel BUG at net/core/dev.c:6539!
[  T292] invalid opcode: 0000 [#1] PREEMPT SMP
[  T292] RIP: 0010:napi_enable+0x37/0x40
[  T292] Call Trace:
[  T292]  <TASK>
[  T292]  ? die+0x33/0x90
[  T292]  ? do_trap+0xdc/0x110
[  T292]  ? napi_enable+0x37/0x40
[  T292]  ? do_error_trap+0x70/0xb0
[  T292]  ? napi_enable+0x37/0x40
[  T292]  ? napi_enable+0x37/0x40
[  T292]  ? exc_invalid_op+0x4e/0x70
[  T292]  ? napi_enable+0x37/0x40
[  T292]  ? asm_exc_invalid_op+0x16/0x20
[  T292]  ? napi_enable+0x37/0x40
[  T292]  igb_up+0x41/0x150
[  T292]  igb_io_resume+0x25/0x70
[  T292]  report_resume+0x54/0x70
[  T292]  ? report_frozen_detected+0x20/0x20
[  T292]  pci_walk_bus+0x6c/0x90
[  T292]  ? aer_print_port_info+0xa0/0xa0
[  T292]  pcie_do_recovery+0x22f/0x380
[  T292]  aer_process_err_devices+0x110/0x160
[  T292]  aer_isr+0x1c1/0x1e0
[  T292]  ? disable_irq_nosync+0x10/0x10
[  T292]  irq_thread_fn+0x1a/0x60
[  T292]  irq_thread+0xe3/0x1a0
[  T292]  ? irq_set_affinity_notifier+0x120/0x120
[  T292]  ? irq_affinity_notify+0x100/0x100
[  T292]  kthread+0xe2/0x110
[  T292]  ? kthread_complete_and_exit+0x20/0x20
[  T292]  ret_from_fork+0x2d/0x50
[  T292]  ? kthread_complete_and_exit+0x20/0x20
[  T292]  ret_from_fork_asm+0x11/0x20
[  T292]  </TASK>

To fix this issue igb_io_resume() checks if the interface is running and
the device is not down this means igb_io_error_detected() did not bring
the device down and there is no need to bring it up.

Signed-off-by: Mohamed Khalfella <mkhalfella@purestorage.com>
Reviewed-by: Yuanyuan Zhong <yzhong@purestorage.com>
Fixes: 004d250 ("igb: Fix igb_down hung on surprise removal")
Reviewed-by: Simon Horman <horms@kernel.org>
Tested-by: Pucha Himasekhar Reddy <himasekharx.reddy.pucha@intel.com> (A Contingent worker at Intel)
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

Author: Mohamed Khalfella

drivers/net/ethernet/intel/igb/igb_main.c

@@ -9651,6 +9651,10 @@ static void igb_io_resume(struct pci_dev *pdev)
 	struct igb_adapter *adapter = netdev_priv(netdev);
 
 	if (netif_running(netdev)) {
+		if (!test_bit(__IGB_DOWN, &adapter->state)) {
+			dev_dbg(&pdev->dev, "Resuming from non-fatal error, do nothing.\n");
+			return;
+		}
 		if (igb_up(adapter)) {
 			dev_err(&pdev->dev, "igb_up failed after reset\n");
 			return;