net: hibmcge: fix the inappropriate netif_device_detach()

current, driver will call netif_device_detach() in
pci_error_handlers.error_detected() and do reset in
pci_error_handlers.slot_reset().
However, if pci_error_handlers.slot_reset() is not called
after pci_error_handlers.error_detected(),
driver will be detached and unable to recover.

drivers/pci/pcie/err.c/report_error_detected() says:
  If any device in the subtree does not have an error_detected
  callback, PCI_ERS_RESULT_NO_AER_DRIVER prevents subsequent
  error callbacks of any device in the subtree, and will
  exit in the disconnected error state.

Therefore, when the hibmcge device and other devices that do not
support the error_detected callback are under the same subtree,
hibmcge will be unable to do slot_reset even for non-fatal errors.

This path move netif_device_detach() from error_detected() to slot_reset(),
ensuring that detach and reset are always executed together.

Fixes: fd394a3 ("net: hibmcge: Add support for abnormal irq handling feature")
Signed-off-by: Jijie Shao <shaojijie@huawei.com>
Signed-off-by: NipaLocal <nipa@local>

Author: Jijie Shao

drivers/net/ethernet/hisilicon/hibmcge/hbg_err.c

@@ -136,12 +136,11 @@ static pci_ers_result_t hbg_pci_err_detected(struct pci_dev *pdev,
 {
 	struct net_device *netdev = pci_get_drvdata(pdev);
 
-	netif_device_detach(netdev);
-
-	if (state == pci_channel_io_perm_failure)
+	if (state == pci_channel_io_perm_failure) {
+		netif_device_detach(netdev);
 		return PCI_ERS_RESULT_DISCONNECT;
+	}
 
-	pci_disable_device(pdev);
 	return PCI_ERS_RESULT_NEED_RESET;
 }
 
@@ -150,6 +149,9 @@ static pci_ers_result_t hbg_pci_err_slot_reset(struct pci_dev *pdev)
 	struct net_device *netdev = pci_get_drvdata(pdev);
 	struct hbg_priv *priv = netdev_priv(netdev);
 
+	netif_device_detach(netdev);
+	pci_disable_device(pdev);
+
 	if (pci_enable_device(pdev)) {
 		dev_err(&pdev->dev,
 			"failed to re-enable PCI device after reset\n");