[PATCH net 2/3] ionic: detach the netdev in the PCI reset handler

ionic_reset_prepare() tears down the queues, unmaps the BARs and calls
ionic_dev_teardown(), but leaves the netdev attached and registered for
the whole reset window. The ethtool core only refuses to call into a
driver when netif_device_present() is false, so ethtool ops keep running
against a device that is being dismantled underneath them, and
ionic_reset_done() can free idev->port_info out from under one of them
via ionic_setup_one() -> ionic_port_init().

The firmware recovery path already handles this properly:
ionic_lif_handle_fw_down() detaches before tearing anything down; so do
the same here.

No matching netif_device_attach() is needed on the way back up, since
ionic_reset_done() completes through ionic_restart_lif(), which already
re-attaches once the queues are alive again.

Fixes: a79b559e99be ("ionic: add FLR recovery support")
Assisted-by: Claude:claude-opus-5
Signed-off-by: Eric Joyner <redacted>
---
 drivers/net/ethernet/pensando/ionic/ionic_bus_pci.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/ethernet/pensando/ionic/ionic_bus_pci.c b/drivers/net/ethernet/pensando/ionic/ionic_bus_pci.c
index 05f19489ec5c..c15c4c705155 100644
--- a/drivers/net/ethernet/pensando/ionic/ionic_bus_pci.c
+++ b/drivers/net/ethernet/pensando/ionic/ionic_bus_pci.c

@@ -447,6 +447,7 @@ static void ionic_reset_prepare(struct pci_dev *pdev)
 	dev_dbg(ionic->dev, "%s: device stopping\n", __func__);
 
 	set_bit(IONIC_LIF_F_FW_RESET, lif->state);
+	netif_device_detach(lif->netdev);
 
 	timer_delete_sync(&ionic->watchdog_timer);
 	cancel_work_sync(&lif->deferred.work);

-- 
2.43.0