i40evf: Don't schedule reset_task when device is being removed

When a host disables and enables a PF device, all the associated
VFs are removed and added back in. It also generates a PFR which in turn
resets all the connected VFs. This behaviour is different from that of
Linux guest on Linux host. Hence we end up in a situation where there's
a PFR and device removal at the same time. And watchdog doesn't have a
clue about this and schedules a reset_task. This patch adds code to send
signal to reset_task that the device is currently being removed.
Signed-off-by: Avinash Dayanand <avinash.dayanand@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/i40evf/i40evf.h

@@ -187,6 +187,7 @@ enum i40evf_state_t {
 enum i40evf_critical_section_t {
 	__I40EVF_IN_CRITICAL_TASK,	/* cannot be interrupted */
 	__I40EVF_IN_CLIENT_TASK,
+	__I40EVF_IN_REMOVE_TASK,	/* device being removed */
 };
 
 /* board specific private data structure */

drivers/net/ethernet/intel/i40evf/i40evf_main.c

@@ -1803,6 +1803,12 @@ static void i40evf_reset_task(struct work_struct *work)
 	int i = 0, err;
 	bool running;
 
+	/* When device is being removed it doesn't make sense to run the reset
+	 * task, just return in such a case.
+	 */
+	if (test_bit(__I40EVF_IN_REMOVE_TASK, &adapter->crit_section))
+		return;
+
 	while (test_and_set_bit(__I40EVF_IN_CLIENT_TASK,
 				&adapter->crit_section))
 		usleep_range(500, 1000);
@@ -3053,7 +3059,8 @@ static void i40evf_remove(struct pci_dev *pdev)
 	struct i40evf_mac_filter *f, *ftmp;
 	struct i40e_hw *hw = &adapter->hw;
 	int err;
-
+	/* Indicate we are in remove and not to run reset_task */
+	set_bit(__I40EVF_IN_REMOVE_TASK, &adapter->crit_section);
 	cancel_delayed_work_sync(&adapter->init_task);
 	cancel_work_sync(&adapter->reset_task);
 	cancel_delayed_work_sync(&adapter->client_task);