net: atlantic: possible fault in transition to hibernation

during hibernation freeze, aq_nic_stop could be invoked
on a stopped device. That may cause panic on access to
not yet allocated vector/ring structures.

Add a check to stop device if it is not yet stopped.

Similiarly after freeze in hibernation thaw, aq_nic_start
could be invoked on a not initialized net device.
Result will be the same.

Add a check to start device if it is initialized.
In our case, this is the same as started.

Fixes: 8aaa112a ("net: atlantic: refactoring pm logic")
Signed-off-by: Pavel Belous <pbelous@marvell.com>
Signed-off-by: Nikita Danilov <ndanilov@marvell.com>
Signed-off-by: Igor Russkikh <irusskikh@marvell.com>
Signed-off-by: Dmitry Bogdanov <dbogdanov@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/aquantia/atlantic/aq_pci_func.c

@@ -359,7 +359,8 @@ static int aq_suspend_common(struct device *dev, bool deep)
 	netif_device_detach(nic->ndev);
 	netif_tx_stop_all_queues(nic->ndev);
 
-	aq_nic_stop(nic);
+	if (netif_running(nic->ndev))
+		aq_nic_stop(nic);
 
 	if (deep) {
 		aq_nic_deinit(nic, !nic->aq_hw->aq_nic_cfg->wol);
@@ -375,7 +376,7 @@ static int atl_resume_common(struct device *dev, bool deep)
 {
 	struct pci_dev *pdev = to_pci_dev(dev);
 	struct aq_nic_s *nic;
-	int ret;
+	int ret = 0;
 
 	nic = pci_get_drvdata(pdev);
 
@@ -390,9 +391,11 @@ static int atl_resume_common(struct device *dev, bool deep)
 			goto err_exit;
 	}
 
-	ret = aq_nic_start(nic);
-	if (ret)
-		goto err_exit;
+	if (netif_running(nic->ndev)) {
+		ret = aq_nic_start(nic);
+		if (ret)
+			goto err_exit;
+	}
 
 	netif_device_attach(nic->ndev);
 	netif_tx_start_all_queues(nic->ndev);