s390/pci: improve state check when processing hotplug events

Processing pci hotplug events can fail when a pci function is in an
unexpected state. This can happen when we already processed the
change associated with the hotplug event (especially when receiving
hotplug events during early boot).
Just ignore the event in this case.
Reviewed-by: NGerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: NSebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/pci/pci_event.c

@@ -76,7 +76,7 @@ static void __zpci_event_availability(struct zpci_ccdf_avail *ccdf)
 
 	switch (ccdf->pec) {
 	case 0x0301: /* Standby -> Configured */
-		if (!zdev || zdev->state == ZPCI_FN_STATE_CONFIGURED)
+		if (!zdev || zdev->state != ZPCI_FN_STATE_STANDBY)
 			break;
 		zdev->state = ZPCI_FN_STATE_CONFIGURED;
 		zdev->fh = ccdf->fh;
@@ -86,7 +86,8 @@ static void __zpci_event_availability(struct zpci_ccdf_avail *ccdf)
 		pci_rescan_bus(zdev->bus);
 		break;
 	case 0x0302: /* Reserved -> Standby */
-		clp_add_pci_device(ccdf->fid, ccdf->fh, 0);
+		if (!zdev)
+			clp_add_pci_device(ccdf->fid, ccdf->fh, 0);
 		break;
 	case 0x0303: /* Deconfiguration requested */
 		if (pdev)