[S390] tape: Fix medium state handling

Currently there are situations, where the tape medium state (loaded, unloaded,
unknown) is not set correctly. The reason is that the medium association
field is used to determine the medium state. This not always leads to
correct results. To fix that we use another field of the medium sense
data instead.
Signed-off-by: Michael Holzheu <holzheu@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

drivers/s390/char/tape_3590.c

@@ -708,16 +708,22 @@ static void tape_3590_med_state_set(struct tape_device *device,
 
 	c_info = &TAPE_3590_CRYPT_INFO(device);
 
-	if (sense->masst == MSENSE_UNASSOCIATED) {
+	DBF_EVENT(6, "medium state: %x:%x\n", sense->macst, sense->masst);
+	switch (sense->macst) {
+	case 0x04:
+	case 0x05:
+	case 0x06:
 		tape_med_state_set(device, MS_UNLOADED);
 		TAPE_3590_CRYPT_INFO(device).medium_status = 0;
 		return;
-	}
-	if (sense->masst != MSENSE_ASSOCIATED_MOUNT) {
-		PRINT_ERR("Unknown medium state: %x\n", sense->masst);
+	case 0x08:
+	case 0x09:
+		tape_med_state_set(device, MS_LOADED);
+		break;
+	default:
+		tape_med_state_set(device, MS_UNKNOWN);
 		return;
 	}
-	tape_med_state_set(device, MS_LOADED);
 	c_info->medium_status |= TAPE390_MEDIUM_LOADED_MASK;
 	if (sense->flags & MSENSE_CRYPT_MASK) {
 		PRINT_INFO("Medium is encrypted (%04x)\n", sense->flags);
@@ -835,15 +841,17 @@ tape_3590_unsolicited_irq(struct tape_device *device, struct irb *irb)
 		/* Probably result of halt ssch */
 		return TAPE_IO_PENDING;
 	else if (irb->scsw.dstat == 0x85)
-		/* Device Ready -> check medium state */
-		tape_3590_schedule_work(device, TO_MSEN);
-	else if (irb->scsw.dstat & DEV_STAT_ATTENTION)
+		/* Device Ready */
+		DBF_EVENT(3, "unsol.irq! tape ready: %08x\n", device->cdev_id);
+	else if (irb->scsw.dstat & DEV_STAT_ATTENTION) {
 		tape_3590_schedule_work(device, TO_READ_ATTMSG);
-	else {
+	} else {
 		DBF_EVENT(3, "unsol.irq! dev end: %08x\n", device->cdev_id);
 		PRINT_WARN("Unsolicited IRQ (Device End) caught.\n");
 		tape_dump_sense(device, NULL, irb);
 	}
+	/* check medium state */
+	tape_3590_schedule_work(device, TO_MSEN);
 	return TAPE_IO_SUCCESS;
 }