[S390] dasd: add dynamic pav toleration

For base Parallel Access Volume (PAV) there is a fixed mapping of
base and alias devices. With dynamic PAV this mapping can be changed
so that an alias device is used with another base device.
This patch enables the DASD device driver to tolerate dynamic PAV
changes.

Signed-off-by: Stefan Haberland <[e-mail]>
Signed-off-by: Heiko Carstens <[e-mail]>
Signed-off-by: Martin Schwidefsky <[e-mail]>

drivers/s390/block/dasd.c

···
 static void dasd_block_tasklet(struct dasd_block *);
 static void do_kick_device(struct work_struct *);
 static void do_restore_device(struct work_struct *);
+static void do_reload_device(struct work_struct *);
 static void dasd_return_cqr_cb(struct dasd_ccw_req *, void *);
 static void dasd_device_timeout(unsigned long);
 static void dasd_block_timeout(unsigned long);
···
 	device->timer.data = (unsigned long) device;
 	INIT_WORK(&device->kick_work, do_kick_device);
 	INIT_WORK(&device->restore_device, do_restore_device);
+	INIT_WORK(&device->reload_device, do_reload_device);
 	device->state = DASD_STATE_NEW;
 	device->target = DASD_STATE_NEW;
 	mutex_init(&device->state_mutex);
···
 	/* queue call to dasd_kick_device to the kernel event daemon. */
 	schedule_work(&device->kick_work);
 }
+
+/*
+ * dasd_reload_device will schedule a call do do_reload_device to the kernel
+ * event daemon.
+ */
+static void do_reload_device(struct work_struct *work)
+{
+	struct dasd_device *device = container_of(work, struct dasd_device,
+						  reload_device);
+	device->discipline->reload(device);
+	dasd_put_device(device);
+}
+
+void dasd_reload_device(struct dasd_device *device)
+{
+	dasd_get_device(device);
+	/* queue call to dasd_reload_device to the kernel event daemon. */
+	schedule_work(&device->reload_device);
+}
+EXPORT_SYMBOL(dasd_reload_device);
 
 /*
  * dasd_restore_device will schedule a call do do_restore_device to the kernel

drivers/s390/block/dasd_3990_erp.c

···
 						struct dasd_ccw_req *erp)
 {
 	struct dasd_ccw_req *cqr = erp->refers;
+	char *sense;
 
 	if (cqr->block &&
 	    (cqr->block->base != cqr->startdev)) {
+
+		sense = dasd_get_sense(&erp->refers->irb);
+		/*
+		 * dynamic pav may have changed base alias mapping
+		 */
+		if (!test_bit(DASD_FLAG_OFFLINE, &cqr->startdev->flags) && sense
+		    && (sense[0] == 0x10) && (sense[7] == 0x0F)
+		    && (sense[8] == 0x67)) {
+			/*
+			 * remove device from alias handling to prevent new
+			 * requests from being scheduled on the
+			 * wrong alias device
+			 */
+			dasd_alias_remove_device(cqr->startdev);
+
+			/* schedule worker to reload device */
+			dasd_reload_device(cqr->startdev);
+		}
+
 		if (cqr->startdev->features & DASD_FEATURE_ERPLOG) {
 			DBF_DEV_EVENT(DBF_ERR, cqr->startdev,
 				    "ERP on alias device for request %p,"

drivers/s390/block/dasd_alias.c

···
 	return rc;
 }
 
+int dasd_alias_update_add_device(struct dasd_device *device)
+{
+	struct dasd_eckd_private *private;
+	private = (struct dasd_eckd_private *) device->private;
+	private->lcu->flags |= UPDATE_PENDING;
+	return dasd_alias_add_device(device);
+}
+
 int dasd_alias_remove_device(struct dasd_device *device)
 {
 	struct dasd_eckd_private *private;

drivers/s390/block/dasd_eckd.c

···
 
 static int dasd_eckd_online_to_ready(struct dasd_device *device)
 {
+	cancel_work_sync(&device->reload_device);
 	return dasd_alias_remove_device(device);
 };
 
···
 {
 	char mask;
 	char *sense = NULL;
+	struct dasd_eckd_private *private;
 
+	private = (struct dasd_eckd_private *) device->private;
 	/* first of all check for state change pending interrupt */
 	mask = DEV_STAT_ATTENTION | DEV_STAT_DEV_END | DEV_STAT_UNIT_EXCEP;
 	if ((scsw_dstat(&irb->scsw) & mask) == mask) {
+		/* for alias only and not in offline processing*/
+		if (!device->block && private->lcu &&
+		    !test_bit(DASD_FLAG_OFFLINE, &device->flags)) {
+			/*
+			 * the state change could be caused by an alias
+			 * reassignment remove device from alias handling
+			 * to prevent new requests from being scheduled on
+			 * the wrong alias device
+			 */
+			dasd_alias_remove_device(device);
+
+			/* schedule worker to reload device */
+			dasd_reload_device(device);
+		}
+
 		dasd_generic_handle_state_change(device);
 		return;
 	}
···
 		dasd_eckd_dump_sense_ccw(device, req, irb);
 }
 
-int dasd_eckd_pm_freeze(struct dasd_device *device)
+static int dasd_eckd_pm_freeze(struct dasd_device *device)
 {
 	/*
 	 * the device should be disconnected from our LCU structure
···
 	return 0;
 }
 
-int dasd_eckd_restore_device(struct dasd_device *device)
+static int dasd_eckd_restore_device(struct dasd_device *device)
 {
 	struct dasd_eckd_private *private;
 	struct dasd_eckd_characteristics temp_rdc_data;
···
 	return -1;
 }
 
+static int dasd_eckd_reload_device(struct dasd_device *device)
+{
+	struct dasd_eckd_private *private;
+	int rc, old_base;
+	char uid[60];
+
+	private = (struct dasd_eckd_private *) device->private;
+	old_base = private->uid.base_unit_addr;
+	/* Read Configuration Data */
+	rc = dasd_eckd_read_conf(device);
+	if (rc)
+		goto out_err;
+
+	rc = dasd_eckd_generate_uid(device, &private->uid);
+	if (rc)
+		goto out_err;
+
+	dasd_set_uid(device->cdev, &private->uid);
+
+	/*
+	 * update unit address configuration and
+	 * add device to alias management
+	 */
+	dasd_alias_update_add_device(device);
+
+	if (old_base != private->uid.base_unit_addr) {
+		if (strlen(private->uid.vduit) > 0)
+			snprintf(uid, 60, "%s.%s.%04x.%02x.%s",
+				 private->uid.vendor, private->uid.serial,
+				 private->uid.ssid, private->uid.base_unit_addr,
+				 private->uid.vduit);
+		else
+			snprintf(uid, 60, "%s.%s.%04x.%02x",
+				 private->uid.vendor, private->uid.serial,
+				 private->uid.ssid,
+				 private->uid.base_unit_addr);
+
+		dev_info(&device->cdev->dev,
+			 "An Alias device was reassigned to a new base device "
+			 "with UID: %s\n", uid);
+	}
+	return 0;
+
+out_err:
+	return -1;
+}
+
 static struct ccw_driver dasd_eckd_driver = {
 	.name	     = "dasd-eckd",
 	.owner	     = THIS_MODULE,
···
 	.ioctl = dasd_eckd_ioctl,
 	.freeze = dasd_eckd_pm_freeze,
 	.restore = dasd_eckd_restore_device,
+	.reload = dasd_eckd_reload_device,
 };
 
 static int __init

drivers/s390/block/dasd_eckd.h

···
 	struct dasd_device *next;
 };
 
-
 struct dasd_eckd_private {
 	struct dasd_eckd_characteristics rdc_data;
 	u8 *conf_data;
···
 void dasd_eckd_reset_ccw_to_base_io(struct dasd_ccw_req *);
 void dasd_alias_lcu_setup_complete(struct dasd_device *);
 void dasd_alias_wait_for_lcu_setup(struct dasd_device *);
+int dasd_alias_update_add_device(struct dasd_device *);
 #endif				/* DASD_ECKD_H */

drivers/s390/block/dasd_int.h

···
 	/* suspend/resume functions */
 	int (*freeze) (struct dasd_device *);
 	int (*restore) (struct dasd_device *);
+
+	/* reload device after state change */
+	int (*reload) (struct dasd_device *);
 };
 
 extern struct dasd_discipline *dasd_diag_discipline_pointer;
···
         struct tasklet_struct tasklet;
 	struct work_struct kick_work;
 	struct work_struct restore_device;
+	struct work_struct reload_device;
 	struct timer_list timer;
 
 	debug_info_t *debug_area;
···
 void dasd_set_target_state(struct dasd_device *, int);
 void dasd_kick_device(struct dasd_device *);
 void dasd_restore_device(struct dasd_device *);
+void dasd_reload_device(struct dasd_device *);
 
 void dasd_add_request_head(struct dasd_ccw_req *);
 void dasd_add_request_tail(struct dasd_ccw_req *);