4 files changed, 86 insertions, 183 deletions

diff --git a/drivers/s390/block/dasd_alias.c b/drivers/s390/block/dasd_alias.c
index 17ad5749e91d..1e560188dd13 100644
--- a/drivers/s390/block/dasd_alias.c
+++ b/drivers/s390/block/dasd_alias.c
@@ -317,17 +317,17 @@ static int _add_device_to_lcu(struct alias_lcu *lcu,
 	struct alias_pav_group *group;
 	struct dasd_uid uid;
 
+	spin_lock(get_ccwdev_lock(device->cdev));
 	private->uid.type = lcu->uac->unit[private->uid.real_unit_addr].ua_type;
 	private->uid.base_unit_addr =
 		lcu->uac->unit[private->uid.real_unit_addr].base_ua;
 	uid = private->uid;
-
+	spin_unlock(get_ccwdev_lock(device->cdev));
 	/* if we have no PAV anyway, we don't need to bother with PAV groups */
 	if (lcu->pav == NO_PAV) {
 		list_move(&device->alias_list, &lcu->active_devices);
 		return 0;
 	}
-
 	group = _find_group(lcu, &uid);
 	if (!group) {
 		group = kzalloc(sizeof(*group), GFP_ATOMIC);
@@ -397,130 +397,6 @@ suborder_not_supported(struct dasd_ccw_req *cqr)
 	return 0;
 }
 
-/*
- * This function tries to lock all devices on an lcu via trylock
- * return NULL on success otherwise return first failed device
- */
-static struct dasd_device *_trylock_all_devices_on_lcu(struct alias_lcu *lcu,
-						      struct dasd_device *pos)
-
-{
-	struct alias_pav_group *pavgroup;
-	struct dasd_device *device;
-
-	list_for_each_entry(device, &lcu->active_devices, alias_list) {
-		if (device == pos)
-			continue;
-		if (!spin_trylock(get_ccwdev_lock(device->cdev)))
-			return device;
-	}
-	list_for_each_entry(device, &lcu->inactive_devices, alias_list) {
-		if (device == pos)
-			continue;
-		if (!spin_trylock(get_ccwdev_lock(device->cdev)))
-			return device;
-	}
-	list_for_each_entry(pavgroup, &lcu->grouplist, group) {
-		list_for_each_entry(device, &pavgroup->baselist, alias_list) {
-			if (device == pos)
-				continue;
-			if (!spin_trylock(get_ccwdev_lock(device->cdev)))
-				return device;
-		}
-		list_for_each_entry(device, &pavgroup->aliaslist, alias_list) {
-			if (device == pos)
-				continue;
-			if (!spin_trylock(get_ccwdev_lock(device->cdev)))
-				return device;
-		}
-	}
-	return NULL;
-}
-
-/*
- * unlock all devices except the one that is specified as pos
- * stop if enddev is specified and reached
- */
-static void _unlock_all_devices_on_lcu(struct alias_lcu *lcu,
-				       struct dasd_device *pos,
-				       struct dasd_device *enddev)
-
-{
-	struct alias_pav_group *pavgroup;
-	struct dasd_device *device;
-
-	list_for_each_entry(device, &lcu->active_devices, alias_list) {
-		if (device == pos)
-			continue;
-		if (device == enddev)
-			return;
-		spin_unlock(get_ccwdev_lock(device->cdev));
-	}
-	list_for_each_entry(device, &lcu->inactive_devices, alias_list) {
-		if (device == pos)
-			continue;
-		if (device == enddev)
-			return;
-		spin_unlock(get_ccwdev_lock(device->cdev));
-	}
-	list_for_each_entry(pavgroup, &lcu->grouplist, group) {
-		list_for_each_entry(device, &pavgroup->baselist, alias_list) {
-			if (device == pos)
-				continue;
-			if (device == enddev)
-				return;
-			spin_unlock(get_ccwdev_lock(device->cdev));
-		}
-		list_for_each_entry(device, &pavgroup->aliaslist, alias_list) {
-			if (device == pos)
-				continue;
-			if (device == enddev)
-				return;
-			spin_unlock(get_ccwdev_lock(device->cdev));
-		}
-	}
-}
-
-/*
- *  this function is needed because the locking order
- *  device lock -> lcu lock
- *  needs to be assured when iterating over devices in an LCU
- *
- *  if a device is specified in pos then the device lock is already hold
- */
-static void _trylock_and_lock_lcu_irqsave(struct alias_lcu *lcu,
-					  struct dasd_device *pos,
-					  unsigned long *flags)
-{
-	struct dasd_device *failed;
-
-	do {
-		spin_lock_irqsave(&lcu->lock, *flags);
-		failed = _trylock_all_devices_on_lcu(lcu, pos);
-		if (failed) {
-			_unlock_all_devices_on_lcu(lcu, pos, failed);
-			spin_unlock_irqrestore(&lcu->lock, *flags);
-			cpu_relax();
-		}
-	} while (failed);
-}
-
-static void _trylock_and_lock_lcu(struct alias_lcu *lcu,
-				  struct dasd_device *pos)
-{
-	struct dasd_device *failed;
-
-	do {
-		spin_lock(&lcu->lock);
-		failed = _trylock_all_devices_on_lcu(lcu, pos);
-		if (failed) {
-			_unlock_all_devices_on_lcu(lcu, pos, failed);
-			spin_unlock(&lcu->lock);
-			cpu_relax();
-		}
-	} while (failed);
-}
-
 static int read_unit_address_configuration(struct dasd_device *device,
 					   struct alias_lcu *lcu)
 {
@@ -615,7 +491,7 @@ static int _lcu_update(struct dasd_device *refdev, struct alias_lcu *lcu)
 	if (rc)
 		return rc;
 
-	_trylock_and_lock_lcu_irqsave(lcu, NULL, &flags);
+	spin_lock_irqsave(&lcu->lock, flags);
 	lcu->pav = NO_PAV;
 	for (i = 0; i < MAX_DEVICES_PER_LCU; ++i) {
 		switch (lcu->uac->unit[i].ua_type) {
@@ -634,7 +510,6 @@ static int _lcu_update(struct dasd_device *refdev, struct alias_lcu *lcu)
 				 alias_list) {
 		_add_device_to_lcu(lcu, device, refdev);
 	}
-	_unlock_all_devices_on_lcu(lcu, NULL, NULL);
 	spin_unlock_irqrestore(&lcu->lock, flags);
 	return 0;
 }
@@ -722,8 +597,7 @@ int dasd_alias_add_device(struct dasd_device *device)
 
 	lcu = private->lcu;
 	rc = 0;
-	spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
-	spin_lock(&lcu->lock);
+	spin_lock_irqsave(&lcu->lock, flags);
 	if (!(lcu->flags & UPDATE_PENDING)) {
 		rc = _add_device_to_lcu(lcu, device, device);
 		if (rc)
@@ -733,8 +607,7 @@ int dasd_alias_add_device(struct dasd_device *device)
 		list_move(&device->alias_list, &lcu->active_devices);
 		_schedule_lcu_update(lcu, device);
 	}
-	spin_unlock(&lcu->lock);
-	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
+	spin_unlock_irqrestore(&lcu->lock, flags);
 	return rc;
 }
 
@@ -933,15 +806,27 @@ static void _stop_all_devices_on_lcu(struct alias_lcu *lcu)
 	struct alias_pav_group *pavgroup;
 	struct dasd_device *device;
 
-	list_for_each_entry(device, &lcu->active_devices, alias_list)
+	list_for_each_entry(device, &lcu->active_devices, alias_list) {
+		spin_lock(get_ccwdev_lock(device->cdev));
 		dasd_device_set_stop_bits(device, DASD_STOPPED_SU);
-	list_for_each_entry(device, &lcu->inactive_devices, alias_list)
+		spin_unlock(get_ccwdev_lock(device->cdev));
+	}
+	list_for_each_entry(device, &lcu->inactive_devices, alias_list) {
+		spin_lock(get_ccwdev_lock(device->cdev));
 		dasd_device_set_stop_bits(device, DASD_STOPPED_SU);
+		spin_unlock(get_ccwdev_lock(device->cdev));
+	}
 	list_for_each_entry(pavgroup, &lcu->grouplist, group) {
-		list_for_each_entry(device, &pavgroup->baselist, alias_list)
+		list_for_each_entry(device, &pavgroup->baselist, alias_list) {
+			spin_lock(get_ccwdev_lock(device->cdev));
 			dasd_device_set_stop_bits(device, DASD_STOPPED_SU);
-		list_for_each_entry(device, &pavgroup->aliaslist, alias_list)
+			spin_unlock(get_ccwdev_lock(device->cdev));
+		}
+		list_for_each_entry(device, &pavgroup->aliaslist, alias_list) {
+			spin_lock(get_ccwdev_lock(device->cdev));
 			dasd_device_set_stop_bits(device, DASD_STOPPED_SU);
+			spin_unlock(get_ccwdev_lock(device->cdev));
+		}
 	}
 }
 
@@ -950,15 +835,27 @@ static void _unstop_all_devices_on_lcu(struct alias_lcu *lcu)
 	struct alias_pav_group *pavgroup;
 	struct dasd_device *device;
 
-	list_for_each_entry(device, &lcu->active_devices, alias_list)
+	list_for_each_entry(device, &lcu->active_devices, alias_list) {
+		spin_lock(get_ccwdev_lock(device->cdev));
 		dasd_device_remove_stop_bits(device, DASD_STOPPED_SU);
-	list_for_each_entry(device, &lcu->inactive_devices, alias_list)
+		spin_unlock(get_ccwdev_lock(device->cdev));
+	}
+	list_for_each_entry(device, &lcu->inactive_devices, alias_list) {
+		spin_lock(get_ccwdev_lock(device->cdev));
 		dasd_device_remove_stop_bits(device, DASD_STOPPED_SU);
+		spin_unlock(get_ccwdev_lock(device->cdev));
+	}
 	list_for_each_entry(pavgroup, &lcu->grouplist, group) {
-		list_for_each_entry(device, &pavgroup->baselist, alias_list)
+		list_for_each_entry(device, &pavgroup->baselist, alias_list) {
+			spin_lock(get_ccwdev_lock(device->cdev));
 			dasd_device_remove_stop_bits(device, DASD_STOPPED_SU);
-		list_for_each_entry(device, &pavgroup->aliaslist, alias_list)
+			spin_unlock(get_ccwdev_lock(device->cdev));
+		}
+		list_for_each_entry(device, &pavgroup->aliaslist, alias_list) {
+			spin_lock(get_ccwdev_lock(device->cdev));
 			dasd_device_remove_stop_bits(device, DASD_STOPPED_SU);
+			spin_unlock(get_ccwdev_lock(device->cdev));
+		}
 	}
 }
 
@@ -984,48 +881,32 @@ static void summary_unit_check_handling_work(struct work_struct *work)
 	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
 	reset_summary_unit_check(lcu, device, suc_data->reason);
 
-	_trylock_and_lock_lcu_irqsave(lcu, NULL, &flags);
+	spin_lock_irqsave(&lcu->lock, flags);
 	_unstop_all_devices_on_lcu(lcu);
 	_restart_all_base_devices_on_lcu(lcu);
 	/* 3. read new alias configuration */
 	_schedule_lcu_update(lcu, device);
 	lcu->suc_data.device = NULL;
 	dasd_put_device(device);
-	_unlock_all_devices_on_lcu(lcu, NULL, NULL);
 	spin_unlock_irqrestore(&lcu->lock, flags);
 }
 
-/*
- * note: this will be called from int handler context (cdev locked)
- */
-void dasd_alias_handle_summary_unit_check(struct dasd_device *device,
-					  struct irb *irb)
+void dasd_alias_handle_summary_unit_check(struct work_struct *work)
 {
+	struct dasd_device *device = container_of(work, struct dasd_device,
+						  suc_work);
 	struct dasd_eckd_private *private = device->private;
 	struct alias_lcu *lcu;
-	char reason;
-	char *sense;
-
-	sense = dasd_get_sense(irb);
-	if (sense) {
-		reason = sense[8];
-		DBF_DEV_EVENT(DBF_NOTICE, device, "%s %x",
-			    "eckd handle summary unit check: reason", reason);
-	} else {
-		DBF_DEV_EVENT(DBF_WARNING, device, "%s",
-			    "eckd handle summary unit check:"
-			    " no reason code available");
-		return;
-	}
+	unsigned long flags;
 
 	lcu = private->lcu;
 	if (!lcu) {
 		DBF_DEV_EVENT(DBF_WARNING, device, "%s",
 			    "device not ready to handle summary"
 			    " unit check (no lcu structure)");
-		return;
+		goto out;
 	}
-	_trylock_and_lock_lcu(lcu, device);
+	spin_lock_irqsave(&lcu->lock, flags);
 	/* If this device is about to be removed just return and wait for
 	 * the next interrupt on a different device
 	 */
@@ -1033,27 +914,26 @@ void dasd_alias_handle_summary_unit_check(struct dasd_device *device,
 		DBF_DEV_EVENT(DBF_WARNING, device, "%s",
 			    "device is in offline processing,"
 			    " don't do summary unit check handling");
-		_unlock_all_devices_on_lcu(lcu, device, NULL);
-		spin_unlock(&lcu->lock);
-		return;
+		goto out_unlock;
 	}
 	if (lcu->suc_data.device) {
 		/* already scheduled or running */
 		DBF_DEV_EVENT(DBF_WARNING, device, "%s",
 			    "previous instance of summary unit check worker"
 			    " still pending");
-		_unlock_all_devices_on_lcu(lcu, device, NULL);
-		spin_unlock(&lcu->lock);
-		return ;
+		goto out_unlock;
 	}
 	_stop_all_devices_on_lcu(lcu);
 	/* prepare for lcu_update */
-	private->lcu->flags |= NEED_UAC_UPDATE | UPDATE_PENDING;
-	lcu->suc_data.reason = reason;
+	lcu->flags |= NEED_UAC_UPDATE | UPDATE_PENDING;
+	lcu->suc_data.reason = private->suc_reason;
 	lcu->suc_data.device = device;
 	dasd_get_device(device);
-	_unlock_all_devices_on_lcu(lcu, device, NULL);
-	spin_unlock(&lcu->lock);
 	if (!schedule_work(&lcu->suc_data.worker))
 		dasd_put_device(device);
+out_unlock:
+	spin_unlock_irqrestore(&lcu->lock, flags);
+out:
+	clear_bit(DASD_FLAG_SUC, &device->flags);
+	dasd_put_device(device);
 };
diff --git a/drivers/s390/block/dasd_eckd.c b/drivers/s390/block/dasd_eckd.c
index 75c032dcf173..c1b4ae55e129 100644
--- a/drivers/s390/block/dasd_eckd.c
+++ b/drivers/s390/block/dasd_eckd.c
@@ -1682,6 +1682,8 @@ dasd_eckd_check_characteristics(struct dasd_device *device)
 
 	/* setup work queue for validate server*/
 	INIT_WORK(&device->kick_validate, dasd_eckd_do_validate_server);
+	/* setup work queue for summary unit check */
+	INIT_WORK(&device->suc_work, dasd_alias_handle_summary_unit_check);
 
 	if (!ccw_device_is_pathgroup(device->cdev)) {
 		dev_warn(&device->cdev->dev,
@@ -2549,14 +2551,6 @@ static void dasd_eckd_check_for_device_change(struct dasd_device *device,
 		    device->state == DASD_STATE_ONLINE &&
 		    !test_bit(DASD_FLAG_OFFLINE, &device->flags) &&
 		    !test_bit(DASD_FLAG_SUSPENDED, &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);
 		}
@@ -2571,7 +2565,27 @@ static void dasd_eckd_check_for_device_change(struct dasd_device *device,
 	/* summary unit check */
 	if ((sense[27] & DASD_SENSE_BIT_0) && (sense[7] == 0x0D) &&
 	    (scsw_dstat(&irb->scsw) & DEV_STAT_UNIT_CHECK)) {
-		dasd_alias_handle_summary_unit_check(device, irb);
+		if (test_and_set_bit(DASD_FLAG_SUC, &device->flags)) {
+			DBF_DEV_EVENT(DBF_WARNING, device, "%s",
+				      "eckd suc: device already notified");
+			return;
+		}
+		sense = dasd_get_sense(irb);
+		if (!sense) {
+			DBF_DEV_EVENT(DBF_WARNING, device, "%s",
+				      "eckd suc: no reason code available");
+			clear_bit(DASD_FLAG_SUC, &device->flags);
+			return;
+
+		}
+		private->suc_reason = sense[8];
+		DBF_DEV_EVENT(DBF_NOTICE, device, "%s %x",
+			      "eckd handle summary unit check: reason",
+			      private->suc_reason);
+		dasd_get_device(device);
+		if (!schedule_work(&device->suc_work))
+			dasd_put_device(device);
+
 		return;
 	}
 
@@ -4495,6 +4509,12 @@ static int dasd_eckd_reload_device(struct dasd_device *device)
 	struct dasd_uid uid;
 	unsigned long flags;
 
+	/*
+	 * remove device from alias handling to prevent new requests
+	 * from being scheduled on the wrong alias device
+	 */
+	dasd_alias_remove_device(device);
+
 	spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
 	old_base = private->uid.base_unit_addr;
 	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
diff --git a/drivers/s390/block/dasd_eckd.h b/drivers/s390/block/dasd_eckd.h
index f8f91ee652d3..6d9a6d3517cd 100644
--- a/drivers/s390/block/dasd_eckd.h
+++ b/drivers/s390/block/dasd_eckd.h
@@ -525,6 +525,7 @@ struct dasd_eckd_private {
 	int count;
 
 	u32 fcx_max_data;
+	char suc_reason;
 };
 
 
@@ -534,7 +535,7 @@ void dasd_alias_disconnect_device_from_lcu(struct dasd_device *);
 int dasd_alias_add_device(struct dasd_device *);
 int dasd_alias_remove_device(struct dasd_device *);
 struct dasd_device *dasd_alias_get_start_dev(struct dasd_device *);
-void dasd_alias_handle_summary_unit_check(struct dasd_device *, struct irb *);
+void dasd_alias_handle_summary_unit_check(struct work_struct *);
 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 *);
diff --git a/drivers/s390/block/dasd_int.h b/drivers/s390/block/dasd_int.h
index 8de29be32a56..0f0add932e7a 100644
--- a/drivers/s390/block/dasd_int.h
+++ b/drivers/s390/block/dasd_int.h
@@ -470,6 +470,7 @@ struct dasd_device {
 	struct work_struct restore_device;
 	struct work_struct reload_device;
 	struct work_struct kick_validate;
+	struct work_struct suc_work;
 	struct timer_list timer;
 
 	debug_info_t *debug_area;
@@ -542,6 +543,7 @@ struct dasd_attention_data {
 #define DASD_FLAG_SAFE_OFFLINE_RUNNING	11	/* safe offline running */
 #define DASD_FLAG_ABORTALL	12	/* Abort all noretry requests */
 #define DASD_FLAG_PATH_VERIFY	13	/* Path verification worker running */
+#define DASD_FLAG_SUC		14	/* unhandled summary unit check */
 
 #define DASD_SLEEPON_START_TAG	((void *) 1)
 #define DASD_SLEEPON_END_TAG	((void *) 2)