[S390] dasd: let device initialization wait for LCU setup

The first DASD that is set online for a specific logical control unit
has to do certain setup steps on the storage server to make full use
of it, for example it will enable PAV.
The features and characteristics reported by the storage server will
depend on this setup, so all other devices on the same LCU will need
to wait for the setup to be finished.

Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 62 insertions, 0 deletions

diff --git a/drivers/s390/block/dasd_alias.c b/drivers/s390/block/dasd_alias.c
index cdc6c04..fd12317 100644
--- a/drivers/s390/block/dasd_alias.c
+++ b/drivers/s390/block/dasd_alias.c
@@ -152,6 +152,7 @@ static struct alias_lcu *_allocate_lcu(struct dasd_uid *uid)
 	INIT_WORK(&lcu->suc_data.worker, summary_unit_check_handling_work);
 	INIT_DELAYED_WORK(&lcu->ruac_data.dwork, lcu_update_work);
 	spin_lock_init(&lcu->lock);
+	init_completion(&lcu->lcu_setup);
 	return lcu;
 
 out_err4:
@@ -240,6 +241,67 @@ int dasd_alias_make_device_known_to_lcu(struct dasd_device *device)
 }
 
 /*
+ * The first device to be registered on an LCU will have to do
+ * some additional setup steps to configure that LCU on the
+ * storage server. All further devices should wait with their
+ * initialization until the first device is done.
+ * To synchronize this work, the first device will call
+ * dasd_alias_lcu_setup_complete when it is done, and all
+ * other devices will wait for it with dasd_alias_wait_for_lcu_setup.
+ */
+void dasd_alias_lcu_setup_complete(struct dasd_device *device)
+{
+	struct dasd_eckd_private *private;
+	unsigned long flags;
+	struct alias_server *server;
+	struct alias_lcu *lcu;
+	struct dasd_uid *uid;
+
+	private = (struct dasd_eckd_private *) device->private;
+	uid = &private->uid;
+	lcu = NULL;
+	spin_lock_irqsave(&aliastree.lock, flags);
+	server = _find_server(uid);
+	if (server)
+		lcu = _find_lcu(server, uid);
+	spin_unlock_irqrestore(&aliastree.lock, flags);
+	if (!lcu) {
+		DBF_EVENT_DEVID(DBF_ERR, device->cdev,
+				"could not find lcu for %04x %02x",
+				uid->ssid, uid->real_unit_addr);
+		WARN_ON(1);
+		return;
+	}
+	complete_all(&lcu->lcu_setup);
+}
+
+void dasd_alias_wait_for_lcu_setup(struct dasd_device *device)
+{
+	struct dasd_eckd_private *private;
+	unsigned long flags;
+	struct alias_server *server;
+	struct alias_lcu *lcu;
+	struct dasd_uid *uid;
+
+	private = (struct dasd_eckd_private *) device->private;
+	uid = &private->uid;
+	lcu = NULL;
+	spin_lock_irqsave(&aliastree.lock, flags);
+	server = _find_server(uid);
+	if (server)
+		lcu = _find_lcu(server, uid);
+	spin_unlock_irqrestore(&aliastree.lock, flags);
+	if (!lcu) {
+		DBF_EVENT_DEVID(DBF_ERR, device->cdev,
+				"could not find lcu for %04x %02x",
+				uid->ssid, uid->real_unit_addr);
+		WARN_ON(1);
+		return;
+	}
+	wait_for_completion(&lcu->lcu_setup);
+}
+
+/*
  * This function removes a device from the scope of alias management.
  * The complicated part is to make sure that it is not in use by
  * any of the workers. If necessary cancel the work.