3 files changed, 89 insertions, 14 deletions

diff --git a/drivers/s390/block/dasd_alias.c b/drivers/s390/block/dasd_alias.c
index cdc6c049c353..fd1231738ef4 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.
diff --git a/drivers/s390/block/dasd_eckd.c b/drivers/s390/block/dasd_eckd.c
index e38a09b5feae..5819dc02a143 100644
--- a/drivers/s390/block/dasd_eckd.c
+++ b/drivers/s390/block/dasd_eckd.c
@@ -1059,7 +1059,7 @@ dasd_eckd_psf_ssc(struct dasd_device *device, int enable_pav)
 /*
  * Valide storage server of current device.
  */
-static int dasd_eckd_validate_server(struct dasd_device *device)
+static void dasd_eckd_validate_server(struct dasd_device *device)
 {
         int rc;
         struct dasd_eckd_private *private;
@@ -1076,8 +1076,6 @@ static int dasd_eckd_validate_server(struct dasd_device *device)
         private = (struct dasd_eckd_private *) device->private;
         DBF_EVENT_DEVID(DBF_WARNING, device->cdev, "PSF-SSC for SSID %04x "
                         "returned rc=%d", private->uid.ssid, rc);
-        /* RE-Read Configuration Data */
-        return dasd_eckd_read_conf(device);
 }
 
 /*
@@ -1149,12 +1147,21 @@ dasd_eckd_check_characteristics(struct dasd_device *device)
                 rc = is_known;
                 goto out_err2;
         }
+        /*
+         * dasd_eckd_vaildate_server is done on the first device that
+         * is found for an LCU. All later other devices have to wait
+         * for it, so they will read the correct feature codes.
+         */
         if (!is_known) {
-                /* new lcu found */
-                rc = dasd_eckd_validate_server(device); /* will switch pav on */
-                if (rc)
-                        goto out_err3;
-        }
+                dasd_eckd_validate_server(device);
+                dasd_alias_lcu_setup_complete(device);
+        } else
+                dasd_alias_wait_for_lcu_setup(device);
+
+        /* device may report different configuration data after LCU setup */
+        rc = dasd_eckd_read_conf(device);
+        if (rc)
+                goto out_err3;
 
         /* Read Feature Codes */
         dasd_eckd_read_features(device);
@@ -3282,11 +3289,15 @@ int dasd_eckd_restore_device(struct dasd_device *device)
         if (is_known < 0)
                 return is_known;
         if (!is_known) {
-                /* new lcu found */
-                rc = dasd_eckd_validate_server(device); /* will switch pav on */
-                if (rc)
-                        goto out_err;
-        }
+                dasd_eckd_validate_server(device);
+                dasd_alias_lcu_setup_complete(device);
+        } else
+                dasd_alias_wait_for_lcu_setup(device);
+
+        /* RE-Read Configuration Data */
+        rc = dasd_eckd_read_conf(device);
+        if (rc)
+                goto out_err;
 
         /* Read Feature Codes */
         dasd_eckd_read_features(device);
diff --git a/drivers/s390/block/dasd_eckd.h b/drivers/s390/block/dasd_eckd.h
index ad45bcac3ce4..864d53c04201 100644
--- a/drivers/s390/block/dasd_eckd.h
+++ b/drivers/s390/block/dasd_eckd.h
@@ -414,6 +414,7 @@ struct alias_lcu {
         struct summary_unit_check_work_data suc_data;
         struct read_uac_work_data ruac_data;
         struct dasd_ccw_req *rsu_cqr;
+        struct completion lcu_setup;
 };
 
 struct alias_pav_group {
@@ -460,5 +461,6 @@ 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_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 *);
 #endif                          /* DASD_ECKD_H */