[S390] dasd: remove uid from devmap

Remove the duplicate of the DASD uid from the devmap structure.
Use the uid from the device private structure instead.
This also removes a lockdep warning complaining about a possible
SOFTIRQ-safe -> SOFTIRQ-unsafe lock order.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

4 files changed, 218 insertions, 195 deletions

diff --git a/drivers/s390/block/dasd_alias.c b/drivers/s390/block/dasd_alias.c
index a564b9941114..4155805dcdff 100644
--- a/drivers/s390/block/dasd_alias.c
+++ b/drivers/s390/block/dasd_alias.c
@@ -190,20 +190,21 @@ int dasd_alias_make_device_known_to_lcu(struct dasd_device *device)
         struct alias_server *server, *newserver;
         struct alias_lcu *lcu, *newlcu;
         int is_lcu_known;
-        struct dasd_uid *uid;
+        struct dasd_uid uid;
 
         private = (struct dasd_eckd_private *) device->private;
-        uid = &private->uid;
+
+        device->discipline->get_uid(device, &uid);
         spin_lock_irqsave(&aliastree.lock, flags);
         is_lcu_known = 1;
-        server = _find_server(uid);
+        server = _find_server(&uid);
         if (!server) {
                 spin_unlock_irqrestore(&aliastree.lock, flags);
-                newserver = _allocate_server(uid);
+                newserver = _allocate_server(&uid);
                 if (IS_ERR(newserver))
                         return PTR_ERR(newserver);
                 spin_lock_irqsave(&aliastree.lock, flags);
-                server = _find_server(uid);
+                server = _find_server(&uid);
                 if (!server) {
                         list_add(&newserver->server, &aliastree.serverlist);
                         server = newserver;
@@ -214,14 +215,14 @@ int dasd_alias_make_device_known_to_lcu(struct dasd_device *device)
                 }
         }
 
-        lcu = _find_lcu(server, uid);
+        lcu = _find_lcu(server, &uid);
         if (!lcu) {
                 spin_unlock_irqrestore(&aliastree.lock, flags);
-                newlcu = _allocate_lcu(uid);
+                newlcu = _allocate_lcu(&uid);
                 if (IS_ERR(newlcu))
                         return PTR_ERR(newlcu);
                 spin_lock_irqsave(&aliastree.lock, flags);
-                lcu = _find_lcu(server, uid);
+                lcu = _find_lcu(server, &uid);
                 if (!lcu) {
                         list_add(&newlcu->lcu, &server->lculist);
                         lcu = newlcu;
@@ -256,20 +257,20 @@ void dasd_alias_lcu_setup_complete(struct dasd_device *device)
         unsigned long flags;
         struct alias_server *server;
         struct alias_lcu *lcu;
-        struct dasd_uid *uid;
+        struct dasd_uid uid;
 
         private = (struct dasd_eckd_private *) device->private;
-        uid = &private->uid;
+        device->discipline->get_uid(device, &uid);
         lcu = NULL;
         spin_lock_irqsave(&aliastree.lock, flags);
-        server = _find_server(uid);
+        server = _find_server(&uid);
         if (server)
-                lcu = _find_lcu(server, uid);
+                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);
+                                uid.ssid, uid.real_unit_addr);
                 WARN_ON(1);
                 return;
         }
@@ -282,20 +283,20 @@ void dasd_alias_wait_for_lcu_setup(struct dasd_device *device)
         unsigned long flags;
         struct alias_server *server;
         struct alias_lcu *lcu;
-        struct dasd_uid *uid;
+        struct dasd_uid uid;
 
         private = (struct dasd_eckd_private *) device->private;
-        uid = &private->uid;
+        device->discipline->get_uid(device, &uid);
         lcu = NULL;
         spin_lock_irqsave(&aliastree.lock, flags);
-        server = _find_server(uid);
+        server = _find_server(&uid);
         if (server)
-                lcu = _find_lcu(server, uid);
+                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);
+                                uid.ssid, uid.real_unit_addr);
                 WARN_ON(1);
                 return;
         }
@@ -314,9 +315,11 @@ void dasd_alias_disconnect_device_from_lcu(struct dasd_device *device)
         struct alias_lcu *lcu;
         struct alias_server *server;
         int was_pending;
+        struct dasd_uid uid;
 
         private = (struct dasd_eckd_private *) device->private;
         lcu = private->lcu;
+        device->discipline->get_uid(device, &uid);
         spin_lock_irqsave(&lcu->lock, flags);
         list_del_init(&device->alias_list);
         /* make sure that the workers don't use this device */
@@ -353,7 +356,7 @@ void dasd_alias_disconnect_device_from_lcu(struct dasd_device *device)
                         _schedule_lcu_update(lcu, NULL);
                 spin_unlock(&lcu->lock);
         }
-        server = _find_server(&private->uid);
+        server = _find_server(&uid);
         if (server && list_empty(&server->lculist)) {
                 list_del(&server->server);
                 _free_server(server);
@@ -366,19 +369,30 @@ void dasd_alias_disconnect_device_from_lcu(struct dasd_device *device)
  * in the lcu is up to date and will update the device uid before
  * adding it to a pav group.
  */
+
 static int _add_device_to_lcu(struct alias_lcu *lcu,
-                              struct dasd_device *device)
+                              struct dasd_device *device,
+                              struct dasd_device *pos)
 {
 
         struct dasd_eckd_private *private;
         struct alias_pav_group *group;
-        struct dasd_uid *uid;
+        struct dasd_uid uid;
+        unsigned long flags;
 
         private = (struct dasd_eckd_private *) device->private;
-        uid = &private->uid;
-        uid->type = lcu->uac->unit[uid->real_unit_addr].ua_type;
-        uid->base_unit_addr = lcu->uac->unit[uid->real_unit_addr].base_ua;
-        dasd_set_uid(device->cdev, &private->uid);
+
+        /* only lock if not already locked */
+        if (device != pos)
+                spin_lock_irqsave_nested(get_ccwdev_lock(device->cdev), flags,
+                                         CDEV_NESTED_SECOND);
+        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;
+
+        if (device != pos)
+                spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
 
         /* if we have no PAV anyway, we don't need to bother with PAV groups */
         if (lcu->pav == NO_PAV) {
@@ -386,25 +400,25 @@ static int _add_device_to_lcu(struct alias_lcu *lcu,
                 return 0;
         }
 
-        group = _find_group(lcu, uid);
+        group = _find_group(lcu, &uid);
         if (!group) {
                 group = kzalloc(sizeof(*group), GFP_ATOMIC);
                 if (!group)
                         return -ENOMEM;
-                memcpy(group->uid.vendor, uid->vendor, sizeof(uid->vendor));
-                memcpy(group->uid.serial, uid->serial, sizeof(uid->serial));
-                group->uid.ssid = uid->ssid;
-                if (uid->type == UA_BASE_DEVICE)
-                        group->uid.base_unit_addr = uid->real_unit_addr;
+                memcpy(group->uid.vendor, uid.vendor, sizeof(uid.vendor));
+                memcpy(group->uid.serial, uid.serial, sizeof(uid.serial));
+                group->uid.ssid = uid.ssid;
+                if (uid.type == UA_BASE_DEVICE)
+                        group->uid.base_unit_addr = uid.real_unit_addr;
                 else
-                        group->uid.base_unit_addr = uid->base_unit_addr;
-                memcpy(group->uid.vduit, uid->vduit, sizeof(uid->vduit));
+                        group->uid.base_unit_addr = uid.base_unit_addr;
+                memcpy(group->uid.vduit, uid.vduit, sizeof(uid.vduit));
                 INIT_LIST_HEAD(&group->group);
                 INIT_LIST_HEAD(&group->baselist);
                 INIT_LIST_HEAD(&group->aliaslist);
                 list_add(&group->group, &lcu->grouplist);
         }
-        if (uid->type == UA_BASE_DEVICE)
+        if (uid.type == UA_BASE_DEVICE)
                 list_move(&device->alias_list, &group->baselist);
         else
                 list_move(&device->alias_list, &group->aliaslist);
@@ -525,7 +539,10 @@ static int _lcu_update(struct dasd_device *refdev, struct alias_lcu *lcu)
         if (rc)
                 return rc;
 
-        spin_lock_irqsave(&lcu->lock, flags);
+        /* need to take cdev lock before lcu lock */
+        spin_lock_irqsave_nested(get_ccwdev_lock(refdev->cdev), flags,
+                                 CDEV_NESTED_FIRST);
+        spin_lock(&lcu->lock);
         lcu->pav = NO_PAV;
         for (i = 0; i < MAX_DEVICES_PER_LCU; ++i) {
                 switch (lcu->uac->unit[i].ua_type) {
@@ -542,9 +559,10 @@ static int _lcu_update(struct dasd_device *refdev, struct alias_lcu *lcu)
 
         list_for_each_entry_safe(device, tempdev, &lcu->active_devices,
                                  alias_list) {
-                _add_device_to_lcu(lcu, device);
+                _add_device_to_lcu(lcu, device, refdev);
         }
-        spin_unlock_irqrestore(&lcu->lock, flags);
+        spin_unlock(&lcu->lock);
+        spin_unlock_irqrestore(get_ccwdev_lock(refdev->cdev), flags);
         return 0;
 }
 
@@ -628,9 +646,12 @@ int dasd_alias_add_device(struct dasd_device *device)
         private = (struct dasd_eckd_private *) device->private;
         lcu = private->lcu;
         rc = 0;
-        spin_lock_irqsave(&lcu->lock, flags);
+
+        /* need to take cdev lock before lcu lock */
+        spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
+        spin_lock(&lcu->lock);
         if (!(lcu->flags & UPDATE_PENDING)) {
-                rc = _add_device_to_lcu(lcu, device);
+                rc = _add_device_to_lcu(lcu, device, device);
                 if (rc)
                         lcu->flags |= UPDATE_PENDING;
         }
@@ -638,7 +659,8 @@ int dasd_alias_add_device(struct dasd_device *device)
                 list_move(&device->alias_list, &lcu->active_devices);
                 _schedule_lcu_update(lcu, device);
         }
-        spin_unlock_irqrestore(&lcu->lock, flags);
+        spin_unlock(&lcu->lock);
+        spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
         return rc;
 }
 
@@ -748,19 +770,30 @@ static void _restart_all_base_devices_on_lcu(struct alias_lcu *lcu)
         struct alias_pav_group *pavgroup;
         struct dasd_device *device;
         struct dasd_eckd_private *private;
+        unsigned long flags;
 
         /* active and inactive list can contain alias as well as base devices */
         list_for_each_entry(device, &lcu->active_devices, alias_list) {
                 private = (struct dasd_eckd_private *) device->private;
-                if (private->uid.type != UA_BASE_DEVICE)
+                spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
+                if (private->uid.type != UA_BASE_DEVICE) {
+                        spin_unlock_irqrestore(get_ccwdev_lock(device->cdev),
+                                               flags);
                         continue;
+                }
+                spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
                 dasd_schedule_block_bh(device->block);
                 dasd_schedule_device_bh(device);
         }
         list_for_each_entry(device, &lcu->inactive_devices, alias_list) {
                 private = (struct dasd_eckd_private *) device->private;
-                if (private->uid.type != UA_BASE_DEVICE)
+                spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
+                if (private->uid.type != UA_BASE_DEVICE) {
+                        spin_unlock_irqrestore(get_ccwdev_lock(device->cdev),
+                                               flags);
                         continue;
+                }
+                spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
                 dasd_schedule_block_bh(device->block);
                 dasd_schedule_device_bh(device);
         }
diff --git a/drivers/s390/block/dasd_devmap.c b/drivers/s390/block/dasd_devmap.c
index eff9c812c5c2..34d51dd4c539 100644
--- a/drivers/s390/block/dasd_devmap.c
+++ b/drivers/s390/block/dasd_devmap.c
@@ -49,7 +49,6 @@ struct dasd_devmap {
         unsigned int devindex;
         unsigned short features;
         struct dasd_device *device;
-        struct dasd_uid uid;
 };
 
 /*
@@ -936,42 +935,46 @@ dasd_device_status_show(struct device *dev, struct device_attribute *attr,
 
 static DEVICE_ATTR(status, 0444, dasd_device_status_show, NULL);
 
-static ssize_t
-dasd_alias_show(struct device *dev, struct device_attribute *attr, char *buf)
+static ssize_t dasd_alias_show(struct device *dev,
+                               struct device_attribute *attr, char *buf)
 {
-        struct dasd_devmap *devmap;
-        int alias;
+        struct dasd_device *device;
+        struct dasd_uid uid;
 
-        devmap = dasd_find_busid(dev_name(dev));
-        spin_lock(&dasd_devmap_lock);
-        if (IS_ERR(devmap) || strlen(devmap->uid.vendor) == 0) {
-                spin_unlock(&dasd_devmap_lock);
+        device = dasd_device_from_cdev(to_ccwdev(dev));
+        if (IS_ERR(device))
                 return sprintf(buf, "0\n");
+
+        if (device->discipline && device->discipline->get_uid &&
+            !device->discipline->get_uid(device, &uid)) {
+                if (uid.type == UA_BASE_PAV_ALIAS ||
+                    uid.type == UA_HYPER_PAV_ALIAS)
+                        return sprintf(buf, "1\n");
         }
-        if (devmap->uid.type == UA_BASE_PAV_ALIAS ||
-            devmap->uid.type == UA_HYPER_PAV_ALIAS)
-                alias = 1;
-        else
-                alias = 0;
-        spin_unlock(&dasd_devmap_lock);
-        return sprintf(buf, alias ? "1\n" : "0\n");
+        dasd_put_device(device);
+
+        return sprintf(buf, "0\n");
 }
 
 static DEVICE_ATTR(alias, 0444, dasd_alias_show, NULL);
 
-static ssize_t
-dasd_vendor_show(struct device *dev, struct device_attribute *attr, char *buf)
+static ssize_t dasd_vendor_show(struct device *dev,
+                                struct device_attribute *attr, char *buf)
 {
-        struct dasd_devmap *devmap;
+        struct dasd_device *device;
+        struct dasd_uid uid;
         char *vendor;
 
-        devmap = dasd_find_busid(dev_name(dev));
-        spin_lock(&dasd_devmap_lock);
-        if (!IS_ERR(devmap) && strlen(devmap->uid.vendor) > 0)
-                vendor = devmap->uid.vendor;
-        else
-                vendor = "";
-        spin_unlock(&dasd_devmap_lock);
+        device = dasd_device_from_cdev(to_ccwdev(dev));
+        vendor = "";
+        if (IS_ERR(device))
+                return snprintf(buf, PAGE_SIZE, "%s\n", vendor);
+
+        if (device->discipline && device->discipline->get_uid &&
+            !device->discipline->get_uid(device, &uid))
+                        vendor = uid.vendor;
+
+        dasd_put_device(device);
 
         return snprintf(buf, PAGE_SIZE, "%s\n", vendor);
 }
@@ -985,48 +988,51 @@ static DEVICE_ATTR(vendor, 0444, dasd_vendor_show, NULL);
 static ssize_t
 dasd_uid_show(struct device *dev, struct device_attribute *attr, char *buf)
 {
-        struct dasd_devmap *devmap;
+        struct dasd_device *device;
+        struct dasd_uid uid;
         char uid_string[UID_STRLEN];
         char ua_string[3];
-        struct dasd_uid *uid;
 
-        devmap = dasd_find_busid(dev_name(dev));
-        spin_lock(&dasd_devmap_lock);
-        if (IS_ERR(devmap) || strlen(devmap->uid.vendor) == 0) {
-                spin_unlock(&dasd_devmap_lock);
-                return sprintf(buf, "\n");
-        }
-        uid = &devmap->uid;
-        switch (uid->type) {
-        case UA_BASE_DEVICE:
-                sprintf(ua_string, "%02x", uid->real_unit_addr);
-                break;
-        case UA_BASE_PAV_ALIAS:
-                sprintf(ua_string, "%02x", uid->base_unit_addr);
-                break;
-        case UA_HYPER_PAV_ALIAS:
-                sprintf(ua_string, "xx");
-                break;
-        default:
-                /* should not happen, treat like base device */
-                sprintf(ua_string, "%02x", uid->real_unit_addr);
-                break;
+        device = dasd_device_from_cdev(to_ccwdev(dev));
+        uid_string[0] = 0;
+        if (IS_ERR(device))
+                return snprintf(buf, PAGE_SIZE, "%s\n", uid_string);
+
+        if (device->discipline && device->discipline->get_uid &&
+            !device->discipline->get_uid(device, &uid)) {
+                switch (uid.type) {
+                case UA_BASE_DEVICE:
+                        snprintf(ua_string, sizeof(ua_string), "%02x",
+                                 uid.real_unit_addr);
+                        break;
+                case UA_BASE_PAV_ALIAS:
+                        snprintf(ua_string, sizeof(ua_string), "%02x",
+                                 uid.base_unit_addr);
+                        break;
+                case UA_HYPER_PAV_ALIAS:
+                        snprintf(ua_string, sizeof(ua_string), "xx");
+                        break;
+                default:
+                        /* should not happen, treat like base device */
+                        snprintf(ua_string, sizeof(ua_string), "%02x",
+                                 uid.real_unit_addr);
+                        break;
+                }
+
+                if (strlen(uid.vduit) > 0)
+                        snprintf(uid_string, sizeof(uid_string),
+                                 "%s.%s.%04x.%s.%s",
+                                 uid.vendor, uid.serial, uid.ssid, ua_string,
+                                 uid.vduit);
+                else
+                        snprintf(uid_string, sizeof(uid_string),
+                                 "%s.%s.%04x.%s",
+                                 uid.vendor, uid.serial, uid.ssid, ua_string);
         }
-        if (strlen(uid->vduit) > 0)
-                snprintf(uid_string, sizeof(uid_string),
-                         "%s.%s.%04x.%s.%s",
-                         uid->vendor, uid->serial,
-                         uid->ssid, ua_string,
-                         uid->vduit);
-        else
-                snprintf(uid_string, sizeof(uid_string),
-                         "%s.%s.%04x.%s",
-                         uid->vendor, uid->serial,
-                         uid->ssid, ua_string);
-        spin_unlock(&dasd_devmap_lock);
+        dasd_put_device(device);
+
         return snprintf(buf, PAGE_SIZE, "%s\n", uid_string);
 }
-
 static DEVICE_ATTR(uid, 0444, dasd_uid_show, NULL);
 
 /*
@@ -1094,50 +1100,6 @@ static struct attribute_group dasd_attr_group = {
 };
 
 /*
- * Return copy of the device unique identifier.
- */
-int
-dasd_get_uid(struct ccw_device *cdev, struct dasd_uid *uid)
-{
-        struct dasd_devmap *devmap;
-
-        devmap = dasd_find_busid(dev_name(&cdev->dev));
-        if (IS_ERR(devmap))
-                return PTR_ERR(devmap);
-        spin_lock(&dasd_devmap_lock);
-        *uid = devmap->uid;
-        spin_unlock(&dasd_devmap_lock);
-        return 0;
-}
-EXPORT_SYMBOL_GPL(dasd_get_uid);
-
-/*
- * Register the given device unique identifier into devmap struct.
- * In addition check if the related storage server subsystem ID is already
- * contained in the dasd_server_ssid_list. If subsystem ID is not contained,
- * create new entry.
- * Return 0 if server was already in serverlist,
- *        1 if the server was added successful
- *       <0 in case of error.
- */
-int
-dasd_set_uid(struct ccw_device *cdev, struct dasd_uid *uid)
-{
-        struct dasd_devmap *devmap;
-
-        devmap = dasd_find_busid(dev_name(&cdev->dev));
-        if (IS_ERR(devmap))
-                return PTR_ERR(devmap);
-
-        spin_lock(&dasd_devmap_lock);
-        devmap->uid = *uid;
-        spin_unlock(&dasd_devmap_lock);
-
-        return 0;
-}
-EXPORT_SYMBOL_GPL(dasd_set_uid);
-
-/*
  * Return value of the specified feature.
  */
 int
diff --git a/drivers/s390/block/dasd_eckd.c b/drivers/s390/block/dasd_eckd.c
index 4305c23c57a4..5b1cd8d6e971 100644
--- a/drivers/s390/block/dasd_eckd.c
+++ b/drivers/s390/block/dasd_eckd.c
@@ -692,18 +692,20 @@ dasd_eckd_cdl_reclen(int recid)
 /*
  * Generate device unique id that specifies the physical device.
  */
-static int dasd_eckd_generate_uid(struct dasd_device *device,
-                                  struct dasd_uid *uid)
+static int dasd_eckd_generate_uid(struct dasd_device *device)
 {
         struct dasd_eckd_private *private;
+        struct dasd_uid *uid;
         int count;
+        unsigned long flags;
 
         private = (struct dasd_eckd_private *) device->private;
         if (!private)
                 return -ENODEV;
         if (!private->ned || !private->gneq)
                 return -ENODEV;
-
+        uid = &private->uid;
+        spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
         memset(uid, 0, sizeof(struct dasd_uid));
         memcpy(uid->vendor, private->ned->HDA_manufacturer,
                sizeof(uid->vendor) - 1);
@@ -726,9 +728,25 @@ static int dasd_eckd_generate_uid(struct dasd_device *device,
                                 private->vdsneq->uit[count]);
                 }
         }
+        spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
         return 0;
 }
 
+static int dasd_eckd_get_uid(struct dasd_device *device, struct dasd_uid *uid)
+{
+        struct dasd_eckd_private *private;
+        unsigned long flags;
+
+        if (device->private) {
+                private = (struct dasd_eckd_private *)device->private;
+                spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
+                *uid = private->uid;
+                spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
+                return 0;
+        }
+        return -EINVAL;
+}
+
 static struct dasd_ccw_req *dasd_eckd_build_rcd_lpm(struct dasd_device *device,
                                                     void *rcd_buffer,
                                                     struct ciw *ciw, __u8 lpm)
@@ -1088,6 +1106,7 @@ dasd_eckd_check_characteristics(struct dasd_device *device)
 {
         struct dasd_eckd_private *private;
         struct dasd_block *block;
+        struct dasd_uid temp_uid;
         int is_known, rc;
         int readonly;
 
@@ -1124,13 +1143,13 @@ dasd_eckd_check_characteristics(struct dasd_device *device)
         if (rc)
                 goto out_err1;
 
-        /* Generate device unique id and register in devmap */
-        rc = dasd_eckd_generate_uid(device, &private->uid);
+        /* Generate device unique id */
+        rc = dasd_eckd_generate_uid(device);
         if (rc)
                 goto out_err1;
-        dasd_set_uid(device->cdev, &private->uid);
 
-        if (private->uid.type == UA_BASE_DEVICE) {
+        dasd_eckd_get_uid(device, &temp_uid);
+        if (temp_uid.type == UA_BASE_DEVICE) {
                 block = dasd_alloc_block();
                 if (IS_ERR(block)) {
                         DBF_EVENT_DEVID(DBF_WARNING, device->cdev, "%s",
@@ -3305,15 +3324,16 @@ static int dasd_eckd_restore_device(struct dasd_device *device)
         if (rc)
                 goto out_err;
 
-        /* Generate device unique id and register in devmap */
-        rc = dasd_eckd_generate_uid(device, &private->uid);
-        dasd_get_uid(device->cdev, &temp_uid);
+        dasd_eckd_get_uid(device, &temp_uid);
+        /* Generate device unique id */
+        rc = dasd_eckd_generate_uid(device);
+        spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
         if (memcmp(&private->uid, &temp_uid, sizeof(struct dasd_uid)) != 0)
                 dev_err(&device->cdev->dev, "The UID of the DASD has "
                         "changed\n");
+        spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
         if (rc)
                 goto out_err;
-        dasd_set_uid(device->cdev, &private->uid);
 
         /* register lcu with alias handling, enable PAV if this is a new lcu */
         is_known = dasd_alias_make_device_known_to_lcu(device);
@@ -3358,42 +3378,45 @@ static int dasd_eckd_reload_device(struct dasd_device *device)
 {
         struct dasd_eckd_private *private;
         int rc, old_base;
-        char uid[60];
+        char print_uid[60];
+        struct dasd_uid uid;
+        unsigned long flags;
 
         private = (struct dasd_eckd_private *) device->private;
+
+        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);
+
         /* Read Configuration Data */
         rc = dasd_eckd_read_conf(device);
         if (rc)
                 goto out_err;
 
-        rc = dasd_eckd_generate_uid(device, &private->uid);
+        rc = dasd_eckd_generate_uid(device);
         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);
+        dasd_eckd_get_uid(device, &uid);
+
+        if (old_base != uid.base_unit_addr) {
+                if (strlen(uid.vduit) > 0)
+                        snprintf(print_uid, sizeof(print_uid),
+                                 "%s.%s.%04x.%02x.%s", uid.vendor, uid.serial,
+                                 uid.ssid, uid.base_unit_addr, uid.vduit);
                 else
-                        snprintf(uid, 60, "%s.%s.%04x.%02x",
-                                 private->uid.vendor, private->uid.serial,
-                                 private->uid.ssid,
-                                 private->uid.base_unit_addr);
+                        snprintf(print_uid, sizeof(print_uid),
+                                 "%s.%s.%04x.%02x", uid.vendor, uid.serial,
+                                 uid.ssid, uid.base_unit_addr);
 
                 dev_info(&device->cdev->dev,
                          "An Alias device was reassigned to a new base device "
-                         "with UID: %s\n", uid);
+                         "with UID: %s\n", print_uid);
         }
         return 0;
 
@@ -3455,6 +3478,7 @@ static struct dasd_discipline dasd_eckd_discipline = {
         .freeze = dasd_eckd_pm_freeze,
         .restore = dasd_eckd_restore_device,
         .reload = dasd_eckd_reload_device,
+        .get_uid = dasd_eckd_get_uid,
 };
 
 static int __init
diff --git a/drivers/s390/block/dasd_int.h b/drivers/s390/block/dasd_int.h
index 1ae7b121628e..32fac186ba3f 100644
--- a/drivers/s390/block/dasd_int.h
+++ b/drivers/s390/block/dasd_int.h
@@ -81,6 +81,10 @@ struct dasd_block;
 #define DASD_SIM_MSG_TO_OP 0x03
 #define DASD_SIM_LOG 0x0C
 
+/* lock class for nested cdev lock */
+#define CDEV_NESTED_FIRST 1
+#define CDEV_NESTED_SECOND 2
+
 /*
  * SECTION: MACROs for klogd and s390 debug feature (dbf)
  */
@@ -229,6 +233,24 @@ struct dasd_ccw_req {
 typedef struct dasd_ccw_req *(*dasd_erp_fn_t) (struct dasd_ccw_req *);
 
 /*
+ * Unique identifier for dasd device.
+ */
+#define UA_NOT_CONFIGURED  0x00
+#define UA_BASE_DEVICE     0x01
+#define UA_BASE_PAV_ALIAS  0x02
+#define UA_HYPER_PAV_ALIAS 0x03
+
+struct dasd_uid {
+        __u8 type;
+        char vendor[4];
+        char serial[15];
+        __u16 ssid;
+        __u8 real_unit_addr;
+        __u8 base_unit_addr;
+        char vduit[33];
+};
+
+/*
  * the struct dasd_discipline is
  * sth like a table of virtual functions, if you think of dasd_eckd
  * inheriting dasd...
@@ -315,29 +337,13 @@ struct dasd_discipline {
 
         /* reload device after state change */
         int (*reload) (struct dasd_device *);
+
+        int (*get_uid) (struct dasd_device *, struct dasd_uid *);
 };
 
 extern struct dasd_discipline *dasd_diag_discipline_pointer;
 
 /*
- * Unique identifier for dasd device.
- */
-#define UA_NOT_CONFIGURED  0x00
-#define UA_BASE_DEVICE     0x01
-#define UA_BASE_PAV_ALIAS  0x02
-#define UA_HYPER_PAV_ALIAS 0x03
-
-struct dasd_uid {
-        __u8 type;
-        char vendor[4];
-        char serial[15];
-        __u16 ssid;
-        __u8 real_unit_addr;
-        __u8 base_unit_addr;
-        char vduit[33];
-};
-
-/*
  * Notification numbers for extended error reporting notifications:
  * The DASD_EER_DISABLE notification is sent before a dasd_device (and it's
  * eer pointer) is freed. The error reporting module needs to do all necessary
@@ -634,8 +640,6 @@ void dasd_devmap_exit(void);
 struct dasd_device *dasd_create_device(struct ccw_device *);
 void dasd_delete_device(struct dasd_device *);
 
-int dasd_get_uid(struct ccw_device *, struct dasd_uid *);
-int dasd_set_uid(struct ccw_device *, struct dasd_uid *);
 int dasd_get_feature(struct ccw_device *, int);
 int dasd_set_feature(struct ccw_device *, int, int);