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authorStefan Weinhuber <wein@de.ibm.com>2008-01-26 14:11:23 +0100
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2008-01-26 14:11:28 +0100
commit8e09f21574ea3028d5629e5de759e0b196c690c5 (patch)
treeced4feb1847ee6c2a7b7b4cec8f3118f83d3a386 /drivers/s390/block/dasd_devmap.c
parent0ac30be461084f30ad6e22c6b91347e880ed41aa (diff)
[S390] dasd: add hyper PAV support to DASD device driver, part 1
Parallel access volumes (PAV) is a storage server feature, that allows to start multiple channel programs on the same DASD in parallel. It defines alias devices which can be used as alternative paths to the same disk. With the old base PAV support we only needed rudimentary functionality in the DASD device driver. As the mapping between base and alias devices was static, we just had to export an identifier (uid) and could leave the combining of devices to external layers like a device mapper multipath. Now hyper PAV removes the requirement to dedicate alias devices to specific base devices. Instead each alias devices can be combined with multiple base device on a per request basis. This requires full support by the DASD device driver as now each channel program itself has to identify the target base device. The changes to the dasd device driver and the ECKD discipline are: - Separate subchannel device representation (dasd_device) from block device representation (dasd_block). Only base devices are block devices. - Gather information about base and alias devices and possible combinations. - For each request decide which dasd_device should be used (base or alias) and build specific channel program. - Support summary unit checks, which allow the storage server to upgrade / downgrade between base and hyper PAV at runtime (support is mandatory). Signed-off-by: Stefan Weinhuber <wein@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'drivers/s390/block/dasd_devmap.c')
-rw-r--r--drivers/s390/block/dasd_devmap.c94
1 files changed, 37 insertions, 57 deletions
diff --git a/drivers/s390/block/dasd_devmap.c b/drivers/s390/block/dasd_devmap.c
index 0c67258fb9e..f4fb4025734 100644
--- a/drivers/s390/block/dasd_devmap.c
+++ b/drivers/s390/block/dasd_devmap.c
@@ -49,22 +49,6 @@ struct dasd_devmap {
};
/*
- * dasd_server_ssid_map contains a globally unique storage server subsystem ID.
- * dasd_server_ssid_list contains the list of all subsystem IDs accessed by
- * the DASD device driver.
- */
-struct dasd_server_ssid_map {
- struct list_head list;
- struct system_id {
- char vendor[4];
- char serial[15];
- __u16 ssid;
- } sid;
-};
-
-static struct list_head dasd_server_ssid_list;
-
-/*
* Parameter parsing functions for dasd= parameter. The syntax is:
* <devno> : (0x)?[0-9a-fA-F]+
* <busid> : [0-0a-f]\.[0-9a-f]\.(0x)?[0-9a-fA-F]+
@@ -721,8 +705,9 @@ dasd_ro_store(struct device *dev, struct device_attribute *attr,
devmap->features &= ~DASD_FEATURE_READONLY;
if (devmap->device)
devmap->device->features = devmap->features;
- if (devmap->device && devmap->device->gdp)
- set_disk_ro(devmap->device->gdp, val);
+ if (devmap->device && devmap->device->block
+ && devmap->device->block->gdp)
+ set_disk_ro(devmap->device->block->gdp, val);
spin_unlock(&dasd_devmap_lock);
return count;
}
@@ -893,12 +878,16 @@ dasd_alias_show(struct device *dev, struct device_attribute *attr, char *buf)
devmap = dasd_find_busid(dev->bus_id);
spin_lock(&dasd_devmap_lock);
- if (!IS_ERR(devmap))
- alias = devmap->uid.alias;
+ if (IS_ERR(devmap) || strlen(devmap->uid.vendor) == 0) {
+ spin_unlock(&dasd_devmap_lock);
+ return sprintf(buf, "0\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");
}
@@ -930,19 +919,36 @@ static ssize_t
dasd_uid_show(struct device *dev, struct device_attribute *attr, char *buf)
{
struct dasd_devmap *devmap;
- char uid[UID_STRLEN];
+ char uid_string[UID_STRLEN];
+ char ua_string[3];
+ struct dasd_uid *uid;
devmap = dasd_find_busid(dev->bus_id);
spin_lock(&dasd_devmap_lock);
- if (!IS_ERR(devmap) && strlen(devmap->uid.vendor) > 0)
- snprintf(uid, sizeof(uid), "%s.%s.%04x.%02x",
- devmap->uid.vendor, devmap->uid.serial,
- devmap->uid.ssid, devmap->uid.unit_addr);
- else
- uid[0] = 0;
+ 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;
+ }
+ snprintf(uid_string, sizeof(uid_string), "%s.%s.%04x.%s",
+ uid->vendor, uid->serial, uid->ssid, ua_string);
spin_unlock(&dasd_devmap_lock);
-
- return snprintf(buf, PAGE_SIZE, "%s\n", uid);
+ return snprintf(buf, PAGE_SIZE, "%s\n", uid_string);
}
static DEVICE_ATTR(uid, 0444, dasd_uid_show, NULL);
@@ -1040,39 +1046,16 @@ int
dasd_set_uid(struct ccw_device *cdev, struct dasd_uid *uid)
{
struct dasd_devmap *devmap;
- struct dasd_server_ssid_map *srv, *tmp;
devmap = dasd_find_busid(cdev->dev.bus_id);
if (IS_ERR(devmap))
return PTR_ERR(devmap);
- /* generate entry for server_ssid_map */
- srv = (struct dasd_server_ssid_map *)
- kzalloc(sizeof(struct dasd_server_ssid_map), GFP_KERNEL);
- if (!srv)
- return -ENOMEM;
- strncpy(srv->sid.vendor, uid->vendor, sizeof(srv->sid.vendor) - 1);
- strncpy(srv->sid.serial, uid->serial, sizeof(srv->sid.serial) - 1);
- srv->sid.ssid = uid->ssid;
-
- /* server is already contained ? */
spin_lock(&dasd_devmap_lock);
devmap->uid = *uid;
- list_for_each_entry(tmp, &dasd_server_ssid_list, list) {
- if (!memcmp(&srv->sid, &tmp->sid,
- sizeof(struct system_id))) {
- kfree(srv);
- srv = NULL;
- break;
- }
- }
-
- /* add servermap to serverlist */
- if (srv)
- list_add(&srv->list, &dasd_server_ssid_list);
spin_unlock(&dasd_devmap_lock);
- return (srv ? 1 : 0);
+ return 0;
}
EXPORT_SYMBOL_GPL(dasd_set_uid);
@@ -1138,9 +1121,6 @@ dasd_devmap_init(void)
dasd_max_devindex = 0;
for (i = 0; i < 256; i++)
INIT_LIST_HEAD(&dasd_hashlists[i]);
-
- /* Initialize servermap structure. */
- INIT_LIST_HEAD(&dasd_server_ssid_list);
return 0;
}