// SPDX-License-Identifier: GPL-2.0
/*
* PAV alias management for the DASD ECKD discipline
*
* Copyright IBM Corp. 2007
* Author(s): Stefan Weinhuber <[email protected]>
*/
#include <linux/list.h>
#include <linux/slab.h>
#include <asm/ebcdic.h>
#include "dasd_int.h"
#include "dasd_eckd.h"
/*
* General concept of alias management:
* - PAV and DASD alias management is specific to the eckd discipline.
* - A device is connected to an lcu as long as the device exists.
* dasd_alias_make_device_known_to_lcu will be called wenn the
* device is checked by the eckd discipline and
* dasd_alias_disconnect_device_from_lcu will be called
* before the device is deleted.
* - The dasd_alias_add_device / dasd_alias_remove_device
* functions mark the point when a device is 'ready for service'.
* - A summary unit check is a rare occasion, but it is mandatory to
* support it. It requires some complex recovery actions before the
* devices can be used again (see dasd_alias_handle_summary_unit_check).
* - dasd_alias_get_start_dev will find an alias device that can be used
* instead of the base device and does some (very simple) load balancing.
* This is the function that gets called for each I/O, so when improving
* something, this function should get faster or better, the rest has just
* to be correct.
*/
static void summary_unit_check_handling_work(struct work_struct *);
static void lcu_update_work(struct work_struct *);
static int _schedule_lcu_update(struct alias_lcu *, struct dasd_device *);
static struct alias_root aliastree = {
.serverlist = LIST_HEAD_INIT(aliastree.serverlist),
.lock = __SPIN_LOCK_UNLOCKED(aliastree.lock),
};
static struct alias_server *_find_server(struct dasd_uid *uid)
{
struct alias_server *pos;
list_for_each_entry(pos, &aliastree.serverlist, server) {
if (!strncmp(pos->uid.vendor, uid->vendor,
sizeof(uid->vendor))
&& !strncmp(pos->uid.serial, uid->serial,
sizeof(uid->serial)))
return pos;
}
return NULL;
}
static struct alias_lcu *_find_lcu(struct alias_server *server,
struct dasd_uid *uid)
{
struct alias_lcu *pos;
list_for_each_entry(pos, &server->lculist, lcu) {
if (pos->uid.ssid == uid->ssid)
return pos;
}
return NULL;
}
static struct alias_pav_group *_find_group(struct alias_lcu *lcu,
struct dasd_uid *uid)
{
struct alias_pav_group *pos;
__u8 search_unit_addr;
/* for hyper pav there is only one group */
if (lcu->pav == HYPER_PAV) {
if (list_empty(&lcu->grouplist))
return NULL;
else
return list_first_entry(&lcu->grouplist,
struct alias_pav_group, group);
}
/* for base pav we have to find the group that matches the base */
if (uid->type == UA_BASE_DEVICE)
search_unit_addr = uid->real_unit_addr;
else
search_unit_addr = uid->base_unit_addr;
list_for_each_entry(pos, &lcu->grouplist, group) {
if (pos->uid.base_unit_addr == search_unit_addr &&
!strncmp(pos->uid.vduit, uid->vduit, sizeof(uid->vduit)))
return pos;
}
return NULL;
}
static struct alias_server *_allocate_server(struct dasd_uid *uid)
{
struct alias_server *server;
server = kzalloc(sizeof(*server), GFP_KERNEL);
if (!server)
return ERR_PTR(-ENOMEM);
memcpy(server->uid.vendor, uid->vendor, sizeof(uid->vendor));
memcpy(server->uid.serial, uid->serial, sizeof(uid->serial));
INIT_LIST_HEAD(&server->server);
INIT_LIST_HEAD(&server->lculist);
return server;
}
static void _free_server(struct alias_server *server)
{
kfree(server);
}
static struct alias_lcu *_allocate_lcu(struct dasd_uid *uid)
{
struct alias_lcu *lcu;
lcu = kzalloc(sizeof(*lcu), GFP_KERNEL);
if (!lcu)
return ERR_PTR(-ENOMEM);
lcu->uac = kzalloc(sizeof(*(lcu->uac)), GFP_KERNEL | GFP_DMA);
if (!lcu->uac)
goto out_err1;
lcu->rsu_cqr = kzalloc(sizeof(*lcu->rsu_cqr), GFP_KERNEL | GFP_DMA);
if (!lcu->rsu_cqr)
goto out_err2;
lcu->rsu_cqr->cpaddr = kzalloc(sizeof(struct ccw1),
GFP_KERNEL | GFP_DMA);
if (!lcu->rsu_cqr->cpaddr)
goto out_err3;
lcu->rsu_cqr->data = kzalloc(16, GFP_KERNEL | GFP_DMA);
if (!lcu->rsu_cqr->data)
goto out_err4;
memcpy(lcu->uid.vendor, uid->vendor, sizeof(uid->vendor));
memcpy(lcu->uid.serial, uid->serial, sizeof(uid->serial));
lcu->uid.ssid = uid->ssid;
lcu->pav = NO_PAV;
lcu->flags = NEED_UAC_UPDATE | UPDATE_PENDING;
INIT_LIST_HEAD(&lcu->lcu);
INIT_LIST_HEAD(&lcu->inactive_devices);
INIT_LIST_HEAD(&lcu->active_devices);
INIT_LIST_HEAD(&lcu->grouplist);
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:
kfree(lcu->rsu_cqr->cpaddr);
out_err3:
kfree(lcu->rsu_cqr);
out_err2:
kfree(lcu->uac);
out_err1:
kfree(lcu);
return ERR_PTR(-ENOMEM);
}
static void _free_lcu(struct alias_lcu *lcu)
{
kfree(lcu->rsu_cqr->data);
kfree(lcu->rsu_cqr->cpaddr);
kfree(lcu->rsu_cqr);
kfree(lcu->uac);
kfree(lcu);
}
/*
* This is the function that will allocate all the server and lcu data,
* so this function must be called first for a new device.
* If the return value is 1, the lcu was already known before, if it
* is 0, this is a new lcu.
* Negative return code indicates that something went wrong (e.g. -ENOMEM)
*/
int dasd_alias_make_device_known_to_lcu(struct dasd_device *device)
{
struct dasd_eckd_private *private = device->private;
unsigned long flags;
struct alias_server *server, *newserver;
struct alias_lcu *lcu, *newlcu;
struct dasd_uid uid;
device->discipline->get_uid(device, &uid);
spin_lock_irqsave(&aliastree.lock, flags);
server = _find_server(&uid);
if (!server) {
spin_unlock_irqrestore(&aliastree.lock, flags);
newserver = _allocate_server(&uid);
if (IS_ERR(newserver))
return PTR_ERR(newserver);
spin_lock_irqsave(&aliastree.lock, flags);
server = _find_server(&uid);
if (!server) {
list_add(&newserver->server, &aliastree.serverlist);
server = newserver;
} else {
/* someone was faster */
_free_server(newserver);
}
}
lcu = _find_lcu(server, &uid);
if (!lcu) {
spin_unlock_irqrestore(&aliastree.lock, flags);
newlcu = _allocate_lcu(&uid);
if (IS_ERR(newlcu))
return PTR_ERR(newlcu);
spin_lock_irqsave(&aliastree.lock, flags);
lcu = _find_lcu(server, &uid);
if (!lcu) {
list_add(&newlcu->lcu, &server->lculist);
lcu = newlcu;
} else {
/* someone was faster */
_free_lcu(newlcu);
}
}
spin_lock(&lcu->lock);
list_add(&device->alias_list, &lcu->inactive_devices);
private->lcu = lcu;
spin_unlock(&lcu->lock);
spin_unlock_irqrestore(&aliastree.lock, flags);
return 0;
}
/*
* 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.
*/
void dasd_alias_disconnect_device_from_lcu(struct dasd_device *device)
{
struct dasd_eckd_private *private = device->private;
unsigned long flags;
struct alias_lcu *lcu;
struct alias_server *server;
int was_pending;
struct dasd_uid uid;
lcu = private->lcu;
/* nothing to do if already disconnected */
if (!lcu)
return;
device->discipline->get_uid(device, &uid);
spin_lock_irqsave(&lcu->lock, flags);
/* make sure that the workers don't use this device */
if (device == lcu->suc_data.device) {
spin_unlock_irqrestore(&lcu->lock, flags);
cancel_work_sync(&lcu->suc_data.worker);
spin_lock_irqsave(&lcu->lock, flags);
if (device == lcu->suc_data.device) {
dasd_put_device(device);
lcu->suc_data.device = NULL;
}
}
was_pending = 0;
if (device == lcu->ruac_data.device) {
spin_unlock_irqrestore(&lcu->lock, flags);
was_pending = 1;
cancel_delayed_work_sync(&lcu->ruac_data.dwork);
spin_lock_irqsave(&lcu->lock, flags);
if (device == lcu->ruac_data.device) {
dasd_put_device(device);
lcu->ruac_data.device = NULL;
}
}
private->lcu = NULL;
spin_unlock_irqrestore(&lcu->lock, flags);
spin_lock_irqsave(&aliastree.lock, flags);
spin_lock(&lcu->lock);
list_del_init(&device->alias_list);
if (list_empty(&lcu->grouplist) &&
list_empty(&lcu->active_devices) &&
list_empty(&lcu->inactive_devices)) {
list_del(&lcu->lcu);
spin_unlock(&lcu->lock);
_free_lcu(lcu);
lcu = NULL;
} else {
if (was_pending)
_schedule_lcu_update(lcu, NULL);
spin_unlock(&lcu->lock);
}
server = _find_server(&uid);
if (server && list_empty(&server->lculist)) {
list_del(&server->server);
_free_server(server);
}
spin_unlock_irqrestore(&aliastree.lock, flags);
}
/*
* This function assumes that the unit address configuration stored
* 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 *pos)
{
struct dasd_eckd_private *private = device->private;
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);
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;
else
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)
list_move(&device->alias_list, &group->baselist);
else
list_move(&device->alias_list, &group->aliaslist);
private->pavgroup = group;
return 0;
};
static void _remove_device_from_lcu(struct alias_lcu *lcu,
struct dasd_device *device)
{
struct dasd_eckd_private *private = device->private;
struct alias_pav_group *group;
list_move(&device->alias_list, &lcu->inactive_devices);
group = private->pavgroup;
if (!group)
return;
private->pavgroup = NULL;
if (list_empty(&group->baselist) && list_empty(&group->aliaslist)) {
list_del(&group->group);
kfree(group);
return;
}
if (group->next == device)
group->next = NULL;
};
static int
suborder_not_supported(struct dasd_ccw_req *cqr)
{
char *sense;
char reason;
char msg_format;
char msg_no;
/*
* intrc values ENODEV, ENOLINK and EPERM
* will be optained from sleep_on to indicate that no
* IO operation can be started
*/
if (cqr->intrc == -ENODEV)
return 1;
if (cqr->intrc == -ENOLINK)
return 1;
if (cqr->intrc == -EPERM)
return 1;
sense = dasd_get_sense(&cqr->irb);
if (!sense)
return 0;
reason = sense[0];
msg_format = (sense[7] & 0xF0);
msg_no = (sense[7] & 0x0F);
/* command reject, Format 0 MSG 4 - invalid parameter */
if ((reason == 0x80) && (msg_format == 0x00) && (msg_no == 0x04))
return 1;
return 0;
}
static int read_unit_address_configuration(struct dasd_device *device,
struct alias_lcu *lcu)
{
struct dasd_psf_prssd_data *prssdp;
struct dasd_ccw_req *cqr;
struct ccw1 *ccw;
int rc;
unsigned long flags;
cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, 1 /* PSF */ + 1 /* RSSD */,
(sizeof(struct dasd_psf_prssd_data)),
device, NULL);
if (IS_ERR(cqr))
return PTR_ERR(cqr);
cqr->startdev = device;
cqr->memdev = device;
clear_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags);
cqr->retries = 10;
cqr->expires = 20 * HZ;
/* Prepare for Read Subsystem Data */
prssdp = (struct dasd_psf_prssd_data *) cqr->data;
memset(prssdp, 0, sizeof(struct dasd_psf_prssd_data));
prssdp->order = PSF_ORDER_PRSSD;
prssdp->suborder = 0x0e; /* Read unit address configuration */
/* all other bytes of prssdp must be zero */
ccw = cqr->cpaddr;
ccw->cmd_code = DASD_ECKD_CCW_PSF;
ccw->count = sizeof(struct dasd_psf_prssd_data);
ccw->flags |= CCW_FLAG_CC;
ccw->cda = virt_to_dma32(prssdp);
/* Read Subsystem Data - feature codes */
memset(lcu->uac, 0, sizeof(*(lcu->uac)));
ccw++;
ccw->cmd_code = DASD_ECKD_CCW_RSSD;
ccw->count = sizeof(*(lcu->uac));
ccw->cda = virt_to_dma32(lcu->uac);
cqr->buildclk = get_tod_clock();
cqr->status = DASD_CQR_FILLED;
/* need to unset flag here to detect race with summary unit check */
spin_lock_irqsave(&lcu->lock, flags);
lcu->flags &= ~NEED_UAC_UPDATE;
spin_unlock_irqrestore(&lcu->lock, flags);
rc = dasd_sleep_on(cqr);
if (!rc)
goto out;
if (suborder_not_supported(cqr)) {
/* suborder not supported or device unusable for IO */
rc = -EOPNOTSUPP;
} else {
/* IO failed but should be retried */
spin_lock_irqsave(&lcu->lock, flags);
lcu->flags |= NEED_UAC_UPDATE;
spin_unlock_irqrestore(&lcu->lock, flags);
}
out:
dasd_sfree_request(cqr, cqr->memdev);
return rc;
}
static int _lcu_update(struct dasd_device *refdev, struct alias_lcu *lcu)
{
unsigned long flags;
struct alias_pav_group *pavgroup, *tempgroup;
struct dasd_device *device, *tempdev;
int i, rc;
struct dasd_eckd_private *private;
spin_lock_irqsave(&lcu->lock, flags);
list_for_each_entry_safe(pavgroup, tempgroup, &lcu->grouplist, group) {
list_for_each_entry_safe(device, tempdev, &pavgroup->baselist,
alias_list) {
list_move(&device->alias_list, &lcu->active_devices);
private = device->private;
private->pavgroup = NULL;
}
list_for_each_entry_safe(device, tempdev, &pavgroup->aliaslist,
alias_list) {
list_move(&device->alias_list, &lcu->active_devices);
private = device->private;
private->pavgroup = NULL;
}
list_del(&pavgroup->group);
kfree(pavgroup);
}
spin_unlock_irqrestore(&lcu->lock, flags);
rc = read_unit_address_configuration(refdev, lcu);
if (rc)
return rc;
spin_lock_irqsave(&lcu->lock, flags);
/*
* there is another update needed skip the remaining handling
* the data might already be outdated
* but especially do not add the device to an LCU with pending
* update
*/
if (lcu->flags & NEED_UAC_UPDATE)
goto out;
lcu->pav = NO_PAV;
for (i = 0; i < MAX_DEVICES_PER_LCU; ++i) {
switch (lcu->uac->unit[i].ua_type) {
case UA_BASE_PAV_ALIAS:
lcu->pav = BASE_PAV;
break;
case UA_HYPER_PAV_ALIAS:
lcu->pav = HYPER_PAV;
break;
}
if (lcu->pav != NO_PAV)
break;
}
list_for_each_entry_safe(device, tempdev, &lcu->active_devices,
alias_list) {
_add_device_to_lcu(lcu, device, refdev);
}
out:
spin_unlock_irqrestore(&lcu->lock, flags);
return 0;
}
static void lcu_update_work(struct work_struct *work)
{
struct alias_lcu *lcu;
struct read_uac_work_data *ruac_data;
struct dasd_device *device;
unsigned long flags;
int rc;
ruac_data = container_of(work, struct read_uac_work_data, dwork.work);
lcu = container_of(ruac_data, struct alias_lcu, ruac_data);
device = ruac_data->device;
rc = _lcu_update(device, lcu);
/*
* Need to check flags again, as there could have been another
* prepare_update or a new device a new device while we were still
* processing the data
*/
spin_lock_irqsave(&lcu->lock, flags);
if ((rc && (rc != -EOPNOTSUPP)) || (lcu->flags & NEED_UAC_UPDATE)) {
DBF_DEV_EVENT(DBF_WARNING, device, "could not update"
" alias data in lcu (rc = %d), retry later", rc);
if (!schedule_delayed_work(&lcu->ruac_data.dwork, 30*HZ))
dasd_put_device(device);
} else {
dasd_put_device(device);
lcu->ruac_data.device = NULL;
lcu->flags &= ~UPDATE_PENDING;
}
spin_unlock_irqrestore(&lcu->lock, flags);
}
static int _schedule_lcu_update(struct alias_lcu *lcu,
struct dasd_device *device)
{
struct dasd_device *usedev = NULL;
struct alias_pav_group *group;
lcu->flags |= NEED_UAC_UPDATE;
if (lcu->ruac_data.device) {
/* already scheduled or running */
return 0;
}
if (device && !list_empty(&device->alias_list))
usedev = device;
if (!usedev && !list_empty(&lcu->grouplist)) {
group = list_first_entry(&lcu->grouplist,
struct alias_pav_group, group);
if (!list_empty(&group->baselist))
usedev = list_first_entry(&group->baselist,
struct dasd_device,
alias_list);
else if (!list_empty(&group->aliaslist))
usedev = list_first_entry(&group->aliaslist,
struct dasd_device,
alias_list);
}
if (!usedev && !list_empty(&lcu->active_devices)) {
usedev = list_first_entry(&lcu->active_devices,
struct dasd_device, alias_list);
}
/*
* if we haven't found a proper device yet, give up for now, the next
* device that will be set active will trigger an lcu update
*/
if (!usedev)
return -EINVAL;
dasd_get_device(usedev);
lcu->ruac_data.device = usedev;
if (!schedule_delayed_work(&lcu->ruac_data.dwork, 0))
dasd_put_device(usedev);
return 0;
}
int dasd_alias_add_device(struct dasd_device *device)
{
struct dasd_eckd_private *private = device->private;
__u8 uaddr = private->uid.real_unit_addr;
struct alias_lcu *lcu = private->lcu;
unsigned long flags;
int rc;
rc = 0;
spin_lock_irqsave(&lcu->lock, flags);
/*
* Check if device and lcu type differ. If so, the uac data may be
* outdated and needs to be updated.
*/
if (private->uid.type != lcu->uac->unit[uaddr].ua_type) {
lcu->flags |= UPDATE_PENDING;
DBF_DEV_EVENT(DBF_WARNING, device, "%s",
"uid type mismatch - trigger rescan");
}
if (!(lcu->flags & UPDATE_PENDING)) {
rc = _add_device_to_lcu(lcu, device, device);
if (rc)
lcu->flags |= UPDATE_PENDING;
}
if (lcu->flags & UPDATE_PENDING) {
list_move(&device->alias_list, &lcu->active_devices);
private->pavgroup = NULL;
_schedule_lcu_update(lcu, device);
}
spin_unlock_irqrestore(&lcu->lock, flags);
return rc;
}
int dasd_alias_update_add_device(struct dasd_device *device)
{
struct dasd_eckd_private *private = device->private;
private->lcu->flags |= UPDATE_PENDING;
return dasd_alias_add_device(device);
}
int dasd_alias_remove_device(struct dasd_device *device)
{
struct dasd_eckd_private *private = device->private;
struct alias_lcu *lcu = private->lcu;
unsigned long flags;
/* nothing to do if already removed */
if (!lcu)
return 0;
spin_lock_irqsave(&lcu->lock, flags);
_remove_device_from_lcu(lcu, device);
spin_unlock_irqrestore(&lcu->lock, flags);
return 0;
}
struct dasd_device *dasd_alias_get_start_dev(struct dasd_device *base_device)
{
struct dasd_eckd_private *alias_priv, *private = base_device->private;
struct alias_lcu *lcu = private->lcu;
struct dasd_device *alias_device;
struct alias_pav_group *group;
unsigned long flags;
if (!lcu)
return NULL;
if (lcu->pav == NO_PAV ||
lcu->flags & (NEED_UAC_UPDATE | UPDATE_PENDING))
return NULL;
if (unlikely(!(private->features.feature[8] & 0x01))) {
/*
* PAV enabled but prefix not, very unlikely
* seems to be a lost pathgroup
* use base device to do IO
*/
DBF_DEV_EVENT(DBF_ERR, base_device, "%s",
"Prefix not enabled with PAV enabled\n");
return NULL;
}
spin_lock_irqsave(&lcu->lock, flags);
group = private->pavgroup;
if (!group) {
spin_unlock_irqrestore(&lcu->lock, flags);
return NULL;
}
alias_device = group->next;
if (!alias_device) {
if (list_empty(&group->aliaslist)) {
spin_unlock_irqrestore(&lcu->lock, flags);
return NULL;
} else {
alias_device = list_first_entry(&group->aliaslist,
struct dasd_device,
alias_list);
}
}
if (list_is_last(&alias_device->alias_list, &group->aliaslist))
group->next = list_first_entry(&group->aliaslist,
struct dasd_device, alias_list);
else
group->next = list_first_entry(&alias_device->alias_list,
struct dasd_device, alias_list);
spin_unlock_irqrestore(&lcu->lock, flags);
alias_priv = alias_device->private;
if ((alias_priv->count < private->count) && !alias_device->stopped &&
!test_bit(DASD_FLAG_OFFLINE, &alias_device->flags))
return alias_device;
else
return NULL;
}
/*
* Summary unit check handling depends on the way alias devices
* are handled so it is done here rather then in dasd_eckd.c
*/
static int reset_summary_unit_check(struct alias_lcu *lcu,
struct dasd_device *device,
char reason)
{
struct dasd_ccw_req *cqr;
int rc = 0;
struct ccw1 *ccw;
cqr = lcu->rsu_cqr;
memcpy((char *) &cqr->magic, "ECKD", 4);
ASCEBC((char *) &cqr->magic, 4);
ccw = cqr->cpaddr;
ccw->cmd_code = DASD_ECKD_CCW_RSCK;
ccw->flags = CCW_FLAG_SLI;
ccw->count = 16;
ccw->cda = virt_to_dma32(cqr->data);
((char *)cqr->data)[0] = reason;
clear_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags);
cqr->retries = 255; /* set retry counter to enable basic ERP */
cqr->startdev = device;
cqr->memdev = device;
cqr->block = NULL;
cqr->expires = 5 * HZ;
cqr->buildclk = get_tod_clock();
cqr->status = DASD_CQR_FILLED;
rc = dasd_sleep_on_immediatly(cqr);
return rc;
}
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;
/* active and inactive list can contain alias as well as base devices */
list_for_each_entry(device, &lcu->active_devices, alias_list) {
private = device->private;
if (private->uid.type != UA_BASE_DEVICE)
continue;
dasd_schedule_block_bh(device->block);
dasd_schedule_device_bh(device);
}
list_for_each_entry(device, &lcu->inactive_devices, alias_list) {
private = device->private;
if (private->uid.type != UA_BASE_DEVICE)
continue;
dasd_schedule_block_bh(device->block);
dasd_schedule_device_bh(device);
}
list_for_each_entry(pavgroup, &lcu->grouplist, group) {
list_for_each_entry(device, &pavgroup->baselist, alias_list) {
dasd_schedule_block_bh(device->block);
dasd_schedule_device_bh(device);
}
}
}
static void flush_all_alias_devices_on_lcu(struct alias_lcu *lcu)
{
struct alias_pav_group *pavgroup;
struct dasd_device *device, *temp;
struct dasd_eckd_private *private;
unsigned long flags;
LIST_HEAD(active);
/*
* Problem here ist that dasd_flush_device_queue may wait
* for termination of a request to complete. We can't keep
* the lcu lock during that time, so we must assume that
* the lists may have changed.
* Idea: first gather all active alias devices in a separate list,
* then flush the first element of this list unlocked, and afterwards
* check if it is still on the list before moving it to the
* active_devices list.
*/
spin_lock_irqsave(&lcu->lock, flags);
list_for_each_entry_safe(device, temp, &lcu->active_devices,
alias_list) {
private = device->private;
if (private->uid.type == UA_BASE_DEVICE)
continue;
list_move(&device->alias_list, &active);
}
list_for_each_entry(pavgroup, &lcu->grouplist, group) {
list_splice_init(&pavgroup->aliaslist, &active);
}
while (!list_empty(&active)) {
device = list_first_entry(&active, struct dasd_device,
alias_list);
spin_unlock_irqrestore(&lcu->lock, flags);
dasd_flush_device_queue(device);
spin_lock_irqsave(&lcu->lock, flags);
/*
* only move device around if it wasn't moved away while we
* were waiting for the flush
*/
if (device == list_first_entry(&active,
struct dasd_device, alias_list)) {
list_move(&device->alias_list, &lcu->active_devices);
private = device->private;
private->pavgroup = NULL;
}
}
spin_unlock_irqrestore(&lcu->lock, flags);
}
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) {
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(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) {
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(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));
}
}
}
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) {
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(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) {
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(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));
}
}
}
static void summary_unit_check_handling_work(struct work_struct *work)
{
struct alias_lcu *lcu;
struct summary_unit_check_work_data *suc_data;
unsigned long flags;
struct dasd_device *device;
suc_data = container_of(work, struct summary_unit_check_work_data,
worker);
lcu = container_of(suc_data, struct alias_lcu, suc_data);
device = suc_data->device;
/* 1. flush alias devices */
flush_all_alias_devices_on_lcu(lcu);
/* 2. reset summary unit check */
spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
dasd_device_remove_stop_bits(device,
(DASD_STOPPED_SU | DASD_STOPPED_PENDING));
spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
reset_summary_unit_check(lcu, device, suc_data->reason);
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);
spin_unlock_irqrestore(&lcu->lock, flags);
}
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;
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)");
goto out;
}
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
*/
if (list_empty(&device->alias_list)) {
DBF_DEV_EVENT(DBF_WARNING, device, "%s",
"device is in offline processing,"
" don't do summary unit check handling");
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");
goto out_unlock;
}
_stop_all_devices_on_lcu(lcu);
/* prepare for lcu_update */
lcu->flags |= NEED_UAC_UPDATE | UPDATE_PENDING;
lcu->suc_data.reason = private->suc_reason;
lcu->suc_data.device = device;
dasd_get_device(device);
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);
};
Codebase Browser
linux