--- /dev/null
+/*
+ * PAV alias management for the DASD ECKD discipline
+ *
+ * Copyright IBM Corp. 2007
+ * Author(s): Stefan Weinhuber <wein@de.ibm.com>
+ */
+
+#define KMSG_COMPONENT "dasd-eckd"
+
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <asm/ebcdic.h>
+#include "dasd_int.h"
+#include "dasd_eckd.h"
+
+#ifdef PRINTK_HEADER
+#undef PRINTK_HEADER
+#endif /* PRINTK_HEADER */
+#define PRINTK_HEADER "dasd(eckd):"
+
+
+/*
+ * 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;
+ unsigned long flags;
+ struct alias_server *server, *newserver;
+ struct alias_lcu *lcu, *newlcu;
+ struct dasd_uid uid;
+
+ private = (struct dasd_eckd_private *) device->private;
+
+ 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;
+ unsigned long flags;
+ 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;
+ /* nothing to do if already disconnected */
+ if (!lcu)
+ return;
+ 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 */
+ 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)
+ 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)
+ lcu->ruac_data.device = NULL;
+ }
+ private->lcu = NULL;
+ spin_unlock_irqrestore(&lcu->lock, flags);
+
+ spin_lock_irqsave(&aliastree.lock, flags);
+ spin_lock(&lcu->lock);
+ 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;
+ struct alias_pav_group *group;
+ struct dasd_uid uid;
+ unsigned long flags;
+
+ private = (struct dasd_eckd_private *) device->private;
+
+ /* 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) {
+ 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;
+ struct alias_pav_group *group;
+
+ private = (struct dasd_eckd_private *) device->private;
+ 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;
+
+ 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_kmalloc_request(DASD_ECKD_MAGIC, 1 /* PSF */ + 1 /* RSSD */,
+ (sizeof(struct dasd_psf_prssd_data)),
+ device);
+ 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 = (__u32)(addr_t) 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 = (__u32)(addr_t) 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);
+
+ do {
+ rc = dasd_sleep_on(cqr);
+ if (rc && suborder_not_supported(cqr))
+ return -EOPNOTSUPP;
+ } while (rc && (cqr->retries > 0));
+ if (rc) {
+ spin_lock_irqsave(&lcu->lock, flags);
+ lcu->flags |= NEED_UAC_UPDATE;
+ spin_unlock_irqrestore(&lcu->lock, flags);
+ }
+ dasd_kfree_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 = (struct dasd_eckd_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 = (struct dasd_eckd_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;
+
+ /* 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) {
+ 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);
+ }
+ spin_unlock(&lcu->lock);
+ spin_unlock_irqrestore(get_ccwdev_lock(refdev->cdev), 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);
+ schedule_delayed_work(&lcu->ruac_data.dwork, 30*HZ);
+ } else {
+ 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;
+ lcu->ruac_data.device = usedev;
+ schedule_delayed_work(&lcu->ruac_data.dwork, 0);
+ return 0;
+}
+
+int dasd_alias_add_device(struct dasd_device *device)
+{
+ struct dasd_eckd_private *private;
+ struct alias_lcu *lcu;
+ unsigned long flags;
+ int rc;
+
+ private = (struct dasd_eckd_private *) device->private;
+ lcu = private->lcu;
+ rc = 0;
+
+ /* 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, device);
+ if (rc)
+ lcu->flags |= UPDATE_PENDING;
+ }
+ if (lcu->flags & UPDATE_PENDING) {
+ list_move(&device->alias_list, &lcu->active_devices);
+ _schedule_lcu_update(lcu, device);
+ }
+ spin_unlock(&lcu->lock);
+ spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
+ return rc;
+}
+
+int dasd_alias_update_add_device(struct dasd_device *device)
+{
+ struct dasd_eckd_private *private;
+ private = (struct dasd_eckd_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;
+ struct alias_lcu *lcu;
+ unsigned long flags;
+
+ private = (struct dasd_eckd_private *) device->private;
+ lcu = private->lcu;
+ /* 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_device *alias_device;
+ struct alias_pav_group *group;
+ struct alias_lcu *lcu;
+ struct dasd_eckd_private *private, *alias_priv;
+ unsigned long flags;
+
+ private = (struct dasd_eckd_private *) base_device->private;
+ group = private->pavgroup;
+ lcu = private->lcu;
+ if (!group || !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);
+ 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 = (struct dasd_eckd_private *) alias_device->private;
+ if ((alias_priv->count < private->count) && !alias_device->stopped)
+ 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;
+ strncpy((char *) &cqr->magic, "ECKD", 4);
+ ASCEBC((char *) &cqr->magic, 4);
+ ccw = cqr->cpaddr;
+ ccw->cmd_code = DASD_ECKD_CCW_RSCK;
+ ccw->flags = 0 ;
+ ccw->count = 16;
+ ccw->cda = (__u32)(addr_t) 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;
+ 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;
+ 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;
+ 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(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;
+ int rc;
+ 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 = (struct dasd_eckd_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);
+ rc = 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);
+ }
+ spin_unlock_irqrestore(&lcu->lock, flags);
+}
+
+static void __stop_device_on_lcu(struct dasd_device *device,
+ struct dasd_device *pos)
+{
+ /* If pos == device then device is already locked! */
+ if (pos == device) {
+ dasd_device_set_stop_bits(pos, DASD_STOPPED_SU);
+ return;
+ }
+ spin_lock(get_ccwdev_lock(pos->cdev));
+ dasd_device_set_stop_bits(pos, DASD_STOPPED_SU);
+ spin_unlock(get_ccwdev_lock(pos->cdev));
+}
+
+/*
+ * This function is called in interrupt context, so the
+ * cdev lock for device is already locked!
+ */
+static void _stop_all_devices_on_lcu(struct alias_lcu *lcu,
+ struct dasd_device *device)
+{
+ struct alias_pav_group *pavgroup;
+ struct dasd_device *pos;
+
+ list_for_each_entry(pos, &lcu->active_devices, alias_list)
+ __stop_device_on_lcu(device, pos);
+ list_for_each_entry(pos, &lcu->inactive_devices, alias_list)
+ __stop_device_on_lcu(device, pos);
+ list_for_each_entry(pavgroup, &lcu->grouplist, group) {
+ list_for_each_entry(pos, &pavgroup->baselist, alias_list)
+ __stop_device_on_lcu(device, pos);
+ list_for_each_entry(pos, &pavgroup->aliaslist, alias_list)
+ __stop_device_on_lcu(device, pos);
+ }
+}
+
+static void _unstop_all_devices_on_lcu(struct alias_lcu *lcu)
+{
+ struct alias_pav_group *pavgroup;
+ struct dasd_device *device;
+ unsigned long flags;
+
+ list_for_each_entry(device, &lcu->active_devices, alias_list) {
+ spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
+ dasd_device_remove_stop_bits(device, DASD_STOPPED_SU);
+ spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
+ }
+
+ list_for_each_entry(device, &lcu->inactive_devices, alias_list) {
+ spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
+ dasd_device_remove_stop_bits(device, DASD_STOPPED_SU);
+ spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
+ }
+
+ list_for_each_entry(pavgroup, &lcu->grouplist, group) {
+ list_for_each_entry(device, &pavgroup->baselist, alias_list) {
+ spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
+ dasd_device_remove_stop_bits(device, DASD_STOPPED_SU);
+ spin_unlock_irqrestore(get_ccwdev_lock(device->cdev),
+ flags);
+ }
+ list_for_each_entry(device, &pavgroup->aliaslist, alias_list) {
+ spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
+ dasd_device_remove_stop_bits(device, DASD_STOPPED_SU);
+ spin_unlock_irqrestore(get_ccwdev_lock(device->cdev),
+ flags);
+ }
+ }
+}
+
+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;
+ spin_unlock_irqrestore(&lcu->lock, flags);
+}
+
+/*
+ * note: this will be called from int handler context (cdev locked)
+ */
+void dasd_alias_handle_summary_unit_check(struct dasd_device *device,
+ struct irb *irb)
+{
+ struct alias_lcu *lcu;
+ char reason;
+ struct dasd_eckd_private *private;
+ char *sense;
+
+ private = (struct dasd_eckd_private *) device->private;
+
+ sense = dasd_get_sense(irb);
+ if (sense) {
+ reason = sense[8];
+ DBF_DEV_EVENT(DBF_NOTICE, device, "%s %x",
+ "eckd handle summary unit check: reason", reason);
+ } else {
+ DBF_DEV_EVENT(DBF_WARNING, device, "%s",
+ "eckd handle summary unit check:"
+ " no reason code available");
+ return;
+ }
+
+ lcu = private->lcu;
+ if (!lcu) {
+ DBF_DEV_EVENT(DBF_WARNING, device, "%s",
+ "device not ready to handle summary"
+ " unit check (no lcu structure)");
+ return;
+ }
+ spin_lock(&lcu->lock);
+ _stop_all_devices_on_lcu(lcu, device);
+ /* prepare for lcu_update */
+ private->lcu->flags |= NEED_UAC_UPDATE | UPDATE_PENDING;
+ /* 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");
+ spin_unlock(&lcu->lock);
+ return;
+ }
+ 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");
+ spin_unlock(&lcu->lock);
+ return ;
+ }
+ lcu->suc_data.reason = reason;
+ lcu->suc_data.device = device;
+ spin_unlock(&lcu->lock);
+ schedule_work(&lcu->suc_data.worker);
+};
Code Review / kvmfornfv.git / blobdiff