drivers/s390/block/dasd_alias.c

   1 /*
   2  * PAV alias management for the DASD ECKD discipline
   3  *
   4  * Copyright IBM Corporation, 2007
   5  * Author(s): Stefan Weinhuber <wein@de.ibm.com>
   6  */
   7
   8 #define KMSG_COMPONENT "dasd-eckd"
   9
  10 #include <linux/list.h>
  11 #include <linux/slab.h>
  12 #include <asm/ebcdic.h>
  13 #include "dasd_int.h"
  14 #include "dasd_eckd.h"
  15
  16 #ifdef PRINTK_HEADER
  17 #undef PRINTK_HEADER
  18 #endif                          /* PRINTK_HEADER */
  19 #define PRINTK_HEADER "dasd(eckd):"
  20
  21
  22 /*
  23  * General concept of alias management:
  24  * - PAV and DASD alias management is specific to the eckd discipline.
  25  * - A device is connected to an lcu as long as the device exists.
  26  *   dasd_alias_make_device_known_to_lcu will be called wenn the
  27  *   device is checked by the eckd discipline and
  28  *   dasd_alias_disconnect_device_from_lcu will be called
  29  *   before the device is deleted.
  30  * - The dasd_alias_add_device / dasd_alias_remove_device
  31  *   functions mark the point when a device is 'ready for service'.
  32  * - A summary unit check is a rare occasion, but it is mandatory to
  33  *   support it. It requires some complex recovery actions before the
  34  *   devices can be used again (see dasd_alias_handle_summary_unit_check).
  35  * - dasd_alias_get_start_dev will find an alias device that can be used
  36  *   instead of the base device and does some (very simple) load balancing.
  37  *   This is the function that gets called for each I/O, so when improving
  38  *   something, this function should get faster or better, the rest has just
  39  *   to be correct.
  40  */
  41
  42
  43 static void summary_unit_check_handling_work(struct work_struct *);
  44 static void lcu_update_work(struct work_struct *);
  45 static int _schedule_lcu_update(struct alias_lcu *, struct dasd_device *);
  46
  47 static struct alias_root aliastree = {
  48         .serverlist = LIST_HEAD_INIT(aliastree.serverlist),
  49         .lock = __SPIN_LOCK_UNLOCKED(aliastree.lock),
  50 };
  51
  52 static struct alias_server *_find_server(struct dasd_uid *uid)
  53 {
  54         struct alias_server *pos;
  55         list_for_each_entry(pos, &aliastree.serverlist, server) {
  56                 if (!strncmp(pos->uid.vendor, uid->vendor,
  57                              sizeof(uid->vendor))
  58                     && !strncmp(pos->uid.serial, uid->serial,
  59                                 sizeof(uid->serial)))
  60                         return pos;
  61         };
  62         return NULL;
  63 }
  64
  65 static struct alias_lcu *_find_lcu(struct alias_server *server,
  66                                    struct dasd_uid *uid)
  67 {
  68         struct alias_lcu *pos;
  69         list_for_each_entry(pos, &server->lculist, lcu) {
  70                 if (pos->uid.ssid == uid->ssid)
  71                         return pos;
  72         };
  73         return NULL;
  74 }
  75
  76 static struct alias_pav_group *_find_group(struct alias_lcu *lcu,
  77                                            struct dasd_uid *uid)
  78 {
  79         struct alias_pav_group *pos;
  80         __u8 search_unit_addr;
  81
  82         /* for hyper pav there is only one group */
  83         if (lcu->pav == HYPER_PAV) {
  84                 if (list_empty(&lcu->grouplist))
  85                         return NULL;
  86                 else
  87                         return list_first_entry(&lcu->grouplist,
  88                                                 struct alias_pav_group, group);
  89         }
  90
  91         /* for base pav we have to find the group that matches the base */
  92         if (uid->type == UA_BASE_DEVICE)
  93                 search_unit_addr = uid->real_unit_addr;
  94         else
  95                 search_unit_addr = uid->base_unit_addr;
  96         list_for_each_entry(pos, &lcu->grouplist, group) {
  97                 if (pos->uid.base_unit_addr == search_unit_addr &&
  98                     !strncmp(pos->uid.vduit, uid->vduit, sizeof(uid->vduit)))
  99                         return pos;
 100         };
 101         return NULL;
 102 }
 103
 104 static struct alias_server *_allocate_server(struct dasd_uid *uid)
 105 {
 106         struct alias_server *server;
 107
 108         server = kzalloc(sizeof(*server), GFP_KERNEL);
 109         if (!server)
 110                 return ERR_PTR(-ENOMEM);
 111         memcpy(server->uid.vendor, uid->vendor, sizeof(uid->vendor));
 112         memcpy(server->uid.serial, uid->serial, sizeof(uid->serial));
 113         INIT_LIST_HEAD(&server->server);
 114         INIT_LIST_HEAD(&server->lculist);
 115         return server;
 116 }
 117
 118 static void _free_server(struct alias_server *server)
 119 {
 120         kfree(server);
 121 }
 122
 123 static struct alias_lcu *_allocate_lcu(struct dasd_uid *uid)
 124 {
 125         struct alias_lcu *lcu;
 126
 127         lcu = kzalloc(sizeof(*lcu), GFP_KERNEL);
 128         if (!lcu)
 129                 return ERR_PTR(-ENOMEM);
 130         lcu->uac = kzalloc(sizeof(*(lcu->uac)), GFP_KERNEL | GFP_DMA);
 131         if (!lcu->uac)
 132                 goto out_err1;
 133         lcu->rsu_cqr = kzalloc(sizeof(*lcu->rsu_cqr), GFP_KERNEL | GFP_DMA);
 134         if (!lcu->rsu_cqr)
 135                 goto out_err2;
 136         lcu->rsu_cqr->cpaddr = kzalloc(sizeof(struct ccw1),
 137                                        GFP_KERNEL | GFP_DMA);
 138         if (!lcu->rsu_cqr->cpaddr)
 139                 goto out_err3;
 140         lcu->rsu_cqr->data = kzalloc(16, GFP_KERNEL | GFP_DMA);
 141         if (!lcu->rsu_cqr->data)
 142                 goto out_err4;
 143
 144         memcpy(lcu->uid.vendor, uid->vendor, sizeof(uid->vendor));
 145         memcpy(lcu->uid.serial, uid->serial, sizeof(uid->serial));
 146         lcu->uid.ssid = uid->ssid;
 147         lcu->pav = NO_PAV;
 148         lcu->flags = NEED_UAC_UPDATE | UPDATE_PENDING;
 149         INIT_LIST_HEAD(&lcu->lcu);
 150         INIT_LIST_HEAD(&lcu->inactive_devices);
 151         INIT_LIST_HEAD(&lcu->active_devices);
 152         INIT_LIST_HEAD(&lcu->grouplist);
 153         INIT_WORK(&lcu->suc_data.worker, summary_unit_check_handling_work);
 154         INIT_DELAYED_WORK(&lcu->ruac_data.dwork, lcu_update_work);
 155         spin_lock_init(&lcu->lock);
 156         init_completion(&lcu->lcu_setup);
 157         return lcu;
 158
 159 out_err4:
 160         kfree(lcu->rsu_cqr->cpaddr);
 161 out_err3:
 162         kfree(lcu->rsu_cqr);
 163 out_err2:
 164         kfree(lcu->uac);
 165 out_err1:
 166         kfree(lcu);
 167         return ERR_PTR(-ENOMEM);
 168 }
 169
 170 static void _free_lcu(struct alias_lcu *lcu)
 171 {
 172         kfree(lcu->rsu_cqr->data);
 173         kfree(lcu->rsu_cqr->cpaddr);
 174         kfree(lcu->rsu_cqr);
 175         kfree(lcu->uac);
 176         kfree(lcu);
 177 }
 178
 179 /*
 180  * This is the function that will allocate all the server and lcu data,
 181  * so this function must be called first for a new device.
 182  * If the return value is 1, the lcu was already known before, if it
 183  * is 0, this is a new lcu.
 184  * Negative return code indicates that something went wrong (e.g. -ENOMEM)
 185  */
 186 int dasd_alias_make_device_known_to_lcu(struct dasd_device *device)
 187 {
 188         struct dasd_eckd_private *private;
 189         unsigned long flags;
 190         struct alias_server *server, *newserver;
 191         struct alias_lcu *lcu, *newlcu;
 192         int is_lcu_known;
 193         struct dasd_uid uid;
 194
 195         private = (struct dasd_eckd_private *) device->private;
 196
 197         device->discipline->get_uid(device, &uid);
 198         spin_lock_irqsave(&aliastree.lock, flags);
 199         is_lcu_known = 1;
 200         server = _find_server(&uid);
 201         if (!server) {
 202                 spin_unlock_irqrestore(&aliastree.lock, flags);
 203                 newserver = _allocate_server(&uid);
 204                 if (IS_ERR(newserver))
 205                         return PTR_ERR(newserver);
 206                 spin_lock_irqsave(&aliastree.lock, flags);
 207                 server = _find_server(&uid);
 208                 if (!server) {
 209                         list_add(&newserver->server, &aliastree.serverlist);
 210                         server = newserver;
 211                         is_lcu_known = 0;
 212                 } else {
 213                         /* someone was faster */
 214                         _free_server(newserver);
 215                 }
 216         }
 217
 218         lcu = _find_lcu(server, &uid);
 219         if (!lcu) {
 220                 spin_unlock_irqrestore(&aliastree.lock, flags);
 221                 newlcu = _allocate_lcu(&uid);
 222                 if (IS_ERR(newlcu))
 223                         return PTR_ERR(newlcu);
 224                 spin_lock_irqsave(&aliastree.lock, flags);
 225                 lcu = _find_lcu(server, &uid);
 226                 if (!lcu) {
 227                         list_add(&newlcu->lcu, &server->lculist);
 228                         lcu = newlcu;
 229                         is_lcu_known = 0;
 230                 } else {
 231                         /* someone was faster */
 232                         _free_lcu(newlcu);
 233                 }
 234                 is_lcu_known = 0;
 235         }
 236         spin_lock(&lcu->lock);
 237         list_add(&device->alias_list, &lcu->inactive_devices);
 238         private->lcu = lcu;
 239         spin_unlock(&lcu->lock);
 240         spin_unlock_irqrestore(&aliastree.lock, flags);
 241
 242         return is_lcu_known;
 243 }
 244
 245 /*
 246  * The first device to be registered on an LCU will have to do
 247  * some additional setup steps to configure that LCU on the
 248  * storage server. All further devices should wait with their
 249  * initialization until the first device is done.
 250  * To synchronize this work, the first device will call
 251  * dasd_alias_lcu_setup_complete when it is done, and all
 252  * other devices will wait for it with dasd_alias_wait_for_lcu_setup.
 253  */
 254 void dasd_alias_lcu_setup_complete(struct dasd_device *device)
 255 {
 256         struct dasd_eckd_private *private;
 257         unsigned long flags;
 258         struct alias_server *server;
 259         struct alias_lcu *lcu;
 260         struct dasd_uid uid;
 261
 262         private = (struct dasd_eckd_private *) device->private;
 263         device->discipline->get_uid(device, &uid);
 264         lcu = NULL;
 265         spin_lock_irqsave(&aliastree.lock, flags);
 266         server = _find_server(&uid);
 267         if (server)
 268                 lcu = _find_lcu(server, &uid);
 269         spin_unlock_irqrestore(&aliastree.lock, flags);
 270         if (!lcu) {
 271                 DBF_EVENT_DEVID(DBF_ERR, device->cdev,
 272                                 "could not find lcu for %04x %02x",
 273                                 uid.ssid, uid.real_unit_addr);
 274                 WARN_ON(1);
 275                 return;
 276         }
 277         complete_all(&lcu->lcu_setup);
 278 }
 279
 280 void dasd_alias_wait_for_lcu_setup(struct dasd_device *device)
 281 {
 282         struct dasd_eckd_private *private;
 283         unsigned long flags;
 284         struct alias_server *server;
 285         struct alias_lcu *lcu;
 286         struct dasd_uid uid;
 287
 288         private = (struct dasd_eckd_private *) device->private;
 289         device->discipline->get_uid(device, &uid);
 290         lcu = NULL;
 291         spin_lock_irqsave(&aliastree.lock, flags);
 292         server = _find_server(&uid);
 293         if (server)
 294                 lcu = _find_lcu(server, &uid);
 295         spin_unlock_irqrestore(&aliastree.lock, flags);
 296         if (!lcu) {
 297                 DBF_EVENT_DEVID(DBF_ERR, device->cdev,
 298                                 "could not find lcu for %04x %02x",
 299                                 uid.ssid, uid.real_unit_addr);
 300                 WARN_ON(1);
 301                 return;
 302         }
 303         wait_for_completion(&lcu->lcu_setup);
 304 }
 305
 306 /*
 307  * This function removes a device from the scope of alias management.
 308  * The complicated part is to make sure that it is not in use by
 309  * any of the workers. If necessary cancel the work.
 310  */
 311 void dasd_alias_disconnect_device_from_lcu(struct dasd_device *device)
 312 {
 313         struct dasd_eckd_private *private;
 314         unsigned long flags;
 315         struct alias_lcu *lcu;
 316         struct alias_server *server;
 317         int was_pending;
 318         struct dasd_uid uid;
 319
 320         private = (struct dasd_eckd_private *) device->private;
 321         lcu = private->lcu;
 322         device->discipline->get_uid(device, &uid);
 323         spin_lock_irqsave(&lcu->lock, flags);
 324         list_del_init(&device->alias_list);
 325         /* make sure that the workers don't use this device */
 326         if (device == lcu->suc_data.device) {
 327                 spin_unlock_irqrestore(&lcu->lock, flags);
 328                 cancel_work_sync(&lcu->suc_data.worker);
 329                 spin_lock_irqsave(&lcu->lock, flags);
 330                 if (device == lcu->suc_data.device)
 331                         lcu->suc_data.device = NULL;
 332         }
 333         was_pending = 0;
 334         if (device == lcu->ruac_data.device) {
 335                 spin_unlock_irqrestore(&lcu->lock, flags);
 336                 was_pending = 1;
 337                 cancel_delayed_work_sync(&lcu->ruac_data.dwork);
 338                 spin_lock_irqsave(&lcu->lock, flags);
 339                 if (device == lcu->ruac_data.device)
 340                         lcu->ruac_data.device = NULL;
 341         }
 342         private->lcu = NULL;
 343         spin_unlock_irqrestore(&lcu->lock, flags);
 344
 345         spin_lock_irqsave(&aliastree.lock, flags);
 346         spin_lock(&lcu->lock);
 347         if (list_empty(&lcu->grouplist) &&
 348             list_empty(&lcu->active_devices) &&
 349             list_empty(&lcu->inactive_devices)) {
 350                 list_del(&lcu->lcu);
 351                 spin_unlock(&lcu->lock);
 352                 _free_lcu(lcu);
 353                 lcu = NULL;
 354         } else {
 355                 if (was_pending)
 356                         _schedule_lcu_update(lcu, NULL);
 357                 spin_unlock(&lcu->lock);
 358         }
 359         server = _find_server(&uid);
 360         if (server && list_empty(&server->lculist)) {
 361                 list_del(&server->server);
 362                 _free_server(server);
 363         }
 364         spin_unlock_irqrestore(&aliastree.lock, flags);
 365 }
 366
 367 /*
 368  * This function assumes that the unit address configuration stored
 369  * in the lcu is up to date and will update the device uid before
 370  * adding it to a pav group.
 371  */
 372
 373 static int _add_device_to_lcu(struct alias_lcu *lcu,
 374                               struct dasd_device *device,
 375                               struct dasd_device *pos)
 376 {
 377
 378         struct dasd_eckd_private *private;
 379         struct alias_pav_group *group;
 380         struct dasd_uid uid;
 381         unsigned long flags;
 382
 383         private = (struct dasd_eckd_private *) device->private;
 384
 385         /* only lock if not already locked */
 386         if (device != pos)
 387                 spin_lock_irqsave_nested(get_ccwdev_lock(device->cdev), flags,
 388                                          CDEV_NESTED_SECOND);
 389         private->uid.type = lcu->uac->unit[private->uid.real_unit_addr].ua_type;
 390         private->uid.base_unit_addr =
 391                 lcu->uac->unit[private->uid.real_unit_addr].base_ua;
 392         uid = private->uid;
 393
 394         if (device != pos)
 395                 spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
 396
 397         /* if we have no PAV anyway, we don't need to bother with PAV groups */
 398         if (lcu->pav == NO_PAV) {
 399                 list_move(&device->alias_list, &lcu->active_devices);
 400                 return 0;
 401         }
 402
 403         group = _find_group(lcu, &uid);
 404         if (!group) {
 405                 group = kzalloc(sizeof(*group), GFP_ATOMIC);
 406                 if (!group)
 407                         return -ENOMEM;
 408                 memcpy(group->uid.vendor, uid.vendor, sizeof(uid.vendor));
 409                 memcpy(group->uid.serial, uid.serial, sizeof(uid.serial));
 410                 group->uid.ssid = uid.ssid;
 411                 if (uid.type == UA_BASE_DEVICE)
 412                         group->uid.base_unit_addr = uid.real_unit_addr;
 413                 else
 414                         group->uid.base_unit_addr = uid.base_unit_addr;
 415                 memcpy(group->uid.vduit, uid.vduit, sizeof(uid.vduit));
 416                 INIT_LIST_HEAD(&group->group);
 417                 INIT_LIST_HEAD(&group->baselist);
 418                 INIT_LIST_HEAD(&group->aliaslist);
 419                 list_add(&group->group, &lcu->grouplist);
 420         }
 421         if (uid.type == UA_BASE_DEVICE)
 422                 list_move(&device->alias_list, &group->baselist);
 423         else
 424                 list_move(&device->alias_list, &group->aliaslist);
 425         private->pavgroup = group;
 426         return 0;
 427 };
 428
 429 static void _remove_device_from_lcu(struct alias_lcu *lcu,
 430                                     struct dasd_device *device)
 431 {
 432         struct dasd_eckd_private *private;
 433         struct alias_pav_group *group;
 434
 435         private = (struct dasd_eckd_private *) device->private;
 436         list_move(&device->alias_list, &lcu->inactive_devices);
 437         group = private->pavgroup;
 438         if (!group)
 439                 return;
 440         private->pavgroup = NULL;
 441         if (list_empty(&group->baselist) && list_empty(&group->aliaslist)) {
 442                 list_del(&group->group);
 443                 kfree(group);
 444                 return;
 445         }
 446         if (group->next == device)
 447                 group->next = NULL;
 448 };
 449
 450 static int read_unit_address_configuration(struct dasd_device *device,
 451                                            struct alias_lcu *lcu)
 452 {
 453         struct dasd_psf_prssd_data *prssdp;
 454         struct dasd_ccw_req *cqr;
 455         struct ccw1 *ccw;
 456         int rc;
 457         unsigned long flags;
 458
 459         cqr = dasd_kmalloc_request(DASD_ECKD_MAGIC, 1 /* PSF */ + 1 /* RSSD */,
 460                                    (sizeof(struct dasd_psf_prssd_data)),
 461                                    device);
 462         if (IS_ERR(cqr))
 463                 return PTR_ERR(cqr);
 464         cqr->startdev = device;
 465         cqr->memdev = device;
 466         clear_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags);
 467         cqr->retries = 10;
 468         cqr->expires = 20 * HZ;
 469
 470         /* Prepare for Read Subsystem Data */
 471         prssdp = (struct dasd_psf_prssd_data *) cqr->data;
 472         memset(prssdp, 0, sizeof(struct dasd_psf_prssd_data));
 473         prssdp->order = PSF_ORDER_PRSSD;
 474         prssdp->suborder = 0x0e;        /* Read unit address configuration */
 475         /* all other bytes of prssdp must be zero */
 476
 477         ccw = cqr->cpaddr;
 478         ccw->cmd_code = DASD_ECKD_CCW_PSF;
 479         ccw->count = sizeof(struct dasd_psf_prssd_data);
 480         ccw->flags |= CCW_FLAG_CC;
 481         ccw->cda = (__u32)(addr_t) prssdp;
 482
 483         /* Read Subsystem Data - feature codes */
 484         memset(lcu->uac, 0, sizeof(*(lcu->uac)));
 485
 486         ccw++;
 487         ccw->cmd_code = DASD_ECKD_CCW_RSSD;
 488         ccw->count = sizeof(*(lcu->uac));
 489         ccw->cda = (__u32)(addr_t) lcu->uac;
 490
 491         cqr->buildclk = get_clock();
 492         cqr->status = DASD_CQR_FILLED;
 493
 494         /* need to unset flag here to detect race with summary unit check */
 495         spin_lock_irqsave(&lcu->lock, flags);
 496         lcu->flags &= ~NEED_UAC_UPDATE;
 497         spin_unlock_irqrestore(&lcu->lock, flags);
 498
 499         do {
 500                 rc = dasd_sleep_on(cqr);
 501         } while (rc && (cqr->retries > 0));
 502         if (rc) {
 503                 spin_lock_irqsave(&lcu->lock, flags);
 504                 lcu->flags |= NEED_UAC_UPDATE;
 505                 spin_unlock_irqrestore(&lcu->lock, flags);
 506         }
 507         dasd_kfree_request(cqr, cqr->memdev);
 508         return rc;
 509 }
 510
 511 static int _lcu_update(struct dasd_device *refdev, struct alias_lcu *lcu)
 512 {
 513         unsigned long flags;
 514         struct alias_pav_group *pavgroup, *tempgroup;
 515         struct dasd_device *device, *tempdev;
 516         int i, rc;
 517         struct dasd_eckd_private *private;
 518
 519         spin_lock_irqsave(&lcu->lock, flags);
 520         list_for_each_entry_safe(pavgroup, tempgroup, &lcu->grouplist, group) {
 521                 list_for_each_entry_safe(device, tempdev, &pavgroup->baselist,
 522                                          alias_list) {
 523                         list_move(&device->alias_list, &lcu->active_devices);
 524                         private = (struct dasd_eckd_private *) device->private;
 525                         private->pavgroup = NULL;
 526                 }
 527                 list_for_each_entry_safe(device, tempdev, &pavgroup->aliaslist,
 528                                          alias_list) {
 529                         list_move(&device->alias_list, &lcu->active_devices);
 530                         private = (struct dasd_eckd_private *) device->private;
 531                         private->pavgroup = NULL;
 532                 }
 533                 list_del(&pavgroup->group);
 534                 kfree(pavgroup);
 535         }
 536         spin_unlock_irqrestore(&lcu->lock, flags);
 537
 538         rc = read_unit_address_configuration(refdev, lcu);
 539         if (rc)
 540                 return rc;
 541
 542         /* need to take cdev lock before lcu lock */
 543         spin_lock_irqsave_nested(get_ccwdev_lock(refdev->cdev), flags,
 544                                  CDEV_NESTED_FIRST);
 545         spin_lock(&lcu->lock);
 546         lcu->pav = NO_PAV;
 547         for (i = 0; i < MAX_DEVICES_PER_LCU; ++i) {
 548                 switch (lcu->uac->unit[i].ua_type) {
 549                 case UA_BASE_PAV_ALIAS:
 550                         lcu->pav = BASE_PAV;
 551                         break;
 552                 case UA_HYPER_PAV_ALIAS:
 553                         lcu->pav = HYPER_PAV;
 554                         break;
 555                 }
 556                 if (lcu->pav != NO_PAV)
 557                         break;
 558         }
 559
 560         list_for_each_entry_safe(device, tempdev, &lcu->active_devices,
 561                                  alias_list) {
 562                 _add_device_to_lcu(lcu, device, refdev);
 563         }
 564         spin_unlock(&lcu->lock);
 565         spin_unlock_irqrestore(get_ccwdev_lock(refdev->cdev), flags);
 566         return 0;
 567 }
 568
 569 static void lcu_update_work(struct work_struct *work)
 570 {
 571         struct alias_lcu *lcu;
 572         struct read_uac_work_data *ruac_data;
 573         struct dasd_device *device;
 574         unsigned long flags;
 575         int rc;
 576
 577         ruac_data = container_of(work, struct read_uac_work_data, dwork.work);
 578         lcu = container_of(ruac_data, struct alias_lcu, ruac_data);
 579         device = ruac_data->device;
 580         rc = _lcu_update(device, lcu);
 581         /*
 582          * Need to check flags again, as there could have been another
 583          * prepare_update or a new device a new device while we were still
 584          * processing the data
 585          */
 586         spin_lock_irqsave(&lcu->lock, flags);
 587         if (rc || (lcu->flags & NEED_UAC_UPDATE)) {
 588                 DBF_DEV_EVENT(DBF_WARNING, device, "could not update"
 589                             " alias data in lcu (rc = %d), retry later", rc);
 590                 schedule_delayed_work(&lcu->ruac_data.dwork, 30*HZ);
 591         } else {
 592                 lcu->ruac_data.device = NULL;
 593                 lcu->flags &= ~UPDATE_PENDING;
 594         }
 595         spin_unlock_irqrestore(&lcu->lock, flags);
 596 }
 597
 598 static int _schedule_lcu_update(struct alias_lcu *lcu,
 599                                 struct dasd_device *device)
 600 {
 601         struct dasd_device *usedev = NULL;
 602         struct alias_pav_group *group;
 603
 604         lcu->flags |= NEED_UAC_UPDATE;
 605         if (lcu->ruac_data.device) {
 606                 /* already scheduled or running */
 607                 return 0;
 608         }
 609         if (device && !list_empty(&device->alias_list))
 610                 usedev = device;
 611
 612         if (!usedev && !list_empty(&lcu->grouplist)) {
 613                 group = list_first_entry(&lcu->grouplist,
 614                                          struct alias_pav_group, group);
 615                 if (!list_empty(&group->baselist))
 616                         usedev = list_first_entry(&group->baselist,
 617                                                   struct dasd_device,
 618                                                   alias_list);
 619                 else if (!list_empty(&group->aliaslist))
 620                         usedev = list_first_entry(&group->aliaslist,
 621                                                   struct dasd_device,
 622                                                   alias_list);
 623         }
 624         if (!usedev && !list_empty(&lcu->active_devices)) {
 625                 usedev = list_first_entry(&lcu->active_devices,
 626                                           struct dasd_device, alias_list);
 627         }
 628         /*
 629          * if we haven't found a proper device yet, give up for now, the next
 630          * device that will be set active will trigger an lcu update
 631          */
 632         if (!usedev)
 633                 return -EINVAL;
 634         lcu->ruac_data.device = usedev;
 635         schedule_delayed_work(&lcu->ruac_data.dwork, 0);
 636         return 0;
 637 }
 638
 639 int dasd_alias_add_device(struct dasd_device *device)
 640 {
 641         struct dasd_eckd_private *private;
 642         struct alias_lcu *lcu;
 643         unsigned long flags;
 644         int rc;
 645
 646         private = (struct dasd_eckd_private *) device->private;
 647         lcu = private->lcu;
 648         rc = 0;
 649
 650         /* need to take cdev lock before lcu lock */
 651         spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
 652         spin_lock(&lcu->lock);
 653         if (!(lcu->flags & UPDATE_PENDING)) {
 654                 rc = _add_device_to_lcu(lcu, device, device);
 655                 if (rc)
 656                         lcu->flags |= UPDATE_PENDING;
 657         }
 658         if (lcu->flags & UPDATE_PENDING) {
 659                 list_move(&device->alias_list, &lcu->active_devices);
 660                 _schedule_lcu_update(lcu, device);
 661         }
 662         spin_unlock(&lcu->lock);
 663         spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
 664         return rc;
 665 }
 666
 667 int dasd_alias_update_add_device(struct dasd_device *device)
 668 {
 669         struct dasd_eckd_private *private;
 670         private = (struct dasd_eckd_private *) device->private;
 671         private->lcu->flags |= UPDATE_PENDING;
 672         return dasd_alias_add_device(device);
 673 }
 674
 675 int dasd_alias_remove_device(struct dasd_device *device)
 676 {
 677         struct dasd_eckd_private *private;
 678         struct alias_lcu *lcu;
 679         unsigned long flags;
 680
 681         private = (struct dasd_eckd_private *) device->private;
 682         lcu = private->lcu;
 683         spin_lock_irqsave(&lcu->lock, flags);
 684         _remove_device_from_lcu(lcu, device);
 685         spin_unlock_irqrestore(&lcu->lock, flags);
 686         return 0;
 687 }
 688
 689 struct dasd_device *dasd_alias_get_start_dev(struct dasd_device *base_device)
 690 {
 691
 692         struct dasd_device *alias_device;
 693         struct alias_pav_group *group;
 694         struct alias_lcu *lcu;
 695         struct dasd_eckd_private *private, *alias_priv;
 696         unsigned long flags;
 697
 698         private = (struct dasd_eckd_private *) base_device->private;
 699         group = private->pavgroup;
 700         lcu = private->lcu;
 701         if (!group || !lcu)
 702                 return NULL;
 703         if (lcu->pav == NO_PAV ||
 704             lcu->flags & (NEED_UAC_UPDATE | UPDATE_PENDING))
 705                 return NULL;
 706
 707         spin_lock_irqsave(&lcu->lock, flags);
 708         alias_device = group->next;
 709         if (!alias_device) {
 710                 if (list_empty(&group->aliaslist)) {
 711                         spin_unlock_irqrestore(&lcu->lock, flags);
 712                         return NULL;
 713                 } else {
 714                         alias_device = list_first_entry(&group->aliaslist,
 715                                                         struct dasd_device,
 716                                                         alias_list);
 717                 }
 718         }
 719         if (list_is_last(&alias_device->alias_list, &group->aliaslist))
 720                 group->next = list_first_entry(&group->aliaslist,
 721                                                struct dasd_device, alias_list);
 722         else
 723                 group->next = list_first_entry(&alias_device->alias_list,
 724                                                struct dasd_device, alias_list);
 725         spin_unlock_irqrestore(&lcu->lock, flags);
 726         alias_priv = (struct dasd_eckd_private *) alias_device->private;
 727         if ((alias_priv->count < private->count) && !alias_device->stopped)
 728                 return alias_device;
 729         else
 730                 return NULL;
 731 }
 732
 733 /*
 734  * Summary unit check handling depends on the way alias devices
 735  * are handled so it is done here rather then in dasd_eckd.c
 736  */
 737 static int reset_summary_unit_check(struct alias_lcu *lcu,
 738                                     struct dasd_device *device,
 739                                     char reason)
 740 {
 741         struct dasd_ccw_req *cqr;
 742         int rc = 0;
 743         struct ccw1 *ccw;
 744
 745         cqr = lcu->rsu_cqr;
 746         strncpy((char *) &cqr->magic, "ECKD", 4);
 747         ASCEBC((char *) &cqr->magic, 4);
 748         ccw = cqr->cpaddr;
 749         ccw->cmd_code = DASD_ECKD_CCW_RSCK;
 750         ccw->flags = 0 ;
 751         ccw->count = 16;
 752         ccw->cda = (__u32)(addr_t) cqr->data;
 753         ((char *)cqr->data)[0] = reason;
 754
 755         clear_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags);
 756         cqr->retries = 255;     /* set retry counter to enable basic ERP */
 757         cqr->startdev = device;
 758         cqr->memdev = device;
 759         cqr->block = NULL;
 760         cqr->expires = 5 * HZ;
 761         cqr->buildclk = get_clock();
 762         cqr->status = DASD_CQR_FILLED;
 763
 764         rc = dasd_sleep_on_immediatly(cqr);
 765         return rc;
 766 }
 767
 768 static void _restart_all_base_devices_on_lcu(struct alias_lcu *lcu)
 769 {
 770         struct alias_pav_group *pavgroup;
 771         struct dasd_device *device;
 772         struct dasd_eckd_private *private;
 773         unsigned long flags;
 774
 775         /* active and inactive list can contain alias as well as base devices */
 776         list_for_each_entry(device, &lcu->active_devices, alias_list) {
 777                 private = (struct dasd_eckd_private *) device->private;
 778                 spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
 779                 if (private->uid.type != UA_BASE_DEVICE) {
 780                         spin_unlock_irqrestore(get_ccwdev_lock(device->cdev),
 781                                                flags);
 782                         continue;
 783                 }
 784                 spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
 785                 dasd_schedule_block_bh(device->block);
 786                 dasd_schedule_device_bh(device);
 787         }
 788         list_for_each_entry(device, &lcu->inactive_devices, alias_list) {
 789                 private = (struct dasd_eckd_private *) device->private;
 790                 spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
 791                 if (private->uid.type != UA_BASE_DEVICE) {
 792                         spin_unlock_irqrestore(get_ccwdev_lock(device->cdev),
 793                                                flags);
 794                         continue;
 795                 }
 796                 spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
 797                 dasd_schedule_block_bh(device->block);
 798                 dasd_schedule_device_bh(device);
 799         }
 800         list_for_each_entry(pavgroup, &lcu->grouplist, group) {
 801                 list_for_each_entry(device, &pavgroup->baselist, alias_list) {
 802                         dasd_schedule_block_bh(device->block);
 803                         dasd_schedule_device_bh(device);
 804                 }
 805         }
 806 }
 807
 808 static void flush_all_alias_devices_on_lcu(struct alias_lcu *lcu)
 809 {
 810         struct alias_pav_group *pavgroup;
 811         struct dasd_device *device, *temp;
 812         struct dasd_eckd_private *private;
 813         int rc;
 814         unsigned long flags;
 815         LIST_HEAD(active);
 816
 817         /*
 818          * Problem here ist that dasd_flush_device_queue may wait
 819          * for termination of a request to complete. We can't keep
 820          * the lcu lock during that time, so we must assume that
 821          * the lists may have changed.
 822          * Idea: first gather all active alias devices in a separate list,
 823          * then flush the first element of this list unlocked, and afterwards
 824          * check if it is still on the list before moving it to the
 825          * active_devices list.
 826          */
 827
 828         spin_lock_irqsave(&lcu->lock, flags);
 829         list_for_each_entry_safe(device, temp, &lcu->active_devices,
 830                                  alias_list) {
 831                 private = (struct dasd_eckd_private *) device->private;
 832                 if (private->uid.type == UA_BASE_DEVICE)
 833                         continue;
 834                 list_move(&device->alias_list, &active);
 835         }
 836
 837         list_for_each_entry(pavgroup, &lcu->grouplist, group) {
 838                 list_splice_init(&pavgroup->aliaslist, &active);
 839         }
 840         while (!list_empty(&active)) {
 841                 device = list_first_entry(&active, struct dasd_device,
 842                                           alias_list);
 843                 spin_unlock_irqrestore(&lcu->lock, flags);
 844                 rc = dasd_flush_device_queue(device);
 845                 spin_lock_irqsave(&lcu->lock, flags);
 846                 /*
 847                  * only move device around if it wasn't moved away while we
 848                  * were waiting for the flush
 849                  */
 850                 if (device == list_first_entry(&active,
 851                                                struct dasd_device, alias_list))
 852                         list_move(&device->alias_list, &lcu->active_devices);
 853         }
 854         spin_unlock_irqrestore(&lcu->lock, flags);
 855 }
 856
 857 static void __stop_device_on_lcu(struct dasd_device *device,
 858                                  struct dasd_device *pos)
 859 {
 860         /* If pos == device then device is already locked! */
 861         if (pos == device) {
 862                 dasd_device_set_stop_bits(pos, DASD_STOPPED_SU);
 863                 return;
 864         }
 865         spin_lock(get_ccwdev_lock(pos->cdev));
 866         dasd_device_set_stop_bits(pos, DASD_STOPPED_SU);
 867         spin_unlock(get_ccwdev_lock(pos->cdev));
 868 }
 869
 870 /*
 871  * This function is called in interrupt context, so the
 872  * cdev lock for device is already locked!
 873  */
 874 static void _stop_all_devices_on_lcu(struct alias_lcu *lcu,
 875                                      struct dasd_device *device)
 876 {
 877         struct alias_pav_group *pavgroup;
 878         struct dasd_device *pos;
 879
 880         list_for_each_entry(pos, &lcu->active_devices, alias_list)
 881                 __stop_device_on_lcu(device, pos);
 882         list_for_each_entry(pos, &lcu->inactive_devices, alias_list)
 883                 __stop_device_on_lcu(device, pos);
 884         list_for_each_entry(pavgroup, &lcu->grouplist, group) {
 885                 list_for_each_entry(pos, &pavgroup->baselist, alias_list)
 886                         __stop_device_on_lcu(device, pos);
 887                 list_for_each_entry(pos, &pavgroup->aliaslist, alias_list)
 888                         __stop_device_on_lcu(device, pos);
 889         }
 890 }
 891
 892 static void _unstop_all_devices_on_lcu(struct alias_lcu *lcu)
 893 {
 894         struct alias_pav_group *pavgroup;
 895         struct dasd_device *device;
 896         unsigned long flags;
 897
 898         list_for_each_entry(device, &lcu->active_devices, alias_list) {
 899                 spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
 900                 dasd_device_remove_stop_bits(device, DASD_STOPPED_SU);
 901                 spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
 902         }
 903
 904         list_for_each_entry(device, &lcu->inactive_devices, alias_list) {
 905                 spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
 906                 dasd_device_remove_stop_bits(device, DASD_STOPPED_SU);
 907                 spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
 908         }
 909
 910         list_for_each_entry(pavgroup, &lcu->grouplist, group) {
 911                 list_for_each_entry(device, &pavgroup->baselist, alias_list) {
 912                         spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
 913                         dasd_device_remove_stop_bits(device, DASD_STOPPED_SU);
 914                         spin_unlock_irqrestore(get_ccwdev_lock(device->cdev),
 915                                                flags);
 916                 }
 917                 list_for_each_entry(device, &pavgroup->aliaslist, alias_list) {
 918                         spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
 919                         dasd_device_remove_stop_bits(device, DASD_STOPPED_SU);
 920                         spin_unlock_irqrestore(get_ccwdev_lock(device->cdev),
 921                                                flags);
 922                 }
 923         }
 924 }
 925
 926 static void summary_unit_check_handling_work(struct work_struct *work)
 927 {
 928         struct alias_lcu *lcu;
 929         struct summary_unit_check_work_data *suc_data;
 930         unsigned long flags;
 931         struct dasd_device *device;
 932
 933         suc_data = container_of(work, struct summary_unit_check_work_data,
 934                                 worker);
 935         lcu = container_of(suc_data, struct alias_lcu, suc_data);
 936         device = suc_data->device;
 937
 938         /* 1. flush alias devices */
 939         flush_all_alias_devices_on_lcu(lcu);
 940
 941         /* 2. reset summary unit check */
 942         spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
 943         dasd_device_remove_stop_bits(device,
 944                                      (DASD_STOPPED_SU | DASD_STOPPED_PENDING));
 945         spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
 946         reset_summary_unit_check(lcu, device, suc_data->reason);
 947
 948         spin_lock_irqsave(&lcu->lock, flags);
 949         _unstop_all_devices_on_lcu(lcu);
 950         _restart_all_base_devices_on_lcu(lcu);
 951         /* 3. read new alias configuration */
 952         _schedule_lcu_update(lcu, device);
 953         lcu->suc_data.device = NULL;
 954         spin_unlock_irqrestore(&lcu->lock, flags);
 955 }
 956
 957 /*
 958  * note: this will be called from int handler context (cdev locked)
 959  */
 960 void dasd_alias_handle_summary_unit_check(struct dasd_device *device,
 961                                           struct irb *irb)
 962 {
 963         struct alias_lcu *lcu;
 964         char reason;
 965         struct dasd_eckd_private *private;
 966         char *sense;
 967
 968         private = (struct dasd_eckd_private *) device->private;
 969
 970         sense = dasd_get_sense(irb);
 971         if (sense) {
 972                 reason = sense[8];
 973                 DBF_DEV_EVENT(DBF_NOTICE, device, "%s %x",
 974                             "eckd handle summary unit check: reason", reason);
 975         } else {
 976                 DBF_DEV_EVENT(DBF_WARNING, device, "%s",
 977                             "eckd handle summary unit check:"
 978                             " no reason code available");
 979                 return;
 980         }
 981
 982         lcu = private->lcu;
 983         if (!lcu) {
 984                 DBF_DEV_EVENT(DBF_WARNING, device, "%s",
 985                             "device not ready to handle summary"
 986                             " unit check (no lcu structure)");
 987                 return;
 988         }
 989         spin_lock(&lcu->lock);
 990         _stop_all_devices_on_lcu(lcu, device);
 991         /* prepare for lcu_update */
 992         private->lcu->flags |= NEED_UAC_UPDATE | UPDATE_PENDING;
 993         /* If this device is about to be removed just return and wait for
 994          * the next interrupt on a different device
 995          */
 996         if (list_empty(&device->alias_list)) {
 997                 DBF_DEV_EVENT(DBF_WARNING, device, "%s",
 998                             "device is in offline processing,"
 999                             " don't do summary unit check handling");
1000                 spin_unlock(&lcu->lock);
1001                 return;
1002         }
1003         if (lcu->suc_data.device) {
1004                 /* already scheduled or running */
1005                 DBF_DEV_EVENT(DBF_WARNING, device, "%s",
1006                             "previous instance of summary unit check worker"
1007                             " still pending");
1008                 spin_unlock(&lcu->lock);
1009                 return ;
1010         }
1011         lcu->suc_data.reason = reason;
1012         lcu->suc_data.device = device;
1013         spin_unlock(&lcu->lock);
1014         schedule_work(&lcu->suc_data.worker);
1015 };