drivers/s390/block/dasd_alias.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * PAV alias management for the DASD ECKD discipline
   4  *
   5  * Copyright IBM Corp. 2007
   6  * Author(s): Stefan Weinhuber <wein@de.ibm.com>
   7  */
   8
   9 #include <linux/list.h>
  10 #include <linux/slab.h>
  11 #include <asm/ebcdic.h>
  12 #include "dasd_int.h"
  13 #include "dasd_eckd.h"
  14
  15 /*
  16  * General concept of alias management:
  17  * - PAV and DASD alias management is specific to the eckd discipline.
  18  * - A device is connected to an lcu as long as the device exists.
  19  *   dasd_alias_make_device_known_to_lcu will be called wenn the
  20  *   device is checked by the eckd discipline and
  21  *   dasd_alias_disconnect_device_from_lcu will be called
  22  *   before the device is deleted.
  23  * - The dasd_alias_add_device / dasd_alias_remove_device
  24  *   functions mark the point when a device is 'ready for service'.
  25  * - A summary unit check is a rare occasion, but it is mandatory to
  26  *   support it. It requires some complex recovery actions before the
  27  *   devices can be used again (see dasd_alias_handle_summary_unit_check).
  28  * - dasd_alias_get_start_dev will find an alias device that can be used
  29  *   instead of the base device and does some (very simple) load balancing.
  30  *   This is the function that gets called for each I/O, so when improving
  31  *   something, this function should get faster or better, the rest has just
  32  *   to be correct.
  33  */
  34
  35
  36 static void summary_unit_check_handling_work(struct work_struct *);
  37 static void lcu_update_work(struct work_struct *);
  38 static int _schedule_lcu_update(struct alias_lcu *, struct dasd_device *);
  39
  40 static struct alias_root aliastree = {
  41         .serverlist = LIST_HEAD_INIT(aliastree.serverlist),
  42         .lock = __SPIN_LOCK_UNLOCKED(aliastree.lock),
  43 };
  44
  45 static struct alias_server *_find_server(struct dasd_uid *uid)
  46 {
  47         struct alias_server *pos;
  48         list_for_each_entry(pos, &aliastree.serverlist, server) {
  49                 if (!strncmp(pos->uid.vendor, uid->vendor,
  50                              sizeof(uid->vendor))
  51                     && !strncmp(pos->uid.serial, uid->serial,
  52                                 sizeof(uid->serial)))
  53                         return pos;
  54         }
  55         return NULL;
  56 }
  57
  58 static struct alias_lcu *_find_lcu(struct alias_server *server,
  59                                    struct dasd_uid *uid)
  60 {
  61         struct alias_lcu *pos;
  62         list_for_each_entry(pos, &server->lculist, lcu) {
  63                 if (pos->uid.ssid == uid->ssid)
  64                         return pos;
  65         }
  66         return NULL;
  67 }
  68
  69 static struct alias_pav_group *_find_group(struct alias_lcu *lcu,
  70                                            struct dasd_uid *uid)
  71 {
  72         struct alias_pav_group *pos;
  73         __u8 search_unit_addr;
  74
  75         /* for hyper pav there is only one group */
  76         if (lcu->pav == HYPER_PAV) {
  77                 if (list_empty(&lcu->grouplist))
  78                         return NULL;
  79                 else
  80                         return list_first_entry(&lcu->grouplist,
  81                                                 struct alias_pav_group, group);
  82         }
  83
  84         /* for base pav we have to find the group that matches the base */
  85         if (uid->type == UA_BASE_DEVICE)
  86                 search_unit_addr = uid->real_unit_addr;
  87         else
  88                 search_unit_addr = uid->base_unit_addr;
  89         list_for_each_entry(pos, &lcu->grouplist, group) {
  90                 if (pos->uid.base_unit_addr == search_unit_addr &&
  91                     !strncmp(pos->uid.vduit, uid->vduit, sizeof(uid->vduit)))
  92                         return pos;
  93         }
  94         return NULL;
  95 }
  96
  97 static struct alias_server *_allocate_server(struct dasd_uid *uid)
  98 {
  99         struct alias_server *server;
 100
 101         server = kzalloc(sizeof(*server), GFP_KERNEL);
 102         if (!server)
 103                 return ERR_PTR(-ENOMEM);
 104         memcpy(server->uid.vendor, uid->vendor, sizeof(uid->vendor));
 105         memcpy(server->uid.serial, uid->serial, sizeof(uid->serial));
 106         INIT_LIST_HEAD(&server->server);
 107         INIT_LIST_HEAD(&server->lculist);
 108         return server;
 109 }
 110
 111 static void _free_server(struct alias_server *server)
 112 {
 113         kfree(server);
 114 }
 115
 116 static struct alias_lcu *_allocate_lcu(struct dasd_uid *uid)
 117 {
 118         struct alias_lcu *lcu;
 119
 120         lcu = kzalloc(sizeof(*lcu), GFP_KERNEL);
 121         if (!lcu)
 122                 return ERR_PTR(-ENOMEM);
 123         lcu->uac = kzalloc(sizeof(*(lcu->uac)), GFP_KERNEL | GFP_DMA);
 124         if (!lcu->uac)
 125                 goto out_err1;
 126         lcu->rsu_cqr = kzalloc(sizeof(*lcu->rsu_cqr), GFP_KERNEL | GFP_DMA);
 127         if (!lcu->rsu_cqr)
 128                 goto out_err2;
 129         lcu->rsu_cqr->cpaddr = kzalloc(sizeof(struct ccw1),
 130                                        GFP_KERNEL | GFP_DMA);
 131         if (!lcu->rsu_cqr->cpaddr)
 132                 goto out_err3;
 133         lcu->rsu_cqr->data = kzalloc(16, GFP_KERNEL | GFP_DMA);
 134         if (!lcu->rsu_cqr->data)
 135                 goto out_err4;
 136
 137         memcpy(lcu->uid.vendor, uid->vendor, sizeof(uid->vendor));
 138         memcpy(lcu->uid.serial, uid->serial, sizeof(uid->serial));
 139         lcu->uid.ssid = uid->ssid;
 140         lcu->pav = NO_PAV;
 141         lcu->flags = NEED_UAC_UPDATE | UPDATE_PENDING;
 142         INIT_LIST_HEAD(&lcu->lcu);
 143         INIT_LIST_HEAD(&lcu->inactive_devices);
 144         INIT_LIST_HEAD(&lcu->active_devices);
 145         INIT_LIST_HEAD(&lcu->grouplist);
 146         INIT_WORK(&lcu->suc_data.worker, summary_unit_check_handling_work);
 147         INIT_DELAYED_WORK(&lcu->ruac_data.dwork, lcu_update_work);
 148         spin_lock_init(&lcu->lock);
 149         init_completion(&lcu->lcu_setup);
 150         return lcu;
 151
 152 out_err4:
 153         kfree(lcu->rsu_cqr->cpaddr);
 154 out_err3:
 155         kfree(lcu->rsu_cqr);
 156 out_err2:
 157         kfree(lcu->uac);
 158 out_err1:
 159         kfree(lcu);
 160         return ERR_PTR(-ENOMEM);
 161 }
 162
 163 static void _free_lcu(struct alias_lcu *lcu)
 164 {
 165         kfree(lcu->rsu_cqr->data);
 166         kfree(lcu->rsu_cqr->cpaddr);
 167         kfree(lcu->rsu_cqr);
 168         kfree(lcu->uac);
 169         kfree(lcu);
 170 }
 171
 172 /*
 173  * This is the function that will allocate all the server and lcu data,
 174  * so this function must be called first for a new device.
 175  * If the return value is 1, the lcu was already known before, if it
 176  * is 0, this is a new lcu.
 177  * Negative return code indicates that something went wrong (e.g. -ENOMEM)
 178  */
 179 int dasd_alias_make_device_known_to_lcu(struct dasd_device *device)
 180 {
 181         struct dasd_eckd_private *private = device->private;
 182         unsigned long flags;
 183         struct alias_server *server, *newserver;
 184         struct alias_lcu *lcu, *newlcu;
 185         struct dasd_uid uid;
 186
 187         device->discipline->get_uid(device, &uid);
 188         spin_lock_irqsave(&aliastree.lock, flags);
 189         server = _find_server(&uid);
 190         if (!server) {
 191                 spin_unlock_irqrestore(&aliastree.lock, flags);
 192                 newserver = _allocate_server(&uid);
 193                 if (IS_ERR(newserver))
 194                         return PTR_ERR(newserver);
 195                 spin_lock_irqsave(&aliastree.lock, flags);
 196                 server = _find_server(&uid);
 197                 if (!server) {
 198                         list_add(&newserver->server, &aliastree.serverlist);
 199                         server = newserver;
 200                 } else {
 201                         /* someone was faster */
 202                         _free_server(newserver);
 203                 }
 204         }
 205
 206         lcu = _find_lcu(server, &uid);
 207         if (!lcu) {
 208                 spin_unlock_irqrestore(&aliastree.lock, flags);
 209                 newlcu = _allocate_lcu(&uid);
 210                 if (IS_ERR(newlcu))
 211                         return PTR_ERR(newlcu);
 212                 spin_lock_irqsave(&aliastree.lock, flags);
 213                 lcu = _find_lcu(server, &uid);
 214                 if (!lcu) {
 215                         list_add(&newlcu->lcu, &server->lculist);
 216                         lcu = newlcu;
 217                 } else {
 218                         /* someone was faster */
 219                         _free_lcu(newlcu);
 220                 }
 221         }
 222         spin_lock(&lcu->lock);
 223         list_add(&device->alias_list, &lcu->inactive_devices);
 224         private->lcu = lcu;
 225         spin_unlock(&lcu->lock);
 226         spin_unlock_irqrestore(&aliastree.lock, flags);
 227
 228         return 0;
 229 }
 230
 231 /*
 232  * This function removes a device from the scope of alias management.
 233  * The complicated part is to make sure that it is not in use by
 234  * any of the workers. If necessary cancel the work.
 235  */
 236 void dasd_alias_disconnect_device_from_lcu(struct dasd_device *device)
 237 {
 238         struct dasd_eckd_private *private = device->private;
 239         unsigned long flags;
 240         struct alias_lcu *lcu;
 241         struct alias_server *server;
 242         int was_pending;
 243         struct dasd_uid uid;
 244
 245         lcu = private->lcu;
 246         /* nothing to do if already disconnected */
 247         if (!lcu)
 248                 return;
 249         device->discipline->get_uid(device, &uid);
 250         spin_lock_irqsave(&lcu->lock, flags);
 251         /* make sure that the workers don't use this device */
 252         if (device == lcu->suc_data.device) {
 253                 spin_unlock_irqrestore(&lcu->lock, flags);
 254                 cancel_work_sync(&lcu->suc_data.worker);
 255                 spin_lock_irqsave(&lcu->lock, flags);
 256                 if (device == lcu->suc_data.device) {
 257                         dasd_put_device(device);
 258                         lcu->suc_data.device = NULL;
 259                 }
 260         }
 261         was_pending = 0;
 262         if (device == lcu->ruac_data.device) {
 263                 spin_unlock_irqrestore(&lcu->lock, flags);
 264                 was_pending = 1;
 265                 cancel_delayed_work_sync(&lcu->ruac_data.dwork);
 266                 spin_lock_irqsave(&lcu->lock, flags);
 267                 if (device == lcu->ruac_data.device) {
 268                         dasd_put_device(device);
 269                         lcu->ruac_data.device = NULL;
 270                 }
 271         }
 272         private->lcu = NULL;
 273         spin_unlock_irqrestore(&lcu->lock, flags);
 274
 275         spin_lock_irqsave(&aliastree.lock, flags);
 276         spin_lock(&lcu->lock);
 277         list_del_init(&device->alias_list);
 278         if (list_empty(&lcu->grouplist) &&
 279             list_empty(&lcu->active_devices) &&
 280             list_empty(&lcu->inactive_devices)) {
 281                 list_del(&lcu->lcu);
 282                 spin_unlock(&lcu->lock);
 283                 _free_lcu(lcu);
 284                 lcu = NULL;
 285         } else {
 286                 if (was_pending)
 287                         _schedule_lcu_update(lcu, NULL);
 288                 spin_unlock(&lcu->lock);
 289         }
 290         server = _find_server(&uid);
 291         if (server && list_empty(&server->lculist)) {
 292                 list_del(&server->server);
 293                 _free_server(server);
 294         }
 295         spin_unlock_irqrestore(&aliastree.lock, flags);
 296 }
 297
 298 /*
 299  * This function assumes that the unit address configuration stored
 300  * in the lcu is up to date and will update the device uid before
 301  * adding it to a pav group.
 302  */
 303
 304 static int _add_device_to_lcu(struct alias_lcu *lcu,
 305                               struct dasd_device *device,
 306                               struct dasd_device *pos)
 307 {
 308
 309         struct dasd_eckd_private *private = device->private;
 310         struct alias_pav_group *group;
 311         struct dasd_uid uid;
 312
 313         spin_lock(get_ccwdev_lock(device->cdev));
 314         private->uid.type = lcu->uac->unit[private->uid.real_unit_addr].ua_type;
 315         private->uid.base_unit_addr =
 316                 lcu->uac->unit[private->uid.real_unit_addr].base_ua;
 317         uid = private->uid;
 318         spin_unlock(get_ccwdev_lock(device->cdev));
 319         /* if we have no PAV anyway, we don't need to bother with PAV groups */
 320         if (lcu->pav == NO_PAV) {
 321                 list_move(&device->alias_list, &lcu->active_devices);
 322                 return 0;
 323         }
 324         group = _find_group(lcu, &uid);
 325         if (!group) {
 326                 group = kzalloc(sizeof(*group), GFP_ATOMIC);
 327                 if (!group)
 328                         return -ENOMEM;
 329                 memcpy(group->uid.vendor, uid.vendor, sizeof(uid.vendor));
 330                 memcpy(group->uid.serial, uid.serial, sizeof(uid.serial));
 331                 group->uid.ssid = uid.ssid;
 332                 if (uid.type == UA_BASE_DEVICE)
 333                         group->uid.base_unit_addr = uid.real_unit_addr;
 334                 else
 335                         group->uid.base_unit_addr = uid.base_unit_addr;
 336                 memcpy(group->uid.vduit, uid.vduit, sizeof(uid.vduit));
 337                 INIT_LIST_HEAD(&group->group);
 338                 INIT_LIST_HEAD(&group->baselist);
 339                 INIT_LIST_HEAD(&group->aliaslist);
 340                 list_add(&group->group, &lcu->grouplist);
 341         }
 342         if (uid.type == UA_BASE_DEVICE)
 343                 list_move(&device->alias_list, &group->baselist);
 344         else
 345                 list_move(&device->alias_list, &group->aliaslist);
 346         private->pavgroup = group;
 347         return 0;
 348 };
 349
 350 static void _remove_device_from_lcu(struct alias_lcu *lcu,
 351                                     struct dasd_device *device)
 352 {
 353         struct dasd_eckd_private *private = device->private;
 354         struct alias_pav_group *group;
 355
 356         list_move(&device->alias_list, &lcu->inactive_devices);
 357         group = private->pavgroup;
 358         if (!group)
 359                 return;
 360         private->pavgroup = NULL;
 361         if (list_empty(&group->baselist) && list_empty(&group->aliaslist)) {
 362                 list_del(&group->group);
 363                 kfree(group);
 364                 return;
 365         }
 366         if (group->next == device)
 367                 group->next = NULL;
 368 };
 369
 370 static int
 371 suborder_not_supported(struct dasd_ccw_req *cqr)
 372 {
 373         char *sense;
 374         char reason;
 375         char msg_format;
 376         char msg_no;
 377
 378         /*
 379          * intrc values ENODEV, ENOLINK and EPERM
 380          * will be optained from sleep_on to indicate that no
 381          * IO operation can be started
 382          */
 383         if (cqr->intrc == -ENODEV)
 384                 return 1;
 385
 386         if (cqr->intrc == -ENOLINK)
 387                 return 1;
 388
 389         if (cqr->intrc == -EPERM)
 390                 return 1;
 391
 392         sense = dasd_get_sense(&cqr->irb);
 393         if (!sense)
 394                 return 0;
 395
 396         reason = sense[0];
 397         msg_format = (sense[7] & 0xF0);
 398         msg_no = (sense[7] & 0x0F);
 399
 400         /* command reject, Format 0 MSG 4 - invalid parameter */
 401         if ((reason == 0x80) && (msg_format == 0x00) && (msg_no == 0x04))
 402                 return 1;
 403
 404         return 0;
 405 }
 406
 407 static int read_unit_address_configuration(struct dasd_device *device,
 408                                            struct alias_lcu *lcu)
 409 {
 410         struct dasd_psf_prssd_data *prssdp;
 411         struct dasd_ccw_req *cqr;
 412         struct ccw1 *ccw;
 413         int rc;
 414         unsigned long flags;
 415
 416         cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, 1 /* PSF */ + 1 /* RSSD */,
 417                                    (sizeof(struct dasd_psf_prssd_data)),
 418                                    device, NULL);
 419         if (IS_ERR(cqr))
 420                 return PTR_ERR(cqr);
 421         cqr->startdev = device;
 422         cqr->memdev = device;
 423         clear_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags);
 424         cqr->retries = 10;
 425         cqr->expires = 20 * HZ;
 426
 427         /* Prepare for Read Subsystem Data */
 428         prssdp = (struct dasd_psf_prssd_data *) cqr->data;
 429         memset(prssdp, 0, sizeof(struct dasd_psf_prssd_data));
 430         prssdp->order = PSF_ORDER_PRSSD;
 431         prssdp->suborder = 0x0e;        /* Read unit address configuration */
 432         /* all other bytes of prssdp must be zero */
 433
 434         ccw = cqr->cpaddr;
 435         ccw->cmd_code = DASD_ECKD_CCW_PSF;
 436         ccw->count = sizeof(struct dasd_psf_prssd_data);
 437         ccw->flags |= CCW_FLAG_CC;
 438         ccw->cda = (__u32)virt_to_phys(prssdp);
 439
 440         /* Read Subsystem Data - feature codes */
 441         memset(lcu->uac, 0, sizeof(*(lcu->uac)));
 442
 443         ccw++;
 444         ccw->cmd_code = DASD_ECKD_CCW_RSSD;
 445         ccw->count = sizeof(*(lcu->uac));
 446         ccw->cda = (__u32)virt_to_phys(lcu->uac);
 447
 448         cqr->buildclk = get_tod_clock();
 449         cqr->status = DASD_CQR_FILLED;
 450
 451         /* need to unset flag here to detect race with summary unit check */
 452         spin_lock_irqsave(&lcu->lock, flags);
 453         lcu->flags &= ~NEED_UAC_UPDATE;
 454         spin_unlock_irqrestore(&lcu->lock, flags);
 455
 456         rc = dasd_sleep_on(cqr);
 457         if (!rc)
 458                 goto out;
 459
 460         if (suborder_not_supported(cqr)) {
 461                 /* suborder not supported or device unusable for IO */
 462                 rc = -EOPNOTSUPP;
 463         } else {
 464                 /* IO failed but should be retried */
 465                 spin_lock_irqsave(&lcu->lock, flags);
 466                 lcu->flags |= NEED_UAC_UPDATE;
 467                 spin_unlock_irqrestore(&lcu->lock, flags);
 468         }
 469 out:
 470         dasd_sfree_request(cqr, cqr->memdev);
 471         return rc;
 472 }
 473
 474 static int _lcu_update(struct dasd_device *refdev, struct alias_lcu *lcu)
 475 {
 476         unsigned long flags;
 477         struct alias_pav_group *pavgroup, *tempgroup;
 478         struct dasd_device *device, *tempdev;
 479         int i, rc;
 480         struct dasd_eckd_private *private;
 481
 482         spin_lock_irqsave(&lcu->lock, flags);
 483         list_for_each_entry_safe(pavgroup, tempgroup, &lcu->grouplist, group) {
 484                 list_for_each_entry_safe(device, tempdev, &pavgroup->baselist,
 485                                          alias_list) {
 486                         list_move(&device->alias_list, &lcu->active_devices);
 487                         private = device->private;
 488                         private->pavgroup = NULL;
 489                 }
 490                 list_for_each_entry_safe(device, tempdev, &pavgroup->aliaslist,
 491                                          alias_list) {
 492                         list_move(&device->alias_list, &lcu->active_devices);
 493                         private = device->private;
 494                         private->pavgroup = NULL;
 495                 }
 496                 list_del(&pavgroup->group);
 497                 kfree(pavgroup);
 498         }
 499         spin_unlock_irqrestore(&lcu->lock, flags);
 500
 501         rc = read_unit_address_configuration(refdev, lcu);
 502         if (rc)
 503                 return rc;
 504
 505         spin_lock_irqsave(&lcu->lock, flags);
 506         /*
 507          * there is another update needed skip the remaining handling
 508          * the data might already be outdated
 509          * but especially do not add the device to an LCU with pending
 510          * update
 511          */
 512         if (lcu->flags & NEED_UAC_UPDATE)
 513                 goto out;
 514         lcu->pav = NO_PAV;
 515         for (i = 0; i < MAX_DEVICES_PER_LCU; ++i) {
 516                 switch (lcu->uac->unit[i].ua_type) {
 517                 case UA_BASE_PAV_ALIAS:
 518                         lcu->pav = BASE_PAV;
 519                         break;
 520                 case UA_HYPER_PAV_ALIAS:
 521                         lcu->pav = HYPER_PAV;
 522                         break;
 523                 }
 524                 if (lcu->pav != NO_PAV)
 525                         break;
 526         }
 527
 528         list_for_each_entry_safe(device, tempdev, &lcu->active_devices,
 529                                  alias_list) {
 530                 _add_device_to_lcu(lcu, device, refdev);
 531         }
 532 out:
 533         spin_unlock_irqrestore(&lcu->lock, flags);
 534         return 0;
 535 }
 536
 537 static void lcu_update_work(struct work_struct *work)
 538 {
 539         struct alias_lcu *lcu;
 540         struct read_uac_work_data *ruac_data;
 541         struct dasd_device *device;
 542         unsigned long flags;
 543         int rc;
 544
 545         ruac_data = container_of(work, struct read_uac_work_data, dwork.work);
 546         lcu = container_of(ruac_data, struct alias_lcu, ruac_data);
 547         device = ruac_data->device;
 548         rc = _lcu_update(device, lcu);
 549         /*
 550          * Need to check flags again, as there could have been another
 551          * prepare_update or a new device a new device while we were still
 552          * processing the data
 553          */
 554         spin_lock_irqsave(&lcu->lock, flags);
 555         if ((rc && (rc != -EOPNOTSUPP)) || (lcu->flags & NEED_UAC_UPDATE)) {
 556                 DBF_DEV_EVENT(DBF_WARNING, device, "could not update"
 557                             " alias data in lcu (rc = %d), retry later", rc);
 558                 if (!schedule_delayed_work(&lcu->ruac_data.dwork, 30*HZ))
 559                         dasd_put_device(device);
 560         } else {
 561                 dasd_put_device(device);
 562                 lcu->ruac_data.device = NULL;
 563                 lcu->flags &= ~UPDATE_PENDING;
 564         }
 565         spin_unlock_irqrestore(&lcu->lock, flags);
 566 }
 567
 568 static int _schedule_lcu_update(struct alias_lcu *lcu,
 569                                 struct dasd_device *device)
 570 {
 571         struct dasd_device *usedev = NULL;
 572         struct alias_pav_group *group;
 573
 574         lcu->flags |= NEED_UAC_UPDATE;
 575         if (lcu->ruac_data.device) {
 576                 /* already scheduled or running */
 577                 return 0;
 578         }
 579         if (device && !list_empty(&device->alias_list))
 580                 usedev = device;
 581
 582         if (!usedev && !list_empty(&lcu->grouplist)) {
 583                 group = list_first_entry(&lcu->grouplist,
 584                                          struct alias_pav_group, group);
 585                 if (!list_empty(&group->baselist))
 586                         usedev = list_first_entry(&group->baselist,
 587                                                   struct dasd_device,
 588                                                   alias_list);
 589                 else if (!list_empty(&group->aliaslist))
 590                         usedev = list_first_entry(&group->aliaslist,
 591                                                   struct dasd_device,
 592                                                   alias_list);
 593         }
 594         if (!usedev && !list_empty(&lcu->active_devices)) {
 595                 usedev = list_first_entry(&lcu->active_devices,
 596                                           struct dasd_device, alias_list);
 597         }
 598         /*
 599          * if we haven't found a proper device yet, give up for now, the next
 600          * device that will be set active will trigger an lcu update
 601          */
 602         if (!usedev)
 603                 return -EINVAL;
 604         dasd_get_device(usedev);
 605         lcu->ruac_data.device = usedev;
 606         if (!schedule_delayed_work(&lcu->ruac_data.dwork, 0))
 607                 dasd_put_device(usedev);
 608         return 0;
 609 }
 610
 611 int dasd_alias_add_device(struct dasd_device *device)
 612 {
 613         struct dasd_eckd_private *private = device->private;
 614         __u8 uaddr = private->uid.real_unit_addr;
 615         struct alias_lcu *lcu = private->lcu;
 616         unsigned long flags;
 617         int rc;
 618
 619         rc = 0;
 620         spin_lock_irqsave(&lcu->lock, flags);
 621         /*
 622          * Check if device and lcu type differ. If so, the uac data may be
 623          * outdated and needs to be updated.
 624          */
 625         if (private->uid.type !=  lcu->uac->unit[uaddr].ua_type) {
 626                 lcu->flags |= UPDATE_PENDING;
 627                 DBF_DEV_EVENT(DBF_WARNING, device, "%s",
 628                               "uid type mismatch - trigger rescan");
 629         }
 630         if (!(lcu->flags & UPDATE_PENDING)) {
 631                 rc = _add_device_to_lcu(lcu, device, device);
 632                 if (rc)
 633                         lcu->flags |= UPDATE_PENDING;
 634         }
 635         if (lcu->flags & UPDATE_PENDING) {
 636                 list_move(&device->alias_list, &lcu->active_devices);
 637                 private->pavgroup = NULL;
 638                 _schedule_lcu_update(lcu, device);
 639         }
 640         spin_unlock_irqrestore(&lcu->lock, flags);
 641         return rc;
 642 }
 643
 644 int dasd_alias_update_add_device(struct dasd_device *device)
 645 {
 646         struct dasd_eckd_private *private = device->private;
 647
 648         private->lcu->flags |= UPDATE_PENDING;
 649         return dasd_alias_add_device(device);
 650 }
 651
 652 int dasd_alias_remove_device(struct dasd_device *device)
 653 {
 654         struct dasd_eckd_private *private = device->private;
 655         struct alias_lcu *lcu = private->lcu;
 656         unsigned long flags;
 657
 658         /* nothing to do if already removed */
 659         if (!lcu)
 660                 return 0;
 661         spin_lock_irqsave(&lcu->lock, flags);
 662         _remove_device_from_lcu(lcu, device);
 663         spin_unlock_irqrestore(&lcu->lock, flags);
 664         return 0;
 665 }
 666
 667 struct dasd_device *dasd_alias_get_start_dev(struct dasd_device *base_device)
 668 {
 669         struct dasd_eckd_private *alias_priv, *private = base_device->private;
 670         struct alias_lcu *lcu = private->lcu;
 671         struct dasd_device *alias_device;
 672         struct alias_pav_group *group;
 673         unsigned long flags;
 674
 675         if (!lcu)
 676                 return NULL;
 677         if (lcu->pav == NO_PAV ||
 678             lcu->flags & (NEED_UAC_UPDATE | UPDATE_PENDING))
 679                 return NULL;
 680         if (unlikely(!(private->features.feature[8] & 0x01))) {
 681                 /*
 682                  * PAV enabled but prefix not, very unlikely
 683                  * seems to be a lost pathgroup
 684                  * use base device to do IO
 685                  */
 686                 DBF_DEV_EVENT(DBF_ERR, base_device, "%s",
 687                               "Prefix not enabled with PAV enabled\n");
 688                 return NULL;
 689         }
 690
 691         spin_lock_irqsave(&lcu->lock, flags);
 692         group = private->pavgroup;
 693         if (!group) {
 694                 spin_unlock_irqrestore(&lcu->lock, flags);
 695                 return NULL;
 696         }
 697         alias_device = group->next;
 698         if (!alias_device) {
 699                 if (list_empty(&group->aliaslist)) {
 700                         spin_unlock_irqrestore(&lcu->lock, flags);
 701                         return NULL;
 702                 } else {
 703                         alias_device = list_first_entry(&group->aliaslist,
 704                                                         struct dasd_device,
 705                                                         alias_list);
 706                 }
 707         }
 708         if (list_is_last(&alias_device->alias_list, &group->aliaslist))
 709                 group->next = list_first_entry(&group->aliaslist,
 710                                                struct dasd_device, alias_list);
 711         else
 712                 group->next = list_first_entry(&alias_device->alias_list,
 713                                                struct dasd_device, alias_list);
 714         spin_unlock_irqrestore(&lcu->lock, flags);
 715         alias_priv = alias_device->private;
 716         if ((alias_priv->count < private->count) && !alias_device->stopped &&
 717             !test_bit(DASD_FLAG_OFFLINE, &alias_device->flags))
 718                 return alias_device;
 719         else
 720                 return NULL;
 721 }
 722
 723 /*
 724  * Summary unit check handling depends on the way alias devices
 725  * are handled so it is done here rather then in dasd_eckd.c
 726  */
 727 static int reset_summary_unit_check(struct alias_lcu *lcu,
 728                                     struct dasd_device *device,
 729                                     char reason)
 730 {
 731         struct dasd_ccw_req *cqr;
 732         int rc = 0;
 733         struct ccw1 *ccw;
 734
 735         cqr = lcu->rsu_cqr;
 736         memcpy((char *) &cqr->magic, "ECKD", 4);
 737         ASCEBC((char *) &cqr->magic, 4);
 738         ccw = cqr->cpaddr;
 739         ccw->cmd_code = DASD_ECKD_CCW_RSCK;
 740         ccw->flags = CCW_FLAG_SLI;
 741         ccw->count = 16;
 742         ccw->cda = (__u32)virt_to_phys(cqr->data);
 743         ((char *)cqr->data)[0] = reason;
 744
 745         clear_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags);
 746         cqr->retries = 255;     /* set retry counter to enable basic ERP */
 747         cqr->startdev = device;
 748         cqr->memdev = device;
 749         cqr->block = NULL;
 750         cqr->expires = 5 * HZ;
 751         cqr->buildclk = get_tod_clock();
 752         cqr->status = DASD_CQR_FILLED;
 753
 754         rc = dasd_sleep_on_immediatly(cqr);
 755         return rc;
 756 }
 757
 758 static void _restart_all_base_devices_on_lcu(struct alias_lcu *lcu)
 759 {
 760         struct alias_pav_group *pavgroup;
 761         struct dasd_device *device;
 762         struct dasd_eckd_private *private;
 763
 764         /* active and inactive list can contain alias as well as base devices */
 765         list_for_each_entry(device, &lcu->active_devices, alias_list) {
 766                 private = device->private;
 767                 if (private->uid.type != UA_BASE_DEVICE)
 768                         continue;
 769                 dasd_schedule_block_bh(device->block);
 770                 dasd_schedule_device_bh(device);
 771         }
 772         list_for_each_entry(device, &lcu->inactive_devices, alias_list) {
 773                 private = device->private;
 774                 if (private->uid.type != UA_BASE_DEVICE)
 775                         continue;
 776                 dasd_schedule_block_bh(device->block);
 777                 dasd_schedule_device_bh(device);
 778         }
 779         list_for_each_entry(pavgroup, &lcu->grouplist, group) {
 780                 list_for_each_entry(device, &pavgroup->baselist, alias_list) {
 781                         dasd_schedule_block_bh(device->block);
 782                         dasd_schedule_device_bh(device);
 783                 }
 784         }
 785 }
 786
 787 static void flush_all_alias_devices_on_lcu(struct alias_lcu *lcu)
 788 {
 789         struct alias_pav_group *pavgroup;
 790         struct dasd_device *device, *temp;
 791         struct dasd_eckd_private *private;
 792         unsigned long flags;
 793         LIST_HEAD(active);
 794
 795         /*
 796          * Problem here ist that dasd_flush_device_queue may wait
 797          * for termination of a request to complete. We can't keep
 798          * the lcu lock during that time, so we must assume that
 799          * the lists may have changed.
 800          * Idea: first gather all active alias devices in a separate list,
 801          * then flush the first element of this list unlocked, and afterwards
 802          * check if it is still on the list before moving it to the
 803          * active_devices list.
 804          */
 805
 806         spin_lock_irqsave(&lcu->lock, flags);
 807         list_for_each_entry_safe(device, temp, &lcu->active_devices,
 808                                  alias_list) {
 809                 private = device->private;
 810                 if (private->uid.type == UA_BASE_DEVICE)
 811                         continue;
 812                 list_move(&device->alias_list, &active);
 813         }
 814
 815         list_for_each_entry(pavgroup, &lcu->grouplist, group) {
 816                 list_splice_init(&pavgroup->aliaslist, &active);
 817         }
 818         while (!list_empty(&active)) {
 819                 device = list_first_entry(&active, struct dasd_device,
 820                                           alias_list);
 821                 spin_unlock_irqrestore(&lcu->lock, flags);
 822                 dasd_flush_device_queue(device);
 823                 spin_lock_irqsave(&lcu->lock, flags);
 824                 /*
 825                  * only move device around if it wasn't moved away while we
 826                  * were waiting for the flush
 827                  */
 828                 if (device == list_first_entry(&active,
 829                                                struct dasd_device, alias_list)) {
 830                         list_move(&device->alias_list, &lcu->active_devices);
 831                         private = device->private;
 832                         private->pavgroup = NULL;
 833                 }
 834         }
 835         spin_unlock_irqrestore(&lcu->lock, flags);
 836 }
 837
 838 static void _stop_all_devices_on_lcu(struct alias_lcu *lcu)
 839 {
 840         struct alias_pav_group *pavgroup;
 841         struct dasd_device *device;
 842
 843         list_for_each_entry(device, &lcu->active_devices, alias_list) {
 844                 spin_lock(get_ccwdev_lock(device->cdev));
 845                 dasd_device_set_stop_bits(device, DASD_STOPPED_SU);
 846                 spin_unlock(get_ccwdev_lock(device->cdev));
 847         }
 848         list_for_each_entry(device, &lcu->inactive_devices, alias_list) {
 849                 spin_lock(get_ccwdev_lock(device->cdev));
 850                 dasd_device_set_stop_bits(device, DASD_STOPPED_SU);
 851                 spin_unlock(get_ccwdev_lock(device->cdev));
 852         }
 853         list_for_each_entry(pavgroup, &lcu->grouplist, group) {
 854                 list_for_each_entry(device, &pavgroup->baselist, alias_list) {
 855                         spin_lock(get_ccwdev_lock(device->cdev));
 856                         dasd_device_set_stop_bits(device, DASD_STOPPED_SU);
 857                         spin_unlock(get_ccwdev_lock(device->cdev));
 858                 }
 859                 list_for_each_entry(device, &pavgroup->aliaslist, alias_list) {
 860                         spin_lock(get_ccwdev_lock(device->cdev));
 861                         dasd_device_set_stop_bits(device, DASD_STOPPED_SU);
 862                         spin_unlock(get_ccwdev_lock(device->cdev));
 863                 }
 864         }
 865 }
 866
 867 static void _unstop_all_devices_on_lcu(struct alias_lcu *lcu)
 868 {
 869         struct alias_pav_group *pavgroup;
 870         struct dasd_device *device;
 871
 872         list_for_each_entry(device, &lcu->active_devices, alias_list) {
 873                 spin_lock(get_ccwdev_lock(device->cdev));
 874                 dasd_device_remove_stop_bits(device, DASD_STOPPED_SU);
 875                 spin_unlock(get_ccwdev_lock(device->cdev));
 876         }
 877         list_for_each_entry(device, &lcu->inactive_devices, alias_list) {
 878                 spin_lock(get_ccwdev_lock(device->cdev));
 879                 dasd_device_remove_stop_bits(device, DASD_STOPPED_SU);
 880                 spin_unlock(get_ccwdev_lock(device->cdev));
 881         }
 882         list_for_each_entry(pavgroup, &lcu->grouplist, group) {
 883                 list_for_each_entry(device, &pavgroup->baselist, alias_list) {
 884                         spin_lock(get_ccwdev_lock(device->cdev));
 885                         dasd_device_remove_stop_bits(device, DASD_STOPPED_SU);
 886                         spin_unlock(get_ccwdev_lock(device->cdev));
 887                 }
 888                 list_for_each_entry(device, &pavgroup->aliaslist, alias_list) {
 889                         spin_lock(get_ccwdev_lock(device->cdev));
 890                         dasd_device_remove_stop_bits(device, DASD_STOPPED_SU);
 891                         spin_unlock(get_ccwdev_lock(device->cdev));
 892                 }
 893         }
 894 }
 895
 896 static void summary_unit_check_handling_work(struct work_struct *work)
 897 {
 898         struct alias_lcu *lcu;
 899         struct summary_unit_check_work_data *suc_data;
 900         unsigned long flags;
 901         struct dasd_device *device;
 902
 903         suc_data = container_of(work, struct summary_unit_check_work_data,
 904                                 worker);
 905         lcu = container_of(suc_data, struct alias_lcu, suc_data);
 906         device = suc_data->device;
 907
 908         /* 1. flush alias devices */
 909         flush_all_alias_devices_on_lcu(lcu);
 910
 911         /* 2. reset summary unit check */
 912         spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
 913         dasd_device_remove_stop_bits(device,
 914                                      (DASD_STOPPED_SU | DASD_STOPPED_PENDING));
 915         spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
 916         reset_summary_unit_check(lcu, device, suc_data->reason);
 917
 918         spin_lock_irqsave(&lcu->lock, flags);
 919         _unstop_all_devices_on_lcu(lcu);
 920         _restart_all_base_devices_on_lcu(lcu);
 921         /* 3. read new alias configuration */
 922         _schedule_lcu_update(lcu, device);
 923         lcu->suc_data.device = NULL;
 924         dasd_put_device(device);
 925         spin_unlock_irqrestore(&lcu->lock, flags);
 926 }
 927
 928 void dasd_alias_handle_summary_unit_check(struct work_struct *work)
 929 {
 930         struct dasd_device *device = container_of(work, struct dasd_device,
 931                                                   suc_work);
 932         struct dasd_eckd_private *private = device->private;
 933         struct alias_lcu *lcu;
 934         unsigned long flags;
 935
 936         lcu = private->lcu;
 937         if (!lcu) {
 938                 DBF_DEV_EVENT(DBF_WARNING, device, "%s",
 939                             "device not ready to handle summary"
 940                             " unit check (no lcu structure)");
 941                 goto out;
 942         }
 943         spin_lock_irqsave(&lcu->lock, flags);
 944         /* If this device is about to be removed just return and wait for
 945          * the next interrupt on a different device
 946          */
 947         if (list_empty(&device->alias_list)) {
 948                 DBF_DEV_EVENT(DBF_WARNING, device, "%s",
 949                             "device is in offline processing,"
 950                             " don't do summary unit check handling");
 951                 goto out_unlock;
 952         }
 953         if (lcu->suc_data.device) {
 954                 /* already scheduled or running */
 955                 DBF_DEV_EVENT(DBF_WARNING, device, "%s",
 956                             "previous instance of summary unit check worker"
 957                             " still pending");
 958                 goto out_unlock;
 959         }
 960         _stop_all_devices_on_lcu(lcu);
 961         /* prepare for lcu_update */
 962         lcu->flags |= NEED_UAC_UPDATE | UPDATE_PENDING;
 963         lcu->suc_data.reason = private->suc_reason;
 964         lcu->suc_data.device = device;
 965         dasd_get_device(device);
 966         if (!schedule_work(&lcu->suc_data.worker))
 967                 dasd_put_device(device);
 968 out_unlock:
 969         spin_unlock_irqrestore(&lcu->lock, flags);
 970 out:
 971         clear_bit(DASD_FLAG_SUC, &device->flags);
 972         dasd_put_device(device);
 973 };