drivers/s390/block/dasd_alias.c

   1 /*
   2  * PAV alias management for the DASD ECKD discipline
   3  *
   4  * Copyright IBM Corp. 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 = device->private;
 189         unsigned long flags;
 190         struct alias_server *server, *newserver;
 191         struct alias_lcu *lcu, *newlcu;
 192         struct dasd_uid uid;
 193
 194         device->discipline->get_uid(device, &uid);
 195         spin_lock_irqsave(&aliastree.lock, flags);
 196         server = _find_server(&uid);
 197         if (!server) {
 198                 spin_unlock_irqrestore(&aliastree.lock, flags);
 199                 newserver = _allocate_server(&uid);
 200                 if (IS_ERR(newserver))
 201                         return PTR_ERR(newserver);
 202                 spin_lock_irqsave(&aliastree.lock, flags);
 203                 server = _find_server(&uid);
 204                 if (!server) {
 205                         list_add(&newserver->server, &aliastree.serverlist);
 206                         server = newserver;
 207                 } else {
 208                         /* someone was faster */
 209                         _free_server(newserver);
 210                 }
 211         }
 212
 213         lcu = _find_lcu(server, &uid);
 214         if (!lcu) {
 215                 spin_unlock_irqrestore(&aliastree.lock, flags);
 216                 newlcu = _allocate_lcu(&uid);
 217                 if (IS_ERR(newlcu))
 218                         return PTR_ERR(newlcu);
 219                 spin_lock_irqsave(&aliastree.lock, flags);
 220                 lcu = _find_lcu(server, &uid);
 221                 if (!lcu) {
 222                         list_add(&newlcu->lcu, &server->lculist);
 223                         lcu = newlcu;
 224                 } else {
 225                         /* someone was faster */
 226                         _free_lcu(newlcu);
 227                 }
 228         }
 229         spin_lock(&lcu->lock);
 230         list_add(&device->alias_list, &lcu->inactive_devices);
 231         private->lcu = lcu;
 232         spin_unlock(&lcu->lock);
 233         spin_unlock_irqrestore(&aliastree.lock, flags);
 234
 235         return 0;
 236 }
 237
 238 /*
 239  * This function removes a device from the scope of alias management.
 240  * The complicated part is to make sure that it is not in use by
 241  * any of the workers. If necessary cancel the work.
 242  */
 243 void dasd_alias_disconnect_device_from_lcu(struct dasd_device *device)
 244 {
 245         struct dasd_eckd_private *private = device->private;
 246         unsigned long flags;
 247         struct alias_lcu *lcu;
 248         struct alias_server *server;
 249         int was_pending;
 250         struct dasd_uid uid;
 251
 252         lcu = private->lcu;
 253         /* nothing to do if already disconnected */
 254         if (!lcu)
 255                 return;
 256         device->discipline->get_uid(device, &uid);
 257         spin_lock_irqsave(&lcu->lock, flags);
 258         list_del_init(&device->alias_list);
 259         /* make sure that the workers don't use this device */
 260         if (device == lcu->suc_data.device) {
 261                 spin_unlock_irqrestore(&lcu->lock, flags);
 262                 cancel_work_sync(&lcu->suc_data.worker);
 263                 spin_lock_irqsave(&lcu->lock, flags);
 264                 if (device == lcu->suc_data.device) {
 265                         dasd_put_device(device);
 266                         lcu->suc_data.device = NULL;
 267                 }
 268         }
 269         was_pending = 0;
 270         if (device == lcu->ruac_data.device) {
 271                 spin_unlock_irqrestore(&lcu->lock, flags);
 272                 was_pending = 1;
 273                 cancel_delayed_work_sync(&lcu->ruac_data.dwork);
 274                 spin_lock_irqsave(&lcu->lock, flags);
 275                 if (device == lcu->ruac_data.device) {
 276                         dasd_put_device(device);
 277                         lcu->ruac_data.device = NULL;
 278                 }
 279         }
 280         private->lcu = NULL;
 281         spin_unlock_irqrestore(&lcu->lock, flags);
 282
 283         spin_lock_irqsave(&aliastree.lock, flags);
 284         spin_lock(&lcu->lock);
 285         if (list_empty(&lcu->grouplist) &&
 286             list_empty(&lcu->active_devices) &&
 287             list_empty(&lcu->inactive_devices)) {
 288                 list_del(&lcu->lcu);
 289                 spin_unlock(&lcu->lock);
 290                 _free_lcu(lcu);
 291                 lcu = NULL;
 292         } else {
 293                 if (was_pending)
 294                         _schedule_lcu_update(lcu, NULL);
 295                 spin_unlock(&lcu->lock);
 296         }
 297         server = _find_server(&uid);
 298         if (server && list_empty(&server->lculist)) {
 299                 list_del(&server->server);
 300                 _free_server(server);
 301         }
 302         spin_unlock_irqrestore(&aliastree.lock, flags);
 303 }
 304
 305 /*
 306  * This function assumes that the unit address configuration stored
 307  * in the lcu is up to date and will update the device uid before
 308  * adding it to a pav group.
 309  */
 310
 311 static int _add_device_to_lcu(struct alias_lcu *lcu,
 312                               struct dasd_device *device,
 313                               struct dasd_device *pos)
 314 {
 315
 316         struct dasd_eckd_private *private = device->private;
 317         struct alias_pav_group *group;
 318         struct dasd_uid uid;
 319
 320         private->uid.type = lcu->uac->unit[private->uid.real_unit_addr].ua_type;
 321         private->uid.base_unit_addr =
 322                 lcu->uac->unit[private->uid.real_unit_addr].base_ua;
 323         uid = private->uid;
 324
 325         /* if we have no PAV anyway, we don't need to bother with PAV groups */
 326         if (lcu->pav == NO_PAV) {
 327                 list_move(&device->alias_list, &lcu->active_devices);
 328                 return 0;
 329         }
 330
 331         group = _find_group(lcu, &uid);
 332         if (!group) {
 333                 group = kzalloc(sizeof(*group), GFP_ATOMIC);
 334                 if (!group)
 335                         return -ENOMEM;
 336                 memcpy(group->uid.vendor, uid.vendor, sizeof(uid.vendor));
 337                 memcpy(group->uid.serial, uid.serial, sizeof(uid.serial));
 338                 group->uid.ssid = uid.ssid;
 339                 if (uid.type == UA_BASE_DEVICE)
 340                         group->uid.base_unit_addr = uid.real_unit_addr;
 341                 else
 342                         group->uid.base_unit_addr = uid.base_unit_addr;
 343                 memcpy(group->uid.vduit, uid.vduit, sizeof(uid.vduit));
 344                 INIT_LIST_HEAD(&group->group);
 345                 INIT_LIST_HEAD(&group->baselist);
 346                 INIT_LIST_HEAD(&group->aliaslist);
 347                 list_add(&group->group, &lcu->grouplist);
 348         }
 349         if (uid.type == UA_BASE_DEVICE)
 350                 list_move(&device->alias_list, &group->baselist);
 351         else
 352                 list_move(&device->alias_list, &group->aliaslist);
 353         private->pavgroup = group;
 354         return 0;
 355 };
 356
 357 static void _remove_device_from_lcu(struct alias_lcu *lcu,
 358                                     struct dasd_device *device)
 359 {
 360         struct dasd_eckd_private *private = device->private;
 361         struct alias_pav_group *group;
 362
 363         list_move(&device->alias_list, &lcu->inactive_devices);
 364         group = private->pavgroup;
 365         if (!group)
 366                 return;
 367         private->pavgroup = NULL;
 368         if (list_empty(&group->baselist) && list_empty(&group->aliaslist)) {
 369                 list_del(&group->group);
 370                 kfree(group);
 371                 return;
 372         }
 373         if (group->next == device)
 374                 group->next = NULL;
 375 };
 376
 377 static int
 378 suborder_not_supported(struct dasd_ccw_req *cqr)
 379 {
 380         char *sense;
 381         char reason;
 382         char msg_format;
 383         char msg_no;
 384
 385         sense = dasd_get_sense(&cqr->irb);
 386         if (!sense)
 387                 return 0;
 388
 389         reason = sense[0];
 390         msg_format = (sense[7] & 0xF0);
 391         msg_no = (sense[7] & 0x0F);
 392
 393         /* command reject, Format 0 MSG 4 - invalid parameter */
 394         if ((reason == 0x80) && (msg_format == 0x00) && (msg_no == 0x04))
 395                 return 1;
 396
 397         return 0;
 398 }
 399
 400 /*
 401  * This function tries to lock all devices on an lcu via trylock
 402  * return NULL on success otherwise return first failed device
 403  */
 404 static struct dasd_device *_trylock_all_devices_on_lcu(struct alias_lcu *lcu,
 405                                                       struct dasd_device *pos)
 406
 407 {
 408         struct alias_pav_group *pavgroup;
 409         struct dasd_device *device;
 410
 411         list_for_each_entry(device, &lcu->active_devices, alias_list) {
 412                 if (device == pos)
 413                         continue;
 414                 if (!spin_trylock(get_ccwdev_lock(device->cdev)))
 415                         return device;
 416         }
 417         list_for_each_entry(device, &lcu->inactive_devices, alias_list) {
 418                 if (device == pos)
 419                         continue;
 420                 if (!spin_trylock(get_ccwdev_lock(device->cdev)))
 421                         return device;
 422         }
 423         list_for_each_entry(pavgroup, &lcu->grouplist, group) {
 424                 list_for_each_entry(device, &pavgroup->baselist, alias_list) {
 425                         if (device == pos)
 426                                 continue;
 427                         if (!spin_trylock(get_ccwdev_lock(device->cdev)))
 428                                 return device;
 429                 }
 430                 list_for_each_entry(device, &pavgroup->aliaslist, alias_list) {
 431                         if (device == pos)
 432                                 continue;
 433                         if (!spin_trylock(get_ccwdev_lock(device->cdev)))
 434                                 return device;
 435                 }
 436         }
 437         return NULL;
 438 }
 439
 440 /*
 441  * unlock all devices except the one that is specified as pos
 442  * stop if enddev is specified and reached
 443  */
 444 static void _unlock_all_devices_on_lcu(struct alias_lcu *lcu,
 445                                        struct dasd_device *pos,
 446                                        struct dasd_device *enddev)
 447
 448 {
 449         struct alias_pav_group *pavgroup;
 450         struct dasd_device *device;
 451
 452         list_for_each_entry(device, &lcu->active_devices, alias_list) {
 453                 if (device == pos)
 454                         continue;
 455                 if (device == enddev)
 456                         return;
 457                 spin_unlock(get_ccwdev_lock(device->cdev));
 458         }
 459         list_for_each_entry(device, &lcu->inactive_devices, alias_list) {
 460                 if (device == pos)
 461                         continue;
 462                 if (device == enddev)
 463                         return;
 464                 spin_unlock(get_ccwdev_lock(device->cdev));
 465         }
 466         list_for_each_entry(pavgroup, &lcu->grouplist, group) {
 467                 list_for_each_entry(device, &pavgroup->baselist, alias_list) {
 468                         if (device == pos)
 469                                 continue;
 470                         if (device == enddev)
 471                                 return;
 472                         spin_unlock(get_ccwdev_lock(device->cdev));
 473                 }
 474                 list_for_each_entry(device, &pavgroup->aliaslist, alias_list) {
 475                         if (device == pos)
 476                                 continue;
 477                         if (device == enddev)
 478                                 return;
 479                         spin_unlock(get_ccwdev_lock(device->cdev));
 480                 }
 481         }
 482 }
 483
 484 /*
 485  *  this function is needed because the locking order
 486  *  device lock -> lcu lock
 487  *  needs to be assured when iterating over devices in an LCU
 488  *
 489  *  if a device is specified in pos then the device lock is already hold
 490  */
 491 static void _trylock_and_lock_lcu_irqsave(struct alias_lcu *lcu,
 492                                           struct dasd_device *pos,
 493                                           unsigned long *flags)
 494 {
 495         struct dasd_device *failed;
 496
 497         do {
 498                 spin_lock_irqsave(&lcu->lock, *flags);
 499                 failed = _trylock_all_devices_on_lcu(lcu, pos);
 500                 if (failed) {
 501                         _unlock_all_devices_on_lcu(lcu, pos, failed);
 502                         spin_unlock_irqrestore(&lcu->lock, *flags);
 503                         cpu_relax();
 504                 }
 505         } while (failed);
 506 }
 507
 508 static void _trylock_and_lock_lcu(struct alias_lcu *lcu,
 509                                   struct dasd_device *pos)
 510 {
 511         struct dasd_device *failed;
 512
 513         do {
 514                 spin_lock(&lcu->lock);
 515                 failed = _trylock_all_devices_on_lcu(lcu, pos);
 516                 if (failed) {
 517                         _unlock_all_devices_on_lcu(lcu, pos, failed);
 518                         spin_unlock(&lcu->lock);
 519                         cpu_relax();
 520                 }
 521         } while (failed);
 522 }
 523
 524 static int read_unit_address_configuration(struct dasd_device *device,
 525                                            struct alias_lcu *lcu)
 526 {
 527         struct dasd_psf_prssd_data *prssdp;
 528         struct dasd_ccw_req *cqr;
 529         struct ccw1 *ccw;
 530         int rc;
 531         unsigned long flags;
 532
 533         cqr = dasd_kmalloc_request(DASD_ECKD_MAGIC, 1 /* PSF */ + 1 /* RSSD */,
 534                                    (sizeof(struct dasd_psf_prssd_data)),
 535                                    device);
 536         if (IS_ERR(cqr))
 537                 return PTR_ERR(cqr);
 538         cqr->startdev = device;
 539         cqr->memdev = device;
 540         clear_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags);
 541         cqr->retries = 10;
 542         cqr->expires = 20 * HZ;
 543
 544         /* Prepare for Read Subsystem Data */
 545         prssdp = (struct dasd_psf_prssd_data *) cqr->data;
 546         memset(prssdp, 0, sizeof(struct dasd_psf_prssd_data));
 547         prssdp->order = PSF_ORDER_PRSSD;
 548         prssdp->suborder = 0x0e;        /* Read unit address configuration */
 549         /* all other bytes of prssdp must be zero */
 550
 551         ccw = cqr->cpaddr;
 552         ccw->cmd_code = DASD_ECKD_CCW_PSF;
 553         ccw->count = sizeof(struct dasd_psf_prssd_data);
 554         ccw->flags |= CCW_FLAG_CC;
 555         ccw->cda = (__u32)(addr_t) prssdp;
 556
 557         /* Read Subsystem Data - feature codes */
 558         memset(lcu->uac, 0, sizeof(*(lcu->uac)));
 559
 560         ccw++;
 561         ccw->cmd_code = DASD_ECKD_CCW_RSSD;
 562         ccw->count = sizeof(*(lcu->uac));
 563         ccw->cda = (__u32)(addr_t) lcu->uac;
 564
 565         cqr->buildclk = get_tod_clock();
 566         cqr->status = DASD_CQR_FILLED;
 567
 568         /* need to unset flag here to detect race with summary unit check */
 569         spin_lock_irqsave(&lcu->lock, flags);
 570         lcu->flags &= ~NEED_UAC_UPDATE;
 571         spin_unlock_irqrestore(&lcu->lock, flags);
 572
 573         do {
 574                 rc = dasd_sleep_on(cqr);
 575                 if (rc && suborder_not_supported(cqr))
 576                         return -EOPNOTSUPP;
 577         } while (rc && (cqr->retries > 0));
 578         if (rc) {
 579                 spin_lock_irqsave(&lcu->lock, flags);
 580                 lcu->flags |= NEED_UAC_UPDATE;
 581                 spin_unlock_irqrestore(&lcu->lock, flags);
 582         }
 583         dasd_kfree_request(cqr, cqr->memdev);
 584         return rc;
 585 }
 586
 587 static int _lcu_update(struct dasd_device *refdev, struct alias_lcu *lcu)
 588 {
 589         unsigned long flags;
 590         struct alias_pav_group *pavgroup, *tempgroup;
 591         struct dasd_device *device, *tempdev;
 592         int i, rc;
 593         struct dasd_eckd_private *private;
 594
 595         spin_lock_irqsave(&lcu->lock, flags);
 596         list_for_each_entry_safe(pavgroup, tempgroup, &lcu->grouplist, group) {
 597                 list_for_each_entry_safe(device, tempdev, &pavgroup->baselist,
 598                                          alias_list) {
 599                         list_move(&device->alias_list, &lcu->active_devices);
 600                         private = device->private;
 601                         private->pavgroup = NULL;
 602                 }
 603                 list_for_each_entry_safe(device, tempdev, &pavgroup->aliaslist,
 604                                          alias_list) {
 605                         list_move(&device->alias_list, &lcu->active_devices);
 606                         private = device->private;
 607                         private->pavgroup = NULL;
 608                 }
 609                 list_del(&pavgroup->group);
 610                 kfree(pavgroup);
 611         }
 612         spin_unlock_irqrestore(&lcu->lock, flags);
 613
 614         rc = read_unit_address_configuration(refdev, lcu);
 615         if (rc)
 616                 return rc;
 617
 618         _trylock_and_lock_lcu_irqsave(lcu, NULL, &flags);
 619         lcu->pav = NO_PAV;
 620         for (i = 0; i < MAX_DEVICES_PER_LCU; ++i) {
 621                 switch (lcu->uac->unit[i].ua_type) {
 622                 case UA_BASE_PAV_ALIAS:
 623                         lcu->pav = BASE_PAV;
 624                         break;
 625                 case UA_HYPER_PAV_ALIAS:
 626                         lcu->pav = HYPER_PAV;
 627                         break;
 628                 }
 629                 if (lcu->pav != NO_PAV)
 630                         break;
 631         }
 632
 633         list_for_each_entry_safe(device, tempdev, &lcu->active_devices,
 634                                  alias_list) {
 635                 _add_device_to_lcu(lcu, device, refdev);
 636         }
 637         _unlock_all_devices_on_lcu(lcu, NULL, NULL);
 638         spin_unlock_irqrestore(&lcu->lock, flags);
 639         return 0;
 640 }
 641
 642 static void lcu_update_work(struct work_struct *work)
 643 {
 644         struct alias_lcu *lcu;
 645         struct read_uac_work_data *ruac_data;
 646         struct dasd_device *device;
 647         unsigned long flags;
 648         int rc;
 649
 650         ruac_data = container_of(work, struct read_uac_work_data, dwork.work);
 651         lcu = container_of(ruac_data, struct alias_lcu, ruac_data);
 652         device = ruac_data->device;
 653         rc = _lcu_update(device, lcu);
 654         /*
 655          * Need to check flags again, as there could have been another
 656          * prepare_update or a new device a new device while we were still
 657          * processing the data
 658          */
 659         spin_lock_irqsave(&lcu->lock, flags);
 660         if ((rc && (rc != -EOPNOTSUPP)) || (lcu->flags & NEED_UAC_UPDATE)) {
 661                 DBF_DEV_EVENT(DBF_WARNING, device, "could not update"
 662                             " alias data in lcu (rc = %d), retry later", rc);
 663                 if (!schedule_delayed_work(&lcu->ruac_data.dwork, 30*HZ))
 664                         dasd_put_device(device);
 665         } else {
 666                 dasd_put_device(device);
 667                 lcu->ruac_data.device = NULL;
 668                 lcu->flags &= ~UPDATE_PENDING;
 669         }
 670         spin_unlock_irqrestore(&lcu->lock, flags);
 671 }
 672
 673 static int _schedule_lcu_update(struct alias_lcu *lcu,
 674                                 struct dasd_device *device)
 675 {
 676         struct dasd_device *usedev = NULL;
 677         struct alias_pav_group *group;
 678
 679         lcu->flags |= NEED_UAC_UPDATE;
 680         if (lcu->ruac_data.device) {
 681                 /* already scheduled or running */
 682                 return 0;
 683         }
 684         if (device && !list_empty(&device->alias_list))
 685                 usedev = device;
 686
 687         if (!usedev && !list_empty(&lcu->grouplist)) {
 688                 group = list_first_entry(&lcu->grouplist,
 689                                          struct alias_pav_group, group);
 690                 if (!list_empty(&group->baselist))
 691                         usedev = list_first_entry(&group->baselist,
 692                                                   struct dasd_device,
 693                                                   alias_list);
 694                 else if (!list_empty(&group->aliaslist))
 695                         usedev = list_first_entry(&group->aliaslist,
 696                                                   struct dasd_device,
 697                                                   alias_list);
 698         }
 699         if (!usedev && !list_empty(&lcu->active_devices)) {
 700                 usedev = list_first_entry(&lcu->active_devices,
 701                                           struct dasd_device, alias_list);
 702         }
 703         /*
 704          * if we haven't found a proper device yet, give up for now, the next
 705          * device that will be set active will trigger an lcu update
 706          */
 707         if (!usedev)
 708                 return -EINVAL;
 709         dasd_get_device(usedev);
 710         lcu->ruac_data.device = usedev;
 711         if (!schedule_delayed_work(&lcu->ruac_data.dwork, 0))
 712                 dasd_put_device(usedev);
 713         return 0;
 714 }
 715
 716 int dasd_alias_add_device(struct dasd_device *device)
 717 {
 718         struct dasd_eckd_private *private = device->private;
 719         struct alias_lcu *lcu;
 720         unsigned long flags;
 721         int rc;
 722
 723         lcu = private->lcu;
 724         rc = 0;
 725         spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
 726         spin_lock(&lcu->lock);
 727         if (!(lcu->flags & UPDATE_PENDING)) {
 728                 rc = _add_device_to_lcu(lcu, device, device);
 729                 if (rc)
 730                         lcu->flags |= UPDATE_PENDING;
 731         }
 732         if (lcu->flags & UPDATE_PENDING) {
 733                 list_move(&device->alias_list, &lcu->active_devices);
 734                 _schedule_lcu_update(lcu, device);
 735         }
 736         spin_unlock(&lcu->lock);
 737         spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
 738         return rc;
 739 }
 740
 741 int dasd_alias_update_add_device(struct dasd_device *device)
 742 {
 743         struct dasd_eckd_private *private = device->private;
 744
 745         private->lcu->flags |= UPDATE_PENDING;
 746         return dasd_alias_add_device(device);
 747 }
 748
 749 int dasd_alias_remove_device(struct dasd_device *device)
 750 {
 751         struct dasd_eckd_private *private = device->private;
 752         struct alias_lcu *lcu = private->lcu;
 753         unsigned long flags;
 754
 755         /* nothing to do if already removed */
 756         if (!lcu)
 757                 return 0;
 758         spin_lock_irqsave(&lcu->lock, flags);
 759         _remove_device_from_lcu(lcu, device);
 760         spin_unlock_irqrestore(&lcu->lock, flags);
 761         return 0;
 762 }
 763
 764 struct dasd_device *dasd_alias_get_start_dev(struct dasd_device *base_device)
 765 {
 766         struct dasd_eckd_private *alias_priv, *private = base_device->private;
 767         struct alias_pav_group *group = private->pavgroup;
 768         struct alias_lcu *lcu = private->lcu;
 769         struct dasd_device *alias_device;
 770         unsigned long flags;
 771
 772         if (!group || !lcu)
 773                 return NULL;
 774         if (lcu->pav == NO_PAV ||
 775             lcu->flags & (NEED_UAC_UPDATE | UPDATE_PENDING))
 776                 return NULL;
 777         if (unlikely(!(private->features.feature[8] & 0x01))) {
 778                 /*
 779                  * PAV enabled but prefix not, very unlikely
 780                  * seems to be a lost pathgroup
 781                  * use base device to do IO
 782                  */
 783                 DBF_DEV_EVENT(DBF_ERR, base_device, "%s",
 784                               "Prefix not enabled with PAV enabled\n");
 785                 return NULL;
 786         }
 787
 788         spin_lock_irqsave(&lcu->lock, flags);
 789         alias_device = group->next;
 790         if (!alias_device) {
 791                 if (list_empty(&group->aliaslist)) {
 792                         spin_unlock_irqrestore(&lcu->lock, flags);
 793                         return NULL;
 794                 } else {
 795                         alias_device = list_first_entry(&group->aliaslist,
 796                                                         struct dasd_device,
 797                                                         alias_list);
 798                 }
 799         }
 800         if (list_is_last(&alias_device->alias_list, &group->aliaslist))
 801                 group->next = list_first_entry(&group->aliaslist,
 802                                                struct dasd_device, alias_list);
 803         else
 804                 group->next = list_first_entry(&alias_device->alias_list,
 805                                                struct dasd_device, alias_list);
 806         spin_unlock_irqrestore(&lcu->lock, flags);
 807         alias_priv = alias_device->private;
 808         if ((alias_priv->count < private->count) && !alias_device->stopped &&
 809             !test_bit(DASD_FLAG_OFFLINE, &alias_device->flags))
 810                 return alias_device;
 811         else
 812                 return NULL;
 813 }
 814
 815 /*
 816  * Summary unit check handling depends on the way alias devices
 817  * are handled so it is done here rather then in dasd_eckd.c
 818  */
 819 static int reset_summary_unit_check(struct alias_lcu *lcu,
 820                                     struct dasd_device *device,
 821                                     char reason)
 822 {
 823         struct dasd_ccw_req *cqr;
 824         int rc = 0;
 825         struct ccw1 *ccw;
 826
 827         cqr = lcu->rsu_cqr;
 828         strncpy((char *) &cqr->magic, "ECKD", 4);
 829         ASCEBC((char *) &cqr->magic, 4);
 830         ccw = cqr->cpaddr;
 831         ccw->cmd_code = DASD_ECKD_CCW_RSCK;
 832         ccw->flags = CCW_FLAG_SLI;
 833         ccw->count = 16;
 834         ccw->cda = (__u32)(addr_t) cqr->data;
 835         ((char *)cqr->data)[0] = reason;
 836
 837         clear_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags);
 838         cqr->retries = 255;     /* set retry counter to enable basic ERP */
 839         cqr->startdev = device;
 840         cqr->memdev = device;
 841         cqr->block = NULL;
 842         cqr->expires = 5 * HZ;
 843         cqr->buildclk = get_tod_clock();
 844         cqr->status = DASD_CQR_FILLED;
 845
 846         rc = dasd_sleep_on_immediatly(cqr);
 847         return rc;
 848 }
 849
 850 static void _restart_all_base_devices_on_lcu(struct alias_lcu *lcu)
 851 {
 852         struct alias_pav_group *pavgroup;
 853         struct dasd_device *device;
 854         struct dasd_eckd_private *private;
 855
 856         /* active and inactive list can contain alias as well as base devices */
 857         list_for_each_entry(device, &lcu->active_devices, alias_list) {
 858                 private = device->private;
 859                 if (private->uid.type != UA_BASE_DEVICE)
 860                         continue;
 861                 dasd_schedule_block_bh(device->block);
 862                 dasd_schedule_device_bh(device);
 863         }
 864         list_for_each_entry(device, &lcu->inactive_devices, alias_list) {
 865                 private = device->private;
 866                 if (private->uid.type != UA_BASE_DEVICE)
 867                         continue;
 868                 dasd_schedule_block_bh(device->block);
 869                 dasd_schedule_device_bh(device);
 870         }
 871         list_for_each_entry(pavgroup, &lcu->grouplist, group) {
 872                 list_for_each_entry(device, &pavgroup->baselist, alias_list) {
 873                         dasd_schedule_block_bh(device->block);
 874                         dasd_schedule_device_bh(device);
 875                 }
 876         }
 877 }
 878
 879 static void flush_all_alias_devices_on_lcu(struct alias_lcu *lcu)
 880 {
 881         struct alias_pav_group *pavgroup;
 882         struct dasd_device *device, *temp;
 883         struct dasd_eckd_private *private;
 884         int rc;
 885         unsigned long flags;
 886         LIST_HEAD(active);
 887
 888         /*
 889          * Problem here ist that dasd_flush_device_queue may wait
 890          * for termination of a request to complete. We can't keep
 891          * the lcu lock during that time, so we must assume that
 892          * the lists may have changed.
 893          * Idea: first gather all active alias devices in a separate list,
 894          * then flush the first element of this list unlocked, and afterwards
 895          * check if it is still on the list before moving it to the
 896          * active_devices list.
 897          */
 898
 899         spin_lock_irqsave(&lcu->lock, flags);
 900         list_for_each_entry_safe(device, temp, &lcu->active_devices,
 901                                  alias_list) {
 902                 private = device->private;
 903                 if (private->uid.type == UA_BASE_DEVICE)
 904                         continue;
 905                 list_move(&device->alias_list, &active);
 906         }
 907
 908         list_for_each_entry(pavgroup, &lcu->grouplist, group) {
 909                 list_splice_init(&pavgroup->aliaslist, &active);
 910         }
 911         while (!list_empty(&active)) {
 912                 device = list_first_entry(&active, struct dasd_device,
 913                                           alias_list);
 914                 spin_unlock_irqrestore(&lcu->lock, flags);
 915                 rc = dasd_flush_device_queue(device);
 916                 spin_lock_irqsave(&lcu->lock, flags);
 917                 /*
 918                  * only move device around if it wasn't moved away while we
 919                  * were waiting for the flush
 920                  */
 921                 if (device == list_first_entry(&active,
 922                                                struct dasd_device, alias_list)) {
 923                         list_move(&device->alias_list, &lcu->active_devices);
 924                         private = device->private;
 925                         private->pavgroup = NULL;
 926                 }
 927         }
 928         spin_unlock_irqrestore(&lcu->lock, flags);
 929 }
 930
 931 static void _stop_all_devices_on_lcu(struct alias_lcu *lcu)
 932 {
 933         struct alias_pav_group *pavgroup;
 934         struct dasd_device *device;
 935
 936         list_for_each_entry(device, &lcu->active_devices, alias_list)
 937                 dasd_device_set_stop_bits(device, DASD_STOPPED_SU);
 938         list_for_each_entry(device, &lcu->inactive_devices, alias_list)
 939                 dasd_device_set_stop_bits(device, DASD_STOPPED_SU);
 940         list_for_each_entry(pavgroup, &lcu->grouplist, group) {
 941                 list_for_each_entry(device, &pavgroup->baselist, alias_list)
 942                         dasd_device_set_stop_bits(device, DASD_STOPPED_SU);
 943                 list_for_each_entry(device, &pavgroup->aliaslist, alias_list)
 944                         dasd_device_set_stop_bits(device, DASD_STOPPED_SU);
 945         }
 946 }
 947
 948 static void _unstop_all_devices_on_lcu(struct alias_lcu *lcu)
 949 {
 950         struct alias_pav_group *pavgroup;
 951         struct dasd_device *device;
 952
 953         list_for_each_entry(device, &lcu->active_devices, alias_list)
 954                 dasd_device_remove_stop_bits(device, DASD_STOPPED_SU);
 955         list_for_each_entry(device, &lcu->inactive_devices, alias_list)
 956                 dasd_device_remove_stop_bits(device, DASD_STOPPED_SU);
 957         list_for_each_entry(pavgroup, &lcu->grouplist, group) {
 958                 list_for_each_entry(device, &pavgroup->baselist, alias_list)
 959                         dasd_device_remove_stop_bits(device, DASD_STOPPED_SU);
 960                 list_for_each_entry(device, &pavgroup->aliaslist, alias_list)
 961                         dasd_device_remove_stop_bits(device, DASD_STOPPED_SU);
 962         }
 963 }
 964
 965 static void summary_unit_check_handling_work(struct work_struct *work)
 966 {
 967         struct alias_lcu *lcu;
 968         struct summary_unit_check_work_data *suc_data;
 969         unsigned long flags;
 970         struct dasd_device *device;
 971
 972         suc_data = container_of(work, struct summary_unit_check_work_data,
 973                                 worker);
 974         lcu = container_of(suc_data, struct alias_lcu, suc_data);
 975         device = suc_data->device;
 976
 977         /* 1. flush alias devices */
 978         flush_all_alias_devices_on_lcu(lcu);
 979
 980         /* 2. reset summary unit check */
 981         spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
 982         dasd_device_remove_stop_bits(device,
 983                                      (DASD_STOPPED_SU | DASD_STOPPED_PENDING));
 984         spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
 985         reset_summary_unit_check(lcu, device, suc_data->reason);
 986
 987         _trylock_and_lock_lcu_irqsave(lcu, NULL, &flags);
 988         _unstop_all_devices_on_lcu(lcu);
 989         _restart_all_base_devices_on_lcu(lcu);
 990         /* 3. read new alias configuration */
 991         _schedule_lcu_update(lcu, device);
 992         lcu->suc_data.device = NULL;
 993         dasd_put_device(device);
 994         _unlock_all_devices_on_lcu(lcu, NULL, NULL);
 995         spin_unlock_irqrestore(&lcu->lock, flags);
 996 }
 997
 998 /*
 999  * note: this will be called from int handler context (cdev locked)
1000  */
1001 void dasd_alias_handle_summary_unit_check(struct dasd_device *device,
1002                                           struct irb *irb)
1003 {
1004         struct dasd_eckd_private *private = device->private;
1005         struct alias_lcu *lcu;
1006         char reason;
1007         char *sense;
1008
1009         sense = dasd_get_sense(irb);
1010         if (sense) {
1011                 reason = sense[8];
1012                 DBF_DEV_EVENT(DBF_NOTICE, device, "%s %x",
1013                             "eckd handle summary unit check: reason", reason);
1014         } else {
1015                 DBF_DEV_EVENT(DBF_WARNING, device, "%s",
1016                             "eckd handle summary unit check:"
1017                             " no reason code available");
1018                 return;
1019         }
1020
1021         lcu = private->lcu;
1022         if (!lcu) {
1023                 DBF_DEV_EVENT(DBF_WARNING, device, "%s",
1024                             "device not ready to handle summary"
1025                             " unit check (no lcu structure)");
1026                 return;
1027         }
1028         _trylock_and_lock_lcu(lcu, device);
1029         /* If this device is about to be removed just return and wait for
1030          * the next interrupt on a different device
1031          */
1032         if (list_empty(&device->alias_list)) {
1033                 DBF_DEV_EVENT(DBF_WARNING, device, "%s",
1034                             "device is in offline processing,"
1035                             " don't do summary unit check handling");
1036                 _unlock_all_devices_on_lcu(lcu, device, NULL);
1037                 spin_unlock(&lcu->lock);
1038                 return;
1039         }
1040         if (lcu->suc_data.device) {
1041                 /* already scheduled or running */
1042                 DBF_DEV_EVENT(DBF_WARNING, device, "%s",
1043                             "previous instance of summary unit check worker"
1044                             " still pending");
1045                 _unlock_all_devices_on_lcu(lcu, device, NULL);
1046                 spin_unlock(&lcu->lock);
1047                 return ;
1048         }
1049         _stop_all_devices_on_lcu(lcu);
1050         /* prepare for lcu_update */
1051         private->lcu->flags |= NEED_UAC_UPDATE | UPDATE_PENDING;
1052         lcu->suc_data.reason = reason;
1053         lcu->suc_data.device = device;
1054         dasd_get_device(device);
1055         _unlock_all_devices_on_lcu(lcu, device, NULL);
1056         spin_unlock(&lcu->lock);
1057         if (!schedule_work(&lcu->suc_data.worker))
1058                 dasd_put_device(device);
1059 };