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         /* make sure that the workers don't use this device */
 259         if (device == lcu->suc_data.device) {
 260                 spin_unlock_irqrestore(&lcu->lock, flags);
 261                 cancel_work_sync(&lcu->suc_data.worker);
 262                 spin_lock_irqsave(&lcu->lock, flags);
 263                 if (device == lcu->suc_data.device) {
 264                         dasd_put_device(device);
 265                         lcu->suc_data.device = NULL;
 266                 }
 267         }
 268         was_pending = 0;
 269         if (device == lcu->ruac_data.device) {
 270                 spin_unlock_irqrestore(&lcu->lock, flags);
 271                 was_pending = 1;
 272                 cancel_delayed_work_sync(&lcu->ruac_data.dwork);
 273                 spin_lock_irqsave(&lcu->lock, flags);
 274                 if (device == lcu->ruac_data.device) {
 275                         dasd_put_device(device);
 276                         lcu->ruac_data.device = NULL;
 277                 }
 278         }
 279         private->lcu = NULL;
 280         spin_unlock_irqrestore(&lcu->lock, flags);
 281
 282         spin_lock_irqsave(&aliastree.lock, flags);
 283         spin_lock(&lcu->lock);
 284         list_del_init(&device->alias_list);
 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         spin_lock(get_ccwdev_lock(device->cdev));
 321         private->uid.type = lcu->uac->unit[private->uid.real_unit_addr].ua_type;
 322         private->uid.base_unit_addr =
 323                 lcu->uac->unit[private->uid.real_unit_addr].base_ua;
 324         uid = private->uid;
 325         spin_unlock(get_ccwdev_lock(device->cdev));
 326         /* if we have no PAV anyway, we don't need to bother with PAV groups */
 327         if (lcu->pav == NO_PAV) {
 328                 list_move(&device->alias_list, &lcu->active_devices);
 329                 return 0;
 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         /*
 386          * intrc values ENODEV, ENOLINK and EPERM
 387          * will be optained from sleep_on to indicate that no
 388          * IO operation can be started
 389          */
 390         if (cqr->intrc == -ENODEV)
 391                 return 1;
 392
 393         if (cqr->intrc == -ENOLINK)
 394                 return 1;
 395
 396         if (cqr->intrc == -EPERM)
 397                 return 1;
 398
 399         sense = dasd_get_sense(&cqr->irb);
 400         if (!sense)
 401                 return 0;
 402
 403         reason = sense[0];
 404         msg_format = (sense[7] & 0xF0);
 405         msg_no = (sense[7] & 0x0F);
 406
 407         /* command reject, Format 0 MSG 4 - invalid parameter */
 408         if ((reason == 0x80) && (msg_format == 0x00) && (msg_no == 0x04))
 409                 return 1;
 410
 411         return 0;
 412 }
 413
 414 static int read_unit_address_configuration(struct dasd_device *device,
 415                                            struct alias_lcu *lcu)
 416 {
 417         struct dasd_psf_prssd_data *prssdp;
 418         struct dasd_ccw_req *cqr;
 419         struct ccw1 *ccw;
 420         int rc;
 421         unsigned long flags;
 422
 423         cqr = dasd_kmalloc_request(DASD_ECKD_MAGIC, 1 /* PSF */ + 1 /* RSSD */,
 424                                    (sizeof(struct dasd_psf_prssd_data)),
 425                                    device);
 426         if (IS_ERR(cqr))
 427                 return PTR_ERR(cqr);
 428         cqr->startdev = device;
 429         cqr->memdev = device;
 430         clear_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags);
 431         cqr->retries = 10;
 432         cqr->expires = 20 * HZ;
 433
 434         /* Prepare for Read Subsystem Data */
 435         prssdp = (struct dasd_psf_prssd_data *) cqr->data;
 436         memset(prssdp, 0, sizeof(struct dasd_psf_prssd_data));
 437         prssdp->order = PSF_ORDER_PRSSD;
 438         prssdp->suborder = 0x0e;        /* Read unit address configuration */
 439         /* all other bytes of prssdp must be zero */
 440
 441         ccw = cqr->cpaddr;
 442         ccw->cmd_code = DASD_ECKD_CCW_PSF;
 443         ccw->count = sizeof(struct dasd_psf_prssd_data);
 444         ccw->flags |= CCW_FLAG_CC;
 445         ccw->cda = (__u32)(addr_t) prssdp;
 446
 447         /* Read Subsystem Data - feature codes */
 448         memset(lcu->uac, 0, sizeof(*(lcu->uac)));
 449
 450         ccw++;
 451         ccw->cmd_code = DASD_ECKD_CCW_RSSD;
 452         ccw->count = sizeof(*(lcu->uac));
 453         ccw->cda = (__u32)(addr_t) lcu->uac;
 454
 455         cqr->buildclk = get_tod_clock();
 456         cqr->status = DASD_CQR_FILLED;
 457
 458         /* need to unset flag here to detect race with summary unit check */
 459         spin_lock_irqsave(&lcu->lock, flags);
 460         lcu->flags &= ~NEED_UAC_UPDATE;
 461         spin_unlock_irqrestore(&lcu->lock, flags);
 462
 463         rc = dasd_sleep_on(cqr);
 464         if (!rc)
 465                 goto out;
 466
 467         if (suborder_not_supported(cqr)) {
 468                 /* suborder not supported or device unusable for IO */
 469                 rc = -EOPNOTSUPP;
 470         } else {
 471                 /* IO failed but should be retried */
 472                 spin_lock_irqsave(&lcu->lock, flags);
 473                 lcu->flags |= NEED_UAC_UPDATE;
 474                 spin_unlock_irqrestore(&lcu->lock, flags);
 475         }
 476 out:
 477         dasd_kfree_request(cqr, cqr->memdev);
 478         return rc;
 479 }
 480
 481 static int _lcu_update(struct dasd_device *refdev, struct alias_lcu *lcu)
 482 {
 483         unsigned long flags;
 484         struct alias_pav_group *pavgroup, *tempgroup;
 485         struct dasd_device *device, *tempdev;
 486         int i, rc;
 487         struct dasd_eckd_private *private;
 488
 489         spin_lock_irqsave(&lcu->lock, flags);
 490         list_for_each_entry_safe(pavgroup, tempgroup, &lcu->grouplist, group) {
 491                 list_for_each_entry_safe(device, tempdev, &pavgroup->baselist,
 492                                          alias_list) {
 493                         list_move(&device->alias_list, &lcu->active_devices);
 494                         private = device->private;
 495                         private->pavgroup = NULL;
 496                 }
 497                 list_for_each_entry_safe(device, tempdev, &pavgroup->aliaslist,
 498                                          alias_list) {
 499                         list_move(&device->alias_list, &lcu->active_devices);
 500                         private = device->private;
 501                         private->pavgroup = NULL;
 502                 }
 503                 list_del(&pavgroup->group);
 504                 kfree(pavgroup);
 505         }
 506         spin_unlock_irqrestore(&lcu->lock, flags);
 507
 508         rc = read_unit_address_configuration(refdev, lcu);
 509         if (rc)
 510                 return rc;
 511
 512         spin_lock_irqsave(&lcu->lock, flags);
 513         /*
 514          * there is another update needed skip the remaining handling
 515          * the data might already be outdated
 516          * but especially do not add the device to an LCU with pending
 517          * update
 518          */
 519         if (lcu->flags & NEED_UAC_UPDATE)
 520                 goto out;
 521         lcu->pav = NO_PAV;
 522         for (i = 0; i < MAX_DEVICES_PER_LCU; ++i) {
 523                 switch (lcu->uac->unit[i].ua_type) {
 524                 case UA_BASE_PAV_ALIAS:
 525                         lcu->pav = BASE_PAV;
 526                         break;
 527                 case UA_HYPER_PAV_ALIAS:
 528                         lcu->pav = HYPER_PAV;
 529                         break;
 530                 }
 531                 if (lcu->pav != NO_PAV)
 532                         break;
 533         }
 534
 535         list_for_each_entry_safe(device, tempdev, &lcu->active_devices,
 536                                  alias_list) {
 537                 _add_device_to_lcu(lcu, device, refdev);
 538         }
 539 out:
 540         spin_unlock_irqrestore(&lcu->lock, flags);
 541         return 0;
 542 }
 543
 544 static void lcu_update_work(struct work_struct *work)
 545 {
 546         struct alias_lcu *lcu;
 547         struct read_uac_work_data *ruac_data;
 548         struct dasd_device *device;
 549         unsigned long flags;
 550         int rc;
 551
 552         ruac_data = container_of(work, struct read_uac_work_data, dwork.work);
 553         lcu = container_of(ruac_data, struct alias_lcu, ruac_data);
 554         device = ruac_data->device;
 555         rc = _lcu_update(device, lcu);
 556         /*
 557          * Need to check flags again, as there could have been another
 558          * prepare_update or a new device a new device while we were still
 559          * processing the data
 560          */
 561         spin_lock_irqsave(&lcu->lock, flags);
 562         if ((rc && (rc != -EOPNOTSUPP)) || (lcu->flags & NEED_UAC_UPDATE)) {
 563                 DBF_DEV_EVENT(DBF_WARNING, device, "could not update"
 564                             " alias data in lcu (rc = %d), retry later", rc);
 565                 if (!schedule_delayed_work(&lcu->ruac_data.dwork, 30*HZ))
 566                         dasd_put_device(device);
 567         } else {
 568                 dasd_put_device(device);
 569                 lcu->ruac_data.device = NULL;
 570                 lcu->flags &= ~UPDATE_PENDING;
 571         }
 572         spin_unlock_irqrestore(&lcu->lock, flags);
 573 }
 574
 575 static int _schedule_lcu_update(struct alias_lcu *lcu,
 576                                 struct dasd_device *device)
 577 {
 578         struct dasd_device *usedev = NULL;
 579         struct alias_pav_group *group;
 580
 581         lcu->flags |= NEED_UAC_UPDATE;
 582         if (lcu->ruac_data.device) {
 583                 /* already scheduled or running */
 584                 return 0;
 585         }
 586         if (device && !list_empty(&device->alias_list))
 587                 usedev = device;
 588
 589         if (!usedev && !list_empty(&lcu->grouplist)) {
 590                 group = list_first_entry(&lcu->grouplist,
 591                                          struct alias_pav_group, group);
 592                 if (!list_empty(&group->baselist))
 593                         usedev = list_first_entry(&group->baselist,
 594                                                   struct dasd_device,
 595                                                   alias_list);
 596                 else if (!list_empty(&group->aliaslist))
 597                         usedev = list_first_entry(&group->aliaslist,
 598                                                   struct dasd_device,
 599                                                   alias_list);
 600         }
 601         if (!usedev && !list_empty(&lcu->active_devices)) {
 602                 usedev = list_first_entry(&lcu->active_devices,
 603                                           struct dasd_device, alias_list);
 604         }
 605         /*
 606          * if we haven't found a proper device yet, give up for now, the next
 607          * device that will be set active will trigger an lcu update
 608          */
 609         if (!usedev)
 610                 return -EINVAL;
 611         dasd_get_device(usedev);
 612         lcu->ruac_data.device = usedev;
 613         if (!schedule_delayed_work(&lcu->ruac_data.dwork, 0))
 614                 dasd_put_device(usedev);
 615         return 0;
 616 }
 617
 618 int dasd_alias_add_device(struct dasd_device *device)
 619 {
 620         struct dasd_eckd_private *private = device->private;
 621         __u8 uaddr = private->uid.real_unit_addr;
 622         struct alias_lcu *lcu = private->lcu;
 623         unsigned long flags;
 624         int rc;
 625
 626         rc = 0;
 627         spin_lock_irqsave(&lcu->lock, flags);
 628         /*
 629          * Check if device and lcu type differ. If so, the uac data may be
 630          * outdated and needs to be updated.
 631          */
 632         if (private->uid.type !=  lcu->uac->unit[uaddr].ua_type) {
 633                 lcu->flags |= UPDATE_PENDING;
 634                 DBF_DEV_EVENT(DBF_WARNING, device, "%s",
 635                               "uid type mismatch - trigger rescan");
 636         }
 637         if (!(lcu->flags & UPDATE_PENDING)) {
 638                 rc = _add_device_to_lcu(lcu, device, device);
 639                 if (rc)
 640                         lcu->flags |= UPDATE_PENDING;
 641         }
 642         if (lcu->flags & UPDATE_PENDING) {
 643                 list_move(&device->alias_list, &lcu->active_devices);
 644                 private->pavgroup = NULL;
 645                 _schedule_lcu_update(lcu, device);
 646         }
 647         spin_unlock_irqrestore(&lcu->lock, flags);
 648         return rc;
 649 }
 650
 651 int dasd_alias_update_add_device(struct dasd_device *device)
 652 {
 653         struct dasd_eckd_private *private = device->private;
 654
 655         private->lcu->flags |= UPDATE_PENDING;
 656         return dasd_alias_add_device(device);
 657 }
 658
 659 int dasd_alias_remove_device(struct dasd_device *device)
 660 {
 661         struct dasd_eckd_private *private = device->private;
 662         struct alias_lcu *lcu = private->lcu;
 663         unsigned long flags;
 664
 665         /* nothing to do if already removed */
 666         if (!lcu)
 667                 return 0;
 668         spin_lock_irqsave(&lcu->lock, flags);
 669         _remove_device_from_lcu(lcu, device);
 670         spin_unlock_irqrestore(&lcu->lock, flags);
 671         return 0;
 672 }
 673
 674 struct dasd_device *dasd_alias_get_start_dev(struct dasd_device *base_device)
 675 {
 676         struct dasd_eckd_private *alias_priv, *private = base_device->private;
 677         struct alias_lcu *lcu = private->lcu;
 678         struct dasd_device *alias_device;
 679         struct alias_pav_group *group;
 680         unsigned long flags;
 681
 682         if (!lcu)
 683                 return NULL;
 684         if (lcu->pav == NO_PAV ||
 685             lcu->flags & (NEED_UAC_UPDATE | UPDATE_PENDING))
 686                 return NULL;
 687         if (unlikely(!(private->features.feature[8] & 0x01))) {
 688                 /*
 689                  * PAV enabled but prefix not, very unlikely
 690                  * seems to be a lost pathgroup
 691                  * use base device to do IO
 692                  */
 693                 DBF_DEV_EVENT(DBF_ERR, base_device, "%s",
 694                               "Prefix not enabled with PAV enabled\n");
 695                 return NULL;
 696         }
 697
 698         spin_lock_irqsave(&lcu->lock, flags);
 699         group = private->pavgroup;
 700         if (!group) {
 701                 spin_unlock_irqrestore(&lcu->lock, flags);
 702                 return NULL;
 703         }
 704         alias_device = group->next;
 705         if (!alias_device) {
 706                 if (list_empty(&group->aliaslist)) {
 707                         spin_unlock_irqrestore(&lcu->lock, flags);
 708                         return NULL;
 709                 } else {
 710                         alias_device = list_first_entry(&group->aliaslist,
 711                                                         struct dasd_device,
 712                                                         alias_list);
 713                 }
 714         }
 715         if (list_is_last(&alias_device->alias_list, &group->aliaslist))
 716                 group->next = list_first_entry(&group->aliaslist,
 717                                                struct dasd_device, alias_list);
 718         else
 719                 group->next = list_first_entry(&alias_device->alias_list,
 720                                                struct dasd_device, alias_list);
 721         spin_unlock_irqrestore(&lcu->lock, flags);
 722         alias_priv = alias_device->private;
 723         if ((alias_priv->count < private->count) && !alias_device->stopped &&
 724             !test_bit(DASD_FLAG_OFFLINE, &alias_device->flags))
 725                 return alias_device;
 726         else
 727                 return NULL;
 728 }
 729
 730 /*
 731  * Summary unit check handling depends on the way alias devices
 732  * are handled so it is done here rather then in dasd_eckd.c
 733  */
 734 static int reset_summary_unit_check(struct alias_lcu *lcu,
 735                                     struct dasd_device *device,
 736                                     char reason)
 737 {
 738         struct dasd_ccw_req *cqr;
 739         int rc = 0;
 740         struct ccw1 *ccw;
 741
 742         cqr = lcu->rsu_cqr;
 743         strncpy((char *) &cqr->magic, "ECKD", 4);
 744         ASCEBC((char *) &cqr->magic, 4);
 745         ccw = cqr->cpaddr;
 746         ccw->cmd_code = DASD_ECKD_CCW_RSCK;
 747         ccw->flags = CCW_FLAG_SLI;
 748         ccw->count = 16;
 749         ccw->cda = (__u32)(addr_t) cqr->data;
 750         ((char *)cqr->data)[0] = reason;
 751
 752         clear_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags);
 753         cqr->retries = 255;     /* set retry counter to enable basic ERP */
 754         cqr->startdev = device;
 755         cqr->memdev = device;
 756         cqr->block = NULL;
 757         cqr->expires = 5 * HZ;
 758         cqr->buildclk = get_tod_clock();
 759         cqr->status = DASD_CQR_FILLED;
 760
 761         rc = dasd_sleep_on_immediatly(cqr);
 762         return rc;
 763 }
 764
 765 static void _restart_all_base_devices_on_lcu(struct alias_lcu *lcu)
 766 {
 767         struct alias_pav_group *pavgroup;
 768         struct dasd_device *device;
 769         struct dasd_eckd_private *private;
 770
 771         /* active and inactive list can contain alias as well as base devices */
 772         list_for_each_entry(device, &lcu->active_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(device, &lcu->inactive_devices, alias_list) {
 780                 private = device->private;
 781                 if (private->uid.type != UA_BASE_DEVICE)
 782                         continue;
 783                 dasd_schedule_block_bh(device->block);
 784                 dasd_schedule_device_bh(device);
 785         }
 786         list_for_each_entry(pavgroup, &lcu->grouplist, group) {
 787                 list_for_each_entry(device, &pavgroup->baselist, alias_list) {
 788                         dasd_schedule_block_bh(device->block);
 789                         dasd_schedule_device_bh(device);
 790                 }
 791         }
 792 }
 793
 794 static void flush_all_alias_devices_on_lcu(struct alias_lcu *lcu)
 795 {
 796         struct alias_pav_group *pavgroup;
 797         struct dasd_device *device, *temp;
 798         struct dasd_eckd_private *private;
 799         int rc;
 800         unsigned long flags;
 801         LIST_HEAD(active);
 802
 803         /*
 804          * Problem here ist that dasd_flush_device_queue may wait
 805          * for termination of a request to complete. We can't keep
 806          * the lcu lock during that time, so we must assume that
 807          * the lists may have changed.
 808          * Idea: first gather all active alias devices in a separate list,
 809          * then flush the first element of this list unlocked, and afterwards
 810          * check if it is still on the list before moving it to the
 811          * active_devices list.
 812          */
 813
 814         spin_lock_irqsave(&lcu->lock, flags);
 815         list_for_each_entry_safe(device, temp, &lcu->active_devices,
 816                                  alias_list) {
 817                 private = device->private;
 818                 if (private->uid.type == UA_BASE_DEVICE)
 819                         continue;
 820                 list_move(&device->alias_list, &active);
 821         }
 822
 823         list_for_each_entry(pavgroup, &lcu->grouplist, group) {
 824                 list_splice_init(&pavgroup->aliaslist, &active);
 825         }
 826         while (!list_empty(&active)) {
 827                 device = list_first_entry(&active, struct dasd_device,
 828                                           alias_list);
 829                 spin_unlock_irqrestore(&lcu->lock, flags);
 830                 rc = dasd_flush_device_queue(device);
 831                 spin_lock_irqsave(&lcu->lock, flags);
 832                 /*
 833                  * only move device around if it wasn't moved away while we
 834                  * were waiting for the flush
 835                  */
 836                 if (device == list_first_entry(&active,
 837                                                struct dasd_device, alias_list)) {
 838                         list_move(&device->alias_list, &lcu->active_devices);
 839                         private = device->private;
 840                         private->pavgroup = NULL;
 841                 }
 842         }
 843         spin_unlock_irqrestore(&lcu->lock, flags);
 844 }
 845
 846 static void _stop_all_devices_on_lcu(struct alias_lcu *lcu)
 847 {
 848         struct alias_pav_group *pavgroup;
 849         struct dasd_device *device;
 850
 851         list_for_each_entry(device, &lcu->active_devices, alias_list) {
 852                 spin_lock(get_ccwdev_lock(device->cdev));
 853                 dasd_device_set_stop_bits(device, DASD_STOPPED_SU);
 854                 spin_unlock(get_ccwdev_lock(device->cdev));
 855         }
 856         list_for_each_entry(device, &lcu->inactive_devices, alias_list) {
 857                 spin_lock(get_ccwdev_lock(device->cdev));
 858                 dasd_device_set_stop_bits(device, DASD_STOPPED_SU);
 859                 spin_unlock(get_ccwdev_lock(device->cdev));
 860         }
 861         list_for_each_entry(pavgroup, &lcu->grouplist, group) {
 862                 list_for_each_entry(device, &pavgroup->baselist, alias_list) {
 863                         spin_lock(get_ccwdev_lock(device->cdev));
 864                         dasd_device_set_stop_bits(device, DASD_STOPPED_SU);
 865                         spin_unlock(get_ccwdev_lock(device->cdev));
 866                 }
 867                 list_for_each_entry(device, &pavgroup->aliaslist, alias_list) {
 868                         spin_lock(get_ccwdev_lock(device->cdev));
 869                         dasd_device_set_stop_bits(device, DASD_STOPPED_SU);
 870                         spin_unlock(get_ccwdev_lock(device->cdev));
 871                 }
 872         }
 873 }
 874
 875 static void _unstop_all_devices_on_lcu(struct alias_lcu *lcu)
 876 {
 877         struct alias_pav_group *pavgroup;
 878         struct dasd_device *device;
 879
 880         list_for_each_entry(device, &lcu->active_devices, alias_list) {
 881                 spin_lock(get_ccwdev_lock(device->cdev));
 882                 dasd_device_remove_stop_bits(device, DASD_STOPPED_SU);
 883                 spin_unlock(get_ccwdev_lock(device->cdev));
 884         }
 885         list_for_each_entry(device, &lcu->inactive_devices, alias_list) {
 886                 spin_lock(get_ccwdev_lock(device->cdev));
 887                 dasd_device_remove_stop_bits(device, DASD_STOPPED_SU);
 888                 spin_unlock(get_ccwdev_lock(device->cdev));
 889         }
 890         list_for_each_entry(pavgroup, &lcu->grouplist, group) {
 891                 list_for_each_entry(device, &pavgroup->baselist, alias_list) {
 892                         spin_lock(get_ccwdev_lock(device->cdev));
 893                         dasd_device_remove_stop_bits(device, DASD_STOPPED_SU);
 894                         spin_unlock(get_ccwdev_lock(device->cdev));
 895                 }
 896                 list_for_each_entry(device, &pavgroup->aliaslist, alias_list) {
 897                         spin_lock(get_ccwdev_lock(device->cdev));
 898                         dasd_device_remove_stop_bits(device, DASD_STOPPED_SU);
 899                         spin_unlock(get_ccwdev_lock(device->cdev));
 900                 }
 901         }
 902 }
 903
 904 static void summary_unit_check_handling_work(struct work_struct *work)
 905 {
 906         struct alias_lcu *lcu;
 907         struct summary_unit_check_work_data *suc_data;
 908         unsigned long flags;
 909         struct dasd_device *device;
 910
 911         suc_data = container_of(work, struct summary_unit_check_work_data,
 912                                 worker);
 913         lcu = container_of(suc_data, struct alias_lcu, suc_data);
 914         device = suc_data->device;
 915
 916         /* 1. flush alias devices */
 917         flush_all_alias_devices_on_lcu(lcu);
 918
 919         /* 2. reset summary unit check */
 920         spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
 921         dasd_device_remove_stop_bits(device,
 922                                      (DASD_STOPPED_SU | DASD_STOPPED_PENDING));
 923         spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
 924         reset_summary_unit_check(lcu, device, suc_data->reason);
 925
 926         spin_lock_irqsave(&lcu->lock, flags);
 927         _unstop_all_devices_on_lcu(lcu);
 928         _restart_all_base_devices_on_lcu(lcu);
 929         /* 3. read new alias configuration */
 930         _schedule_lcu_update(lcu, device);
 931         lcu->suc_data.device = NULL;
 932         dasd_put_device(device);
 933         spin_unlock_irqrestore(&lcu->lock, flags);
 934 }
 935
 936 void dasd_alias_handle_summary_unit_check(struct work_struct *work)
 937 {
 938         struct dasd_device *device = container_of(work, struct dasd_device,
 939                                                   suc_work);
 940         struct dasd_eckd_private *private = device->private;
 941         struct alias_lcu *lcu;
 942         unsigned long flags;
 943
 944         lcu = private->lcu;
 945         if (!lcu) {
 946                 DBF_DEV_EVENT(DBF_WARNING, device, "%s",
 947                             "device not ready to handle summary"
 948                             " unit check (no lcu structure)");
 949                 goto out;
 950         }
 951         spin_lock_irqsave(&lcu->lock, flags);
 952         /* If this device is about to be removed just return and wait for
 953          * the next interrupt on a different device
 954          */
 955         if (list_empty(&device->alias_list)) {
 956                 DBF_DEV_EVENT(DBF_WARNING, device, "%s",
 957                             "device is in offline processing,"
 958                             " don't do summary unit check handling");
 959                 goto out_unlock;
 960         }
 961         if (lcu->suc_data.device) {
 962                 /* already scheduled or running */
 963                 DBF_DEV_EVENT(DBF_WARNING, device, "%s",
 964                             "previous instance of summary unit check worker"
 965                             " still pending");
 966                 goto out_unlock;
 967         }
 968         _stop_all_devices_on_lcu(lcu);
 969         /* prepare for lcu_update */
 970         lcu->flags |= NEED_UAC_UPDATE | UPDATE_PENDING;
 971         lcu->suc_data.reason = private->suc_reason;
 972         lcu->suc_data.device = device;
 973         dasd_get_device(device);
 974         if (!schedule_work(&lcu->suc_data.worker))
 975                 dasd_put_device(device);
 976 out_unlock:
 977         spin_unlock_irqrestore(&lcu->lock, flags);
 978 out:
 979         clear_bit(DASD_FLAG_SUC, &device->flags);
 980         dasd_put_device(device);
 981 };