drivers/s390/block/dasd_alias.c

   1 /*
   2  * PAV alias management for the DASD ECKD discipline
   3  *
   4  * Copyright IBM Corporation, 2007
   5  * Author(s): Stefan Weinhuber <wein@de.ibm.com>
   6  */
   7
   8 #define KMSG_COMPONENT "dasd-eckd"
   9
  10 #include <linux/list.h>
  11 #include <linux/slab.h>
  12 #include <asm/ebcdic.h>
  13 #include "dasd_int.h"
  14 #include "dasd_eckd.h"
  15
  16 #ifdef PRINTK_HEADER
  17 #undef PRINTK_HEADER
  18 #endif                          /* PRINTK_HEADER */
  19 #define PRINTK_HEADER "dasd(eckd):"
  20
  21
  22 /*
  23  * General concept of alias management:
  24  * - PAV and DASD alias management is specific to the eckd discipline.
  25  * - A device is connected to an lcu as long as the device exists.
  26  *   dasd_alias_make_device_known_to_lcu will be called wenn the
  27  *   device is checked by the eckd discipline and
  28  *   dasd_alias_disconnect_device_from_lcu will be called
  29  *   before the device is deleted.
  30  * - The dasd_alias_add_device / dasd_alias_remove_device
  31  *   functions mark the point when a device is 'ready for service'.
  32  * - A summary unit check is a rare occasion, but it is mandatory to
  33  *   support it. It requires some complex recovery actions before the
  34  *   devices can be used again (see dasd_alias_handle_summary_unit_check).
  35  * - dasd_alias_get_start_dev will find an alias device that can be used
  36  *   instead of the base device and does some (very simple) load balancing.
  37  *   This is the function that gets called for each I/O, so when improving
  38  *   something, this function should get faster or better, the rest has just
  39  *   to be correct.
  40  */
  41
  42
  43 static void summary_unit_check_handling_work(struct work_struct *);
  44 static void lcu_update_work(struct work_struct *);
  45 static int _schedule_lcu_update(struct alias_lcu *, struct dasd_device *);
  46
  47 static struct alias_root aliastree = {
  48         .serverlist = LIST_HEAD_INIT(aliastree.serverlist),
  49         .lock = __SPIN_LOCK_UNLOCKED(aliastree.lock),
  50 };
  51
  52 static struct alias_server *_find_server(struct dasd_uid *uid)
  53 {
  54         struct alias_server *pos;
  55         list_for_each_entry(pos, &aliastree.serverlist, server) {
  56                 if (!strncmp(pos->uid.vendor, uid->vendor,
  57                              sizeof(uid->vendor))
  58                     && !strncmp(pos->uid.serial, uid->serial,
  59                                 sizeof(uid->serial)))
  60                         return pos;
  61         };
  62         return NULL;
  63 }
  64
  65 static struct alias_lcu *_find_lcu(struct alias_server *server,
  66                                    struct dasd_uid *uid)
  67 {
  68         struct alias_lcu *pos;
  69         list_for_each_entry(pos, &server->lculist, lcu) {
  70                 if (pos->uid.ssid == uid->ssid)
  71                         return pos;
  72         };
  73         return NULL;
  74 }
  75
  76 static struct alias_pav_group *_find_group(struct alias_lcu *lcu,
  77                                            struct dasd_uid *uid)
  78 {
  79         struct alias_pav_group *pos;
  80         __u8 search_unit_addr;
  81
  82         /* for hyper pav there is only one group */
  83         if (lcu->pav == HYPER_PAV) {
  84                 if (list_empty(&lcu->grouplist))
  85                         return NULL;
  86                 else
  87                         return list_first_entry(&lcu->grouplist,
  88                                                 struct alias_pav_group, group);
  89         }
  90
  91         /* for base pav we have to find the group that matches the base */
  92         if (uid->type == UA_BASE_DEVICE)
  93                 search_unit_addr = uid->real_unit_addr;
  94         else
  95                 search_unit_addr = uid->base_unit_addr;
  96         list_for_each_entry(pos, &lcu->grouplist, group) {
  97                 if (pos->uid.base_unit_addr == search_unit_addr &&
  98                     !strncmp(pos->uid.vduit, uid->vduit, sizeof(uid->vduit)))
  99                         return pos;
 100         };
 101         return NULL;
 102 }
 103
 104 static struct alias_server *_allocate_server(struct dasd_uid *uid)
 105 {
 106         struct alias_server *server;
 107
 108         server = kzalloc(sizeof(*server), GFP_KERNEL);
 109         if (!server)
 110                 return ERR_PTR(-ENOMEM);
 111         memcpy(server->uid.vendor, uid->vendor, sizeof(uid->vendor));
 112         memcpy(server->uid.serial, uid->serial, sizeof(uid->serial));
 113         INIT_LIST_HEAD(&server->server);
 114         INIT_LIST_HEAD(&server->lculist);
 115         return server;
 116 }
 117
 118 static void _free_server(struct alias_server *server)
 119 {
 120         kfree(server);
 121 }
 122
 123 static struct alias_lcu *_allocate_lcu(struct dasd_uid *uid)
 124 {
 125         struct alias_lcu *lcu;
 126
 127         lcu = kzalloc(sizeof(*lcu), GFP_KERNEL);
 128         if (!lcu)
 129                 return ERR_PTR(-ENOMEM);
 130         lcu->uac = kzalloc(sizeof(*(lcu->uac)), GFP_KERNEL | GFP_DMA);
 131         if (!lcu->uac)
 132                 goto out_err1;
 133         lcu->rsu_cqr = kzalloc(sizeof(*lcu->rsu_cqr), GFP_KERNEL | GFP_DMA);
 134         if (!lcu->rsu_cqr)
 135                 goto out_err2;
 136         lcu->rsu_cqr->cpaddr = kzalloc(sizeof(struct ccw1),
 137                                        GFP_KERNEL | GFP_DMA);
 138         if (!lcu->rsu_cqr->cpaddr)
 139                 goto out_err3;
 140         lcu->rsu_cqr->data = kzalloc(16, GFP_KERNEL | GFP_DMA);
 141         if (!lcu->rsu_cqr->data)
 142                 goto out_err4;
 143
 144         memcpy(lcu->uid.vendor, uid->vendor, sizeof(uid->vendor));
 145         memcpy(lcu->uid.serial, uid->serial, sizeof(uid->serial));
 146         lcu->uid.ssid = uid->ssid;
 147         lcu->pav = NO_PAV;
 148         lcu->flags = NEED_UAC_UPDATE | UPDATE_PENDING;
 149         INIT_LIST_HEAD(&lcu->lcu);
 150         INIT_LIST_HEAD(&lcu->inactive_devices);
 151         INIT_LIST_HEAD(&lcu->active_devices);
 152         INIT_LIST_HEAD(&lcu->grouplist);
 153         INIT_WORK(&lcu->suc_data.worker, summary_unit_check_handling_work);
 154         INIT_DELAYED_WORK(&lcu->ruac_data.dwork, lcu_update_work);
 155         spin_lock_init(&lcu->lock);
 156         init_completion(&lcu->lcu_setup);
 157         return lcu;
 158
 159 out_err4:
 160         kfree(lcu->rsu_cqr->cpaddr);
 161 out_err3:
 162         kfree(lcu->rsu_cqr);
 163 out_err2:
 164         kfree(lcu->uac);
 165 out_err1:
 166         kfree(lcu);
 167         return ERR_PTR(-ENOMEM);
 168 }
 169
 170 static void _free_lcu(struct alias_lcu *lcu)
 171 {
 172         kfree(lcu->rsu_cqr->data);
 173         kfree(lcu->rsu_cqr->cpaddr);
 174         kfree(lcu->rsu_cqr);
 175         kfree(lcu->uac);
 176         kfree(lcu);
 177 }
 178
 179 /*
 180  * This is the function that will allocate all the server and lcu data,
 181  * so this function must be called first for a new device.
 182  * If the return value is 1, the lcu was already known before, if it
 183  * is 0, this is a new lcu.
 184  * Negative return code indicates that something went wrong (e.g. -ENOMEM)
 185  */
 186 int dasd_alias_make_device_known_to_lcu(struct dasd_device *device)
 187 {
 188         struct dasd_eckd_private *private;
 189         unsigned long flags;
 190         struct alias_server *server, *newserver;
 191         struct alias_lcu *lcu, *newlcu;
 192         int is_lcu_known;
 193         struct dasd_uid uid;
 194
 195         private = (struct dasd_eckd_private *) device->private;
 196
 197         device->discipline->get_uid(device, &uid);
 198         spin_lock_irqsave(&aliastree.lock, flags);
 199         is_lcu_known = 1;
 200         server = _find_server(&uid);
 201         if (!server) {
 202                 spin_unlock_irqrestore(&aliastree.lock, flags);
 203                 newserver = _allocate_server(&uid);
 204                 if (IS_ERR(newserver))
 205                         return PTR_ERR(newserver);
 206                 spin_lock_irqsave(&aliastree.lock, flags);
 207                 server = _find_server(&uid);
 208                 if (!server) {
 209                         list_add(&newserver->server, &aliastree.serverlist);
 210                         server = newserver;
 211                         is_lcu_known = 0;
 212                 } else {
 213                         /* someone was faster */
 214                         _free_server(newserver);
 215                 }
 216         }
 217
 218         lcu = _find_lcu(server, &uid);
 219         if (!lcu) {
 220                 spin_unlock_irqrestore(&aliastree.lock, flags);
 221                 newlcu = _allocate_lcu(&uid);
 222                 if (IS_ERR(newlcu))
 223                         return PTR_ERR(newlcu);
 224                 spin_lock_irqsave(&aliastree.lock, flags);
 225                 lcu = _find_lcu(server, &uid);
 226                 if (!lcu) {
 227                         list_add(&newlcu->lcu, &server->lculist);
 228                         lcu = newlcu;
 229                         is_lcu_known = 0;
 230                 } else {
 231                         /* someone was faster */
 232                         _free_lcu(newlcu);
 233                 }
 234                 is_lcu_known = 0;
 235         }
 236         spin_lock(&lcu->lock);
 237         list_add(&device->alias_list, &lcu->inactive_devices);
 238         private->lcu = lcu;
 239         spin_unlock(&lcu->lock);
 240         spin_unlock_irqrestore(&aliastree.lock, flags);
 241
 242         return is_lcu_known;
 243 }
 244
 245 /*
 246  * The first device to be registered on an LCU will have to do
 247  * some additional setup steps to configure that LCU on the
 248  * storage server. All further devices should wait with their
 249  * initialization until the first device is done.
 250  * To synchronize this work, the first device will call
 251  * dasd_alias_lcu_setup_complete when it is done, and all
 252  * other devices will wait for it with dasd_alias_wait_for_lcu_setup.
 253  */
 254 void dasd_alias_lcu_setup_complete(struct dasd_device *device)
 255 {
 256         unsigned long flags;
 257         struct alias_server *server;
 258         struct alias_lcu *lcu;
 259         struct dasd_uid uid;
 260
 261         device->discipline->get_uid(device, &uid);
 262         lcu = NULL;
 263         spin_lock_irqsave(&aliastree.lock, flags);
 264         server = _find_server(&uid);
 265         if (server)
 266                 lcu = _find_lcu(server, &uid);
 267         spin_unlock_irqrestore(&aliastree.lock, flags);
 268         if (!lcu) {
 269                 DBF_EVENT_DEVID(DBF_ERR, device->cdev,
 270                                 "could not find lcu for %04x %02x",
 271                                 uid.ssid, uid.real_unit_addr);
 272                 WARN_ON(1);
 273                 return;
 274         }
 275         complete_all(&lcu->lcu_setup);
 276 }
 277
 278 void dasd_alias_wait_for_lcu_setup(struct dasd_device *device)
 279 {
 280         unsigned long flags;
 281         struct alias_server *server;
 282         struct alias_lcu *lcu;
 283         struct dasd_uid uid;
 284
 285         device->discipline->get_uid(device, &uid);
 286         lcu = NULL;
 287         spin_lock_irqsave(&aliastree.lock, flags);
 288         server = _find_server(&uid);
 289         if (server)
 290                 lcu = _find_lcu(server, &uid);
 291         spin_unlock_irqrestore(&aliastree.lock, flags);
 292         if (!lcu) {
 293                 DBF_EVENT_DEVID(DBF_ERR, device->cdev,
 294                                 "could not find lcu for %04x %02x",
 295                                 uid.ssid, uid.real_unit_addr);
 296                 WARN_ON(1);
 297                 return;
 298         }
 299         wait_for_completion(&lcu->lcu_setup);
 300 }
 301
 302 /*
 303  * This function removes a device from the scope of alias management.
 304  * The complicated part is to make sure that it is not in use by
 305  * any of the workers. If necessary cancel the work.
 306  */
 307 void dasd_alias_disconnect_device_from_lcu(struct dasd_device *device)
 308 {
 309         struct dasd_eckd_private *private;
 310         unsigned long flags;
 311         struct alias_lcu *lcu;
 312         struct alias_server *server;
 313         int was_pending;
 314         struct dasd_uid uid;
 315
 316         private = (struct dasd_eckd_private *) device->private;
 317         lcu = private->lcu;
 318         /* nothing to do if already disconnected */
 319         if (!lcu)
 320                 return;
 321         device->discipline->get_uid(device, &uid);
 322         spin_lock_irqsave(&lcu->lock, flags);
 323         list_del_init(&device->alias_list);
 324         /* make sure that the workers don't use this device */
 325         if (device == lcu->suc_data.device) {
 326                 spin_unlock_irqrestore(&lcu->lock, flags);
 327                 cancel_work_sync(&lcu->suc_data.worker);
 328                 spin_lock_irqsave(&lcu->lock, flags);
 329                 if (device == lcu->suc_data.device)
 330                         lcu->suc_data.device = NULL;
 331         }
 332         was_pending = 0;
 333         if (device == lcu->ruac_data.device) {
 334                 spin_unlock_irqrestore(&lcu->lock, flags);
 335                 was_pending = 1;
 336                 cancel_delayed_work_sync(&lcu->ruac_data.dwork);
 337                 spin_lock_irqsave(&lcu->lock, flags);
 338                 if (device == lcu->ruac_data.device)
 339                         lcu->ruac_data.device = NULL;
 340         }
 341         private->lcu = NULL;
 342         spin_unlock_irqrestore(&lcu->lock, flags);
 343
 344         spin_lock_irqsave(&aliastree.lock, flags);
 345         spin_lock(&lcu->lock);
 346         if (list_empty(&lcu->grouplist) &&
 347             list_empty(&lcu->active_devices) &&
 348             list_empty(&lcu->inactive_devices)) {
 349                 list_del(&lcu->lcu);
 350                 spin_unlock(&lcu->lock);
 351                 _free_lcu(lcu);
 352                 lcu = NULL;
 353         } else {
 354                 if (was_pending)
 355                         _schedule_lcu_update(lcu, NULL);
 356                 spin_unlock(&lcu->lock);
 357         }
 358         server = _find_server(&uid);
 359         if (server && list_empty(&server->lculist)) {
 360                 list_del(&server->server);
 361                 _free_server(server);
 362         }
 363         spin_unlock_irqrestore(&aliastree.lock, flags);
 364 }
 365
 366 /*
 367  * This function assumes that the unit address configuration stored
 368  * in the lcu is up to date and will update the device uid before
 369  * adding it to a pav group.
 370  */
 371
 372 static int _add_device_to_lcu(struct alias_lcu *lcu,
 373                               struct dasd_device *device,
 374                               struct dasd_device *pos)
 375 {
 376
 377         struct dasd_eckd_private *private;
 378         struct alias_pav_group *group;
 379         struct dasd_uid uid;
 380         unsigned long flags;
 381
 382         private = (struct dasd_eckd_private *) device->private;
 383
 384         /* only lock if not already locked */
 385         if (device != pos)
 386                 spin_lock_irqsave_nested(get_ccwdev_lock(device->cdev), flags,
 387                                          CDEV_NESTED_SECOND);
 388         private->uid.type = lcu->uac->unit[private->uid.real_unit_addr].ua_type;
 389         private->uid.base_unit_addr =
 390                 lcu->uac->unit[private->uid.real_unit_addr].base_ua;
 391         uid = private->uid;
 392
 393         if (device != pos)
 394                 spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
 395
 396         /* if we have no PAV anyway, we don't need to bother with PAV groups */
 397         if (lcu->pav == NO_PAV) {
 398                 list_move(&device->alias_list, &lcu->active_devices);
 399                 return 0;
 400         }
 401
 402         group = _find_group(lcu, &uid);
 403         if (!group) {
 404                 group = kzalloc(sizeof(*group), GFP_ATOMIC);
 405                 if (!group)
 406                         return -ENOMEM;
 407                 memcpy(group->uid.vendor, uid.vendor, sizeof(uid.vendor));
 408                 memcpy(group->uid.serial, uid.serial, sizeof(uid.serial));
 409                 group->uid.ssid = uid.ssid;
 410                 if (uid.type == UA_BASE_DEVICE)
 411                         group->uid.base_unit_addr = uid.real_unit_addr;
 412                 else
 413                         group->uid.base_unit_addr = uid.base_unit_addr;
 414                 memcpy(group->uid.vduit, uid.vduit, sizeof(uid.vduit));
 415                 INIT_LIST_HEAD(&group->group);
 416                 INIT_LIST_HEAD(&group->baselist);
 417                 INIT_LIST_HEAD(&group->aliaslist);
 418                 list_add(&group->group, &lcu->grouplist);
 419         }
 420         if (uid.type == UA_BASE_DEVICE)
 421                 list_move(&device->alias_list, &group->baselist);
 422         else
 423                 list_move(&device->alias_list, &group->aliaslist);
 424         private->pavgroup = group;
 425         return 0;
 426 };
 427
 428 static void _remove_device_from_lcu(struct alias_lcu *lcu,
 429                                     struct dasd_device *device)
 430 {
 431         struct dasd_eckd_private *private;
 432         struct alias_pav_group *group;
 433
 434         private = (struct dasd_eckd_private *) device->private;
 435         list_move(&device->alias_list, &lcu->inactive_devices);
 436         group = private->pavgroup;
 437         if (!group)
 438                 return;
 439         private->pavgroup = NULL;
 440         if (list_empty(&group->baselist) && list_empty(&group->aliaslist)) {
 441                 list_del(&group->group);
 442                 kfree(group);
 443                 return;
 444         }
 445         if (group->next == device)
 446                 group->next = NULL;
 447 };
 448
 449 static int read_unit_address_configuration(struct dasd_device *device,
 450                                            struct alias_lcu *lcu)
 451 {
 452         struct dasd_psf_prssd_data *prssdp;
 453         struct dasd_ccw_req *cqr;
 454         struct ccw1 *ccw;
 455         int rc;
 456         unsigned long flags;
 457
 458         cqr = dasd_kmalloc_request(DASD_ECKD_MAGIC, 1 /* PSF */ + 1 /* RSSD */,
 459                                    (sizeof(struct dasd_psf_prssd_data)),
 460                                    device);
 461         if (IS_ERR(cqr))
 462                 return PTR_ERR(cqr);
 463         cqr->startdev = device;
 464         cqr->memdev = device;
 465         clear_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags);
 466         cqr->retries = 10;
 467         cqr->expires = 20 * HZ;
 468
 469         /* Prepare for Read Subsystem Data */
 470         prssdp = (struct dasd_psf_prssd_data *) cqr->data;
 471         memset(prssdp, 0, sizeof(struct dasd_psf_prssd_data));
 472         prssdp->order = PSF_ORDER_PRSSD;
 473         prssdp->suborder = 0x0e;        /* Read unit address configuration */
 474         /* all other bytes of prssdp must be zero */
 475
 476         ccw = cqr->cpaddr;
 477         ccw->cmd_code = DASD_ECKD_CCW_PSF;
 478         ccw->count = sizeof(struct dasd_psf_prssd_data);
 479         ccw->flags |= CCW_FLAG_CC;
 480         ccw->cda = (__u32)(addr_t) prssdp;
 481
 482         /* Read Subsystem Data - feature codes */
 483         memset(lcu->uac, 0, sizeof(*(lcu->uac)));
 484
 485         ccw++;
 486         ccw->cmd_code = DASD_ECKD_CCW_RSSD;
 487         ccw->count = sizeof(*(lcu->uac));
 488         ccw->cda = (__u32)(addr_t) lcu->uac;
 489
 490         cqr->buildclk = get_clock();
 491         cqr->status = DASD_CQR_FILLED;
 492
 493         /* need to unset flag here to detect race with summary unit check */
 494         spin_lock_irqsave(&lcu->lock, flags);
 495         lcu->flags &= ~NEED_UAC_UPDATE;
 496         spin_unlock_irqrestore(&lcu->lock, flags);
 497
 498         do {
 499                 rc = dasd_sleep_on(cqr);
 500         } while (rc && (cqr->retries > 0));
 501         if (rc) {
 502                 spin_lock_irqsave(&lcu->lock, flags);
 503                 lcu->flags |= NEED_UAC_UPDATE;
 504                 spin_unlock_irqrestore(&lcu->lock, flags);
 505         }
 506         dasd_kfree_request(cqr, cqr->memdev);
 507         return rc;
 508 }
 509
 510 static int _lcu_update(struct dasd_device *refdev, struct alias_lcu *lcu)
 511 {
 512         unsigned long flags;
 513         struct alias_pav_group *pavgroup, *tempgroup;
 514         struct dasd_device *device, *tempdev;
 515         int i, rc;
 516         struct dasd_eckd_private *private;
 517
 518         spin_lock_irqsave(&lcu->lock, flags);
 519         list_for_each_entry_safe(pavgroup, tempgroup, &lcu->grouplist, group) {
 520                 list_for_each_entry_safe(device, tempdev, &pavgroup->baselist,
 521                                          alias_list) {
 522                         list_move(&device->alias_list, &lcu->active_devices);
 523                         private = (struct dasd_eckd_private *) device->private;
 524                         private->pavgroup = NULL;
 525                 }
 526                 list_for_each_entry_safe(device, tempdev, &pavgroup->aliaslist,
 527                                          alias_list) {
 528                         list_move(&device->alias_list, &lcu->active_devices);
 529                         private = (struct dasd_eckd_private *) device->private;
 530                         private->pavgroup = NULL;
 531                 }
 532                 list_del(&pavgroup->group);
 533                 kfree(pavgroup);
 534         }
 535         spin_unlock_irqrestore(&lcu->lock, flags);
 536
 537         rc = read_unit_address_configuration(refdev, lcu);
 538         if (rc)
 539                 return rc;
 540
 541         /* need to take cdev lock before lcu lock */
 542         spin_lock_irqsave_nested(get_ccwdev_lock(refdev->cdev), flags,
 543                                  CDEV_NESTED_FIRST);
 544         spin_lock(&lcu->lock);
 545         lcu->pav = NO_PAV;
 546         for (i = 0; i < MAX_DEVICES_PER_LCU; ++i) {
 547                 switch (lcu->uac->unit[i].ua_type) {
 548                 case UA_BASE_PAV_ALIAS:
 549                         lcu->pav = BASE_PAV;
 550                         break;
 551                 case UA_HYPER_PAV_ALIAS:
 552                         lcu->pav = HYPER_PAV;
 553                         break;
 554                 }
 555                 if (lcu->pav != NO_PAV)
 556                         break;
 557         }
 558
 559         list_for_each_entry_safe(device, tempdev, &lcu->active_devices,
 560                                  alias_list) {
 561                 _add_device_to_lcu(lcu, device, refdev);
 562         }
 563         spin_unlock(&lcu->lock);
 564         spin_unlock_irqrestore(get_ccwdev_lock(refdev->cdev), flags);
 565         return 0;
 566 }
 567
 568 static void lcu_update_work(struct work_struct *work)
 569 {
 570         struct alias_lcu *lcu;
 571         struct read_uac_work_data *ruac_data;
 572         struct dasd_device *device;
 573         unsigned long flags;
 574         int rc;
 575
 576         ruac_data = container_of(work, struct read_uac_work_data, dwork.work);
 577         lcu = container_of(ruac_data, struct alias_lcu, ruac_data);
 578         device = ruac_data->device;
 579         rc = _lcu_update(device, lcu);
 580         /*
 581          * Need to check flags again, as there could have been another
 582          * prepare_update or a new device a new device while we were still
 583          * processing the data
 584          */
 585         spin_lock_irqsave(&lcu->lock, flags);
 586         if (rc || (lcu->flags & NEED_UAC_UPDATE)) {
 587                 DBF_DEV_EVENT(DBF_WARNING, device, "could not update"
 588                             " alias data in lcu (rc = %d), retry later", rc);
 589                 schedule_delayed_work(&lcu->ruac_data.dwork, 30*HZ);
 590         } else {
 591                 lcu->ruac_data.device = NULL;
 592                 lcu->flags &= ~UPDATE_PENDING;
 593         }
 594         spin_unlock_irqrestore(&lcu->lock, flags);
 595 }
 596
 597 static int _schedule_lcu_update(struct alias_lcu *lcu,
 598                                 struct dasd_device *device)
 599 {
 600         struct dasd_device *usedev = NULL;
 601         struct alias_pav_group *group;
 602
 603         lcu->flags |= NEED_UAC_UPDATE;
 604         if (lcu->ruac_data.device) {
 605                 /* already scheduled or running */
 606                 return 0;
 607         }
 608         if (device && !list_empty(&device->alias_list))
 609                 usedev = device;
 610
 611         if (!usedev && !list_empty(&lcu->grouplist)) {
 612                 group = list_first_entry(&lcu->grouplist,
 613                                          struct alias_pav_group, group);
 614                 if (!list_empty(&group->baselist))
 615                         usedev = list_first_entry(&group->baselist,
 616                                                   struct dasd_device,
 617                                                   alias_list);
 618                 else if (!list_empty(&group->aliaslist))
 619                         usedev = list_first_entry(&group->aliaslist,
 620                                                   struct dasd_device,
 621                                                   alias_list);
 622         }
 623         if (!usedev && !list_empty(&lcu->active_devices)) {
 624                 usedev = list_first_entry(&lcu->active_devices,
 625                                           struct dasd_device, alias_list);
 626         }
 627         /*
 628          * if we haven't found a proper device yet, give up for now, the next
 629          * device that will be set active will trigger an lcu update
 630          */
 631         if (!usedev)
 632                 return -EINVAL;
 633         lcu->ruac_data.device = usedev;
 634         schedule_delayed_work(&lcu->ruac_data.dwork, 0);
 635         return 0;
 636 }
 637
 638 int dasd_alias_add_device(struct dasd_device *device)
 639 {
 640         struct dasd_eckd_private *private;
 641         struct alias_lcu *lcu;
 642         unsigned long flags;
 643         int rc;
 644
 645         private = (struct dasd_eckd_private *) device->private;
 646         lcu = private->lcu;
 647         rc = 0;
 648
 649         /* need to take cdev lock before lcu lock */
 650         spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
 651         spin_lock(&lcu->lock);
 652         if (!(lcu->flags & UPDATE_PENDING)) {
 653                 rc = _add_device_to_lcu(lcu, device, device);
 654                 if (rc)
 655                         lcu->flags |= UPDATE_PENDING;
 656         }
 657         if (lcu->flags & UPDATE_PENDING) {
 658                 list_move(&device->alias_list, &lcu->active_devices);
 659                 _schedule_lcu_update(lcu, device);
 660         }
 661         spin_unlock(&lcu->lock);
 662         spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
 663         return rc;
 664 }
 665
 666 int dasd_alias_update_add_device(struct dasd_device *device)
 667 {
 668         struct dasd_eckd_private *private;
 669         private = (struct dasd_eckd_private *) device->private;
 670         private->lcu->flags |= UPDATE_PENDING;
 671         return dasd_alias_add_device(device);
 672 }
 673
 674 int dasd_alias_remove_device(struct dasd_device *device)
 675 {
 676         struct dasd_eckd_private *private;
 677         struct alias_lcu *lcu;
 678         unsigned long flags;
 679
 680         private = (struct dasd_eckd_private *) device->private;
 681         lcu = private->lcu;
 682         /* nothing to do if already removed */
 683         if (!lcu)
 684                 return 0;
 685         spin_lock_irqsave(&lcu->lock, flags);
 686         _remove_device_from_lcu(lcu, device);
 687         spin_unlock_irqrestore(&lcu->lock, flags);
 688         return 0;
 689 }
 690
 691 struct dasd_device *dasd_alias_get_start_dev(struct dasd_device *base_device)
 692 {
 693
 694         struct dasd_device *alias_device;
 695         struct alias_pav_group *group;
 696         struct alias_lcu *lcu;
 697         struct dasd_eckd_private *private, *alias_priv;
 698         unsigned long flags;
 699
 700         private = (struct dasd_eckd_private *) base_device->private;
 701         group = private->pavgroup;
 702         lcu = private->lcu;
 703         if (!group || !lcu)
 704                 return NULL;
 705         if (lcu->pav == NO_PAV ||
 706             lcu->flags & (NEED_UAC_UPDATE | UPDATE_PENDING))
 707                 return NULL;
 708         if (unlikely(!(private->features.feature[8] & 0x01))) {
 709                 /*
 710                  * PAV enabled but prefix not, very unlikely
 711                  * seems to be a lost pathgroup
 712                  * use base device to do IO
 713                  */
 714                 DBF_DEV_EVENT(DBF_ERR, base_device, "%s",
 715                               "Prefix not enabled with PAV enabled\n");
 716                 return NULL;
 717         }
 718
 719         spin_lock_irqsave(&lcu->lock, flags);
 720         alias_device = group->next;
 721         if (!alias_device) {
 722                 if (list_empty(&group->aliaslist)) {
 723                         spin_unlock_irqrestore(&lcu->lock, flags);
 724                         return NULL;
 725                 } else {
 726                         alias_device = list_first_entry(&group->aliaslist,
 727                                                         struct dasd_device,
 728                                                         alias_list);
 729                 }
 730         }
 731         if (list_is_last(&alias_device->alias_list, &group->aliaslist))
 732                 group->next = list_first_entry(&group->aliaslist,
 733                                                struct dasd_device, alias_list);
 734         else
 735                 group->next = list_first_entry(&alias_device->alias_list,
 736                                                struct dasd_device, alias_list);
 737         spin_unlock_irqrestore(&lcu->lock, flags);
 738         alias_priv = (struct dasd_eckd_private *) alias_device->private;
 739         if ((alias_priv->count < private->count) && !alias_device->stopped)
 740                 return alias_device;
 741         else
 742                 return NULL;
 743 }
 744
 745 /*
 746  * Summary unit check handling depends on the way alias devices
 747  * are handled so it is done here rather then in dasd_eckd.c
 748  */
 749 static int reset_summary_unit_check(struct alias_lcu *lcu,
 750                                     struct dasd_device *device,
 751                                     char reason)
 752 {
 753         struct dasd_ccw_req *cqr;
 754         int rc = 0;
 755         struct ccw1 *ccw;
 756
 757         cqr = lcu->rsu_cqr;
 758         strncpy((char *) &cqr->magic, "ECKD", 4);
 759         ASCEBC((char *) &cqr->magic, 4);
 760         ccw = cqr->cpaddr;
 761         ccw->cmd_code = DASD_ECKD_CCW_RSCK;
 762         ccw->flags = 0 ;
 763         ccw->count = 16;
 764         ccw->cda = (__u32)(addr_t) cqr->data;
 765         ((char *)cqr->data)[0] = reason;
 766
 767         clear_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags);
 768         cqr->retries = 255;     /* set retry counter to enable basic ERP */
 769         cqr->startdev = device;
 770         cqr->memdev = device;
 771         cqr->block = NULL;
 772         cqr->expires = 5 * HZ;
 773         cqr->buildclk = get_clock();
 774         cqr->status = DASD_CQR_FILLED;
 775
 776         rc = dasd_sleep_on_immediatly(cqr);
 777         return rc;
 778 }
 779
 780 static void _restart_all_base_devices_on_lcu(struct alias_lcu *lcu)
 781 {
 782         struct alias_pav_group *pavgroup;
 783         struct dasd_device *device;
 784         struct dasd_eckd_private *private;
 785         unsigned long flags;
 786
 787         /* active and inactive list can contain alias as well as base devices */
 788         list_for_each_entry(device, &lcu->active_devices, alias_list) {
 789                 private = (struct dasd_eckd_private *) device->private;
 790                 spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
 791                 if (private->uid.type != UA_BASE_DEVICE) {
 792                         spin_unlock_irqrestore(get_ccwdev_lock(device->cdev),
 793                                                flags);
 794                         continue;
 795                 }
 796                 spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
 797                 dasd_schedule_block_bh(device->block);
 798                 dasd_schedule_device_bh(device);
 799         }
 800         list_for_each_entry(device, &lcu->inactive_devices, alias_list) {
 801                 private = (struct dasd_eckd_private *) device->private;
 802                 spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
 803                 if (private->uid.type != UA_BASE_DEVICE) {
 804                         spin_unlock_irqrestore(get_ccwdev_lock(device->cdev),
 805                                                flags);
 806                         continue;
 807                 }
 808                 spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
 809                 dasd_schedule_block_bh(device->block);
 810                 dasd_schedule_device_bh(device);
 811         }
 812         list_for_each_entry(pavgroup, &lcu->grouplist, group) {
 813                 list_for_each_entry(device, &pavgroup->baselist, alias_list) {
 814                         dasd_schedule_block_bh(device->block);
 815                         dasd_schedule_device_bh(device);
 816                 }
 817         }
 818 }
 819
 820 static void flush_all_alias_devices_on_lcu(struct alias_lcu *lcu)
 821 {
 822         struct alias_pav_group *pavgroup;
 823         struct dasd_device *device, *temp;
 824         struct dasd_eckd_private *private;
 825         int rc;
 826         unsigned long flags;
 827         LIST_HEAD(active);
 828
 829         /*
 830          * Problem here ist that dasd_flush_device_queue may wait
 831          * for termination of a request to complete. We can't keep
 832          * the lcu lock during that time, so we must assume that
 833          * the lists may have changed.
 834          * Idea: first gather all active alias devices in a separate list,
 835          * then flush the first element of this list unlocked, and afterwards
 836          * check if it is still on the list before moving it to the
 837          * active_devices list.
 838          */
 839
 840         spin_lock_irqsave(&lcu->lock, flags);
 841         list_for_each_entry_safe(device, temp, &lcu->active_devices,
 842                                  alias_list) {
 843                 private = (struct dasd_eckd_private *) device->private;
 844                 if (private->uid.type == UA_BASE_DEVICE)
 845                         continue;
 846                 list_move(&device->alias_list, &active);
 847         }
 848
 849         list_for_each_entry(pavgroup, &lcu->grouplist, group) {
 850                 list_splice_init(&pavgroup->aliaslist, &active);
 851         }
 852         while (!list_empty(&active)) {
 853                 device = list_first_entry(&active, struct dasd_device,
 854                                           alias_list);
 855                 spin_unlock_irqrestore(&lcu->lock, flags);
 856                 rc = dasd_flush_device_queue(device);
 857                 spin_lock_irqsave(&lcu->lock, flags);
 858                 /*
 859                  * only move device around if it wasn't moved away while we
 860                  * were waiting for the flush
 861                  */
 862                 if (device == list_first_entry(&active,
 863                                                struct dasd_device, alias_list))
 864                         list_move(&device->alias_list, &lcu->active_devices);
 865         }
 866         spin_unlock_irqrestore(&lcu->lock, flags);
 867 }
 868
 869 static void __stop_device_on_lcu(struct dasd_device *device,
 870                                  struct dasd_device *pos)
 871 {
 872         /* If pos == device then device is already locked! */
 873         if (pos == device) {
 874                 dasd_device_set_stop_bits(pos, DASD_STOPPED_SU);
 875                 return;
 876         }
 877         spin_lock(get_ccwdev_lock(pos->cdev));
 878         dasd_device_set_stop_bits(pos, DASD_STOPPED_SU);
 879         spin_unlock(get_ccwdev_lock(pos->cdev));
 880 }
 881
 882 /*
 883  * This function is called in interrupt context, so the
 884  * cdev lock for device is already locked!
 885  */
 886 static void _stop_all_devices_on_lcu(struct alias_lcu *lcu,
 887                                      struct dasd_device *device)
 888 {
 889         struct alias_pav_group *pavgroup;
 890         struct dasd_device *pos;
 891
 892         list_for_each_entry(pos, &lcu->active_devices, alias_list)
 893                 __stop_device_on_lcu(device, pos);
 894         list_for_each_entry(pos, &lcu->inactive_devices, alias_list)
 895                 __stop_device_on_lcu(device, pos);
 896         list_for_each_entry(pavgroup, &lcu->grouplist, group) {
 897                 list_for_each_entry(pos, &pavgroup->baselist, alias_list)
 898                         __stop_device_on_lcu(device, pos);
 899                 list_for_each_entry(pos, &pavgroup->aliaslist, alias_list)
 900                         __stop_device_on_lcu(device, pos);
 901         }
 902 }
 903
 904 static void _unstop_all_devices_on_lcu(struct alias_lcu *lcu)
 905 {
 906         struct alias_pav_group *pavgroup;
 907         struct dasd_device *device;
 908         unsigned long flags;
 909
 910         list_for_each_entry(device, &lcu->active_devices, alias_list) {
 911                 spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
 912                 dasd_device_remove_stop_bits(device, DASD_STOPPED_SU);
 913                 spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
 914         }
 915
 916         list_for_each_entry(device, &lcu->inactive_devices, alias_list) {
 917                 spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
 918                 dasd_device_remove_stop_bits(device, DASD_STOPPED_SU);
 919                 spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
 920         }
 921
 922         list_for_each_entry(pavgroup, &lcu->grouplist, group) {
 923                 list_for_each_entry(device, &pavgroup->baselist, alias_list) {
 924                         spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
 925                         dasd_device_remove_stop_bits(device, DASD_STOPPED_SU);
 926                         spin_unlock_irqrestore(get_ccwdev_lock(device->cdev),
 927                                                flags);
 928                 }
 929                 list_for_each_entry(device, &pavgroup->aliaslist, alias_list) {
 930                         spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
 931                         dasd_device_remove_stop_bits(device, DASD_STOPPED_SU);
 932                         spin_unlock_irqrestore(get_ccwdev_lock(device->cdev),
 933                                                flags);
 934                 }
 935         }
 936 }
 937
 938 static void summary_unit_check_handling_work(struct work_struct *work)
 939 {
 940         struct alias_lcu *lcu;
 941         struct summary_unit_check_work_data *suc_data;
 942         unsigned long flags;
 943         struct dasd_device *device;
 944
 945         suc_data = container_of(work, struct summary_unit_check_work_data,
 946                                 worker);
 947         lcu = container_of(suc_data, struct alias_lcu, suc_data);
 948         device = suc_data->device;
 949
 950         /* 1. flush alias devices */
 951         flush_all_alias_devices_on_lcu(lcu);
 952
 953         /* 2. reset summary unit check */
 954         spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
 955         dasd_device_remove_stop_bits(device,
 956                                      (DASD_STOPPED_SU | DASD_STOPPED_PENDING));
 957         spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
 958         reset_summary_unit_check(lcu, device, suc_data->reason);
 959
 960         spin_lock_irqsave(&lcu->lock, flags);
 961         _unstop_all_devices_on_lcu(lcu);
 962         _restart_all_base_devices_on_lcu(lcu);
 963         /* 3. read new alias configuration */
 964         _schedule_lcu_update(lcu, device);
 965         lcu->suc_data.device = NULL;
 966         spin_unlock_irqrestore(&lcu->lock, flags);
 967 }
 968
 969 /*
 970  * note: this will be called from int handler context (cdev locked)
 971  */
 972 void dasd_alias_handle_summary_unit_check(struct dasd_device *device,
 973                                           struct irb *irb)
 974 {
 975         struct alias_lcu *lcu;
 976         char reason;
 977         struct dasd_eckd_private *private;
 978         char *sense;
 979
 980         private = (struct dasd_eckd_private *) device->private;
 981
 982         sense = dasd_get_sense(irb);
 983         if (sense) {
 984                 reason = sense[8];
 985                 DBF_DEV_EVENT(DBF_NOTICE, device, "%s %x",
 986                             "eckd handle summary unit check: reason", reason);
 987         } else {
 988                 DBF_DEV_EVENT(DBF_WARNING, device, "%s",
 989                             "eckd handle summary unit check:"
 990                             " no reason code available");
 991                 return;
 992         }
 993
 994         lcu = private->lcu;
 995         if (!lcu) {
 996                 DBF_DEV_EVENT(DBF_WARNING, device, "%s",
 997                             "device not ready to handle summary"
 998                             " unit check (no lcu structure)");
 999                 return;
1000         }
1001         spin_lock(&lcu->lock);
1002         _stop_all_devices_on_lcu(lcu, device);
1003         /* prepare for lcu_update */
1004         private->lcu->flags |= NEED_UAC_UPDATE | UPDATE_PENDING;
1005         /* If this device is about to be removed just return and wait for
1006          * the next interrupt on a different device
1007          */
1008         if (list_empty(&device->alias_list)) {
1009                 DBF_DEV_EVENT(DBF_WARNING, device, "%s",
1010                             "device is in offline processing,"
1011                             " don't do summary unit check handling");
1012                 spin_unlock(&lcu->lock);
1013                 return;
1014         }
1015         if (lcu->suc_data.device) {
1016                 /* already scheduled or running */
1017                 DBF_DEV_EVENT(DBF_WARNING, device, "%s",
1018                             "previous instance of summary unit check worker"
1019                             " still pending");
1020                 spin_unlock(&lcu->lock);
1021                 return ;
1022         }
1023         lcu->suc_data.reason = reason;
1024         lcu->suc_data.device = device;
1025         spin_unlock(&lcu->lock);
1026         schedule_work(&lcu->suc_data.worker);
1027 };