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