drivers/s390/scsi/zfcp_aux.c

   1 /*
   2  * zfcp device driver
   3  *
   4  * Module interface and handling of zfcp data structures.
   5  *
   6  * Copyright IBM Corporation 2002, 2008
   7  */
   8
   9 /*
  10  * Driver authors:
  11  *            Martin Peschke (originator of the driver)
  12  *            Raimund Schroeder
  13  *            Aron Zeh
  14  *            Wolfgang Taphorn
  15  *            Stefan Bader
  16  *            Heiko Carstens (kernel 2.6 port of the driver)
  17  *            Andreas Herrmann
  18  *            Maxim Shchetynin
  19  *            Volker Sameske
  20  *            Ralph Wuerthner
  21  *            Michael Loehr
  22  *            Swen Schillig
  23  *            Christof Schmitt
  24  *            Martin Petermann
  25  *            Sven Schuetz
  26  */
  27
  28 #define KMSG_COMPONENT "zfcp"
  29 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
  30
  31 #include <linux/miscdevice.h>
  32 #include <linux/seq_file.h>
  33 #include "zfcp_ext.h"
  34
  35 #define ZFCP_BUS_ID_SIZE        20
  36
  37 static char *device;
  38
  39 MODULE_AUTHOR("IBM Deutschland Entwicklung GmbH - linux390@de.ibm.com");
  40 MODULE_DESCRIPTION("FCP HBA driver");
  41 MODULE_LICENSE("GPL");
  42
  43 module_param(device, charp, 0400);
  44 MODULE_PARM_DESC(device, "specify initial device");
  45
  46 static int zfcp_reqlist_alloc(struct zfcp_adapter *adapter)
  47 {
  48         int idx;
  49
  50         adapter->req_list = kcalloc(REQUEST_LIST_SIZE, sizeof(struct list_head),
  51                                     GFP_KERNEL);
  52         if (!adapter->req_list)
  53                 return -ENOMEM;
  54
  55         for (idx = 0; idx < REQUEST_LIST_SIZE; idx++)
  56                 INIT_LIST_HEAD(&adapter->req_list[idx]);
  57         return 0;
  58 }
  59
  60 /**
  61  * zfcp_reqlist_isempty - is the request list empty
  62  * @adapter: pointer to struct zfcp_adapter
  63  *
  64  * Returns: true if list is empty, false otherwise
  65  */
  66 int zfcp_reqlist_isempty(struct zfcp_adapter *adapter)
  67 {
  68         unsigned int idx;
  69
  70         for (idx = 0; idx < REQUEST_LIST_SIZE; idx++)
  71                 if (!list_empty(&adapter->req_list[idx]))
  72                         return 0;
  73         return 1;
  74 }
  75
  76 static int __init zfcp_device_setup(char *devstr)
  77 {
  78         char *token;
  79         char *str;
  80
  81         if (!devstr)
  82                 return 0;
  83
  84         /* duplicate devstr and keep the original for sysfs presentation*/
  85         str = kmalloc(strlen(devstr) + 1, GFP_KERNEL);
  86         if (!str)
  87                 return 0;
  88
  89         strcpy(str, devstr);
  90
  91         token = strsep(&str, ",");
  92         if (!token || strlen(token) >= ZFCP_BUS_ID_SIZE)
  93                 goto err_out;
  94         strncpy(zfcp_data.init_busid, token, ZFCP_BUS_ID_SIZE);
  95
  96         token = strsep(&str, ",");
  97         if (!token || strict_strtoull(token, 0,
  98                                 (unsigned long long *) &zfcp_data.init_wwpn))
  99                 goto err_out;
 100
 101         token = strsep(&str, ",");
 102         if (!token || strict_strtoull(token, 0,
 103                                 (unsigned long long *) &zfcp_data.init_fcp_lun))
 104                 goto err_out;
 105
 106         kfree(str);
 107         return 1;
 108
 109  err_out:
 110         kfree(str);
 111         pr_err("%s is not a valid SCSI device\n", devstr);
 112         return 0;
 113 }
 114
 115 static void __init zfcp_init_device_configure(void)
 116 {
 117         struct zfcp_adapter *adapter;
 118         struct zfcp_port *port;
 119         struct zfcp_unit *unit;
 120
 121         down(&zfcp_data.config_sema);
 122         read_lock_irq(&zfcp_data.config_lock);
 123         adapter = zfcp_get_adapter_by_busid(zfcp_data.init_busid);
 124         if (adapter)
 125                 zfcp_adapter_get(adapter);
 126         read_unlock_irq(&zfcp_data.config_lock);
 127
 128         if (!adapter)
 129                 goto out_adapter;
 130         port = zfcp_port_enqueue(adapter, zfcp_data.init_wwpn, 0, 0);
 131         if (IS_ERR(port))
 132                 goto out_port;
 133         unit = zfcp_unit_enqueue(port, zfcp_data.init_fcp_lun);
 134         if (IS_ERR(unit))
 135                 goto out_unit;
 136         up(&zfcp_data.config_sema);
 137         ccw_device_set_online(adapter->ccw_device);
 138
 139         zfcp_erp_wait(adapter);
 140         wait_event(adapter->erp_done_wqh,
 141                    !(atomic_read(&unit->status) &
 142                                 ZFCP_STATUS_UNIT_SCSI_WORK_PENDING));
 143
 144         down(&zfcp_data.config_sema);
 145         zfcp_unit_put(unit);
 146 out_unit:
 147         zfcp_port_put(port);
 148 out_port:
 149         zfcp_adapter_put(adapter);
 150 out_adapter:
 151         up(&zfcp_data.config_sema);
 152         return;
 153 }
 154
 155 static struct kmem_cache *zfcp_cache_create(int size, char *name)
 156 {
 157         int align = 1;
 158         while ((size - align) > 0)
 159                 align <<= 1;
 160         return kmem_cache_create(name , size, align, 0, NULL);
 161 }
 162
 163 static int __init zfcp_module_init(void)
 164 {
 165         int retval = -ENOMEM;
 166
 167         zfcp_data.fsf_req_qtcb_cache = zfcp_cache_create(
 168                         sizeof(struct zfcp_fsf_req_qtcb), "zfcp_fsf");
 169         if (!zfcp_data.fsf_req_qtcb_cache)
 170                 goto out;
 171
 172         zfcp_data.sr_buffer_cache = zfcp_cache_create(
 173                         sizeof(struct fsf_status_read_buffer), "zfcp_sr");
 174         if (!zfcp_data.sr_buffer_cache)
 175                 goto out_sr_cache;
 176
 177         zfcp_data.gid_pn_cache = zfcp_cache_create(
 178                         sizeof(struct zfcp_gid_pn_data), "zfcp_gid");
 179         if (!zfcp_data.gid_pn_cache)
 180                 goto out_gid_cache;
 181
 182         zfcp_data.work_queue = create_singlethread_workqueue("zfcp_wq");
 183
 184         INIT_LIST_HEAD(&zfcp_data.adapter_list_head);
 185         sema_init(&zfcp_data.config_sema, 1);
 186         rwlock_init(&zfcp_data.config_lock);
 187
 188         zfcp_data.scsi_transport_template =
 189                 fc_attach_transport(&zfcp_transport_functions);
 190         if (!zfcp_data.scsi_transport_template)
 191                 goto out_transport;
 192
 193         retval = misc_register(&zfcp_cfdc_misc);
 194         if (retval) {
 195                 pr_err("Registering the misc device zfcp_cfdc failed\n");
 196                 goto out_misc;
 197         }
 198
 199         retval = zfcp_ccw_register();
 200         if (retval) {
 201                 pr_err("The zfcp device driver could not register with "
 202                        "the common I/O layer\n");
 203                 goto out_ccw_register;
 204         }
 205
 206         if (zfcp_device_setup(device))
 207                 zfcp_init_device_configure();
 208
 209         goto out;
 210
 211 out_ccw_register:
 212         misc_deregister(&zfcp_cfdc_misc);
 213 out_misc:
 214         fc_release_transport(zfcp_data.scsi_transport_template);
 215 out_transport:
 216         kmem_cache_destroy(zfcp_data.gid_pn_cache);
 217 out_gid_cache:
 218         kmem_cache_destroy(zfcp_data.sr_buffer_cache);
 219 out_sr_cache:
 220         kmem_cache_destroy(zfcp_data.fsf_req_qtcb_cache);
 221 out:
 222         return retval;
 223 }
 224
 225 module_init(zfcp_module_init);
 226
 227 /**
 228  * zfcp_get_unit_by_lun - find unit in unit list of port by FCP LUN
 229  * @port: pointer to port to search for unit
 230  * @fcp_lun: FCP LUN to search for
 231  *
 232  * Returns: pointer to zfcp_unit or NULL
 233  */
 234 struct zfcp_unit *zfcp_get_unit_by_lun(struct zfcp_port *port, u64 fcp_lun)
 235 {
 236         struct zfcp_unit *unit;
 237
 238         list_for_each_entry(unit, &port->unit_list_head, list)
 239                 if ((unit->fcp_lun == fcp_lun) &&
 240                     !(atomic_read(&unit->status) & ZFCP_STATUS_COMMON_REMOVE))
 241                     return unit;
 242         return NULL;
 243 }
 244
 245 /**
 246  * zfcp_get_port_by_wwpn - find port in port list of adapter by wwpn
 247  * @adapter: pointer to adapter to search for port
 248  * @wwpn: wwpn to search for
 249  *
 250  * Returns: pointer to zfcp_port or NULL
 251  */
 252 struct zfcp_port *zfcp_get_port_by_wwpn(struct zfcp_adapter *adapter,
 253                                         u64 wwpn)
 254 {
 255         struct zfcp_port *port;
 256
 257         list_for_each_entry(port, &adapter->port_list_head, list)
 258                 if ((port->wwpn == wwpn) && !(atomic_read(&port->status) &
 259                       (ZFCP_STATUS_PORT_NO_WWPN | ZFCP_STATUS_COMMON_REMOVE)))
 260                         return port;
 261         return NULL;
 262 }
 263
 264 static void zfcp_sysfs_unit_release(struct device *dev)
 265 {
 266         kfree(container_of(dev, struct zfcp_unit, sysfs_device));
 267 }
 268
 269 /**
 270  * zfcp_unit_enqueue - enqueue unit to unit list of a port.
 271  * @port: pointer to port where unit is added
 272  * @fcp_lun: FCP LUN of unit to be enqueued
 273  * Returns: pointer to enqueued unit on success, ERR_PTR on error
 274  * Locks: config_sema must be held to serialize changes to the unit list
 275  *
 276  * Sets up some unit internal structures and creates sysfs entry.
 277  */
 278 struct zfcp_unit *zfcp_unit_enqueue(struct zfcp_port *port, u64 fcp_lun)
 279 {
 280         struct zfcp_unit *unit;
 281
 282         unit = kzalloc(sizeof(struct zfcp_unit), GFP_KERNEL);
 283         if (!unit)
 284                 return ERR_PTR(-ENOMEM);
 285
 286         atomic_set(&unit->refcount, 0);
 287         init_waitqueue_head(&unit->remove_wq);
 288
 289         unit->port = port;
 290         unit->fcp_lun = fcp_lun;
 291
 292         dev_set_name(&unit->sysfs_device, "0x%016llx",
 293                      (unsigned long long) fcp_lun);
 294         unit->sysfs_device.parent = &port->sysfs_device;
 295         unit->sysfs_device.release = zfcp_sysfs_unit_release;
 296         dev_set_drvdata(&unit->sysfs_device, unit);
 297
 298         /* mark unit unusable as long as sysfs registration is not complete */
 299         atomic_set_mask(ZFCP_STATUS_COMMON_REMOVE, &unit->status);
 300
 301         spin_lock_init(&unit->latencies.lock);
 302         unit->latencies.write.channel.min = 0xFFFFFFFF;
 303         unit->latencies.write.fabric.min = 0xFFFFFFFF;
 304         unit->latencies.read.channel.min = 0xFFFFFFFF;
 305         unit->latencies.read.fabric.min = 0xFFFFFFFF;
 306         unit->latencies.cmd.channel.min = 0xFFFFFFFF;
 307         unit->latencies.cmd.fabric.min = 0xFFFFFFFF;
 308
 309         read_lock_irq(&zfcp_data.config_lock);
 310         if (zfcp_get_unit_by_lun(port, fcp_lun)) {
 311                 read_unlock_irq(&zfcp_data.config_lock);
 312                 goto err_out_free;
 313         }
 314         read_unlock_irq(&zfcp_data.config_lock);
 315
 316         if (device_register(&unit->sysfs_device))
 317                 goto err_out_free;
 318
 319         if (sysfs_create_group(&unit->sysfs_device.kobj,
 320                                &zfcp_sysfs_unit_attrs)) {
 321                 device_unregister(&unit->sysfs_device);
 322                 return ERR_PTR(-EIO);
 323         }
 324
 325         zfcp_unit_get(unit);
 326
 327         write_lock_irq(&zfcp_data.config_lock);
 328         list_add_tail(&unit->list, &port->unit_list_head);
 329         atomic_clear_mask(ZFCP_STATUS_COMMON_REMOVE, &unit->status);
 330         atomic_set_mask(ZFCP_STATUS_COMMON_RUNNING, &unit->status);
 331
 332         write_unlock_irq(&zfcp_data.config_lock);
 333
 334         zfcp_port_get(port);
 335
 336         return unit;
 337
 338 err_out_free:
 339         kfree(unit);
 340         return ERR_PTR(-EINVAL);
 341 }
 342
 343 /**
 344  * zfcp_unit_dequeue - dequeue unit
 345  * @unit: pointer to zfcp_unit
 346  *
 347  * waits until all work is done on unit and removes it then from the unit->list
 348  * of the associated port.
 349  */
 350 void zfcp_unit_dequeue(struct zfcp_unit *unit)
 351 {
 352         wait_event(unit->remove_wq, atomic_read(&unit->refcount) == 0);
 353         write_lock_irq(&zfcp_data.config_lock);
 354         list_del(&unit->list);
 355         write_unlock_irq(&zfcp_data.config_lock);
 356         zfcp_port_put(unit->port);
 357         sysfs_remove_group(&unit->sysfs_device.kobj, &zfcp_sysfs_unit_attrs);
 358         device_unregister(&unit->sysfs_device);
 359 }
 360
 361 static int zfcp_allocate_low_mem_buffers(struct zfcp_adapter *adapter)
 362 {
 363         /* must only be called with zfcp_data.config_sema taken */
 364         adapter->pool.fsf_req_erp =
 365                 mempool_create_slab_pool(1, zfcp_data.fsf_req_qtcb_cache);
 366         if (!adapter->pool.fsf_req_erp)
 367                 return -ENOMEM;
 368
 369         adapter->pool.fsf_req_scsi =
 370                 mempool_create_slab_pool(1, zfcp_data.fsf_req_qtcb_cache);
 371         if (!adapter->pool.fsf_req_scsi)
 372                 return -ENOMEM;
 373
 374         adapter->pool.fsf_req_abort =
 375                 mempool_create_slab_pool(1, zfcp_data.fsf_req_qtcb_cache);
 376         if (!adapter->pool.fsf_req_abort)
 377                 return -ENOMEM;
 378
 379         adapter->pool.fsf_req_status_read =
 380                 mempool_create_kmalloc_pool(FSF_STATUS_READS_RECOM,
 381                                             sizeof(struct zfcp_fsf_req));
 382         if (!adapter->pool.fsf_req_status_read)
 383                 return -ENOMEM;
 384
 385         adapter->pool.data_status_read =
 386                 mempool_create_slab_pool(FSF_STATUS_READS_RECOM,
 387                                          zfcp_data.sr_buffer_cache);
 388         if (!adapter->pool.data_status_read)
 389                 return -ENOMEM;
 390
 391         adapter->pool.data_gid_pn =
 392                 mempool_create_slab_pool(1, zfcp_data.gid_pn_cache);
 393         if (!adapter->pool.data_gid_pn)
 394                 return -ENOMEM;
 395
 396         return 0;
 397 }
 398
 399 static void zfcp_free_low_mem_buffers(struct zfcp_adapter *adapter)
 400 {
 401         /* zfcp_data.config_sema must be held */
 402         if (adapter->pool.fsf_req_erp)
 403                 mempool_destroy(adapter->pool.fsf_req_erp);
 404         if (adapter->pool.fsf_req_scsi)
 405                 mempool_destroy(adapter->pool.fsf_req_scsi);
 406         if (adapter->pool.fsf_req_abort)
 407                 mempool_destroy(adapter->pool.fsf_req_abort);
 408         if (adapter->pool.fsf_req_status_read)
 409                 mempool_destroy(adapter->pool.fsf_req_status_read);
 410         if (adapter->pool.data_status_read)
 411                 mempool_destroy(adapter->pool.data_status_read);
 412         if (adapter->pool.data_gid_pn)
 413                 mempool_destroy(adapter->pool.data_gid_pn);
 414 }
 415
 416 /**
 417  * zfcp_status_read_refill - refill the long running status_read_requests
 418  * @adapter: ptr to struct zfcp_adapter for which the buffers should be refilled
 419  *
 420  * Returns: 0 on success, 1 otherwise
 421  *
 422  * if there are 16 or more status_read requests missing an adapter_reopen
 423  * is triggered
 424  */
 425 int zfcp_status_read_refill(struct zfcp_adapter *adapter)
 426 {
 427         while (atomic_read(&adapter->stat_miss) > 0)
 428                 if (zfcp_fsf_status_read(adapter)) {
 429                         if (atomic_read(&adapter->stat_miss) >= 16) {
 430                                 zfcp_erp_adapter_reopen(adapter, 0, 103, NULL);
 431                                 return 1;
 432                         }
 433                         break;
 434                 } else
 435                         atomic_dec(&adapter->stat_miss);
 436         return 0;
 437 }
 438
 439 static void _zfcp_status_read_scheduler(struct work_struct *work)
 440 {
 441         zfcp_status_read_refill(container_of(work, struct zfcp_adapter,
 442                                              stat_work));
 443 }
 444
 445 static void zfcp_print_sl(struct seq_file *m, struct service_level *sl)
 446 {
 447         struct zfcp_adapter *adapter =
 448                 container_of(sl, struct zfcp_adapter, service_level);
 449
 450         seq_printf(m, "zfcp: %s microcode level %x\n",
 451                    dev_name(&adapter->ccw_device->dev),
 452                    adapter->fsf_lic_version);
 453 }
 454
 455 /**
 456  * zfcp_adapter_enqueue - enqueue a new adapter to the list
 457  * @ccw_device: pointer to the struct cc_device
 458  *
 459  * Returns:     0             if a new adapter was successfully enqueued
 460  *              -ENOMEM       if alloc failed
 461  * Enqueues an adapter at the end of the adapter list in the driver data.
 462  * All adapter internal structures are set up.
 463  * Proc-fs entries are also created.
 464  * locks:       config_sema must be held to serialise changes to the adapter list
 465  */
 466 int zfcp_adapter_enqueue(struct ccw_device *ccw_device)
 467 {
 468         struct zfcp_adapter *adapter;
 469
 470         /*
 471          * Note: It is safe to release the list_lock, as any list changes
 472          * are protected by the config_sema, which must be held to get here
 473          */
 474
 475         adapter = kzalloc(sizeof(struct zfcp_adapter), GFP_KERNEL);
 476         if (!adapter)
 477                 return -ENOMEM;
 478
 479         ccw_device->handler = NULL;
 480         adapter->ccw_device = ccw_device;
 481         atomic_set(&adapter->refcount, 0);
 482
 483         if (zfcp_qdio_allocate(adapter))
 484                 goto qdio_allocate_failed;
 485
 486         if (zfcp_allocate_low_mem_buffers(adapter))
 487                 goto failed_low_mem_buffers;
 488
 489         if (zfcp_reqlist_alloc(adapter))
 490                 goto failed_low_mem_buffers;
 491
 492         if (zfcp_adapter_debug_register(adapter))
 493                 goto debug_register_failed;
 494
 495         init_waitqueue_head(&adapter->remove_wq);
 496         init_waitqueue_head(&adapter->erp_thread_wqh);
 497         init_waitqueue_head(&adapter->erp_done_wqh);
 498
 499         INIT_LIST_HEAD(&adapter->port_list_head);
 500         INIT_LIST_HEAD(&adapter->erp_ready_head);
 501         INIT_LIST_HEAD(&adapter->erp_running_head);
 502
 503         spin_lock_init(&adapter->req_list_lock);
 504
 505         spin_lock_init(&adapter->hba_dbf_lock);
 506         spin_lock_init(&adapter->san_dbf_lock);
 507         spin_lock_init(&adapter->scsi_dbf_lock);
 508         spin_lock_init(&adapter->rec_dbf_lock);
 509         spin_lock_init(&adapter->req_q_lock);
 510
 511         rwlock_init(&adapter->erp_lock);
 512         rwlock_init(&adapter->abort_lock);
 513
 514         sema_init(&adapter->erp_ready_sem, 0);
 515
 516         INIT_WORK(&adapter->stat_work, _zfcp_status_read_scheduler);
 517         INIT_WORK(&adapter->scan_work, _zfcp_scan_ports_later);
 518
 519         adapter->service_level.seq_print = zfcp_print_sl;
 520
 521         /* mark adapter unusable as long as sysfs registration is not complete */
 522         atomic_set_mask(ZFCP_STATUS_COMMON_REMOVE, &adapter->status);
 523
 524         dev_set_drvdata(&ccw_device->dev, adapter);
 525
 526         if (sysfs_create_group(&ccw_device->dev.kobj,
 527                                &zfcp_sysfs_adapter_attrs))
 528                 goto sysfs_failed;
 529
 530         write_lock_irq(&zfcp_data.config_lock);
 531         atomic_clear_mask(ZFCP_STATUS_COMMON_REMOVE, &adapter->status);
 532         list_add_tail(&adapter->list, &zfcp_data.adapter_list_head);
 533         write_unlock_irq(&zfcp_data.config_lock);
 534
 535         zfcp_fc_nameserver_init(adapter);
 536
 537         return 0;
 538
 539 sysfs_failed:
 540         zfcp_adapter_debug_unregister(adapter);
 541 debug_register_failed:
 542         dev_set_drvdata(&ccw_device->dev, NULL);
 543         kfree(adapter->req_list);
 544 failed_low_mem_buffers:
 545         zfcp_free_low_mem_buffers(adapter);
 546 qdio_allocate_failed:
 547         zfcp_qdio_free(adapter);
 548         kfree(adapter);
 549         return -ENOMEM;
 550 }
 551
 552 /**
 553  * zfcp_adapter_dequeue - remove the adapter from the resource list
 554  * @adapter: pointer to struct zfcp_adapter which should be removed
 555  * locks:       adapter list write lock is assumed to be held by caller
 556  */
 557 void zfcp_adapter_dequeue(struct zfcp_adapter *adapter)
 558 {
 559         int retval = 0;
 560         unsigned long flags;
 561
 562         cancel_work_sync(&adapter->scan_work);
 563         cancel_work_sync(&adapter->stat_work);
 564         zfcp_adapter_scsi_unregister(adapter);
 565         sysfs_remove_group(&adapter->ccw_device->dev.kobj,
 566                            &zfcp_sysfs_adapter_attrs);
 567         dev_set_drvdata(&adapter->ccw_device->dev, NULL);
 568         /* sanity check: no pending FSF requests */
 569         spin_lock_irqsave(&adapter->req_list_lock, flags);
 570         retval = zfcp_reqlist_isempty(adapter);
 571         spin_unlock_irqrestore(&adapter->req_list_lock, flags);
 572         if (!retval)
 573                 return;
 574
 575         zfcp_adapter_debug_unregister(adapter);
 576
 577         /* remove specified adapter data structure from list */
 578         write_lock_irq(&zfcp_data.config_lock);
 579         list_del(&adapter->list);
 580         write_unlock_irq(&zfcp_data.config_lock);
 581
 582         zfcp_qdio_free(adapter);
 583
 584         zfcp_free_low_mem_buffers(adapter);
 585         kfree(adapter->req_list);
 586         kfree(adapter->fc_stats);
 587         kfree(adapter->stats_reset_data);
 588         kfree(adapter);
 589 }
 590
 591 static void zfcp_sysfs_port_release(struct device *dev)
 592 {
 593         kfree(container_of(dev, struct zfcp_port, sysfs_device));
 594 }
 595
 596 /**
 597  * zfcp_port_enqueue - enqueue port to port list of adapter
 598  * @adapter: adapter where remote port is added
 599  * @wwpn: WWPN of the remote port to be enqueued
 600  * @status: initial status for the port
 601  * @d_id: destination id of the remote port to be enqueued
 602  * Returns: pointer to enqueued port on success, ERR_PTR on error
 603  * Locks: config_sema must be held to serialize changes to the port list
 604  *
 605  * All port internal structures are set up and the sysfs entry is generated.
 606  * d_id is used to enqueue ports with a well known address like the Directory
 607  * Service for nameserver lookup.
 608  */
 609 struct zfcp_port *zfcp_port_enqueue(struct zfcp_adapter *adapter, u64 wwpn,
 610                                      u32 status, u32 d_id)
 611 {
 612         struct zfcp_port *port;
 613         int retval;
 614
 615         port = kzalloc(sizeof(struct zfcp_port), GFP_KERNEL);
 616         if (!port)
 617                 return ERR_PTR(-ENOMEM);
 618
 619         init_waitqueue_head(&port->remove_wq);
 620         INIT_LIST_HEAD(&port->unit_list_head);
 621         INIT_WORK(&port->gid_pn_work, zfcp_erp_port_strategy_open_lookup);
 622
 623         port->adapter = adapter;
 624         port->d_id = d_id;
 625         port->wwpn = wwpn;
 626
 627         /* mark port unusable as long as sysfs registration is not complete */
 628         atomic_set_mask(status | ZFCP_STATUS_COMMON_REMOVE, &port->status);
 629         atomic_set(&port->refcount, 0);
 630
 631         dev_set_name(&port->sysfs_device, "0x%016llx",
 632                      (unsigned long long)wwpn);
 633         port->sysfs_device.parent = &adapter->ccw_device->dev;
 634
 635         port->sysfs_device.release = zfcp_sysfs_port_release;
 636         dev_set_drvdata(&port->sysfs_device, port);
 637
 638         read_lock_irq(&zfcp_data.config_lock);
 639         if (!(status & ZFCP_STATUS_PORT_NO_WWPN))
 640                 if (zfcp_get_port_by_wwpn(adapter, wwpn)) {
 641                         read_unlock_irq(&zfcp_data.config_lock);
 642                         goto err_out_free;
 643                 }
 644         read_unlock_irq(&zfcp_data.config_lock);
 645
 646         if (device_register(&port->sysfs_device))
 647                 goto err_out_free;
 648
 649         retval = sysfs_create_group(&port->sysfs_device.kobj,
 650                                     &zfcp_sysfs_port_attrs);
 651
 652         if (retval) {
 653                 device_unregister(&port->sysfs_device);
 654                 goto err_out;
 655         }
 656
 657         zfcp_port_get(port);
 658
 659         write_lock_irq(&zfcp_data.config_lock);
 660         list_add_tail(&port->list, &adapter->port_list_head);
 661         atomic_clear_mask(ZFCP_STATUS_COMMON_REMOVE, &port->status);
 662         atomic_set_mask(ZFCP_STATUS_COMMON_RUNNING, &port->status);
 663
 664         write_unlock_irq(&zfcp_data.config_lock);
 665
 666         zfcp_adapter_get(adapter);
 667         return port;
 668
 669 err_out_free:
 670         kfree(port);
 671 err_out:
 672         return ERR_PTR(-EINVAL);
 673 }
 674
 675 /**
 676  * zfcp_port_dequeue - dequeues a port from the port list of the adapter
 677  * @port: pointer to struct zfcp_port which should be removed
 678  */
 679 void zfcp_port_dequeue(struct zfcp_port *port)
 680 {
 681         wait_event(port->remove_wq, atomic_read(&port->refcount) == 0);
 682         write_lock_irq(&zfcp_data.config_lock);
 683         list_del(&port->list);
 684         write_unlock_irq(&zfcp_data.config_lock);
 685         if (port->rport)
 686                 fc_remote_port_delete(port->rport);
 687         port->rport = NULL;
 688         zfcp_adapter_put(port->adapter);
 689         sysfs_remove_group(&port->sysfs_device.kobj, &zfcp_sysfs_port_attrs);
 690         device_unregister(&port->sysfs_device);
 691 }
 692
 693 /**
 694  * zfcp_sg_free_table - free memory used by scatterlists
 695  * @sg: pointer to scatterlist
 696  * @count: number of scatterlist which are to be free'ed
 697  * the scatterlist are expected to reference pages always
 698  */
 699 void zfcp_sg_free_table(struct scatterlist *sg, int count)
 700 {
 701         int i;
 702
 703         for (i = 0; i < count; i++, sg++)
 704                 if (sg)
 705                         free_page((unsigned long) sg_virt(sg));
 706                 else
 707                         break;
 708 }
 709
 710 /**
 711  * zfcp_sg_setup_table - init scatterlist and allocate, assign buffers
 712  * @sg: pointer to struct scatterlist
 713  * @count: number of scatterlists which should be assigned with buffers
 714  * of size page
 715  *
 716  * Returns: 0 on success, -ENOMEM otherwise
 717  */
 718 int zfcp_sg_setup_table(struct scatterlist *sg, int count)
 719 {
 720         void *addr;
 721         int i;
 722
 723         sg_init_table(sg, count);
 724         for (i = 0; i < count; i++, sg++) {
 725                 addr = (void *) get_zeroed_page(GFP_KERNEL);
 726                 if (!addr) {
 727                         zfcp_sg_free_table(sg, i);
 728                         return -ENOMEM;
 729                 }
 730                 sg_set_buf(sg, addr, PAGE_SIZE);
 731         }
 732         return 0;
 733 }