drivers/scsi/scsi_transport_srp.c

   1 /*
   2  * SCSI RDMA (SRP) transport class
   3  *
   4  * Copyright (C) 2007 FUJITA Tomonori <tomof@acm.org>
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License as
   8  * published by the Free Software Foundation, version 2 of the
   9  * License.
  10  *
  11  * This program is distributed in the hope that it will be useful, but
  12  * WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14  * General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
  19  * 02110-1301 USA
  20  */
  21 #include <linux/init.h>
  22 #include <linux/module.h>
  23 #include <linux/jiffies.h>
  24 #include <linux/err.h>
  25 #include <linux/slab.h>
  26 #include <linux/string.h>
  27 #include <linux/delay.h>
  28
  29 #include <scsi/scsi.h>
  30 #include <scsi/scsi_cmnd.h>
  31 #include <scsi/scsi_device.h>
  32 #include <scsi/scsi_host.h>
  33 #include <scsi/scsi_transport.h>
  34 #include <scsi/scsi_transport_srp.h>
  35 #include "scsi_priv.h"
  36 #include "scsi_transport_srp_internal.h"
  37
  38 struct srp_host_attrs {
  39         atomic_t next_port_id;
  40 };
  41 #define to_srp_host_attrs(host) ((struct srp_host_attrs *)(host)->shost_data)
  42
  43 #define SRP_HOST_ATTRS 0
  44 #define SRP_RPORT_ATTRS 6
  45
  46 struct srp_internal {
  47         struct scsi_transport_template t;
  48         struct srp_function_template *f;
  49
  50         struct device_attribute *host_attrs[SRP_HOST_ATTRS + 1];
  51
  52         struct device_attribute *rport_attrs[SRP_RPORT_ATTRS + 1];
  53         struct transport_container rport_attr_cont;
  54 };
  55
  56 #define to_srp_internal(tmpl) container_of(tmpl, struct srp_internal, t)
  57
  58 #define dev_to_rport(d) container_of(d, struct srp_rport, dev)
  59 #define transport_class_to_srp_rport(dev) dev_to_rport((dev)->parent)
  60 static inline struct Scsi_Host *rport_to_shost(struct srp_rport *r)
  61 {
  62         return dev_to_shost(r->dev.parent);
  63 }
  64
  65 /**
  66  * srp_tmo_valid() - check timeout combination validity
  67  *
  68  * The combination of the timeout parameters must be such that SCSI commands
  69  * are finished in a reasonable time. Hence do not allow the fast I/O fail
  70  * timeout to exceed SCSI_DEVICE_BLOCK_MAX_TIMEOUT. Furthermore, these
  71  * parameters must be such that multipath can detect failed paths timely.
  72  * Hence do not allow both parameters to be disabled simultaneously.
  73  */
  74 int srp_tmo_valid(int fast_io_fail_tmo, int dev_loss_tmo)
  75 {
  76         if (fast_io_fail_tmo < 0 && dev_loss_tmo < 0)
  77                 return -EINVAL;
  78         if (fast_io_fail_tmo > SCSI_DEVICE_BLOCK_MAX_TIMEOUT)
  79                 return -EINVAL;
  80         if (dev_loss_tmo >= LONG_MAX / HZ)
  81                 return -EINVAL;
  82         if (fast_io_fail_tmo >= 0 && dev_loss_tmo >= 0 &&
  83             fast_io_fail_tmo >= dev_loss_tmo)
  84                 return -EINVAL;
  85         return 0;
  86 }
  87 EXPORT_SYMBOL_GPL(srp_tmo_valid);
  88
  89 static int srp_host_setup(struct transport_container *tc, struct device *dev,
  90                           struct device *cdev)
  91 {
  92         struct Scsi_Host *shost = dev_to_shost(dev);
  93         struct srp_host_attrs *srp_host = to_srp_host_attrs(shost);
  94
  95         atomic_set(&srp_host->next_port_id, 0);
  96         return 0;
  97 }
  98
  99 static DECLARE_TRANSPORT_CLASS(srp_host_class, "srp_host", srp_host_setup,
 100                                NULL, NULL);
 101
 102 static DECLARE_TRANSPORT_CLASS(srp_rport_class, "srp_remote_ports",
 103                                NULL, NULL, NULL);
 104
 105 #define SRP_PID(p) \
 106         (p)->port_id[0], (p)->port_id[1], (p)->port_id[2], (p)->port_id[3], \
 107         (p)->port_id[4], (p)->port_id[5], (p)->port_id[6], (p)->port_id[7], \
 108         (p)->port_id[8], (p)->port_id[9], (p)->port_id[10], (p)->port_id[11], \
 109         (p)->port_id[12], (p)->port_id[13], (p)->port_id[14], (p)->port_id[15]
 110
 111 #define SRP_PID_FMT "%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:" \
 112         "%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x"
 113
 114 static ssize_t
 115 show_srp_rport_id(struct device *dev, struct device_attribute *attr,
 116                   char *buf)
 117 {
 118         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 119         return sprintf(buf, SRP_PID_FMT "\n", SRP_PID(rport));
 120 }
 121
 122 static DEVICE_ATTR(port_id, S_IRUGO, show_srp_rport_id, NULL);
 123
 124 static const struct {
 125         u32 value;
 126         char *name;
 127 } srp_rport_role_names[] = {
 128         {SRP_RPORT_ROLE_INITIATOR, "SRP Initiator"},
 129         {SRP_RPORT_ROLE_TARGET, "SRP Target"},
 130 };
 131
 132 static ssize_t
 133 show_srp_rport_roles(struct device *dev, struct device_attribute *attr,
 134                      char *buf)
 135 {
 136         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 137         int i;
 138         char *name = NULL;
 139
 140         for (i = 0; i < ARRAY_SIZE(srp_rport_role_names); i++)
 141                 if (srp_rport_role_names[i].value == rport->roles) {
 142                         name = srp_rport_role_names[i].name;
 143                         break;
 144                 }
 145         return sprintf(buf, "%s\n", name ? : "unknown");
 146 }
 147
 148 static DEVICE_ATTR(roles, S_IRUGO, show_srp_rport_roles, NULL);
 149
 150 static ssize_t store_srp_rport_delete(struct device *dev,
 151                                       struct device_attribute *attr,
 152                                       const char *buf, size_t count)
 153 {
 154         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 155         struct Scsi_Host *shost = dev_to_shost(dev);
 156         struct srp_internal *i = to_srp_internal(shost->transportt);
 157
 158         if (i->f->rport_delete) {
 159                 i->f->rport_delete(rport);
 160                 return count;
 161         } else {
 162                 return -ENOSYS;
 163         }
 164 }
 165
 166 static DEVICE_ATTR(delete, S_IWUSR, NULL, store_srp_rport_delete);
 167
 168 static ssize_t show_srp_rport_state(struct device *dev,
 169                                     struct device_attribute *attr,
 170                                     char *buf)
 171 {
 172         static const char *const state_name[] = {
 173                 [SRP_RPORT_RUNNING]     = "running",
 174                 [SRP_RPORT_BLOCKED]     = "blocked",
 175                 [SRP_RPORT_FAIL_FAST]   = "fail-fast",
 176                 [SRP_RPORT_LOST]        = "lost",
 177         };
 178         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 179         enum srp_rport_state state = rport->state;
 180
 181         return sprintf(buf, "%s\n",
 182                        (unsigned)state < ARRAY_SIZE(state_name) ?
 183                        state_name[state] : "???");
 184 }
 185
 186 static DEVICE_ATTR(state, S_IRUGO, show_srp_rport_state, NULL);
 187
 188 static ssize_t srp_show_tmo(char *buf, int tmo)
 189 {
 190         return tmo >= 0 ? sprintf(buf, "%d\n", tmo) : sprintf(buf, "off\n");
 191 }
 192
 193 static int srp_parse_tmo(int *tmo, const char *buf)
 194 {
 195         int res = 0;
 196
 197         if (strncmp(buf, "off", 3) != 0)
 198                 res = kstrtoint(buf, 0, tmo);
 199         else
 200                 *tmo = -1;
 201
 202         return res;
 203 }
 204
 205 static ssize_t show_srp_rport_fast_io_fail_tmo(struct device *dev,
 206                                                struct device_attribute *attr,
 207                                                char *buf)
 208 {
 209         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 210
 211         return srp_show_tmo(buf, rport->fast_io_fail_tmo);
 212 }
 213
 214 static ssize_t store_srp_rport_fast_io_fail_tmo(struct device *dev,
 215                                                 struct device_attribute *attr,
 216                                                 const char *buf, size_t count)
 217 {
 218         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 219         int res;
 220         int fast_io_fail_tmo;
 221
 222         res = srp_parse_tmo(&fast_io_fail_tmo, buf);
 223         if (res)
 224                 goto out;
 225         res = srp_tmo_valid(fast_io_fail_tmo, rport->dev_loss_tmo);
 226         if (res)
 227                 goto out;
 228         rport->fast_io_fail_tmo = fast_io_fail_tmo;
 229         res = count;
 230
 231 out:
 232         return res;
 233 }
 234
 235 static DEVICE_ATTR(fast_io_fail_tmo, S_IRUGO | S_IWUSR,
 236                    show_srp_rport_fast_io_fail_tmo,
 237                    store_srp_rport_fast_io_fail_tmo);
 238
 239 static ssize_t show_srp_rport_dev_loss_tmo(struct device *dev,
 240                                            struct device_attribute *attr,
 241                                            char *buf)
 242 {
 243         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 244
 245         return srp_show_tmo(buf, rport->dev_loss_tmo);
 246 }
 247
 248 static ssize_t store_srp_rport_dev_loss_tmo(struct device *dev,
 249                                             struct device_attribute *attr,
 250                                             const char *buf, size_t count)
 251 {
 252         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 253         int res;
 254         int dev_loss_tmo;
 255
 256         res = srp_parse_tmo(&dev_loss_tmo, buf);
 257         if (res)
 258                 goto out;
 259         res = srp_tmo_valid(rport->fast_io_fail_tmo, dev_loss_tmo);
 260         if (res)
 261                 goto out;
 262         rport->dev_loss_tmo = dev_loss_tmo;
 263         res = count;
 264
 265 out:
 266         return res;
 267 }
 268
 269 static DEVICE_ATTR(dev_loss_tmo, S_IRUGO | S_IWUSR,
 270                    show_srp_rport_dev_loss_tmo,
 271                    store_srp_rport_dev_loss_tmo);
 272
 273 static int srp_rport_set_state(struct srp_rport *rport,
 274                                enum srp_rport_state new_state)
 275 {
 276         enum srp_rport_state old_state = rport->state;
 277
 278         lockdep_assert_held(&rport->mutex);
 279
 280         switch (new_state) {
 281         case SRP_RPORT_RUNNING:
 282                 switch (old_state) {
 283                 case SRP_RPORT_LOST:
 284                         goto invalid;
 285                 default:
 286                         break;
 287                 }
 288                 break;
 289         case SRP_RPORT_BLOCKED:
 290                 switch (old_state) {
 291                 case SRP_RPORT_RUNNING:
 292                         break;
 293                 default:
 294                         goto invalid;
 295                 }
 296                 break;
 297         case SRP_RPORT_FAIL_FAST:
 298                 switch (old_state) {
 299                 case SRP_RPORT_LOST:
 300                         goto invalid;
 301                 default:
 302                         break;
 303                 }
 304                 break;
 305         case SRP_RPORT_LOST:
 306                 break;
 307         }
 308         rport->state = new_state;
 309         return 0;
 310
 311 invalid:
 312         return -EINVAL;
 313 }
 314
 315 static void __rport_fail_io_fast(struct srp_rport *rport)
 316 {
 317         struct Scsi_Host *shost = rport_to_shost(rport);
 318         struct srp_internal *i;
 319
 320         lockdep_assert_held(&rport->mutex);
 321
 322         if (srp_rport_set_state(rport, SRP_RPORT_FAIL_FAST))
 323                 return;
 324         scsi_target_unblock(rport->dev.parent, SDEV_TRANSPORT_OFFLINE);
 325
 326         /* Involve the LLD if possible to terminate all I/O on the rport. */
 327         i = to_srp_internal(shost->transportt);
 328         if (i->f->terminate_rport_io)
 329                 i->f->terminate_rport_io(rport);
 330 }
 331
 332 /**
 333  * rport_fast_io_fail_timedout() - fast I/O failure timeout handler
 334  */
 335 static void rport_fast_io_fail_timedout(struct work_struct *work)
 336 {
 337         struct srp_rport *rport = container_of(to_delayed_work(work),
 338                                         struct srp_rport, fast_io_fail_work);
 339         struct Scsi_Host *shost = rport_to_shost(rport);
 340
 341         pr_info("fast_io_fail_tmo expired for SRP %s / %s.\n",
 342                 dev_name(&rport->dev), dev_name(&shost->shost_gendev));
 343
 344         mutex_lock(&rport->mutex);
 345         if (rport->state == SRP_RPORT_BLOCKED)
 346                 __rport_fail_io_fast(rport);
 347         mutex_unlock(&rport->mutex);
 348 }
 349
 350 /**
 351  * rport_dev_loss_timedout() - device loss timeout handler
 352  */
 353 static void rport_dev_loss_timedout(struct work_struct *work)
 354 {
 355         struct srp_rport *rport = container_of(to_delayed_work(work),
 356                                         struct srp_rport, dev_loss_work);
 357         struct Scsi_Host *shost = rport_to_shost(rport);
 358         struct srp_internal *i = to_srp_internal(shost->transportt);
 359
 360         pr_info("dev_loss_tmo expired for SRP %s / %s.\n",
 361                 dev_name(&rport->dev), dev_name(&shost->shost_gendev));
 362
 363         mutex_lock(&rport->mutex);
 364         WARN_ON(srp_rport_set_state(rport, SRP_RPORT_LOST) != 0);
 365         scsi_target_unblock(rport->dev.parent, SDEV_TRANSPORT_OFFLINE);
 366         mutex_unlock(&rport->mutex);
 367
 368         i->f->rport_delete(rport);
 369 }
 370
 371 static void __srp_start_tl_fail_timers(struct srp_rport *rport)
 372 {
 373         struct Scsi_Host *shost = rport_to_shost(rport);
 374         int fast_io_fail_tmo, dev_loss_tmo;
 375
 376         lockdep_assert_held(&rport->mutex);
 377
 378         if (!rport->deleted) {
 379                 fast_io_fail_tmo = rport->fast_io_fail_tmo;
 380                 dev_loss_tmo = rport->dev_loss_tmo;
 381                 pr_debug("%s current state: %d\n",
 382                          dev_name(&shost->shost_gendev), rport->state);
 383
 384                 if (fast_io_fail_tmo >= 0 &&
 385                     srp_rport_set_state(rport, SRP_RPORT_BLOCKED) == 0) {
 386                         pr_debug("%s new state: %d\n",
 387                                  dev_name(&shost->shost_gendev),
 388                                  rport->state);
 389                         scsi_target_block(&shost->shost_gendev);
 390                         queue_delayed_work(system_long_wq,
 391                                            &rport->fast_io_fail_work,
 392                                            1UL * fast_io_fail_tmo * HZ);
 393                 }
 394                 if (dev_loss_tmo >= 0)
 395                         queue_delayed_work(system_long_wq,
 396                                            &rport->dev_loss_work,
 397                                            1UL * dev_loss_tmo * HZ);
 398         } else {
 399                 pr_debug("%s has already been deleted\n",
 400                          dev_name(&shost->shost_gendev));
 401                 srp_rport_set_state(rport, SRP_RPORT_FAIL_FAST);
 402                 scsi_target_unblock(&shost->shost_gendev,
 403                                     SDEV_TRANSPORT_OFFLINE);
 404         }
 405 }
 406
 407 /**
 408  * srp_start_tl_fail_timers() - start the transport layer failure timers
 409  *
 410  * Start the transport layer fast I/O failure and device loss timers. Do not
 411  * modify a timer that was already started.
 412  */
 413 void srp_start_tl_fail_timers(struct srp_rport *rport)
 414 {
 415         mutex_lock(&rport->mutex);
 416         __srp_start_tl_fail_timers(rport);
 417         mutex_unlock(&rport->mutex);
 418 }
 419 EXPORT_SYMBOL(srp_start_tl_fail_timers);
 420
 421 /**
 422  * scsi_request_fn_active() - number of kernel threads inside scsi_request_fn()
 423  */
 424 static int scsi_request_fn_active(struct Scsi_Host *shost)
 425 {
 426         struct scsi_device *sdev;
 427         struct request_queue *q;
 428         int request_fn_active = 0;
 429
 430         shost_for_each_device(sdev, shost) {
 431                 q = sdev->request_queue;
 432
 433                 spin_lock_irq(q->queue_lock);
 434                 request_fn_active += q->request_fn_active;
 435                 spin_unlock_irq(q->queue_lock);
 436         }
 437
 438         return request_fn_active;
 439 }
 440
 441 /**
 442  * srp_reconnect_rport() - reconnect to an SRP target port
 443  *
 444  * Blocks SCSI command queueing before invoking reconnect() such that
 445  * queuecommand() won't be invoked concurrently with reconnect() from outside
 446  * the SCSI EH. This is important since a reconnect() implementation may
 447  * reallocate resources needed by queuecommand().
 448  *
 449  * Notes:
 450  * - This function neither waits until outstanding requests have finished nor
 451  *   tries to abort these. It is the responsibility of the reconnect()
 452  *   function to finish outstanding commands before reconnecting to the target
 453  *   port.
 454  * - It is the responsibility of the caller to ensure that the resources
 455  *   reallocated by the reconnect() function won't be used while this function
 456  *   is in progress. One possible strategy is to invoke this function from
 457  *   the context of the SCSI EH thread only. Another possible strategy is to
 458  *   lock the rport mutex inside each SCSI LLD callback that can be invoked by
 459  *   the SCSI EH (the scsi_host_template.eh_*() functions and also the
 460  *   scsi_host_template.queuecommand() function).
 461  */
 462 int srp_reconnect_rport(struct srp_rport *rport)
 463 {
 464         struct Scsi_Host *shost = rport_to_shost(rport);
 465         struct srp_internal *i = to_srp_internal(shost->transportt);
 466         struct scsi_device *sdev;
 467         int res;
 468
 469         pr_debug("SCSI host %s\n", dev_name(&shost->shost_gendev));
 470
 471         res = mutex_lock_interruptible(&rport->mutex);
 472         if (res)
 473                 goto out;
 474         scsi_target_block(&shost->shost_gendev);
 475         while (scsi_request_fn_active(shost))
 476                 msleep(20);
 477         res = i->f->reconnect(rport);
 478         pr_debug("%s (state %d): transport.reconnect() returned %d\n",
 479                  dev_name(&shost->shost_gendev), rport->state, res);
 480         if (res == 0) {
 481                 cancel_delayed_work(&rport->fast_io_fail_work);
 482                 cancel_delayed_work(&rport->dev_loss_work);
 483
 484                 srp_rport_set_state(rport, SRP_RPORT_RUNNING);
 485                 scsi_target_unblock(&shost->shost_gendev, SDEV_RUNNING);
 486                 /*
 487                  * If the SCSI error handler has offlined one or more devices,
 488                  * invoking scsi_target_unblock() won't change the state of
 489                  * these devices into running so do that explicitly.
 490                  */
 491                 spin_lock_irq(shost->host_lock);
 492                 __shost_for_each_device(sdev, shost)
 493                         if (sdev->sdev_state == SDEV_OFFLINE)
 494                                 sdev->sdev_state = SDEV_RUNNING;
 495                 spin_unlock_irq(shost->host_lock);
 496         } else if (rport->state == SRP_RPORT_RUNNING) {
 497                 /*
 498                  * srp_reconnect_rport() was invoked with fast_io_fail
 499                  * off. Mark the port as failed and start the TL failure
 500                  * timers if these had not yet been started.
 501                  */
 502                 __rport_fail_io_fast(rport);
 503                 scsi_target_unblock(&shost->shost_gendev,
 504                                     SDEV_TRANSPORT_OFFLINE);
 505                 __srp_start_tl_fail_timers(rport);
 506         } else if (rport->state != SRP_RPORT_BLOCKED) {
 507                 scsi_target_unblock(&shost->shost_gendev,
 508                                     SDEV_TRANSPORT_OFFLINE);
 509         }
 510         mutex_unlock(&rport->mutex);
 511
 512 out:
 513         return res;
 514 }
 515 EXPORT_SYMBOL(srp_reconnect_rport);
 516
 517 /**
 518  * srp_timed_out() - SRP transport intercept of the SCSI timeout EH
 519  *
 520  * If a timeout occurs while an rport is in the blocked state, ask the SCSI
 521  * EH to continue waiting (BLK_EH_RESET_TIMER). Otherwise let the SCSI core
 522  * handle the timeout (BLK_EH_NOT_HANDLED).
 523  *
 524  * Note: This function is called from soft-IRQ context and with the request
 525  * queue lock held.
 526  */
 527 static enum blk_eh_timer_return srp_timed_out(struct scsi_cmnd *scmd)
 528 {
 529         struct scsi_device *sdev = scmd->device;
 530         struct Scsi_Host *shost = sdev->host;
 531         struct srp_internal *i = to_srp_internal(shost->transportt);
 532
 533         pr_debug("timeout for sdev %s\n", dev_name(&sdev->sdev_gendev));
 534         return i->f->reset_timer_if_blocked && scsi_device_blocked(sdev) ?
 535                 BLK_EH_RESET_TIMER : BLK_EH_NOT_HANDLED;
 536 }
 537
 538 static void srp_rport_release(struct device *dev)
 539 {
 540         struct srp_rport *rport = dev_to_rport(dev);
 541
 542         cancel_delayed_work_sync(&rport->fast_io_fail_work);
 543         cancel_delayed_work_sync(&rport->dev_loss_work);
 544
 545         put_device(dev->parent);
 546         kfree(rport);
 547 }
 548
 549 static int scsi_is_srp_rport(const struct device *dev)
 550 {
 551         return dev->release == srp_rport_release;
 552 }
 553
 554 static int srp_rport_match(struct attribute_container *cont,
 555                            struct device *dev)
 556 {
 557         struct Scsi_Host *shost;
 558         struct srp_internal *i;
 559
 560         if (!scsi_is_srp_rport(dev))
 561                 return 0;
 562
 563         shost = dev_to_shost(dev->parent);
 564         if (!shost->transportt)
 565                 return 0;
 566         if (shost->transportt->host_attrs.ac.class != &srp_host_class.class)
 567                 return 0;
 568
 569         i = to_srp_internal(shost->transportt);
 570         return &i->rport_attr_cont.ac == cont;
 571 }
 572
 573 static int srp_host_match(struct attribute_container *cont, struct device *dev)
 574 {
 575         struct Scsi_Host *shost;
 576         struct srp_internal *i;
 577
 578         if (!scsi_is_host_device(dev))
 579                 return 0;
 580
 581         shost = dev_to_shost(dev);
 582         if (!shost->transportt)
 583                 return 0;
 584         if (shost->transportt->host_attrs.ac.class != &srp_host_class.class)
 585                 return 0;
 586
 587         i = to_srp_internal(shost->transportt);
 588         return &i->t.host_attrs.ac == cont;
 589 }
 590
 591 /**
 592  * srp_rport_get() - increment rport reference count
 593  */
 594 void srp_rport_get(struct srp_rport *rport)
 595 {
 596         get_device(&rport->dev);
 597 }
 598 EXPORT_SYMBOL(srp_rport_get);
 599
 600 /**
 601  * srp_rport_put() - decrement rport reference count
 602  */
 603 void srp_rport_put(struct srp_rport *rport)
 604 {
 605         put_device(&rport->dev);
 606 }
 607 EXPORT_SYMBOL(srp_rport_put);
 608
 609 /**
 610  * srp_rport_add - add a SRP remote port to the device hierarchy
 611  * @shost:      scsi host the remote port is connected to.
 612  * @ids:        The port id for the remote port.
 613  *
 614  * Publishes a port to the rest of the system.
 615  */
 616 struct srp_rport *srp_rport_add(struct Scsi_Host *shost,
 617                                 struct srp_rport_identifiers *ids)
 618 {
 619         struct srp_rport *rport;
 620         struct device *parent = &shost->shost_gendev;
 621         struct srp_internal *i = to_srp_internal(shost->transportt);
 622         int id, ret;
 623
 624         rport = kzalloc(sizeof(*rport), GFP_KERNEL);
 625         if (!rport)
 626                 return ERR_PTR(-ENOMEM);
 627
 628         mutex_init(&rport->mutex);
 629
 630         device_initialize(&rport->dev);
 631
 632         rport->dev.parent = get_device(parent);
 633         rport->dev.release = srp_rport_release;
 634
 635         memcpy(rport->port_id, ids->port_id, sizeof(rport->port_id));
 636         rport->roles = ids->roles;
 637
 638         rport->fast_io_fail_tmo = i->f->fast_io_fail_tmo ?
 639                 *i->f->fast_io_fail_tmo : 15;
 640         rport->dev_loss_tmo = i->f->dev_loss_tmo ? *i->f->dev_loss_tmo : 60;
 641         INIT_DELAYED_WORK(&rport->fast_io_fail_work,
 642                           rport_fast_io_fail_timedout);
 643         INIT_DELAYED_WORK(&rport->dev_loss_work, rport_dev_loss_timedout);
 644
 645         id = atomic_inc_return(&to_srp_host_attrs(shost)->next_port_id);
 646         dev_set_name(&rport->dev, "port-%d:%d", shost->host_no, id);
 647
 648         transport_setup_device(&rport->dev);
 649
 650         ret = device_add(&rport->dev);
 651         if (ret) {
 652                 transport_destroy_device(&rport->dev);
 653                 put_device(&rport->dev);
 654                 return ERR_PTR(ret);
 655         }
 656
 657         if (shost->active_mode & MODE_TARGET &&
 658             ids->roles == SRP_RPORT_ROLE_INITIATOR) {
 659                 ret = srp_tgt_it_nexus_create(shost, (unsigned long)rport,
 660                                               rport->port_id);
 661                 if (ret) {
 662                         device_del(&rport->dev);
 663                         transport_destroy_device(&rport->dev);
 664                         put_device(&rport->dev);
 665                         return ERR_PTR(ret);
 666                 }
 667         }
 668
 669         transport_add_device(&rport->dev);
 670         transport_configure_device(&rport->dev);
 671
 672         return rport;
 673 }
 674 EXPORT_SYMBOL_GPL(srp_rport_add);
 675
 676 /**
 677  * srp_rport_del  -  remove a SRP remote port
 678  * @rport:      SRP remote port to remove
 679  *
 680  * Removes the specified SRP remote port.
 681  */
 682 void srp_rport_del(struct srp_rport *rport)
 683 {
 684         struct device *dev = &rport->dev;
 685         struct Scsi_Host *shost = dev_to_shost(dev->parent);
 686
 687         if (shost->active_mode & MODE_TARGET &&
 688             rport->roles == SRP_RPORT_ROLE_INITIATOR)
 689                 srp_tgt_it_nexus_destroy(shost, (unsigned long)rport);
 690
 691         transport_remove_device(dev);
 692         device_del(dev);
 693         transport_destroy_device(dev);
 694
 695         mutex_lock(&rport->mutex);
 696         if (rport->state == SRP_RPORT_BLOCKED)
 697                 __rport_fail_io_fast(rport);
 698         rport->deleted = true;
 699         mutex_unlock(&rport->mutex);
 700
 701         put_device(dev);
 702 }
 703 EXPORT_SYMBOL_GPL(srp_rport_del);
 704
 705 static int do_srp_rport_del(struct device *dev, void *data)
 706 {
 707         if (scsi_is_srp_rport(dev))
 708                 srp_rport_del(dev_to_rport(dev));
 709         return 0;
 710 }
 711
 712 /**
 713  * srp_remove_host  -  tear down a Scsi_Host's SRP data structures
 714  * @shost:      Scsi Host that is torn down
 715  *
 716  * Removes all SRP remote ports for a given Scsi_Host.
 717  * Must be called just before scsi_remove_host for SRP HBAs.
 718  */
 719 void srp_remove_host(struct Scsi_Host *shost)
 720 {
 721         device_for_each_child(&shost->shost_gendev, NULL, do_srp_rport_del);
 722 }
 723 EXPORT_SYMBOL_GPL(srp_remove_host);
 724
 725 static int srp_tsk_mgmt_response(struct Scsi_Host *shost, u64 nexus, u64 tm_id,
 726                                  int result)
 727 {
 728         struct srp_internal *i = to_srp_internal(shost->transportt);
 729         return i->f->tsk_mgmt_response(shost, nexus, tm_id, result);
 730 }
 731
 732 static int srp_it_nexus_response(struct Scsi_Host *shost, u64 nexus, int result)
 733 {
 734         struct srp_internal *i = to_srp_internal(shost->transportt);
 735         return i->f->it_nexus_response(shost, nexus, result);
 736 }
 737
 738 /**
 739  * srp_attach_transport  -  instantiate SRP transport template
 740  * @ft:         SRP transport class function template
 741  */
 742 struct scsi_transport_template *
 743 srp_attach_transport(struct srp_function_template *ft)
 744 {
 745         int count;
 746         struct srp_internal *i;
 747
 748         i = kzalloc(sizeof(*i), GFP_KERNEL);
 749         if (!i)
 750                 return NULL;
 751
 752         i->t.eh_timed_out = srp_timed_out;
 753
 754         i->t.tsk_mgmt_response = srp_tsk_mgmt_response;
 755         i->t.it_nexus_response = srp_it_nexus_response;
 756
 757         i->t.host_size = sizeof(struct srp_host_attrs);
 758         i->t.host_attrs.ac.attrs = &i->host_attrs[0];
 759         i->t.host_attrs.ac.class = &srp_host_class.class;
 760         i->t.host_attrs.ac.match = srp_host_match;
 761         i->host_attrs[0] = NULL;
 762         transport_container_register(&i->t.host_attrs);
 763
 764         i->rport_attr_cont.ac.attrs = &i->rport_attrs[0];
 765         i->rport_attr_cont.ac.class = &srp_rport_class.class;
 766         i->rport_attr_cont.ac.match = srp_rport_match;
 767
 768         count = 0;
 769         i->rport_attrs[count++] = &dev_attr_port_id;
 770         i->rport_attrs[count++] = &dev_attr_roles;
 771         if (ft->has_rport_state) {
 772                 i->rport_attrs[count++] = &dev_attr_state;
 773                 i->rport_attrs[count++] = &dev_attr_fast_io_fail_tmo;
 774                 i->rport_attrs[count++] = &dev_attr_dev_loss_tmo;
 775         }
 776         if (ft->rport_delete)
 777                 i->rport_attrs[count++] = &dev_attr_delete;
 778         i->rport_attrs[count++] = NULL;
 779         BUG_ON(count > ARRAY_SIZE(i->rport_attrs));
 780
 781         transport_container_register(&i->rport_attr_cont);
 782
 783         i->f = ft;
 784
 785         return &i->t;
 786 }
 787 EXPORT_SYMBOL_GPL(srp_attach_transport);
 788
 789 /**
 790  * srp_release_transport  -  release SRP transport template instance
 791  * @t:          transport template instance
 792  */
 793 void srp_release_transport(struct scsi_transport_template *t)
 794 {
 795         struct srp_internal *i = to_srp_internal(t);
 796
 797         transport_container_unregister(&i->t.host_attrs);
 798         transport_container_unregister(&i->rport_attr_cont);
 799
 800         kfree(i);
 801 }
 802 EXPORT_SYMBOL_GPL(srp_release_transport);
 803
 804 static __init int srp_transport_init(void)
 805 {
 806         int ret;
 807
 808         ret = transport_class_register(&srp_host_class);
 809         if (ret)
 810                 return ret;
 811         ret = transport_class_register(&srp_rport_class);
 812         if (ret)
 813                 goto unregister_host_class;
 814
 815         return 0;
 816 unregister_host_class:
 817         transport_class_unregister(&srp_host_class);
 818         return ret;
 819 }
 820
 821 static void __exit srp_transport_exit(void)
 822 {
 823         transport_class_unregister(&srp_host_class);
 824         transport_class_unregister(&srp_rport_class);
 825 }
 826
 827 MODULE_AUTHOR("FUJITA Tomonori");
 828 MODULE_DESCRIPTION("SRP Transport Attributes");
 829 MODULE_LICENSE("GPL");
 830
 831 module_init(srp_transport_init);
 832 module_exit(srp_transport_exit);