kernel/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
  37 struct srp_host_attrs {
  38         atomic_t next_port_id;
  39 };
  40 #define to_srp_host_attrs(host) ((struct srp_host_attrs *)(host)->shost_data)
  41
  42 #define SRP_HOST_ATTRS 0
  43 #define SRP_RPORT_ATTRS 8
  44
  45 struct srp_internal {
  46         struct scsi_transport_template t;
  47         struct srp_function_template *f;
  48
  49         struct device_attribute *host_attrs[SRP_HOST_ATTRS + 1];
  50
  51         struct device_attribute *rport_attrs[SRP_RPORT_ATTRS + 1];
  52         struct transport_container rport_attr_cont;
  53 };
  54
  55 #define to_srp_internal(tmpl) container_of(tmpl, struct srp_internal, t)
  56
  57 #define dev_to_rport(d) container_of(d, struct srp_rport, dev)
  58 #define transport_class_to_srp_rport(dev) dev_to_rport((dev)->parent)
  59 static inline struct Scsi_Host *rport_to_shost(struct srp_rport *r)
  60 {
  61         return dev_to_shost(r->dev.parent);
  62 }
  63
  64 /**
  65  * srp_tmo_valid() - check timeout combination validity
  66  * @reconnect_delay: Reconnect delay in seconds.
  67  * @fast_io_fail_tmo: Fast I/O fail timeout in seconds.
  68  * @dev_loss_tmo: Device loss timeout in seconds.
  69  *
  70  * The combination of the timeout parameters must be such that SCSI commands
  71  * are finished in a reasonable time. Hence do not allow the fast I/O fail
  72  * timeout to exceed SCSI_DEVICE_BLOCK_MAX_TIMEOUT nor allow dev_loss_tmo to
  73  * exceed that limit if failing I/O fast has been disabled. Furthermore, these
  74  * parameters must be such that multipath can detect failed paths timely.
  75  * Hence do not allow all three parameters to be disabled simultaneously.
  76  */
  77 int srp_tmo_valid(int reconnect_delay, int fast_io_fail_tmo, int dev_loss_tmo)
  78 {
  79         if (reconnect_delay < 0 && fast_io_fail_tmo < 0 && dev_loss_tmo < 0)
  80                 return -EINVAL;
  81         if (reconnect_delay == 0)
  82                 return -EINVAL;
  83         if (fast_io_fail_tmo > SCSI_DEVICE_BLOCK_MAX_TIMEOUT)
  84                 return -EINVAL;
  85         if (fast_io_fail_tmo < 0 &&
  86             dev_loss_tmo > SCSI_DEVICE_BLOCK_MAX_TIMEOUT)
  87                 return -EINVAL;
  88         if (dev_loss_tmo >= LONG_MAX / HZ)
  89                 return -EINVAL;
  90         if (fast_io_fail_tmo >= 0 && dev_loss_tmo >= 0 &&
  91             fast_io_fail_tmo >= dev_loss_tmo)
  92                 return -EINVAL;
  93         return 0;
  94 }
  95 EXPORT_SYMBOL_GPL(srp_tmo_valid);
  96
  97 static int srp_host_setup(struct transport_container *tc, struct device *dev,
  98                           struct device *cdev)
  99 {
 100         struct Scsi_Host *shost = dev_to_shost(dev);
 101         struct srp_host_attrs *srp_host = to_srp_host_attrs(shost);
 102
 103         atomic_set(&srp_host->next_port_id, 0);
 104         return 0;
 105 }
 106
 107 static DECLARE_TRANSPORT_CLASS(srp_host_class, "srp_host", srp_host_setup,
 108                                NULL, NULL);
 109
 110 static DECLARE_TRANSPORT_CLASS(srp_rport_class, "srp_remote_ports",
 111                                NULL, NULL, NULL);
 112
 113 #define SRP_PID(p) \
 114         (p)->port_id[0], (p)->port_id[1], (p)->port_id[2], (p)->port_id[3], \
 115         (p)->port_id[4], (p)->port_id[5], (p)->port_id[6], (p)->port_id[7], \
 116         (p)->port_id[8], (p)->port_id[9], (p)->port_id[10], (p)->port_id[11], \
 117         (p)->port_id[12], (p)->port_id[13], (p)->port_id[14], (p)->port_id[15]
 118
 119 #define SRP_PID_FMT "%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:" \
 120         "%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x"
 121
 122 static ssize_t
 123 show_srp_rport_id(struct device *dev, struct device_attribute *attr,
 124                   char *buf)
 125 {
 126         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 127         return sprintf(buf, SRP_PID_FMT "\n", SRP_PID(rport));
 128 }
 129
 130 static DEVICE_ATTR(port_id, S_IRUGO, show_srp_rport_id, NULL);
 131
 132 static const struct {
 133         u32 value;
 134         char *name;
 135 } srp_rport_role_names[] = {
 136         {SRP_RPORT_ROLE_INITIATOR, "SRP Initiator"},
 137         {SRP_RPORT_ROLE_TARGET, "SRP Target"},
 138 };
 139
 140 static ssize_t
 141 show_srp_rport_roles(struct device *dev, struct device_attribute *attr,
 142                      char *buf)
 143 {
 144         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 145         int i;
 146         char *name = NULL;
 147
 148         for (i = 0; i < ARRAY_SIZE(srp_rport_role_names); i++)
 149                 if (srp_rport_role_names[i].value == rport->roles) {
 150                         name = srp_rport_role_names[i].name;
 151                         break;
 152                 }
 153         return sprintf(buf, "%s\n", name ? : "unknown");
 154 }
 155
 156 static DEVICE_ATTR(roles, S_IRUGO, show_srp_rport_roles, NULL);
 157
 158 static ssize_t store_srp_rport_delete(struct device *dev,
 159                                       struct device_attribute *attr,
 160                                       const char *buf, size_t count)
 161 {
 162         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 163         struct Scsi_Host *shost = dev_to_shost(dev);
 164         struct srp_internal *i = to_srp_internal(shost->transportt);
 165
 166         if (i->f->rport_delete) {
 167                 i->f->rport_delete(rport);
 168                 return count;
 169         } else {
 170                 return -ENOSYS;
 171         }
 172 }
 173
 174 static DEVICE_ATTR(delete, S_IWUSR, NULL, store_srp_rport_delete);
 175
 176 static ssize_t show_srp_rport_state(struct device *dev,
 177                                     struct device_attribute *attr,
 178                                     char *buf)
 179 {
 180         static const char *const state_name[] = {
 181                 [SRP_RPORT_RUNNING]     = "running",
 182                 [SRP_RPORT_BLOCKED]     = "blocked",
 183                 [SRP_RPORT_FAIL_FAST]   = "fail-fast",
 184                 [SRP_RPORT_LOST]        = "lost",
 185         };
 186         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 187         enum srp_rport_state state = rport->state;
 188
 189         return sprintf(buf, "%s\n",
 190                        (unsigned)state < ARRAY_SIZE(state_name) ?
 191                        state_name[state] : "???");
 192 }
 193
 194 static DEVICE_ATTR(state, S_IRUGO, show_srp_rport_state, NULL);
 195
 196 static ssize_t srp_show_tmo(char *buf, int tmo)
 197 {
 198         return tmo >= 0 ? sprintf(buf, "%d\n", tmo) : sprintf(buf, "off\n");
 199 }
 200
 201 static int srp_parse_tmo(int *tmo, const char *buf)
 202 {
 203         int res = 0;
 204
 205         if (strncmp(buf, "off", 3) != 0)
 206                 res = kstrtoint(buf, 0, tmo);
 207         else
 208                 *tmo = -1;
 209
 210         return res;
 211 }
 212
 213 static ssize_t show_reconnect_delay(struct device *dev,
 214                                     struct device_attribute *attr, char *buf)
 215 {
 216         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 217
 218         return srp_show_tmo(buf, rport->reconnect_delay);
 219 }
 220
 221 static ssize_t store_reconnect_delay(struct device *dev,
 222                                      struct device_attribute *attr,
 223                                      const char *buf, const size_t count)
 224 {
 225         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 226         int res, delay;
 227
 228         res = srp_parse_tmo(&delay, buf);
 229         if (res)
 230                 goto out;
 231         res = srp_tmo_valid(delay, rport->fast_io_fail_tmo,
 232                             rport->dev_loss_tmo);
 233         if (res)
 234                 goto out;
 235
 236         if (rport->reconnect_delay <= 0 && delay > 0 &&
 237             rport->state != SRP_RPORT_RUNNING) {
 238                 queue_delayed_work(system_long_wq, &rport->reconnect_work,
 239                                    delay * HZ);
 240         } else if (delay <= 0) {
 241                 cancel_delayed_work(&rport->reconnect_work);
 242         }
 243         rport->reconnect_delay = delay;
 244         res = count;
 245
 246 out:
 247         return res;
 248 }
 249
 250 static DEVICE_ATTR(reconnect_delay, S_IRUGO | S_IWUSR, show_reconnect_delay,
 251                    store_reconnect_delay);
 252
 253 static ssize_t show_failed_reconnects(struct device *dev,
 254                                       struct device_attribute *attr, char *buf)
 255 {
 256         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 257
 258         return sprintf(buf, "%d\n", rport->failed_reconnects);
 259 }
 260
 261 static DEVICE_ATTR(failed_reconnects, S_IRUGO, show_failed_reconnects, NULL);
 262
 263 static ssize_t show_srp_rport_fast_io_fail_tmo(struct device *dev,
 264                                                struct device_attribute *attr,
 265                                                char *buf)
 266 {
 267         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 268
 269         return srp_show_tmo(buf, rport->fast_io_fail_tmo);
 270 }
 271
 272 static ssize_t store_srp_rport_fast_io_fail_tmo(struct device *dev,
 273                                                 struct device_attribute *attr,
 274                                                 const char *buf, size_t count)
 275 {
 276         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 277         int res;
 278         int fast_io_fail_tmo;
 279
 280         res = srp_parse_tmo(&fast_io_fail_tmo, buf);
 281         if (res)
 282                 goto out;
 283         res = srp_tmo_valid(rport->reconnect_delay, fast_io_fail_tmo,
 284                             rport->dev_loss_tmo);
 285         if (res)
 286                 goto out;
 287         rport->fast_io_fail_tmo = fast_io_fail_tmo;
 288         res = count;
 289
 290 out:
 291         return res;
 292 }
 293
 294 static DEVICE_ATTR(fast_io_fail_tmo, S_IRUGO | S_IWUSR,
 295                    show_srp_rport_fast_io_fail_tmo,
 296                    store_srp_rport_fast_io_fail_tmo);
 297
 298 static ssize_t show_srp_rport_dev_loss_tmo(struct device *dev,
 299                                            struct device_attribute *attr,
 300                                            char *buf)
 301 {
 302         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 303
 304         return srp_show_tmo(buf, rport->dev_loss_tmo);
 305 }
 306
 307 static ssize_t store_srp_rport_dev_loss_tmo(struct device *dev,
 308                                             struct device_attribute *attr,
 309                                             const char *buf, size_t count)
 310 {
 311         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 312         int res;
 313         int dev_loss_tmo;
 314
 315         res = srp_parse_tmo(&dev_loss_tmo, buf);
 316         if (res)
 317                 goto out;
 318         res = srp_tmo_valid(rport->reconnect_delay, rport->fast_io_fail_tmo,
 319                             dev_loss_tmo);
 320         if (res)
 321                 goto out;
 322         rport->dev_loss_tmo = dev_loss_tmo;
 323         res = count;
 324
 325 out:
 326         return res;
 327 }
 328
 329 static DEVICE_ATTR(dev_loss_tmo, S_IRUGO | S_IWUSR,
 330                    show_srp_rport_dev_loss_tmo,
 331                    store_srp_rport_dev_loss_tmo);
 332
 333 static int srp_rport_set_state(struct srp_rport *rport,
 334                                enum srp_rport_state new_state)
 335 {
 336         enum srp_rport_state old_state = rport->state;
 337
 338         lockdep_assert_held(&rport->mutex);
 339
 340         switch (new_state) {
 341         case SRP_RPORT_RUNNING:
 342                 switch (old_state) {
 343                 case SRP_RPORT_LOST:
 344                         goto invalid;
 345                 default:
 346                         break;
 347                 }
 348                 break;
 349         case SRP_RPORT_BLOCKED:
 350                 switch (old_state) {
 351                 case SRP_RPORT_RUNNING:
 352                         break;
 353                 default:
 354                         goto invalid;
 355                 }
 356                 break;
 357         case SRP_RPORT_FAIL_FAST:
 358                 switch (old_state) {
 359                 case SRP_RPORT_LOST:
 360                         goto invalid;
 361                 default:
 362                         break;
 363                 }
 364                 break;
 365         case SRP_RPORT_LOST:
 366                 break;
 367         }
 368         rport->state = new_state;
 369         return 0;
 370
 371 invalid:
 372         return -EINVAL;
 373 }
 374
 375 /**
 376  * srp_reconnect_work() - reconnect and schedule a new attempt if necessary
 377  * @work: Work structure used for scheduling this operation.
 378  */
 379 static void srp_reconnect_work(struct work_struct *work)
 380 {
 381         struct srp_rport *rport = container_of(to_delayed_work(work),
 382                                         struct srp_rport, reconnect_work);
 383         struct Scsi_Host *shost = rport_to_shost(rport);
 384         int delay, res;
 385
 386         res = srp_reconnect_rport(rport);
 387         if (res != 0) {
 388                 shost_printk(KERN_ERR, shost,
 389                              "reconnect attempt %d failed (%d)\n",
 390                              ++rport->failed_reconnects, res);
 391                 delay = rport->reconnect_delay *
 392                         min(100, max(1, rport->failed_reconnects - 10));
 393                 if (delay > 0)
 394                         queue_delayed_work(system_long_wq,
 395                                            &rport->reconnect_work, delay * HZ);
 396         }
 397 }
 398
 399 /**
 400  * scsi_request_fn_active() - number of kernel threads inside scsi_request_fn()
 401  * @shost: SCSI host for which to count the number of scsi_request_fn() callers.
 402  *
 403  * To do: add support for scsi-mq in this function.
 404  */
 405 static int scsi_request_fn_active(struct Scsi_Host *shost)
 406 {
 407         struct scsi_device *sdev;
 408         struct request_queue *q;
 409         int request_fn_active = 0;
 410
 411         shost_for_each_device(sdev, shost) {
 412                 q = sdev->request_queue;
 413
 414                 spin_lock_irq(q->queue_lock);
 415                 request_fn_active += q->request_fn_active;
 416                 spin_unlock_irq(q->queue_lock);
 417         }
 418
 419         return request_fn_active;
 420 }
 421
 422 /* Wait until ongoing shost->hostt->queuecommand() calls have finished. */
 423 static void srp_wait_for_queuecommand(struct Scsi_Host *shost)
 424 {
 425         while (scsi_request_fn_active(shost))
 426                 msleep(20);
 427 }
 428
 429 static void __rport_fail_io_fast(struct srp_rport *rport)
 430 {
 431         struct Scsi_Host *shost = rport_to_shost(rport);
 432         struct srp_internal *i;
 433
 434         lockdep_assert_held(&rport->mutex);
 435
 436         if (srp_rport_set_state(rport, SRP_RPORT_FAIL_FAST))
 437                 return;
 438         scsi_target_unblock(rport->dev.parent, SDEV_TRANSPORT_OFFLINE);
 439
 440         /* Involve the LLD if possible to terminate all I/O on the rport. */
 441         i = to_srp_internal(shost->transportt);
 442         if (i->f->terminate_rport_io) {
 443                 srp_wait_for_queuecommand(shost);
 444                 i->f->terminate_rport_io(rport);
 445         }
 446 }
 447
 448 /**
 449  * rport_fast_io_fail_timedout() - fast I/O failure timeout handler
 450  * @work: Work structure used for scheduling this operation.
 451  */
 452 static void rport_fast_io_fail_timedout(struct work_struct *work)
 453 {
 454         struct srp_rport *rport = container_of(to_delayed_work(work),
 455                                         struct srp_rport, fast_io_fail_work);
 456         struct Scsi_Host *shost = rport_to_shost(rport);
 457
 458         pr_info("fast_io_fail_tmo expired for SRP %s / %s.\n",
 459                 dev_name(&rport->dev), dev_name(&shost->shost_gendev));
 460
 461         mutex_lock(&rport->mutex);
 462         if (rport->state == SRP_RPORT_BLOCKED)
 463                 __rport_fail_io_fast(rport);
 464         mutex_unlock(&rport->mutex);
 465 }
 466
 467 /**
 468  * rport_dev_loss_timedout() - device loss timeout handler
 469  * @work: Work structure used for scheduling this operation.
 470  */
 471 static void rport_dev_loss_timedout(struct work_struct *work)
 472 {
 473         struct srp_rport *rport = container_of(to_delayed_work(work),
 474                                         struct srp_rport, dev_loss_work);
 475         struct Scsi_Host *shost = rport_to_shost(rport);
 476         struct srp_internal *i = to_srp_internal(shost->transportt);
 477
 478         pr_info("dev_loss_tmo expired for SRP %s / %s.\n",
 479                 dev_name(&rport->dev), dev_name(&shost->shost_gendev));
 480
 481         mutex_lock(&rport->mutex);
 482         WARN_ON(srp_rport_set_state(rport, SRP_RPORT_LOST) != 0);
 483         scsi_target_unblock(rport->dev.parent, SDEV_TRANSPORT_OFFLINE);
 484         mutex_unlock(&rport->mutex);
 485
 486         i->f->rport_delete(rport);
 487 }
 488
 489 static void __srp_start_tl_fail_timers(struct srp_rport *rport)
 490 {
 491         struct Scsi_Host *shost = rport_to_shost(rport);
 492         int delay, fast_io_fail_tmo, dev_loss_tmo;
 493
 494         lockdep_assert_held(&rport->mutex);
 495
 496         delay = rport->reconnect_delay;
 497         fast_io_fail_tmo = rport->fast_io_fail_tmo;
 498         dev_loss_tmo = rport->dev_loss_tmo;
 499         pr_debug("%s current state: %d\n", dev_name(&shost->shost_gendev),
 500                  rport->state);
 501
 502         if (rport->state == SRP_RPORT_LOST)
 503                 return;
 504         if (delay > 0)
 505                 queue_delayed_work(system_long_wq, &rport->reconnect_work,
 506                                    1UL * delay * HZ);
 507         if ((fast_io_fail_tmo >= 0 || dev_loss_tmo >= 0) &&
 508             srp_rport_set_state(rport, SRP_RPORT_BLOCKED) == 0) {
 509                 pr_debug("%s new state: %d\n", dev_name(&shost->shost_gendev),
 510                          rport->state);
 511                 scsi_target_block(&shost->shost_gendev);
 512                 if (fast_io_fail_tmo >= 0)
 513                         queue_delayed_work(system_long_wq,
 514                                            &rport->fast_io_fail_work,
 515                                            1UL * fast_io_fail_tmo * HZ);
 516                 if (dev_loss_tmo >= 0)
 517                         queue_delayed_work(system_long_wq,
 518                                            &rport->dev_loss_work,
 519                                            1UL * dev_loss_tmo * HZ);
 520         }
 521 }
 522
 523 /**
 524  * srp_start_tl_fail_timers() - start the transport layer failure timers
 525  * @rport: SRP target port.
 526  *
 527  * Start the transport layer fast I/O failure and device loss timers. Do not
 528  * modify a timer that was already started.
 529  */
 530 void srp_start_tl_fail_timers(struct srp_rport *rport)
 531 {
 532         mutex_lock(&rport->mutex);
 533         __srp_start_tl_fail_timers(rport);
 534         mutex_unlock(&rport->mutex);
 535 }
 536 EXPORT_SYMBOL(srp_start_tl_fail_timers);
 537
 538 /**
 539  * srp_reconnect_rport() - reconnect to an SRP target port
 540  * @rport: SRP target port.
 541  *
 542  * Blocks SCSI command queueing before invoking reconnect() such that
 543  * queuecommand() won't be invoked concurrently with reconnect() from outside
 544  * the SCSI EH. This is important since a reconnect() implementation may
 545  * reallocate resources needed by queuecommand().
 546  *
 547  * Notes:
 548  * - This function neither waits until outstanding requests have finished nor
 549  *   tries to abort these. It is the responsibility of the reconnect()
 550  *   function to finish outstanding commands before reconnecting to the target
 551  *   port.
 552  * - It is the responsibility of the caller to ensure that the resources
 553  *   reallocated by the reconnect() function won't be used while this function
 554  *   is in progress. One possible strategy is to invoke this function from
 555  *   the context of the SCSI EH thread only. Another possible strategy is to
 556  *   lock the rport mutex inside each SCSI LLD callback that can be invoked by
 557  *   the SCSI EH (the scsi_host_template.eh_*() functions and also the
 558  *   scsi_host_template.queuecommand() function).
 559  */
 560 int srp_reconnect_rport(struct srp_rport *rport)
 561 {
 562         struct Scsi_Host *shost = rport_to_shost(rport);
 563         struct srp_internal *i = to_srp_internal(shost->transportt);
 564         struct scsi_device *sdev;
 565         int res;
 566
 567         pr_debug("SCSI host %s\n", dev_name(&shost->shost_gendev));
 568
 569         res = mutex_lock_interruptible(&rport->mutex);
 570         if (res)
 571                 goto out;
 572         scsi_target_block(&shost->shost_gendev);
 573         srp_wait_for_queuecommand(shost);
 574         res = rport->state != SRP_RPORT_LOST ? i->f->reconnect(rport) : -ENODEV;
 575         pr_debug("%s (state %d): transport.reconnect() returned %d\n",
 576                  dev_name(&shost->shost_gendev), rport->state, res);
 577         if (res == 0) {
 578                 cancel_delayed_work(&rport->fast_io_fail_work);
 579                 cancel_delayed_work(&rport->dev_loss_work);
 580
 581                 rport->failed_reconnects = 0;
 582                 srp_rport_set_state(rport, SRP_RPORT_RUNNING);
 583                 scsi_target_unblock(&shost->shost_gendev, SDEV_RUNNING);
 584                 /*
 585                  * If the SCSI error handler has offlined one or more devices,
 586                  * invoking scsi_target_unblock() won't change the state of
 587                  * these devices into running so do that explicitly.
 588                  */
 589                 spin_lock_irq(shost->host_lock);
 590                 __shost_for_each_device(sdev, shost)
 591                         if (sdev->sdev_state == SDEV_OFFLINE)
 592                                 sdev->sdev_state = SDEV_RUNNING;
 593                 spin_unlock_irq(shost->host_lock);
 594         } else if (rport->state == SRP_RPORT_RUNNING) {
 595                 /*
 596                  * srp_reconnect_rport() has been invoked with fast_io_fail
 597                  * and dev_loss off. Mark the port as failed and start the TL
 598                  * failure timers if these had not yet been started.
 599                  */
 600                 __rport_fail_io_fast(rport);
 601                 scsi_target_unblock(&shost->shost_gendev,
 602                                     SDEV_TRANSPORT_OFFLINE);
 603                 __srp_start_tl_fail_timers(rport);
 604         } else if (rport->state != SRP_RPORT_BLOCKED) {
 605                 scsi_target_unblock(&shost->shost_gendev,
 606                                     SDEV_TRANSPORT_OFFLINE);
 607         }
 608         mutex_unlock(&rport->mutex);
 609
 610 out:
 611         return res;
 612 }
 613 EXPORT_SYMBOL(srp_reconnect_rport);
 614
 615 /**
 616  * srp_timed_out() - SRP transport intercept of the SCSI timeout EH
 617  * @scmd: SCSI command.
 618  *
 619  * If a timeout occurs while an rport is in the blocked state, ask the SCSI
 620  * EH to continue waiting (BLK_EH_RESET_TIMER). Otherwise let the SCSI core
 621  * handle the timeout (BLK_EH_NOT_HANDLED).
 622  *
 623  * Note: This function is called from soft-IRQ context and with the request
 624  * queue lock held.
 625  */
 626 static enum blk_eh_timer_return srp_timed_out(struct scsi_cmnd *scmd)
 627 {
 628         struct scsi_device *sdev = scmd->device;
 629         struct Scsi_Host *shost = sdev->host;
 630         struct srp_internal *i = to_srp_internal(shost->transportt);
 631
 632         pr_debug("timeout for sdev %s\n", dev_name(&sdev->sdev_gendev));
 633         return i->f->reset_timer_if_blocked && scsi_device_blocked(sdev) ?
 634                 BLK_EH_RESET_TIMER : BLK_EH_NOT_HANDLED;
 635 }
 636
 637 static void srp_rport_release(struct device *dev)
 638 {
 639         struct srp_rport *rport = dev_to_rport(dev);
 640
 641         put_device(dev->parent);
 642         kfree(rport);
 643 }
 644
 645 static int scsi_is_srp_rport(const struct device *dev)
 646 {
 647         return dev->release == srp_rport_release;
 648 }
 649
 650 static int srp_rport_match(struct attribute_container *cont,
 651                            struct device *dev)
 652 {
 653         struct Scsi_Host *shost;
 654         struct srp_internal *i;
 655
 656         if (!scsi_is_srp_rport(dev))
 657                 return 0;
 658
 659         shost = dev_to_shost(dev->parent);
 660         if (!shost->transportt)
 661                 return 0;
 662         if (shost->transportt->host_attrs.ac.class != &srp_host_class.class)
 663                 return 0;
 664
 665         i = to_srp_internal(shost->transportt);
 666         return &i->rport_attr_cont.ac == cont;
 667 }
 668
 669 static int srp_host_match(struct attribute_container *cont, struct device *dev)
 670 {
 671         struct Scsi_Host *shost;
 672         struct srp_internal *i;
 673
 674         if (!scsi_is_host_device(dev))
 675                 return 0;
 676
 677         shost = dev_to_shost(dev);
 678         if (!shost->transportt)
 679                 return 0;
 680         if (shost->transportt->host_attrs.ac.class != &srp_host_class.class)
 681                 return 0;
 682
 683         i = to_srp_internal(shost->transportt);
 684         return &i->t.host_attrs.ac == cont;
 685 }
 686
 687 /**
 688  * srp_rport_get() - increment rport reference count
 689  * @rport: SRP target port.
 690  */
 691 void srp_rport_get(struct srp_rport *rport)
 692 {
 693         get_device(&rport->dev);
 694 }
 695 EXPORT_SYMBOL(srp_rport_get);
 696
 697 /**
 698  * srp_rport_put() - decrement rport reference count
 699  * @rport: SRP target port.
 700  */
 701 void srp_rport_put(struct srp_rport *rport)
 702 {
 703         put_device(&rport->dev);
 704 }
 705 EXPORT_SYMBOL(srp_rport_put);
 706
 707 /**
 708  * srp_rport_add - add a SRP remote port to the device hierarchy
 709  * @shost:      scsi host the remote port is connected to.
 710  * @ids:        The port id for the remote port.
 711  *
 712  * Publishes a port to the rest of the system.
 713  */
 714 struct srp_rport *srp_rport_add(struct Scsi_Host *shost,
 715                                 struct srp_rport_identifiers *ids)
 716 {
 717         struct srp_rport *rport;
 718         struct device *parent = &shost->shost_gendev;
 719         struct srp_internal *i = to_srp_internal(shost->transportt);
 720         int id, ret;
 721
 722         rport = kzalloc(sizeof(*rport), GFP_KERNEL);
 723         if (!rport)
 724                 return ERR_PTR(-ENOMEM);
 725
 726         mutex_init(&rport->mutex);
 727
 728         device_initialize(&rport->dev);
 729
 730         rport->dev.parent = get_device(parent);
 731         rport->dev.release = srp_rport_release;
 732
 733         memcpy(rport->port_id, ids->port_id, sizeof(rport->port_id));
 734         rport->roles = ids->roles;
 735
 736         if (i->f->reconnect)
 737                 rport->reconnect_delay = i->f->reconnect_delay ?
 738                         *i->f->reconnect_delay : 10;
 739         INIT_DELAYED_WORK(&rport->reconnect_work, srp_reconnect_work);
 740         rport->fast_io_fail_tmo = i->f->fast_io_fail_tmo ?
 741                 *i->f->fast_io_fail_tmo : 15;
 742         rport->dev_loss_tmo = i->f->dev_loss_tmo ? *i->f->dev_loss_tmo : 60;
 743         INIT_DELAYED_WORK(&rport->fast_io_fail_work,
 744                           rport_fast_io_fail_timedout);
 745         INIT_DELAYED_WORK(&rport->dev_loss_work, rport_dev_loss_timedout);
 746
 747         id = atomic_inc_return(&to_srp_host_attrs(shost)->next_port_id);
 748         dev_set_name(&rport->dev, "port-%d:%d", shost->host_no, id);
 749
 750         transport_setup_device(&rport->dev);
 751
 752         ret = device_add(&rport->dev);
 753         if (ret) {
 754                 transport_destroy_device(&rport->dev);
 755                 put_device(&rport->dev);
 756                 return ERR_PTR(ret);
 757         }
 758
 759         transport_add_device(&rport->dev);
 760         transport_configure_device(&rport->dev);
 761
 762         return rport;
 763 }
 764 EXPORT_SYMBOL_GPL(srp_rport_add);
 765
 766 /**
 767  * srp_rport_del  -  remove a SRP remote port
 768  * @rport:      SRP remote port to remove
 769  *
 770  * Removes the specified SRP remote port.
 771  */
 772 void srp_rport_del(struct srp_rport *rport)
 773 {
 774         struct device *dev = &rport->dev;
 775
 776         transport_remove_device(dev);
 777         device_del(dev);
 778         transport_destroy_device(dev);
 779
 780         put_device(dev);
 781 }
 782 EXPORT_SYMBOL_GPL(srp_rport_del);
 783
 784 static int do_srp_rport_del(struct device *dev, void *data)
 785 {
 786         if (scsi_is_srp_rport(dev))
 787                 srp_rport_del(dev_to_rport(dev));
 788         return 0;
 789 }
 790
 791 /**
 792  * srp_remove_host  -  tear down a Scsi_Host's SRP data structures
 793  * @shost:      Scsi Host that is torn down
 794  *
 795  * Removes all SRP remote ports for a given Scsi_Host.
 796  * Must be called just before scsi_remove_host for SRP HBAs.
 797  */
 798 void srp_remove_host(struct Scsi_Host *shost)
 799 {
 800         device_for_each_child(&shost->shost_gendev, NULL, do_srp_rport_del);
 801 }
 802 EXPORT_SYMBOL_GPL(srp_remove_host);
 803
 804 /**
 805  * srp_stop_rport_timers - stop the transport layer recovery timers
 806  * @rport: SRP remote port for which to stop the timers.
 807  *
 808  * Must be called after srp_remove_host() and scsi_remove_host(). The caller
 809  * must hold a reference on the rport (rport->dev) and on the SCSI host
 810  * (rport->dev.parent).
 811  */
 812 void srp_stop_rport_timers(struct srp_rport *rport)
 813 {
 814         mutex_lock(&rport->mutex);
 815         if (rport->state == SRP_RPORT_BLOCKED)
 816                 __rport_fail_io_fast(rport);
 817         srp_rport_set_state(rport, SRP_RPORT_LOST);
 818         mutex_unlock(&rport->mutex);
 819
 820         cancel_delayed_work_sync(&rport->reconnect_work);
 821         cancel_delayed_work_sync(&rport->fast_io_fail_work);
 822         cancel_delayed_work_sync(&rport->dev_loss_work);
 823 }
 824 EXPORT_SYMBOL_GPL(srp_stop_rport_timers);
 825
 826 static int srp_tsk_mgmt_response(struct Scsi_Host *shost, u64 nexus, u64 tm_id,
 827                                  int result)
 828 {
 829         struct srp_internal *i = to_srp_internal(shost->transportt);
 830         return i->f->tsk_mgmt_response(shost, nexus, tm_id, result);
 831 }
 832
 833 static int srp_it_nexus_response(struct Scsi_Host *shost, u64 nexus, int result)
 834 {
 835         struct srp_internal *i = to_srp_internal(shost->transportt);
 836         return i->f->it_nexus_response(shost, nexus, result);
 837 }
 838
 839 /**
 840  * srp_attach_transport  -  instantiate SRP transport template
 841  * @ft:         SRP transport class function template
 842  */
 843 struct scsi_transport_template *
 844 srp_attach_transport(struct srp_function_template *ft)
 845 {
 846         int count;
 847         struct srp_internal *i;
 848
 849         i = kzalloc(sizeof(*i), GFP_KERNEL);
 850         if (!i)
 851                 return NULL;
 852
 853         i->t.eh_timed_out = srp_timed_out;
 854
 855         i->t.tsk_mgmt_response = srp_tsk_mgmt_response;
 856         i->t.it_nexus_response = srp_it_nexus_response;
 857
 858         i->t.host_size = sizeof(struct srp_host_attrs);
 859         i->t.host_attrs.ac.attrs = &i->host_attrs[0];
 860         i->t.host_attrs.ac.class = &srp_host_class.class;
 861         i->t.host_attrs.ac.match = srp_host_match;
 862         i->host_attrs[0] = NULL;
 863         transport_container_register(&i->t.host_attrs);
 864
 865         i->rport_attr_cont.ac.attrs = &i->rport_attrs[0];
 866         i->rport_attr_cont.ac.class = &srp_rport_class.class;
 867         i->rport_attr_cont.ac.match = srp_rport_match;
 868
 869         count = 0;
 870         i->rport_attrs[count++] = &dev_attr_port_id;
 871         i->rport_attrs[count++] = &dev_attr_roles;
 872         if (ft->has_rport_state) {
 873                 i->rport_attrs[count++] = &dev_attr_state;
 874                 i->rport_attrs[count++] = &dev_attr_fast_io_fail_tmo;
 875                 i->rport_attrs[count++] = &dev_attr_dev_loss_tmo;
 876         }
 877         if (ft->reconnect) {
 878                 i->rport_attrs[count++] = &dev_attr_reconnect_delay;
 879                 i->rport_attrs[count++] = &dev_attr_failed_reconnects;
 880         }
 881         if (ft->rport_delete)
 882                 i->rport_attrs[count++] = &dev_attr_delete;
 883         i->rport_attrs[count++] = NULL;
 884         BUG_ON(count > ARRAY_SIZE(i->rport_attrs));
 885
 886         transport_container_register(&i->rport_attr_cont);
 887
 888         i->f = ft;
 889
 890         return &i->t;
 891 }
 892 EXPORT_SYMBOL_GPL(srp_attach_transport);
 893
 894 /**
 895  * srp_release_transport  -  release SRP transport template instance
 896  * @t:          transport template instance
 897  */
 898 void srp_release_transport(struct scsi_transport_template *t)
 899 {
 900         struct srp_internal *i = to_srp_internal(t);
 901
 902         transport_container_unregister(&i->t.host_attrs);
 903         transport_container_unregister(&i->rport_attr_cont);
 904
 905         kfree(i);
 906 }
 907 EXPORT_SYMBOL_GPL(srp_release_transport);
 908
 909 static __init int srp_transport_init(void)
 910 {
 911         int ret;
 912
 913         ret = transport_class_register(&srp_host_class);
 914         if (ret)
 915                 return ret;
 916         ret = transport_class_register(&srp_rport_class);
 917         if (ret)
 918                 goto unregister_host_class;
 919
 920         return 0;
 921 unregister_host_class:
 922         transport_class_unregister(&srp_host_class);
 923         return ret;
 924 }
 925
 926 static void __exit srp_transport_exit(void)
 927 {
 928         transport_class_unregister(&srp_host_class);
 929         transport_class_unregister(&srp_rport_class);
 930 }
 931
 932 MODULE_AUTHOR("FUJITA Tomonori");
 933 MODULE_DESCRIPTION("SRP Transport Attributes");
 934 MODULE_LICENSE("GPL");
 935
 936 module_init(srp_transport_init);
 937 module_exit(srp_transport_exit);