drivers/scsi/scsi_transport_srp.c

   1 /*
   2  * SCSI RDMA (SRP) transport class
   3  *
   4  * Copyright (C) 2007 FUJITA Tomonori <[email protected]>
   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 static void __rport_fail_io_fast(struct srp_rport *rport)
 400 {
 401         struct Scsi_Host *shost = rport_to_shost(rport);
 402         struct srp_internal *i;
 403
 404         lockdep_assert_held(&rport->mutex);
 405
 406         if (srp_rport_set_state(rport, SRP_RPORT_FAIL_FAST))
 407                 return;
 408         scsi_target_unblock(rport->dev.parent, SDEV_TRANSPORT_OFFLINE);
 409
 410         /* Involve the LLD if possible to terminate all I/O on the rport. */
 411         i = to_srp_internal(shost->transportt);
 412         if (i->f->terminate_rport_io)
 413                 i->f->terminate_rport_io(rport);
 414 }
 415
 416 /**
 417  * rport_fast_io_fail_timedout() - fast I/O failure timeout handler
 418  * @work: Work structure used for scheduling this operation.
 419  */
 420 static void rport_fast_io_fail_timedout(struct work_struct *work)
 421 {
 422         struct srp_rport *rport = container_of(to_delayed_work(work),
 423                                         struct srp_rport, fast_io_fail_work);
 424         struct Scsi_Host *shost = rport_to_shost(rport);
 425
 426         pr_info("fast_io_fail_tmo expired for SRP %s / %s.\n",
 427                 dev_name(&rport->dev), dev_name(&shost->shost_gendev));
 428
 429         mutex_lock(&rport->mutex);
 430         if (rport->state == SRP_RPORT_BLOCKED)
 431                 __rport_fail_io_fast(rport);
 432         mutex_unlock(&rport->mutex);
 433 }
 434
 435 /**
 436  * rport_dev_loss_timedout() - device loss timeout handler
 437  * @work: Work structure used for scheduling this operation.
 438  */
 439 static void rport_dev_loss_timedout(struct work_struct *work)
 440 {
 441         struct srp_rport *rport = container_of(to_delayed_work(work),
 442                                         struct srp_rport, dev_loss_work);
 443         struct Scsi_Host *shost = rport_to_shost(rport);
 444         struct srp_internal *i = to_srp_internal(shost->transportt);
 445
 446         pr_info("dev_loss_tmo expired for SRP %s / %s.\n",
 447                 dev_name(&rport->dev), dev_name(&shost->shost_gendev));
 448
 449         mutex_lock(&rport->mutex);
 450         WARN_ON(srp_rport_set_state(rport, SRP_RPORT_LOST) != 0);
 451         scsi_target_unblock(rport->dev.parent, SDEV_TRANSPORT_OFFLINE);
 452         mutex_unlock(&rport->mutex);
 453
 454         i->f->rport_delete(rport);
 455 }
 456
 457 static void __srp_start_tl_fail_timers(struct srp_rport *rport)
 458 {
 459         struct Scsi_Host *shost = rport_to_shost(rport);
 460         int delay, fast_io_fail_tmo, dev_loss_tmo;
 461
 462         lockdep_assert_held(&rport->mutex);
 463
 464         delay = rport->reconnect_delay;
 465         fast_io_fail_tmo = rport->fast_io_fail_tmo;
 466         dev_loss_tmo = rport->dev_loss_tmo;
 467         pr_debug("%s current state: %d\n", dev_name(&shost->shost_gendev),
 468                  rport->state);
 469
 470         if (rport->state == SRP_RPORT_LOST)
 471                 return;
 472         if (delay > 0)
 473                 queue_delayed_work(system_long_wq, &rport->reconnect_work,
 474                                    1UL * delay * HZ);
 475         if ((fast_io_fail_tmo >= 0 || dev_loss_tmo >= 0) &&
 476             srp_rport_set_state(rport, SRP_RPORT_BLOCKED) == 0) {
 477                 pr_debug("%s new state: %d\n", dev_name(&shost->shost_gendev),
 478                          rport->state);
 479                 scsi_target_block(&shost->shost_gendev);
 480                 if (fast_io_fail_tmo >= 0)
 481                         queue_delayed_work(system_long_wq,
 482                                            &rport->fast_io_fail_work,
 483                                            1UL * fast_io_fail_tmo * HZ);
 484                 if (dev_loss_tmo >= 0)
 485                         queue_delayed_work(system_long_wq,
 486                                            &rport->dev_loss_work,
 487                                            1UL * dev_loss_tmo * HZ);
 488         }
 489 }
 490
 491 /**
 492  * srp_start_tl_fail_timers() - start the transport layer failure timers
 493  * @rport: SRP target port.
 494  *
 495  * Start the transport layer fast I/O failure and device loss timers. Do not
 496  * modify a timer that was already started.
 497  */
 498 void srp_start_tl_fail_timers(struct srp_rport *rport)
 499 {
 500         mutex_lock(&rport->mutex);
 501         __srp_start_tl_fail_timers(rport);
 502         mutex_unlock(&rport->mutex);
 503 }
 504 EXPORT_SYMBOL(srp_start_tl_fail_timers);
 505
 506 /**
 507  * scsi_request_fn_active() - number of kernel threads inside scsi_request_fn()
 508  * @shost: SCSI host for which to count the number of scsi_request_fn() callers.
 509  */
 510 static int scsi_request_fn_active(struct Scsi_Host *shost)
 511 {
 512         struct scsi_device *sdev;
 513         struct request_queue *q;
 514         int request_fn_active = 0;
 515
 516         shost_for_each_device(sdev, shost) {
 517                 q = sdev->request_queue;
 518
 519                 spin_lock_irq(q->queue_lock);
 520                 request_fn_active += q->request_fn_active;
 521                 spin_unlock_irq(q->queue_lock);
 522         }
 523
 524         return request_fn_active;
 525 }
 526
 527 /**
 528  * srp_reconnect_rport() - reconnect to an SRP target port
 529  * @rport: SRP target port.
 530  *
 531  * Blocks SCSI command queueing before invoking reconnect() such that
 532  * queuecommand() won't be invoked concurrently with reconnect() from outside
 533  * the SCSI EH. This is important since a reconnect() implementation may
 534  * reallocate resources needed by queuecommand().
 535  *
 536  * Notes:
 537  * - This function neither waits until outstanding requests have finished nor
 538  *   tries to abort these. It is the responsibility of the reconnect()
 539  *   function to finish outstanding commands before reconnecting to the target
 540  *   port.
 541  * - It is the responsibility of the caller to ensure that the resources
 542  *   reallocated by the reconnect() function won't be used while this function
 543  *   is in progress. One possible strategy is to invoke this function from
 544  *   the context of the SCSI EH thread only. Another possible strategy is to
 545  *   lock the rport mutex inside each SCSI LLD callback that can be invoked by
 546  *   the SCSI EH (the scsi_host_template.eh_*() functions and also the
 547  *   scsi_host_template.queuecommand() function).
 548  */
 549 int srp_reconnect_rport(struct srp_rport *rport)
 550 {
 551         struct Scsi_Host *shost = rport_to_shost(rport);
 552         struct srp_internal *i = to_srp_internal(shost->transportt);
 553         struct scsi_device *sdev;
 554         int res;
 555
 556         pr_debug("SCSI host %s\n", dev_name(&shost->shost_gendev));
 557
 558         res = mutex_lock_interruptible(&rport->mutex);
 559         if (res)
 560                 goto out;
 561         scsi_target_block(&shost->shost_gendev);
 562         while (scsi_request_fn_active(shost))
 563                 msleep(20);
 564         res = rport->state != SRP_RPORT_LOST ? i->f->reconnect(rport) : -ENODEV;
 565         pr_debug("%s (state %d): transport.reconnect() returned %d\n",
 566                  dev_name(&shost->shost_gendev), rport->state, res);
 567         if (res == 0) {
 568                 cancel_delayed_work(&rport->fast_io_fail_work);
 569                 cancel_delayed_work(&rport->dev_loss_work);
 570
 571                 rport->failed_reconnects = 0;
 572                 srp_rport_set_state(rport, SRP_RPORT_RUNNING);
 573                 scsi_target_unblock(&shost->shost_gendev, SDEV_RUNNING);
 574                 /*
 575                  * If the SCSI error handler has offlined one or more devices,
 576                  * invoking scsi_target_unblock() won't change the state of
 577                  * these devices into running so do that explicitly.
 578                  */
 579                 spin_lock_irq(shost->host_lock);
 580                 __shost_for_each_device(sdev, shost)
 581                         if (sdev->sdev_state == SDEV_OFFLINE)
 582                                 sdev->sdev_state = SDEV_RUNNING;
 583                 spin_unlock_irq(shost->host_lock);
 584         } else if (rport->state == SRP_RPORT_RUNNING) {
 585                 /*
 586                  * srp_reconnect_rport() has been invoked with fast_io_fail
 587                  * and dev_loss off. Mark the port as failed and start the TL
 588                  * failure timers if these had not yet been started.
 589                  */
 590                 __rport_fail_io_fast(rport);
 591                 scsi_target_unblock(&shost->shost_gendev,
 592                                     SDEV_TRANSPORT_OFFLINE);
 593                 __srp_start_tl_fail_timers(rport);
 594         } else if (rport->state != SRP_RPORT_BLOCKED) {
 595                 scsi_target_unblock(&shost->shost_gendev,
 596                                     SDEV_TRANSPORT_OFFLINE);
 597         }
 598         mutex_unlock(&rport->mutex);
 599
 600 out:
 601         return res;
 602 }
 603 EXPORT_SYMBOL(srp_reconnect_rport);
 604
 605 /**
 606  * srp_timed_out() - SRP transport intercept of the SCSI timeout EH
 607  * @scmd: SCSI command.
 608  *
 609  * If a timeout occurs while an rport is in the blocked state, ask the SCSI
 610  * EH to continue waiting (BLK_EH_RESET_TIMER). Otherwise let the SCSI core
 611  * handle the timeout (BLK_EH_NOT_HANDLED).
 612  *
 613  * Note: This function is called from soft-IRQ context and with the request
 614  * queue lock held.
 615  */
 616 static enum blk_eh_timer_return srp_timed_out(struct scsi_cmnd *scmd)
 617 {
 618         struct scsi_device *sdev = scmd->device;
 619         struct Scsi_Host *shost = sdev->host;
 620         struct srp_internal *i = to_srp_internal(shost->transportt);
 621
 622         pr_debug("timeout for sdev %s\n", dev_name(&sdev->sdev_gendev));
 623         return i->f->reset_timer_if_blocked && scsi_device_blocked(sdev) ?
 624                 BLK_EH_RESET_TIMER : BLK_EH_NOT_HANDLED;
 625 }
 626
 627 static void srp_rport_release(struct device *dev)
 628 {
 629         struct srp_rport *rport = dev_to_rport(dev);
 630
 631         put_device(dev->parent);
 632         kfree(rport);
 633 }
 634
 635 static int scsi_is_srp_rport(const struct device *dev)
 636 {
 637         return dev->release == srp_rport_release;
 638 }
 639
 640 static int srp_rport_match(struct attribute_container *cont,
 641                            struct device *dev)
 642 {
 643         struct Scsi_Host *shost;
 644         struct srp_internal *i;
 645
 646         if (!scsi_is_srp_rport(dev))
 647                 return 0;
 648
 649         shost = dev_to_shost(dev->parent);
 650         if (!shost->transportt)
 651                 return 0;
 652         if (shost->transportt->host_attrs.ac.class != &srp_host_class.class)
 653                 return 0;
 654
 655         i = to_srp_internal(shost->transportt);
 656         return &i->rport_attr_cont.ac == cont;
 657 }
 658
 659 static int srp_host_match(struct attribute_container *cont, struct device *dev)
 660 {
 661         struct Scsi_Host *shost;
 662         struct srp_internal *i;
 663
 664         if (!scsi_is_host_device(dev))
 665                 return 0;
 666
 667         shost = dev_to_shost(dev);
 668         if (!shost->transportt)
 669                 return 0;
 670         if (shost->transportt->host_attrs.ac.class != &srp_host_class.class)
 671                 return 0;
 672
 673         i = to_srp_internal(shost->transportt);
 674         return &i->t.host_attrs.ac == cont;
 675 }
 676
 677 /**
 678  * srp_rport_get() - increment rport reference count
 679  * @rport: SRP target port.
 680  */
 681 void srp_rport_get(struct srp_rport *rport)
 682 {
 683         get_device(&rport->dev);
 684 }
 685 EXPORT_SYMBOL(srp_rport_get);
 686
 687 /**
 688  * srp_rport_put() - decrement rport reference count
 689  * @rport: SRP target port.
 690  */
 691 void srp_rport_put(struct srp_rport *rport)
 692 {
 693         put_device(&rport->dev);
 694 }
 695 EXPORT_SYMBOL(srp_rport_put);
 696
 697 /**
 698  * srp_rport_add - add a SRP remote port to the device hierarchy
 699  * @shost:      scsi host the remote port is connected to.
 700  * @ids:        The port id for the remote port.
 701  *
 702  * Publishes a port to the rest of the system.
 703  */
 704 struct srp_rport *srp_rport_add(struct Scsi_Host *shost,
 705                                 struct srp_rport_identifiers *ids)
 706 {
 707         struct srp_rport *rport;
 708         struct device *parent = &shost->shost_gendev;
 709         struct srp_internal *i = to_srp_internal(shost->transportt);
 710         int id, ret;
 711
 712         rport = kzalloc(sizeof(*rport), GFP_KERNEL);
 713         if (!rport)
 714                 return ERR_PTR(-ENOMEM);
 715
 716         mutex_init(&rport->mutex);
 717
 718         device_initialize(&rport->dev);
 719
 720         rport->dev.parent = get_device(parent);
 721         rport->dev.release = srp_rport_release;
 722
 723         memcpy(rport->port_id, ids->port_id, sizeof(rport->port_id));
 724         rport->roles = ids->roles;
 725
 726         if (i->f->reconnect)
 727                 rport->reconnect_delay = i->f->reconnect_delay ?
 728                         *i->f->reconnect_delay : 10;
 729         INIT_DELAYED_WORK(&rport->reconnect_work, srp_reconnect_work);
 730         rport->fast_io_fail_tmo = i->f->fast_io_fail_tmo ?
 731                 *i->f->fast_io_fail_tmo : 15;
 732         rport->dev_loss_tmo = i->f->dev_loss_tmo ? *i->f->dev_loss_tmo : 60;
 733         INIT_DELAYED_WORK(&rport->fast_io_fail_work,
 734                           rport_fast_io_fail_timedout);
 735         INIT_DELAYED_WORK(&rport->dev_loss_work, rport_dev_loss_timedout);
 736
 737         id = atomic_inc_return(&to_srp_host_attrs(shost)->next_port_id);
 738         dev_set_name(&rport->dev, "port-%d:%d", shost->host_no, id);
 739
 740         transport_setup_device(&rport->dev);
 741
 742         ret = device_add(&rport->dev);
 743         if (ret) {
 744                 transport_destroy_device(&rport->dev);
 745                 put_device(&rport->dev);
 746                 return ERR_PTR(ret);
 747         }
 748
 749         transport_add_device(&rport->dev);
 750         transport_configure_device(&rport->dev);
 751
 752         return rport;
 753 }
 754 EXPORT_SYMBOL_GPL(srp_rport_add);
 755
 756 /**
 757  * srp_rport_del  -  remove a SRP remote port
 758  * @rport:      SRP remote port to remove
 759  *
 760  * Removes the specified SRP remote port.
 761  */
 762 void srp_rport_del(struct srp_rport *rport)
 763 {
 764         struct device *dev = &rport->dev;
 765
 766         transport_remove_device(dev);
 767         device_del(dev);
 768         transport_destroy_device(dev);
 769
 770         put_device(dev);
 771 }
 772 EXPORT_SYMBOL_GPL(srp_rport_del);
 773
 774 static int do_srp_rport_del(struct device *dev, void *data)
 775 {
 776         if (scsi_is_srp_rport(dev))
 777                 srp_rport_del(dev_to_rport(dev));
 778         return 0;
 779 }
 780
 781 /**
 782  * srp_remove_host  -  tear down a Scsi_Host's SRP data structures
 783  * @shost:      Scsi Host that is torn down
 784  *
 785  * Removes all SRP remote ports for a given Scsi_Host.
 786  * Must be called just before scsi_remove_host for SRP HBAs.
 787  */
 788 void srp_remove_host(struct Scsi_Host *shost)
 789 {
 790         device_for_each_child(&shost->shost_gendev, NULL, do_srp_rport_del);
 791 }
 792 EXPORT_SYMBOL_GPL(srp_remove_host);
 793
 794 /**
 795  * srp_stop_rport_timers - stop the transport layer recovery timers
 796  * @rport: SRP remote port for which to stop the timers.
 797  *
 798  * Must be called after srp_remove_host() and scsi_remove_host(). The caller
 799  * must hold a reference on the rport (rport->dev) and on the SCSI host
 800  * (rport->dev.parent).
 801  */
 802 void srp_stop_rport_timers(struct srp_rport *rport)
 803 {
 804         mutex_lock(&rport->mutex);
 805         if (rport->state == SRP_RPORT_BLOCKED)
 806                 __rport_fail_io_fast(rport);
 807         srp_rport_set_state(rport, SRP_RPORT_LOST);
 808         mutex_unlock(&rport->mutex);
 809
 810         cancel_delayed_work_sync(&rport->reconnect_work);
 811         cancel_delayed_work_sync(&rport->fast_io_fail_work);
 812         cancel_delayed_work_sync(&rport->dev_loss_work);
 813 }
 814 EXPORT_SYMBOL_GPL(srp_stop_rport_timers);
 815
 816 static int srp_tsk_mgmt_response(struct Scsi_Host *shost, u64 nexus, u64 tm_id,
 817                                  int result)
 818 {
 819         struct srp_internal *i = to_srp_internal(shost->transportt);
 820         return i->f->tsk_mgmt_response(shost, nexus, tm_id, result);
 821 }
 822
 823 static int srp_it_nexus_response(struct Scsi_Host *shost, u64 nexus, int result)
 824 {
 825         struct srp_internal *i = to_srp_internal(shost->transportt);
 826         return i->f->it_nexus_response(shost, nexus, result);
 827 }
 828
 829 /**
 830  * srp_attach_transport  -  instantiate SRP transport template
 831  * @ft:         SRP transport class function template
 832  */
 833 struct scsi_transport_template *
 834 srp_attach_transport(struct srp_function_template *ft)
 835 {
 836         int count;
 837         struct srp_internal *i;
 838
 839         i = kzalloc(sizeof(*i), GFP_KERNEL);
 840         if (!i)
 841                 return NULL;
 842
 843         i->t.eh_timed_out = srp_timed_out;
 844
 845         i->t.tsk_mgmt_response = srp_tsk_mgmt_response;
 846         i->t.it_nexus_response = srp_it_nexus_response;
 847
 848         i->t.host_size = sizeof(struct srp_host_attrs);
 849         i->t.host_attrs.ac.attrs = &i->host_attrs[0];
 850         i->t.host_attrs.ac.class = &srp_host_class.class;
 851         i->t.host_attrs.ac.match = srp_host_match;
 852         i->host_attrs[0] = NULL;
 853         transport_container_register(&i->t.host_attrs);
 854
 855         i->rport_attr_cont.ac.attrs = &i->rport_attrs[0];
 856         i->rport_attr_cont.ac.class = &srp_rport_class.class;
 857         i->rport_attr_cont.ac.match = srp_rport_match;
 858
 859         count = 0;
 860         i->rport_attrs[count++] = &dev_attr_port_id;
 861         i->rport_attrs[count++] = &dev_attr_roles;
 862         if (ft->has_rport_state) {
 863                 i->rport_attrs[count++] = &dev_attr_state;
 864                 i->rport_attrs[count++] = &dev_attr_fast_io_fail_tmo;
 865                 i->rport_attrs[count++] = &dev_attr_dev_loss_tmo;
 866         }
 867         if (ft->reconnect) {
 868                 i->rport_attrs[count++] = &dev_attr_reconnect_delay;
 869                 i->rport_attrs[count++] = &dev_attr_failed_reconnects;
 870         }
 871         if (ft->rport_delete)
 872                 i->rport_attrs[count++] = &dev_attr_delete;
 873         i->rport_attrs[count++] = NULL;
 874         BUG_ON(count > ARRAY_SIZE(i->rport_attrs));
 875
 876         transport_container_register(&i->rport_attr_cont);
 877
 878         i->f = ft;
 879
 880         return &i->t;
 881 }
 882 EXPORT_SYMBOL_GPL(srp_attach_transport);
 883
 884 /**
 885  * srp_release_transport  -  release SRP transport template instance
 886  * @t:          transport template instance
 887  */
 888 void srp_release_transport(struct scsi_transport_template *t)
 889 {
 890         struct srp_internal *i = to_srp_internal(t);
 891
 892         transport_container_unregister(&i->t.host_attrs);
 893         transport_container_unregister(&i->rport_attr_cont);
 894
 895         kfree(i);
 896 }
 897 EXPORT_SYMBOL_GPL(srp_release_transport);
 898
 899 static __init int srp_transport_init(void)
 900 {
 901         int ret;
 902
 903         ret = transport_class_register(&srp_host_class);
 904         if (ret)
 905                 return ret;
 906         ret = transport_class_register(&srp_rport_class);
 907         if (ret)
 908                 goto unregister_host_class;
 909
 910         return 0;
 911 unregister_host_class:
 912         transport_class_unregister(&srp_host_class);
 913         return ret;
 914 }
 915
 916 static void __exit srp_transport_exit(void)
 917 {
 918         transport_class_unregister(&srp_host_class);
 919         transport_class_unregister(&srp_rport_class);
 920 }
 921
 922 MODULE_AUTHOR("FUJITA Tomonori");
 923 MODULE_DESCRIPTION("SRP Transport Attributes");
 924 MODULE_LICENSE("GPL");
 925
 926 module_init(srp_transport_init);
 927 module_exit(srp_transport_exit);