drivers/scsi/scsi_transport_srp.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * SCSI RDMA (SRP) transport class
   4  *
   5  * Copyright (C) 2007 FUJITA Tomonori <tomof@acm.org>
   6  */
   7 #include <linux/init.h>
   8 #include <linux/module.h>
   9 #include <linux/jiffies.h>
  10 #include <linux/err.h>
  11 #include <linux/slab.h>
  12 #include <linux/string.h>
  13
  14 #include <scsi/scsi.h>
  15 #include <scsi/scsi_cmnd.h>
  16 #include <scsi/scsi_device.h>
  17 #include <scsi/scsi_host.h>
  18 #include <scsi/scsi_transport.h>
  19 #include <scsi/scsi_transport_srp.h>
  20 #include "scsi_priv.h"
  21
  22 struct srp_host_attrs {
  23         atomic_t next_port_id;
  24 };
  25 #define to_srp_host_attrs(host) ((struct srp_host_attrs *)(host)->shost_data)
  26
  27 #define SRP_HOST_ATTRS 0
  28 #define SRP_RPORT_ATTRS 8
  29
  30 struct srp_internal {
  31         struct scsi_transport_template t;
  32         struct srp_function_template *f;
  33
  34         struct device_attribute *host_attrs[SRP_HOST_ATTRS + 1];
  35
  36         struct device_attribute *rport_attrs[SRP_RPORT_ATTRS + 1];
  37         struct transport_container rport_attr_cont;
  38 };
  39
  40 static int scsi_is_srp_rport(const struct device *dev);
  41
  42 #define to_srp_internal(tmpl) container_of(tmpl, struct srp_internal, t)
  43
  44 #define dev_to_rport(d) container_of(d, struct srp_rport, dev)
  45 #define transport_class_to_srp_rport(dev) dev_to_rport((dev)->parent)
  46 static inline struct Scsi_Host *rport_to_shost(struct srp_rport *r)
  47 {
  48         return dev_to_shost(r->dev.parent);
  49 }
  50
  51 static int find_child_rport(struct device *dev, void *data)
  52 {
  53         struct device **child = data;
  54
  55         if (scsi_is_srp_rport(dev)) {
  56                 WARN_ON_ONCE(*child);
  57                 *child = dev;
  58         }
  59         return 0;
  60 }
  61
  62 static inline struct srp_rport *shost_to_rport(struct Scsi_Host *shost)
  63 {
  64         struct device *child = NULL;
  65
  66         WARN_ON_ONCE(device_for_each_child(&shost->shost_gendev, &child,
  67                                            find_child_rport) < 0);
  68         return child ? dev_to_rport(child) : NULL;
  69 }
  70
  71 /**
  72  * srp_tmo_valid() - check timeout combination validity
  73  * @reconnect_delay: Reconnect delay in seconds.
  74  * @fast_io_fail_tmo: Fast I/O fail timeout in seconds.
  75  * @dev_loss_tmo: Device loss timeout in seconds.
  76  *
  77  * The combination of the timeout parameters must be such that SCSI commands
  78  * are finished in a reasonable time. Hence do not allow the fast I/O fail
  79  * timeout to exceed SCSI_DEVICE_BLOCK_MAX_TIMEOUT nor allow dev_loss_tmo to
  80  * exceed that limit if failing I/O fast has been disabled. Furthermore, these
  81  * parameters must be such that multipath can detect failed paths timely.
  82  * Hence do not allow all three parameters to be disabled simultaneously.
  83  */
  84 int srp_tmo_valid(int reconnect_delay, int fast_io_fail_tmo, long dev_loss_tmo)
  85 {
  86         if (reconnect_delay < 0 && fast_io_fail_tmo < 0 && dev_loss_tmo < 0)
  87                 return -EINVAL;
  88         if (reconnect_delay == 0)
  89                 return -EINVAL;
  90         if (fast_io_fail_tmo > SCSI_DEVICE_BLOCK_MAX_TIMEOUT)
  91                 return -EINVAL;
  92         if (fast_io_fail_tmo < 0 &&
  93             dev_loss_tmo > SCSI_DEVICE_BLOCK_MAX_TIMEOUT)
  94                 return -EINVAL;
  95         if (dev_loss_tmo >= LONG_MAX / HZ)
  96                 return -EINVAL;
  97         if (fast_io_fail_tmo >= 0 && dev_loss_tmo >= 0 &&
  98             fast_io_fail_tmo >= dev_loss_tmo)
  99                 return -EINVAL;
 100         return 0;
 101 }
 102 EXPORT_SYMBOL_GPL(srp_tmo_valid);
 103
 104 static int srp_host_setup(struct transport_container *tc, struct device *dev,
 105                           struct device *cdev)
 106 {
 107         struct Scsi_Host *shost = dev_to_shost(dev);
 108         struct srp_host_attrs *srp_host = to_srp_host_attrs(shost);
 109
 110         atomic_set(&srp_host->next_port_id, 0);
 111         return 0;
 112 }
 113
 114 static DECLARE_TRANSPORT_CLASS(srp_host_class, "srp_host", srp_host_setup,
 115                                NULL, NULL);
 116
 117 static DECLARE_TRANSPORT_CLASS(srp_rport_class, "srp_remote_ports",
 118                                NULL, NULL, NULL);
 119
 120 static ssize_t
 121 show_srp_rport_id(struct device *dev, struct device_attribute *attr,
 122                   char *buf)
 123 {
 124         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 125         return sprintf(buf, "%16phC\n", rport->port_id);
 126 }
 127
 128 static DEVICE_ATTR(port_id, S_IRUGO, show_srp_rport_id, NULL);
 129
 130 static const struct {
 131         u32 value;
 132         char *name;
 133 } srp_rport_role_names[] = {
 134         {SRP_RPORT_ROLE_INITIATOR, "SRP Initiator"},
 135         {SRP_RPORT_ROLE_TARGET, "SRP Target"},
 136 };
 137
 138 static ssize_t
 139 show_srp_rport_roles(struct device *dev, struct device_attribute *attr,
 140                      char *buf)
 141 {
 142         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 143         int i;
 144         char *name = NULL;
 145
 146         for (i = 0; i < ARRAY_SIZE(srp_rport_role_names); i++)
 147                 if (srp_rport_role_names[i].value == rport->roles) {
 148                         name = srp_rport_role_names[i].name;
 149                         break;
 150                 }
 151         return sprintf(buf, "%s\n", name ? : "unknown");
 152 }
 153
 154 static DEVICE_ATTR(roles, S_IRUGO, show_srp_rport_roles, NULL);
 155
 156 static ssize_t store_srp_rport_delete(struct device *dev,
 157                                       struct device_attribute *attr,
 158                                       const char *buf, size_t count)
 159 {
 160         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 161         struct Scsi_Host *shost = dev_to_shost(dev);
 162         struct srp_internal *i = to_srp_internal(shost->transportt);
 163
 164         if (i->f->rport_delete) {
 165                 i->f->rport_delete(rport);
 166                 return count;
 167         } else {
 168                 return -ENOSYS;
 169         }
 170 }
 171
 172 static DEVICE_ATTR(delete, S_IWUSR, NULL, store_srp_rport_delete);
 173
 174 static ssize_t show_srp_rport_state(struct device *dev,
 175                                     struct device_attribute *attr,
 176                                     char *buf)
 177 {
 178         static const char *const state_name[] = {
 179                 [SRP_RPORT_RUNNING]     = "running",
 180                 [SRP_RPORT_BLOCKED]     = "blocked",
 181                 [SRP_RPORT_FAIL_FAST]   = "fail-fast",
 182                 [SRP_RPORT_LOST]        = "lost",
 183         };
 184         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 185         enum srp_rport_state state = rport->state;
 186
 187         return sprintf(buf, "%s\n",
 188                        (unsigned)state < ARRAY_SIZE(state_name) ?
 189                        state_name[state] : "???");
 190 }
 191
 192 static DEVICE_ATTR(state, S_IRUGO, show_srp_rport_state, NULL);
 193
 194 static ssize_t srp_show_tmo(char *buf, int tmo)
 195 {
 196         return tmo >= 0 ? sprintf(buf, "%d\n", tmo) : sprintf(buf, "off\n");
 197 }
 198
 199 int srp_parse_tmo(int *tmo, const char *buf)
 200 {
 201         int res = 0;
 202
 203         if (strncmp(buf, "off", 3) != 0)
 204                 res = kstrtoint(buf, 0, tmo);
 205         else
 206                 *tmo = -1;
 207
 208         return res;
 209 }
 210 EXPORT_SYMBOL(srp_parse_tmo);
 211
 212 static ssize_t show_reconnect_delay(struct device *dev,
 213                                     struct device_attribute *attr, char *buf)
 214 {
 215         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 216
 217         return srp_show_tmo(buf, rport->reconnect_delay);
 218 }
 219
 220 static ssize_t store_reconnect_delay(struct device *dev,
 221                                      struct device_attribute *attr,
 222                                      const char *buf, const size_t count)
 223 {
 224         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 225         int res, delay;
 226
 227         res = srp_parse_tmo(&delay, buf);
 228         if (res)
 229                 goto out;
 230         res = srp_tmo_valid(delay, rport->fast_io_fail_tmo,
 231                             rport->dev_loss_tmo);
 232         if (res)
 233                 goto out;
 234
 235         if (rport->reconnect_delay <= 0 && delay > 0 &&
 236             rport->state != SRP_RPORT_RUNNING) {
 237                 queue_delayed_work(system_long_wq, &rport->reconnect_work,
 238                                    delay * HZ);
 239         } else if (delay <= 0) {
 240                 cancel_delayed_work(&rport->reconnect_work);
 241         }
 242         rport->reconnect_delay = delay;
 243         res = count;
 244
 245 out:
 246         return res;
 247 }
 248
 249 static DEVICE_ATTR(reconnect_delay, S_IRUGO | S_IWUSR, show_reconnect_delay,
 250                    store_reconnect_delay);
 251
 252 static ssize_t show_failed_reconnects(struct device *dev,
 253                                       struct device_attribute *attr, char *buf)
 254 {
 255         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 256
 257         return sprintf(buf, "%d\n", rport->failed_reconnects);
 258 }
 259
 260 static DEVICE_ATTR(failed_reconnects, S_IRUGO, show_failed_reconnects, NULL);
 261
 262 static ssize_t show_srp_rport_fast_io_fail_tmo(struct device *dev,
 263                                                struct device_attribute *attr,
 264                                                char *buf)
 265 {
 266         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 267
 268         return srp_show_tmo(buf, rport->fast_io_fail_tmo);
 269 }
 270
 271 static ssize_t store_srp_rport_fast_io_fail_tmo(struct device *dev,
 272                                                 struct device_attribute *attr,
 273                                                 const char *buf, size_t count)
 274 {
 275         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 276         int res;
 277         int fast_io_fail_tmo;
 278
 279         res = srp_parse_tmo(&fast_io_fail_tmo, buf);
 280         if (res)
 281                 goto out;
 282         res = srp_tmo_valid(rport->reconnect_delay, fast_io_fail_tmo,
 283                             rport->dev_loss_tmo);
 284         if (res)
 285                 goto out;
 286         rport->fast_io_fail_tmo = fast_io_fail_tmo;
 287         res = count;
 288
 289 out:
 290         return res;
 291 }
 292
 293 static DEVICE_ATTR(fast_io_fail_tmo, S_IRUGO | S_IWUSR,
 294                    show_srp_rport_fast_io_fail_tmo,
 295                    store_srp_rport_fast_io_fail_tmo);
 296
 297 static ssize_t show_srp_rport_dev_loss_tmo(struct device *dev,
 298                                            struct device_attribute *attr,
 299                                            char *buf)
 300 {
 301         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 302
 303         return srp_show_tmo(buf, rport->dev_loss_tmo);
 304 }
 305
 306 static ssize_t store_srp_rport_dev_loss_tmo(struct device *dev,
 307                                             struct device_attribute *attr,
 308                                             const char *buf, size_t count)
 309 {
 310         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 311         int res;
 312         int dev_loss_tmo;
 313
 314         res = srp_parse_tmo(&dev_loss_tmo, buf);
 315         if (res)
 316                 goto out;
 317         res = srp_tmo_valid(rport->reconnect_delay, rport->fast_io_fail_tmo,
 318                             dev_loss_tmo);
 319         if (res)
 320                 goto out;
 321         rport->dev_loss_tmo = dev_loss_tmo;
 322         res = count;
 323
 324 out:
 325         return res;
 326 }
 327
 328 static DEVICE_ATTR(dev_loss_tmo, S_IRUGO | S_IWUSR,
 329                    show_srp_rport_dev_loss_tmo,
 330                    store_srp_rport_dev_loss_tmo);
 331
 332 static int srp_rport_set_state(struct srp_rport *rport,
 333                                enum srp_rport_state new_state)
 334 {
 335         enum srp_rport_state old_state = rport->state;
 336
 337         lockdep_assert_held(&rport->mutex);
 338
 339         switch (new_state) {
 340         case SRP_RPORT_RUNNING:
 341                 switch (old_state) {
 342                 case SRP_RPORT_LOST:
 343                         goto invalid;
 344                 default:
 345                         break;
 346                 }
 347                 break;
 348         case SRP_RPORT_BLOCKED:
 349                 switch (old_state) {
 350                 case SRP_RPORT_RUNNING:
 351                         break;
 352                 default:
 353                         goto invalid;
 354                 }
 355                 break;
 356         case SRP_RPORT_FAIL_FAST:
 357                 switch (old_state) {
 358                 case SRP_RPORT_LOST:
 359                         goto invalid;
 360                 default:
 361                         break;
 362                 }
 363                 break;
 364         case SRP_RPORT_LOST:
 365                 break;
 366         }
 367         rport->state = new_state;
 368         return 0;
 369
 370 invalid:
 371         return -EINVAL;
 372 }
 373
 374 /**
 375  * srp_reconnect_work() - reconnect and schedule a new attempt if necessary
 376  * @work: Work structure used for scheduling this operation.
 377  */
 378 static void srp_reconnect_work(struct work_struct *work)
 379 {
 380         struct srp_rport *rport = container_of(to_delayed_work(work),
 381                                         struct srp_rport, reconnect_work);
 382         struct Scsi_Host *shost = rport_to_shost(rport);
 383         int delay, res;
 384
 385         res = srp_reconnect_rport(rport);
 386         if (res != 0) {
 387                 shost_printk(KERN_ERR, shost,
 388                              "reconnect attempt %d failed (%d)\n",
 389                              ++rport->failed_reconnects, res);
 390                 delay = rport->reconnect_delay *
 391                         min(100, max(1, rport->failed_reconnects - 10));
 392                 if (delay > 0)
 393                         queue_delayed_work(system_long_wq,
 394                                            &rport->reconnect_work, delay * HZ);
 395         }
 396 }
 397
 398 /*
 399  * scsi_target_block() must have been called before this function is
 400  * called to guarantee that no .queuecommand() calls are in progress.
 401  */
 402 static void __rport_fail_io_fast(struct srp_rport *rport)
 403 {
 404         struct Scsi_Host *shost = rport_to_shost(rport);
 405         struct srp_internal *i;
 406
 407         lockdep_assert_held(&rport->mutex);
 408
 409         if (srp_rport_set_state(rport, SRP_RPORT_FAIL_FAST))
 410                 return;
 411
 412         scsi_target_unblock(rport->dev.parent, SDEV_TRANSPORT_OFFLINE);
 413
 414         /* Involve the LLD if possible to terminate all I/O on the rport. */
 415         i = to_srp_internal(shost->transportt);
 416         if (i->f->terminate_rport_io)
 417                 i->f->terminate_rport_io(rport);
 418 }
 419
 420 /**
 421  * rport_fast_io_fail_timedout() - fast I/O failure timeout handler
 422  * @work: Work structure used for scheduling this operation.
 423  */
 424 static void rport_fast_io_fail_timedout(struct work_struct *work)
 425 {
 426         struct srp_rport *rport = container_of(to_delayed_work(work),
 427                                         struct srp_rport, fast_io_fail_work);
 428         struct Scsi_Host *shost = rport_to_shost(rport);
 429
 430         pr_info("fast_io_fail_tmo expired for SRP %s / %s.\n",
 431                 dev_name(&rport->dev), dev_name(&shost->shost_gendev));
 432
 433         mutex_lock(&rport->mutex);
 434         if (rport->state == SRP_RPORT_BLOCKED)
 435                 __rport_fail_io_fast(rport);
 436         mutex_unlock(&rport->mutex);
 437 }
 438
 439 /**
 440  * rport_dev_loss_timedout() - device loss timeout handler
 441  * @work: Work structure used for scheduling this operation.
 442  */
 443 static void rport_dev_loss_timedout(struct work_struct *work)
 444 {
 445         struct srp_rport *rport = container_of(to_delayed_work(work),
 446                                         struct srp_rport, dev_loss_work);
 447         struct Scsi_Host *shost = rport_to_shost(rport);
 448         struct srp_internal *i = to_srp_internal(shost->transportt);
 449
 450         pr_info("dev_loss_tmo expired for SRP %s / %s.\n",
 451                 dev_name(&rport->dev), dev_name(&shost->shost_gendev));
 452
 453         mutex_lock(&rport->mutex);
 454         WARN_ON(srp_rport_set_state(rport, SRP_RPORT_LOST) != 0);
 455         scsi_target_unblock(rport->dev.parent, SDEV_TRANSPORT_OFFLINE);
 456         mutex_unlock(&rport->mutex);
 457
 458         i->f->rport_delete(rport);
 459 }
 460
 461 static void __srp_start_tl_fail_timers(struct srp_rport *rport)
 462 {
 463         struct Scsi_Host *shost = rport_to_shost(rport);
 464         int delay, fast_io_fail_tmo, dev_loss_tmo;
 465
 466         lockdep_assert_held(&rport->mutex);
 467
 468         delay = rport->reconnect_delay;
 469         fast_io_fail_tmo = rport->fast_io_fail_tmo;
 470         dev_loss_tmo = rport->dev_loss_tmo;
 471         pr_debug("%s current state: %d\n", dev_name(&shost->shost_gendev),
 472                  rport->state);
 473
 474         if (rport->state == SRP_RPORT_LOST)
 475                 return;
 476         if (delay > 0)
 477                 queue_delayed_work(system_long_wq, &rport->reconnect_work,
 478                                    1UL * delay * HZ);
 479         if ((fast_io_fail_tmo >= 0 || dev_loss_tmo >= 0) &&
 480             srp_rport_set_state(rport, SRP_RPORT_BLOCKED) == 0) {
 481                 pr_debug("%s new state: %d\n", dev_name(&shost->shost_gendev),
 482                          rport->state);
 483                 scsi_target_block(&shost->shost_gendev);
 484                 if (fast_io_fail_tmo >= 0)
 485                         queue_delayed_work(system_long_wq,
 486                                            &rport->fast_io_fail_work,
 487                                            1UL * fast_io_fail_tmo * HZ);
 488                 if (dev_loss_tmo >= 0)
 489                         queue_delayed_work(system_long_wq,
 490                                            &rport->dev_loss_work,
 491                                            1UL * dev_loss_tmo * HZ);
 492         }
 493 }
 494
 495 /**
 496  * srp_start_tl_fail_timers() - start the transport layer failure timers
 497  * @rport: SRP target port.
 498  *
 499  * Start the transport layer fast I/O failure and device loss timers. Do not
 500  * modify a timer that was already started.
 501  */
 502 void srp_start_tl_fail_timers(struct srp_rport *rport)
 503 {
 504         mutex_lock(&rport->mutex);
 505         __srp_start_tl_fail_timers(rport);
 506         mutex_unlock(&rport->mutex);
 507 }
 508 EXPORT_SYMBOL(srp_start_tl_fail_timers);
 509
 510 /**
 511  * srp_reconnect_rport() - reconnect to an SRP target port
 512  * @rport: SRP target port.
 513  *
 514  * Blocks SCSI command queueing before invoking reconnect() such that
 515  * queuecommand() won't be invoked concurrently with reconnect() from outside
 516  * the SCSI EH. This is important since a reconnect() implementation may
 517  * reallocate resources needed by queuecommand().
 518  *
 519  * Notes:
 520  * - This function neither waits until outstanding requests have finished nor
 521  *   tries to abort these. It is the responsibility of the reconnect()
 522  *   function to finish outstanding commands before reconnecting to the target
 523  *   port.
 524  * - It is the responsibility of the caller to ensure that the resources
 525  *   reallocated by the reconnect() function won't be used while this function
 526  *   is in progress. One possible strategy is to invoke this function from
 527  *   the context of the SCSI EH thread only. Another possible strategy is to
 528  *   lock the rport mutex inside each SCSI LLD callback that can be invoked by
 529  *   the SCSI EH (the scsi_host_template.eh_*() functions and also the
 530  *   scsi_host_template.queuecommand() function).
 531  */
 532 int srp_reconnect_rport(struct srp_rport *rport)
 533 {
 534         struct Scsi_Host *shost = rport_to_shost(rport);
 535         struct srp_internal *i = to_srp_internal(shost->transportt);
 536         struct scsi_device *sdev;
 537         int res;
 538
 539         pr_debug("SCSI host %s\n", dev_name(&shost->shost_gendev));
 540
 541         res = mutex_lock_interruptible(&rport->mutex);
 542         if (res)
 543                 goto out;
 544         if (rport->state != SRP_RPORT_FAIL_FAST && rport->state != SRP_RPORT_LOST)
 545                 /*
 546                  * sdev state must be SDEV_TRANSPORT_OFFLINE, transition
 547                  * to SDEV_BLOCK is illegal. Calling scsi_target_unblock()
 548                  * later is ok though, scsi_internal_device_unblock_nowait()
 549                  * treats SDEV_TRANSPORT_OFFLINE like SDEV_BLOCK.
 550                  */
 551                 scsi_target_block(&shost->shost_gendev);
 552         res = rport->state != SRP_RPORT_LOST ? i->f->reconnect(rport) : -ENODEV;
 553         pr_debug("%s (state %d): transport.reconnect() returned %d\n",
 554                  dev_name(&shost->shost_gendev), rport->state, res);
 555         if (res == 0) {
 556                 cancel_delayed_work(&rport->fast_io_fail_work);
 557                 cancel_delayed_work(&rport->dev_loss_work);
 558
 559                 rport->failed_reconnects = 0;
 560                 srp_rport_set_state(rport, SRP_RPORT_RUNNING);
 561                 scsi_target_unblock(&shost->shost_gendev, SDEV_RUNNING);
 562                 /*
 563                  * If the SCSI error handler has offlined one or more devices,
 564                  * invoking scsi_target_unblock() won't change the state of
 565                  * these devices into running so do that explicitly.
 566                  */
 567                 shost_for_each_device(sdev, shost) {
 568                         mutex_lock(&sdev->state_mutex);
 569                         if (sdev->sdev_state == SDEV_OFFLINE)
 570                                 sdev->sdev_state = SDEV_RUNNING;
 571                         mutex_unlock(&sdev->state_mutex);
 572                 }
 573         } else if (rport->state == SRP_RPORT_RUNNING) {
 574                 /*
 575                  * srp_reconnect_rport() has been invoked with fast_io_fail
 576                  * and dev_loss off. Mark the port as failed and start the TL
 577                  * failure timers if these had not yet been started.
 578                  */
 579                 __rport_fail_io_fast(rport);
 580                 __srp_start_tl_fail_timers(rport);
 581         } else if (rport->state != SRP_RPORT_BLOCKED) {
 582                 scsi_target_unblock(&shost->shost_gendev,
 583                                     SDEV_TRANSPORT_OFFLINE);
 584         }
 585         mutex_unlock(&rport->mutex);
 586
 587 out:
 588         return res;
 589 }
 590 EXPORT_SYMBOL(srp_reconnect_rport);
 591
 592 /**
 593  * srp_timed_out() - SRP transport intercept of the SCSI timeout EH
 594  * @scmd: SCSI command.
 595  *
 596  * If a timeout occurs while an rport is in the blocked state, ask the SCSI
 597  * EH to continue waiting (BLK_EH_RESET_TIMER). Otherwise let the SCSI core
 598  * handle the timeout (BLK_EH_DONE).
 599  *
 600  * Note: This function is called from soft-IRQ context and with the request
 601  * queue lock held.
 602  */
 603 enum blk_eh_timer_return srp_timed_out(struct scsi_cmnd *scmd)
 604 {
 605         struct scsi_device *sdev = scmd->device;
 606         struct Scsi_Host *shost = sdev->host;
 607         struct srp_internal *i = to_srp_internal(shost->transportt);
 608         struct srp_rport *rport = shost_to_rport(shost);
 609
 610         pr_debug("timeout for sdev %s\n", dev_name(&sdev->sdev_gendev));
 611         return rport && rport->fast_io_fail_tmo < 0 &&
 612                 rport->dev_loss_tmo < 0 &&
 613                 i->f->reset_timer_if_blocked && scsi_device_blocked(sdev) ?
 614                 BLK_EH_RESET_TIMER : BLK_EH_DONE;
 615 }
 616 EXPORT_SYMBOL(srp_timed_out);
 617
 618 static void srp_rport_release(struct device *dev)
 619 {
 620         struct srp_rport *rport = dev_to_rport(dev);
 621
 622         put_device(dev->parent);
 623         kfree(rport);
 624 }
 625
 626 static int scsi_is_srp_rport(const struct device *dev)
 627 {
 628         return dev->release == srp_rport_release;
 629 }
 630
 631 static int srp_rport_match(struct attribute_container *cont,
 632                            struct device *dev)
 633 {
 634         struct Scsi_Host *shost;
 635         struct srp_internal *i;
 636
 637         if (!scsi_is_srp_rport(dev))
 638                 return 0;
 639
 640         shost = dev_to_shost(dev->parent);
 641         if (!shost->transportt)
 642                 return 0;
 643         if (shost->transportt->host_attrs.ac.class != &srp_host_class.class)
 644                 return 0;
 645
 646         i = to_srp_internal(shost->transportt);
 647         return &i->rport_attr_cont.ac == cont;
 648 }
 649
 650 static int srp_host_match(struct attribute_container *cont, struct device *dev)
 651 {
 652         struct Scsi_Host *shost;
 653         struct srp_internal *i;
 654
 655         if (!scsi_is_host_device(dev))
 656                 return 0;
 657
 658         shost = dev_to_shost(dev);
 659         if (!shost->transportt)
 660                 return 0;
 661         if (shost->transportt->host_attrs.ac.class != &srp_host_class.class)
 662                 return 0;
 663
 664         i = to_srp_internal(shost->transportt);
 665         return &i->t.host_attrs.ac == cont;
 666 }
 667
 668 /**
 669  * srp_rport_get() - increment rport reference count
 670  * @rport: SRP target port.
 671  */
 672 void srp_rport_get(struct srp_rport *rport)
 673 {
 674         get_device(&rport->dev);
 675 }
 676 EXPORT_SYMBOL(srp_rport_get);
 677
 678 /**
 679  * srp_rport_put() - decrement rport reference count
 680  * @rport: SRP target port.
 681  */
 682 void srp_rport_put(struct srp_rport *rport)
 683 {
 684         put_device(&rport->dev);
 685 }
 686 EXPORT_SYMBOL(srp_rport_put);
 687
 688 /**
 689  * srp_rport_add - add a SRP remote port to the device hierarchy
 690  * @shost:      scsi host the remote port is connected to.
 691  * @ids:        The port id for the remote port.
 692  *
 693  * Publishes a port to the rest of the system.
 694  */
 695 struct srp_rport *srp_rport_add(struct Scsi_Host *shost,
 696                                 struct srp_rport_identifiers *ids)
 697 {
 698         struct srp_rport *rport;
 699         struct device *parent = &shost->shost_gendev;
 700         struct srp_internal *i = to_srp_internal(shost->transportt);
 701         int id, ret;
 702
 703         rport = kzalloc(sizeof(*rport), GFP_KERNEL);
 704         if (!rport)
 705                 return ERR_PTR(-ENOMEM);
 706
 707         mutex_init(&rport->mutex);
 708
 709         device_initialize(&rport->dev);
 710
 711         rport->dev.parent = get_device(parent);
 712         rport->dev.release = srp_rport_release;
 713
 714         memcpy(rport->port_id, ids->port_id, sizeof(rport->port_id));
 715         rport->roles = ids->roles;
 716
 717         if (i->f->reconnect)
 718                 rport->reconnect_delay = i->f->reconnect_delay ?
 719                         *i->f->reconnect_delay : 10;
 720         INIT_DELAYED_WORK(&rport->reconnect_work, srp_reconnect_work);
 721         rport->fast_io_fail_tmo = i->f->fast_io_fail_tmo ?
 722                 *i->f->fast_io_fail_tmo : 15;
 723         rport->dev_loss_tmo = i->f->dev_loss_tmo ? *i->f->dev_loss_tmo : 60;
 724         INIT_DELAYED_WORK(&rport->fast_io_fail_work,
 725                           rport_fast_io_fail_timedout);
 726         INIT_DELAYED_WORK(&rport->dev_loss_work, rport_dev_loss_timedout);
 727
 728         id = atomic_inc_return(&to_srp_host_attrs(shost)->next_port_id);
 729         dev_set_name(&rport->dev, "port-%d:%d", shost->host_no, id);
 730
 731         transport_setup_device(&rport->dev);
 732
 733         ret = device_add(&rport->dev);
 734         if (ret) {
 735                 transport_destroy_device(&rport->dev);
 736                 put_device(&rport->dev);
 737                 return ERR_PTR(ret);
 738         }
 739
 740         transport_add_device(&rport->dev);
 741         transport_configure_device(&rport->dev);
 742
 743         return rport;
 744 }
 745 EXPORT_SYMBOL_GPL(srp_rport_add);
 746
 747 /**
 748  * srp_rport_del  -  remove a SRP remote port
 749  * @rport:      SRP remote port to remove
 750  *
 751  * Removes the specified SRP remote port.
 752  */
 753 void srp_rport_del(struct srp_rport *rport)
 754 {
 755         struct device *dev = &rport->dev;
 756
 757         transport_remove_device(dev);
 758         device_del(dev);
 759         transport_destroy_device(dev);
 760
 761         put_device(dev);
 762 }
 763 EXPORT_SYMBOL_GPL(srp_rport_del);
 764
 765 static int do_srp_rport_del(struct device *dev, void *data)
 766 {
 767         if (scsi_is_srp_rport(dev))
 768                 srp_rport_del(dev_to_rport(dev));
 769         return 0;
 770 }
 771
 772 /**
 773  * srp_remove_host  -  tear down a Scsi_Host's SRP data structures
 774  * @shost:      Scsi Host that is torn down
 775  *
 776  * Removes all SRP remote ports for a given Scsi_Host.
 777  * Must be called just before scsi_remove_host for SRP HBAs.
 778  */
 779 void srp_remove_host(struct Scsi_Host *shost)
 780 {
 781         device_for_each_child(&shost->shost_gendev, NULL, do_srp_rport_del);
 782 }
 783 EXPORT_SYMBOL_GPL(srp_remove_host);
 784
 785 /**
 786  * srp_stop_rport_timers - stop the transport layer recovery timers
 787  * @rport: SRP remote port for which to stop the timers.
 788  *
 789  * Must be called after srp_remove_host() and scsi_remove_host(). The caller
 790  * must hold a reference on the rport (rport->dev) and on the SCSI host
 791  * (rport->dev.parent).
 792  */
 793 void srp_stop_rport_timers(struct srp_rport *rport)
 794 {
 795         mutex_lock(&rport->mutex);
 796         if (rport->state == SRP_RPORT_BLOCKED)
 797                 __rport_fail_io_fast(rport);
 798         srp_rport_set_state(rport, SRP_RPORT_LOST);
 799         mutex_unlock(&rport->mutex);
 800
 801         cancel_delayed_work_sync(&rport->reconnect_work);
 802         cancel_delayed_work_sync(&rport->fast_io_fail_work);
 803         cancel_delayed_work_sync(&rport->dev_loss_work);
 804 }
 805 EXPORT_SYMBOL_GPL(srp_stop_rport_timers);
 806
 807 /**
 808  * srp_attach_transport  -  instantiate SRP transport template
 809  * @ft:         SRP transport class function template
 810  */
 811 struct scsi_transport_template *
 812 srp_attach_transport(struct srp_function_template *ft)
 813 {
 814         int count;
 815         struct srp_internal *i;
 816
 817         i = kzalloc(sizeof(*i), GFP_KERNEL);
 818         if (!i)
 819                 return NULL;
 820
 821         i->t.host_size = sizeof(struct srp_host_attrs);
 822         i->t.host_attrs.ac.attrs = &i->host_attrs[0];
 823         i->t.host_attrs.ac.class = &srp_host_class.class;
 824         i->t.host_attrs.ac.match = srp_host_match;
 825         i->host_attrs[0] = NULL;
 826         transport_container_register(&i->t.host_attrs);
 827
 828         i->rport_attr_cont.ac.attrs = &i->rport_attrs[0];
 829         i->rport_attr_cont.ac.class = &srp_rport_class.class;
 830         i->rport_attr_cont.ac.match = srp_rport_match;
 831
 832         count = 0;
 833         i->rport_attrs[count++] = &dev_attr_port_id;
 834         i->rport_attrs[count++] = &dev_attr_roles;
 835         if (ft->has_rport_state) {
 836                 i->rport_attrs[count++] = &dev_attr_state;
 837                 i->rport_attrs[count++] = &dev_attr_fast_io_fail_tmo;
 838                 i->rport_attrs[count++] = &dev_attr_dev_loss_tmo;
 839         }
 840         if (ft->reconnect) {
 841                 i->rport_attrs[count++] = &dev_attr_reconnect_delay;
 842                 i->rport_attrs[count++] = &dev_attr_failed_reconnects;
 843         }
 844         if (ft->rport_delete)
 845                 i->rport_attrs[count++] = &dev_attr_delete;
 846         i->rport_attrs[count++] = NULL;
 847         BUG_ON(count > ARRAY_SIZE(i->rport_attrs));
 848
 849         transport_container_register(&i->rport_attr_cont);
 850
 851         i->f = ft;
 852
 853         return &i->t;
 854 }
 855 EXPORT_SYMBOL_GPL(srp_attach_transport);
 856
 857 /**
 858  * srp_release_transport  -  release SRP transport template instance
 859  * @t:          transport template instance
 860  */
 861 void srp_release_transport(struct scsi_transport_template *t)
 862 {
 863         struct srp_internal *i = to_srp_internal(t);
 864
 865         transport_container_unregister(&i->t.host_attrs);
 866         transport_container_unregister(&i->rport_attr_cont);
 867
 868         kfree(i);
 869 }
 870 EXPORT_SYMBOL_GPL(srp_release_transport);
 871
 872 static __init int srp_transport_init(void)
 873 {
 874         int ret;
 875
 876         ret = transport_class_register(&srp_host_class);
 877         if (ret)
 878                 return ret;
 879         ret = transport_class_register(&srp_rport_class);
 880         if (ret)
 881                 goto unregister_host_class;
 882
 883         return 0;
 884 unregister_host_class:
 885         transport_class_unregister(&srp_host_class);
 886         return ret;
 887 }
 888
 889 static void __exit srp_transport_exit(void)
 890 {
 891         transport_class_unregister(&srp_host_class);
 892         transport_class_unregister(&srp_rport_class);
 893 }
 894
 895 MODULE_AUTHOR("FUJITA Tomonori");
 896 MODULE_DESCRIPTION("SRP Transport Attributes");
 897 MODULE_LICENSE("GPL");
 898
 899 module_init(srp_transport_init);
 900 module_exit(srp_transport_exit);