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