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 static int scsi_is_srp_rport(const struct device *dev);
  55
  56 #define to_srp_internal(tmpl) container_of(tmpl, struct srp_internal, t)
  57
  58 #define dev_to_rport(d) container_of(d, struct srp_rport, dev)
  59 #define transport_class_to_srp_rport(dev) dev_to_rport((dev)->parent)
  60 static inline struct Scsi_Host *rport_to_shost(struct srp_rport *r)
  61 {
  62         return dev_to_shost(r->dev.parent);
  63 }
  64
  65 static int find_child_rport(struct device *dev, void *data)
  66 {
  67         struct device **child = data;
  68
  69         if (scsi_is_srp_rport(dev)) {
  70                 WARN_ON_ONCE(*child);
  71                 *child = dev;
  72         }
  73         return 0;
  74 }
  75
  76 static inline struct srp_rport *shost_to_rport(struct Scsi_Host *shost)
  77 {
  78         struct device *child = NULL;
  79
  80         WARN_ON_ONCE(device_for_each_child(&shost->shost_gendev, &child,
  81                                            find_child_rport) < 0);
  82         return child ? dev_to_rport(child) : NULL;
  83 }
  84
  85 /**
  86  * srp_tmo_valid() - check timeout combination validity
  87  * @reconnect_delay: Reconnect delay in seconds.
  88  * @fast_io_fail_tmo: Fast I/O fail timeout in seconds.
  89  * @dev_loss_tmo: Device loss timeout in seconds.
  90  *
  91  * The combination of the timeout parameters must be such that SCSI commands
  92  * are finished in a reasonable time. Hence do not allow the fast I/O fail
  93  * timeout to exceed SCSI_DEVICE_BLOCK_MAX_TIMEOUT nor allow dev_loss_tmo to
  94  * exceed that limit if failing I/O fast has been disabled. Furthermore, these
  95  * parameters must be such that multipath can detect failed paths timely.
  96  * Hence do not allow all three parameters to be disabled simultaneously.
  97  */
  98 int srp_tmo_valid(int reconnect_delay, int fast_io_fail_tmo, long dev_loss_tmo)
  99 {
 100         if (reconnect_delay < 0 && fast_io_fail_tmo < 0 && dev_loss_tmo < 0)
 101                 return -EINVAL;
 102         if (reconnect_delay == 0)
 103                 return -EINVAL;
 104         if (fast_io_fail_tmo > SCSI_DEVICE_BLOCK_MAX_TIMEOUT)
 105                 return -EINVAL;
 106         if (fast_io_fail_tmo < 0 &&
 107             dev_loss_tmo > SCSI_DEVICE_BLOCK_MAX_TIMEOUT)
 108                 return -EINVAL;
 109         if (dev_loss_tmo >= LONG_MAX / HZ)
 110                 return -EINVAL;
 111         if (fast_io_fail_tmo >= 0 && dev_loss_tmo >= 0 &&
 112             fast_io_fail_tmo >= dev_loss_tmo)
 113                 return -EINVAL;
 114         return 0;
 115 }
 116 EXPORT_SYMBOL_GPL(srp_tmo_valid);
 117
 118 static int srp_host_setup(struct transport_container *tc, struct device *dev,
 119                           struct device *cdev)
 120 {
 121         struct Scsi_Host *shost = dev_to_shost(dev);
 122         struct srp_host_attrs *srp_host = to_srp_host_attrs(shost);
 123
 124         atomic_set(&srp_host->next_port_id, 0);
 125         return 0;
 126 }
 127
 128 static DECLARE_TRANSPORT_CLASS(srp_host_class, "srp_host", srp_host_setup,
 129                                NULL, NULL);
 130
 131 static DECLARE_TRANSPORT_CLASS(srp_rport_class, "srp_remote_ports",
 132                                NULL, NULL, NULL);
 133
 134 static ssize_t
 135 show_srp_rport_id(struct device *dev, struct device_attribute *attr,
 136                   char *buf)
 137 {
 138         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 139         return sprintf(buf, "%16phC\n", rport->port_id);
 140 }
 141
 142 static DEVICE_ATTR(port_id, S_IRUGO, show_srp_rport_id, NULL);
 143
 144 static const struct {
 145         u32 value;
 146         char *name;
 147 } srp_rport_role_names[] = {
 148         {SRP_RPORT_ROLE_INITIATOR, "SRP Initiator"},
 149         {SRP_RPORT_ROLE_TARGET, "SRP Target"},
 150 };
 151
 152 static ssize_t
 153 show_srp_rport_roles(struct device *dev, struct device_attribute *attr,
 154                      char *buf)
 155 {
 156         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 157         int i;
 158         char *name = NULL;
 159
 160         for (i = 0; i < ARRAY_SIZE(srp_rport_role_names); i++)
 161                 if (srp_rport_role_names[i].value == rport->roles) {
 162                         name = srp_rport_role_names[i].name;
 163                         break;
 164                 }
 165         return sprintf(buf, "%s\n", name ? : "unknown");
 166 }
 167
 168 static DEVICE_ATTR(roles, S_IRUGO, show_srp_rport_roles, NULL);
 169
 170 static ssize_t store_srp_rport_delete(struct device *dev,
 171                                       struct device_attribute *attr,
 172                                       const char *buf, size_t count)
 173 {
 174         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 175         struct Scsi_Host *shost = dev_to_shost(dev);
 176         struct srp_internal *i = to_srp_internal(shost->transportt);
 177
 178         if (i->f->rport_delete) {
 179                 i->f->rport_delete(rport);
 180                 return count;
 181         } else {
 182                 return -ENOSYS;
 183         }
 184 }
 185
 186 static DEVICE_ATTR(delete, S_IWUSR, NULL, store_srp_rport_delete);
 187
 188 static ssize_t show_srp_rport_state(struct device *dev,
 189                                     struct device_attribute *attr,
 190                                     char *buf)
 191 {
 192         static const char *const state_name[] = {
 193                 [SRP_RPORT_RUNNING]     = "running",
 194                 [SRP_RPORT_BLOCKED]     = "blocked",
 195                 [SRP_RPORT_FAIL_FAST]   = "fail-fast",
 196                 [SRP_RPORT_LOST]        = "lost",
 197         };
 198         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 199         enum srp_rport_state state = rport->state;
 200
 201         return sprintf(buf, "%s\n",
 202                        (unsigned)state < ARRAY_SIZE(state_name) ?
 203                        state_name[state] : "???");
 204 }
 205
 206 static DEVICE_ATTR(state, S_IRUGO, show_srp_rport_state, NULL);
 207
 208 static ssize_t srp_show_tmo(char *buf, int tmo)
 209 {
 210         return tmo >= 0 ? sprintf(buf, "%d\n", tmo) : sprintf(buf, "off\n");
 211 }
 212
 213 int srp_parse_tmo(int *tmo, const char *buf)
 214 {
 215         int res = 0;
 216
 217         if (strncmp(buf, "off", 3) != 0)
 218                 res = kstrtoint(buf, 0, tmo);
 219         else
 220                 *tmo = -1;
 221
 222         return res;
 223 }
 224 EXPORT_SYMBOL(srp_parse_tmo);
 225
 226 static ssize_t show_reconnect_delay(struct device *dev,
 227                                     struct device_attribute *attr, char *buf)
 228 {
 229         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 230
 231         return srp_show_tmo(buf, rport->reconnect_delay);
 232 }
 233
 234 static ssize_t store_reconnect_delay(struct device *dev,
 235                                      struct device_attribute *attr,
 236                                      const char *buf, const size_t count)
 237 {
 238         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 239         int res, delay;
 240
 241         res = srp_parse_tmo(&delay, buf);
 242         if (res)
 243                 goto out;
 244         res = srp_tmo_valid(delay, rport->fast_io_fail_tmo,
 245                             rport->dev_loss_tmo);
 246         if (res)
 247                 goto out;
 248
 249         if (rport->reconnect_delay <= 0 && delay > 0 &&
 250             rport->state != SRP_RPORT_RUNNING) {
 251                 queue_delayed_work(system_long_wq, &rport->reconnect_work,
 252                                    delay * HZ);
 253         } else if (delay <= 0) {
 254                 cancel_delayed_work(&rport->reconnect_work);
 255         }
 256         rport->reconnect_delay = delay;
 257         res = count;
 258
 259 out:
 260         return res;
 261 }
 262
 263 static DEVICE_ATTR(reconnect_delay, S_IRUGO | S_IWUSR, show_reconnect_delay,
 264                    store_reconnect_delay);
 265
 266 static ssize_t show_failed_reconnects(struct device *dev,
 267                                       struct device_attribute *attr, char *buf)
 268 {
 269         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 270
 271         return sprintf(buf, "%d\n", rport->failed_reconnects);
 272 }
 273
 274 static DEVICE_ATTR(failed_reconnects, S_IRUGO, show_failed_reconnects, NULL);
 275
 276 static ssize_t show_srp_rport_fast_io_fail_tmo(struct device *dev,
 277                                                struct device_attribute *attr,
 278                                                char *buf)
 279 {
 280         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 281
 282         return srp_show_tmo(buf, rport->fast_io_fail_tmo);
 283 }
 284
 285 static ssize_t store_srp_rport_fast_io_fail_tmo(struct device *dev,
 286                                                 struct device_attribute *attr,
 287                                                 const char *buf, size_t count)
 288 {
 289         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 290         int res;
 291         int fast_io_fail_tmo;
 292
 293         res = srp_parse_tmo(&fast_io_fail_tmo, buf);
 294         if (res)
 295                 goto out;
 296         res = srp_tmo_valid(rport->reconnect_delay, fast_io_fail_tmo,
 297                             rport->dev_loss_tmo);
 298         if (res)
 299                 goto out;
 300         rport->fast_io_fail_tmo = fast_io_fail_tmo;
 301         res = count;
 302
 303 out:
 304         return res;
 305 }
 306
 307 static DEVICE_ATTR(fast_io_fail_tmo, S_IRUGO | S_IWUSR,
 308                    show_srp_rport_fast_io_fail_tmo,
 309                    store_srp_rport_fast_io_fail_tmo);
 310
 311 static ssize_t show_srp_rport_dev_loss_tmo(struct device *dev,
 312                                            struct device_attribute *attr,
 313                                            char *buf)
 314 {
 315         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 316
 317         return srp_show_tmo(buf, rport->dev_loss_tmo);
 318 }
 319
 320 static ssize_t store_srp_rport_dev_loss_tmo(struct device *dev,
 321                                             struct device_attribute *attr,
 322                                             const char *buf, size_t count)
 323 {
 324         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 325         int res;
 326         int dev_loss_tmo;
 327
 328         res = srp_parse_tmo(&dev_loss_tmo, buf);
 329         if (res)
 330                 goto out;
 331         res = srp_tmo_valid(rport->reconnect_delay, rport->fast_io_fail_tmo,
 332                             dev_loss_tmo);
 333         if (res)
 334                 goto out;
 335         rport->dev_loss_tmo = dev_loss_tmo;
 336         res = count;
 337
 338 out:
 339         return res;
 340 }
 341
 342 static DEVICE_ATTR(dev_loss_tmo, S_IRUGO | S_IWUSR,
 343                    show_srp_rport_dev_loss_tmo,
 344                    store_srp_rport_dev_loss_tmo);
 345
 346 static int srp_rport_set_state(struct srp_rport *rport,
 347                                enum srp_rport_state new_state)
 348 {
 349         enum srp_rport_state old_state = rport->state;
 350
 351         lockdep_assert_held(&rport->mutex);
 352
 353         switch (new_state) {
 354         case SRP_RPORT_RUNNING:
 355                 switch (old_state) {
 356                 case SRP_RPORT_LOST:
 357                         goto invalid;
 358                 default:
 359                         break;
 360                 }
 361                 break;
 362         case SRP_RPORT_BLOCKED:
 363                 switch (old_state) {
 364                 case SRP_RPORT_RUNNING:
 365                         break;
 366                 default:
 367                         goto invalid;
 368                 }
 369                 break;
 370         case SRP_RPORT_FAIL_FAST:
 371                 switch (old_state) {
 372                 case SRP_RPORT_LOST:
 373                         goto invalid;
 374                 default:
 375                         break;
 376                 }
 377                 break;
 378         case SRP_RPORT_LOST:
 379                 break;
 380         }
 381         rport->state = new_state;
 382         return 0;
 383
 384 invalid:
 385         return -EINVAL;
 386 }
 387
 388 /**
 389  * srp_reconnect_work() - reconnect and schedule a new attempt if necessary
 390  * @work: Work structure used for scheduling this operation.
 391  */
 392 static void srp_reconnect_work(struct work_struct *work)
 393 {
 394         struct srp_rport *rport = container_of(to_delayed_work(work),
 395                                         struct srp_rport, reconnect_work);
 396         struct Scsi_Host *shost = rport_to_shost(rport);
 397         int delay, res;
 398
 399         res = srp_reconnect_rport(rport);
 400         if (res != 0) {
 401                 shost_printk(KERN_ERR, shost,
 402                              "reconnect attempt %d failed (%d)\n",
 403                              ++rport->failed_reconnects, res);
 404                 delay = rport->reconnect_delay *
 405                         min(100, max(1, rport->failed_reconnects - 10));
 406                 if (delay > 0)
 407                         queue_delayed_work(system_long_wq,
 408                                            &rport->reconnect_work, delay * HZ);
 409         }
 410 }
 411
 412 static void __rport_fail_io_fast(struct srp_rport *rport)
 413 {
 414         struct Scsi_Host *shost = rport_to_shost(rport);
 415         struct srp_internal *i;
 416
 417         lockdep_assert_held(&rport->mutex);
 418
 419         if (srp_rport_set_state(rport, SRP_RPORT_FAIL_FAST))
 420                 return;
 421         /*
 422          * Call scsi_target_block() to wait for ongoing shost->queuecommand()
 423          * calls before invoking i->f->terminate_rport_io().
 424          */
 425         scsi_target_block(rport->dev.parent);
 426         scsi_target_unblock(rport->dev.parent, SDEV_TRANSPORT_OFFLINE);
 427
 428         /* Involve the LLD if possible to terminate all I/O on the rport. */
 429         i = to_srp_internal(shost->transportt);
 430         if (i->f->terminate_rport_io)
 431                 i->f->terminate_rport_io(rport);
 432 }
 433
 434 /**
 435  * rport_fast_io_fail_timedout() - fast I/O failure timeout handler
 436  * @work: Work structure used for scheduling this operation.
 437  */
 438 static void rport_fast_io_fail_timedout(struct work_struct *work)
 439 {
 440         struct srp_rport *rport = container_of(to_delayed_work(work),
 441                                         struct srp_rport, fast_io_fail_work);
 442         struct Scsi_Host *shost = rport_to_shost(rport);
 443
 444         pr_info("fast_io_fail_tmo expired for SRP %s / %s.\n",
 445                 dev_name(&rport->dev), dev_name(&shost->shost_gendev));
 446
 447         mutex_lock(&rport->mutex);
 448         if (rport->state == SRP_RPORT_BLOCKED)
 449                 __rport_fail_io_fast(rport);
 450         mutex_unlock(&rport->mutex);
 451 }
 452
 453 /**
 454  * rport_dev_loss_timedout() - device loss timeout handler
 455  * @work: Work structure used for scheduling this operation.
 456  */
 457 static void rport_dev_loss_timedout(struct work_struct *work)
 458 {
 459         struct srp_rport *rport = container_of(to_delayed_work(work),
 460                                         struct srp_rport, dev_loss_work);
 461         struct Scsi_Host *shost = rport_to_shost(rport);
 462         struct srp_internal *i = to_srp_internal(shost->transportt);
 463
 464         pr_info("dev_loss_tmo expired for SRP %s / %s.\n",
 465                 dev_name(&rport->dev), dev_name(&shost->shost_gendev));
 466
 467         mutex_lock(&rport->mutex);
 468         WARN_ON(srp_rport_set_state(rport, SRP_RPORT_LOST) != 0);
 469         scsi_target_unblock(rport->dev.parent, SDEV_TRANSPORT_OFFLINE);
 470         mutex_unlock(&rport->mutex);
 471
 472         i->f->rport_delete(rport);
 473 }
 474
 475 static void __srp_start_tl_fail_timers(struct srp_rport *rport)
 476 {
 477         struct Scsi_Host *shost = rport_to_shost(rport);
 478         int delay, fast_io_fail_tmo, dev_loss_tmo;
 479
 480         lockdep_assert_held(&rport->mutex);
 481
 482         delay = rport->reconnect_delay;
 483         fast_io_fail_tmo = rport->fast_io_fail_tmo;
 484         dev_loss_tmo = rport->dev_loss_tmo;
 485         pr_debug("%s current state: %d\n", dev_name(&shost->shost_gendev),
 486                  rport->state);
 487
 488         if (rport->state == SRP_RPORT_LOST)
 489                 return;
 490         if (delay > 0)
 491                 queue_delayed_work(system_long_wq, &rport->reconnect_work,
 492                                    1UL * delay * HZ);
 493         if ((fast_io_fail_tmo >= 0 || dev_loss_tmo >= 0) &&
 494             srp_rport_set_state(rport, SRP_RPORT_BLOCKED) == 0) {
 495                 pr_debug("%s new state: %d\n", dev_name(&shost->shost_gendev),
 496                          rport->state);
 497                 scsi_target_block(&shost->shost_gendev);
 498                 if (fast_io_fail_tmo >= 0)
 499                         queue_delayed_work(system_long_wq,
 500                                            &rport->fast_io_fail_work,
 501                                            1UL * fast_io_fail_tmo * HZ);
 502                 if (dev_loss_tmo >= 0)
 503                         queue_delayed_work(system_long_wq,
 504                                            &rport->dev_loss_work,
 505                                            1UL * dev_loss_tmo * HZ);
 506         }
 507 }
 508
 509 /**
 510  * srp_start_tl_fail_timers() - start the transport layer failure timers
 511  * @rport: SRP target port.
 512  *
 513  * Start the transport layer fast I/O failure and device loss timers. Do not
 514  * modify a timer that was already started.
 515  */
 516 void srp_start_tl_fail_timers(struct srp_rport *rport)
 517 {
 518         mutex_lock(&rport->mutex);
 519         __srp_start_tl_fail_timers(rport);
 520         mutex_unlock(&rport->mutex);
 521 }
 522 EXPORT_SYMBOL(srp_start_tl_fail_timers);
 523
 524 /**
 525  * srp_reconnect_rport() - reconnect to an SRP target port
 526  * @rport: SRP target port.
 527  *
 528  * Blocks SCSI command queueing before invoking reconnect() such that
 529  * queuecommand() won't be invoked concurrently with reconnect() from outside
 530  * the SCSI EH. This is important since a reconnect() implementation may
 531  * reallocate resources needed by queuecommand().
 532  *
 533  * Notes:
 534  * - This function neither waits until outstanding requests have finished nor
 535  *   tries to abort these. It is the responsibility of the reconnect()
 536  *   function to finish outstanding commands before reconnecting to the target
 537  *   port.
 538  * - It is the responsibility of the caller to ensure that the resources
 539  *   reallocated by the reconnect() function won't be used while this function
 540  *   is in progress. One possible strategy is to invoke this function from
 541  *   the context of the SCSI EH thread only. Another possible strategy is to
 542  *   lock the rport mutex inside each SCSI LLD callback that can be invoked by
 543  *   the SCSI EH (the scsi_host_template.eh_*() functions and also the
 544  *   scsi_host_template.queuecommand() function).
 545  */
 546 int srp_reconnect_rport(struct srp_rport *rport)
 547 {
 548         struct Scsi_Host *shost = rport_to_shost(rport);
 549         struct srp_internal *i = to_srp_internal(shost->transportt);
 550         struct scsi_device *sdev;
 551         int res;
 552
 553         pr_debug("SCSI host %s\n", dev_name(&shost->shost_gendev));
 554
 555         res = mutex_lock_interruptible(&rport->mutex);
 556         if (res)
 557                 goto out;
 558         scsi_target_block(&shost->shost_gendev);
 559         res = rport->state != SRP_RPORT_LOST ? i->f->reconnect(rport) : -ENODEV;
 560         pr_debug("%s (state %d): transport.reconnect() returned %d\n",
 561                  dev_name(&shost->shost_gendev), rport->state, res);
 562         if (res == 0) {
 563                 cancel_delayed_work(&rport->fast_io_fail_work);
 564                 cancel_delayed_work(&rport->dev_loss_work);
 565
 566                 rport->failed_reconnects = 0;
 567                 srp_rport_set_state(rport, SRP_RPORT_RUNNING);
 568                 scsi_target_unblock(&shost->shost_gendev, SDEV_RUNNING);
 569                 /*
 570                  * If the SCSI error handler has offlined one or more devices,
 571                  * invoking scsi_target_unblock() won't change the state of
 572                  * these devices into running so do that explicitly.
 573                  */
 574                 shost_for_each_device(sdev, shost) {
 575                         mutex_lock(&sdev->state_mutex);
 576                         if (sdev->sdev_state == SDEV_OFFLINE)
 577                                 sdev->sdev_state = SDEV_RUNNING;
 578                         mutex_unlock(&sdev->state_mutex);
 579                 }
 580         } else if (rport->state == SRP_RPORT_RUNNING) {
 581                 /*
 582                  * srp_reconnect_rport() has been invoked with fast_io_fail
 583                  * and dev_loss off. Mark the port as failed and start the TL
 584                  * failure timers if these had not yet been started.
 585                  */
 586                 __rport_fail_io_fast(rport);
 587                 scsi_target_unblock(&shost->shost_gendev,
 588                                     SDEV_TRANSPORT_OFFLINE);
 589                 __srp_start_tl_fail_timers(rport);
 590         } else if (rport->state != SRP_RPORT_BLOCKED) {
 591                 scsi_target_unblock(&shost->shost_gendev,
 592                                     SDEV_TRANSPORT_OFFLINE);
 593         }
 594         mutex_unlock(&rport->mutex);
 595
 596 out:
 597         return res;
 598 }
 599 EXPORT_SYMBOL(srp_reconnect_rport);
 600
 601 /**
 602  * srp_timed_out() - SRP transport intercept of the SCSI timeout EH
 603  * @scmd: SCSI command.
 604  *
 605  * If a timeout occurs while an rport is in the blocked state, ask the SCSI
 606  * EH to continue waiting (BLK_EH_RESET_TIMER). Otherwise let the SCSI core
 607  * handle the timeout (BLK_EH_DONE).
 608  *
 609  * Note: This function is called from soft-IRQ context and with the request
 610  * queue lock held.
 611  */
 612 enum blk_eh_timer_return srp_timed_out(struct scsi_cmnd *scmd)
 613 {
 614         struct scsi_device *sdev = scmd->device;
 615         struct Scsi_Host *shost = sdev->host;
 616         struct srp_internal *i = to_srp_internal(shost->transportt);
 617         struct srp_rport *rport = shost_to_rport(shost);
 618
 619         pr_debug("timeout for sdev %s\n", dev_name(&sdev->sdev_gendev));
 620         return rport && rport->fast_io_fail_tmo < 0 &&
 621                 rport->dev_loss_tmo < 0 &&
 622                 i->f->reset_timer_if_blocked && scsi_device_blocked(sdev) ?
 623                 BLK_EH_RESET_TIMER : BLK_EH_DONE;
 624 }
 625 EXPORT_SYMBOL(srp_timed_out);
 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 /**
 817  * srp_attach_transport  -  instantiate SRP transport template
 818  * @ft:         SRP transport class function template
 819  */
 820 struct scsi_transport_template *
 821 srp_attach_transport(struct srp_function_template *ft)
 822 {
 823         int count;
 824         struct srp_internal *i;
 825
 826         i = kzalloc(sizeof(*i), GFP_KERNEL);
 827         if (!i)
 828                 return NULL;
 829
 830         i->t.host_size = sizeof(struct srp_host_attrs);
 831         i->t.host_attrs.ac.attrs = &i->host_attrs[0];
 832         i->t.host_attrs.ac.class = &srp_host_class.class;
 833         i->t.host_attrs.ac.match = srp_host_match;
 834         i->host_attrs[0] = NULL;
 835         transport_container_register(&i->t.host_attrs);
 836
 837         i->rport_attr_cont.ac.attrs = &i->rport_attrs[0];
 838         i->rport_attr_cont.ac.class = &srp_rport_class.class;
 839         i->rport_attr_cont.ac.match = srp_rport_match;
 840
 841         count = 0;
 842         i->rport_attrs[count++] = &dev_attr_port_id;
 843         i->rport_attrs[count++] = &dev_attr_roles;
 844         if (ft->has_rport_state) {
 845                 i->rport_attrs[count++] = &dev_attr_state;
 846                 i->rport_attrs[count++] = &dev_attr_fast_io_fail_tmo;
 847                 i->rport_attrs[count++] = &dev_attr_dev_loss_tmo;
 848         }
 849         if (ft->reconnect) {
 850                 i->rport_attrs[count++] = &dev_attr_reconnect_delay;
 851                 i->rport_attrs[count++] = &dev_attr_failed_reconnects;
 852         }
 853         if (ft->rport_delete)
 854                 i->rport_attrs[count++] = &dev_attr_delete;
 855         i->rport_attrs[count++] = NULL;
 856         BUG_ON(count > ARRAY_SIZE(i->rport_attrs));
 857
 858         transport_container_register(&i->rport_attr_cont);
 859
 860         i->f = ft;
 861
 862         return &i->t;
 863 }
 864 EXPORT_SYMBOL_GPL(srp_attach_transport);
 865
 866 /**
 867  * srp_release_transport  -  release SRP transport template instance
 868  * @t:          transport template instance
 869  */
 870 void srp_release_transport(struct scsi_transport_template *t)
 871 {
 872         struct srp_internal *i = to_srp_internal(t);
 873
 874         transport_container_unregister(&i->t.host_attrs);
 875         transport_container_unregister(&i->rport_attr_cont);
 876
 877         kfree(i);
 878 }
 879 EXPORT_SYMBOL_GPL(srp_release_transport);
 880
 881 static __init int srp_transport_init(void)
 882 {
 883         int ret;
 884
 885         ret = transport_class_register(&srp_host_class);
 886         if (ret)
 887                 return ret;
 888         ret = transport_class_register(&srp_rport_class);
 889         if (ret)
 890                 goto unregister_host_class;
 891
 892         return 0;
 893 unregister_host_class:
 894         transport_class_unregister(&srp_host_class);
 895         return ret;
 896 }
 897
 898 static void __exit srp_transport_exit(void)
 899 {
 900         transport_class_unregister(&srp_host_class);
 901         transport_class_unregister(&srp_rport_class);
 902 }
 903
 904 MODULE_AUTHOR("FUJITA Tomonori");
 905 MODULE_DESCRIPTION("SRP Transport Attributes");
 906 MODULE_LICENSE("GPL");
 907
 908 module_init(srp_transport_init);
 909 module_exit(srp_transport_exit);