drivers/scsi/scsi_transport_srp.c

   1 /*
   2  * SCSI RDMA (SRP) transport class
   3  *
   4  * Copyright (C) 2007 FUJITA Tomonori <tomof@acm.org>
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License as
   8  * published by the Free Software Foundation, version 2 of the
   9  * License.
  10  *
  11  * This program is distributed in the hope that it will be useful, but
  12  * WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14  * General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
  19  * 02110-1301 USA
  20  */
  21 #include <linux/init.h>
  22 #include <linux/module.h>
  23 #include <linux/jiffies.h>
  24 #include <linux/err.h>
  25 #include <linux/slab.h>
  26 #include <linux/string.h>
  27 #include <linux/delay.h>
  28
  29 #include <scsi/scsi.h>
  30 #include <scsi/scsi_cmnd.h>
  31 #include <scsi/scsi_device.h>
  32 #include <scsi/scsi_host.h>
  33 #include <scsi/scsi_transport.h>
  34 #include <scsi/scsi_transport_srp.h>
  35 #include "scsi_priv.h"
  36
  37 struct srp_host_attrs {
  38         atomic_t next_port_id;
  39 };
  40 #define to_srp_host_attrs(host) ((struct srp_host_attrs *)(host)->shost_data)
  41
  42 #define SRP_HOST_ATTRS 0
  43 #define SRP_RPORT_ATTRS 8
  44
  45 struct srp_internal {
  46         struct scsi_transport_template t;
  47         struct srp_function_template *f;
  48
  49         struct device_attribute *host_attrs[SRP_HOST_ATTRS + 1];
  50
  51         struct device_attribute *rport_attrs[SRP_RPORT_ATTRS + 1];
  52         struct transport_container rport_attr_cont;
  53 };
  54
  55 #define to_srp_internal(tmpl) container_of(tmpl, struct srp_internal, t)
  56
  57 #define dev_to_rport(d) container_of(d, struct srp_rport, dev)
  58 #define transport_class_to_srp_rport(dev) dev_to_rport((dev)->parent)
  59 static inline struct Scsi_Host *rport_to_shost(struct srp_rport *r)
  60 {
  61         return dev_to_shost(r->dev.parent);
  62 }
  63
  64 static inline struct srp_rport *shost_to_rport(struct Scsi_Host *shost)
  65 {
  66         return transport_class_to_srp_rport(&shost->shost_gendev);
  67 }
  68
  69 /**
  70  * srp_tmo_valid() - check timeout combination validity
  71  * @reconnect_delay: Reconnect delay in seconds.
  72  * @fast_io_fail_tmo: Fast I/O fail timeout in seconds.
  73  * @dev_loss_tmo: Device loss timeout in seconds.
  74  *
  75  * The combination of the timeout parameters must be such that SCSI commands
  76  * are finished in a reasonable time. Hence do not allow the fast I/O fail
  77  * timeout to exceed SCSI_DEVICE_BLOCK_MAX_TIMEOUT nor allow dev_loss_tmo to
  78  * exceed that limit if failing I/O fast has been disabled. Furthermore, these
  79  * parameters must be such that multipath can detect failed paths timely.
  80  * Hence do not allow all three parameters to be disabled simultaneously.
  81  */
  82 int srp_tmo_valid(int reconnect_delay, int fast_io_fail_tmo, int dev_loss_tmo)
  83 {
  84         if (reconnect_delay < 0 && fast_io_fail_tmo < 0 && dev_loss_tmo < 0)
  85                 return -EINVAL;
  86         if (reconnect_delay == 0)
  87                 return -EINVAL;
  88         if (fast_io_fail_tmo > SCSI_DEVICE_BLOCK_MAX_TIMEOUT)
  89                 return -EINVAL;
  90         if (fast_io_fail_tmo < 0 &&
  91             dev_loss_tmo > SCSI_DEVICE_BLOCK_MAX_TIMEOUT)
  92                 return -EINVAL;
  93         if (dev_loss_tmo >= LONG_MAX / HZ)
  94                 return -EINVAL;
  95         if (fast_io_fail_tmo >= 0 && dev_loss_tmo >= 0 &&
  96             fast_io_fail_tmo >= dev_loss_tmo)
  97                 return -EINVAL;
  98         return 0;
  99 }
 100 EXPORT_SYMBOL_GPL(srp_tmo_valid);
 101
 102 static int srp_host_setup(struct transport_container *tc, struct device *dev,
 103                           struct device *cdev)
 104 {
 105         struct Scsi_Host *shost = dev_to_shost(dev);
 106         struct srp_host_attrs *srp_host = to_srp_host_attrs(shost);
 107
 108         atomic_set(&srp_host->next_port_id, 0);
 109         return 0;
 110 }
 111
 112 static DECLARE_TRANSPORT_CLASS(srp_host_class, "srp_host", srp_host_setup,
 113                                NULL, NULL);
 114
 115 static DECLARE_TRANSPORT_CLASS(srp_rport_class, "srp_remote_ports",
 116                                NULL, NULL, NULL);
 117
 118 #define SRP_PID(p) \
 119         (p)->port_id[0], (p)->port_id[1], (p)->port_id[2], (p)->port_id[3], \
 120         (p)->port_id[4], (p)->port_id[5], (p)->port_id[6], (p)->port_id[7], \
 121         (p)->port_id[8], (p)->port_id[9], (p)->port_id[10], (p)->port_id[11], \
 122         (p)->port_id[12], (p)->port_id[13], (p)->port_id[14], (p)->port_id[15]
 123
 124 #define SRP_PID_FMT "%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:" \
 125         "%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x"
 126
 127 static ssize_t
 128 show_srp_rport_id(struct device *dev, struct device_attribute *attr,
 129                   char *buf)
 130 {
 131         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 132         return sprintf(buf, SRP_PID_FMT "\n", SRP_PID(rport));
 133 }
 134
 135 static DEVICE_ATTR(port_id, S_IRUGO, show_srp_rport_id, NULL);
 136
 137 static const struct {
 138         u32 value;
 139         char *name;
 140 } srp_rport_role_names[] = {
 141         {SRP_RPORT_ROLE_INITIATOR, "SRP Initiator"},
 142         {SRP_RPORT_ROLE_TARGET, "SRP Target"},
 143 };
 144
 145 static ssize_t
 146 show_srp_rport_roles(struct device *dev, struct device_attribute *attr,
 147                      char *buf)
 148 {
 149         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 150         int i;
 151         char *name = NULL;
 152
 153         for (i = 0; i < ARRAY_SIZE(srp_rport_role_names); i++)
 154                 if (srp_rport_role_names[i].value == rport->roles) {
 155                         name = srp_rport_role_names[i].name;
 156                         break;
 157                 }
 158         return sprintf(buf, "%s\n", name ? : "unknown");
 159 }
 160
 161 static DEVICE_ATTR(roles, S_IRUGO, show_srp_rport_roles, NULL);
 162
 163 static ssize_t store_srp_rport_delete(struct device *dev,
 164                                       struct device_attribute *attr,
 165                                       const char *buf, size_t count)
 166 {
 167         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 168         struct Scsi_Host *shost = dev_to_shost(dev);
 169         struct srp_internal *i = to_srp_internal(shost->transportt);
 170
 171         if (i->f->rport_delete) {
 172                 i->f->rport_delete(rport);
 173                 return count;
 174         } else {
 175                 return -ENOSYS;
 176         }
 177 }
 178
 179 static DEVICE_ATTR(delete, S_IWUSR, NULL, store_srp_rport_delete);
 180
 181 static ssize_t show_srp_rport_state(struct device *dev,
 182                                     struct device_attribute *attr,
 183                                     char *buf)
 184 {
 185         static const char *const state_name[] = {
 186                 [SRP_RPORT_RUNNING]     = "running",
 187                 [SRP_RPORT_BLOCKED]     = "blocked",
 188                 [SRP_RPORT_FAIL_FAST]   = "fail-fast",
 189                 [SRP_RPORT_LOST]        = "lost",
 190         };
 191         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 192         enum srp_rport_state state = rport->state;
 193
 194         return sprintf(buf, "%s\n",
 195                        (unsigned)state < ARRAY_SIZE(state_name) ?
 196                        state_name[state] : "???");
 197 }
 198
 199 static DEVICE_ATTR(state, S_IRUGO, show_srp_rport_state, NULL);
 200
 201 static ssize_t srp_show_tmo(char *buf, int tmo)
 202 {
 203         return tmo >= 0 ? sprintf(buf, "%d\n", tmo) : sprintf(buf, "off\n");
 204 }
 205
 206 int srp_parse_tmo(int *tmo, const char *buf)
 207 {
 208         int res = 0;
 209
 210         if (strncmp(buf, "off", 3) != 0)
 211                 res = kstrtoint(buf, 0, tmo);
 212         else
 213                 *tmo = -1;
 214
 215         return res;
 216 }
 217 EXPORT_SYMBOL(srp_parse_tmo);
 218
 219 static ssize_t show_reconnect_delay(struct device *dev,
 220                                     struct device_attribute *attr, char *buf)
 221 {
 222         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 223
 224         return srp_show_tmo(buf, rport->reconnect_delay);
 225 }
 226
 227 static ssize_t store_reconnect_delay(struct device *dev,
 228                                      struct device_attribute *attr,
 229                                      const char *buf, const size_t count)
 230 {
 231         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 232         int res, delay;
 233
 234         res = srp_parse_tmo(&delay, buf);
 235         if (res)
 236                 goto out;
 237         res = srp_tmo_valid(delay, rport->fast_io_fail_tmo,
 238                             rport->dev_loss_tmo);
 239         if (res)
 240                 goto out;
 241
 242         if (rport->reconnect_delay <= 0 && delay > 0 &&
 243             rport->state != SRP_RPORT_RUNNING) {
 244                 queue_delayed_work(system_long_wq, &rport->reconnect_work,
 245                                    delay * HZ);
 246         } else if (delay <= 0) {
 247                 cancel_delayed_work(&rport->reconnect_work);
 248         }
 249         rport->reconnect_delay = delay;
 250         res = count;
 251
 252 out:
 253         return res;
 254 }
 255
 256 static DEVICE_ATTR(reconnect_delay, S_IRUGO | S_IWUSR, show_reconnect_delay,
 257                    store_reconnect_delay);
 258
 259 static ssize_t show_failed_reconnects(struct device *dev,
 260                                       struct device_attribute *attr, char *buf)
 261 {
 262         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 263
 264         return sprintf(buf, "%d\n", rport->failed_reconnects);
 265 }
 266
 267 static DEVICE_ATTR(failed_reconnects, S_IRUGO, show_failed_reconnects, NULL);
 268
 269 static ssize_t show_srp_rport_fast_io_fail_tmo(struct device *dev,
 270                                                struct device_attribute *attr,
 271                                                char *buf)
 272 {
 273         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 274
 275         return srp_show_tmo(buf, rport->fast_io_fail_tmo);
 276 }
 277
 278 static ssize_t store_srp_rport_fast_io_fail_tmo(struct device *dev,
 279                                                 struct device_attribute *attr,
 280                                                 const char *buf, size_t count)
 281 {
 282         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 283         int res;
 284         int fast_io_fail_tmo;
 285
 286         res = srp_parse_tmo(&fast_io_fail_tmo, buf);
 287         if (res)
 288                 goto out;
 289         res = srp_tmo_valid(rport->reconnect_delay, fast_io_fail_tmo,
 290                             rport->dev_loss_tmo);
 291         if (res)
 292                 goto out;
 293         rport->fast_io_fail_tmo = fast_io_fail_tmo;
 294         res = count;
 295
 296 out:
 297         return res;
 298 }
 299
 300 static DEVICE_ATTR(fast_io_fail_tmo, S_IRUGO | S_IWUSR,
 301                    show_srp_rport_fast_io_fail_tmo,
 302                    store_srp_rport_fast_io_fail_tmo);
 303
 304 static ssize_t show_srp_rport_dev_loss_tmo(struct device *dev,
 305                                            struct device_attribute *attr,
 306                                            char *buf)
 307 {
 308         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 309
 310         return srp_show_tmo(buf, rport->dev_loss_tmo);
 311 }
 312
 313 static ssize_t store_srp_rport_dev_loss_tmo(struct device *dev,
 314                                             struct device_attribute *attr,
 315                                             const char *buf, size_t count)
 316 {
 317         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 318         int res;
 319         int dev_loss_tmo;
 320
 321         res = srp_parse_tmo(&dev_loss_tmo, buf);
 322         if (res)
 323                 goto out;
 324         res = srp_tmo_valid(rport->reconnect_delay, rport->fast_io_fail_tmo,
 325                             dev_loss_tmo);
 326         if (res)
 327                 goto out;
 328         rport->dev_loss_tmo = dev_loss_tmo;
 329         res = count;
 330
 331 out:
 332         return res;
 333 }
 334
 335 static DEVICE_ATTR(dev_loss_tmo, S_IRUGO | S_IWUSR,
 336                    show_srp_rport_dev_loss_tmo,
 337                    store_srp_rport_dev_loss_tmo);
 338
 339 static int srp_rport_set_state(struct srp_rport *rport,
 340                                enum srp_rport_state new_state)
 341 {
 342         enum srp_rport_state old_state = rport->state;
 343
 344         lockdep_assert_held(&rport->mutex);
 345
 346         switch (new_state) {
 347         case SRP_RPORT_RUNNING:
 348                 switch (old_state) {
 349                 case SRP_RPORT_LOST:
 350                         goto invalid;
 351                 default:
 352                         break;
 353                 }
 354                 break;
 355         case SRP_RPORT_BLOCKED:
 356                 switch (old_state) {
 357                 case SRP_RPORT_RUNNING:
 358                         break;
 359                 default:
 360                         goto invalid;
 361                 }
 362                 break;
 363         case SRP_RPORT_FAIL_FAST:
 364                 switch (old_state) {
 365                 case SRP_RPORT_LOST:
 366                         goto invalid;
 367                 default:
 368                         break;
 369                 }
 370                 break;
 371         case SRP_RPORT_LOST:
 372                 break;
 373         }
 374         rport->state = new_state;
 375         return 0;
 376
 377 invalid:
 378         return -EINVAL;
 379 }
 380
 381 /**
 382  * srp_reconnect_work() - reconnect and schedule a new attempt if necessary
 383  * @work: Work structure used for scheduling this operation.
 384  */
 385 static void srp_reconnect_work(struct work_struct *work)
 386 {
 387         struct srp_rport *rport = container_of(to_delayed_work(work),
 388                                         struct srp_rport, reconnect_work);
 389         struct Scsi_Host *shost = rport_to_shost(rport);
 390         int delay, res;
 391
 392         res = srp_reconnect_rport(rport);
 393         if (res != 0) {
 394                 shost_printk(KERN_ERR, shost,
 395                              "reconnect attempt %d failed (%d)\n",
 396                              ++rport->failed_reconnects, res);
 397                 delay = rport->reconnect_delay *
 398                         min(100, max(1, rport->failed_reconnects - 10));
 399                 if (delay > 0)
 400                         queue_delayed_work(system_long_wq,
 401                                            &rport->reconnect_work, delay * HZ);
 402         }
 403 }
 404
 405 /**
 406  * scsi_request_fn_active() - number of kernel threads inside scsi_request_fn()
 407  * @shost: SCSI host for which to count the number of scsi_request_fn() callers.
 408  *
 409  * To do: add support for scsi-mq in this function.
 410  */
 411 static int scsi_request_fn_active(struct Scsi_Host *shost)
 412 {
 413         struct scsi_device *sdev;
 414         struct request_queue *q;
 415         int request_fn_active = 0;
 416
 417         shost_for_each_device(sdev, shost) {
 418                 q = sdev->request_queue;
 419
 420                 spin_lock_irq(q->queue_lock);
 421                 request_fn_active += q->request_fn_active;
 422                 spin_unlock_irq(q->queue_lock);
 423         }
 424
 425         return request_fn_active;
 426 }
 427
 428 /* Wait until ongoing shost->hostt->queuecommand() calls have finished. */
 429 static void srp_wait_for_queuecommand(struct Scsi_Host *shost)
 430 {
 431         while (scsi_request_fn_active(shost))
 432                 msleep(20);
 433 }
 434
 435 static void __rport_fail_io_fast(struct srp_rport *rport)
 436 {
 437         struct Scsi_Host *shost = rport_to_shost(rport);
 438         struct srp_internal *i;
 439
 440         lockdep_assert_held(&rport->mutex);
 441
 442         if (srp_rport_set_state(rport, SRP_RPORT_FAIL_FAST))
 443                 return;
 444         scsi_target_unblock(rport->dev.parent, SDEV_TRANSPORT_OFFLINE);
 445
 446         /* Involve the LLD if possible to terminate all I/O on the rport. */
 447         i = to_srp_internal(shost->transportt);
 448         if (i->f->terminate_rport_io) {
 449                 srp_wait_for_queuecommand(shost);
 450                 i->f->terminate_rport_io(rport);
 451         }
 452 }
 453
 454 /**
 455  * rport_fast_io_fail_timedout() - fast I/O failure timeout handler
 456  * @work: Work structure used for scheduling this operation.
 457  */
 458 static void rport_fast_io_fail_timedout(struct work_struct *work)
 459 {
 460         struct srp_rport *rport = container_of(to_delayed_work(work),
 461                                         struct srp_rport, fast_io_fail_work);
 462         struct Scsi_Host *shost = rport_to_shost(rport);
 463
 464         pr_info("fast_io_fail_tmo expired for SRP %s / %s.\n",
 465                 dev_name(&rport->dev), dev_name(&shost->shost_gendev));
 466
 467         mutex_lock(&rport->mutex);
 468         if (rport->state == SRP_RPORT_BLOCKED)
 469                 __rport_fail_io_fast(rport);
 470         mutex_unlock(&rport->mutex);
 471 }
 472
 473 /**
 474  * rport_dev_loss_timedout() - device loss timeout handler
 475  * @work: Work structure used for scheduling this operation.
 476  */
 477 static void rport_dev_loss_timedout(struct work_struct *work)
 478 {
 479         struct srp_rport *rport = container_of(to_delayed_work(work),
 480                                         struct srp_rport, dev_loss_work);
 481         struct Scsi_Host *shost = rport_to_shost(rport);
 482         struct srp_internal *i = to_srp_internal(shost->transportt);
 483
 484         pr_info("dev_loss_tmo expired for SRP %s / %s.\n",
 485                 dev_name(&rport->dev), dev_name(&shost->shost_gendev));
 486
 487         mutex_lock(&rport->mutex);
 488         WARN_ON(srp_rport_set_state(rport, SRP_RPORT_LOST) != 0);
 489         scsi_target_unblock(rport->dev.parent, SDEV_TRANSPORT_OFFLINE);
 490         mutex_unlock(&rport->mutex);
 491
 492         i->f->rport_delete(rport);
 493 }
 494
 495 static void __srp_start_tl_fail_timers(struct srp_rport *rport)
 496 {
 497         struct Scsi_Host *shost = rport_to_shost(rport);
 498         int delay, fast_io_fail_tmo, dev_loss_tmo;
 499
 500         lockdep_assert_held(&rport->mutex);
 501
 502         delay = rport->reconnect_delay;
 503         fast_io_fail_tmo = rport->fast_io_fail_tmo;
 504         dev_loss_tmo = rport->dev_loss_tmo;
 505         pr_debug("%s current state: %d\n", dev_name(&shost->shost_gendev),
 506                  rport->state);
 507
 508         if (rport->state == SRP_RPORT_LOST)
 509                 return;
 510         if (delay > 0)
 511                 queue_delayed_work(system_long_wq, &rport->reconnect_work,
 512                                    1UL * delay * HZ);
 513         if ((fast_io_fail_tmo >= 0 || dev_loss_tmo >= 0) &&
 514             srp_rport_set_state(rport, SRP_RPORT_BLOCKED) == 0) {
 515                 pr_debug("%s new state: %d\n", dev_name(&shost->shost_gendev),
 516                          rport->state);
 517                 scsi_target_block(&shost->shost_gendev);
 518                 if (fast_io_fail_tmo >= 0)
 519                         queue_delayed_work(system_long_wq,
 520                                            &rport->fast_io_fail_work,
 521                                            1UL * fast_io_fail_tmo * HZ);
 522                 if (dev_loss_tmo >= 0)
 523                         queue_delayed_work(system_long_wq,
 524                                            &rport->dev_loss_work,
 525                                            1UL * dev_loss_tmo * HZ);
 526         }
 527 }
 528
 529 /**
 530  * srp_start_tl_fail_timers() - start the transport layer failure timers
 531  * @rport: SRP target port.
 532  *
 533  * Start the transport layer fast I/O failure and device loss timers. Do not
 534  * modify a timer that was already started.
 535  */
 536 void srp_start_tl_fail_timers(struct srp_rport *rport)
 537 {
 538         mutex_lock(&rport->mutex);
 539         __srp_start_tl_fail_timers(rport);
 540         mutex_unlock(&rport->mutex);
 541 }
 542 EXPORT_SYMBOL(srp_start_tl_fail_timers);
 543
 544 /**
 545  * srp_reconnect_rport() - reconnect to an SRP target port
 546  * @rport: SRP target port.
 547  *
 548  * Blocks SCSI command queueing before invoking reconnect() such that
 549  * queuecommand() won't be invoked concurrently with reconnect() from outside
 550  * the SCSI EH. This is important since a reconnect() implementation may
 551  * reallocate resources needed by queuecommand().
 552  *
 553  * Notes:
 554  * - This function neither waits until outstanding requests have finished nor
 555  *   tries to abort these. It is the responsibility of the reconnect()
 556  *   function to finish outstanding commands before reconnecting to the target
 557  *   port.
 558  * - It is the responsibility of the caller to ensure that the resources
 559  *   reallocated by the reconnect() function won't be used while this function
 560  *   is in progress. One possible strategy is to invoke this function from
 561  *   the context of the SCSI EH thread only. Another possible strategy is to
 562  *   lock the rport mutex inside each SCSI LLD callback that can be invoked by
 563  *   the SCSI EH (the scsi_host_template.eh_*() functions and also the
 564  *   scsi_host_template.queuecommand() function).
 565  */
 566 int srp_reconnect_rport(struct srp_rport *rport)
 567 {
 568         struct Scsi_Host *shost = rport_to_shost(rport);
 569         struct srp_internal *i = to_srp_internal(shost->transportt);
 570         struct scsi_device *sdev;
 571         int res;
 572
 573         pr_debug("SCSI host %s\n", dev_name(&shost->shost_gendev));
 574
 575         res = mutex_lock_interruptible(&rport->mutex);
 576         if (res)
 577                 goto out;
 578         scsi_target_block(&shost->shost_gendev);
 579         srp_wait_for_queuecommand(shost);
 580         res = rport->state != SRP_RPORT_LOST ? i->f->reconnect(rport) : -ENODEV;
 581         pr_debug("%s (state %d): transport.reconnect() returned %d\n",
 582                  dev_name(&shost->shost_gendev), rport->state, res);
 583         if (res == 0) {
 584                 cancel_delayed_work(&rport->fast_io_fail_work);
 585                 cancel_delayed_work(&rport->dev_loss_work);
 586
 587                 rport->failed_reconnects = 0;
 588                 srp_rport_set_state(rport, SRP_RPORT_RUNNING);
 589                 scsi_target_unblock(&shost->shost_gendev, SDEV_RUNNING);
 590                 /*
 591                  * If the SCSI error handler has offlined one or more devices,
 592                  * invoking scsi_target_unblock() won't change the state of
 593                  * these devices into running so do that explicitly.
 594                  */
 595                 spin_lock_irq(shost->host_lock);
 596                 __shost_for_each_device(sdev, shost)
 597                         if (sdev->sdev_state == SDEV_OFFLINE)
 598                                 sdev->sdev_state = SDEV_RUNNING;
 599                 spin_unlock_irq(shost->host_lock);
 600         } else if (rport->state == SRP_RPORT_RUNNING) {
 601                 /*
 602                  * srp_reconnect_rport() has been invoked with fast_io_fail
 603                  * and dev_loss off. Mark the port as failed and start the TL
 604                  * failure timers if these had not yet been started.
 605                  */
 606                 __rport_fail_io_fast(rport);
 607                 scsi_target_unblock(&shost->shost_gendev,
 608                                     SDEV_TRANSPORT_OFFLINE);
 609                 __srp_start_tl_fail_timers(rport);
 610         } else if (rport->state != SRP_RPORT_BLOCKED) {
 611                 scsi_target_unblock(&shost->shost_gendev,
 612                                     SDEV_TRANSPORT_OFFLINE);
 613         }
 614         mutex_unlock(&rport->mutex);
 615
 616 out:
 617         return res;
 618 }
 619 EXPORT_SYMBOL(srp_reconnect_rport);
 620
 621 /**
 622  * srp_timed_out() - SRP transport intercept of the SCSI timeout EH
 623  * @scmd: SCSI command.
 624  *
 625  * If a timeout occurs while an rport is in the blocked state, ask the SCSI
 626  * EH to continue waiting (BLK_EH_RESET_TIMER). Otherwise let the SCSI core
 627  * handle the timeout (BLK_EH_NOT_HANDLED).
 628  *
 629  * Note: This function is called from soft-IRQ context and with the request
 630  * queue lock held.
 631  */
 632 static enum blk_eh_timer_return srp_timed_out(struct scsi_cmnd *scmd)
 633 {
 634         struct scsi_device *sdev = scmd->device;
 635         struct Scsi_Host *shost = sdev->host;
 636         struct srp_internal *i = to_srp_internal(shost->transportt);
 637         struct srp_rport *rport = shost_to_rport(shost);
 638
 639         pr_debug("timeout for sdev %s\n", dev_name(&sdev->sdev_gendev));
 640         return rport->fast_io_fail_tmo < 0 && rport->dev_loss_tmo < 0 &&
 641                 i->f->reset_timer_if_blocked && scsi_device_blocked(sdev) ?
 642                 BLK_EH_RESET_TIMER : BLK_EH_NOT_HANDLED;
 643 }
 644
 645 static void srp_rport_release(struct device *dev)
 646 {
 647         struct srp_rport *rport = dev_to_rport(dev);
 648
 649         put_device(dev->parent);
 650         kfree(rport);
 651 }
 652
 653 static int scsi_is_srp_rport(const struct device *dev)
 654 {
 655         return dev->release == srp_rport_release;
 656 }
 657
 658 static int srp_rport_match(struct attribute_container *cont,
 659                            struct device *dev)
 660 {
 661         struct Scsi_Host *shost;
 662         struct srp_internal *i;
 663
 664         if (!scsi_is_srp_rport(dev))
 665                 return 0;
 666
 667         shost = dev_to_shost(dev->parent);
 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->rport_attr_cont.ac == cont;
 675 }
 676
 677 static int srp_host_match(struct attribute_container *cont, struct device *dev)
 678 {
 679         struct Scsi_Host *shost;
 680         struct srp_internal *i;
 681
 682         if (!scsi_is_host_device(dev))
 683                 return 0;
 684
 685         shost = dev_to_shost(dev);
 686         if (!shost->transportt)
 687                 return 0;
 688         if (shost->transportt->host_attrs.ac.class != &srp_host_class.class)
 689                 return 0;
 690
 691         i = to_srp_internal(shost->transportt);
 692         return &i->t.host_attrs.ac == cont;
 693 }
 694
 695 /**
 696  * srp_rport_get() - increment rport reference count
 697  * @rport: SRP target port.
 698  */
 699 void srp_rport_get(struct srp_rport *rport)
 700 {
 701         get_device(&rport->dev);
 702 }
 703 EXPORT_SYMBOL(srp_rport_get);
 704
 705 /**
 706  * srp_rport_put() - decrement rport reference count
 707  * @rport: SRP target port.
 708  */
 709 void srp_rport_put(struct srp_rport *rport)
 710 {
 711         put_device(&rport->dev);
 712 }
 713 EXPORT_SYMBOL(srp_rport_put);
 714
 715 /**
 716  * srp_rport_add - add a SRP remote port to the device hierarchy
 717  * @shost:      scsi host the remote port is connected to.
 718  * @ids:        The port id for the remote port.
 719  *
 720  * Publishes a port to the rest of the system.
 721  */
 722 struct srp_rport *srp_rport_add(struct Scsi_Host *shost,
 723                                 struct srp_rport_identifiers *ids)
 724 {
 725         struct srp_rport *rport;
 726         struct device *parent = &shost->shost_gendev;
 727         struct srp_internal *i = to_srp_internal(shost->transportt);
 728         int id, ret;
 729
 730         rport = kzalloc(sizeof(*rport), GFP_KERNEL);
 731         if (!rport)
 732                 return ERR_PTR(-ENOMEM);
 733
 734         mutex_init(&rport->mutex);
 735
 736         device_initialize(&rport->dev);
 737
 738         rport->dev.parent = get_device(parent);
 739         rport->dev.release = srp_rport_release;
 740
 741         memcpy(rport->port_id, ids->port_id, sizeof(rport->port_id));
 742         rport->roles = ids->roles;
 743
 744         if (i->f->reconnect)
 745                 rport->reconnect_delay = i->f->reconnect_delay ?
 746                         *i->f->reconnect_delay : 10;
 747         INIT_DELAYED_WORK(&rport->reconnect_work, srp_reconnect_work);
 748         rport->fast_io_fail_tmo = i->f->fast_io_fail_tmo ?
 749                 *i->f->fast_io_fail_tmo : 15;
 750         rport->dev_loss_tmo = i->f->dev_loss_tmo ? *i->f->dev_loss_tmo : 60;
 751         INIT_DELAYED_WORK(&rport->fast_io_fail_work,
 752                           rport_fast_io_fail_timedout);
 753         INIT_DELAYED_WORK(&rport->dev_loss_work, rport_dev_loss_timedout);
 754
 755         id = atomic_inc_return(&to_srp_host_attrs(shost)->next_port_id);
 756         dev_set_name(&rport->dev, "port-%d:%d", shost->host_no, id);
 757
 758         transport_setup_device(&rport->dev);
 759
 760         ret = device_add(&rport->dev);
 761         if (ret) {
 762                 transport_destroy_device(&rport->dev);
 763                 put_device(&rport->dev);
 764                 return ERR_PTR(ret);
 765         }
 766
 767         transport_add_device(&rport->dev);
 768         transport_configure_device(&rport->dev);
 769
 770         return rport;
 771 }
 772 EXPORT_SYMBOL_GPL(srp_rport_add);
 773
 774 /**
 775  * srp_rport_del  -  remove a SRP remote port
 776  * @rport:      SRP remote port to remove
 777  *
 778  * Removes the specified SRP remote port.
 779  */
 780 void srp_rport_del(struct srp_rport *rport)
 781 {
 782         struct device *dev = &rport->dev;
 783
 784         transport_remove_device(dev);
 785         device_del(dev);
 786         transport_destroy_device(dev);
 787
 788         put_device(dev);
 789 }
 790 EXPORT_SYMBOL_GPL(srp_rport_del);
 791
 792 static int do_srp_rport_del(struct device *dev, void *data)
 793 {
 794         if (scsi_is_srp_rport(dev))
 795                 srp_rport_del(dev_to_rport(dev));
 796         return 0;
 797 }
 798
 799 /**
 800  * srp_remove_host  -  tear down a Scsi_Host's SRP data structures
 801  * @shost:      Scsi Host that is torn down
 802  *
 803  * Removes all SRP remote ports for a given Scsi_Host.
 804  * Must be called just before scsi_remove_host for SRP HBAs.
 805  */
 806 void srp_remove_host(struct Scsi_Host *shost)
 807 {
 808         device_for_each_child(&shost->shost_gendev, NULL, do_srp_rport_del);
 809 }
 810 EXPORT_SYMBOL_GPL(srp_remove_host);
 811
 812 /**
 813  * srp_stop_rport_timers - stop the transport layer recovery timers
 814  * @rport: SRP remote port for which to stop the timers.
 815  *
 816  * Must be called after srp_remove_host() and scsi_remove_host(). The caller
 817  * must hold a reference on the rport (rport->dev) and on the SCSI host
 818  * (rport->dev.parent).
 819  */
 820 void srp_stop_rport_timers(struct srp_rport *rport)
 821 {
 822         mutex_lock(&rport->mutex);
 823         if (rport->state == SRP_RPORT_BLOCKED)
 824                 __rport_fail_io_fast(rport);
 825         srp_rport_set_state(rport, SRP_RPORT_LOST);
 826         mutex_unlock(&rport->mutex);
 827
 828         cancel_delayed_work_sync(&rport->reconnect_work);
 829         cancel_delayed_work_sync(&rport->fast_io_fail_work);
 830         cancel_delayed_work_sync(&rport->dev_loss_work);
 831 }
 832 EXPORT_SYMBOL_GPL(srp_stop_rport_timers);
 833
 834 static int srp_tsk_mgmt_response(struct Scsi_Host *shost, u64 nexus, u64 tm_id,
 835                                  int result)
 836 {
 837         struct srp_internal *i = to_srp_internal(shost->transportt);
 838         return i->f->tsk_mgmt_response(shost, nexus, tm_id, result);
 839 }
 840
 841 static int srp_it_nexus_response(struct Scsi_Host *shost, u64 nexus, int result)
 842 {
 843         struct srp_internal *i = to_srp_internal(shost->transportt);
 844         return i->f->it_nexus_response(shost, nexus, result);
 845 }
 846
 847 /**
 848  * srp_attach_transport  -  instantiate SRP transport template
 849  * @ft:         SRP transport class function template
 850  */
 851 struct scsi_transport_template *
 852 srp_attach_transport(struct srp_function_template *ft)
 853 {
 854         int count;
 855         struct srp_internal *i;
 856
 857         i = kzalloc(sizeof(*i), GFP_KERNEL);
 858         if (!i)
 859                 return NULL;
 860
 861         i->t.eh_timed_out = srp_timed_out;
 862
 863         i->t.tsk_mgmt_response = srp_tsk_mgmt_response;
 864         i->t.it_nexus_response = srp_it_nexus_response;
 865
 866         i->t.host_size = sizeof(struct srp_host_attrs);
 867         i->t.host_attrs.ac.attrs = &i->host_attrs[0];
 868         i->t.host_attrs.ac.class = &srp_host_class.class;
 869         i->t.host_attrs.ac.match = srp_host_match;
 870         i->host_attrs[0] = NULL;
 871         transport_container_register(&i->t.host_attrs);
 872
 873         i->rport_attr_cont.ac.attrs = &i->rport_attrs[0];
 874         i->rport_attr_cont.ac.class = &srp_rport_class.class;
 875         i->rport_attr_cont.ac.match = srp_rport_match;
 876
 877         count = 0;
 878         i->rport_attrs[count++] = &dev_attr_port_id;
 879         i->rport_attrs[count++] = &dev_attr_roles;
 880         if (ft->has_rport_state) {
 881                 i->rport_attrs[count++] = &dev_attr_state;
 882                 i->rport_attrs[count++] = &dev_attr_fast_io_fail_tmo;
 883                 i->rport_attrs[count++] = &dev_attr_dev_loss_tmo;
 884         }
 885         if (ft->reconnect) {
 886                 i->rport_attrs[count++] = &dev_attr_reconnect_delay;
 887                 i->rport_attrs[count++] = &dev_attr_failed_reconnects;
 888         }
 889         if (ft->rport_delete)
 890                 i->rport_attrs[count++] = &dev_attr_delete;
 891         i->rport_attrs[count++] = NULL;
 892         BUG_ON(count > ARRAY_SIZE(i->rport_attrs));
 893
 894         transport_container_register(&i->rport_attr_cont);
 895
 896         i->f = ft;
 897
 898         return &i->t;
 899 }
 900 EXPORT_SYMBOL_GPL(srp_attach_transport);
 901
 902 /**
 903  * srp_release_transport  -  release SRP transport template instance
 904  * @t:          transport template instance
 905  */
 906 void srp_release_transport(struct scsi_transport_template *t)
 907 {
 908         struct srp_internal *i = to_srp_internal(t);
 909
 910         transport_container_unregister(&i->t.host_attrs);
 911         transport_container_unregister(&i->rport_attr_cont);
 912
 913         kfree(i);
 914 }
 915 EXPORT_SYMBOL_GPL(srp_release_transport);
 916
 917 static __init int srp_transport_init(void)
 918 {
 919         int ret;
 920
 921         ret = transport_class_register(&srp_host_class);
 922         if (ret)
 923                 return ret;
 924         ret = transport_class_register(&srp_rport_class);
 925         if (ret)
 926                 goto unregister_host_class;
 927
 928         return 0;
 929 unregister_host_class:
 930         transport_class_unregister(&srp_host_class);
 931         return ret;
 932 }
 933
 934 static void __exit srp_transport_exit(void)
 935 {
 936         transport_class_unregister(&srp_host_class);
 937         transport_class_unregister(&srp_rport_class);
 938 }
 939
 940 MODULE_AUTHOR("FUJITA Tomonori");
 941 MODULE_DESCRIPTION("SRP Transport Attributes");
 942 MODULE_LICENSE("GPL");
 943
 944 module_init(srp_transport_init);
 945 module_exit(srp_transport_exit);