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 static 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
 218 static ssize_t show_reconnect_delay(struct device *dev,
 219                                     struct device_attribute *attr, char *buf)
 220 {
 221         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 222
 223         return srp_show_tmo(buf, rport->reconnect_delay);
 224 }
 225
 226 static ssize_t store_reconnect_delay(struct device *dev,
 227                                      struct device_attribute *attr,
 228                                      const char *buf, const size_t count)
 229 {
 230         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 231         int res, delay;
 232
 233         res = srp_parse_tmo(&delay, buf);
 234         if (res)
 235                 goto out;
 236         res = srp_tmo_valid(delay, rport->fast_io_fail_tmo,
 237                             rport->dev_loss_tmo);
 238         if (res)
 239                 goto out;
 240
 241         if (rport->reconnect_delay <= 0 && delay > 0 &&
 242             rport->state != SRP_RPORT_RUNNING) {
 243                 queue_delayed_work(system_long_wq, &rport->reconnect_work,
 244                                    delay * HZ);
 245         } else if (delay <= 0) {
 246                 cancel_delayed_work(&rport->reconnect_work);
 247         }
 248         rport->reconnect_delay = delay;
 249         res = count;
 250
 251 out:
 252         return res;
 253 }
 254
 255 static DEVICE_ATTR(reconnect_delay, S_IRUGO | S_IWUSR, show_reconnect_delay,
 256                    store_reconnect_delay);
 257
 258 static ssize_t show_failed_reconnects(struct device *dev,
 259                                       struct device_attribute *attr, char *buf)
 260 {
 261         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 262
 263         return sprintf(buf, "%d\n", rport->failed_reconnects);
 264 }
 265
 266 static DEVICE_ATTR(failed_reconnects, S_IRUGO, show_failed_reconnects, NULL);
 267
 268 static ssize_t show_srp_rport_fast_io_fail_tmo(struct device *dev,
 269                                                struct device_attribute *attr,
 270                                                char *buf)
 271 {
 272         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 273
 274         return srp_show_tmo(buf, rport->fast_io_fail_tmo);
 275 }
 276
 277 static ssize_t store_srp_rport_fast_io_fail_tmo(struct device *dev,
 278                                                 struct device_attribute *attr,
 279                                                 const char *buf, size_t count)
 280 {
 281         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 282         int res;
 283         int fast_io_fail_tmo;
 284
 285         res = srp_parse_tmo(&fast_io_fail_tmo, buf);
 286         if (res)
 287                 goto out;
 288         res = srp_tmo_valid(rport->reconnect_delay, fast_io_fail_tmo,
 289                             rport->dev_loss_tmo);
 290         if (res)
 291                 goto out;
 292         rport->fast_io_fail_tmo = fast_io_fail_tmo;
 293         res = count;
 294
 295 out:
 296         return res;
 297 }
 298
 299 static DEVICE_ATTR(fast_io_fail_tmo, S_IRUGO | S_IWUSR,
 300                    show_srp_rport_fast_io_fail_tmo,
 301                    store_srp_rport_fast_io_fail_tmo);
 302
 303 static ssize_t show_srp_rport_dev_loss_tmo(struct device *dev,
 304                                            struct device_attribute *attr,
 305                                            char *buf)
 306 {
 307         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 308
 309         return srp_show_tmo(buf, rport->dev_loss_tmo);
 310 }
 311
 312 static ssize_t store_srp_rport_dev_loss_tmo(struct device *dev,
 313                                             struct device_attribute *attr,
 314                                             const char *buf, size_t count)
 315 {
 316         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 317         int res;
 318         int dev_loss_tmo;
 319
 320         res = srp_parse_tmo(&dev_loss_tmo, buf);
 321         if (res)
 322                 goto out;
 323         res = srp_tmo_valid(rport->reconnect_delay, rport->fast_io_fail_tmo,
 324                             dev_loss_tmo);
 325         if (res)
 326                 goto out;
 327         rport->dev_loss_tmo = dev_loss_tmo;
 328         res = count;
 329
 330 out:
 331         return res;
 332 }
 333
 334 static DEVICE_ATTR(dev_loss_tmo, S_IRUGO | S_IWUSR,
 335                    show_srp_rport_dev_loss_tmo,
 336                    store_srp_rport_dev_loss_tmo);
 337
 338 static int srp_rport_set_state(struct srp_rport *rport,
 339                                enum srp_rport_state new_state)
 340 {
 341         enum srp_rport_state old_state = rport->state;
 342
 343         lockdep_assert_held(&rport->mutex);
 344
 345         switch (new_state) {
 346         case SRP_RPORT_RUNNING:
 347                 switch (old_state) {
 348                 case SRP_RPORT_LOST:
 349                         goto invalid;
 350                 default:
 351                         break;
 352                 }
 353                 break;
 354         case SRP_RPORT_BLOCKED:
 355                 switch (old_state) {
 356                 case SRP_RPORT_RUNNING:
 357                         break;
 358                 default:
 359                         goto invalid;
 360                 }
 361                 break;
 362         case SRP_RPORT_FAIL_FAST:
 363                 switch (old_state) {
 364                 case SRP_RPORT_LOST:
 365                         goto invalid;
 366                 default:
 367                         break;
 368                 }
 369                 break;
 370         case SRP_RPORT_LOST:
 371                 break;
 372         }
 373         rport->state = new_state;
 374         return 0;
 375
 376 invalid:
 377         return -EINVAL;
 378 }
 379
 380 /**
 381  * srp_reconnect_work() - reconnect and schedule a new attempt if necessary
 382  * @work: Work structure used for scheduling this operation.
 383  */
 384 static void srp_reconnect_work(struct work_struct *work)
 385 {
 386         struct srp_rport *rport = container_of(to_delayed_work(work),
 387                                         struct srp_rport, reconnect_work);
 388         struct Scsi_Host *shost = rport_to_shost(rport);
 389         int delay, res;
 390
 391         res = srp_reconnect_rport(rport);
 392         if (res != 0) {
 393                 shost_printk(KERN_ERR, shost,
 394                              "reconnect attempt %d failed (%d)\n",
 395                              ++rport->failed_reconnects, res);
 396                 delay = rport->reconnect_delay *
 397                         min(100, max(1, rport->failed_reconnects - 10));
 398                 if (delay > 0)
 399                         queue_delayed_work(system_long_wq,
 400                                            &rport->reconnect_work, delay * HZ);
 401         }
 402 }
 403
 404 /**
 405  * scsi_request_fn_active() - number of kernel threads inside scsi_request_fn()
 406  * @shost: SCSI host for which to count the number of scsi_request_fn() callers.
 407  *
 408  * To do: add support for scsi-mq in this function.
 409  */
 410 static int scsi_request_fn_active(struct Scsi_Host *shost)
 411 {
 412         struct scsi_device *sdev;
 413         struct request_queue *q;
 414         int request_fn_active = 0;
 415
 416         shost_for_each_device(sdev, shost) {
 417                 q = sdev->request_queue;
 418
 419                 spin_lock_irq(q->queue_lock);
 420                 request_fn_active += q->request_fn_active;
 421                 spin_unlock_irq(q->queue_lock);
 422         }
 423
 424         return request_fn_active;
 425 }
 426
 427 /* Wait until ongoing shost->hostt->queuecommand() calls have finished. */
 428 static void srp_wait_for_queuecommand(struct Scsi_Host *shost)
 429 {
 430         while (scsi_request_fn_active(shost))
 431                 msleep(20);
 432 }
 433
 434 static void __rport_fail_io_fast(struct srp_rport *rport)
 435 {
 436         struct Scsi_Host *shost = rport_to_shost(rport);
 437         struct srp_internal *i;
 438
 439         lockdep_assert_held(&rport->mutex);
 440
 441         if (srp_rport_set_state(rport, SRP_RPORT_FAIL_FAST))
 442                 return;
 443         scsi_target_unblock(rport->dev.parent, SDEV_TRANSPORT_OFFLINE);
 444
 445         /* Involve the LLD if possible to terminate all I/O on the rport. */
 446         i = to_srp_internal(shost->transportt);
 447         if (i->f->terminate_rport_io) {
 448                 srp_wait_for_queuecommand(shost);
 449                 i->f->terminate_rport_io(rport);
 450         }
 451 }
 452
 453 /**
 454  * rport_fast_io_fail_timedout() - fast I/O failure timeout handler
 455  * @work: Work structure used for scheduling this operation.
 456  */
 457 static void rport_fast_io_fail_timedout(struct work_struct *work)
 458 {
 459         struct srp_rport *rport = container_of(to_delayed_work(work),
 460                                         struct srp_rport, fast_io_fail_work);
 461         struct Scsi_Host *shost = rport_to_shost(rport);
 462
 463         pr_info("fast_io_fail_tmo expired for SRP %s / %s.\n",
 464                 dev_name(&rport->dev), dev_name(&shost->shost_gendev));
 465
 466         mutex_lock(&rport->mutex);
 467         if (rport->state == SRP_RPORT_BLOCKED)
 468                 __rport_fail_io_fast(rport);
 469         mutex_unlock(&rport->mutex);
 470 }
 471
 472 /**
 473  * rport_dev_loss_timedout() - device loss timeout handler
 474  * @work: Work structure used for scheduling this operation.
 475  */
 476 static void rport_dev_loss_timedout(struct work_struct *work)
 477 {
 478         struct srp_rport *rport = container_of(to_delayed_work(work),
 479                                         struct srp_rport, dev_loss_work);
 480         struct Scsi_Host *shost = rport_to_shost(rport);
 481         struct srp_internal *i = to_srp_internal(shost->transportt);
 482
 483         pr_info("dev_loss_tmo expired for SRP %s / %s.\n",
 484                 dev_name(&rport->dev), dev_name(&shost->shost_gendev));
 485
 486         mutex_lock(&rport->mutex);
 487         WARN_ON(srp_rport_set_state(rport, SRP_RPORT_LOST) != 0);
 488         scsi_target_unblock(rport->dev.parent, SDEV_TRANSPORT_OFFLINE);
 489         mutex_unlock(&rport->mutex);
 490
 491         i->f->rport_delete(rport);
 492 }
 493
 494 static void __srp_start_tl_fail_timers(struct srp_rport *rport)
 495 {
 496         struct Scsi_Host *shost = rport_to_shost(rport);
 497         int delay, fast_io_fail_tmo, dev_loss_tmo;
 498
 499         lockdep_assert_held(&rport->mutex);
 500
 501         delay = rport->reconnect_delay;
 502         fast_io_fail_tmo = rport->fast_io_fail_tmo;
 503         dev_loss_tmo = rport->dev_loss_tmo;
 504         pr_debug("%s current state: %d\n", dev_name(&shost->shost_gendev),
 505                  rport->state);
 506
 507         if (rport->state == SRP_RPORT_LOST)
 508                 return;
 509         if (delay > 0)
 510                 queue_delayed_work(system_long_wq, &rport->reconnect_work,
 511                                    1UL * delay * HZ);
 512         if ((fast_io_fail_tmo >= 0 || dev_loss_tmo >= 0) &&
 513             srp_rport_set_state(rport, SRP_RPORT_BLOCKED) == 0) {
 514                 pr_debug("%s new state: %d\n", dev_name(&shost->shost_gendev),
 515                          rport->state);
 516                 scsi_target_block(&shost->shost_gendev);
 517                 if (fast_io_fail_tmo >= 0)
 518                         queue_delayed_work(system_long_wq,
 519                                            &rport->fast_io_fail_work,
 520                                            1UL * fast_io_fail_tmo * HZ);
 521                 if (dev_loss_tmo >= 0)
 522                         queue_delayed_work(system_long_wq,
 523                                            &rport->dev_loss_work,
 524                                            1UL * dev_loss_tmo * HZ);
 525         }
 526 }
 527
 528 /**
 529  * srp_start_tl_fail_timers() - start the transport layer failure timers
 530  * @rport: SRP target port.
 531  *
 532  * Start the transport layer fast I/O failure and device loss timers. Do not
 533  * modify a timer that was already started.
 534  */
 535 void srp_start_tl_fail_timers(struct srp_rport *rport)
 536 {
 537         mutex_lock(&rport->mutex);
 538         __srp_start_tl_fail_timers(rport);
 539         mutex_unlock(&rport->mutex);
 540 }
 541 EXPORT_SYMBOL(srp_start_tl_fail_timers);
 542
 543 /**
 544  * srp_reconnect_rport() - reconnect to an SRP target port
 545  * @rport: SRP target port.
 546  *
 547  * Blocks SCSI command queueing before invoking reconnect() such that
 548  * queuecommand() won't be invoked concurrently with reconnect() from outside
 549  * the SCSI EH. This is important since a reconnect() implementation may
 550  * reallocate resources needed by queuecommand().
 551  *
 552  * Notes:
 553  * - This function neither waits until outstanding requests have finished nor
 554  *   tries to abort these. It is the responsibility of the reconnect()
 555  *   function to finish outstanding commands before reconnecting to the target
 556  *   port.
 557  * - It is the responsibility of the caller to ensure that the resources
 558  *   reallocated by the reconnect() function won't be used while this function
 559  *   is in progress. One possible strategy is to invoke this function from
 560  *   the context of the SCSI EH thread only. Another possible strategy is to
 561  *   lock the rport mutex inside each SCSI LLD callback that can be invoked by
 562  *   the SCSI EH (the scsi_host_template.eh_*() functions and also the
 563  *   scsi_host_template.queuecommand() function).
 564  */
 565 int srp_reconnect_rport(struct srp_rport *rport)
 566 {
 567         struct Scsi_Host *shost = rport_to_shost(rport);
 568         struct srp_internal *i = to_srp_internal(shost->transportt);
 569         struct scsi_device *sdev;
 570         int res;
 571
 572         pr_debug("SCSI host %s\n", dev_name(&shost->shost_gendev));
 573
 574         res = mutex_lock_interruptible(&rport->mutex);
 575         if (res)
 576                 goto out;
 577         scsi_target_block(&shost->shost_gendev);
 578         srp_wait_for_queuecommand(shost);
 579         res = rport->state != SRP_RPORT_LOST ? i->f->reconnect(rport) : -ENODEV;
 580         pr_debug("%s (state %d): transport.reconnect() returned %d\n",
 581                  dev_name(&shost->shost_gendev), rport->state, res);
 582         if (res == 0) {
 583                 cancel_delayed_work(&rport->fast_io_fail_work);
 584                 cancel_delayed_work(&rport->dev_loss_work);
 585
 586                 rport->failed_reconnects = 0;
 587                 srp_rport_set_state(rport, SRP_RPORT_RUNNING);
 588                 scsi_target_unblock(&shost->shost_gendev, SDEV_RUNNING);
 589                 /*
 590                  * If the SCSI error handler has offlined one or more devices,
 591                  * invoking scsi_target_unblock() won't change the state of
 592                  * these devices into running so do that explicitly.
 593                  */
 594                 spin_lock_irq(shost->host_lock);
 595                 __shost_for_each_device(sdev, shost)
 596                         if (sdev->sdev_state == SDEV_OFFLINE)
 597                                 sdev->sdev_state = SDEV_RUNNING;
 598                 spin_unlock_irq(shost->host_lock);
 599         } else if (rport->state == SRP_RPORT_RUNNING) {
 600                 /*
 601                  * srp_reconnect_rport() has been invoked with fast_io_fail
 602                  * and dev_loss off. Mark the port as failed and start the TL
 603                  * failure timers if these had not yet been started.
 604                  */
 605                 __rport_fail_io_fast(rport);
 606                 scsi_target_unblock(&shost->shost_gendev,
 607                                     SDEV_TRANSPORT_OFFLINE);
 608                 __srp_start_tl_fail_timers(rport);
 609         } else if (rport->state != SRP_RPORT_BLOCKED) {
 610                 scsi_target_unblock(&shost->shost_gendev,
 611                                     SDEV_TRANSPORT_OFFLINE);
 612         }
 613         mutex_unlock(&rport->mutex);
 614
 615 out:
 616         return res;
 617 }
 618 EXPORT_SYMBOL(srp_reconnect_rport);
 619
 620 /**
 621  * srp_timed_out() - SRP transport intercept of the SCSI timeout EH
 622  * @scmd: SCSI command.
 623  *
 624  * If a timeout occurs while an rport is in the blocked state, ask the SCSI
 625  * EH to continue waiting (BLK_EH_RESET_TIMER). Otherwise let the SCSI core
 626  * handle the timeout (BLK_EH_NOT_HANDLED).
 627  *
 628  * Note: This function is called from soft-IRQ context and with the request
 629  * queue lock held.
 630  */
 631 static enum blk_eh_timer_return srp_timed_out(struct scsi_cmnd *scmd)
 632 {
 633         struct scsi_device *sdev = scmd->device;
 634         struct Scsi_Host *shost = sdev->host;
 635         struct srp_internal *i = to_srp_internal(shost->transportt);
 636         struct srp_rport *rport = shost_to_rport(shost);
 637
 638         pr_debug("timeout for sdev %s\n", dev_name(&sdev->sdev_gendev));
 639         return rport->fast_io_fail_tmo < 0 && rport->dev_loss_tmo < 0 &&
 640                 i->f->reset_timer_if_blocked && scsi_device_blocked(sdev) ?
 641                 BLK_EH_RESET_TIMER : BLK_EH_NOT_HANDLED;
 642 }
 643
 644 static void srp_rport_release(struct device *dev)
 645 {
 646         struct srp_rport *rport = dev_to_rport(dev);
 647
 648         put_device(dev->parent);
 649         kfree(rport);
 650 }
 651
 652 static int scsi_is_srp_rport(const struct device *dev)
 653 {
 654         return dev->release == srp_rport_release;
 655 }
 656
 657 static int srp_rport_match(struct attribute_container *cont,
 658                            struct device *dev)
 659 {
 660         struct Scsi_Host *shost;
 661         struct srp_internal *i;
 662
 663         if (!scsi_is_srp_rport(dev))
 664                 return 0;
 665
 666         shost = dev_to_shost(dev->parent);
 667         if (!shost->transportt)
 668                 return 0;
 669         if (shost->transportt->host_attrs.ac.class != &srp_host_class.class)
 670                 return 0;
 671
 672         i = to_srp_internal(shost->transportt);
 673         return &i->rport_attr_cont.ac == cont;
 674 }
 675
 676 static int srp_host_match(struct attribute_container *cont, struct device *dev)
 677 {
 678         struct Scsi_Host *shost;
 679         struct srp_internal *i;
 680
 681         if (!scsi_is_host_device(dev))
 682                 return 0;
 683
 684         shost = dev_to_shost(dev);
 685         if (!shost->transportt)
 686                 return 0;
 687         if (shost->transportt->host_attrs.ac.class != &srp_host_class.class)
 688                 return 0;
 689
 690         i = to_srp_internal(shost->transportt);
 691         return &i->t.host_attrs.ac == cont;
 692 }
 693
 694 /**
 695  * srp_rport_get() - increment rport reference count
 696  * @rport: SRP target port.
 697  */
 698 void srp_rport_get(struct srp_rport *rport)
 699 {
 700         get_device(&rport->dev);
 701 }
 702 EXPORT_SYMBOL(srp_rport_get);
 703
 704 /**
 705  * srp_rport_put() - decrement rport reference count
 706  * @rport: SRP target port.
 707  */
 708 void srp_rport_put(struct srp_rport *rport)
 709 {
 710         put_device(&rport->dev);
 711 }
 712 EXPORT_SYMBOL(srp_rport_put);
 713
 714 /**
 715  * srp_rport_add - add a SRP remote port to the device hierarchy
 716  * @shost:      scsi host the remote port is connected to.
 717  * @ids:        The port id for the remote port.
 718  *
 719  * Publishes a port to the rest of the system.
 720  */
 721 struct srp_rport *srp_rport_add(struct Scsi_Host *shost,
 722                                 struct srp_rport_identifiers *ids)
 723 {
 724         struct srp_rport *rport;
 725         struct device *parent = &shost->shost_gendev;
 726         struct srp_internal *i = to_srp_internal(shost->transportt);
 727         int id, ret;
 728
 729         rport = kzalloc(sizeof(*rport), GFP_KERNEL);
 730         if (!rport)
 731                 return ERR_PTR(-ENOMEM);
 732
 733         mutex_init(&rport->mutex);
 734
 735         device_initialize(&rport->dev);
 736
 737         rport->dev.parent = get_device(parent);
 738         rport->dev.release = srp_rport_release;
 739
 740         memcpy(rport->port_id, ids->port_id, sizeof(rport->port_id));
 741         rport->roles = ids->roles;
 742
 743         if (i->f->reconnect)
 744                 rport->reconnect_delay = i->f->reconnect_delay ?
 745                         *i->f->reconnect_delay : 10;
 746         INIT_DELAYED_WORK(&rport->reconnect_work, srp_reconnect_work);
 747         rport->fast_io_fail_tmo = i->f->fast_io_fail_tmo ?
 748                 *i->f->fast_io_fail_tmo : 15;
 749         rport->dev_loss_tmo = i->f->dev_loss_tmo ? *i->f->dev_loss_tmo : 60;
 750         INIT_DELAYED_WORK(&rport->fast_io_fail_work,
 751                           rport_fast_io_fail_timedout);
 752         INIT_DELAYED_WORK(&rport->dev_loss_work, rport_dev_loss_timedout);
 753
 754         id = atomic_inc_return(&to_srp_host_attrs(shost)->next_port_id);
 755         dev_set_name(&rport->dev, "port-%d:%d", shost->host_no, id);
 756
 757         transport_setup_device(&rport->dev);
 758
 759         ret = device_add(&rport->dev);
 760         if (ret) {
 761                 transport_destroy_device(&rport->dev);
 762                 put_device(&rport->dev);
 763                 return ERR_PTR(ret);
 764         }
 765
 766         transport_add_device(&rport->dev);
 767         transport_configure_device(&rport->dev);
 768
 769         return rport;
 770 }
 771 EXPORT_SYMBOL_GPL(srp_rport_add);
 772
 773 /**
 774  * srp_rport_del  -  remove a SRP remote port
 775  * @rport:      SRP remote port to remove
 776  *
 777  * Removes the specified SRP remote port.
 778  */
 779 void srp_rport_del(struct srp_rport *rport)
 780 {
 781         struct device *dev = &rport->dev;
 782
 783         transport_remove_device(dev);
 784         device_del(dev);
 785         transport_destroy_device(dev);
 786
 787         put_device(dev);
 788 }
 789 EXPORT_SYMBOL_GPL(srp_rport_del);
 790
 791 static int do_srp_rport_del(struct device *dev, void *data)
 792 {
 793         if (scsi_is_srp_rport(dev))
 794                 srp_rport_del(dev_to_rport(dev));
 795         return 0;
 796 }
 797
 798 /**
 799  * srp_remove_host  -  tear down a Scsi_Host's SRP data structures
 800  * @shost:      Scsi Host that is torn down
 801  *
 802  * Removes all SRP remote ports for a given Scsi_Host.
 803  * Must be called just before scsi_remove_host for SRP HBAs.
 804  */
 805 void srp_remove_host(struct Scsi_Host *shost)
 806 {
 807         device_for_each_child(&shost->shost_gendev, NULL, do_srp_rport_del);
 808 }
 809 EXPORT_SYMBOL_GPL(srp_remove_host);
 810
 811 /**
 812  * srp_stop_rport_timers - stop the transport layer recovery timers
 813  * @rport: SRP remote port for which to stop the timers.
 814  *
 815  * Must be called after srp_remove_host() and scsi_remove_host(). The caller
 816  * must hold a reference on the rport (rport->dev) and on the SCSI host
 817  * (rport->dev.parent).
 818  */
 819 void srp_stop_rport_timers(struct srp_rport *rport)
 820 {
 821         mutex_lock(&rport->mutex);
 822         if (rport->state == SRP_RPORT_BLOCKED)
 823                 __rport_fail_io_fast(rport);
 824         srp_rport_set_state(rport, SRP_RPORT_LOST);
 825         mutex_unlock(&rport->mutex);
 826
 827         cancel_delayed_work_sync(&rport->reconnect_work);
 828         cancel_delayed_work_sync(&rport->fast_io_fail_work);
 829         cancel_delayed_work_sync(&rport->dev_loss_work);
 830 }
 831 EXPORT_SYMBOL_GPL(srp_stop_rport_timers);
 832
 833 static int srp_tsk_mgmt_response(struct Scsi_Host *shost, u64 nexus, u64 tm_id,
 834                                  int result)
 835 {
 836         struct srp_internal *i = to_srp_internal(shost->transportt);
 837         return i->f->tsk_mgmt_response(shost, nexus, tm_id, result);
 838 }
 839
 840 static int srp_it_nexus_response(struct Scsi_Host *shost, u64 nexus, int result)
 841 {
 842         struct srp_internal *i = to_srp_internal(shost->transportt);
 843         return i->f->it_nexus_response(shost, nexus, result);
 844 }
 845
 846 /**
 847  * srp_attach_transport  -  instantiate SRP transport template
 848  * @ft:         SRP transport class function template
 849  */
 850 struct scsi_transport_template *
 851 srp_attach_transport(struct srp_function_template *ft)
 852 {
 853         int count;
 854         struct srp_internal *i;
 855
 856         i = kzalloc(sizeof(*i), GFP_KERNEL);
 857         if (!i)
 858                 return NULL;
 859
 860         i->t.eh_timed_out = srp_timed_out;
 861
 862         i->t.tsk_mgmt_response = srp_tsk_mgmt_response;
 863         i->t.it_nexus_response = srp_it_nexus_response;
 864
 865         i->t.host_size = sizeof(struct srp_host_attrs);
 866         i->t.host_attrs.ac.attrs = &i->host_attrs[0];
 867         i->t.host_attrs.ac.class = &srp_host_class.class;
 868         i->t.host_attrs.ac.match = srp_host_match;
 869         i->host_attrs[0] = NULL;
 870         transport_container_register(&i->t.host_attrs);
 871
 872         i->rport_attr_cont.ac.attrs = &i->rport_attrs[0];
 873         i->rport_attr_cont.ac.class = &srp_rport_class.class;
 874         i->rport_attr_cont.ac.match = srp_rport_match;
 875
 876         count = 0;
 877         i->rport_attrs[count++] = &dev_attr_port_id;
 878         i->rport_attrs[count++] = &dev_attr_roles;
 879         if (ft->has_rport_state) {
 880                 i->rport_attrs[count++] = &dev_attr_state;
 881                 i->rport_attrs[count++] = &dev_attr_fast_io_fail_tmo;
 882                 i->rport_attrs[count++] = &dev_attr_dev_loss_tmo;
 883         }
 884         if (ft->reconnect) {
 885                 i->rport_attrs[count++] = &dev_attr_reconnect_delay;
 886                 i->rport_attrs[count++] = &dev_attr_failed_reconnects;
 887         }
 888         if (ft->rport_delete)
 889                 i->rport_attrs[count++] = &dev_attr_delete;
 890         i->rport_attrs[count++] = NULL;
 891         BUG_ON(count > ARRAY_SIZE(i->rport_attrs));
 892
 893         transport_container_register(&i->rport_attr_cont);
 894
 895         i->f = ft;
 896
 897         return &i->t;
 898 }
 899 EXPORT_SYMBOL_GPL(srp_attach_transport);
 900
 901 /**
 902  * srp_release_transport  -  release SRP transport template instance
 903  * @t:          transport template instance
 904  */
 905 void srp_release_transport(struct scsi_transport_template *t)
 906 {
 907         struct srp_internal *i = to_srp_internal(t);
 908
 909         transport_container_unregister(&i->t.host_attrs);
 910         transport_container_unregister(&i->rport_attr_cont);
 911
 912         kfree(i);
 913 }
 914 EXPORT_SYMBOL_GPL(srp_release_transport);
 915
 916 static __init int srp_transport_init(void)
 917 {
 918         int ret;
 919
 920         ret = transport_class_register(&srp_host_class);
 921         if (ret)
 922                 return ret;
 923         ret = transport_class_register(&srp_rport_class);
 924         if (ret)
 925                 goto unregister_host_class;
 926
 927         return 0;
 928 unregister_host_class:
 929         transport_class_unregister(&srp_host_class);
 930         return ret;
 931 }
 932
 933 static void __exit srp_transport_exit(void)
 934 {
 935         transport_class_unregister(&srp_host_class);
 936         transport_class_unregister(&srp_rport_class);
 937 }
 938
 939 MODULE_AUTHOR("FUJITA Tomonori");
 940 MODULE_DESCRIPTION("SRP Transport Attributes");
 941 MODULE_LICENSE("GPL");
 942
 943 module_init(srp_transport_init);
 944 module_exit(srp_transport_exit);