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 #include "scsi_transport_srp_internal.h"
  37
  38 struct srp_host_attrs {
  39         atomic_t next_port_id;
  40 };
  41 #define to_srp_host_attrs(host) ((struct srp_host_attrs *)(host)->shost_data)
  42
  43 #define SRP_HOST_ATTRS 0
  44 #define SRP_RPORT_ATTRS 8
  45
  46 struct srp_internal {
  47         struct scsi_transport_template t;
  48         struct srp_function_template *f;
  49
  50         struct device_attribute *host_attrs[SRP_HOST_ATTRS + 1];
  51
  52         struct device_attribute *rport_attrs[SRP_RPORT_ATTRS + 1];
  53         struct transport_container rport_attr_cont;
  54 };
  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 /**
  66  * srp_tmo_valid() - check timeout combination validity
  67  *
  68  * The combination of the timeout parameters must be such that SCSI commands
  69  * are finished in a reasonable time. Hence do not allow the fast I/O fail
  70  * timeout to exceed SCSI_DEVICE_BLOCK_MAX_TIMEOUT. Furthermore, these
  71  * parameters must be such that multipath can detect failed paths timely.
  72  * Hence do not allow all three parameters to be disabled simultaneously.
  73  */
  74 int srp_tmo_valid(int reconnect_delay, int fast_io_fail_tmo, int dev_loss_tmo)
  75 {
  76         if (reconnect_delay < 0 && fast_io_fail_tmo < 0 && dev_loss_tmo < 0)
  77                 return -EINVAL;
  78         if (reconnect_delay == 0)
  79                 return -EINVAL;
  80         if (fast_io_fail_tmo > SCSI_DEVICE_BLOCK_MAX_TIMEOUT)
  81                 return -EINVAL;
  82         if (dev_loss_tmo >= LONG_MAX / HZ)
  83                 return -EINVAL;
  84         if (fast_io_fail_tmo >= 0 && dev_loss_tmo >= 0 &&
  85             fast_io_fail_tmo >= dev_loss_tmo)
  86                 return -EINVAL;
  87         return 0;
  88 }
  89 EXPORT_SYMBOL_GPL(srp_tmo_valid);
  90
  91 static int srp_host_setup(struct transport_container *tc, struct device *dev,
  92                           struct device *cdev)
  93 {
  94         struct Scsi_Host *shost = dev_to_shost(dev);
  95         struct srp_host_attrs *srp_host = to_srp_host_attrs(shost);
  96
  97         atomic_set(&srp_host->next_port_id, 0);
  98         return 0;
  99 }
 100
 101 static DECLARE_TRANSPORT_CLASS(srp_host_class, "srp_host", srp_host_setup,
 102                                NULL, NULL);
 103
 104 static DECLARE_TRANSPORT_CLASS(srp_rport_class, "srp_remote_ports",
 105                                NULL, NULL, NULL);
 106
 107 #define SRP_PID(p) \
 108         (p)->port_id[0], (p)->port_id[1], (p)->port_id[2], (p)->port_id[3], \
 109         (p)->port_id[4], (p)->port_id[5], (p)->port_id[6], (p)->port_id[7], \
 110         (p)->port_id[8], (p)->port_id[9], (p)->port_id[10], (p)->port_id[11], \
 111         (p)->port_id[12], (p)->port_id[13], (p)->port_id[14], (p)->port_id[15]
 112
 113 #define SRP_PID_FMT "%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:" \
 114         "%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x"
 115
 116 static ssize_t
 117 show_srp_rport_id(struct device *dev, struct device_attribute *attr,
 118                   char *buf)
 119 {
 120         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 121         return sprintf(buf, SRP_PID_FMT "\n", SRP_PID(rport));
 122 }
 123
 124 static DEVICE_ATTR(port_id, S_IRUGO, show_srp_rport_id, NULL);
 125
 126 static const struct {
 127         u32 value;
 128         char *name;
 129 } srp_rport_role_names[] = {
 130         {SRP_RPORT_ROLE_INITIATOR, "SRP Initiator"},
 131         {SRP_RPORT_ROLE_TARGET, "SRP Target"},
 132 };
 133
 134 static ssize_t
 135 show_srp_rport_roles(struct device *dev, struct device_attribute *attr,
 136                      char *buf)
 137 {
 138         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 139         int i;
 140         char *name = NULL;
 141
 142         for (i = 0; i < ARRAY_SIZE(srp_rport_role_names); i++)
 143                 if (srp_rport_role_names[i].value == rport->roles) {
 144                         name = srp_rport_role_names[i].name;
 145                         break;
 146                 }
 147         return sprintf(buf, "%s\n", name ? : "unknown");
 148 }
 149
 150 static DEVICE_ATTR(roles, S_IRUGO, show_srp_rport_roles, NULL);
 151
 152 static ssize_t store_srp_rport_delete(struct device *dev,
 153                                       struct device_attribute *attr,
 154                                       const char *buf, size_t count)
 155 {
 156         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 157         struct Scsi_Host *shost = dev_to_shost(dev);
 158         struct srp_internal *i = to_srp_internal(shost->transportt);
 159
 160         if (i->f->rport_delete) {
 161                 i->f->rport_delete(rport);
 162                 return count;
 163         } else {
 164                 return -ENOSYS;
 165         }
 166 }
 167
 168 static DEVICE_ATTR(delete, S_IWUSR, NULL, store_srp_rport_delete);
 169
 170 static ssize_t show_srp_rport_state(struct device *dev,
 171                                     struct device_attribute *attr,
 172                                     char *buf)
 173 {
 174         static const char *const state_name[] = {
 175                 [SRP_RPORT_RUNNING]     = "running",
 176                 [SRP_RPORT_BLOCKED]     = "blocked",
 177                 [SRP_RPORT_FAIL_FAST]   = "fail-fast",
 178                 [SRP_RPORT_LOST]        = "lost",
 179         };
 180         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 181         enum srp_rport_state state = rport->state;
 182
 183         return sprintf(buf, "%s\n",
 184                        (unsigned)state < ARRAY_SIZE(state_name) ?
 185                        state_name[state] : "???");
 186 }
 187
 188 static DEVICE_ATTR(state, S_IRUGO, show_srp_rport_state, NULL);
 189
 190 static ssize_t srp_show_tmo(char *buf, int tmo)
 191 {
 192         return tmo >= 0 ? sprintf(buf, "%d\n", tmo) : sprintf(buf, "off\n");
 193 }
 194
 195 static int srp_parse_tmo(int *tmo, const char *buf)
 196 {
 197         int res = 0;
 198
 199         if (strncmp(buf, "off", 3) != 0)
 200                 res = kstrtoint(buf, 0, tmo);
 201         else
 202                 *tmo = -1;
 203
 204         return res;
 205 }
 206
 207 static ssize_t show_reconnect_delay(struct device *dev,
 208                                     struct device_attribute *attr, char *buf)
 209 {
 210         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 211
 212         return srp_show_tmo(buf, rport->reconnect_delay);
 213 }
 214
 215 static ssize_t store_reconnect_delay(struct device *dev,
 216                                      struct device_attribute *attr,
 217                                      const char *buf, const size_t count)
 218 {
 219         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 220         int res, delay;
 221
 222         res = srp_parse_tmo(&delay, buf);
 223         if (res)
 224                 goto out;
 225         res = srp_tmo_valid(delay, rport->fast_io_fail_tmo,
 226                             rport->dev_loss_tmo);
 227         if (res)
 228                 goto out;
 229
 230         if (rport->reconnect_delay <= 0 && delay > 0 &&
 231             rport->state != SRP_RPORT_RUNNING) {
 232                 queue_delayed_work(system_long_wq, &rport->reconnect_work,
 233                                    delay * HZ);
 234         } else if (delay <= 0) {
 235                 cancel_delayed_work(&rport->reconnect_work);
 236         }
 237         rport->reconnect_delay = delay;
 238         res = count;
 239
 240 out:
 241         return res;
 242 }
 243
 244 static DEVICE_ATTR(reconnect_delay, S_IRUGO | S_IWUSR, show_reconnect_delay,
 245                    store_reconnect_delay);
 246
 247 static ssize_t show_failed_reconnects(struct device *dev,
 248                                       struct device_attribute *attr, char *buf)
 249 {
 250         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 251
 252         return sprintf(buf, "%d\n", rport->failed_reconnects);
 253 }
 254
 255 static DEVICE_ATTR(failed_reconnects, S_IRUGO, show_failed_reconnects, NULL);
 256
 257 static ssize_t show_srp_rport_fast_io_fail_tmo(struct device *dev,
 258                                                struct device_attribute *attr,
 259                                                char *buf)
 260 {
 261         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 262
 263         return srp_show_tmo(buf, rport->fast_io_fail_tmo);
 264 }
 265
 266 static ssize_t store_srp_rport_fast_io_fail_tmo(struct device *dev,
 267                                                 struct device_attribute *attr,
 268                                                 const char *buf, size_t count)
 269 {
 270         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 271         int res;
 272         int fast_io_fail_tmo;
 273
 274         res = srp_parse_tmo(&fast_io_fail_tmo, buf);
 275         if (res)
 276                 goto out;
 277         res = srp_tmo_valid(rport->reconnect_delay, fast_io_fail_tmo,
 278                             rport->dev_loss_tmo);
 279         if (res)
 280                 goto out;
 281         rport->fast_io_fail_tmo = fast_io_fail_tmo;
 282         res = count;
 283
 284 out:
 285         return res;
 286 }
 287
 288 static DEVICE_ATTR(fast_io_fail_tmo, S_IRUGO | S_IWUSR,
 289                    show_srp_rport_fast_io_fail_tmo,
 290                    store_srp_rport_fast_io_fail_tmo);
 291
 292 static ssize_t show_srp_rport_dev_loss_tmo(struct device *dev,
 293                                            struct device_attribute *attr,
 294                                            char *buf)
 295 {
 296         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 297
 298         return srp_show_tmo(buf, rport->dev_loss_tmo);
 299 }
 300
 301 static ssize_t store_srp_rport_dev_loss_tmo(struct device *dev,
 302                                             struct device_attribute *attr,
 303                                             const char *buf, size_t count)
 304 {
 305         struct srp_rport *rport = transport_class_to_srp_rport(dev);
 306         int res;
 307         int dev_loss_tmo;
 308
 309         res = srp_parse_tmo(&dev_loss_tmo, buf);
 310         if (res)
 311                 goto out;
 312         res = srp_tmo_valid(rport->reconnect_delay, rport->fast_io_fail_tmo,
 313                             dev_loss_tmo);
 314         if (res)
 315                 goto out;
 316         rport->dev_loss_tmo = dev_loss_tmo;
 317         res = count;
 318
 319 out:
 320         return res;
 321 }
 322
 323 static DEVICE_ATTR(dev_loss_tmo, S_IRUGO | S_IWUSR,
 324                    show_srp_rport_dev_loss_tmo,
 325                    store_srp_rport_dev_loss_tmo);
 326
 327 static int srp_rport_set_state(struct srp_rport *rport,
 328                                enum srp_rport_state new_state)
 329 {
 330         enum srp_rport_state old_state = rport->state;
 331
 332         lockdep_assert_held(&rport->mutex);
 333
 334         switch (new_state) {
 335         case SRP_RPORT_RUNNING:
 336                 switch (old_state) {
 337                 case SRP_RPORT_LOST:
 338                         goto invalid;
 339                 default:
 340                         break;
 341                 }
 342                 break;
 343         case SRP_RPORT_BLOCKED:
 344                 switch (old_state) {
 345                 case SRP_RPORT_RUNNING:
 346                         break;
 347                 default:
 348                         goto invalid;
 349                 }
 350                 break;
 351         case SRP_RPORT_FAIL_FAST:
 352                 switch (old_state) {
 353                 case SRP_RPORT_LOST:
 354                         goto invalid;
 355                 default:
 356                         break;
 357                 }
 358                 break;
 359         case SRP_RPORT_LOST:
 360                 break;
 361         }
 362         rport->state = new_state;
 363         return 0;
 364
 365 invalid:
 366         return -EINVAL;
 367 }
 368
 369 /**
 370  * srp_reconnect_work() - reconnect and schedule a new attempt if necessary
 371  */
 372 static void srp_reconnect_work(struct work_struct *work)
 373 {
 374         struct srp_rport *rport = container_of(to_delayed_work(work),
 375                                         struct srp_rport, reconnect_work);
 376         struct Scsi_Host *shost = rport_to_shost(rport);
 377         int delay, res;
 378
 379         res = srp_reconnect_rport(rport);
 380         if (res != 0) {
 381                 shost_printk(KERN_ERR, shost,
 382                              "reconnect attempt %d failed (%d)\n",
 383                              ++rport->failed_reconnects, res);
 384                 delay = rport->reconnect_delay *
 385                         min(100, max(1, rport->failed_reconnects - 10));
 386                 if (delay > 0)
 387                         queue_delayed_work(system_long_wq,
 388                                            &rport->reconnect_work, delay * HZ);
 389         }
 390 }
 391
 392 static void __rport_fail_io_fast(struct srp_rport *rport)
 393 {
 394         struct Scsi_Host *shost = rport_to_shost(rport);
 395         struct srp_internal *i;
 396
 397         lockdep_assert_held(&rport->mutex);
 398
 399         if (srp_rport_set_state(rport, SRP_RPORT_FAIL_FAST))
 400                 return;
 401         scsi_target_unblock(rport->dev.parent, SDEV_TRANSPORT_OFFLINE);
 402
 403         /* Involve the LLD if possible to terminate all I/O on the rport. */
 404         i = to_srp_internal(shost->transportt);
 405         if (i->f->terminate_rport_io)
 406                 i->f->terminate_rport_io(rport);
 407 }
 408
 409 /**
 410  * rport_fast_io_fail_timedout() - fast I/O failure timeout handler
 411  */
 412 static void rport_fast_io_fail_timedout(struct work_struct *work)
 413 {
 414         struct srp_rport *rport = container_of(to_delayed_work(work),
 415                                         struct srp_rport, fast_io_fail_work);
 416         struct Scsi_Host *shost = rport_to_shost(rport);
 417
 418         pr_info("fast_io_fail_tmo expired for SRP %s / %s.\n",
 419                 dev_name(&rport->dev), dev_name(&shost->shost_gendev));
 420
 421         mutex_lock(&rport->mutex);
 422         if (rport->state == SRP_RPORT_BLOCKED)
 423                 __rport_fail_io_fast(rport);
 424         mutex_unlock(&rport->mutex);
 425 }
 426
 427 /**
 428  * rport_dev_loss_timedout() - device loss timeout handler
 429  */
 430 static void rport_dev_loss_timedout(struct work_struct *work)
 431 {
 432         struct srp_rport *rport = container_of(to_delayed_work(work),
 433                                         struct srp_rport, dev_loss_work);
 434         struct Scsi_Host *shost = rport_to_shost(rport);
 435         struct srp_internal *i = to_srp_internal(shost->transportt);
 436
 437         pr_info("dev_loss_tmo expired for SRP %s / %s.\n",
 438                 dev_name(&rport->dev), dev_name(&shost->shost_gendev));
 439
 440         mutex_lock(&rport->mutex);
 441         WARN_ON(srp_rport_set_state(rport, SRP_RPORT_LOST) != 0);
 442         scsi_target_unblock(rport->dev.parent, SDEV_TRANSPORT_OFFLINE);
 443         mutex_unlock(&rport->mutex);
 444
 445         i->f->rport_delete(rport);
 446 }
 447
 448 static void __srp_start_tl_fail_timers(struct srp_rport *rport)
 449 {
 450         struct Scsi_Host *shost = rport_to_shost(rport);
 451         int delay, fast_io_fail_tmo, dev_loss_tmo;
 452
 453         lockdep_assert_held(&rport->mutex);
 454
 455         if (!rport->deleted) {
 456                 delay = rport->reconnect_delay;
 457                 fast_io_fail_tmo = rport->fast_io_fail_tmo;
 458                 dev_loss_tmo = rport->dev_loss_tmo;
 459                 pr_debug("%s current state: %d\n",
 460                          dev_name(&shost->shost_gendev), rport->state);
 461
 462                 if (delay > 0)
 463                         queue_delayed_work(system_long_wq,
 464                                            &rport->reconnect_work,
 465                                            1UL * delay * HZ);
 466                 if (fast_io_fail_tmo >= 0 &&
 467                     srp_rport_set_state(rport, SRP_RPORT_BLOCKED) == 0) {
 468                         pr_debug("%s new state: %d\n",
 469                                  dev_name(&shost->shost_gendev),
 470                                  rport->state);
 471                         scsi_target_block(&shost->shost_gendev);
 472                         queue_delayed_work(system_long_wq,
 473                                            &rport->fast_io_fail_work,
 474                                            1UL * fast_io_fail_tmo * HZ);
 475                 }
 476                 if (dev_loss_tmo >= 0)
 477                         queue_delayed_work(system_long_wq,
 478                                            &rport->dev_loss_work,
 479                                            1UL * dev_loss_tmo * HZ);
 480         } else {
 481                 pr_debug("%s has already been deleted\n",
 482                          dev_name(&shost->shost_gendev));
 483                 srp_rport_set_state(rport, SRP_RPORT_FAIL_FAST);
 484                 scsi_target_unblock(&shost->shost_gendev,
 485                                     SDEV_TRANSPORT_OFFLINE);
 486         }
 487 }
 488
 489 /**
 490  * srp_start_tl_fail_timers() - start the transport layer failure timers
 491  *
 492  * Start the transport layer fast I/O failure and device loss timers. Do not
 493  * modify a timer that was already started.
 494  */
 495 void srp_start_tl_fail_timers(struct srp_rport *rport)
 496 {
 497         mutex_lock(&rport->mutex);
 498         __srp_start_tl_fail_timers(rport);
 499         mutex_unlock(&rport->mutex);
 500 }
 501 EXPORT_SYMBOL(srp_start_tl_fail_timers);
 502
 503 /**
 504  * scsi_request_fn_active() - number of kernel threads inside scsi_request_fn()
 505  */
 506 static int scsi_request_fn_active(struct Scsi_Host *shost)
 507 {
 508         struct scsi_device *sdev;
 509         struct request_queue *q;
 510         int request_fn_active = 0;
 511
 512         shost_for_each_device(sdev, shost) {
 513                 q = sdev->request_queue;
 514
 515                 spin_lock_irq(q->queue_lock);
 516                 request_fn_active += q->request_fn_active;
 517                 spin_unlock_irq(q->queue_lock);
 518         }
 519
 520         return request_fn_active;
 521 }
 522
 523 /**
 524  * srp_reconnect_rport() - reconnect to an SRP target port
 525  *
 526  * Blocks SCSI command queueing before invoking reconnect() such that
 527  * queuecommand() won't be invoked concurrently with reconnect() from outside
 528  * the SCSI EH. This is important since a reconnect() implementation may
 529  * reallocate resources needed by queuecommand().
 530  *
 531  * Notes:
 532  * - This function neither waits until outstanding requests have finished nor
 533  *   tries to abort these. It is the responsibility of the reconnect()
 534  *   function to finish outstanding commands before reconnecting to the target
 535  *   port.
 536  * - It is the responsibility of the caller to ensure that the resources
 537  *   reallocated by the reconnect() function won't be used while this function
 538  *   is in progress. One possible strategy is to invoke this function from
 539  *   the context of the SCSI EH thread only. Another possible strategy is to
 540  *   lock the rport mutex inside each SCSI LLD callback that can be invoked by
 541  *   the SCSI EH (the scsi_host_template.eh_*() functions and also the
 542  *   scsi_host_template.queuecommand() function).
 543  */
 544 int srp_reconnect_rport(struct srp_rport *rport)
 545 {
 546         struct Scsi_Host *shost = rport_to_shost(rport);
 547         struct srp_internal *i = to_srp_internal(shost->transportt);
 548         struct scsi_device *sdev;
 549         int res;
 550
 551         pr_debug("SCSI host %s\n", dev_name(&shost->shost_gendev));
 552
 553         res = mutex_lock_interruptible(&rport->mutex);
 554         if (res)
 555                 goto out;
 556         scsi_target_block(&shost->shost_gendev);
 557         while (scsi_request_fn_active(shost))
 558                 msleep(20);
 559         res = i->f->reconnect(rport);
 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                 spin_lock_irq(shost->host_lock);
 575                 __shost_for_each_device(sdev, shost)
 576                         if (sdev->sdev_state == SDEV_OFFLINE)
 577                                 sdev->sdev_state = SDEV_RUNNING;
 578                 spin_unlock_irq(shost->host_lock);
 579         } else if (rport->state == SRP_RPORT_RUNNING) {
 580                 /*
 581                  * srp_reconnect_rport() was invoked with fast_io_fail
 582                  * off. Mark the port as failed and start the TL failure
 583                  * timers if these had not yet been started.
 584                  */
 585                 __rport_fail_io_fast(rport);
 586                 scsi_target_unblock(&shost->shost_gendev,
 587                                     SDEV_TRANSPORT_OFFLINE);
 588                 __srp_start_tl_fail_timers(rport);
 589         } else if (rport->state != SRP_RPORT_BLOCKED) {
 590                 scsi_target_unblock(&shost->shost_gendev,
 591                                     SDEV_TRANSPORT_OFFLINE);
 592         }
 593         mutex_unlock(&rport->mutex);
 594
 595 out:
 596         return res;
 597 }
 598 EXPORT_SYMBOL(srp_reconnect_rport);
 599
 600 /**
 601  * srp_timed_out() - SRP transport intercept of the SCSI timeout EH
 602  *
 603  * If a timeout occurs while an rport is in the blocked state, ask the SCSI
 604  * EH to continue waiting (BLK_EH_RESET_TIMER). Otherwise let the SCSI core
 605  * handle the timeout (BLK_EH_NOT_HANDLED).
 606  *
 607  * Note: This function is called from soft-IRQ context and with the request
 608  * queue lock held.
 609  */
 610 static enum blk_eh_timer_return srp_timed_out(struct scsi_cmnd *scmd)
 611 {
 612         struct scsi_device *sdev = scmd->device;
 613         struct Scsi_Host *shost = sdev->host;
 614         struct srp_internal *i = to_srp_internal(shost->transportt);
 615
 616         pr_debug("timeout for sdev %s\n", dev_name(&sdev->sdev_gendev));
 617         return i->f->reset_timer_if_blocked && scsi_device_blocked(sdev) ?
 618                 BLK_EH_RESET_TIMER : BLK_EH_NOT_HANDLED;
 619 }
 620
 621 static void srp_rport_release(struct device *dev)
 622 {
 623         struct srp_rport *rport = dev_to_rport(dev);
 624
 625         cancel_delayed_work_sync(&rport->reconnect_work);
 626         cancel_delayed_work_sync(&rport->fast_io_fail_work);
 627         cancel_delayed_work_sync(&rport->dev_loss_work);
 628
 629         put_device(dev->parent);
 630         kfree(rport);
 631 }
 632
 633 static int scsi_is_srp_rport(const struct device *dev)
 634 {
 635         return dev->release == srp_rport_release;
 636 }
 637
 638 static int srp_rport_match(struct attribute_container *cont,
 639                            struct device *dev)
 640 {
 641         struct Scsi_Host *shost;
 642         struct srp_internal *i;
 643
 644         if (!scsi_is_srp_rport(dev))
 645                 return 0;
 646
 647         shost = dev_to_shost(dev->parent);
 648         if (!shost->transportt)
 649                 return 0;
 650         if (shost->transportt->host_attrs.ac.class != &srp_host_class.class)
 651                 return 0;
 652
 653         i = to_srp_internal(shost->transportt);
 654         return &i->rport_attr_cont.ac == cont;
 655 }
 656
 657 static int srp_host_match(struct attribute_container *cont, struct device *dev)
 658 {
 659         struct Scsi_Host *shost;
 660         struct srp_internal *i;
 661
 662         if (!scsi_is_host_device(dev))
 663                 return 0;
 664
 665         shost = dev_to_shost(dev);
 666         if (!shost->transportt)
 667                 return 0;
 668         if (shost->transportt->host_attrs.ac.class != &srp_host_class.class)
 669                 return 0;
 670
 671         i = to_srp_internal(shost->transportt);
 672         return &i->t.host_attrs.ac == cont;
 673 }
 674
 675 /**
 676  * srp_rport_get() - increment rport reference count
 677  */
 678 void srp_rport_get(struct srp_rport *rport)
 679 {
 680         get_device(&rport->dev);
 681 }
 682 EXPORT_SYMBOL(srp_rport_get);
 683
 684 /**
 685  * srp_rport_put() - decrement rport reference count
 686  */
 687 void srp_rport_put(struct srp_rport *rport)
 688 {
 689         put_device(&rport->dev);
 690 }
 691 EXPORT_SYMBOL(srp_rport_put);
 692
 693 /**
 694  * srp_rport_add - add a SRP remote port to the device hierarchy
 695  * @shost:      scsi host the remote port is connected to.
 696  * @ids:        The port id for the remote port.
 697  *
 698  * Publishes a port to the rest of the system.
 699  */
 700 struct srp_rport *srp_rport_add(struct Scsi_Host *shost,
 701                                 struct srp_rport_identifiers *ids)
 702 {
 703         struct srp_rport *rport;
 704         struct device *parent = &shost->shost_gendev;
 705         struct srp_internal *i = to_srp_internal(shost->transportt);
 706         int id, ret;
 707
 708         rport = kzalloc(sizeof(*rport), GFP_KERNEL);
 709         if (!rport)
 710                 return ERR_PTR(-ENOMEM);
 711
 712         mutex_init(&rport->mutex);
 713
 714         device_initialize(&rport->dev);
 715
 716         rport->dev.parent = get_device(parent);
 717         rport->dev.release = srp_rport_release;
 718
 719         memcpy(rport->port_id, ids->port_id, sizeof(rport->port_id));
 720         rport->roles = ids->roles;
 721
 722         if (i->f->reconnect)
 723                 rport->reconnect_delay = i->f->reconnect_delay ?
 724                         *i->f->reconnect_delay : 10;
 725         INIT_DELAYED_WORK(&rport->reconnect_work, srp_reconnect_work);
 726         rport->fast_io_fail_tmo = i->f->fast_io_fail_tmo ?
 727                 *i->f->fast_io_fail_tmo : 15;
 728         rport->dev_loss_tmo = i->f->dev_loss_tmo ? *i->f->dev_loss_tmo : 60;
 729         INIT_DELAYED_WORK(&rport->fast_io_fail_work,
 730                           rport_fast_io_fail_timedout);
 731         INIT_DELAYED_WORK(&rport->dev_loss_work, rport_dev_loss_timedout);
 732
 733         id = atomic_inc_return(&to_srp_host_attrs(shost)->next_port_id);
 734         dev_set_name(&rport->dev, "port-%d:%d", shost->host_no, id);
 735
 736         transport_setup_device(&rport->dev);
 737
 738         ret = device_add(&rport->dev);
 739         if (ret) {
 740                 transport_destroy_device(&rport->dev);
 741                 put_device(&rport->dev);
 742                 return ERR_PTR(ret);
 743         }
 744
 745         if (shost->active_mode & MODE_TARGET &&
 746             ids->roles == SRP_RPORT_ROLE_INITIATOR) {
 747                 ret = srp_tgt_it_nexus_create(shost, (unsigned long)rport,
 748                                               rport->port_id);
 749                 if (ret) {
 750                         device_del(&rport->dev);
 751                         transport_destroy_device(&rport->dev);
 752                         put_device(&rport->dev);
 753                         return ERR_PTR(ret);
 754                 }
 755         }
 756
 757         transport_add_device(&rport->dev);
 758         transport_configure_device(&rport->dev);
 759
 760         return rport;
 761 }
 762 EXPORT_SYMBOL_GPL(srp_rport_add);
 763
 764 /**
 765  * srp_rport_del  -  remove a SRP remote port
 766  * @rport:      SRP remote port to remove
 767  *
 768  * Removes the specified SRP remote port.
 769  */
 770 void srp_rport_del(struct srp_rport *rport)
 771 {
 772         struct device *dev = &rport->dev;
 773         struct Scsi_Host *shost = dev_to_shost(dev->parent);
 774
 775         if (shost->active_mode & MODE_TARGET &&
 776             rport->roles == SRP_RPORT_ROLE_INITIATOR)
 777                 srp_tgt_it_nexus_destroy(shost, (unsigned long)rport);
 778
 779         transport_remove_device(dev);
 780         device_del(dev);
 781         transport_destroy_device(dev);
 782
 783         mutex_lock(&rport->mutex);
 784         if (rport->state == SRP_RPORT_BLOCKED)
 785                 __rport_fail_io_fast(rport);
 786         rport->deleted = true;
 787         mutex_unlock(&rport->mutex);
 788
 789         put_device(dev);
 790 }
 791 EXPORT_SYMBOL_GPL(srp_rport_del);
 792
 793 static int do_srp_rport_del(struct device *dev, void *data)
 794 {
 795         if (scsi_is_srp_rport(dev))
 796                 srp_rport_del(dev_to_rport(dev));
 797         return 0;
 798 }
 799
 800 /**
 801  * srp_remove_host  -  tear down a Scsi_Host's SRP data structures
 802  * @shost:      Scsi Host that is torn down
 803  *
 804  * Removes all SRP remote ports for a given Scsi_Host.
 805  * Must be called just before scsi_remove_host for SRP HBAs.
 806  */
 807 void srp_remove_host(struct Scsi_Host *shost)
 808 {
 809         device_for_each_child(&shost->shost_gendev, NULL, do_srp_rport_del);
 810 }
 811 EXPORT_SYMBOL_GPL(srp_remove_host);
 812
 813 static int srp_tsk_mgmt_response(struct Scsi_Host *shost, u64 nexus, u64 tm_id,
 814                                  int result)
 815 {
 816         struct srp_internal *i = to_srp_internal(shost->transportt);
 817         return i->f->tsk_mgmt_response(shost, nexus, tm_id, result);
 818 }
 819
 820 static int srp_it_nexus_response(struct Scsi_Host *shost, u64 nexus, int result)
 821 {
 822         struct srp_internal *i = to_srp_internal(shost->transportt);
 823         return i->f->it_nexus_response(shost, nexus, result);
 824 }
 825
 826 /**
 827  * srp_attach_transport  -  instantiate SRP transport template
 828  * @ft:         SRP transport class function template
 829  */
 830 struct scsi_transport_template *
 831 srp_attach_transport(struct srp_function_template *ft)
 832 {
 833         int count;
 834         struct srp_internal *i;
 835
 836         i = kzalloc(sizeof(*i), GFP_KERNEL);
 837         if (!i)
 838                 return NULL;
 839
 840         i->t.eh_timed_out = srp_timed_out;
 841
 842         i->t.tsk_mgmt_response = srp_tsk_mgmt_response;
 843         i->t.it_nexus_response = srp_it_nexus_response;
 844
 845         i->t.host_size = sizeof(struct srp_host_attrs);
 846         i->t.host_attrs.ac.attrs = &i->host_attrs[0];
 847         i->t.host_attrs.ac.class = &srp_host_class.class;
 848         i->t.host_attrs.ac.match = srp_host_match;
 849         i->host_attrs[0] = NULL;
 850         transport_container_register(&i->t.host_attrs);
 851
 852         i->rport_attr_cont.ac.attrs = &i->rport_attrs[0];
 853         i->rport_attr_cont.ac.class = &srp_rport_class.class;
 854         i->rport_attr_cont.ac.match = srp_rport_match;
 855
 856         count = 0;
 857         i->rport_attrs[count++] = &dev_attr_port_id;
 858         i->rport_attrs[count++] = &dev_attr_roles;
 859         if (ft->has_rport_state) {
 860                 i->rport_attrs[count++] = &dev_attr_state;
 861                 i->rport_attrs[count++] = &dev_attr_fast_io_fail_tmo;
 862                 i->rport_attrs[count++] = &dev_attr_dev_loss_tmo;
 863         }
 864         if (ft->reconnect) {
 865                 i->rport_attrs[count++] = &dev_attr_reconnect_delay;
 866                 i->rport_attrs[count++] = &dev_attr_failed_reconnects;
 867         }
 868         if (ft->rport_delete)
 869                 i->rport_attrs[count++] = &dev_attr_delete;
 870         i->rport_attrs[count++] = NULL;
 871         BUG_ON(count > ARRAY_SIZE(i->rport_attrs));
 872
 873         transport_container_register(&i->rport_attr_cont);
 874
 875         i->f = ft;
 876
 877         return &i->t;
 878 }
 879 EXPORT_SYMBOL_GPL(srp_attach_transport);
 880
 881 /**
 882  * srp_release_transport  -  release SRP transport template instance
 883  * @t:          transport template instance
 884  */
 885 void srp_release_transport(struct scsi_transport_template *t)
 886 {
 887         struct srp_internal *i = to_srp_internal(t);
 888
 889         transport_container_unregister(&i->t.host_attrs);
 890         transport_container_unregister(&i->rport_attr_cont);
 891
 892         kfree(i);
 893 }
 894 EXPORT_SYMBOL_GPL(srp_release_transport);
 895
 896 static __init int srp_transport_init(void)
 897 {
 898         int ret;
 899
 900         ret = transport_class_register(&srp_host_class);
 901         if (ret)
 902                 return ret;
 903         ret = transport_class_register(&srp_rport_class);
 904         if (ret)
 905                 goto unregister_host_class;
 906
 907         return 0;
 908 unregister_host_class:
 909         transport_class_unregister(&srp_host_class);
 910         return ret;
 911 }
 912
 913 static void __exit srp_transport_exit(void)
 914 {
 915         transport_class_unregister(&srp_host_class);
 916         transport_class_unregister(&srp_rport_class);
 917 }
 918
 919 MODULE_AUTHOR("FUJITA Tomonori");
 920 MODULE_DESCRIPTION("SRP Transport Attributes");
 921 MODULE_LICENSE("GPL");
 922
 923 module_init(srp_transport_init);
 924 module_exit(srp_transport_exit);