drivers/nvme/host/multipath.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (c) 2017-2018 Christoph Hellwig.
   4  */
   5
   6 #include <linux/backing-dev.h>
   7 #include <linux/moduleparam.h>
   8 #include <trace/events/block.h>
   9 #include "nvme.h"
  10
  11 static bool multipath = true;
  12 module_param(multipath, bool, 0444);
  13 MODULE_PARM_DESC(multipath,
  14         "turn on native support for multiple controllers per subsystem");
  15
  16 void nvme_mpath_unfreeze(struct nvme_subsystem *subsys)
  17 {
  18         struct nvme_ns_head *h;
  19
  20         lockdep_assert_held(&subsys->lock);
  21         list_for_each_entry(h, &subsys->nsheads, entry)
  22                 if (h->disk)
  23                         blk_mq_unfreeze_queue(h->disk->queue);
  24 }
  25
  26 void nvme_mpath_wait_freeze(struct nvme_subsystem *subsys)
  27 {
  28         struct nvme_ns_head *h;
  29
  30         lockdep_assert_held(&subsys->lock);
  31         list_for_each_entry(h, &subsys->nsheads, entry)
  32                 if (h->disk)
  33                         blk_mq_freeze_queue_wait(h->disk->queue);
  34 }
  35
  36 void nvme_mpath_start_freeze(struct nvme_subsystem *subsys)
  37 {
  38         struct nvme_ns_head *h;
  39
  40         lockdep_assert_held(&subsys->lock);
  41         list_for_each_entry(h, &subsys->nsheads, entry)
  42                 if (h->disk)
  43                         blk_freeze_queue_start(h->disk->queue);
  44 }
  45
  46 /*
  47  * If multipathing is enabled we need to always use the subsystem instance
  48  * number for numbering our devices to avoid conflicts between subsystems that
  49  * have multiple controllers and thus use the multipath-aware subsystem node
  50  * and those that have a single controller and use the controller node
  51  * directly.
  52  */
  53 void nvme_set_disk_name(char *disk_name, struct nvme_ns *ns,
  54                         struct nvme_ctrl *ctrl, int *flags)
  55 {
  56         if (!multipath) {
  57                 sprintf(disk_name, "nvme%dn%d", ctrl->instance, ns->head->instance);
  58         } else if (ns->head->disk) {
  59                 sprintf(disk_name, "nvme%dc%dn%d", ctrl->subsys->instance,
  60                                 ctrl->instance, ns->head->instance);
  61                 *flags = GENHD_FL_HIDDEN;
  62         } else {
  63                 sprintf(disk_name, "nvme%dn%d", ctrl->subsys->instance,
  64                                 ns->head->instance);
  65         }
  66 }
  67
  68 void nvme_failover_req(struct request *req)
  69 {
  70         struct nvme_ns *ns = req->q->queuedata;
  71         u16 status = nvme_req(req)->status & 0x7ff;
  72         unsigned long flags;
  73
  74         nvme_mpath_clear_current_path(ns);
  75
  76         /*
  77          * If we got back an ANA error, we know the controller is alive but not
  78          * ready to serve this namespace.  Kick of a re-read of the ANA
  79          * information page, and just try any other available path for now.
  80          */
  81         if (nvme_is_ana_error(status) && ns->ctrl->ana_log_buf) {
  82                 set_bit(NVME_NS_ANA_PENDING, &ns->flags);
  83                 queue_work(nvme_wq, &ns->ctrl->ana_work);
  84         }
  85
  86         spin_lock_irqsave(&ns->head->requeue_lock, flags);
  87         blk_steal_bios(&ns->head->requeue_list, req);
  88         spin_unlock_irqrestore(&ns->head->requeue_lock, flags);
  89
  90         blk_mq_end_request(req, 0);
  91         kblockd_schedule_work(&ns->head->requeue_work);
  92 }
  93
  94 void nvme_kick_requeue_lists(struct nvme_ctrl *ctrl)
  95 {
  96         struct nvme_ns *ns;
  97
  98         down_read(&ctrl->namespaces_rwsem);
  99         list_for_each_entry(ns, &ctrl->namespaces, list) {
 100                 if (ns->head->disk)
 101                         kblockd_schedule_work(&ns->head->requeue_work);
 102         }
 103         up_read(&ctrl->namespaces_rwsem);
 104 }
 105
 106 static const char *nvme_ana_state_names[] = {
 107         [0]                             = "invalid state",
 108         [NVME_ANA_OPTIMIZED]            = "optimized",
 109         [NVME_ANA_NONOPTIMIZED]         = "non-optimized",
 110         [NVME_ANA_INACCESSIBLE]         = "inaccessible",
 111         [NVME_ANA_PERSISTENT_LOSS]      = "persistent-loss",
 112         [NVME_ANA_CHANGE]               = "change",
 113 };
 114
 115 bool nvme_mpath_clear_current_path(struct nvme_ns *ns)
 116 {
 117         struct nvme_ns_head *head = ns->head;
 118         bool changed = false;
 119         int node;
 120
 121         if (!head)
 122                 goto out;
 123
 124         for_each_node(node) {
 125                 if (ns == rcu_access_pointer(head->current_path[node])) {
 126                         rcu_assign_pointer(head->current_path[node], NULL);
 127                         changed = true;
 128                 }
 129         }
 130 out:
 131         return changed;
 132 }
 133
 134 void nvme_mpath_clear_ctrl_paths(struct nvme_ctrl *ctrl)
 135 {
 136         struct nvme_ns *ns;
 137
 138         mutex_lock(&ctrl->scan_lock);
 139         down_read(&ctrl->namespaces_rwsem);
 140         list_for_each_entry(ns, &ctrl->namespaces, list)
 141                 if (nvme_mpath_clear_current_path(ns))
 142                         kblockd_schedule_work(&ns->head->requeue_work);
 143         up_read(&ctrl->namespaces_rwsem);
 144         mutex_unlock(&ctrl->scan_lock);
 145 }
 146
 147 static bool nvme_path_is_disabled(struct nvme_ns *ns)
 148 {
 149         /*
 150          * We don't treat NVME_CTRL_DELETING as a disabled path as I/O should
 151          * still be able to complete assuming that the controller is connected.
 152          * Otherwise it will fail immediately and return to the requeue list.
 153          */
 154         if (ns->ctrl->state != NVME_CTRL_LIVE &&
 155             ns->ctrl->state != NVME_CTRL_DELETING)
 156                 return true;
 157         if (test_bit(NVME_NS_ANA_PENDING, &ns->flags) ||
 158             test_bit(NVME_NS_REMOVING, &ns->flags))
 159                 return true;
 160         return false;
 161 }
 162
 163 static struct nvme_ns *__nvme_find_path(struct nvme_ns_head *head, int node)
 164 {
 165         int found_distance = INT_MAX, fallback_distance = INT_MAX, distance;
 166         struct nvme_ns *found = NULL, *fallback = NULL, *ns;
 167
 168         list_for_each_entry_rcu(ns, &head->list, siblings) {
 169                 if (nvme_path_is_disabled(ns))
 170                         continue;
 171
 172                 if (READ_ONCE(head->subsys->iopolicy) == NVME_IOPOLICY_NUMA)
 173                         distance = node_distance(node, ns->ctrl->numa_node);
 174                 else
 175                         distance = LOCAL_DISTANCE;
 176
 177                 switch (ns->ana_state) {
 178                 case NVME_ANA_OPTIMIZED:
 179                         if (distance < found_distance) {
 180                                 found_distance = distance;
 181                                 found = ns;
 182                         }
 183                         break;
 184                 case NVME_ANA_NONOPTIMIZED:
 185                         if (distance < fallback_distance) {
 186                                 fallback_distance = distance;
 187                                 fallback = ns;
 188                         }
 189                         break;
 190                 default:
 191                         break;
 192                 }
 193         }
 194
 195         if (!found)
 196                 found = fallback;
 197         if (found)
 198                 rcu_assign_pointer(head->current_path[node], found);
 199         return found;
 200 }
 201
 202 static struct nvme_ns *nvme_next_ns(struct nvme_ns_head *head,
 203                 struct nvme_ns *ns)
 204 {
 205         ns = list_next_or_null_rcu(&head->list, &ns->siblings, struct nvme_ns,
 206                         siblings);
 207         if (ns)
 208                 return ns;
 209         return list_first_or_null_rcu(&head->list, struct nvme_ns, siblings);
 210 }
 211
 212 static struct nvme_ns *nvme_round_robin_path(struct nvme_ns_head *head,
 213                 int node, struct nvme_ns *old)
 214 {
 215         struct nvme_ns *ns, *found = NULL;
 216
 217         if (list_is_singular(&head->list)) {
 218                 if (nvme_path_is_disabled(old))
 219                         return NULL;
 220                 return old;
 221         }
 222
 223         for (ns = nvme_next_ns(head, old);
 224              ns != old;
 225              ns = nvme_next_ns(head, ns)) {
 226                 if (nvme_path_is_disabled(ns))
 227                         continue;
 228
 229                 if (ns->ana_state == NVME_ANA_OPTIMIZED) {
 230                         found = ns;
 231                         goto out;
 232                 }
 233                 if (ns->ana_state == NVME_ANA_NONOPTIMIZED)
 234                         found = ns;
 235         }
 236
 237         /*
 238          * The loop above skips the current path for round-robin semantics.
 239          * Fall back to the current path if either:
 240          *  - no other optimized path found and current is optimized,
 241          *  - no other usable path found and current is usable.
 242          */
 243         if (!nvme_path_is_disabled(old) &&
 244             (old->ana_state == NVME_ANA_OPTIMIZED ||
 245              (!found && old->ana_state == NVME_ANA_NONOPTIMIZED)))
 246                 return old;
 247
 248         if (!found)
 249                 return NULL;
 250 out:
 251         rcu_assign_pointer(head->current_path[node], found);
 252         return found;
 253 }
 254
 255 static inline bool nvme_path_is_optimized(struct nvme_ns *ns)
 256 {
 257         return ns->ctrl->state == NVME_CTRL_LIVE &&
 258                 ns->ana_state == NVME_ANA_OPTIMIZED;
 259 }
 260
 261 inline struct nvme_ns *nvme_find_path(struct nvme_ns_head *head)
 262 {
 263         int node = numa_node_id();
 264         struct nvme_ns *ns;
 265
 266         ns = srcu_dereference(head->current_path[node], &head->srcu);
 267         if (unlikely(!ns))
 268                 return __nvme_find_path(head, node);
 269
 270         if (READ_ONCE(head->subsys->iopolicy) == NVME_IOPOLICY_RR)
 271                 return nvme_round_robin_path(head, node, ns);
 272         if (unlikely(!nvme_path_is_optimized(ns)))
 273                 return __nvme_find_path(head, node);
 274         return ns;
 275 }
 276
 277 static bool nvme_available_path(struct nvme_ns_head *head)
 278 {
 279         struct nvme_ns *ns;
 280
 281         list_for_each_entry_rcu(ns, &head->list, siblings) {
 282                 switch (ns->ctrl->state) {
 283                 case NVME_CTRL_LIVE:
 284                 case NVME_CTRL_RESETTING:
 285                 case NVME_CTRL_CONNECTING:
 286                         /* fallthru */
 287                         return true;
 288                 default:
 289                         break;
 290                 }
 291         }
 292         return false;
 293 }
 294
 295 blk_qc_t nvme_ns_head_submit_bio(struct bio *bio)
 296 {
 297         struct nvme_ns_head *head = bio->bi_disk->private_data;
 298         struct device *dev = disk_to_dev(head->disk);
 299         struct nvme_ns *ns;
 300         blk_qc_t ret = BLK_QC_T_NONE;
 301         int srcu_idx;
 302
 303         /*
 304          * The namespace might be going away and the bio might be moved to a
 305          * different queue via blk_steal_bios(), so we need to use the bio_split
 306          * pool from the original queue to allocate the bvecs from.
 307          */
 308         blk_queue_split(&bio);
 309
 310         srcu_idx = srcu_read_lock(&head->srcu);
 311         ns = nvme_find_path(head);
 312         if (likely(ns)) {
 313                 bio->bi_disk = ns->disk;
 314                 bio->bi_opf |= REQ_NVME_MPATH;
 315                 trace_block_bio_remap(bio->bi_disk->queue, bio,
 316                                       disk_devt(ns->head->disk),
 317                                       bio->bi_iter.bi_sector);
 318                 ret = submit_bio_noacct(bio);
 319         } else if (nvme_available_path(head)) {
 320                 dev_warn_ratelimited(dev, "no usable path - requeuing I/O\n");
 321
 322                 spin_lock_irq(&head->requeue_lock);
 323                 bio_list_add(&head->requeue_list, bio);
 324                 spin_unlock_irq(&head->requeue_lock);
 325         } else {
 326                 dev_warn_ratelimited(dev, "no available path - failing I/O\n");
 327
 328                 bio->bi_status = BLK_STS_IOERR;
 329                 bio_endio(bio);
 330         }
 331
 332         srcu_read_unlock(&head->srcu, srcu_idx);
 333         return ret;
 334 }
 335
 336 static void nvme_requeue_work(struct work_struct *work)
 337 {
 338         struct nvme_ns_head *head =
 339                 container_of(work, struct nvme_ns_head, requeue_work);
 340         struct bio *bio, *next;
 341
 342         spin_lock_irq(&head->requeue_lock);
 343         next = bio_list_get(&head->requeue_list);
 344         spin_unlock_irq(&head->requeue_lock);
 345
 346         while ((bio = next) != NULL) {
 347                 next = bio->bi_next;
 348                 bio->bi_next = NULL;
 349
 350                 /*
 351                  * Reset disk to the mpath node and resubmit to select a new
 352                  * path.
 353                  */
 354                 bio->bi_disk = head->disk;
 355                 submit_bio_noacct(bio);
 356         }
 357 }
 358
 359 int nvme_mpath_alloc_disk(struct nvme_ctrl *ctrl, struct nvme_ns_head *head)
 360 {
 361         struct request_queue *q;
 362         bool vwc = false;
 363
 364         mutex_init(&head->lock);
 365         bio_list_init(&head->requeue_list);
 366         spin_lock_init(&head->requeue_lock);
 367         INIT_WORK(&head->requeue_work, nvme_requeue_work);
 368
 369         /*
 370          * Add a multipath node if the subsystems supports multiple controllers.
 371          * We also do this for private namespaces as the namespace sharing data could
 372          * change after a rescan.
 373          */
 374         if (!(ctrl->subsys->cmic & NVME_CTRL_CMIC_MULTI_CTRL) || !multipath)
 375                 return 0;
 376
 377         q = blk_alloc_queue(ctrl->numa_node);
 378         if (!q)
 379                 goto out;
 380         blk_queue_flag_set(QUEUE_FLAG_NONROT, q);
 381         /* set to a default value for 512 until disk is validated */
 382         blk_queue_logical_block_size(q, 512);
 383         blk_set_stacking_limits(&q->limits);
 384
 385         /* we need to propagate up the VMC settings */
 386         if (ctrl->vwc & NVME_CTRL_VWC_PRESENT)
 387                 vwc = true;
 388         blk_queue_write_cache(q, vwc, vwc);
 389
 390         head->disk = alloc_disk(0);
 391         if (!head->disk)
 392                 goto out_cleanup_queue;
 393         head->disk->fops = &nvme_ns_head_ops;
 394         head->disk->private_data = head;
 395         head->disk->queue = q;
 396         head->disk->flags = GENHD_FL_EXT_DEVT;
 397         sprintf(head->disk->disk_name, "nvme%dn%d",
 398                         ctrl->subsys->instance, head->instance);
 399         return 0;
 400
 401 out_cleanup_queue:
 402         blk_cleanup_queue(q);
 403 out:
 404         return -ENOMEM;
 405 }
 406
 407 static void nvme_mpath_set_live(struct nvme_ns *ns)
 408 {
 409         struct nvme_ns_head *head = ns->head;
 410
 411         if (!head->disk)
 412                 return;
 413
 414         if (!test_and_set_bit(NVME_NSHEAD_DISK_LIVE, &head->flags))
 415                 device_add_disk(&head->subsys->dev, head->disk,
 416                                 nvme_ns_id_attr_groups);
 417
 418         mutex_lock(&head->lock);
 419         if (nvme_path_is_optimized(ns)) {
 420                 int node, srcu_idx;
 421
 422                 srcu_idx = srcu_read_lock(&head->srcu);
 423                 for_each_node(node)
 424                         __nvme_find_path(head, node);
 425                 srcu_read_unlock(&head->srcu, srcu_idx);
 426         }
 427         mutex_unlock(&head->lock);
 428
 429         synchronize_srcu(&head->srcu);
 430         kblockd_schedule_work(&head->requeue_work);
 431 }
 432
 433 static int nvme_parse_ana_log(struct nvme_ctrl *ctrl, void *data,
 434                 int (*cb)(struct nvme_ctrl *ctrl, struct nvme_ana_group_desc *,
 435                         void *))
 436 {
 437         void *base = ctrl->ana_log_buf;
 438         size_t offset = sizeof(struct nvme_ana_rsp_hdr);
 439         int error, i;
 440
 441         lockdep_assert_held(&ctrl->ana_lock);
 442
 443         for (i = 0; i < le16_to_cpu(ctrl->ana_log_buf->ngrps); i++) {
 444                 struct nvme_ana_group_desc *desc = base + offset;
 445                 u32 nr_nsids;
 446                 size_t nsid_buf_size;
 447
 448                 if (WARN_ON_ONCE(offset > ctrl->ana_log_size - sizeof(*desc)))
 449                         return -EINVAL;
 450
 451                 nr_nsids = le32_to_cpu(desc->nnsids);
 452                 nsid_buf_size = nr_nsids * sizeof(__le32);
 453
 454                 if (WARN_ON_ONCE(desc->grpid == 0))
 455                         return -EINVAL;
 456                 if (WARN_ON_ONCE(le32_to_cpu(desc->grpid) > ctrl->anagrpmax))
 457                         return -EINVAL;
 458                 if (WARN_ON_ONCE(desc->state == 0))
 459                         return -EINVAL;
 460                 if (WARN_ON_ONCE(desc->state > NVME_ANA_CHANGE))
 461                         return -EINVAL;
 462
 463                 offset += sizeof(*desc);
 464                 if (WARN_ON_ONCE(offset > ctrl->ana_log_size - nsid_buf_size))
 465                         return -EINVAL;
 466
 467                 error = cb(ctrl, desc, data);
 468                 if (error)
 469                         return error;
 470
 471                 offset += nsid_buf_size;
 472         }
 473
 474         return 0;
 475 }
 476
 477 static inline bool nvme_state_is_live(enum nvme_ana_state state)
 478 {
 479         return state == NVME_ANA_OPTIMIZED || state == NVME_ANA_NONOPTIMIZED;
 480 }
 481
 482 static void nvme_update_ns_ana_state(struct nvme_ana_group_desc *desc,
 483                 struct nvme_ns *ns)
 484 {
 485         ns->ana_grpid = le32_to_cpu(desc->grpid);
 486         ns->ana_state = desc->state;
 487         clear_bit(NVME_NS_ANA_PENDING, &ns->flags);
 488
 489         if (nvme_state_is_live(ns->ana_state))
 490                 nvme_mpath_set_live(ns);
 491 }
 492
 493 static int nvme_update_ana_state(struct nvme_ctrl *ctrl,
 494                 struct nvme_ana_group_desc *desc, void *data)
 495 {
 496         u32 nr_nsids = le32_to_cpu(desc->nnsids), n = 0;
 497         unsigned *nr_change_groups = data;
 498         struct nvme_ns *ns;
 499
 500         dev_dbg(ctrl->device, "ANA group %d: %s.\n",
 501                         le32_to_cpu(desc->grpid),
 502                         nvme_ana_state_names[desc->state]);
 503
 504         if (desc->state == NVME_ANA_CHANGE)
 505                 (*nr_change_groups)++;
 506
 507         if (!nr_nsids)
 508                 return 0;
 509
 510         down_read(&ctrl->namespaces_rwsem);
 511         list_for_each_entry(ns, &ctrl->namespaces, list) {
 512                 unsigned nsid = le32_to_cpu(desc->nsids[n]);
 513
 514                 if (ns->head->ns_id < nsid)
 515                         continue;
 516                 if (ns->head->ns_id == nsid)
 517                         nvme_update_ns_ana_state(desc, ns);
 518                 if (++n == nr_nsids)
 519                         break;
 520         }
 521         up_read(&ctrl->namespaces_rwsem);
 522         return 0;
 523 }
 524
 525 static int nvme_read_ana_log(struct nvme_ctrl *ctrl)
 526 {
 527         u32 nr_change_groups = 0;
 528         int error;
 529
 530         mutex_lock(&ctrl->ana_lock);
 531         error = nvme_get_log(ctrl, NVME_NSID_ALL, NVME_LOG_ANA, 0, NVME_CSI_NVM,
 532                         ctrl->ana_log_buf, ctrl->ana_log_size, 0);
 533         if (error) {
 534                 dev_warn(ctrl->device, "Failed to get ANA log: %d\n", error);
 535                 goto out_unlock;
 536         }
 537
 538         error = nvme_parse_ana_log(ctrl, &nr_change_groups,
 539                         nvme_update_ana_state);
 540         if (error)
 541                 goto out_unlock;
 542
 543         /*
 544          * In theory we should have an ANATT timer per group as they might enter
 545          * the change state at different times.  But that is a lot of overhead
 546          * just to protect against a target that keeps entering new changes
 547          * states while never finishing previous ones.  But we'll still
 548          * eventually time out once all groups are in change state, so this
 549          * isn't a big deal.
 550          *
 551          * We also double the ANATT value to provide some slack for transports
 552          * or AEN processing overhead.
 553          */
 554         if (nr_change_groups)
 555                 mod_timer(&ctrl->anatt_timer, ctrl->anatt * HZ * 2 + jiffies);
 556         else
 557                 del_timer_sync(&ctrl->anatt_timer);
 558 out_unlock:
 559         mutex_unlock(&ctrl->ana_lock);
 560         return error;
 561 }
 562
 563 static void nvme_ana_work(struct work_struct *work)
 564 {
 565         struct nvme_ctrl *ctrl = container_of(work, struct nvme_ctrl, ana_work);
 566
 567         if (ctrl->state != NVME_CTRL_LIVE)
 568                 return;
 569
 570         nvme_read_ana_log(ctrl);
 571 }
 572
 573 static void nvme_anatt_timeout(struct timer_list *t)
 574 {
 575         struct nvme_ctrl *ctrl = from_timer(ctrl, t, anatt_timer);
 576
 577         dev_info(ctrl->device, "ANATT timeout, resetting controller.\n");
 578         nvme_reset_ctrl(ctrl);
 579 }
 580
 581 void nvme_mpath_stop(struct nvme_ctrl *ctrl)
 582 {
 583         if (!nvme_ctrl_use_ana(ctrl))
 584                 return;
 585         del_timer_sync(&ctrl->anatt_timer);
 586         cancel_work_sync(&ctrl->ana_work);
 587 }
 588
 589 #define SUBSYS_ATTR_RW(_name, _mode, _show, _store)  \
 590         struct device_attribute subsys_attr_##_name =   \
 591                 __ATTR(_name, _mode, _show, _store)
 592
 593 static const char *nvme_iopolicy_names[] = {
 594         [NVME_IOPOLICY_NUMA]    = "numa",
 595         [NVME_IOPOLICY_RR]      = "round-robin",
 596 };
 597
 598 static ssize_t nvme_subsys_iopolicy_show(struct device *dev,
 599                 struct device_attribute *attr, char *buf)
 600 {
 601         struct nvme_subsystem *subsys =
 602                 container_of(dev, struct nvme_subsystem, dev);
 603
 604         return sprintf(buf, "%s\n",
 605                         nvme_iopolicy_names[READ_ONCE(subsys->iopolicy)]);
 606 }
 607
 608 static ssize_t nvme_subsys_iopolicy_store(struct device *dev,
 609                 struct device_attribute *attr, const char *buf, size_t count)
 610 {
 611         struct nvme_subsystem *subsys =
 612                 container_of(dev, struct nvme_subsystem, dev);
 613         int i;
 614
 615         for (i = 0; i < ARRAY_SIZE(nvme_iopolicy_names); i++) {
 616                 if (sysfs_streq(buf, nvme_iopolicy_names[i])) {
 617                         WRITE_ONCE(subsys->iopolicy, i);
 618                         return count;
 619                 }
 620         }
 621
 622         return -EINVAL;
 623 }
 624 SUBSYS_ATTR_RW(iopolicy, S_IRUGO | S_IWUSR,
 625                       nvme_subsys_iopolicy_show, nvme_subsys_iopolicy_store);
 626
 627 static ssize_t ana_grpid_show(struct device *dev, struct device_attribute *attr,
 628                 char *buf)
 629 {
 630         return sprintf(buf, "%d\n", nvme_get_ns_from_dev(dev)->ana_grpid);
 631 }
 632 DEVICE_ATTR_RO(ana_grpid);
 633
 634 static ssize_t ana_state_show(struct device *dev, struct device_attribute *attr,
 635                 char *buf)
 636 {
 637         struct nvme_ns *ns = nvme_get_ns_from_dev(dev);
 638
 639         return sprintf(buf, "%s\n", nvme_ana_state_names[ns->ana_state]);
 640 }
 641 DEVICE_ATTR_RO(ana_state);
 642
 643 static int nvme_lookup_ana_group_desc(struct nvme_ctrl *ctrl,
 644                 struct nvme_ana_group_desc *desc, void *data)
 645 {
 646         struct nvme_ana_group_desc *dst = data;
 647
 648         if (desc->grpid != dst->grpid)
 649                 return 0;
 650
 651         *dst = *desc;
 652         return -ENXIO; /* just break out of the loop */
 653 }
 654
 655 void nvme_mpath_add_disk(struct nvme_ns *ns, struct nvme_id_ns *id)
 656 {
 657         if (nvme_ctrl_use_ana(ns->ctrl)) {
 658                 struct nvme_ana_group_desc desc = {
 659                         .grpid = id->anagrpid,
 660                         .state = 0,
 661                 };
 662
 663                 mutex_lock(&ns->ctrl->ana_lock);
 664                 ns->ana_grpid = le32_to_cpu(id->anagrpid);
 665                 nvme_parse_ana_log(ns->ctrl, &desc, nvme_lookup_ana_group_desc);
 666                 mutex_unlock(&ns->ctrl->ana_lock);
 667                 if (desc.state) {
 668                         /* found the group desc: update */
 669                         nvme_update_ns_ana_state(&desc, ns);
 670                 }
 671         } else {
 672                 ns->ana_state = NVME_ANA_OPTIMIZED;
 673                 nvme_mpath_set_live(ns);
 674         }
 675
 676         if (bdi_cap_stable_pages_required(ns->queue->backing_dev_info)) {
 677                 struct gendisk *disk = ns->head->disk;
 678
 679                 if (disk)
 680                         disk->queue->backing_dev_info->capabilities |=
 681                                         BDI_CAP_STABLE_WRITES;
 682         }
 683 }
 684
 685 void nvme_mpath_remove_disk(struct nvme_ns_head *head)
 686 {
 687         if (!head->disk)
 688                 return;
 689         if (head->disk->flags & GENHD_FL_UP)
 690                 del_gendisk(head->disk);
 691         blk_set_queue_dying(head->disk->queue);
 692         /* make sure all pending bios are cleaned up */
 693         kblockd_schedule_work(&head->requeue_work);
 694         flush_work(&head->requeue_work);
 695         blk_cleanup_queue(head->disk->queue);
 696         if (!test_bit(NVME_NSHEAD_DISK_LIVE, &head->flags)) {
 697                 /*
 698                  * if device_add_disk wasn't called, prevent
 699                  * disk release to put a bogus reference on the
 700                  * request queue
 701                  */
 702                 head->disk->queue = NULL;
 703         }
 704         put_disk(head->disk);
 705 }
 706
 707 int nvme_mpath_init(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
 708 {
 709         int error;
 710
 711         /* check if multipath is enabled and we have the capability */
 712         if (!multipath || !ctrl->subsys ||
 713             !(ctrl->subsys->cmic & NVME_CTRL_CMIC_ANA))
 714                 return 0;
 715
 716         ctrl->anacap = id->anacap;
 717         ctrl->anatt = id->anatt;
 718         ctrl->nanagrpid = le32_to_cpu(id->nanagrpid);
 719         ctrl->anagrpmax = le32_to_cpu(id->anagrpmax);
 720
 721         mutex_init(&ctrl->ana_lock);
 722         timer_setup(&ctrl->anatt_timer, nvme_anatt_timeout, 0);
 723         ctrl->ana_log_size = sizeof(struct nvme_ana_rsp_hdr) +
 724                 ctrl->nanagrpid * sizeof(struct nvme_ana_group_desc);
 725         ctrl->ana_log_size += ctrl->max_namespaces * sizeof(__le32);
 726
 727         if (ctrl->ana_log_size > ctrl->max_hw_sectors << SECTOR_SHIFT) {
 728                 dev_err(ctrl->device,
 729                         "ANA log page size (%zd) larger than MDTS (%d).\n",
 730                         ctrl->ana_log_size,
 731                         ctrl->max_hw_sectors << SECTOR_SHIFT);
 732                 dev_err(ctrl->device, "disabling ANA support.\n");
 733                 return 0;
 734         }
 735
 736         INIT_WORK(&ctrl->ana_work, nvme_ana_work);
 737         kfree(ctrl->ana_log_buf);
 738         ctrl->ana_log_buf = kmalloc(ctrl->ana_log_size, GFP_KERNEL);
 739         if (!ctrl->ana_log_buf) {
 740                 error = -ENOMEM;
 741                 goto out;
 742         }
 743
 744         error = nvme_read_ana_log(ctrl);
 745         if (error)
 746                 goto out_free_ana_log_buf;
 747         return 0;
 748 out_free_ana_log_buf:
 749         kfree(ctrl->ana_log_buf);
 750         ctrl->ana_log_buf = NULL;
 751 out:
 752         return error;
 753 }
 754
 755 void nvme_mpath_uninit(struct nvme_ctrl *ctrl)
 756 {
 757         kfree(ctrl->ana_log_buf);
 758         ctrl->ana_log_buf = NULL;
 759 }
 760