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         down_read(&ctrl->namespaces_rwsem);
 139         list_for_each_entry(ns, &ctrl->namespaces, list) {
 140                 nvme_mpath_clear_current_path(ns);
 141                 kblockd_schedule_work(&ns->head->requeue_work);
 142         }
 143         up_read(&ctrl->namespaces_rwsem);
 144 }
 145
 146 static bool nvme_path_is_disabled(struct nvme_ns *ns)
 147 {
 148         /*
 149          * We don't treat NVME_CTRL_DELETING as a disabled path as I/O should
 150          * still be able to complete assuming that the controller is connected.
 151          * Otherwise it will fail immediately and return to the requeue list.
 152          */
 153         if (ns->ctrl->state != NVME_CTRL_LIVE &&
 154             ns->ctrl->state != NVME_CTRL_DELETING)
 155                 return true;
 156         if (test_bit(NVME_NS_ANA_PENDING, &ns->flags) ||
 157             test_bit(NVME_NS_REMOVING, &ns->flags))
 158                 return true;
 159         return false;
 160 }
 161
 162 static struct nvme_ns *__nvme_find_path(struct nvme_ns_head *head, int node)
 163 {
 164         int found_distance = INT_MAX, fallback_distance = INT_MAX, distance;
 165         struct nvme_ns *found = NULL, *fallback = NULL, *ns;
 166
 167         list_for_each_entry_rcu(ns, &head->list, siblings) {
 168                 if (nvme_path_is_disabled(ns))
 169                         continue;
 170
 171                 if (READ_ONCE(head->subsys->iopolicy) == NVME_IOPOLICY_NUMA)
 172                         distance = node_distance(node, ns->ctrl->numa_node);
 173                 else
 174                         distance = LOCAL_DISTANCE;
 175
 176                 switch (ns->ana_state) {
 177                 case NVME_ANA_OPTIMIZED:
 178                         if (distance < found_distance) {
 179                                 found_distance = distance;
 180                                 found = ns;
 181                         }
 182                         break;
 183                 case NVME_ANA_NONOPTIMIZED:
 184                         if (distance < fallback_distance) {
 185                                 fallback_distance = distance;
 186                                 fallback = ns;
 187                         }
 188                         break;
 189                 default:
 190                         break;
 191                 }
 192         }
 193
 194         if (!found)
 195                 found = fallback;
 196         if (found)
 197                 rcu_assign_pointer(head->current_path[node], found);
 198         return found;
 199 }
 200
 201 static struct nvme_ns *nvme_next_ns(struct nvme_ns_head *head,
 202                 struct nvme_ns *ns)
 203 {
 204         ns = list_next_or_null_rcu(&head->list, &ns->siblings, struct nvme_ns,
 205                         siblings);
 206         if (ns)
 207                 return ns;
 208         return list_first_or_null_rcu(&head->list, struct nvme_ns, siblings);
 209 }
 210
 211 static struct nvme_ns *nvme_round_robin_path(struct nvme_ns_head *head,
 212                 int node, struct nvme_ns *old)
 213 {
 214         struct nvme_ns *ns, *found = NULL;
 215
 216         if (list_is_singular(&head->list)) {
 217                 if (nvme_path_is_disabled(old))
 218                         return NULL;
 219                 return old;
 220         }
 221
 222         for (ns = nvme_next_ns(head, old);
 223              ns && ns != old;
 224              ns = nvme_next_ns(head, ns)) {
 225                 if (nvme_path_is_disabled(ns))
 226                         continue;
 227
 228                 if (ns->ana_state == NVME_ANA_OPTIMIZED) {
 229                         found = ns;
 230                         goto out;
 231                 }
 232                 if (ns->ana_state == NVME_ANA_NONOPTIMIZED)
 233                         found = ns;
 234         }
 235
 236         /*
 237          * The loop above skips the current path for round-robin semantics.
 238          * Fall back to the current path if either:
 239          *  - no other optimized path found and current is optimized,
 240          *  - no other usable path found and current is usable.
 241          */
 242         if (!nvme_path_is_disabled(old) &&
 243             (old->ana_state == NVME_ANA_OPTIMIZED ||
 244              (!found && old->ana_state == NVME_ANA_NONOPTIMIZED)))
 245                 return old;
 246
 247         if (!found)
 248                 return NULL;
 249 out:
 250         rcu_assign_pointer(head->current_path[node], found);
 251         return found;
 252 }
 253
 254 static inline bool nvme_path_is_optimized(struct nvme_ns *ns)
 255 {
 256         return ns->ctrl->state == NVME_CTRL_LIVE &&
 257                 ns->ana_state == NVME_ANA_OPTIMIZED;
 258 }
 259
 260 inline struct nvme_ns *nvme_find_path(struct nvme_ns_head *head)
 261 {
 262         int node = numa_node_id();
 263         struct nvme_ns *ns;
 264
 265         ns = srcu_dereference(head->current_path[node], &head->srcu);
 266         if (unlikely(!ns))
 267                 return __nvme_find_path(head, node);
 268
 269         if (READ_ONCE(head->subsys->iopolicy) == NVME_IOPOLICY_RR)
 270                 return nvme_round_robin_path(head, node, ns);
 271         if (unlikely(!nvme_path_is_optimized(ns)))
 272                 return __nvme_find_path(head, node);
 273         return ns;
 274 }
 275
 276 static bool nvme_available_path(struct nvme_ns_head *head)
 277 {
 278         struct nvme_ns *ns;
 279
 280         list_for_each_entry_rcu(ns, &head->list, siblings) {
 281                 switch (ns->ctrl->state) {
 282                 case NVME_CTRL_LIVE:
 283                 case NVME_CTRL_RESETTING:
 284                 case NVME_CTRL_CONNECTING:
 285                         /* fallthru */
 286                         return true;
 287                 default:
 288                         break;
 289                 }
 290         }
 291         return false;
 292 }
 293
 294 blk_qc_t nvme_ns_head_submit_bio(struct bio *bio)
 295 {
 296         struct nvme_ns_head *head = bio->bi_disk->private_data;
 297         struct device *dev = disk_to_dev(head->disk);
 298         struct nvme_ns *ns;
 299         blk_qc_t ret = BLK_QC_T_NONE;
 300         int srcu_idx;
 301
 302         /*
 303          * The namespace might be going away and the bio might be moved to a
 304          * different queue via blk_steal_bios(), so we need to use the bio_split
 305          * pool from the original queue to allocate the bvecs from.
 306          */
 307         blk_queue_split(&bio);
 308
 309         srcu_idx = srcu_read_lock(&head->srcu);
 310         ns = nvme_find_path(head);
 311         if (likely(ns)) {
 312                 bio->bi_disk = ns->disk;
 313                 bio->bi_opf |= REQ_NVME_MPATH;
 314                 trace_block_bio_remap(bio->bi_disk->queue, bio,
 315                                       disk_devt(ns->head->disk),
 316                                       bio->bi_iter.bi_sector);
 317                 ret = submit_bio_noacct(bio);
 318         } else if (nvme_available_path(head)) {
 319                 dev_warn_ratelimited(dev, "no usable path - requeuing I/O\n");
 320
 321                 spin_lock_irq(&head->requeue_lock);
 322                 bio_list_add(&head->requeue_list, bio);
 323                 spin_unlock_irq(&head->requeue_lock);
 324         } else {
 325                 dev_warn_ratelimited(dev, "no available path - failing I/O\n");
 326
 327                 bio->bi_status = BLK_STS_IOERR;
 328                 bio_endio(bio);
 329         }
 330
 331         srcu_read_unlock(&head->srcu, srcu_idx);
 332         return ret;
 333 }
 334
 335 static void nvme_requeue_work(struct work_struct *work)
 336 {
 337         struct nvme_ns_head *head =
 338                 container_of(work, struct nvme_ns_head, requeue_work);
 339         struct bio *bio, *next;
 340
 341         spin_lock_irq(&head->requeue_lock);
 342         next = bio_list_get(&head->requeue_list);
 343         spin_unlock_irq(&head->requeue_lock);
 344
 345         while ((bio = next) != NULL) {
 346                 next = bio->bi_next;
 347                 bio->bi_next = NULL;
 348
 349                 /*
 350                  * Reset disk to the mpath node and resubmit to select a new
 351                  * path.
 352                  */
 353                 bio->bi_disk = head->disk;
 354                 submit_bio_noacct(bio);
 355         }
 356 }
 357
 358 int nvme_mpath_alloc_disk(struct nvme_ctrl *ctrl, struct nvme_ns_head *head)
 359 {
 360         struct request_queue *q;
 361         bool vwc = false;
 362
 363         mutex_init(&head->lock);
 364         bio_list_init(&head->requeue_list);
 365         spin_lock_init(&head->requeue_lock);
 366         INIT_WORK(&head->requeue_work, nvme_requeue_work);
 367
 368         /*
 369          * Add a multipath node if the subsystems supports multiple controllers.
 370          * We also do this for private namespaces as the namespace sharing data could
 371          * change after a rescan.
 372          */
 373         if (!(ctrl->subsys->cmic & NVME_CTRL_CMIC_MULTI_CTRL) || !multipath)
 374                 return 0;
 375
 376         q = blk_alloc_queue(ctrl->numa_node);
 377         if (!q)
 378                 goto out;
 379         blk_queue_flag_set(QUEUE_FLAG_NONROT, q);
 380         /* set to a default value for 512 until disk is validated */
 381         blk_queue_logical_block_size(q, 512);
 382         blk_set_stacking_limits(&q->limits);
 383
 384         /* we need to propagate up the VMC settings */
 385         if (ctrl->vwc & NVME_CTRL_VWC_PRESENT)
 386                 vwc = true;
 387         blk_queue_write_cache(q, vwc, vwc);
 388
 389         head->disk = alloc_disk(0);
 390         if (!head->disk)
 391                 goto out_cleanup_queue;
 392         head->disk->fops = &nvme_ns_head_ops;
 393         head->disk->private_data = head;
 394         head->disk->queue = q;
 395         head->disk->flags = GENHD_FL_EXT_DEVT;
 396         sprintf(head->disk->disk_name, "nvme%dn%d",
 397                         ctrl->subsys->instance, head->instance);
 398         return 0;
 399
 400 out_cleanup_queue:
 401         blk_cleanup_queue(q);
 402 out:
 403         return -ENOMEM;
 404 }
 405
 406 static void nvme_mpath_set_live(struct nvme_ns *ns)
 407 {
 408         struct nvme_ns_head *head = ns->head;
 409
 410         if (!head->disk)
 411                 return;
 412
 413         if (!test_and_set_bit(NVME_NSHEAD_DISK_LIVE, &head->flags))
 414                 device_add_disk(&head->subsys->dev, head->disk,
 415                                 nvme_ns_id_attr_groups);
 416
 417         mutex_lock(&head->lock);
 418         if (nvme_path_is_optimized(ns)) {
 419                 int node, srcu_idx;
 420
 421                 srcu_idx = srcu_read_lock(&head->srcu);
 422                 for_each_node(node)
 423                         __nvme_find_path(head, node);
 424                 srcu_read_unlock(&head->srcu, srcu_idx);
 425         }
 426         mutex_unlock(&head->lock);
 427
 428         synchronize_srcu(&head->srcu);
 429         kblockd_schedule_work(&head->requeue_work);
 430 }
 431
 432 static int nvme_parse_ana_log(struct nvme_ctrl *ctrl, void *data,
 433                 int (*cb)(struct nvme_ctrl *ctrl, struct nvme_ana_group_desc *,
 434                         void *))
 435 {
 436         void *base = ctrl->ana_log_buf;
 437         size_t offset = sizeof(struct nvme_ana_rsp_hdr);
 438         int error, i;
 439
 440         lockdep_assert_held(&ctrl->ana_lock);
 441
 442         for (i = 0; i < le16_to_cpu(ctrl->ana_log_buf->ngrps); i++) {
 443                 struct nvme_ana_group_desc *desc = base + offset;
 444                 u32 nr_nsids;
 445                 size_t nsid_buf_size;
 446
 447                 if (WARN_ON_ONCE(offset > ctrl->ana_log_size - sizeof(*desc)))
 448                         return -EINVAL;
 449
 450                 nr_nsids = le32_to_cpu(desc->nnsids);
 451                 nsid_buf_size = nr_nsids * sizeof(__le32);
 452
 453                 if (WARN_ON_ONCE(desc->grpid == 0))
 454                         return -EINVAL;
 455                 if (WARN_ON_ONCE(le32_to_cpu(desc->grpid) > ctrl->anagrpmax))
 456                         return -EINVAL;
 457                 if (WARN_ON_ONCE(desc->state == 0))
 458                         return -EINVAL;
 459                 if (WARN_ON_ONCE(desc->state > NVME_ANA_CHANGE))
 460                         return -EINVAL;
 461
 462                 offset += sizeof(*desc);
 463                 if (WARN_ON_ONCE(offset > ctrl->ana_log_size - nsid_buf_size))
 464                         return -EINVAL;
 465
 466                 error = cb(ctrl, desc, data);
 467                 if (error)
 468                         return error;
 469
 470                 offset += nsid_buf_size;
 471         }
 472
 473         return 0;
 474 }
 475
 476 static inline bool nvme_state_is_live(enum nvme_ana_state state)
 477 {
 478         return state == NVME_ANA_OPTIMIZED || state == NVME_ANA_NONOPTIMIZED;
 479 }
 480
 481 static void nvme_update_ns_ana_state(struct nvme_ana_group_desc *desc,
 482                 struct nvme_ns *ns)
 483 {
 484         ns->ana_grpid = le32_to_cpu(desc->grpid);
 485         ns->ana_state = desc->state;
 486         clear_bit(NVME_NS_ANA_PENDING, &ns->flags);
 487         /*
 488          * nvme_mpath_set_live() will trigger I/O to the multipath path device
 489          * and in turn to this path device.  However we cannot accept this I/O
 490          * if the controller is not live.  This may deadlock if called from
 491          * nvme_mpath_init_identify() and the ctrl will never complete
 492          * initialization, preventing I/O from completing.  For this case we
 493          * will reprocess the ANA log page in nvme_mpath_update() once the
 494          * controller is ready.
 495          */
 496         if (nvme_state_is_live(ns->ana_state) &&
 497             ns->ctrl->state == NVME_CTRL_LIVE)
 498                 nvme_mpath_set_live(ns);
 499 }
 500
 501 static int nvme_update_ana_state(struct nvme_ctrl *ctrl,
 502                 struct nvme_ana_group_desc *desc, void *data)
 503 {
 504         u32 nr_nsids = le32_to_cpu(desc->nnsids), n = 0;
 505         unsigned *nr_change_groups = data;
 506         struct nvme_ns *ns;
 507
 508         dev_dbg(ctrl->device, "ANA group %d: %s.\n",
 509                         le32_to_cpu(desc->grpid),
 510                         nvme_ana_state_names[desc->state]);
 511
 512         if (desc->state == NVME_ANA_CHANGE)
 513                 (*nr_change_groups)++;
 514
 515         if (!nr_nsids)
 516                 return 0;
 517
 518         down_read(&ctrl->namespaces_rwsem);
 519         list_for_each_entry(ns, &ctrl->namespaces, list) {
 520                 unsigned nsid;
 521 again:
 522                 nsid = le32_to_cpu(desc->nsids[n]);
 523                 if (ns->head->ns_id < nsid)
 524                         continue;
 525                 if (ns->head->ns_id == nsid)
 526                         nvme_update_ns_ana_state(desc, ns);
 527                 if (++n == nr_nsids)
 528                         break;
 529                 if (ns->head->ns_id > nsid)
 530                         goto again;
 531         }
 532         up_read(&ctrl->namespaces_rwsem);
 533         return 0;
 534 }
 535
 536 static int nvme_read_ana_log(struct nvme_ctrl *ctrl)
 537 {
 538         u32 nr_change_groups = 0;
 539         int error;
 540
 541         mutex_lock(&ctrl->ana_lock);
 542         error = nvme_get_log(ctrl, NVME_NSID_ALL, NVME_LOG_ANA, 0, NVME_CSI_NVM,
 543                         ctrl->ana_log_buf, ctrl->ana_log_size, 0);
 544         if (error) {
 545                 dev_warn(ctrl->device, "Failed to get ANA log: %d\n", error);
 546                 goto out_unlock;
 547         }
 548
 549         error = nvme_parse_ana_log(ctrl, &nr_change_groups,
 550                         nvme_update_ana_state);
 551         if (error)
 552                 goto out_unlock;
 553
 554         /*
 555          * In theory we should have an ANATT timer per group as they might enter
 556          * the change state at different times.  But that is a lot of overhead
 557          * just to protect against a target that keeps entering new changes
 558          * states while never finishing previous ones.  But we'll still
 559          * eventually time out once all groups are in change state, so this
 560          * isn't a big deal.
 561          *
 562          * We also double the ANATT value to provide some slack for transports
 563          * or AEN processing overhead.
 564          */
 565         if (nr_change_groups)
 566                 mod_timer(&ctrl->anatt_timer, ctrl->anatt * HZ * 2 + jiffies);
 567         else
 568                 del_timer_sync(&ctrl->anatt_timer);
 569 out_unlock:
 570         mutex_unlock(&ctrl->ana_lock);
 571         return error;
 572 }
 573
 574 static void nvme_ana_work(struct work_struct *work)
 575 {
 576         struct nvme_ctrl *ctrl = container_of(work, struct nvme_ctrl, ana_work);
 577
 578         if (ctrl->state != NVME_CTRL_LIVE)
 579                 return;
 580
 581         nvme_read_ana_log(ctrl);
 582 }
 583
 584 void nvme_mpath_update(struct nvme_ctrl *ctrl)
 585 {
 586         u32 nr_change_groups = 0;
 587
 588         if (!ctrl->ana_log_buf)
 589                 return;
 590
 591         mutex_lock(&ctrl->ana_lock);
 592         nvme_parse_ana_log(ctrl, &nr_change_groups, nvme_update_ana_state);
 593         mutex_unlock(&ctrl->ana_lock);
 594 }
 595
 596 static void nvme_anatt_timeout(struct timer_list *t)
 597 {
 598         struct nvme_ctrl *ctrl = from_timer(ctrl, t, anatt_timer);
 599
 600         dev_info(ctrl->device, "ANATT timeout, resetting controller.\n");
 601         nvme_reset_ctrl(ctrl);
 602 }
 603
 604 void nvme_mpath_stop(struct nvme_ctrl *ctrl)
 605 {
 606         if (!nvme_ctrl_use_ana(ctrl))
 607                 return;
 608         del_timer_sync(&ctrl->anatt_timer);
 609         cancel_work_sync(&ctrl->ana_work);
 610 }
 611
 612 #define SUBSYS_ATTR_RW(_name, _mode, _show, _store)  \
 613         struct device_attribute subsys_attr_##_name =   \
 614                 __ATTR(_name, _mode, _show, _store)
 615
 616 static const char *nvme_iopolicy_names[] = {
 617         [NVME_IOPOLICY_NUMA]    = "numa",
 618         [NVME_IOPOLICY_RR]      = "round-robin",
 619 };
 620
 621 static ssize_t nvme_subsys_iopolicy_show(struct device *dev,
 622                 struct device_attribute *attr, char *buf)
 623 {
 624         struct nvme_subsystem *subsys =
 625                 container_of(dev, struct nvme_subsystem, dev);
 626
 627         return sysfs_emit(buf, "%s\n",
 628                           nvme_iopolicy_names[READ_ONCE(subsys->iopolicy)]);
 629 }
 630
 631 static ssize_t nvme_subsys_iopolicy_store(struct device *dev,
 632                 struct device_attribute *attr, const char *buf, size_t count)
 633 {
 634         struct nvme_subsystem *subsys =
 635                 container_of(dev, struct nvme_subsystem, dev);
 636         int i;
 637
 638         for (i = 0; i < ARRAY_SIZE(nvme_iopolicy_names); i++) {
 639                 if (sysfs_streq(buf, nvme_iopolicy_names[i])) {
 640                         WRITE_ONCE(subsys->iopolicy, i);
 641                         return count;
 642                 }
 643         }
 644
 645         return -EINVAL;
 646 }
 647 SUBSYS_ATTR_RW(iopolicy, S_IRUGO | S_IWUSR,
 648                       nvme_subsys_iopolicy_show, nvme_subsys_iopolicy_store);
 649
 650 static ssize_t ana_grpid_show(struct device *dev, struct device_attribute *attr,
 651                 char *buf)
 652 {
 653         return sysfs_emit(buf, "%d\n", nvme_get_ns_from_dev(dev)->ana_grpid);
 654 }
 655 DEVICE_ATTR_RO(ana_grpid);
 656
 657 static ssize_t ana_state_show(struct device *dev, struct device_attribute *attr,
 658                 char *buf)
 659 {
 660         struct nvme_ns *ns = nvme_get_ns_from_dev(dev);
 661
 662         return sysfs_emit(buf, "%s\n", nvme_ana_state_names[ns->ana_state]);
 663 }
 664 DEVICE_ATTR_RO(ana_state);
 665
 666 static int nvme_lookup_ana_group_desc(struct nvme_ctrl *ctrl,
 667                 struct nvme_ana_group_desc *desc, void *data)
 668 {
 669         struct nvme_ana_group_desc *dst = data;
 670
 671         if (desc->grpid != dst->grpid)
 672                 return 0;
 673
 674         *dst = *desc;
 675         return -ENXIO; /* just break out of the loop */
 676 }
 677
 678 void nvme_mpath_add_disk(struct nvme_ns *ns, struct nvme_id_ns *id)
 679 {
 680         if (nvme_ctrl_use_ana(ns->ctrl)) {
 681                 struct nvme_ana_group_desc desc = {
 682                         .grpid = id->anagrpid,
 683                         .state = 0,
 684                 };
 685
 686                 mutex_lock(&ns->ctrl->ana_lock);
 687                 ns->ana_grpid = le32_to_cpu(id->anagrpid);
 688                 nvme_parse_ana_log(ns->ctrl, &desc, nvme_lookup_ana_group_desc);
 689                 mutex_unlock(&ns->ctrl->ana_lock);
 690                 if (desc.state) {
 691                         /* found the group desc: update */
 692                         nvme_update_ns_ana_state(&desc, ns);
 693                 } else {
 694                         /* group desc not found: trigger a re-read */
 695                         set_bit(NVME_NS_ANA_PENDING, &ns->flags);
 696                         queue_work(nvme_wq, &ns->ctrl->ana_work);
 697                 }
 698         } else {
 699                 ns->ana_state = NVME_ANA_OPTIMIZED;
 700                 nvme_mpath_set_live(ns);
 701         }
 702
 703         if (blk_queue_stable_writes(ns->queue) && ns->head->disk)
 704                 blk_queue_flag_set(QUEUE_FLAG_STABLE_WRITES,
 705                                    ns->head->disk->queue);
 706 #ifdef CONFIG_BLK_DEV_ZONED
 707         if (blk_queue_is_zoned(ns->queue) && ns->head->disk)
 708                 ns->head->disk->queue->nr_zones = ns->queue->nr_zones;
 709 #endif
 710 }
 711
 712 void nvme_mpath_remove_disk(struct nvme_ns_head *head)
 713 {
 714         if (!head->disk)
 715                 return;
 716         if (head->disk->flags & GENHD_FL_UP)
 717                 del_gendisk(head->disk);
 718         blk_set_queue_dying(head->disk->queue);
 719         /* make sure all pending bios are cleaned up */
 720         kblockd_schedule_work(&head->requeue_work);
 721         flush_work(&head->requeue_work);
 722         blk_cleanup_queue(head->disk->queue);
 723         if (!test_bit(NVME_NSHEAD_DISK_LIVE, &head->flags)) {
 724                 /*
 725                  * if device_add_disk wasn't called, prevent
 726                  * disk release to put a bogus reference on the
 727                  * request queue
 728                  */
 729                 head->disk->queue = NULL;
 730         }
 731         put_disk(head->disk);
 732 }
 733
 734 void nvme_mpath_init_ctrl(struct nvme_ctrl *ctrl)
 735 {
 736         mutex_init(&ctrl->ana_lock);
 737         timer_setup(&ctrl->anatt_timer, nvme_anatt_timeout, 0);
 738         INIT_WORK(&ctrl->ana_work, nvme_ana_work);
 739 }
 740
 741 int nvme_mpath_init_identify(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
 742 {
 743         size_t max_transfer_size = ctrl->max_hw_sectors << SECTOR_SHIFT;
 744         size_t ana_log_size;
 745         int error = 0;
 746
 747         /* check if multipath is enabled and we have the capability */
 748         if (!multipath || !ctrl->subsys ||
 749             !(ctrl->subsys->cmic & NVME_CTRL_CMIC_ANA))
 750                 return 0;
 751
 752         ctrl->anacap = id->anacap;
 753         ctrl->anatt = id->anatt;
 754         ctrl->nanagrpid = le32_to_cpu(id->nanagrpid);
 755         ctrl->anagrpmax = le32_to_cpu(id->anagrpmax);
 756
 757         ana_log_size = sizeof(struct nvme_ana_rsp_hdr) +
 758                 ctrl->nanagrpid * sizeof(struct nvme_ana_group_desc) +
 759                 ctrl->max_namespaces * sizeof(__le32);
 760         if (ana_log_size > max_transfer_size) {
 761                 dev_err(ctrl->device,
 762                         "ANA log page size (%zd) larger than MDTS (%zd).\n",
 763                         ana_log_size, max_transfer_size);
 764                 dev_err(ctrl->device, "disabling ANA support.\n");
 765                 goto out_uninit;
 766         }
 767         if (ana_log_size > ctrl->ana_log_size) {
 768                 nvme_mpath_stop(ctrl);
 769                 kfree(ctrl->ana_log_buf);
 770                 ctrl->ana_log_buf = kmalloc(ana_log_size, GFP_KERNEL);
 771                 if (!ctrl->ana_log_buf)
 772                         return -ENOMEM;
 773         }
 774         ctrl->ana_log_size = ana_log_size;
 775         error = nvme_read_ana_log(ctrl);
 776         if (error)
 777                 goto out_uninit;
 778         return 0;
 779
 780 out_uninit:
 781         nvme_mpath_uninit(ctrl);
 782         return error;
 783 }
 784
 785 void nvme_mpath_uninit(struct nvme_ctrl *ctrl)
 786 {
 787         kfree(ctrl->ana_log_buf);
 788         ctrl->ana_log_buf = NULL;
 789 }
 790