block/blk-sysfs.c

   1 /*
   2  * Functions related to sysfs handling
   3  */
   4 #include <linux/kernel.h>
   5 #include <linux/slab.h>
   6 #include <linux/module.h>
   7 #include <linux/bio.h>
   8 #include <linux/blkdev.h>
   9 #include <linux/backing-dev.h>
  10 #include <linux/blktrace_api.h>
  11 #include <linux/blk-mq.h>
  12 #include <linux/blk-cgroup.h>
  13
  14 #include "blk.h"
  15 #include "blk-mq.h"
  16
  17 struct queue_sysfs_entry {
  18         struct attribute attr;
  19         ssize_t (*show)(struct request_queue *, char *);
  20         ssize_t (*store)(struct request_queue *, const char *, size_t);
  21 };
  22
  23 static ssize_t
  24 queue_var_show(unsigned long var, char *page)
  25 {
  26         return sprintf(page, "%lu\n", var);
  27 }
  28
  29 static ssize_t
  30 queue_var_store(unsigned long *var, const char *page, size_t count)
  31 {
  32         int err;
  33         unsigned long v;
  34
  35         err = kstrtoul(page, 10, &v);
  36         if (err || v > UINT_MAX)
  37                 return -EINVAL;
  38
  39         *var = v;
  40
  41         return count;
  42 }
  43
  44 static ssize_t queue_requests_show(struct request_queue *q, char *page)
  45 {
  46         return queue_var_show(q->nr_requests, (page));
  47 }
  48
  49 static ssize_t
  50 queue_requests_store(struct request_queue *q, const char *page, size_t count)
  51 {
  52         unsigned long nr;
  53         int ret, err;
  54
  55         if (!q->request_fn && !q->mq_ops)
  56                 return -EINVAL;
  57
  58         ret = queue_var_store(&nr, page, count);
  59         if (ret < 0)
  60                 return ret;
  61
  62         if (nr < BLKDEV_MIN_RQ)
  63                 nr = BLKDEV_MIN_RQ;
  64
  65         if (q->request_fn)
  66                 err = blk_update_nr_requests(q, nr);
  67         else
  68                 err = blk_mq_update_nr_requests(q, nr);
  69
  70         if (err)
  71                 return err;
  72
  73         return ret;
  74 }
  75
  76 static ssize_t queue_ra_show(struct request_queue *q, char *page)
  77 {
  78         unsigned long ra_kb = q->backing_dev_info.ra_pages <<
  79                                         (PAGE_CACHE_SHIFT - 10);
  80
  81         return queue_var_show(ra_kb, (page));
  82 }
  83
  84 static ssize_t
  85 queue_ra_store(struct request_queue *q, const char *page, size_t count)
  86 {
  87         unsigned long ra_kb;
  88         ssize_t ret = queue_var_store(&ra_kb, page, count);
  89
  90         if (ret < 0)
  91                 return ret;
  92
  93         q->backing_dev_info.ra_pages = ra_kb >> (PAGE_CACHE_SHIFT - 10);
  94
  95         return ret;
  96 }
  97
  98 static ssize_t queue_max_sectors_show(struct request_queue *q, char *page)
  99 {
 100         int max_sectors_kb = queue_max_sectors(q) >> 1;
 101
 102         return queue_var_show(max_sectors_kb, (page));
 103 }
 104
 105 static ssize_t queue_max_segments_show(struct request_queue *q, char *page)
 106 {
 107         return queue_var_show(queue_max_segments(q), (page));
 108 }
 109
 110 static ssize_t queue_max_integrity_segments_show(struct request_queue *q, char *page)
 111 {
 112         return queue_var_show(q->limits.max_integrity_segments, (page));
 113 }
 114
 115 static ssize_t queue_max_segment_size_show(struct request_queue *q, char *page)
 116 {
 117         if (blk_queue_cluster(q))
 118                 return queue_var_show(queue_max_segment_size(q), (page));
 119
 120         return queue_var_show(PAGE_CACHE_SIZE, (page));
 121 }
 122
 123 static ssize_t queue_logical_block_size_show(struct request_queue *q, char *page)
 124 {
 125         return queue_var_show(queue_logical_block_size(q), page);
 126 }
 127
 128 static ssize_t queue_physical_block_size_show(struct request_queue *q, char *page)
 129 {
 130         return queue_var_show(queue_physical_block_size(q), page);
 131 }
 132
 133 static ssize_t queue_io_min_show(struct request_queue *q, char *page)
 134 {
 135         return queue_var_show(queue_io_min(q), page);
 136 }
 137
 138 static ssize_t queue_io_opt_show(struct request_queue *q, char *page)
 139 {
 140         return queue_var_show(queue_io_opt(q), page);
 141 }
 142
 143 static ssize_t queue_discard_granularity_show(struct request_queue *q, char *page)
 144 {
 145         return queue_var_show(q->limits.discard_granularity, page);
 146 }
 147
 148 static ssize_t queue_discard_max_hw_show(struct request_queue *q, char *page)
 149 {
 150         unsigned long long val;
 151
 152         val = q->limits.max_hw_discard_sectors << 9;
 153         return sprintf(page, "%llu\n", val);
 154 }
 155
 156 static ssize_t queue_discard_max_show(struct request_queue *q, char *page)
 157 {
 158         return sprintf(page, "%llu\n",
 159                        (unsigned long long)q->limits.max_discard_sectors << 9);
 160 }
 161
 162 static ssize_t queue_discard_max_store(struct request_queue *q,
 163                                        const char *page, size_t count)
 164 {
 165         unsigned long max_discard;
 166         ssize_t ret = queue_var_store(&max_discard, page, count);
 167
 168         if (ret < 0)
 169                 return ret;
 170
 171         if (max_discard & (q->limits.discard_granularity - 1))
 172                 return -EINVAL;
 173
 174         max_discard >>= 9;
 175         if (max_discard > UINT_MAX)
 176                 return -EINVAL;
 177
 178         if (max_discard > q->limits.max_hw_discard_sectors)
 179                 max_discard = q->limits.max_hw_discard_sectors;
 180
 181         q->limits.max_discard_sectors = max_discard;
 182         return ret;
 183 }
 184
 185 static ssize_t queue_discard_zeroes_data_show(struct request_queue *q, char *page)
 186 {
 187         return queue_var_show(queue_discard_zeroes_data(q), page);
 188 }
 189
 190 static ssize_t queue_write_same_max_show(struct request_queue *q, char *page)
 191 {
 192         return sprintf(page, "%llu\n",
 193                 (unsigned long long)q->limits.max_write_same_sectors << 9);
 194 }
 195
 196
 197 static ssize_t
 198 queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
 199 {
 200         unsigned long max_sectors_kb,
 201                 max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1,
 202                         page_kb = 1 << (PAGE_CACHE_SHIFT - 10);
 203         ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
 204
 205         if (ret < 0)
 206                 return ret;
 207
 208         if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
 209                 return -EINVAL;
 210
 211         spin_lock_irq(q->queue_lock);
 212         q->limits.max_sectors = max_sectors_kb << 1;
 213         spin_unlock_irq(q->queue_lock);
 214
 215         return ret;
 216 }
 217
 218 static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
 219 {
 220         int max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1;
 221
 222         return queue_var_show(max_hw_sectors_kb, (page));
 223 }
 224
 225 #define QUEUE_SYSFS_BIT_FNS(name, flag, neg)                            \
 226 static ssize_t                                                          \
 227 queue_show_##name(struct request_queue *q, char *page)                  \
 228 {                                                                       \
 229         int bit;                                                        \
 230         bit = test_bit(QUEUE_FLAG_##flag, &q->queue_flags);             \
 231         return queue_var_show(neg ? !bit : bit, page);                  \
 232 }                                                                       \
 233 static ssize_t                                                          \
 234 queue_store_##name(struct request_queue *q, const char *page, size_t count) \
 235 {                                                                       \
 236         unsigned long val;                                              \
 237         ssize_t ret;                                                    \
 238         ret = queue_var_store(&val, page, count);                       \
 239         if (ret < 0)                                                    \
 240                  return ret;                                            \
 241         if (neg)                                                        \
 242                 val = !val;                                             \
 243                                                                         \
 244         spin_lock_irq(q->queue_lock);                                   \
 245         if (val)                                                        \
 246                 queue_flag_set(QUEUE_FLAG_##flag, q);                   \
 247         else                                                            \
 248                 queue_flag_clear(QUEUE_FLAG_##flag, q);                 \
 249         spin_unlock_irq(q->queue_lock);                                 \
 250         return ret;                                                     \
 251 }
 252
 253 QUEUE_SYSFS_BIT_FNS(nonrot, NONROT, 1);
 254 QUEUE_SYSFS_BIT_FNS(random, ADD_RANDOM, 0);
 255 QUEUE_SYSFS_BIT_FNS(iostats, IO_STAT, 0);
 256 #undef QUEUE_SYSFS_BIT_FNS
 257
 258 static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
 259 {
 260         return queue_var_show((blk_queue_nomerges(q) << 1) |
 261                                blk_queue_noxmerges(q), page);
 262 }
 263
 264 static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
 265                                     size_t count)
 266 {
 267         unsigned long nm;
 268         ssize_t ret = queue_var_store(&nm, page, count);
 269
 270         if (ret < 0)
 271                 return ret;
 272
 273         spin_lock_irq(q->queue_lock);
 274         queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
 275         queue_flag_clear(QUEUE_FLAG_NOXMERGES, q);
 276         if (nm == 2)
 277                 queue_flag_set(QUEUE_FLAG_NOMERGES, q);
 278         else if (nm)
 279                 queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
 280         spin_unlock_irq(q->queue_lock);
 281
 282         return ret;
 283 }
 284
 285 static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
 286 {
 287         bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);
 288         bool force = test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags);
 289
 290         return queue_var_show(set << force, page);
 291 }
 292
 293 static ssize_t
 294 queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
 295 {
 296         ssize_t ret = -EINVAL;
 297 #ifdef CONFIG_SMP
 298         unsigned long val;
 299
 300         ret = queue_var_store(&val, page, count);
 301         if (ret < 0)
 302                 return ret;
 303
 304         spin_lock_irq(q->queue_lock);
 305         if (val == 2) {
 306                 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 307                 queue_flag_set(QUEUE_FLAG_SAME_FORCE, q);
 308         } else if (val == 1) {
 309                 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
 310                 queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
 311         } else if (val == 0) {
 312                 queue_flag_clear(QUEUE_FLAG_SAME_COMP, q);
 313                 queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
 314         }
 315         spin_unlock_irq(q->queue_lock);
 316 #endif
 317         return ret;
 318 }
 319
 320 static struct queue_sysfs_entry queue_requests_entry = {
 321         .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
 322         .show = queue_requests_show,
 323         .store = queue_requests_store,
 324 };
 325
 326 static struct queue_sysfs_entry queue_ra_entry = {
 327         .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
 328         .show = queue_ra_show,
 329         .store = queue_ra_store,
 330 };
 331
 332 static struct queue_sysfs_entry queue_max_sectors_entry = {
 333         .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
 334         .show = queue_max_sectors_show,
 335         .store = queue_max_sectors_store,
 336 };
 337
 338 static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
 339         .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
 340         .show = queue_max_hw_sectors_show,
 341 };
 342
 343 static struct queue_sysfs_entry queue_max_segments_entry = {
 344         .attr = {.name = "max_segments", .mode = S_IRUGO },
 345         .show = queue_max_segments_show,
 346 };
 347
 348 static struct queue_sysfs_entry queue_max_integrity_segments_entry = {
 349         .attr = {.name = "max_integrity_segments", .mode = S_IRUGO },
 350         .show = queue_max_integrity_segments_show,
 351 };
 352
 353 static struct queue_sysfs_entry queue_max_segment_size_entry = {
 354         .attr = {.name = "max_segment_size", .mode = S_IRUGO },
 355         .show = queue_max_segment_size_show,
 356 };
 357
 358 static struct queue_sysfs_entry queue_iosched_entry = {
 359         .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
 360         .show = elv_iosched_show,
 361         .store = elv_iosched_store,
 362 };
 363
 364 static struct queue_sysfs_entry queue_hw_sector_size_entry = {
 365         .attr = {.name = "hw_sector_size", .mode = S_IRUGO },
 366         .show = queue_logical_block_size_show,
 367 };
 368
 369 static struct queue_sysfs_entry queue_logical_block_size_entry = {
 370         .attr = {.name = "logical_block_size", .mode = S_IRUGO },
 371         .show = queue_logical_block_size_show,
 372 };
 373
 374 static struct queue_sysfs_entry queue_physical_block_size_entry = {
 375         .attr = {.name = "physical_block_size", .mode = S_IRUGO },
 376         .show = queue_physical_block_size_show,
 377 };
 378
 379 static struct queue_sysfs_entry queue_io_min_entry = {
 380         .attr = {.name = "minimum_io_size", .mode = S_IRUGO },
 381         .show = queue_io_min_show,
 382 };
 383
 384 static struct queue_sysfs_entry queue_io_opt_entry = {
 385         .attr = {.name = "optimal_io_size", .mode = S_IRUGO },
 386         .show = queue_io_opt_show,
 387 };
 388
 389 static struct queue_sysfs_entry queue_discard_granularity_entry = {
 390         .attr = {.name = "discard_granularity", .mode = S_IRUGO },
 391         .show = queue_discard_granularity_show,
 392 };
 393
 394 static struct queue_sysfs_entry queue_discard_max_hw_entry = {
 395         .attr = {.name = "discard_max_hw_bytes", .mode = S_IRUGO },
 396         .show = queue_discard_max_hw_show,
 397 };
 398
 399 static struct queue_sysfs_entry queue_discard_max_entry = {
 400         .attr = {.name = "discard_max_bytes", .mode = S_IRUGO | S_IWUSR },
 401         .show = queue_discard_max_show,
 402         .store = queue_discard_max_store,
 403 };
 404
 405 static struct queue_sysfs_entry queue_discard_zeroes_data_entry = {
 406         .attr = {.name = "discard_zeroes_data", .mode = S_IRUGO },
 407         .show = queue_discard_zeroes_data_show,
 408 };
 409
 410 static struct queue_sysfs_entry queue_write_same_max_entry = {
 411         .attr = {.name = "write_same_max_bytes", .mode = S_IRUGO },
 412         .show = queue_write_same_max_show,
 413 };
 414
 415 static struct queue_sysfs_entry queue_nonrot_entry = {
 416         .attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR },
 417         .show = queue_show_nonrot,
 418         .store = queue_store_nonrot,
 419 };
 420
 421 static struct queue_sysfs_entry queue_nomerges_entry = {
 422         .attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR },
 423         .show = queue_nomerges_show,
 424         .store = queue_nomerges_store,
 425 };
 426
 427 static struct queue_sysfs_entry queue_rq_affinity_entry = {
 428         .attr = {.name = "rq_affinity", .mode = S_IRUGO | S_IWUSR },
 429         .show = queue_rq_affinity_show,
 430         .store = queue_rq_affinity_store,
 431 };
 432
 433 static struct queue_sysfs_entry queue_iostats_entry = {
 434         .attr = {.name = "iostats", .mode = S_IRUGO | S_IWUSR },
 435         .show = queue_show_iostats,
 436         .store = queue_store_iostats,
 437 };
 438
 439 static struct queue_sysfs_entry queue_random_entry = {
 440         .attr = {.name = "add_random", .mode = S_IRUGO | S_IWUSR },
 441         .show = queue_show_random,
 442         .store = queue_store_random,
 443 };
 444
 445 static struct attribute *default_attrs[] = {
 446         &queue_requests_entry.attr,
 447         &queue_ra_entry.attr,
 448         &queue_max_hw_sectors_entry.attr,
 449         &queue_max_sectors_entry.attr,
 450         &queue_max_segments_entry.attr,
 451         &queue_max_integrity_segments_entry.attr,
 452         &queue_max_segment_size_entry.attr,
 453         &queue_iosched_entry.attr,
 454         &queue_hw_sector_size_entry.attr,
 455         &queue_logical_block_size_entry.attr,
 456         &queue_physical_block_size_entry.attr,
 457         &queue_io_min_entry.attr,
 458         &queue_io_opt_entry.attr,
 459         &queue_discard_granularity_entry.attr,
 460         &queue_discard_max_entry.attr,
 461         &queue_discard_max_hw_entry.attr,
 462         &queue_discard_zeroes_data_entry.attr,
 463         &queue_write_same_max_entry.attr,
 464         &queue_nonrot_entry.attr,
 465         &queue_nomerges_entry.attr,
 466         &queue_rq_affinity_entry.attr,
 467         &queue_iostats_entry.attr,
 468         &queue_random_entry.attr,
 469         NULL,
 470 };
 471
 472 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
 473
 474 static ssize_t
 475 queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
 476 {
 477         struct queue_sysfs_entry *entry = to_queue(attr);
 478         struct request_queue *q =
 479                 container_of(kobj, struct request_queue, kobj);
 480         ssize_t res;
 481
 482         if (!entry->show)
 483                 return -EIO;
 484         mutex_lock(&q->sysfs_lock);
 485         if (blk_queue_dying(q)) {
 486                 mutex_unlock(&q->sysfs_lock);
 487                 return -ENOENT;
 488         }
 489         res = entry->show(q, page);
 490         mutex_unlock(&q->sysfs_lock);
 491         return res;
 492 }
 493
 494 static ssize_t
 495 queue_attr_store(struct kobject *kobj, struct attribute *attr,
 496                     const char *page, size_t length)
 497 {
 498         struct queue_sysfs_entry *entry = to_queue(attr);
 499         struct request_queue *q;
 500         ssize_t res;
 501
 502         if (!entry->store)
 503                 return -EIO;
 504
 505         q = container_of(kobj, struct request_queue, kobj);
 506         mutex_lock(&q->sysfs_lock);
 507         if (blk_queue_dying(q)) {
 508                 mutex_unlock(&q->sysfs_lock);
 509                 return -ENOENT;
 510         }
 511         res = entry->store(q, page, length);
 512         mutex_unlock(&q->sysfs_lock);
 513         return res;
 514 }
 515
 516 static void blk_free_queue_rcu(struct rcu_head *rcu_head)
 517 {
 518         struct request_queue *q = container_of(rcu_head, struct request_queue,
 519                                                rcu_head);
 520         kmem_cache_free(blk_requestq_cachep, q);
 521 }
 522
 523 /**
 524  * blk_release_queue: - release a &struct request_queue when it is no longer needed
 525  * @kobj:    the kobj belonging to the request queue to be released
 526  *
 527  * Description:
 528  *     blk_release_queue is the pair to blk_init_queue() or
 529  *     blk_queue_make_request().  It should be called when a request queue is
 530  *     being released; typically when a block device is being de-registered.
 531  *     Currently, its primary task it to free all the &struct request
 532  *     structures that were allocated to the queue and the queue itself.
 533  *
 534  * Note:
 535  *     The low level driver must have finished any outstanding requests first
 536  *     via blk_cleanup_queue().
 537  **/
 538 static void blk_release_queue(struct kobject *kobj)
 539 {
 540         struct request_queue *q =
 541                 container_of(kobj, struct request_queue, kobj);
 542
 543         blkcg_exit_queue(q);
 544
 545         if (q->elevator) {
 546                 spin_lock_irq(q->queue_lock);
 547                 ioc_clear_queue(q);
 548                 spin_unlock_irq(q->queue_lock);
 549                 elevator_exit(q->elevator);
 550         }
 551
 552         blk_exit_rl(&q->root_rl);
 553
 554         if (q->queue_tags)
 555                 __blk_queue_free_tags(q);
 556
 557         if (!q->mq_ops)
 558                 blk_free_flush_queue(q->fq);
 559         else
 560                 blk_mq_release(q);
 561
 562         blk_trace_shutdown(q);
 563
 564         if (q->bio_split)
 565                 bioset_free(q->bio_split);
 566
 567         ida_simple_remove(&blk_queue_ida, q->id);
 568         call_rcu(&q->rcu_head, blk_free_queue_rcu);
 569 }
 570
 571 static const struct sysfs_ops queue_sysfs_ops = {
 572         .show   = queue_attr_show,
 573         .store  = queue_attr_store,
 574 };
 575
 576 struct kobj_type blk_queue_ktype = {
 577         .sysfs_ops      = &queue_sysfs_ops,
 578         .default_attrs  = default_attrs,
 579         .release        = blk_release_queue,
 580 };
 581
 582 int blk_register_queue(struct gendisk *disk)
 583 {
 584         int ret;
 585         struct device *dev = disk_to_dev(disk);
 586         struct request_queue *q = disk->queue;
 587
 588         if (WARN_ON(!q))
 589                 return -ENXIO;
 590
 591         /*
 592          * SCSI probing may synchronously create and destroy a lot of
 593          * request_queues for non-existent devices.  Shutting down a fully
 594          * functional queue takes measureable wallclock time as RCU grace
 595          * periods are involved.  To avoid excessive latency in these
 596          * cases, a request_queue starts out in a degraded mode which is
 597          * faster to shut down and is made fully functional here as
 598          * request_queues for non-existent devices never get registered.
 599          */
 600         if (!blk_queue_init_done(q)) {
 601                 queue_flag_set_unlocked(QUEUE_FLAG_INIT_DONE, q);
 602                 blk_queue_bypass_end(q);
 603                 if (q->mq_ops)
 604                         blk_mq_finish_init(q);
 605         }
 606
 607         ret = blk_trace_init_sysfs(dev);
 608         if (ret)
 609                 return ret;
 610
 611         ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
 612         if (ret < 0) {
 613                 blk_trace_remove_sysfs(dev);
 614                 return ret;
 615         }
 616
 617         kobject_uevent(&q->kobj, KOBJ_ADD);
 618
 619         if (q->mq_ops)
 620                 blk_mq_register_disk(disk);
 621
 622         if (!q->request_fn)
 623                 return 0;
 624
 625         ret = elv_register_queue(q);
 626         if (ret) {
 627                 kobject_uevent(&q->kobj, KOBJ_REMOVE);
 628                 kobject_del(&q->kobj);
 629                 blk_trace_remove_sysfs(dev);
 630                 kobject_put(&dev->kobj);
 631                 return ret;
 632         }
 633
 634         return 0;
 635 }
 636
 637 void blk_unregister_queue(struct gendisk *disk)
 638 {
 639         struct request_queue *q = disk->queue;
 640
 641         if (WARN_ON(!q))
 642                 return;
 643
 644         if (q->mq_ops)
 645                 blk_mq_unregister_disk(disk);
 646
 647         if (q->request_fn)
 648                 elv_unregister_queue(q);
 649
 650         kobject_uevent(&q->kobj, KOBJ_REMOVE);
 651         kobject_del(&q->kobj);
 652         blk_trace_remove_sysfs(disk_to_dev(disk));
 653         kobject_put(&disk_to_dev(disk)->kobj);
 654 }