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