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 bdi_exit(&q->backing_dev_info); 544 blkcg_exit_queue(q); 545 546 if (q->elevator) { 547 spin_lock_irq(q->queue_lock); 548 ioc_clear_queue(q); 549 spin_unlock_irq(q->queue_lock); 550 elevator_exit(q->elevator); 551 } 552 553 blk_exit_rl(&q->root_rl); 554 555 if (q->queue_tags) 556 __blk_queue_free_tags(q); 557 558 if (!q->mq_ops) 559 blk_free_flush_queue(q->fq); 560 else 561 blk_mq_release(q); 562 563 blk_trace_shutdown(q); 564 565 if (q->bio_split) 566 bioset_free(q->bio_split); 567 568 ida_simple_remove(&blk_queue_ida, q->id); 569 call_rcu(&q->rcu_head, blk_free_queue_rcu); 570 } 571 572 static const struct sysfs_ops queue_sysfs_ops = { 573 .show = queue_attr_show, 574 .store = queue_attr_store, 575 }; 576 577 struct kobj_type blk_queue_ktype = { 578 .sysfs_ops = &queue_sysfs_ops, 579 .default_attrs = default_attrs, 580 .release = blk_release_queue, 581 }; 582 583 int blk_register_queue(struct gendisk *disk) 584 { 585 int ret; 586 struct device *dev = disk_to_dev(disk); 587 struct request_queue *q = disk->queue; 588 589 if (WARN_ON(!q)) 590 return -ENXIO; 591 592 /* 593 * SCSI probing may synchronously create and destroy a lot of 594 * request_queues for non-existent devices. Shutting down a fully 595 * functional queue takes measureable wallclock time as RCU grace 596 * periods are involved. To avoid excessive latency in these 597 * cases, a request_queue starts out in a degraded mode which is 598 * faster to shut down and is made fully functional here as 599 * request_queues for non-existent devices never get registered. 600 */ 601 if (!blk_queue_init_done(q)) { 602 queue_flag_set_unlocked(QUEUE_FLAG_INIT_DONE, q); 603 blk_queue_bypass_end(q); 604 if (q->mq_ops) 605 blk_mq_finish_init(q); 606 } 607 608 ret = blk_trace_init_sysfs(dev); 609 if (ret) 610 return ret; 611 612 ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue"); 613 if (ret < 0) { 614 blk_trace_remove_sysfs(dev); 615 return ret; 616 } 617 618 kobject_uevent(&q->kobj, KOBJ_ADD); 619 620 if (q->mq_ops) 621 blk_mq_register_disk(disk); 622 623 if (!q->request_fn) 624 return 0; 625 626 ret = elv_register_queue(q); 627 if (ret) { 628 kobject_uevent(&q->kobj, KOBJ_REMOVE); 629 kobject_del(&q->kobj); 630 blk_trace_remove_sysfs(dev); 631 kobject_put(&dev->kobj); 632 return ret; 633 } 634 635 return 0; 636 } 637 638 void blk_unregister_queue(struct gendisk *disk) 639 { 640 struct request_queue *q = disk->queue; 641 642 if (WARN_ON(!q)) 643 return; 644 645 if (q->mq_ops) 646 blk_mq_unregister_disk(disk); 647 648 if (q->request_fn) 649 elv_unregister_queue(q); 650 651 kobject_uevent(&q->kobj, KOBJ_REMOVE); 652 kobject_del(&q->kobj); 653 blk_trace_remove_sysfs(disk_to_dev(disk)); 654 kobject_put(&disk_to_dev(disk)->kobj); 655 } 656