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