1// SPDX-License-Identifier: GPL-2.0-only 2/* 3 * Add configfs and memory store: Kyungchan Koh <kkc6196@fb.com> and 4 * Shaohua Li <shli@fb.com> 5 */ 6#include <linux/module.h> 7 8#include <linux/moduleparam.h> 9#include <linux/sched.h> 10#include <linux/fs.h> 11#include <linux/init.h> 12#include "null_blk.h" 13 14#undef pr_fmt 15#define pr_fmt(fmt) "null_blk: " fmt 16 17#define FREE_BATCH 16 18 19#define TICKS_PER_SEC 50ULL 20#define TIMER_INTERVAL (NSEC_PER_SEC / TICKS_PER_SEC) 21 22#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION 23static DECLARE_FAULT_ATTR(null_timeout_attr); 24static DECLARE_FAULT_ATTR(null_requeue_attr); 25static DECLARE_FAULT_ATTR(null_init_hctx_attr); 26#endif 27 28static inline u64 mb_per_tick(int mbps) 29{ 30 return (1 << 20) / TICKS_PER_SEC * ((u64) mbps); 31} 32 33/* 34 * Status flags for nullb_device. 35 * 36 * CONFIGURED: Device has been configured and turned on. Cannot reconfigure. 37 * UP: Device is currently on and visible in userspace. 38 * THROTTLED: Device is being throttled. 39 * CACHE: Device is using a write-back cache. 40 */ 41enum nullb_device_flags { 42 NULLB_DEV_FL_CONFIGURED = 0, 43 NULLB_DEV_FL_UP = 1, 44 NULLB_DEV_FL_THROTTLED = 2, 45 NULLB_DEV_FL_CACHE = 3, 46}; 47 48#define MAP_SZ ((PAGE_SIZE >> SECTOR_SHIFT) + 2) 49/* 50 * nullb_page is a page in memory for nullb devices. 51 * 52 * @page: The page holding the data. 53 * @bitmap: The bitmap represents which sector in the page has data. 54 * Each bit represents one block size. For example, sector 8 55 * will use the 7th bit 56 * The highest 2 bits of bitmap are for special purpose. LOCK means the cache 57 * page is being flushing to storage. FREE means the cache page is freed and 58 * should be skipped from flushing to storage. Please see 59 * null_make_cache_space 60 */ 61struct nullb_page { 62 struct page *page; 63 DECLARE_BITMAP(bitmap, MAP_SZ); 64}; 65#define NULLB_PAGE_LOCK (MAP_SZ - 1) 66#define NULLB_PAGE_FREE (MAP_SZ - 2) 67 68static LIST_HEAD(nullb_list); 69static struct mutex lock; 70static int null_major; 71static DEFINE_IDA(nullb_indexes); 72static struct blk_mq_tag_set tag_set; 73 74enum { 75 NULL_IRQ_NONE = 0, 76 NULL_IRQ_SOFTIRQ = 1, 77 NULL_IRQ_TIMER = 2, 78}; 79 80static bool g_virt_boundary = false; 81module_param_named(virt_boundary, g_virt_boundary, bool, 0444); 82MODULE_PARM_DESC(virt_boundary, "Require a virtual boundary for the device. Default: False"); 83 84static int g_no_sched; 85module_param_named(no_sched, g_no_sched, int, 0444); 86MODULE_PARM_DESC(no_sched, "No io scheduler"); 87 88static int g_submit_queues = 1; 89module_param_named(submit_queues, g_submit_queues, int, 0444); 90MODULE_PARM_DESC(submit_queues, "Number of submission queues"); 91 92static int g_poll_queues = 1; 93module_param_named(poll_queues, g_poll_queues, int, 0444); 94MODULE_PARM_DESC(poll_queues, "Number of IOPOLL submission queues"); 95 96static int g_home_node = NUMA_NO_NODE; 97module_param_named(home_node, g_home_node, int, 0444); 98MODULE_PARM_DESC(home_node, "Home node for the device"); 99 100#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION 101/* 102 * For more details about fault injection, please refer to 103 * Documentation/fault-injection/fault-injection.rst. 104 */ 105static char g_timeout_str[80]; 106module_param_string(timeout, g_timeout_str, sizeof(g_timeout_str), 0444); 107MODULE_PARM_DESC(timeout, "Fault injection. timeout=<interval>,<probability>,<space>,<times>"); 108 109static char g_requeue_str[80]; 110module_param_string(requeue, g_requeue_str, sizeof(g_requeue_str), 0444); 111MODULE_PARM_DESC(requeue, "Fault injection. requeue=<interval>,<probability>,<space>,<times>"); 112 113static char g_init_hctx_str[80]; 114module_param_string(init_hctx, g_init_hctx_str, sizeof(g_init_hctx_str), 0444); 115MODULE_PARM_DESC(init_hctx, "Fault injection to fail hctx init. init_hctx=<interval>,<probability>,<space>,<times>"); 116#endif 117 118static int g_queue_mode = NULL_Q_MQ; 119 120static int null_param_store_val(const char *str, int *val, int min, int max) 121{ 122 int ret, new_val; 123 124 ret = kstrtoint(str, 10, &new_val); 125 if (ret) 126 return -EINVAL; 127 128 if (new_val < min || new_val > max) 129 return -EINVAL; 130 131 *val = new_val; 132 return 0; 133} 134 135static int null_set_queue_mode(const char *str, const struct kernel_param *kp) 136{ 137 return null_param_store_val(str, &g_queue_mode, NULL_Q_BIO, NULL_Q_MQ); 138} 139 140static const struct kernel_param_ops null_queue_mode_param_ops = { 141 .set = null_set_queue_mode, 142 .get = param_get_int, 143}; 144 145device_param_cb(queue_mode, &null_queue_mode_param_ops, &g_queue_mode, 0444); 146MODULE_PARM_DESC(queue_mode, "Block interface to use (0=bio,1=rq,2=multiqueue)"); 147 148static int g_gb = 250; 149module_param_named(gb, g_gb, int, 0444); 150MODULE_PARM_DESC(gb, "Size in GB"); 151 152static int g_bs = 512; 153module_param_named(bs, g_bs, int, 0444); 154MODULE_PARM_DESC(bs, "Block size (in bytes)"); 155 156static int g_max_sectors; 157module_param_named(max_sectors, g_max_sectors, int, 0444); 158MODULE_PARM_DESC(max_sectors, "Maximum size of a command (in 512B sectors)"); 159 160static unsigned int nr_devices = 1; 161module_param(nr_devices, uint, 0444); 162MODULE_PARM_DESC(nr_devices, "Number of devices to register"); 163 164static bool g_blocking; 165module_param_named(blocking, g_blocking, bool, 0444); 166MODULE_PARM_DESC(blocking, "Register as a blocking blk-mq driver device"); 167 168static bool shared_tags; 169module_param(shared_tags, bool, 0444); 170MODULE_PARM_DESC(shared_tags, "Share tag set between devices for blk-mq"); 171 172static bool g_shared_tag_bitmap; 173module_param_named(shared_tag_bitmap, g_shared_tag_bitmap, bool, 0444); 174MODULE_PARM_DESC(shared_tag_bitmap, "Use shared tag bitmap for all submission queues for blk-mq"); 175 176static int g_irqmode = NULL_IRQ_SOFTIRQ; 177 178static int null_set_irqmode(const char *str, const struct kernel_param *kp) 179{ 180 return null_param_store_val(str, &g_irqmode, NULL_IRQ_NONE, 181 NULL_IRQ_TIMER); 182} 183 184static const struct kernel_param_ops null_irqmode_param_ops = { 185 .set = null_set_irqmode, 186 .get = param_get_int, 187}; 188 189device_param_cb(irqmode, &null_irqmode_param_ops, &g_irqmode, 0444); 190MODULE_PARM_DESC(irqmode, "IRQ completion handler. 0-none, 1-softirq, 2-timer"); 191 192static unsigned long g_completion_nsec = 10000; 193module_param_named(completion_nsec, g_completion_nsec, ulong, 0444); 194MODULE_PARM_DESC(completion_nsec, "Time in ns to complete a request in hardware. Default: 10,000ns"); 195 196static int g_hw_queue_depth = 64; 197module_param_named(hw_queue_depth, g_hw_queue_depth, int, 0444); 198MODULE_PARM_DESC(hw_queue_depth, "Queue depth for each hardware queue. Default: 64"); 199 200static bool g_use_per_node_hctx; 201module_param_named(use_per_node_hctx, g_use_per_node_hctx, bool, 0444); 202MODULE_PARM_DESC(use_per_node_hctx, "Use per-node allocation for hardware context queues. Default: false"); 203 204static bool g_memory_backed; 205module_param_named(memory_backed, g_memory_backed, bool, 0444); 206MODULE_PARM_DESC(memory_backed, "Create a memory-backed block device. Default: false"); 207 208static bool g_discard; 209module_param_named(discard, g_discard, bool, 0444); 210MODULE_PARM_DESC(discard, "Support discard operations (requires memory-backed null_blk device). Default: false"); 211 212static unsigned long g_cache_size; 213module_param_named(cache_size, g_cache_size, ulong, 0444); 214MODULE_PARM_DESC(mbps, "Cache size in MiB for memory-backed device. Default: 0 (none)"); 215 216static unsigned int g_mbps; 217module_param_named(mbps, g_mbps, uint, 0444); 218MODULE_PARM_DESC(mbps, "Limit maximum bandwidth (in MiB/s). Default: 0 (no limit)"); 219 220static bool g_zoned; 221module_param_named(zoned, g_zoned, bool, S_IRUGO); 222MODULE_PARM_DESC(zoned, "Make device as a host-managed zoned block device. Default: false"); 223 224static unsigned long g_zone_size = 256; 225module_param_named(zone_size, g_zone_size, ulong, S_IRUGO); 226MODULE_PARM_DESC(zone_size, "Zone size in MB when block device is zoned. Must be power-of-two: Default: 256"); 227 228static unsigned long g_zone_capacity; 229module_param_named(zone_capacity, g_zone_capacity, ulong, 0444); 230MODULE_PARM_DESC(zone_capacity, "Zone capacity in MB when block device is zoned. Can be less than or equal to zone size. Default: Zone size"); 231 232static unsigned int g_zone_nr_conv; 233module_param_named(zone_nr_conv, g_zone_nr_conv, uint, 0444); 234MODULE_PARM_DESC(zone_nr_conv, "Number of conventional zones when block device is zoned. Default: 0"); 235 236static unsigned int g_zone_max_open; 237module_param_named(zone_max_open, g_zone_max_open, uint, 0444); 238MODULE_PARM_DESC(zone_max_open, "Maximum number of open zones when block device is zoned. Default: 0 (no limit)"); 239 240static unsigned int g_zone_max_active; 241module_param_named(zone_max_active, g_zone_max_active, uint, 0444); 242MODULE_PARM_DESC(zone_max_active, "Maximum number of active zones when block device is zoned. Default: 0 (no limit)"); 243 244static struct nullb_device *null_alloc_dev(void); 245static void null_free_dev(struct nullb_device *dev); 246static void null_del_dev(struct nullb *nullb); 247static int null_add_dev(struct nullb_device *dev); 248static struct nullb *null_find_dev_by_name(const char *name); 249static void null_free_device_storage(struct nullb_device *dev, bool is_cache); 250 251static inline struct nullb_device *to_nullb_device(struct config_item *item) 252{ 253 return item ? container_of(to_config_group(item), struct nullb_device, group) : NULL; 254} 255 256static inline ssize_t nullb_device_uint_attr_show(unsigned int val, char *page) 257{ 258 return snprintf(page, PAGE_SIZE, "%u\n", val); 259} 260 261static inline ssize_t nullb_device_ulong_attr_show(unsigned long val, 262 char *page) 263{ 264 return snprintf(page, PAGE_SIZE, "%lu\n", val); 265} 266 267static inline ssize_t nullb_device_bool_attr_show(bool val, char *page) 268{ 269 return snprintf(page, PAGE_SIZE, "%u\n", val); 270} 271 272static ssize_t nullb_device_uint_attr_store(unsigned int *val, 273 const char *page, size_t count) 274{ 275 unsigned int tmp; 276 int result; 277 278 result = kstrtouint(page, 0, &tmp); 279 if (result < 0) 280 return result; 281 282 *val = tmp; 283 return count; 284} 285 286static ssize_t nullb_device_ulong_attr_store(unsigned long *val, 287 const char *page, size_t count) 288{ 289 int result; 290 unsigned long tmp; 291 292 result = kstrtoul(page, 0, &tmp); 293 if (result < 0) 294 return result; 295 296 *val = tmp; 297 return count; 298} 299 300static ssize_t nullb_device_bool_attr_store(bool *val, const char *page, 301 size_t count) 302{ 303 bool tmp; 304 int result; 305 306 result = kstrtobool(page, &tmp); 307 if (result < 0) 308 return result; 309 310 *val = tmp; 311 return count; 312} 313 314/* The following macro should only be used with TYPE = {uint, ulong, bool}. */ 315#define NULLB_DEVICE_ATTR(NAME, TYPE, APPLY) \ 316static ssize_t \ 317nullb_device_##NAME##_show(struct config_item *item, char *page) \ 318{ \ 319 return nullb_device_##TYPE##_attr_show( \ 320 to_nullb_device(item)->NAME, page); \ 321} \ 322static ssize_t \ 323nullb_device_##NAME##_store(struct config_item *item, const char *page, \ 324 size_t count) \ 325{ \ 326 int (*apply_fn)(struct nullb_device *dev, TYPE new_value) = APPLY;\ 327 struct nullb_device *dev = to_nullb_device(item); \ 328 TYPE new_value = 0; \ 329 int ret; \ 330 \ 331 ret = nullb_device_##TYPE##_attr_store(&new_value, page, count);\ 332 if (ret < 0) \ 333 return ret; \ 334 if (apply_fn) \ 335 ret = apply_fn(dev, new_value); \ 336 else if (test_bit(NULLB_DEV_FL_CONFIGURED, &dev->flags)) \ 337 ret = -EBUSY; \ 338 if (ret < 0) \ 339 return ret; \ 340 dev->NAME = new_value; \ 341 return count; \ 342} \ 343CONFIGFS_ATTR(nullb_device_, NAME); 344 345static int nullb_update_nr_hw_queues(struct nullb_device *dev, 346 unsigned int submit_queues, 347 unsigned int poll_queues) 348 349{ 350 struct blk_mq_tag_set *set; 351 int ret, nr_hw_queues; 352 353 if (!dev->nullb) 354 return 0; 355 356 /* 357 * Make sure at least one submit queue exists. 358 */ 359 if (!submit_queues) 360 return -EINVAL; 361 362 /* 363 * Make sure that null_init_hctx() does not access nullb->queues[] past 364 * the end of that array. 365 */ 366 if (submit_queues > nr_cpu_ids || poll_queues > g_poll_queues) 367 return -EINVAL; 368 369 /* 370 * Keep previous and new queue numbers in nullb_device for reference in 371 * the call back function null_map_queues(). 372 */ 373 dev->prev_submit_queues = dev->submit_queues; 374 dev->prev_poll_queues = dev->poll_queues; 375 dev->submit_queues = submit_queues; 376 dev->poll_queues = poll_queues; 377 378 set = dev->nullb->tag_set; 379 nr_hw_queues = submit_queues + poll_queues; 380 blk_mq_update_nr_hw_queues(set, nr_hw_queues); 381 ret = set->nr_hw_queues == nr_hw_queues ? 0 : -ENOMEM; 382 383 if (ret) { 384 /* on error, revert the queue numbers */ 385 dev->submit_queues = dev->prev_submit_queues; 386 dev->poll_queues = dev->prev_poll_queues; 387 } 388 389 return ret; 390} 391 392static int nullb_apply_submit_queues(struct nullb_device *dev, 393 unsigned int submit_queues) 394{ 395 return nullb_update_nr_hw_queues(dev, submit_queues, dev->poll_queues); 396} 397 398static int nullb_apply_poll_queues(struct nullb_device *dev, 399 unsigned int poll_queues) 400{ 401 return nullb_update_nr_hw_queues(dev, dev->submit_queues, poll_queues); 402} 403 404NULLB_DEVICE_ATTR(size, ulong, NULL); 405NULLB_DEVICE_ATTR(completion_nsec, ulong, NULL); 406NULLB_DEVICE_ATTR(submit_queues, uint, nullb_apply_submit_queues); 407NULLB_DEVICE_ATTR(poll_queues, uint, nullb_apply_poll_queues); 408NULLB_DEVICE_ATTR(home_node, uint, NULL); 409NULLB_DEVICE_ATTR(queue_mode, uint, NULL); 410NULLB_DEVICE_ATTR(blocksize, uint, NULL); 411NULLB_DEVICE_ATTR(max_sectors, uint, NULL); 412NULLB_DEVICE_ATTR(irqmode, uint, NULL); 413NULLB_DEVICE_ATTR(hw_queue_depth, uint, NULL); 414NULLB_DEVICE_ATTR(index, uint, NULL); 415NULLB_DEVICE_ATTR(blocking, bool, NULL); 416NULLB_DEVICE_ATTR(use_per_node_hctx, bool, NULL); 417NULLB_DEVICE_ATTR(memory_backed, bool, NULL); 418NULLB_DEVICE_ATTR(discard, bool, NULL); 419NULLB_DEVICE_ATTR(mbps, uint, NULL); 420NULLB_DEVICE_ATTR(cache_size, ulong, NULL); 421NULLB_DEVICE_ATTR(zoned, bool, NULL); 422NULLB_DEVICE_ATTR(zone_size, ulong, NULL); 423NULLB_DEVICE_ATTR(zone_capacity, ulong, NULL); 424NULLB_DEVICE_ATTR(zone_nr_conv, uint, NULL); 425NULLB_DEVICE_ATTR(zone_max_open, uint, NULL); 426NULLB_DEVICE_ATTR(zone_max_active, uint, NULL); 427NULLB_DEVICE_ATTR(virt_boundary, bool, NULL); 428NULLB_DEVICE_ATTR(no_sched, bool, NULL); 429NULLB_DEVICE_ATTR(shared_tag_bitmap, bool, NULL); 430 431static ssize_t nullb_device_power_show(struct config_item *item, char *page) 432{ 433 return nullb_device_bool_attr_show(to_nullb_device(item)->power, page); 434} 435 436static ssize_t nullb_device_power_store(struct config_item *item, 437 const char *page, size_t count) 438{ 439 struct nullb_device *dev = to_nullb_device(item); 440 bool newp = false; 441 ssize_t ret; 442 443 ret = nullb_device_bool_attr_store(&newp, page, count); 444 if (ret < 0) 445 return ret; 446 447 if (!dev->power && newp) { 448 if (test_and_set_bit(NULLB_DEV_FL_UP, &dev->flags)) 449 return count; 450 ret = null_add_dev(dev); 451 if (ret) { 452 clear_bit(NULLB_DEV_FL_UP, &dev->flags); 453 return ret; 454 } 455 456 set_bit(NULLB_DEV_FL_CONFIGURED, &dev->flags); 457 dev->power = newp; 458 } else if (dev->power && !newp) { 459 if (test_and_clear_bit(NULLB_DEV_FL_UP, &dev->flags)) { 460 mutex_lock(&lock); 461 dev->power = newp; 462 null_del_dev(dev->nullb); 463 mutex_unlock(&lock); 464 } 465 clear_bit(NULLB_DEV_FL_CONFIGURED, &dev->flags); 466 } 467 468 return count; 469} 470 471CONFIGFS_ATTR(nullb_device_, power); 472 473static ssize_t nullb_device_badblocks_show(struct config_item *item, char *page) 474{ 475 struct nullb_device *t_dev = to_nullb_device(item); 476 477 return badblocks_show(&t_dev->badblocks, page, 0); 478} 479 480static ssize_t nullb_device_badblocks_store(struct config_item *item, 481 const char *page, size_t count) 482{ 483 struct nullb_device *t_dev = to_nullb_device(item); 484 char *orig, *buf, *tmp; 485 u64 start, end; 486 int ret; 487 488 orig = kstrndup(page, count, GFP_KERNEL); 489 if (!orig) 490 return -ENOMEM; 491 492 buf = strstrip(orig); 493 494 ret = -EINVAL; 495 if (buf[0] != '+' && buf[0] != '-') 496 goto out; 497 tmp = strchr(&buf[1], '-'); 498 if (!tmp) 499 goto out; 500 *tmp = '\0'; 501 ret = kstrtoull(buf + 1, 0, &start); 502 if (ret) 503 goto out; 504 ret = kstrtoull(tmp + 1, 0, &end); 505 if (ret) 506 goto out; 507 ret = -EINVAL; 508 if (start > end) 509 goto out; 510 /* enable badblocks */ 511 cmpxchg(&t_dev->badblocks.shift, -1, 0); 512 if (buf[0] == '+') 513 ret = badblocks_set(&t_dev->badblocks, start, 514 end - start + 1, 1); 515 else 516 ret = badblocks_clear(&t_dev->badblocks, start, 517 end - start + 1); 518 if (ret == 0) 519 ret = count; 520out: 521 kfree(orig); 522 return ret; 523} 524CONFIGFS_ATTR(nullb_device_, badblocks); 525 526static ssize_t nullb_device_zone_readonly_store(struct config_item *item, 527 const char *page, size_t count) 528{ 529 struct nullb_device *dev = to_nullb_device(item); 530 531 return zone_cond_store(dev, page, count, BLK_ZONE_COND_READONLY); 532} 533CONFIGFS_ATTR_WO(nullb_device_, zone_readonly); 534 535static ssize_t nullb_device_zone_offline_store(struct config_item *item, 536 const char *page, size_t count) 537{ 538 struct nullb_device *dev = to_nullb_device(item); 539 540 return zone_cond_store(dev, page, count, BLK_ZONE_COND_OFFLINE); 541} 542CONFIGFS_ATTR_WO(nullb_device_, zone_offline); 543 544static struct configfs_attribute *nullb_device_attrs[] = { 545 &nullb_device_attr_size, 546 &nullb_device_attr_completion_nsec, 547 &nullb_device_attr_submit_queues, 548 &nullb_device_attr_poll_queues, 549 &nullb_device_attr_home_node, 550 &nullb_device_attr_queue_mode, 551 &nullb_device_attr_blocksize, 552 &nullb_device_attr_max_sectors, 553 &nullb_device_attr_irqmode, 554 &nullb_device_attr_hw_queue_depth, 555 &nullb_device_attr_index, 556 &nullb_device_attr_blocking, 557 &nullb_device_attr_use_per_node_hctx, 558 &nullb_device_attr_power, 559 &nullb_device_attr_memory_backed, 560 &nullb_device_attr_discard, 561 &nullb_device_attr_mbps, 562 &nullb_device_attr_cache_size, 563 &nullb_device_attr_badblocks, 564 &nullb_device_attr_zoned, 565 &nullb_device_attr_zone_size, 566 &nullb_device_attr_zone_capacity, 567 &nullb_device_attr_zone_nr_conv, 568 &nullb_device_attr_zone_max_open, 569 &nullb_device_attr_zone_max_active, 570 &nullb_device_attr_zone_readonly, 571 &nullb_device_attr_zone_offline, 572 &nullb_device_attr_virt_boundary, 573 &nullb_device_attr_no_sched, 574 &nullb_device_attr_shared_tag_bitmap, 575 NULL, 576}; 577 578static void nullb_device_release(struct config_item *item) 579{ 580 struct nullb_device *dev = to_nullb_device(item); 581 582 null_free_device_storage(dev, false); 583 null_free_dev(dev); 584} 585 586static struct configfs_item_operations nullb_device_ops = { 587 .release = nullb_device_release, 588}; 589 590static const struct config_item_type nullb_device_type = { 591 .ct_item_ops = &nullb_device_ops, 592 .ct_attrs = nullb_device_attrs, 593 .ct_owner = THIS_MODULE, 594}; 595 596#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION 597 598static void nullb_add_fault_config(struct nullb_device *dev) 599{ 600 fault_config_init(&dev->timeout_config, "timeout_inject"); 601 fault_config_init(&dev->requeue_config, "requeue_inject"); 602 fault_config_init(&dev->init_hctx_fault_config, "init_hctx_fault_inject"); 603 604 configfs_add_default_group(&dev->timeout_config.group, &dev->group); 605 configfs_add_default_group(&dev->requeue_config.group, &dev->group); 606 configfs_add_default_group(&dev->init_hctx_fault_config.group, &dev->group); 607} 608 609#else 610 611static void nullb_add_fault_config(struct nullb_device *dev) 612{ 613} 614 615#endif 616 617static struct 618config_group *nullb_group_make_group(struct config_group *group, const char *name) 619{ 620 struct nullb_device *dev; 621 622 if (null_find_dev_by_name(name)) 623 return ERR_PTR(-EEXIST); 624 625 dev = null_alloc_dev(); 626 if (!dev) 627 return ERR_PTR(-ENOMEM); 628 629 config_group_init_type_name(&dev->group, name, &nullb_device_type); 630 nullb_add_fault_config(dev); 631 632 return &dev->group; 633} 634 635static void 636nullb_group_drop_item(struct config_group *group, struct config_item *item) 637{ 638 struct nullb_device *dev = to_nullb_device(item); 639 640 if (test_and_clear_bit(NULLB_DEV_FL_UP, &dev->flags)) { 641 mutex_lock(&lock); 642 dev->power = false; 643 null_del_dev(dev->nullb); 644 mutex_unlock(&lock); 645 } 646 647 config_item_put(item); 648} 649 650static ssize_t memb_group_features_show(struct config_item *item, char *page) 651{ 652 return snprintf(page, PAGE_SIZE, 653 "badblocks,blocking,blocksize,cache_size," 654 "completion_nsec,discard,home_node,hw_queue_depth," 655 "irqmode,max_sectors,mbps,memory_backed,no_sched," 656 "poll_queues,power,queue_mode,shared_tag_bitmap,size," 657 "submit_queues,use_per_node_hctx,virt_boundary,zoned," 658 "zone_capacity,zone_max_active,zone_max_open," 659 "zone_nr_conv,zone_offline,zone_readonly,zone_size\n"); 660} 661 662CONFIGFS_ATTR_RO(memb_group_, features); 663 664static struct configfs_attribute *nullb_group_attrs[] = { 665 &memb_group_attr_features, 666 NULL, 667}; 668 669static struct configfs_group_operations nullb_group_ops = { 670 .make_group = nullb_group_make_group, 671 .drop_item = nullb_group_drop_item, 672}; 673 674static const struct config_item_type nullb_group_type = { 675 .ct_group_ops = &nullb_group_ops, 676 .ct_attrs = nullb_group_attrs, 677 .ct_owner = THIS_MODULE, 678}; 679 680static struct configfs_subsystem nullb_subsys = { 681 .su_group = { 682 .cg_item = { 683 .ci_namebuf = "nullb", 684 .ci_type = &nullb_group_type, 685 }, 686 }, 687}; 688 689static inline int null_cache_active(struct nullb *nullb) 690{ 691 return test_bit(NULLB_DEV_FL_CACHE, &nullb->dev->flags); 692} 693 694static struct nullb_device *null_alloc_dev(void) 695{ 696 struct nullb_device *dev; 697 698 dev = kzalloc(sizeof(*dev), GFP_KERNEL); 699 if (!dev) 700 return NULL; 701 702#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION 703 dev->timeout_config.attr = null_timeout_attr; 704 dev->requeue_config.attr = null_requeue_attr; 705 dev->init_hctx_fault_config.attr = null_init_hctx_attr; 706#endif 707 708 INIT_RADIX_TREE(&dev->data, GFP_ATOMIC); 709 INIT_RADIX_TREE(&dev->cache, GFP_ATOMIC); 710 if (badblocks_init(&dev->badblocks, 0)) { 711 kfree(dev); 712 return NULL; 713 } 714 715 dev->size = g_gb * 1024; 716 dev->completion_nsec = g_completion_nsec; 717 dev->submit_queues = g_submit_queues; 718 dev->prev_submit_queues = g_submit_queues; 719 dev->poll_queues = g_poll_queues; 720 dev->prev_poll_queues = g_poll_queues; 721 dev->home_node = g_home_node; 722 dev->queue_mode = g_queue_mode; 723 dev->blocksize = g_bs; 724 dev->max_sectors = g_max_sectors; 725 dev->irqmode = g_irqmode; 726 dev->hw_queue_depth = g_hw_queue_depth; 727 dev->blocking = g_blocking; 728 dev->memory_backed = g_memory_backed; 729 dev->discard = g_discard; 730 dev->cache_size = g_cache_size; 731 dev->mbps = g_mbps; 732 dev->use_per_node_hctx = g_use_per_node_hctx; 733 dev->zoned = g_zoned; 734 dev->zone_size = g_zone_size; 735 dev->zone_capacity = g_zone_capacity; 736 dev->zone_nr_conv = g_zone_nr_conv; 737 dev->zone_max_open = g_zone_max_open; 738 dev->zone_max_active = g_zone_max_active; 739 dev->virt_boundary = g_virt_boundary; 740 dev->no_sched = g_no_sched; 741 dev->shared_tag_bitmap = g_shared_tag_bitmap; 742 return dev; 743} 744 745static void null_free_dev(struct nullb_device *dev) 746{ 747 if (!dev) 748 return; 749 750 null_free_zoned_dev(dev); 751 badblocks_exit(&dev->badblocks); 752 kfree(dev); 753} 754 755static void put_tag(struct nullb_queue *nq, unsigned int tag) 756{ 757 clear_bit_unlock(tag, nq->tag_map); 758 759 if (waitqueue_active(&nq->wait)) 760 wake_up(&nq->wait); 761} 762 763static unsigned int get_tag(struct nullb_queue *nq) 764{ 765 unsigned int tag; 766 767 do { 768 tag = find_first_zero_bit(nq->tag_map, nq->queue_depth); 769 if (tag >= nq->queue_depth) 770 return -1U; 771 } while (test_and_set_bit_lock(tag, nq->tag_map)); 772 773 return tag; 774} 775 776static void free_cmd(struct nullb_cmd *cmd) 777{ 778 put_tag(cmd->nq, cmd->tag); 779} 780 781static enum hrtimer_restart null_cmd_timer_expired(struct hrtimer *timer); 782 783static struct nullb_cmd *__alloc_cmd(struct nullb_queue *nq) 784{ 785 struct nullb_cmd *cmd; 786 unsigned int tag; 787 788 tag = get_tag(nq); 789 if (tag != -1U) { 790 cmd = &nq->cmds[tag]; 791 cmd->tag = tag; 792 cmd->error = BLK_STS_OK; 793 cmd->nq = nq; 794 if (nq->dev->irqmode == NULL_IRQ_TIMER) { 795 hrtimer_init(&cmd->timer, CLOCK_MONOTONIC, 796 HRTIMER_MODE_REL); 797 cmd->timer.function = null_cmd_timer_expired; 798 } 799 return cmd; 800 } 801 802 return NULL; 803} 804 805static struct nullb_cmd *alloc_cmd(struct nullb_queue *nq, struct bio *bio) 806{ 807 struct nullb_cmd *cmd; 808 DEFINE_WAIT(wait); 809 810 do { 811 /* 812 * This avoids multiple return statements, multiple calls to 813 * __alloc_cmd() and a fast path call to prepare_to_wait(). 814 */ 815 cmd = __alloc_cmd(nq); 816 if (cmd) { 817 cmd->bio = bio; 818 return cmd; 819 } 820 prepare_to_wait(&nq->wait, &wait, TASK_UNINTERRUPTIBLE); 821 io_schedule(); 822 finish_wait(&nq->wait, &wait); 823 } while (1); 824} 825 826static void end_cmd(struct nullb_cmd *cmd) 827{ 828 int queue_mode = cmd->nq->dev->queue_mode; 829 830 switch (queue_mode) { 831 case NULL_Q_MQ: 832 blk_mq_end_request(cmd->rq, cmd->error); 833 return; 834 case NULL_Q_BIO: 835 cmd->bio->bi_status = cmd->error; 836 bio_endio(cmd->bio); 837 break; 838 } 839 840 free_cmd(cmd); 841} 842 843static enum hrtimer_restart null_cmd_timer_expired(struct hrtimer *timer) 844{ 845 end_cmd(container_of(timer, struct nullb_cmd, timer)); 846 847 return HRTIMER_NORESTART; 848} 849 850static void null_cmd_end_timer(struct nullb_cmd *cmd) 851{ 852 ktime_t kt = cmd->nq->dev->completion_nsec; 853 854 hrtimer_start(&cmd->timer, kt, HRTIMER_MODE_REL); 855} 856 857static void null_complete_rq(struct request *rq) 858{ 859 end_cmd(blk_mq_rq_to_pdu(rq)); 860} 861 862static struct nullb_page *null_alloc_page(void) 863{ 864 struct nullb_page *t_page; 865 866 t_page = kmalloc(sizeof(struct nullb_page), GFP_NOIO); 867 if (!t_page) 868 return NULL; 869 870 t_page->page = alloc_pages(GFP_NOIO, 0); 871 if (!t_page->page) { 872 kfree(t_page); 873 return NULL; 874 } 875 876 memset(t_page->bitmap, 0, sizeof(t_page->bitmap)); 877 return t_page; 878} 879 880static void null_free_page(struct nullb_page *t_page) 881{ 882 __set_bit(NULLB_PAGE_FREE, t_page->bitmap); 883 if (test_bit(NULLB_PAGE_LOCK, t_page->bitmap)) 884 return; 885 __free_page(t_page->page); 886 kfree(t_page); 887} 888 889static bool null_page_empty(struct nullb_page *page) 890{ 891 int size = MAP_SZ - 2; 892 893 return find_first_bit(page->bitmap, size) == size; 894} 895 896static void null_free_sector(struct nullb *nullb, sector_t sector, 897 bool is_cache) 898{ 899 unsigned int sector_bit; 900 u64 idx; 901 struct nullb_page *t_page, *ret; 902 struct radix_tree_root *root; 903 904 root = is_cache ? &nullb->dev->cache : &nullb->dev->data; 905 idx = sector >> PAGE_SECTORS_SHIFT; 906 sector_bit = (sector & SECTOR_MASK); 907 908 t_page = radix_tree_lookup(root, idx); 909 if (t_page) { 910 __clear_bit(sector_bit, t_page->bitmap); 911 912 if (null_page_empty(t_page)) { 913 ret = radix_tree_delete_item(root, idx, t_page); 914 WARN_ON(ret != t_page); 915 null_free_page(ret); 916 if (is_cache) 917 nullb->dev->curr_cache -= PAGE_SIZE; 918 } 919 } 920} 921 922static struct nullb_page *null_radix_tree_insert(struct nullb *nullb, u64 idx, 923 struct nullb_page *t_page, bool is_cache) 924{ 925 struct radix_tree_root *root; 926 927 root = is_cache ? &nullb->dev->cache : &nullb->dev->data; 928 929 if (radix_tree_insert(root, idx, t_page)) { 930 null_free_page(t_page); 931 t_page = radix_tree_lookup(root, idx); 932 WARN_ON(!t_page || t_page->page->index != idx); 933 } else if (is_cache) 934 nullb->dev->curr_cache += PAGE_SIZE; 935 936 return t_page; 937} 938 939static void null_free_device_storage(struct nullb_device *dev, bool is_cache) 940{ 941 unsigned long pos = 0; 942 int nr_pages; 943 struct nullb_page *ret, *t_pages[FREE_BATCH]; 944 struct radix_tree_root *root; 945 946 root = is_cache ? &dev->cache : &dev->data; 947 948 do { 949 int i; 950 951 nr_pages = radix_tree_gang_lookup(root, 952 (void **)t_pages, pos, FREE_BATCH); 953 954 for (i = 0; i < nr_pages; i++) { 955 pos = t_pages[i]->page->index; 956 ret = radix_tree_delete_item(root, pos, t_pages[i]); 957 WARN_ON(ret != t_pages[i]); 958 null_free_page(ret); 959 } 960 961 pos++; 962 } while (nr_pages == FREE_BATCH); 963 964 if (is_cache) 965 dev->curr_cache = 0; 966} 967 968static struct nullb_page *__null_lookup_page(struct nullb *nullb, 969 sector_t sector, bool for_write, bool is_cache) 970{ 971 unsigned int sector_bit; 972 u64 idx; 973 struct nullb_page *t_page; 974 struct radix_tree_root *root; 975 976 idx = sector >> PAGE_SECTORS_SHIFT; 977 sector_bit = (sector & SECTOR_MASK); 978 979 root = is_cache ? &nullb->dev->cache : &nullb->dev->data; 980 t_page = radix_tree_lookup(root, idx); 981 WARN_ON(t_page && t_page->page->index != idx); 982 983 if (t_page && (for_write || test_bit(sector_bit, t_page->bitmap))) 984 return t_page; 985 986 return NULL; 987} 988 989static struct nullb_page *null_lookup_page(struct nullb *nullb, 990 sector_t sector, bool for_write, bool ignore_cache) 991{ 992 struct nullb_page *page = NULL; 993 994 if (!ignore_cache) 995 page = __null_lookup_page(nullb, sector, for_write, true); 996 if (page) 997 return page; 998 return __null_lookup_page(nullb, sector, for_write, false); 999} 1000 1001static struct nullb_page *null_insert_page(struct nullb *nullb, 1002 sector_t sector, bool ignore_cache) 1003 __releases(&nullb->lock) 1004 __acquires(&nullb->lock) 1005{ 1006 u64 idx; 1007 struct nullb_page *t_page; 1008 1009 t_page = null_lookup_page(nullb, sector, true, ignore_cache); 1010 if (t_page) 1011 return t_page; 1012 1013 spin_unlock_irq(&nullb->lock); 1014 1015 t_page = null_alloc_page(); 1016 if (!t_page) 1017 goto out_lock; 1018 1019 if (radix_tree_preload(GFP_NOIO)) 1020 goto out_freepage; 1021 1022 spin_lock_irq(&nullb->lock); 1023 idx = sector >> PAGE_SECTORS_SHIFT; 1024 t_page->page->index = idx; 1025 t_page = null_radix_tree_insert(nullb, idx, t_page, !ignore_cache); 1026 radix_tree_preload_end(); 1027 1028 return t_page; 1029out_freepage: 1030 null_free_page(t_page); 1031out_lock: 1032 spin_lock_irq(&nullb->lock); 1033 return null_lookup_page(nullb, sector, true, ignore_cache); 1034} 1035 1036static int null_flush_cache_page(struct nullb *nullb, struct nullb_page *c_page) 1037{ 1038 int i; 1039 unsigned int offset; 1040 u64 idx; 1041 struct nullb_page *t_page, *ret; 1042 void *dst, *src; 1043 1044 idx = c_page->page->index; 1045 1046 t_page = null_insert_page(nullb, idx << PAGE_SECTORS_SHIFT, true); 1047 1048 __clear_bit(NULLB_PAGE_LOCK, c_page->bitmap); 1049 if (test_bit(NULLB_PAGE_FREE, c_page->bitmap)) { 1050 null_free_page(c_page); 1051 if (t_page && null_page_empty(t_page)) { 1052 ret = radix_tree_delete_item(&nullb->dev->data, 1053 idx, t_page); 1054 null_free_page(t_page); 1055 } 1056 return 0; 1057 } 1058 1059 if (!t_page) 1060 return -ENOMEM; 1061 1062 src = kmap_local_page(c_page->page); 1063 dst = kmap_local_page(t_page->page); 1064 1065 for (i = 0; i < PAGE_SECTORS; 1066 i += (nullb->dev->blocksize >> SECTOR_SHIFT)) { 1067 if (test_bit(i, c_page->bitmap)) { 1068 offset = (i << SECTOR_SHIFT); 1069 memcpy(dst + offset, src + offset, 1070 nullb->dev->blocksize); 1071 __set_bit(i, t_page->bitmap); 1072 } 1073 } 1074 1075 kunmap_local(dst); 1076 kunmap_local(src); 1077 1078 ret = radix_tree_delete_item(&nullb->dev->cache, idx, c_page); 1079 null_free_page(ret); 1080 nullb->dev->curr_cache -= PAGE_SIZE; 1081 1082 return 0; 1083} 1084 1085static int null_make_cache_space(struct nullb *nullb, unsigned long n) 1086{ 1087 int i, err, nr_pages; 1088 struct nullb_page *c_pages[FREE_BATCH]; 1089 unsigned long flushed = 0, one_round; 1090 1091again: 1092 if ((nullb->dev->cache_size * 1024 * 1024) > 1093 nullb->dev->curr_cache + n || nullb->dev->curr_cache == 0) 1094 return 0; 1095 1096 nr_pages = radix_tree_gang_lookup(&nullb->dev->cache, 1097 (void **)c_pages, nullb->cache_flush_pos, FREE_BATCH); 1098 /* 1099 * nullb_flush_cache_page could unlock before using the c_pages. To 1100 * avoid race, we don't allow page free 1101 */ 1102 for (i = 0; i < nr_pages; i++) { 1103 nullb->cache_flush_pos = c_pages[i]->page->index; 1104 /* 1105 * We found the page which is being flushed to disk by other 1106 * threads 1107 */ 1108 if (test_bit(NULLB_PAGE_LOCK, c_pages[i]->bitmap)) 1109 c_pages[i] = NULL; 1110 else 1111 __set_bit(NULLB_PAGE_LOCK, c_pages[i]->bitmap); 1112 } 1113 1114 one_round = 0; 1115 for (i = 0; i < nr_pages; i++) { 1116 if (c_pages[i] == NULL) 1117 continue; 1118 err = null_flush_cache_page(nullb, c_pages[i]); 1119 if (err) 1120 return err; 1121 one_round++; 1122 } 1123 flushed += one_round << PAGE_SHIFT; 1124 1125 if (n > flushed) { 1126 if (nr_pages == 0) 1127 nullb->cache_flush_pos = 0; 1128 if (one_round == 0) { 1129 /* give other threads a chance */ 1130 spin_unlock_irq(&nullb->lock); 1131 spin_lock_irq(&nullb->lock); 1132 } 1133 goto again; 1134 } 1135 return 0; 1136} 1137 1138static int copy_to_nullb(struct nullb *nullb, struct page *source, 1139 unsigned int off, sector_t sector, size_t n, bool is_fua) 1140{ 1141 size_t temp, count = 0; 1142 unsigned int offset; 1143 struct nullb_page *t_page; 1144 1145 while (count < n) { 1146 temp = min_t(size_t, nullb->dev->blocksize, n - count); 1147 1148 if (null_cache_active(nullb) && !is_fua) 1149 null_make_cache_space(nullb, PAGE_SIZE); 1150 1151 offset = (sector & SECTOR_MASK) << SECTOR_SHIFT; 1152 t_page = null_insert_page(nullb, sector, 1153 !null_cache_active(nullb) || is_fua); 1154 if (!t_page) 1155 return -ENOSPC; 1156 1157 memcpy_page(t_page->page, offset, source, off + count, temp); 1158 1159 __set_bit(sector & SECTOR_MASK, t_page->bitmap); 1160 1161 if (is_fua) 1162 null_free_sector(nullb, sector, true); 1163 1164 count += temp; 1165 sector += temp >> SECTOR_SHIFT; 1166 } 1167 return 0; 1168} 1169 1170static int copy_from_nullb(struct nullb *nullb, struct page *dest, 1171 unsigned int off, sector_t sector, size_t n) 1172{ 1173 size_t temp, count = 0; 1174 unsigned int offset; 1175 struct nullb_page *t_page; 1176 1177 while (count < n) { 1178 temp = min_t(size_t, nullb->dev->blocksize, n - count); 1179 1180 offset = (sector & SECTOR_MASK) << SECTOR_SHIFT; 1181 t_page = null_lookup_page(nullb, sector, false, 1182 !null_cache_active(nullb)); 1183 1184 if (t_page) 1185 memcpy_page(dest, off + count, t_page->page, offset, 1186 temp); 1187 else 1188 zero_user(dest, off + count, temp); 1189 1190 count += temp; 1191 sector += temp >> SECTOR_SHIFT; 1192 } 1193 return 0; 1194} 1195 1196static void nullb_fill_pattern(struct nullb *nullb, struct page *page, 1197 unsigned int len, unsigned int off) 1198{ 1199 memset_page(page, off, 0xff, len); 1200} 1201 1202blk_status_t null_handle_discard(struct nullb_device *dev, 1203 sector_t sector, sector_t nr_sectors) 1204{ 1205 struct nullb *nullb = dev->nullb; 1206 size_t n = nr_sectors << SECTOR_SHIFT; 1207 size_t temp; 1208 1209 spin_lock_irq(&nullb->lock); 1210 while (n > 0) { 1211 temp = min_t(size_t, n, dev->blocksize); 1212 null_free_sector(nullb, sector, false); 1213 if (null_cache_active(nullb)) 1214 null_free_sector(nullb, sector, true); 1215 sector += temp >> SECTOR_SHIFT; 1216 n -= temp; 1217 } 1218 spin_unlock_irq(&nullb->lock); 1219 1220 return BLK_STS_OK; 1221} 1222 1223static int null_handle_flush(struct nullb *nullb) 1224{ 1225 int err; 1226 1227 if (!null_cache_active(nullb)) 1228 return 0; 1229 1230 spin_lock_irq(&nullb->lock); 1231 while (true) { 1232 err = null_make_cache_space(nullb, 1233 nullb->dev->cache_size * 1024 * 1024); 1234 if (err || nullb->dev->curr_cache == 0) 1235 break; 1236 } 1237 1238 WARN_ON(!radix_tree_empty(&nullb->dev->cache)); 1239 spin_unlock_irq(&nullb->lock); 1240 return err; 1241} 1242 1243static int null_transfer(struct nullb *nullb, struct page *page, 1244 unsigned int len, unsigned int off, bool is_write, sector_t sector, 1245 bool is_fua) 1246{ 1247 struct nullb_device *dev = nullb->dev; 1248 unsigned int valid_len = len; 1249 int err = 0; 1250 1251 if (!is_write) { 1252 if (dev->zoned) 1253 valid_len = null_zone_valid_read_len(nullb, 1254 sector, len); 1255 1256 if (valid_len) { 1257 err = copy_from_nullb(nullb, page, off, 1258 sector, valid_len); 1259 off += valid_len; 1260 len -= valid_len; 1261 } 1262 1263 if (len) 1264 nullb_fill_pattern(nullb, page, len, off); 1265 flush_dcache_page(page); 1266 } else { 1267 flush_dcache_page(page); 1268 err = copy_to_nullb(nullb, page, off, sector, len, is_fua); 1269 } 1270 1271 return err; 1272} 1273 1274static int null_handle_rq(struct nullb_cmd *cmd) 1275{ 1276 struct request *rq = cmd->rq; 1277 struct nullb *nullb = cmd->nq->dev->nullb; 1278 int err; 1279 unsigned int len; 1280 sector_t sector = blk_rq_pos(rq); 1281 struct req_iterator iter; 1282 struct bio_vec bvec; 1283 1284 spin_lock_irq(&nullb->lock); 1285 rq_for_each_segment(bvec, rq, iter) { 1286 len = bvec.bv_len; 1287 err = null_transfer(nullb, bvec.bv_page, len, bvec.bv_offset, 1288 op_is_write(req_op(rq)), sector, 1289 rq->cmd_flags & REQ_FUA); 1290 if (err) { 1291 spin_unlock_irq(&nullb->lock); 1292 return err; 1293 } 1294 sector += len >> SECTOR_SHIFT; 1295 } 1296 spin_unlock_irq(&nullb->lock); 1297 1298 return 0; 1299} 1300 1301static int null_handle_bio(struct nullb_cmd *cmd) 1302{ 1303 struct bio *bio = cmd->bio; 1304 struct nullb *nullb = cmd->nq->dev->nullb; 1305 int err; 1306 unsigned int len; 1307 sector_t sector = bio->bi_iter.bi_sector; 1308 struct bio_vec bvec; 1309 struct bvec_iter iter; 1310 1311 spin_lock_irq(&nullb->lock); 1312 bio_for_each_segment(bvec, bio, iter) { 1313 len = bvec.bv_len; 1314 err = null_transfer(nullb, bvec.bv_page, len, bvec.bv_offset, 1315 op_is_write(bio_op(bio)), sector, 1316 bio->bi_opf & REQ_FUA); 1317 if (err) { 1318 spin_unlock_irq(&nullb->lock); 1319 return err; 1320 } 1321 sector += len >> SECTOR_SHIFT; 1322 } 1323 spin_unlock_irq(&nullb->lock); 1324 return 0; 1325} 1326 1327static void null_stop_queue(struct nullb *nullb) 1328{ 1329 struct request_queue *q = nullb->q; 1330 1331 if (nullb->dev->queue_mode == NULL_Q_MQ) 1332 blk_mq_stop_hw_queues(q); 1333} 1334 1335static void null_restart_queue_async(struct nullb *nullb) 1336{ 1337 struct request_queue *q = nullb->q; 1338 1339 if (nullb->dev->queue_mode == NULL_Q_MQ) 1340 blk_mq_start_stopped_hw_queues(q, true); 1341} 1342 1343static inline blk_status_t null_handle_throttled(struct nullb_cmd *cmd) 1344{ 1345 struct nullb_device *dev = cmd->nq->dev; 1346 struct nullb *nullb = dev->nullb; 1347 blk_status_t sts = BLK_STS_OK; 1348 struct request *rq = cmd->rq; 1349 1350 if (!hrtimer_active(&nullb->bw_timer)) 1351 hrtimer_restart(&nullb->bw_timer); 1352 1353 if (atomic_long_sub_return(blk_rq_bytes(rq), &nullb->cur_bytes) < 0) { 1354 null_stop_queue(nullb); 1355 /* race with timer */ 1356 if (atomic_long_read(&nullb->cur_bytes) > 0) 1357 null_restart_queue_async(nullb); 1358 /* requeue request */ 1359 sts = BLK_STS_DEV_RESOURCE; 1360 } 1361 return sts; 1362} 1363 1364static inline blk_status_t null_handle_badblocks(struct nullb_cmd *cmd, 1365 sector_t sector, 1366 sector_t nr_sectors) 1367{ 1368 struct badblocks *bb = &cmd->nq->dev->badblocks; 1369 sector_t first_bad; 1370 int bad_sectors; 1371 1372 if (badblocks_check(bb, sector, nr_sectors, &first_bad, &bad_sectors)) 1373 return BLK_STS_IOERR; 1374 1375 return BLK_STS_OK; 1376} 1377 1378static inline blk_status_t null_handle_memory_backed(struct nullb_cmd *cmd, 1379 enum req_op op, 1380 sector_t sector, 1381 sector_t nr_sectors) 1382{ 1383 struct nullb_device *dev = cmd->nq->dev; 1384 int err; 1385 1386 if (op == REQ_OP_DISCARD) 1387 return null_handle_discard(dev, sector, nr_sectors); 1388 1389 if (dev->queue_mode == NULL_Q_BIO) 1390 err = null_handle_bio(cmd); 1391 else 1392 err = null_handle_rq(cmd); 1393 1394 return errno_to_blk_status(err); 1395} 1396 1397static void nullb_zero_read_cmd_buffer(struct nullb_cmd *cmd) 1398{ 1399 struct nullb_device *dev = cmd->nq->dev; 1400 struct bio *bio; 1401 1402 if (dev->memory_backed) 1403 return; 1404 1405 if (dev->queue_mode == NULL_Q_BIO && bio_op(cmd->bio) == REQ_OP_READ) { 1406 zero_fill_bio(cmd->bio); 1407 } else if (req_op(cmd->rq) == REQ_OP_READ) { 1408 __rq_for_each_bio(bio, cmd->rq) 1409 zero_fill_bio(bio); 1410 } 1411} 1412 1413static inline void nullb_complete_cmd(struct nullb_cmd *cmd) 1414{ 1415 /* 1416 * Since root privileges are required to configure the null_blk 1417 * driver, it is fine that this driver does not initialize the 1418 * data buffers of read commands. Zero-initialize these buffers 1419 * anyway if KMSAN is enabled to prevent that KMSAN complains 1420 * about null_blk not initializing read data buffers. 1421 */ 1422 if (IS_ENABLED(CONFIG_KMSAN)) 1423 nullb_zero_read_cmd_buffer(cmd); 1424 1425 /* Complete IO by inline, softirq or timer */ 1426 switch (cmd->nq->dev->irqmode) { 1427 case NULL_IRQ_SOFTIRQ: 1428 switch (cmd->nq->dev->queue_mode) { 1429 case NULL_Q_MQ: 1430 blk_mq_complete_request(cmd->rq); 1431 break; 1432 case NULL_Q_BIO: 1433 /* 1434 * XXX: no proper submitting cpu information available. 1435 */ 1436 end_cmd(cmd); 1437 break; 1438 } 1439 break; 1440 case NULL_IRQ_NONE: 1441 end_cmd(cmd); 1442 break; 1443 case NULL_IRQ_TIMER: 1444 null_cmd_end_timer(cmd); 1445 break; 1446 } 1447} 1448 1449blk_status_t null_process_cmd(struct nullb_cmd *cmd, enum req_op op, 1450 sector_t sector, unsigned int nr_sectors) 1451{ 1452 struct nullb_device *dev = cmd->nq->dev; 1453 blk_status_t ret; 1454 1455 if (dev->badblocks.shift != -1) { 1456 ret = null_handle_badblocks(cmd, sector, nr_sectors); 1457 if (ret != BLK_STS_OK) 1458 return ret; 1459 } 1460 1461 if (dev->memory_backed) 1462 return null_handle_memory_backed(cmd, op, sector, nr_sectors); 1463 1464 return BLK_STS_OK; 1465} 1466 1467static blk_status_t null_handle_cmd(struct nullb_cmd *cmd, sector_t sector, 1468 sector_t nr_sectors, enum req_op op) 1469{ 1470 struct nullb_device *dev = cmd->nq->dev; 1471 struct nullb *nullb = dev->nullb; 1472 blk_status_t sts; 1473 1474 if (test_bit(NULLB_DEV_FL_THROTTLED, &dev->flags)) { 1475 sts = null_handle_throttled(cmd); 1476 if (sts != BLK_STS_OK) 1477 return sts; 1478 } 1479 1480 if (op == REQ_OP_FLUSH) { 1481 cmd->error = errno_to_blk_status(null_handle_flush(nullb)); 1482 goto out; 1483 } 1484 1485 if (dev->zoned) 1486 sts = null_process_zoned_cmd(cmd, op, sector, nr_sectors); 1487 else 1488 sts = null_process_cmd(cmd, op, sector, nr_sectors); 1489 1490 /* Do not overwrite errors (e.g. timeout errors) */ 1491 if (cmd->error == BLK_STS_OK) 1492 cmd->error = sts; 1493 1494out: 1495 nullb_complete_cmd(cmd); 1496 return BLK_STS_OK; 1497} 1498 1499static enum hrtimer_restart nullb_bwtimer_fn(struct hrtimer *timer) 1500{ 1501 struct nullb *nullb = container_of(timer, struct nullb, bw_timer); 1502 ktime_t timer_interval = ktime_set(0, TIMER_INTERVAL); 1503 unsigned int mbps = nullb->dev->mbps; 1504 1505 if (atomic_long_read(&nullb->cur_bytes) == mb_per_tick(mbps)) 1506 return HRTIMER_NORESTART; 1507 1508 atomic_long_set(&nullb->cur_bytes, mb_per_tick(mbps)); 1509 null_restart_queue_async(nullb); 1510 1511 hrtimer_forward_now(&nullb->bw_timer, timer_interval); 1512 1513 return HRTIMER_RESTART; 1514} 1515 1516static void nullb_setup_bwtimer(struct nullb *nullb) 1517{ 1518 ktime_t timer_interval = ktime_set(0, TIMER_INTERVAL); 1519 1520 hrtimer_init(&nullb->bw_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); 1521 nullb->bw_timer.function = nullb_bwtimer_fn; 1522 atomic_long_set(&nullb->cur_bytes, mb_per_tick(nullb->dev->mbps)); 1523 hrtimer_start(&nullb->bw_timer, timer_interval, HRTIMER_MODE_REL); 1524} 1525 1526static struct nullb_queue *nullb_to_queue(struct nullb *nullb) 1527{ 1528 int index = 0; 1529 1530 if (nullb->nr_queues != 1) 1531 index = raw_smp_processor_id() / ((nr_cpu_ids + nullb->nr_queues - 1) / nullb->nr_queues); 1532 1533 return &nullb->queues[index]; 1534} 1535 1536static void null_submit_bio(struct bio *bio) 1537{ 1538 sector_t sector = bio->bi_iter.bi_sector; 1539 sector_t nr_sectors = bio_sectors(bio); 1540 struct nullb *nullb = bio->bi_bdev->bd_disk->private_data; 1541 struct nullb_queue *nq = nullb_to_queue(nullb); 1542 1543 null_handle_cmd(alloc_cmd(nq, bio), sector, nr_sectors, bio_op(bio)); 1544} 1545 1546#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION 1547 1548static bool should_timeout_request(struct request *rq) 1549{ 1550 struct nullb_cmd *cmd = blk_mq_rq_to_pdu(rq); 1551 struct nullb_device *dev = cmd->nq->dev; 1552 1553 return should_fail(&dev->timeout_config.attr, 1); 1554} 1555 1556static bool should_requeue_request(struct request *rq) 1557{ 1558 struct nullb_cmd *cmd = blk_mq_rq_to_pdu(rq); 1559 struct nullb_device *dev = cmd->nq->dev; 1560 1561 return should_fail(&dev->requeue_config.attr, 1); 1562} 1563 1564static bool should_init_hctx_fail(struct nullb_device *dev) 1565{ 1566 return should_fail(&dev->init_hctx_fault_config.attr, 1); 1567} 1568 1569#else 1570 1571static bool should_timeout_request(struct request *rq) 1572{ 1573 return false; 1574} 1575 1576static bool should_requeue_request(struct request *rq) 1577{ 1578 return false; 1579} 1580 1581static bool should_init_hctx_fail(struct nullb_device *dev) 1582{ 1583 return false; 1584} 1585 1586#endif 1587 1588static void null_map_queues(struct blk_mq_tag_set *set) 1589{ 1590 struct nullb *nullb = set->driver_data; 1591 int i, qoff; 1592 unsigned int submit_queues = g_submit_queues; 1593 unsigned int poll_queues = g_poll_queues; 1594 1595 if (nullb) { 1596 struct nullb_device *dev = nullb->dev; 1597 1598 /* 1599 * Refer nr_hw_queues of the tag set to check if the expected 1600 * number of hardware queues are prepared. If block layer failed 1601 * to prepare them, use previous numbers of submit queues and 1602 * poll queues to map queues. 1603 */ 1604 if (set->nr_hw_queues == 1605 dev->submit_queues + dev->poll_queues) { 1606 submit_queues = dev->submit_queues; 1607 poll_queues = dev->poll_queues; 1608 } else if (set->nr_hw_queues == 1609 dev->prev_submit_queues + dev->prev_poll_queues) { 1610 submit_queues = dev->prev_submit_queues; 1611 poll_queues = dev->prev_poll_queues; 1612 } else { 1613 pr_warn("tag set has unexpected nr_hw_queues: %d\n", 1614 set->nr_hw_queues); 1615 WARN_ON_ONCE(true); 1616 submit_queues = 1; 1617 poll_queues = 0; 1618 } 1619 } 1620 1621 for (i = 0, qoff = 0; i < set->nr_maps; i++) { 1622 struct blk_mq_queue_map *map = &set->map[i]; 1623 1624 switch (i) { 1625 case HCTX_TYPE_DEFAULT: 1626 map->nr_queues = submit_queues; 1627 break; 1628 case HCTX_TYPE_READ: 1629 map->nr_queues = 0; 1630 continue; 1631 case HCTX_TYPE_POLL: 1632 map->nr_queues = poll_queues; 1633 break; 1634 } 1635 map->queue_offset = qoff; 1636 qoff += map->nr_queues; 1637 blk_mq_map_queues(map); 1638 } 1639} 1640 1641static int null_poll(struct blk_mq_hw_ctx *hctx, struct io_comp_batch *iob) 1642{ 1643 struct nullb_queue *nq = hctx->driver_data; 1644 LIST_HEAD(list); 1645 int nr = 0; 1646 struct request *rq; 1647 1648 spin_lock(&nq->poll_lock); 1649 list_splice_init(&nq->poll_list, &list); 1650 list_for_each_entry(rq, &list, queuelist) 1651 blk_mq_set_request_complete(rq); 1652 spin_unlock(&nq->poll_lock); 1653 1654 while (!list_empty(&list)) { 1655 struct nullb_cmd *cmd; 1656 struct request *req; 1657 1658 req = list_first_entry(&list, struct request, queuelist); 1659 list_del_init(&req->queuelist); 1660 cmd = blk_mq_rq_to_pdu(req); 1661 cmd->error = null_process_cmd(cmd, req_op(req), blk_rq_pos(req), 1662 blk_rq_sectors(req)); 1663 if (!blk_mq_add_to_batch(req, iob, (__force int) cmd->error, 1664 blk_mq_end_request_batch)) 1665 end_cmd(cmd); 1666 nr++; 1667 } 1668 1669 return nr; 1670} 1671 1672static enum blk_eh_timer_return null_timeout_rq(struct request *rq) 1673{ 1674 struct blk_mq_hw_ctx *hctx = rq->mq_hctx; 1675 struct nullb_cmd *cmd = blk_mq_rq_to_pdu(rq); 1676 1677 if (hctx->type == HCTX_TYPE_POLL) { 1678 struct nullb_queue *nq = hctx->driver_data; 1679 1680 spin_lock(&nq->poll_lock); 1681 /* The request may have completed meanwhile. */ 1682 if (blk_mq_request_completed(rq)) { 1683 spin_unlock(&nq->poll_lock); 1684 return BLK_EH_DONE; 1685 } 1686 list_del_init(&rq->queuelist); 1687 spin_unlock(&nq->poll_lock); 1688 } 1689 1690 pr_info("rq %p timed out\n", rq); 1691 1692 /* 1693 * If the device is marked as blocking (i.e. memory backed or zoned 1694 * device), the submission path may be blocked waiting for resources 1695 * and cause real timeouts. For these real timeouts, the submission 1696 * path will complete the request using blk_mq_complete_request(). 1697 * Only fake timeouts need to execute blk_mq_complete_request() here. 1698 */ 1699 cmd->error = BLK_STS_TIMEOUT; 1700 if (cmd->fake_timeout || hctx->type == HCTX_TYPE_POLL) 1701 blk_mq_complete_request(rq); 1702 return BLK_EH_DONE; 1703} 1704 1705static blk_status_t null_queue_rq(struct blk_mq_hw_ctx *hctx, 1706 const struct blk_mq_queue_data *bd) 1707{ 1708 struct request *rq = bd->rq; 1709 struct nullb_cmd *cmd = blk_mq_rq_to_pdu(rq); 1710 struct nullb_queue *nq = hctx->driver_data; 1711 sector_t nr_sectors = blk_rq_sectors(rq); 1712 sector_t sector = blk_rq_pos(rq); 1713 const bool is_poll = hctx->type == HCTX_TYPE_POLL; 1714 1715 might_sleep_if(hctx->flags & BLK_MQ_F_BLOCKING); 1716 1717 if (!is_poll && nq->dev->irqmode == NULL_IRQ_TIMER) { 1718 hrtimer_init(&cmd->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); 1719 cmd->timer.function = null_cmd_timer_expired; 1720 } 1721 cmd->rq = rq; 1722 cmd->error = BLK_STS_OK; 1723 cmd->nq = nq; 1724 cmd->fake_timeout = should_timeout_request(rq) || 1725 blk_should_fake_timeout(rq->q); 1726 1727 blk_mq_start_request(rq); 1728 1729 if (should_requeue_request(rq)) { 1730 /* 1731 * Alternate between hitting the core BUSY path, and the 1732 * driver driven requeue path 1733 */ 1734 nq->requeue_selection++; 1735 if (nq->requeue_selection & 1) 1736 return BLK_STS_RESOURCE; 1737 blk_mq_requeue_request(rq, true); 1738 return BLK_STS_OK; 1739 } 1740 1741 if (is_poll) { 1742 spin_lock(&nq->poll_lock); 1743 list_add_tail(&rq->queuelist, &nq->poll_list); 1744 spin_unlock(&nq->poll_lock); 1745 return BLK_STS_OK; 1746 } 1747 if (cmd->fake_timeout) 1748 return BLK_STS_OK; 1749 1750 return null_handle_cmd(cmd, sector, nr_sectors, req_op(rq)); 1751} 1752 1753static void cleanup_queue(struct nullb_queue *nq) 1754{ 1755 bitmap_free(nq->tag_map); 1756 kfree(nq->cmds); 1757} 1758 1759static void cleanup_queues(struct nullb *nullb) 1760{ 1761 int i; 1762 1763 for (i = 0; i < nullb->nr_queues; i++) 1764 cleanup_queue(&nullb->queues[i]); 1765 1766 kfree(nullb->queues); 1767} 1768 1769static void null_exit_hctx(struct blk_mq_hw_ctx *hctx, unsigned int hctx_idx) 1770{ 1771 struct nullb_queue *nq = hctx->driver_data; 1772 struct nullb *nullb = nq->dev->nullb; 1773 1774 nullb->nr_queues--; 1775} 1776 1777static void null_init_queue(struct nullb *nullb, struct nullb_queue *nq) 1778{ 1779 init_waitqueue_head(&nq->wait); 1780 nq->queue_depth = nullb->queue_depth; 1781 nq->dev = nullb->dev; 1782 INIT_LIST_HEAD(&nq->poll_list); 1783 spin_lock_init(&nq->poll_lock); 1784} 1785 1786static int null_init_hctx(struct blk_mq_hw_ctx *hctx, void *driver_data, 1787 unsigned int hctx_idx) 1788{ 1789 struct nullb *nullb = hctx->queue->queuedata; 1790 struct nullb_queue *nq; 1791 1792 if (should_init_hctx_fail(nullb->dev)) 1793 return -EFAULT; 1794 1795 nq = &nullb->queues[hctx_idx]; 1796 hctx->driver_data = nq; 1797 null_init_queue(nullb, nq); 1798 nullb->nr_queues++; 1799 1800 return 0; 1801} 1802 1803static const struct blk_mq_ops null_mq_ops = { 1804 .queue_rq = null_queue_rq, 1805 .complete = null_complete_rq, 1806 .timeout = null_timeout_rq, 1807 .poll = null_poll, 1808 .map_queues = null_map_queues, 1809 .init_hctx = null_init_hctx, 1810 .exit_hctx = null_exit_hctx, 1811}; 1812 1813static void null_del_dev(struct nullb *nullb) 1814{ 1815 struct nullb_device *dev; 1816 1817 if (!nullb) 1818 return; 1819 1820 dev = nullb->dev; 1821 1822 ida_simple_remove(&nullb_indexes, nullb->index); 1823 1824 list_del_init(&nullb->list); 1825 1826 del_gendisk(nullb->disk); 1827 1828 if (test_bit(NULLB_DEV_FL_THROTTLED, &nullb->dev->flags)) { 1829 hrtimer_cancel(&nullb->bw_timer); 1830 atomic_long_set(&nullb->cur_bytes, LONG_MAX); 1831 null_restart_queue_async(nullb); 1832 } 1833 1834 put_disk(nullb->disk); 1835 if (dev->queue_mode == NULL_Q_MQ && 1836 nullb->tag_set == &nullb->__tag_set) 1837 blk_mq_free_tag_set(nullb->tag_set); 1838 cleanup_queues(nullb); 1839 if (null_cache_active(nullb)) 1840 null_free_device_storage(nullb->dev, true); 1841 kfree(nullb); 1842 dev->nullb = NULL; 1843} 1844 1845static void null_config_discard(struct nullb *nullb) 1846{ 1847 if (nullb->dev->discard == false) 1848 return; 1849 1850 if (!nullb->dev->memory_backed) { 1851 nullb->dev->discard = false; 1852 pr_info("discard option is ignored without memory backing\n"); 1853 return; 1854 } 1855 1856 if (nullb->dev->zoned) { 1857 nullb->dev->discard = false; 1858 pr_info("discard option is ignored in zoned mode\n"); 1859 return; 1860 } 1861 1862 nullb->q->limits.discard_granularity = nullb->dev->blocksize; 1863 blk_queue_max_discard_sectors(nullb->q, UINT_MAX >> 9); 1864} 1865 1866static const struct block_device_operations null_bio_ops = { 1867 .owner = THIS_MODULE, 1868 .submit_bio = null_submit_bio, 1869 .report_zones = null_report_zones, 1870}; 1871 1872static const struct block_device_operations null_rq_ops = { 1873 .owner = THIS_MODULE, 1874 .report_zones = null_report_zones, 1875}; 1876 1877static int setup_commands(struct nullb_queue *nq) 1878{ 1879 struct nullb_cmd *cmd; 1880 int i; 1881 1882 nq->cmds = kcalloc(nq->queue_depth, sizeof(*cmd), GFP_KERNEL); 1883 if (!nq->cmds) 1884 return -ENOMEM; 1885 1886 nq->tag_map = bitmap_zalloc(nq->queue_depth, GFP_KERNEL); 1887 if (!nq->tag_map) { 1888 kfree(nq->cmds); 1889 return -ENOMEM; 1890 } 1891 1892 for (i = 0; i < nq->queue_depth; i++) { 1893 cmd = &nq->cmds[i]; 1894 cmd->tag = -1U; 1895 } 1896 1897 return 0; 1898} 1899 1900static int setup_queues(struct nullb *nullb) 1901{ 1902 int nqueues = nr_cpu_ids; 1903 1904 if (g_poll_queues) 1905 nqueues += g_poll_queues; 1906 1907 nullb->queues = kcalloc(nqueues, sizeof(struct nullb_queue), 1908 GFP_KERNEL); 1909 if (!nullb->queues) 1910 return -ENOMEM; 1911 1912 nullb->queue_depth = nullb->dev->hw_queue_depth; 1913 return 0; 1914} 1915 1916static int init_driver_queues(struct nullb *nullb) 1917{ 1918 struct nullb_queue *nq; 1919 int i, ret = 0; 1920 1921 for (i = 0; i < nullb->dev->submit_queues; i++) { 1922 nq = &nullb->queues[i]; 1923 1924 null_init_queue(nullb, nq); 1925 1926 ret = setup_commands(nq); 1927 if (ret) 1928 return ret; 1929 nullb->nr_queues++; 1930 } 1931 return 0; 1932} 1933 1934static int null_gendisk_register(struct nullb *nullb) 1935{ 1936 sector_t size = ((sector_t)nullb->dev->size * SZ_1M) >> SECTOR_SHIFT; 1937 struct gendisk *disk = nullb->disk; 1938 1939 set_capacity(disk, size); 1940 1941 disk->major = null_major; 1942 disk->first_minor = nullb->index; 1943 disk->minors = 1; 1944 if (queue_is_mq(nullb->q)) 1945 disk->fops = &null_rq_ops; 1946 else 1947 disk->fops = &null_bio_ops; 1948 disk->private_data = nullb; 1949 strncpy(disk->disk_name, nullb->disk_name, DISK_NAME_LEN); 1950 1951 if (nullb->dev->zoned) { 1952 int ret = null_register_zoned_dev(nullb); 1953 1954 if (ret) 1955 return ret; 1956 } 1957 1958 return add_disk(disk); 1959} 1960 1961static int null_init_tag_set(struct nullb *nullb, struct blk_mq_tag_set *set) 1962{ 1963 unsigned int flags = BLK_MQ_F_SHOULD_MERGE; 1964 int hw_queues, numa_node; 1965 unsigned int queue_depth; 1966 int poll_queues; 1967 1968 if (nullb) { 1969 hw_queues = nullb->dev->submit_queues; 1970 poll_queues = nullb->dev->poll_queues; 1971 queue_depth = nullb->dev->hw_queue_depth; 1972 numa_node = nullb->dev->home_node; 1973 if (nullb->dev->no_sched) 1974 flags |= BLK_MQ_F_NO_SCHED; 1975 if (nullb->dev->shared_tag_bitmap) 1976 flags |= BLK_MQ_F_TAG_HCTX_SHARED; 1977 if (nullb->dev->blocking) 1978 flags |= BLK_MQ_F_BLOCKING; 1979 } else { 1980 hw_queues = g_submit_queues; 1981 poll_queues = g_poll_queues; 1982 queue_depth = g_hw_queue_depth; 1983 numa_node = g_home_node; 1984 if (g_no_sched) 1985 flags |= BLK_MQ_F_NO_SCHED; 1986 if (g_shared_tag_bitmap) 1987 flags |= BLK_MQ_F_TAG_HCTX_SHARED; 1988 if (g_blocking) 1989 flags |= BLK_MQ_F_BLOCKING; 1990 } 1991 1992 set->ops = &null_mq_ops; 1993 set->cmd_size = sizeof(struct nullb_cmd); 1994 set->flags = flags; 1995 set->driver_data = nullb; 1996 set->nr_hw_queues = hw_queues; 1997 set->queue_depth = queue_depth; 1998 set->numa_node = numa_node; 1999 if (poll_queues) { 2000 set->nr_hw_queues += poll_queues; 2001 set->nr_maps = 3; 2002 } else { 2003 set->nr_maps = 1; 2004 } 2005 2006 return blk_mq_alloc_tag_set(set); 2007} 2008 2009static int null_validate_conf(struct nullb_device *dev) 2010{ 2011 if (dev->queue_mode == NULL_Q_RQ) { 2012 pr_err("legacy IO path is no longer available\n"); 2013 return -EINVAL; 2014 } 2015 2016 dev->blocksize = round_down(dev->blocksize, 512); 2017 dev->blocksize = clamp_t(unsigned int, dev->blocksize, 512, 4096); 2018 2019 if (dev->queue_mode == NULL_Q_MQ && dev->use_per_node_hctx) { 2020 if (dev->submit_queues != nr_online_nodes) 2021 dev->submit_queues = nr_online_nodes; 2022 } else if (dev->submit_queues > nr_cpu_ids) 2023 dev->submit_queues = nr_cpu_ids; 2024 else if (dev->submit_queues == 0) 2025 dev->submit_queues = 1; 2026 dev->prev_submit_queues = dev->submit_queues; 2027 2028 if (dev->poll_queues > g_poll_queues) 2029 dev->poll_queues = g_poll_queues; 2030 dev->prev_poll_queues = dev->poll_queues; 2031 2032 dev->queue_mode = min_t(unsigned int, dev->queue_mode, NULL_Q_MQ); 2033 dev->irqmode = min_t(unsigned int, dev->irqmode, NULL_IRQ_TIMER); 2034 2035 /* Do memory allocation, so set blocking */ 2036 if (dev->memory_backed) 2037 dev->blocking = true; 2038 else /* cache is meaningless */ 2039 dev->cache_size = 0; 2040 dev->cache_size = min_t(unsigned long, ULONG_MAX / 1024 / 1024, 2041 dev->cache_size); 2042 dev->mbps = min_t(unsigned int, 1024 * 40, dev->mbps); 2043 /* can not stop a queue */ 2044 if (dev->queue_mode == NULL_Q_BIO) 2045 dev->mbps = 0; 2046 2047 if (dev->zoned && 2048 (!dev->zone_size || !is_power_of_2(dev->zone_size))) { 2049 pr_err("zone_size must be power-of-two\n"); 2050 return -EINVAL; 2051 } 2052 2053 return 0; 2054} 2055 2056#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION 2057static bool __null_setup_fault(struct fault_attr *attr, char *str) 2058{ 2059 if (!str[0]) 2060 return true; 2061 2062 if (!setup_fault_attr(attr, str)) 2063 return false; 2064 2065 attr->verbose = 0; 2066 return true; 2067} 2068#endif 2069 2070static bool null_setup_fault(void) 2071{ 2072#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION 2073 if (!__null_setup_fault(&null_timeout_attr, g_timeout_str)) 2074 return false; 2075 if (!__null_setup_fault(&null_requeue_attr, g_requeue_str)) 2076 return false; 2077 if (!__null_setup_fault(&null_init_hctx_attr, g_init_hctx_str)) 2078 return false; 2079#endif 2080 return true; 2081} 2082 2083static int null_add_dev(struct nullb_device *dev) 2084{ 2085 struct nullb *nullb; 2086 int rv; 2087 2088 rv = null_validate_conf(dev); 2089 if (rv) 2090 return rv; 2091 2092 nullb = kzalloc_node(sizeof(*nullb), GFP_KERNEL, dev->home_node); 2093 if (!nullb) { 2094 rv = -ENOMEM; 2095 goto out; 2096 } 2097 nullb->dev = dev; 2098 dev->nullb = nullb; 2099 2100 spin_lock_init(&nullb->lock); 2101 2102 rv = setup_queues(nullb); 2103 if (rv) 2104 goto out_free_nullb; 2105 2106 if (dev->queue_mode == NULL_Q_MQ) { 2107 if (shared_tags) { 2108 nullb->tag_set = &tag_set; 2109 rv = 0; 2110 } else { 2111 nullb->tag_set = &nullb->__tag_set; 2112 rv = null_init_tag_set(nullb, nullb->tag_set); 2113 } 2114 2115 if (rv) 2116 goto out_cleanup_queues; 2117 2118 nullb->tag_set->timeout = 5 * HZ; 2119 nullb->disk = blk_mq_alloc_disk(nullb->tag_set, nullb); 2120 if (IS_ERR(nullb->disk)) { 2121 rv = PTR_ERR(nullb->disk); 2122 goto out_cleanup_tags; 2123 } 2124 nullb->q = nullb->disk->queue; 2125 } else if (dev->queue_mode == NULL_Q_BIO) { 2126 rv = -ENOMEM; 2127 nullb->disk = blk_alloc_disk(nullb->dev->home_node); 2128 if (!nullb->disk) 2129 goto out_cleanup_queues; 2130 2131 nullb->q = nullb->disk->queue; 2132 rv = init_driver_queues(nullb); 2133 if (rv) 2134 goto out_cleanup_disk; 2135 } 2136 2137 if (dev->mbps) { 2138 set_bit(NULLB_DEV_FL_THROTTLED, &dev->flags); 2139 nullb_setup_bwtimer(nullb); 2140 } 2141 2142 if (dev->cache_size > 0) { 2143 set_bit(NULLB_DEV_FL_CACHE, &nullb->dev->flags); 2144 blk_queue_write_cache(nullb->q, true, true); 2145 } 2146 2147 if (dev->zoned) { 2148 rv = null_init_zoned_dev(dev, nullb->q); 2149 if (rv) 2150 goto out_cleanup_disk; 2151 } 2152 2153 nullb->q->queuedata = nullb; 2154 blk_queue_flag_set(QUEUE_FLAG_NONROT, nullb->q); 2155 2156 mutex_lock(&lock); 2157 rv = ida_simple_get(&nullb_indexes, 0, 0, GFP_KERNEL); 2158 if (rv < 0) { 2159 mutex_unlock(&lock); 2160 goto out_cleanup_zone; 2161 } 2162 nullb->index = rv; 2163 dev->index = rv; 2164 mutex_unlock(&lock); 2165 2166 blk_queue_logical_block_size(nullb->q, dev->blocksize); 2167 blk_queue_physical_block_size(nullb->q, dev->blocksize); 2168 if (dev->max_sectors) 2169 blk_queue_max_hw_sectors(nullb->q, dev->max_sectors); 2170 2171 if (dev->virt_boundary) 2172 blk_queue_virt_boundary(nullb->q, PAGE_SIZE - 1); 2173 2174 null_config_discard(nullb); 2175 2176 if (config_item_name(&dev->group.cg_item)) { 2177 /* Use configfs dir name as the device name */ 2178 snprintf(nullb->disk_name, sizeof(nullb->disk_name), 2179 "%s", config_item_name(&dev->group.cg_item)); 2180 } else { 2181 sprintf(nullb->disk_name, "nullb%d", nullb->index); 2182 } 2183 2184 rv = null_gendisk_register(nullb); 2185 if (rv) 2186 goto out_ida_free; 2187 2188 mutex_lock(&lock); 2189 list_add_tail(&nullb->list, &nullb_list); 2190 mutex_unlock(&lock); 2191 2192 pr_info("disk %s created\n", nullb->disk_name); 2193 2194 return 0; 2195 2196out_ida_free: 2197 ida_free(&nullb_indexes, nullb->index); 2198out_cleanup_zone: 2199 null_free_zoned_dev(dev); 2200out_cleanup_disk: 2201 put_disk(nullb->disk); 2202out_cleanup_tags: 2203 if (dev->queue_mode == NULL_Q_MQ && nullb->tag_set == &nullb->__tag_set) 2204 blk_mq_free_tag_set(nullb->tag_set); 2205out_cleanup_queues: 2206 cleanup_queues(nullb); 2207out_free_nullb: 2208 kfree(nullb); 2209 dev->nullb = NULL; 2210out: 2211 return rv; 2212} 2213 2214static struct nullb *null_find_dev_by_name(const char *name) 2215{ 2216 struct nullb *nullb = NULL, *nb; 2217 2218 mutex_lock(&lock); 2219 list_for_each_entry(nb, &nullb_list, list) { 2220 if (strcmp(nb->disk_name, name) == 0) { 2221 nullb = nb; 2222 break; 2223 } 2224 } 2225 mutex_unlock(&lock); 2226 2227 return nullb; 2228} 2229 2230static int null_create_dev(void) 2231{ 2232 struct nullb_device *dev; 2233 int ret; 2234 2235 dev = null_alloc_dev(); 2236 if (!dev) 2237 return -ENOMEM; 2238 2239 ret = null_add_dev(dev); 2240 if (ret) { 2241 null_free_dev(dev); 2242 return ret; 2243 } 2244 2245 return 0; 2246} 2247 2248static void null_destroy_dev(struct nullb *nullb) 2249{ 2250 struct nullb_device *dev = nullb->dev; 2251 2252 null_del_dev(nullb); 2253 null_free_device_storage(dev, false); 2254 null_free_dev(dev); 2255} 2256 2257static int __init null_init(void) 2258{ 2259 int ret = 0; 2260 unsigned int i; 2261 struct nullb *nullb; 2262 2263 if (g_bs > PAGE_SIZE) { 2264 pr_warn("invalid block size\n"); 2265 pr_warn("defaults block size to %lu\n", PAGE_SIZE); 2266 g_bs = PAGE_SIZE; 2267 } 2268 2269 if (g_home_node != NUMA_NO_NODE && g_home_node >= nr_online_nodes) { 2270 pr_err("invalid home_node value\n"); 2271 g_home_node = NUMA_NO_NODE; 2272 } 2273 2274 if (!null_setup_fault()) 2275 return -EINVAL; 2276 2277 if (g_queue_mode == NULL_Q_RQ) { 2278 pr_err("legacy IO path is no longer available\n"); 2279 return -EINVAL; 2280 } 2281 2282 if (g_queue_mode == NULL_Q_MQ && g_use_per_node_hctx) { 2283 if (g_submit_queues != nr_online_nodes) { 2284 pr_warn("submit_queues param is set to %u.\n", 2285 nr_online_nodes); 2286 g_submit_queues = nr_online_nodes; 2287 } 2288 } else if (g_submit_queues > nr_cpu_ids) { 2289 g_submit_queues = nr_cpu_ids; 2290 } else if (g_submit_queues <= 0) { 2291 g_submit_queues = 1; 2292 } 2293 2294 if (g_queue_mode == NULL_Q_MQ && shared_tags) { 2295 ret = null_init_tag_set(NULL, &tag_set); 2296 if (ret) 2297 return ret; 2298 } 2299 2300 config_group_init(&nullb_subsys.su_group); 2301 mutex_init(&nullb_subsys.su_mutex); 2302 2303 ret = configfs_register_subsystem(&nullb_subsys); 2304 if (ret) 2305 goto err_tagset; 2306 2307 mutex_init(&lock); 2308 2309 null_major = register_blkdev(0, "nullb"); 2310 if (null_major < 0) { 2311 ret = null_major; 2312 goto err_conf; 2313 } 2314 2315 for (i = 0; i < nr_devices; i++) { 2316 ret = null_create_dev(); 2317 if (ret) 2318 goto err_dev; 2319 } 2320 2321 pr_info("module loaded\n"); 2322 return 0; 2323 2324err_dev: 2325 while (!list_empty(&nullb_list)) { 2326 nullb = list_entry(nullb_list.next, struct nullb, list); 2327 null_destroy_dev(nullb); 2328 } 2329 unregister_blkdev(null_major, "nullb"); 2330err_conf: 2331 configfs_unregister_subsystem(&nullb_subsys); 2332err_tagset: 2333 if (g_queue_mode == NULL_Q_MQ && shared_tags) 2334 blk_mq_free_tag_set(&tag_set); 2335 return ret; 2336} 2337 2338static void __exit null_exit(void) 2339{ 2340 struct nullb *nullb; 2341 2342 configfs_unregister_subsystem(&nullb_subsys); 2343 2344 unregister_blkdev(null_major, "nullb"); 2345 2346 mutex_lock(&lock); 2347 while (!list_empty(&nullb_list)) { 2348 nullb = list_entry(nullb_list.next, struct nullb, list); 2349 null_destroy_dev(nullb); 2350 } 2351 mutex_unlock(&lock); 2352 2353 if (g_queue_mode == NULL_Q_MQ && shared_tags) 2354 blk_mq_free_tag_set(&tag_set); 2355} 2356 2357module_init(null_init); 2358module_exit(null_exit); 2359 2360MODULE_AUTHOR("Jens Axboe <axboe@kernel.dk>"); 2361MODULE_LICENSE("GPL"); 2362