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