drivers/block/null_blk/main.c

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