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