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