This source file includes following definitions.
- mb_per_tick
- null_param_store_val
- null_set_queue_mode
- null_set_irqmode
- to_nullb_device
- nullb_device_uint_attr_show
- nullb_device_ulong_attr_show
- nullb_device_bool_attr_show
- nullb_device_uint_attr_store
- nullb_device_ulong_attr_store
- nullb_device_bool_attr_store
- nullb_device_power_show
- nullb_device_power_store
- nullb_device_badblocks_show
- nullb_device_badblocks_store
- nullb_device_release
- nullb_group_make_item
- nullb_group_drop_item
- memb_group_features_show
- null_cache_active
- null_alloc_dev
- null_free_dev
- put_tag
- get_tag
- free_cmd
- __alloc_cmd
- alloc_cmd
- end_cmd
- null_cmd_timer_expired
- null_cmd_end_timer
- null_complete_rq
- null_alloc_page
- null_free_page
- null_page_empty
- null_free_sector
- null_radix_tree_insert
- null_free_device_storage
- __null_lookup_page
- null_lookup_page
- null_insert_page
- null_flush_cache_page
- null_make_cache_space
- copy_to_nullb
- copy_from_nullb
- null_handle_discard
- null_handle_flush
- null_transfer
- null_handle_rq
- null_handle_bio
- null_stop_queue
- null_restart_queue_async
- null_handle_throttled
- null_handle_badblocks
- null_handle_memory_backed
- nullb_complete_cmd
- null_handle_cmd
- nullb_bwtimer_fn
- nullb_setup_bwtimer
- nullb_to_queue
- null_queue_bio
- should_timeout_request
- should_requeue_request
- null_timeout_rq
- null_queue_rq
- cleanup_queue
- cleanup_queues
- null_del_dev
- null_config_discard
- null_open
- null_release
- null_init_queue
- null_init_queues
- setup_commands
- setup_queues
- init_driver_queues
- null_gendisk_register
- null_init_tag_set
- null_validate_conf
- __null_setup_fault
- null_setup_fault
- null_add_dev
- null_init
- null_exit
1
2
3
4
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 #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
35
36
37
38
39
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
51
52
53
54
55
56
57
58
59
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 enum {
81 NULL_Q_BIO = 0,
82 NULL_Q_RQ = 1,
83 NULL_Q_MQ = 2,
84 };
85
86 static int g_no_sched;
87 module_param_named(no_sched, g_no_sched, int, 0444);
88 MODULE_PARM_DESC(no_sched, "No io scheduler");
89
90 static int g_submit_queues = 1;
91 module_param_named(submit_queues, g_submit_queues, int, 0444);
92 MODULE_PARM_DESC(submit_queues, "Number of submission queues");
93
94 static int g_home_node = NUMA_NO_NODE;
95 module_param_named(home_node, g_home_node, int, 0444);
96 MODULE_PARM_DESC(home_node, "Home node for the device");
97
98 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
99 static char g_timeout_str[80];
100 module_param_string(timeout, g_timeout_str, sizeof(g_timeout_str), 0444);
101
102 static char g_requeue_str[80];
103 module_param_string(requeue, g_requeue_str, sizeof(g_requeue_str), 0444);
104 #endif
105
106 static int g_queue_mode = NULL_Q_MQ;
107
108 static int null_param_store_val(const char *str, int *val, int min, int max)
109 {
110 int ret, new_val;
111
112 ret = kstrtoint(str, 10, &new_val);
113 if (ret)
114 return -EINVAL;
115
116 if (new_val < min || new_val > max)
117 return -EINVAL;
118
119 *val = new_val;
120 return 0;
121 }
122
123 static int null_set_queue_mode(const char *str, const struct kernel_param *kp)
124 {
125 return null_param_store_val(str, &g_queue_mode, NULL_Q_BIO, NULL_Q_MQ);
126 }
127
128 static const struct kernel_param_ops null_queue_mode_param_ops = {
129 .set = null_set_queue_mode,
130 .get = param_get_int,
131 };
132
133 device_param_cb(queue_mode, &null_queue_mode_param_ops, &g_queue_mode, 0444);
134 MODULE_PARM_DESC(queue_mode, "Block interface to use (0=bio,1=rq,2=multiqueue)");
135
136 static int g_gb = 250;
137 module_param_named(gb, g_gb, int, 0444);
138 MODULE_PARM_DESC(gb, "Size in GB");
139
140 static int g_bs = 512;
141 module_param_named(bs, g_bs, int, 0444);
142 MODULE_PARM_DESC(bs, "Block size (in bytes)");
143
144 static unsigned int nr_devices = 1;
145 module_param(nr_devices, uint, 0444);
146 MODULE_PARM_DESC(nr_devices, "Number of devices to register");
147
148 static bool g_blocking;
149 module_param_named(blocking, g_blocking, bool, 0444);
150 MODULE_PARM_DESC(blocking, "Register as a blocking blk-mq driver device");
151
152 static bool shared_tags;
153 module_param(shared_tags, bool, 0444);
154 MODULE_PARM_DESC(shared_tags, "Share tag set between devices for blk-mq");
155
156 static int g_irqmode = NULL_IRQ_SOFTIRQ;
157
158 static int null_set_irqmode(const char *str, const struct kernel_param *kp)
159 {
160 return null_param_store_val(str, &g_irqmode, NULL_IRQ_NONE,
161 NULL_IRQ_TIMER);
162 }
163
164 static const struct kernel_param_ops null_irqmode_param_ops = {
165 .set = null_set_irqmode,
166 .get = param_get_int,
167 };
168
169 device_param_cb(irqmode, &null_irqmode_param_ops, &g_irqmode, 0444);
170 MODULE_PARM_DESC(irqmode, "IRQ completion handler. 0-none, 1-softirq, 2-timer");
171
172 static unsigned long g_completion_nsec = 10000;
173 module_param_named(completion_nsec, g_completion_nsec, ulong, 0444);
174 MODULE_PARM_DESC(completion_nsec, "Time in ns to complete a request in hardware. Default: 10,000ns");
175
176 static int g_hw_queue_depth = 64;
177 module_param_named(hw_queue_depth, g_hw_queue_depth, int, 0444);
178 MODULE_PARM_DESC(hw_queue_depth, "Queue depth for each hardware queue. Default: 64");
179
180 static bool g_use_per_node_hctx;
181 module_param_named(use_per_node_hctx, g_use_per_node_hctx, bool, 0444);
182 MODULE_PARM_DESC(use_per_node_hctx, "Use per-node allocation for hardware context queues. Default: false");
183
184 static bool g_zoned;
185 module_param_named(zoned, g_zoned, bool, S_IRUGO);
186 MODULE_PARM_DESC(zoned, "Make device as a host-managed zoned block device. Default: false");
187
188 static unsigned long g_zone_size = 256;
189 module_param_named(zone_size, g_zone_size, ulong, S_IRUGO);
190 MODULE_PARM_DESC(zone_size, "Zone size in MB when block device is zoned. Must be power-of-two: Default: 256");
191
192 static unsigned int g_zone_nr_conv;
193 module_param_named(zone_nr_conv, g_zone_nr_conv, uint, 0444);
194 MODULE_PARM_DESC(zone_nr_conv, "Number of conventional zones when block device is zoned. Default: 0");
195
196 static struct nullb_device *null_alloc_dev(void);
197 static void null_free_dev(struct nullb_device *dev);
198 static void null_del_dev(struct nullb *nullb);
199 static int null_add_dev(struct nullb_device *dev);
200 static void null_free_device_storage(struct nullb_device *dev, bool is_cache);
201
202 static inline struct nullb_device *to_nullb_device(struct config_item *item)
203 {
204 return item ? container_of(item, struct nullb_device, item) : NULL;
205 }
206
207 static inline ssize_t nullb_device_uint_attr_show(unsigned int val, char *page)
208 {
209 return snprintf(page, PAGE_SIZE, "%u\n", val);
210 }
211
212 static inline ssize_t nullb_device_ulong_attr_show(unsigned long val,
213 char *page)
214 {
215 return snprintf(page, PAGE_SIZE, "%lu\n", val);
216 }
217
218 static inline ssize_t nullb_device_bool_attr_show(bool val, char *page)
219 {
220 return snprintf(page, PAGE_SIZE, "%u\n", val);
221 }
222
223 static ssize_t nullb_device_uint_attr_store(unsigned int *val,
224 const char *page, size_t count)
225 {
226 unsigned int tmp;
227 int result;
228
229 result = kstrtouint(page, 0, &tmp);
230 if (result)
231 return result;
232
233 *val = tmp;
234 return count;
235 }
236
237 static ssize_t nullb_device_ulong_attr_store(unsigned long *val,
238 const char *page, size_t count)
239 {
240 int result;
241 unsigned long tmp;
242
243 result = kstrtoul(page, 0, &tmp);
244 if (result)
245 return result;
246
247 *val = tmp;
248 return count;
249 }
250
251 static ssize_t nullb_device_bool_attr_store(bool *val, const char *page,
252 size_t count)
253 {
254 bool tmp;
255 int result;
256
257 result = kstrtobool(page, &tmp);
258 if (result)
259 return result;
260
261 *val = tmp;
262 return count;
263 }
264
265
266 #define NULLB_DEVICE_ATTR(NAME, TYPE) \
267 static ssize_t \
268 nullb_device_##NAME##_show(struct config_item *item, char *page) \
269 { \
270 return nullb_device_##TYPE##_attr_show( \
271 to_nullb_device(item)->NAME, page); \
272 } \
273 static ssize_t \
274 nullb_device_##NAME##_store(struct config_item *item, const char *page, \
275 size_t count) \
276 { \
277 if (test_bit(NULLB_DEV_FL_CONFIGURED, &to_nullb_device(item)->flags)) \
278 return -EBUSY; \
279 return nullb_device_##TYPE##_attr_store( \
280 &to_nullb_device(item)->NAME, page, count); \
281 } \
282 CONFIGFS_ATTR(nullb_device_, NAME);
283
284 NULLB_DEVICE_ATTR(size, ulong);
285 NULLB_DEVICE_ATTR(completion_nsec, ulong);
286 NULLB_DEVICE_ATTR(submit_queues, uint);
287 NULLB_DEVICE_ATTR(home_node, uint);
288 NULLB_DEVICE_ATTR(queue_mode, uint);
289 NULLB_DEVICE_ATTR(blocksize, uint);
290 NULLB_DEVICE_ATTR(irqmode, uint);
291 NULLB_DEVICE_ATTR(hw_queue_depth, uint);
292 NULLB_DEVICE_ATTR(index, uint);
293 NULLB_DEVICE_ATTR(blocking, bool);
294 NULLB_DEVICE_ATTR(use_per_node_hctx, bool);
295 NULLB_DEVICE_ATTR(memory_backed, bool);
296 NULLB_DEVICE_ATTR(discard, bool);
297 NULLB_DEVICE_ATTR(mbps, uint);
298 NULLB_DEVICE_ATTR(cache_size, ulong);
299 NULLB_DEVICE_ATTR(zoned, bool);
300 NULLB_DEVICE_ATTR(zone_size, ulong);
301 NULLB_DEVICE_ATTR(zone_nr_conv, uint);
302
303 static ssize_t nullb_device_power_show(struct config_item *item, char *page)
304 {
305 return nullb_device_bool_attr_show(to_nullb_device(item)->power, page);
306 }
307
308 static ssize_t nullb_device_power_store(struct config_item *item,
309 const char *page, size_t count)
310 {
311 struct nullb_device *dev = to_nullb_device(item);
312 bool newp = false;
313 ssize_t ret;
314
315 ret = nullb_device_bool_attr_store(&newp, page, count);
316 if (ret < 0)
317 return ret;
318
319 if (!dev->power && newp) {
320 if (test_and_set_bit(NULLB_DEV_FL_UP, &dev->flags))
321 return count;
322 if (null_add_dev(dev)) {
323 clear_bit(NULLB_DEV_FL_UP, &dev->flags);
324 return -ENOMEM;
325 }
326
327 set_bit(NULLB_DEV_FL_CONFIGURED, &dev->flags);
328 dev->power = newp;
329 } else if (dev->power && !newp) {
330 if (test_and_clear_bit(NULLB_DEV_FL_UP, &dev->flags)) {
331 mutex_lock(&lock);
332 dev->power = newp;
333 null_del_dev(dev->nullb);
334 mutex_unlock(&lock);
335 }
336 clear_bit(NULLB_DEV_FL_CONFIGURED, &dev->flags);
337 }
338
339 return count;
340 }
341
342 CONFIGFS_ATTR(nullb_device_, power);
343
344 static ssize_t nullb_device_badblocks_show(struct config_item *item, char *page)
345 {
346 struct nullb_device *t_dev = to_nullb_device(item);
347
348 return badblocks_show(&t_dev->badblocks, page, 0);
349 }
350
351 static ssize_t nullb_device_badblocks_store(struct config_item *item,
352 const char *page, size_t count)
353 {
354 struct nullb_device *t_dev = to_nullb_device(item);
355 char *orig, *buf, *tmp;
356 u64 start, end;
357 int ret;
358
359 orig = kstrndup(page, count, GFP_KERNEL);
360 if (!orig)
361 return -ENOMEM;
362
363 buf = strstrip(orig);
364
365 ret = -EINVAL;
366 if (buf[0] != '+' && buf[0] != '-')
367 goto out;
368 tmp = strchr(&buf[1], '-');
369 if (!tmp)
370 goto out;
371 *tmp = '\0';
372 ret = kstrtoull(buf + 1, 0, &start);
373 if (ret)
374 goto out;
375 ret = kstrtoull(tmp + 1, 0, &end);
376 if (ret)
377 goto out;
378 ret = -EINVAL;
379 if (start > end)
380 goto out;
381
382 cmpxchg(&t_dev->badblocks.shift, -1, 0);
383 if (buf[0] == '+')
384 ret = badblocks_set(&t_dev->badblocks, start,
385 end - start + 1, 1);
386 else
387 ret = badblocks_clear(&t_dev->badblocks, start,
388 end - start + 1);
389 if (ret == 0)
390 ret = count;
391 out:
392 kfree(orig);
393 return ret;
394 }
395 CONFIGFS_ATTR(nullb_device_, badblocks);
396
397 static struct configfs_attribute *nullb_device_attrs[] = {
398 &nullb_device_attr_size,
399 &nullb_device_attr_completion_nsec,
400 &nullb_device_attr_submit_queues,
401 &nullb_device_attr_home_node,
402 &nullb_device_attr_queue_mode,
403 &nullb_device_attr_blocksize,
404 &nullb_device_attr_irqmode,
405 &nullb_device_attr_hw_queue_depth,
406 &nullb_device_attr_index,
407 &nullb_device_attr_blocking,
408 &nullb_device_attr_use_per_node_hctx,
409 &nullb_device_attr_power,
410 &nullb_device_attr_memory_backed,
411 &nullb_device_attr_discard,
412 &nullb_device_attr_mbps,
413 &nullb_device_attr_cache_size,
414 &nullb_device_attr_badblocks,
415 &nullb_device_attr_zoned,
416 &nullb_device_attr_zone_size,
417 &nullb_device_attr_zone_nr_conv,
418 NULL,
419 };
420
421 static void nullb_device_release(struct config_item *item)
422 {
423 struct nullb_device *dev = to_nullb_device(item);
424
425 null_free_device_storage(dev, false);
426 null_free_dev(dev);
427 }
428
429 static struct configfs_item_operations nullb_device_ops = {
430 .release = nullb_device_release,
431 };
432
433 static const struct config_item_type nullb_device_type = {
434 .ct_item_ops = &nullb_device_ops,
435 .ct_attrs = nullb_device_attrs,
436 .ct_owner = THIS_MODULE,
437 };
438
439 static struct
440 config_item *nullb_group_make_item(struct config_group *group, const char *name)
441 {
442 struct nullb_device *dev;
443
444 dev = null_alloc_dev();
445 if (!dev)
446 return ERR_PTR(-ENOMEM);
447
448 config_item_init_type_name(&dev->item, name, &nullb_device_type);
449
450 return &dev->item;
451 }
452
453 static void
454 nullb_group_drop_item(struct config_group *group, struct config_item *item)
455 {
456 struct nullb_device *dev = to_nullb_device(item);
457
458 if (test_and_clear_bit(NULLB_DEV_FL_UP, &dev->flags)) {
459 mutex_lock(&lock);
460 dev->power = false;
461 null_del_dev(dev->nullb);
462 mutex_unlock(&lock);
463 }
464
465 config_item_put(item);
466 }
467
468 static ssize_t memb_group_features_show(struct config_item *item, char *page)
469 {
470 return snprintf(page, PAGE_SIZE, "memory_backed,discard,bandwidth,cache,badblocks,zoned,zone_size\n");
471 }
472
473 CONFIGFS_ATTR_RO(memb_group_, features);
474
475 static struct configfs_attribute *nullb_group_attrs[] = {
476 &memb_group_attr_features,
477 NULL,
478 };
479
480 static struct configfs_group_operations nullb_group_ops = {
481 .make_item = nullb_group_make_item,
482 .drop_item = nullb_group_drop_item,
483 };
484
485 static const struct config_item_type nullb_group_type = {
486 .ct_group_ops = &nullb_group_ops,
487 .ct_attrs = nullb_group_attrs,
488 .ct_owner = THIS_MODULE,
489 };
490
491 static struct configfs_subsystem nullb_subsys = {
492 .su_group = {
493 .cg_item = {
494 .ci_namebuf = "nullb",
495 .ci_type = &nullb_group_type,
496 },
497 },
498 };
499
500 static inline int null_cache_active(struct nullb *nullb)
501 {
502 return test_bit(NULLB_DEV_FL_CACHE, &nullb->dev->flags);
503 }
504
505 static struct nullb_device *null_alloc_dev(void)
506 {
507 struct nullb_device *dev;
508
509 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
510 if (!dev)
511 return NULL;
512 INIT_RADIX_TREE(&dev->data, GFP_ATOMIC);
513 INIT_RADIX_TREE(&dev->cache, GFP_ATOMIC);
514 if (badblocks_init(&dev->badblocks, 0)) {
515 kfree(dev);
516 return NULL;
517 }
518
519 dev->size = g_gb * 1024;
520 dev->completion_nsec = g_completion_nsec;
521 dev->submit_queues = g_submit_queues;
522 dev->home_node = g_home_node;
523 dev->queue_mode = g_queue_mode;
524 dev->blocksize = g_bs;
525 dev->irqmode = g_irqmode;
526 dev->hw_queue_depth = g_hw_queue_depth;
527 dev->blocking = g_blocking;
528 dev->use_per_node_hctx = g_use_per_node_hctx;
529 dev->zoned = g_zoned;
530 dev->zone_size = g_zone_size;
531 dev->zone_nr_conv = g_zone_nr_conv;
532 return dev;
533 }
534
535 static void null_free_dev(struct nullb_device *dev)
536 {
537 if (!dev)
538 return;
539
540 null_zone_exit(dev);
541 badblocks_exit(&dev->badblocks);
542 kfree(dev);
543 }
544
545 static void put_tag(struct nullb_queue *nq, unsigned int tag)
546 {
547 clear_bit_unlock(tag, nq->tag_map);
548
549 if (waitqueue_active(&nq->wait))
550 wake_up(&nq->wait);
551 }
552
553 static unsigned int get_tag(struct nullb_queue *nq)
554 {
555 unsigned int tag;
556
557 do {
558 tag = find_first_zero_bit(nq->tag_map, nq->queue_depth);
559 if (tag >= nq->queue_depth)
560 return -1U;
561 } while (test_and_set_bit_lock(tag, nq->tag_map));
562
563 return tag;
564 }
565
566 static void free_cmd(struct nullb_cmd *cmd)
567 {
568 put_tag(cmd->nq, cmd->tag);
569 }
570
571 static enum hrtimer_restart null_cmd_timer_expired(struct hrtimer *timer);
572
573 static struct nullb_cmd *__alloc_cmd(struct nullb_queue *nq)
574 {
575 struct nullb_cmd *cmd;
576 unsigned int tag;
577
578 tag = get_tag(nq);
579 if (tag != -1U) {
580 cmd = &nq->cmds[tag];
581 cmd->tag = tag;
582 cmd->error = BLK_STS_OK;
583 cmd->nq = nq;
584 if (nq->dev->irqmode == NULL_IRQ_TIMER) {
585 hrtimer_init(&cmd->timer, CLOCK_MONOTONIC,
586 HRTIMER_MODE_REL);
587 cmd->timer.function = null_cmd_timer_expired;
588 }
589 return cmd;
590 }
591
592 return NULL;
593 }
594
595 static struct nullb_cmd *alloc_cmd(struct nullb_queue *nq, int can_wait)
596 {
597 struct nullb_cmd *cmd;
598 DEFINE_WAIT(wait);
599
600 cmd = __alloc_cmd(nq);
601 if (cmd || !can_wait)
602 return cmd;
603
604 do {
605 prepare_to_wait(&nq->wait, &wait, TASK_UNINTERRUPTIBLE);
606 cmd = __alloc_cmd(nq);
607 if (cmd)
608 break;
609
610 io_schedule();
611 } while (1);
612
613 finish_wait(&nq->wait, &wait);
614 return cmd;
615 }
616
617 static void end_cmd(struct nullb_cmd *cmd)
618 {
619 int queue_mode = cmd->nq->dev->queue_mode;
620
621 switch (queue_mode) {
622 case NULL_Q_MQ:
623 blk_mq_end_request(cmd->rq, cmd->error);
624 return;
625 case NULL_Q_BIO:
626 cmd->bio->bi_status = cmd->error;
627 bio_endio(cmd->bio);
628 break;
629 }
630
631 free_cmd(cmd);
632 }
633
634 static enum hrtimer_restart null_cmd_timer_expired(struct hrtimer *timer)
635 {
636 end_cmd(container_of(timer, struct nullb_cmd, timer));
637
638 return HRTIMER_NORESTART;
639 }
640
641 static void null_cmd_end_timer(struct nullb_cmd *cmd)
642 {
643 ktime_t kt = cmd->nq->dev->completion_nsec;
644
645 hrtimer_start(&cmd->timer, kt, HRTIMER_MODE_REL);
646 }
647
648 static void null_complete_rq(struct request *rq)
649 {
650 end_cmd(blk_mq_rq_to_pdu(rq));
651 }
652
653 static struct nullb_page *null_alloc_page(gfp_t gfp_flags)
654 {
655 struct nullb_page *t_page;
656
657 t_page = kmalloc(sizeof(struct nullb_page), gfp_flags);
658 if (!t_page)
659 goto out;
660
661 t_page->page = alloc_pages(gfp_flags, 0);
662 if (!t_page->page)
663 goto out_freepage;
664
665 memset(t_page->bitmap, 0, sizeof(t_page->bitmap));
666 return t_page;
667 out_freepage:
668 kfree(t_page);
669 out:
670 return NULL;
671 }
672
673 static void null_free_page(struct nullb_page *t_page)
674 {
675 __set_bit(NULLB_PAGE_FREE, t_page->bitmap);
676 if (test_bit(NULLB_PAGE_LOCK, t_page->bitmap))
677 return;
678 __free_page(t_page->page);
679 kfree(t_page);
680 }
681
682 static bool null_page_empty(struct nullb_page *page)
683 {
684 int size = MAP_SZ - 2;
685
686 return find_first_bit(page->bitmap, size) == size;
687 }
688
689 static void null_free_sector(struct nullb *nullb, sector_t sector,
690 bool is_cache)
691 {
692 unsigned int sector_bit;
693 u64 idx;
694 struct nullb_page *t_page, *ret;
695 struct radix_tree_root *root;
696
697 root = is_cache ? &nullb->dev->cache : &nullb->dev->data;
698 idx = sector >> PAGE_SECTORS_SHIFT;
699 sector_bit = (sector & SECTOR_MASK);
700
701 t_page = radix_tree_lookup(root, idx);
702 if (t_page) {
703 __clear_bit(sector_bit, t_page->bitmap);
704
705 if (null_page_empty(t_page)) {
706 ret = radix_tree_delete_item(root, idx, t_page);
707 WARN_ON(ret != t_page);
708 null_free_page(ret);
709 if (is_cache)
710 nullb->dev->curr_cache -= PAGE_SIZE;
711 }
712 }
713 }
714
715 static struct nullb_page *null_radix_tree_insert(struct nullb *nullb, u64 idx,
716 struct nullb_page *t_page, bool is_cache)
717 {
718 struct radix_tree_root *root;
719
720 root = is_cache ? &nullb->dev->cache : &nullb->dev->data;
721
722 if (radix_tree_insert(root, idx, t_page)) {
723 null_free_page(t_page);
724 t_page = radix_tree_lookup(root, idx);
725 WARN_ON(!t_page || t_page->page->index != idx);
726 } else if (is_cache)
727 nullb->dev->curr_cache += PAGE_SIZE;
728
729 return t_page;
730 }
731
732 static void null_free_device_storage(struct nullb_device *dev, bool is_cache)
733 {
734 unsigned long pos = 0;
735 int nr_pages;
736 struct nullb_page *ret, *t_pages[FREE_BATCH];
737 struct radix_tree_root *root;
738
739 root = is_cache ? &dev->cache : &dev->data;
740
741 do {
742 int i;
743
744 nr_pages = radix_tree_gang_lookup(root,
745 (void **)t_pages, pos, FREE_BATCH);
746
747 for (i = 0; i < nr_pages; i++) {
748 pos = t_pages[i]->page->index;
749 ret = radix_tree_delete_item(root, pos, t_pages[i]);
750 WARN_ON(ret != t_pages[i]);
751 null_free_page(ret);
752 }
753
754 pos++;
755 } while (nr_pages == FREE_BATCH);
756
757 if (is_cache)
758 dev->curr_cache = 0;
759 }
760
761 static struct nullb_page *__null_lookup_page(struct nullb *nullb,
762 sector_t sector, bool for_write, bool is_cache)
763 {
764 unsigned int sector_bit;
765 u64 idx;
766 struct nullb_page *t_page;
767 struct radix_tree_root *root;
768
769 idx = sector >> PAGE_SECTORS_SHIFT;
770 sector_bit = (sector & SECTOR_MASK);
771
772 root = is_cache ? &nullb->dev->cache : &nullb->dev->data;
773 t_page = radix_tree_lookup(root, idx);
774 WARN_ON(t_page && t_page->page->index != idx);
775
776 if (t_page && (for_write || test_bit(sector_bit, t_page->bitmap)))
777 return t_page;
778
779 return NULL;
780 }
781
782 static struct nullb_page *null_lookup_page(struct nullb *nullb,
783 sector_t sector, bool for_write, bool ignore_cache)
784 {
785 struct nullb_page *page = NULL;
786
787 if (!ignore_cache)
788 page = __null_lookup_page(nullb, sector, for_write, true);
789 if (page)
790 return page;
791 return __null_lookup_page(nullb, sector, for_write, false);
792 }
793
794 static struct nullb_page *null_insert_page(struct nullb *nullb,
795 sector_t sector, bool ignore_cache)
796 __releases(&nullb->lock)
797 __acquires(&nullb->lock)
798 {
799 u64 idx;
800 struct nullb_page *t_page;
801
802 t_page = null_lookup_page(nullb, sector, true, ignore_cache);
803 if (t_page)
804 return t_page;
805
806 spin_unlock_irq(&nullb->lock);
807
808 t_page = null_alloc_page(GFP_NOIO);
809 if (!t_page)
810 goto out_lock;
811
812 if (radix_tree_preload(GFP_NOIO))
813 goto out_freepage;
814
815 spin_lock_irq(&nullb->lock);
816 idx = sector >> PAGE_SECTORS_SHIFT;
817 t_page->page->index = idx;
818 t_page = null_radix_tree_insert(nullb, idx, t_page, !ignore_cache);
819 radix_tree_preload_end();
820
821 return t_page;
822 out_freepage:
823 null_free_page(t_page);
824 out_lock:
825 spin_lock_irq(&nullb->lock);
826 return null_lookup_page(nullb, sector, true, ignore_cache);
827 }
828
829 static int null_flush_cache_page(struct nullb *nullb, struct nullb_page *c_page)
830 {
831 int i;
832 unsigned int offset;
833 u64 idx;
834 struct nullb_page *t_page, *ret;
835 void *dst, *src;
836
837 idx = c_page->page->index;
838
839 t_page = null_insert_page(nullb, idx << PAGE_SECTORS_SHIFT, true);
840
841 __clear_bit(NULLB_PAGE_LOCK, c_page->bitmap);
842 if (test_bit(NULLB_PAGE_FREE, c_page->bitmap)) {
843 null_free_page(c_page);
844 if (t_page && null_page_empty(t_page)) {
845 ret = radix_tree_delete_item(&nullb->dev->data,
846 idx, t_page);
847 null_free_page(t_page);
848 }
849 return 0;
850 }
851
852 if (!t_page)
853 return -ENOMEM;
854
855 src = kmap_atomic(c_page->page);
856 dst = kmap_atomic(t_page->page);
857
858 for (i = 0; i < PAGE_SECTORS;
859 i += (nullb->dev->blocksize >> SECTOR_SHIFT)) {
860 if (test_bit(i, c_page->bitmap)) {
861 offset = (i << SECTOR_SHIFT);
862 memcpy(dst + offset, src + offset,
863 nullb->dev->blocksize);
864 __set_bit(i, t_page->bitmap);
865 }
866 }
867
868 kunmap_atomic(dst);
869 kunmap_atomic(src);
870
871 ret = radix_tree_delete_item(&nullb->dev->cache, idx, c_page);
872 null_free_page(ret);
873 nullb->dev->curr_cache -= PAGE_SIZE;
874
875 return 0;
876 }
877
878 static int null_make_cache_space(struct nullb *nullb, unsigned long n)
879 {
880 int i, err, nr_pages;
881 struct nullb_page *c_pages[FREE_BATCH];
882 unsigned long flushed = 0, one_round;
883
884 again:
885 if ((nullb->dev->cache_size * 1024 * 1024) >
886 nullb->dev->curr_cache + n || nullb->dev->curr_cache == 0)
887 return 0;
888
889 nr_pages = radix_tree_gang_lookup(&nullb->dev->cache,
890 (void **)c_pages, nullb->cache_flush_pos, FREE_BATCH);
891
892
893
894
895 for (i = 0; i < nr_pages; i++) {
896 nullb->cache_flush_pos = c_pages[i]->page->index;
897
898
899
900
901 if (test_bit(NULLB_PAGE_LOCK, c_pages[i]->bitmap))
902 c_pages[i] = NULL;
903 else
904 __set_bit(NULLB_PAGE_LOCK, c_pages[i]->bitmap);
905 }
906
907 one_round = 0;
908 for (i = 0; i < nr_pages; i++) {
909 if (c_pages[i] == NULL)
910 continue;
911 err = null_flush_cache_page(nullb, c_pages[i]);
912 if (err)
913 return err;
914 one_round++;
915 }
916 flushed += one_round << PAGE_SHIFT;
917
918 if (n > flushed) {
919 if (nr_pages == 0)
920 nullb->cache_flush_pos = 0;
921 if (one_round == 0) {
922
923 spin_unlock_irq(&nullb->lock);
924 spin_lock_irq(&nullb->lock);
925 }
926 goto again;
927 }
928 return 0;
929 }
930
931 static int copy_to_nullb(struct nullb *nullb, struct page *source,
932 unsigned int off, sector_t sector, size_t n, bool is_fua)
933 {
934 size_t temp, count = 0;
935 unsigned int offset;
936 struct nullb_page *t_page;
937 void *dst, *src;
938
939 while (count < n) {
940 temp = min_t(size_t, nullb->dev->blocksize, n - count);
941
942 if (null_cache_active(nullb) && !is_fua)
943 null_make_cache_space(nullb, PAGE_SIZE);
944
945 offset = (sector & SECTOR_MASK) << SECTOR_SHIFT;
946 t_page = null_insert_page(nullb, sector,
947 !null_cache_active(nullb) || is_fua);
948 if (!t_page)
949 return -ENOSPC;
950
951 src = kmap_atomic(source);
952 dst = kmap_atomic(t_page->page);
953 memcpy(dst + offset, src + off + count, temp);
954 kunmap_atomic(dst);
955 kunmap_atomic(src);
956
957 __set_bit(sector & SECTOR_MASK, t_page->bitmap);
958
959 if (is_fua)
960 null_free_sector(nullb, sector, true);
961
962 count += temp;
963 sector += temp >> SECTOR_SHIFT;
964 }
965 return 0;
966 }
967
968 static int copy_from_nullb(struct nullb *nullb, struct page *dest,
969 unsigned int off, sector_t sector, size_t n)
970 {
971 size_t temp, count = 0;
972 unsigned int offset;
973 struct nullb_page *t_page;
974 void *dst, *src;
975
976 while (count < n) {
977 temp = min_t(size_t, nullb->dev->blocksize, n - count);
978
979 offset = (sector & SECTOR_MASK) << SECTOR_SHIFT;
980 t_page = null_lookup_page(nullb, sector, false,
981 !null_cache_active(nullb));
982
983 dst = kmap_atomic(dest);
984 if (!t_page) {
985 memset(dst + off + count, 0, temp);
986 goto next;
987 }
988 src = kmap_atomic(t_page->page);
989 memcpy(dst + off + count, src + offset, temp);
990 kunmap_atomic(src);
991 next:
992 kunmap_atomic(dst);
993
994 count += temp;
995 sector += temp >> SECTOR_SHIFT;
996 }
997 return 0;
998 }
999
1000 static void null_handle_discard(struct nullb *nullb, sector_t sector, size_t n)
1001 {
1002 size_t temp;
1003
1004 spin_lock_irq(&nullb->lock);
1005 while (n > 0) {
1006 temp = min_t(size_t, n, nullb->dev->blocksize);
1007 null_free_sector(nullb, sector, false);
1008 if (null_cache_active(nullb))
1009 null_free_sector(nullb, sector, true);
1010 sector += temp >> SECTOR_SHIFT;
1011 n -= temp;
1012 }
1013 spin_unlock_irq(&nullb->lock);
1014 }
1015
1016 static int null_handle_flush(struct nullb *nullb)
1017 {
1018 int err;
1019
1020 if (!null_cache_active(nullb))
1021 return 0;
1022
1023 spin_lock_irq(&nullb->lock);
1024 while (true) {
1025 err = null_make_cache_space(nullb,
1026 nullb->dev->cache_size * 1024 * 1024);
1027 if (err || nullb->dev->curr_cache == 0)
1028 break;
1029 }
1030
1031 WARN_ON(!radix_tree_empty(&nullb->dev->cache));
1032 spin_unlock_irq(&nullb->lock);
1033 return err;
1034 }
1035
1036 static int null_transfer(struct nullb *nullb, struct page *page,
1037 unsigned int len, unsigned int off, bool is_write, sector_t sector,
1038 bool is_fua)
1039 {
1040 int err = 0;
1041
1042 if (!is_write) {
1043 err = copy_from_nullb(nullb, page, off, sector, len);
1044 flush_dcache_page(page);
1045 } else {
1046 flush_dcache_page(page);
1047 err = copy_to_nullb(nullb, page, off, sector, len, is_fua);
1048 }
1049
1050 return err;
1051 }
1052
1053 static int null_handle_rq(struct nullb_cmd *cmd)
1054 {
1055 struct request *rq = cmd->rq;
1056 struct nullb *nullb = cmd->nq->dev->nullb;
1057 int err;
1058 unsigned int len;
1059 sector_t sector;
1060 struct req_iterator iter;
1061 struct bio_vec bvec;
1062
1063 sector = blk_rq_pos(rq);
1064
1065 if (req_op(rq) == REQ_OP_DISCARD) {
1066 null_handle_discard(nullb, sector, blk_rq_bytes(rq));
1067 return 0;
1068 }
1069
1070 spin_lock_irq(&nullb->lock);
1071 rq_for_each_segment(bvec, rq, iter) {
1072 len = bvec.bv_len;
1073 err = null_transfer(nullb, bvec.bv_page, len, bvec.bv_offset,
1074 op_is_write(req_op(rq)), sector,
1075 req_op(rq) & REQ_FUA);
1076 if (err) {
1077 spin_unlock_irq(&nullb->lock);
1078 return err;
1079 }
1080 sector += len >> SECTOR_SHIFT;
1081 }
1082 spin_unlock_irq(&nullb->lock);
1083
1084 return 0;
1085 }
1086
1087 static int null_handle_bio(struct nullb_cmd *cmd)
1088 {
1089 struct bio *bio = cmd->bio;
1090 struct nullb *nullb = cmd->nq->dev->nullb;
1091 int err;
1092 unsigned int len;
1093 sector_t sector;
1094 struct bio_vec bvec;
1095 struct bvec_iter iter;
1096
1097 sector = bio->bi_iter.bi_sector;
1098
1099 if (bio_op(bio) == REQ_OP_DISCARD) {
1100 null_handle_discard(nullb, sector,
1101 bio_sectors(bio) << SECTOR_SHIFT);
1102 return 0;
1103 }
1104
1105 spin_lock_irq(&nullb->lock);
1106 bio_for_each_segment(bvec, bio, iter) {
1107 len = bvec.bv_len;
1108 err = null_transfer(nullb, bvec.bv_page, len, bvec.bv_offset,
1109 op_is_write(bio_op(bio)), sector,
1110 bio->bi_opf & REQ_FUA);
1111 if (err) {
1112 spin_unlock_irq(&nullb->lock);
1113 return err;
1114 }
1115 sector += len >> SECTOR_SHIFT;
1116 }
1117 spin_unlock_irq(&nullb->lock);
1118 return 0;
1119 }
1120
1121 static void null_stop_queue(struct nullb *nullb)
1122 {
1123 struct request_queue *q = nullb->q;
1124
1125 if (nullb->dev->queue_mode == NULL_Q_MQ)
1126 blk_mq_stop_hw_queues(q);
1127 }
1128
1129 static void null_restart_queue_async(struct nullb *nullb)
1130 {
1131 struct request_queue *q = nullb->q;
1132
1133 if (nullb->dev->queue_mode == NULL_Q_MQ)
1134 blk_mq_start_stopped_hw_queues(q, true);
1135 }
1136
1137 static inline blk_status_t null_handle_throttled(struct nullb_cmd *cmd)
1138 {
1139 struct nullb_device *dev = cmd->nq->dev;
1140 struct nullb *nullb = dev->nullb;
1141 blk_status_t sts = BLK_STS_OK;
1142 struct request *rq = cmd->rq;
1143
1144 if (!hrtimer_active(&nullb->bw_timer))
1145 hrtimer_restart(&nullb->bw_timer);
1146
1147 if (atomic_long_sub_return(blk_rq_bytes(rq), &nullb->cur_bytes) < 0) {
1148 null_stop_queue(nullb);
1149
1150 if (atomic_long_read(&nullb->cur_bytes) > 0)
1151 null_restart_queue_async(nullb);
1152
1153 sts = BLK_STS_DEV_RESOURCE;
1154 }
1155 return sts;
1156 }
1157
1158 static inline blk_status_t null_handle_badblocks(struct nullb_cmd *cmd,
1159 sector_t sector,
1160 sector_t nr_sectors)
1161 {
1162 struct badblocks *bb = &cmd->nq->dev->badblocks;
1163 sector_t first_bad;
1164 int bad_sectors;
1165
1166 if (badblocks_check(bb, sector, nr_sectors, &first_bad, &bad_sectors))
1167 return BLK_STS_IOERR;
1168
1169 return BLK_STS_OK;
1170 }
1171
1172 static inline blk_status_t null_handle_memory_backed(struct nullb_cmd *cmd,
1173 enum req_opf op)
1174 {
1175 struct nullb_device *dev = cmd->nq->dev;
1176 int err;
1177
1178 if (dev->queue_mode == NULL_Q_BIO)
1179 err = null_handle_bio(cmd);
1180 else
1181 err = null_handle_rq(cmd);
1182
1183 return errno_to_blk_status(err);
1184 }
1185
1186 static inline void nullb_complete_cmd(struct nullb_cmd *cmd)
1187 {
1188
1189 switch (cmd->nq->dev->irqmode) {
1190 case NULL_IRQ_SOFTIRQ:
1191 switch (cmd->nq->dev->queue_mode) {
1192 case NULL_Q_MQ:
1193 blk_mq_complete_request(cmd->rq);
1194 break;
1195 case NULL_Q_BIO:
1196
1197
1198
1199 end_cmd(cmd);
1200 break;
1201 }
1202 break;
1203 case NULL_IRQ_NONE:
1204 end_cmd(cmd);
1205 break;
1206 case NULL_IRQ_TIMER:
1207 null_cmd_end_timer(cmd);
1208 break;
1209 }
1210 }
1211
1212 static blk_status_t null_handle_cmd(struct nullb_cmd *cmd, sector_t sector,
1213 sector_t nr_sectors, enum req_opf op)
1214 {
1215 struct nullb_device *dev = cmd->nq->dev;
1216 struct nullb *nullb = dev->nullb;
1217 blk_status_t sts;
1218
1219 if (test_bit(NULLB_DEV_FL_THROTTLED, &dev->flags)) {
1220 sts = null_handle_throttled(cmd);
1221 if (sts != BLK_STS_OK)
1222 return sts;
1223 }
1224
1225 if (op == REQ_OP_FLUSH) {
1226 cmd->error = errno_to_blk_status(null_handle_flush(nullb));
1227 goto out;
1228 }
1229
1230 if (nullb->dev->badblocks.shift != -1) {
1231 cmd->error = null_handle_badblocks(cmd, sector, nr_sectors);
1232 if (cmd->error != BLK_STS_OK)
1233 goto out;
1234 }
1235
1236 if (dev->memory_backed)
1237 cmd->error = null_handle_memory_backed(cmd, op);
1238
1239 if (!cmd->error && dev->zoned)
1240 cmd->error = null_handle_zoned(cmd, op, sector, nr_sectors);
1241
1242 out:
1243 nullb_complete_cmd(cmd);
1244 return BLK_STS_OK;
1245 }
1246
1247 static enum hrtimer_restart nullb_bwtimer_fn(struct hrtimer *timer)
1248 {
1249 struct nullb *nullb = container_of(timer, struct nullb, bw_timer);
1250 ktime_t timer_interval = ktime_set(0, TIMER_INTERVAL);
1251 unsigned int mbps = nullb->dev->mbps;
1252
1253 if (atomic_long_read(&nullb->cur_bytes) == mb_per_tick(mbps))
1254 return HRTIMER_NORESTART;
1255
1256 atomic_long_set(&nullb->cur_bytes, mb_per_tick(mbps));
1257 null_restart_queue_async(nullb);
1258
1259 hrtimer_forward_now(&nullb->bw_timer, timer_interval);
1260
1261 return HRTIMER_RESTART;
1262 }
1263
1264 static void nullb_setup_bwtimer(struct nullb *nullb)
1265 {
1266 ktime_t timer_interval = ktime_set(0, TIMER_INTERVAL);
1267
1268 hrtimer_init(&nullb->bw_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
1269 nullb->bw_timer.function = nullb_bwtimer_fn;
1270 atomic_long_set(&nullb->cur_bytes, mb_per_tick(nullb->dev->mbps));
1271 hrtimer_start(&nullb->bw_timer, timer_interval, HRTIMER_MODE_REL);
1272 }
1273
1274 static struct nullb_queue *nullb_to_queue(struct nullb *nullb)
1275 {
1276 int index = 0;
1277
1278 if (nullb->nr_queues != 1)
1279 index = raw_smp_processor_id() / ((nr_cpu_ids + nullb->nr_queues - 1) / nullb->nr_queues);
1280
1281 return &nullb->queues[index];
1282 }
1283
1284 static blk_qc_t null_queue_bio(struct request_queue *q, struct bio *bio)
1285 {
1286 sector_t sector = bio->bi_iter.bi_sector;
1287 sector_t nr_sectors = bio_sectors(bio);
1288 struct nullb *nullb = q->queuedata;
1289 struct nullb_queue *nq = nullb_to_queue(nullb);
1290 struct nullb_cmd *cmd;
1291
1292 cmd = alloc_cmd(nq, 1);
1293 cmd->bio = bio;
1294
1295 null_handle_cmd(cmd, sector, nr_sectors, bio_op(bio));
1296 return BLK_QC_T_NONE;
1297 }
1298
1299 static bool should_timeout_request(struct request *rq)
1300 {
1301 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
1302 if (g_timeout_str[0])
1303 return should_fail(&null_timeout_attr, 1);
1304 #endif
1305 return false;
1306 }
1307
1308 static bool should_requeue_request(struct request *rq)
1309 {
1310 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
1311 if (g_requeue_str[0])
1312 return should_fail(&null_requeue_attr, 1);
1313 #endif
1314 return false;
1315 }
1316
1317 static enum blk_eh_timer_return null_timeout_rq(struct request *rq, bool res)
1318 {
1319 pr_info("rq %p timed out\n", rq);
1320 blk_mq_complete_request(rq);
1321 return BLK_EH_DONE;
1322 }
1323
1324 static blk_status_t null_queue_rq(struct blk_mq_hw_ctx *hctx,
1325 const struct blk_mq_queue_data *bd)
1326 {
1327 struct nullb_cmd *cmd = blk_mq_rq_to_pdu(bd->rq);
1328 struct nullb_queue *nq = hctx->driver_data;
1329 sector_t nr_sectors = blk_rq_sectors(bd->rq);
1330 sector_t sector = blk_rq_pos(bd->rq);
1331
1332 might_sleep_if(hctx->flags & BLK_MQ_F_BLOCKING);
1333
1334 if (nq->dev->irqmode == NULL_IRQ_TIMER) {
1335 hrtimer_init(&cmd->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
1336 cmd->timer.function = null_cmd_timer_expired;
1337 }
1338 cmd->rq = bd->rq;
1339 cmd->error = BLK_STS_OK;
1340 cmd->nq = nq;
1341
1342 blk_mq_start_request(bd->rq);
1343
1344 if (should_requeue_request(bd->rq)) {
1345
1346
1347
1348
1349 nq->requeue_selection++;
1350 if (nq->requeue_selection & 1)
1351 return BLK_STS_RESOURCE;
1352 else {
1353 blk_mq_requeue_request(bd->rq, true);
1354 return BLK_STS_OK;
1355 }
1356 }
1357 if (should_timeout_request(bd->rq))
1358 return BLK_STS_OK;
1359
1360 return null_handle_cmd(cmd, sector, nr_sectors, req_op(bd->rq));
1361 }
1362
1363 static const struct blk_mq_ops null_mq_ops = {
1364 .queue_rq = null_queue_rq,
1365 .complete = null_complete_rq,
1366 .timeout = null_timeout_rq,
1367 };
1368
1369 static void cleanup_queue(struct nullb_queue *nq)
1370 {
1371 kfree(nq->tag_map);
1372 kfree(nq->cmds);
1373 }
1374
1375 static void cleanup_queues(struct nullb *nullb)
1376 {
1377 int i;
1378
1379 for (i = 0; i < nullb->nr_queues; i++)
1380 cleanup_queue(&nullb->queues[i]);
1381
1382 kfree(nullb->queues);
1383 }
1384
1385 static void null_del_dev(struct nullb *nullb)
1386 {
1387 struct nullb_device *dev;
1388
1389 if (!nullb)
1390 return;
1391
1392 dev = nullb->dev;
1393
1394 ida_simple_remove(&nullb_indexes, nullb->index);
1395
1396 list_del_init(&nullb->list);
1397
1398 del_gendisk(nullb->disk);
1399
1400 if (test_bit(NULLB_DEV_FL_THROTTLED, &nullb->dev->flags)) {
1401 hrtimer_cancel(&nullb->bw_timer);
1402 atomic_long_set(&nullb->cur_bytes, LONG_MAX);
1403 null_restart_queue_async(nullb);
1404 }
1405
1406 blk_cleanup_queue(nullb->q);
1407 if (dev->queue_mode == NULL_Q_MQ &&
1408 nullb->tag_set == &nullb->__tag_set)
1409 blk_mq_free_tag_set(nullb->tag_set);
1410 put_disk(nullb->disk);
1411 cleanup_queues(nullb);
1412 if (null_cache_active(nullb))
1413 null_free_device_storage(nullb->dev, true);
1414 kfree(nullb);
1415 dev->nullb = NULL;
1416 }
1417
1418 static void null_config_discard(struct nullb *nullb)
1419 {
1420 if (nullb->dev->discard == false)
1421 return;
1422 nullb->q->limits.discard_granularity = nullb->dev->blocksize;
1423 nullb->q->limits.discard_alignment = nullb->dev->blocksize;
1424 blk_queue_max_discard_sectors(nullb->q, UINT_MAX >> 9);
1425 blk_queue_flag_set(QUEUE_FLAG_DISCARD, nullb->q);
1426 }
1427
1428 static int null_open(struct block_device *bdev, fmode_t mode)
1429 {
1430 return 0;
1431 }
1432
1433 static void null_release(struct gendisk *disk, fmode_t mode)
1434 {
1435 }
1436
1437 static const struct block_device_operations null_fops = {
1438 .owner = THIS_MODULE,
1439 .open = null_open,
1440 .release = null_release,
1441 .report_zones = null_zone_report,
1442 };
1443
1444 static void null_init_queue(struct nullb *nullb, struct nullb_queue *nq)
1445 {
1446 BUG_ON(!nullb);
1447 BUG_ON(!nq);
1448
1449 init_waitqueue_head(&nq->wait);
1450 nq->queue_depth = nullb->queue_depth;
1451 nq->dev = nullb->dev;
1452 }
1453
1454 static void null_init_queues(struct nullb *nullb)
1455 {
1456 struct request_queue *q = nullb->q;
1457 struct blk_mq_hw_ctx *hctx;
1458 struct nullb_queue *nq;
1459 int i;
1460
1461 queue_for_each_hw_ctx(q, hctx, i) {
1462 if (!hctx->nr_ctx || !hctx->tags)
1463 continue;
1464 nq = &nullb->queues[i];
1465 hctx->driver_data = nq;
1466 null_init_queue(nullb, nq);
1467 nullb->nr_queues++;
1468 }
1469 }
1470
1471 static int setup_commands(struct nullb_queue *nq)
1472 {
1473 struct nullb_cmd *cmd;
1474 int i, tag_size;
1475
1476 nq->cmds = kcalloc(nq->queue_depth, sizeof(*cmd), GFP_KERNEL);
1477 if (!nq->cmds)
1478 return -ENOMEM;
1479
1480 tag_size = ALIGN(nq->queue_depth, BITS_PER_LONG) / BITS_PER_LONG;
1481 nq->tag_map = kcalloc(tag_size, sizeof(unsigned long), GFP_KERNEL);
1482 if (!nq->tag_map) {
1483 kfree(nq->cmds);
1484 return -ENOMEM;
1485 }
1486
1487 for (i = 0; i < nq->queue_depth; i++) {
1488 cmd = &nq->cmds[i];
1489 INIT_LIST_HEAD(&cmd->list);
1490 cmd->ll_list.next = NULL;
1491 cmd->tag = -1U;
1492 }
1493
1494 return 0;
1495 }
1496
1497 static int setup_queues(struct nullb *nullb)
1498 {
1499 nullb->queues = kcalloc(nullb->dev->submit_queues,
1500 sizeof(struct nullb_queue),
1501 GFP_KERNEL);
1502 if (!nullb->queues)
1503 return -ENOMEM;
1504
1505 nullb->queue_depth = nullb->dev->hw_queue_depth;
1506
1507 return 0;
1508 }
1509
1510 static int init_driver_queues(struct nullb *nullb)
1511 {
1512 struct nullb_queue *nq;
1513 int i, ret = 0;
1514
1515 for (i = 0; i < nullb->dev->submit_queues; i++) {
1516 nq = &nullb->queues[i];
1517
1518 null_init_queue(nullb, nq);
1519
1520 ret = setup_commands(nq);
1521 if (ret)
1522 return ret;
1523 nullb->nr_queues++;
1524 }
1525 return 0;
1526 }
1527
1528 static int null_gendisk_register(struct nullb *nullb)
1529 {
1530 struct gendisk *disk;
1531 sector_t size;
1532
1533 disk = nullb->disk = alloc_disk_node(1, nullb->dev->home_node);
1534 if (!disk)
1535 return -ENOMEM;
1536 size = (sector_t)nullb->dev->size * 1024 * 1024ULL;
1537 set_capacity(disk, size >> 9);
1538
1539 disk->flags |= GENHD_FL_EXT_DEVT | GENHD_FL_SUPPRESS_PARTITION_INFO;
1540 disk->major = null_major;
1541 disk->first_minor = nullb->index;
1542 disk->fops = &null_fops;
1543 disk->private_data = nullb;
1544 disk->queue = nullb->q;
1545 strncpy(disk->disk_name, nullb->disk_name, DISK_NAME_LEN);
1546
1547 if (nullb->dev->zoned) {
1548 int ret = blk_revalidate_disk_zones(disk);
1549
1550 if (ret != 0)
1551 return ret;
1552 }
1553
1554 add_disk(disk);
1555 return 0;
1556 }
1557
1558 static int null_init_tag_set(struct nullb *nullb, struct blk_mq_tag_set *set)
1559 {
1560 set->ops = &null_mq_ops;
1561 set->nr_hw_queues = nullb ? nullb->dev->submit_queues :
1562 g_submit_queues;
1563 set->queue_depth = nullb ? nullb->dev->hw_queue_depth :
1564 g_hw_queue_depth;
1565 set->numa_node = nullb ? nullb->dev->home_node : g_home_node;
1566 set->cmd_size = sizeof(struct nullb_cmd);
1567 set->flags = BLK_MQ_F_SHOULD_MERGE;
1568 if (g_no_sched)
1569 set->flags |= BLK_MQ_F_NO_SCHED;
1570 set->driver_data = NULL;
1571
1572 if ((nullb && nullb->dev->blocking) || g_blocking)
1573 set->flags |= BLK_MQ_F_BLOCKING;
1574
1575 return blk_mq_alloc_tag_set(set);
1576 }
1577
1578 static void null_validate_conf(struct nullb_device *dev)
1579 {
1580 dev->blocksize = round_down(dev->blocksize, 512);
1581 dev->blocksize = clamp_t(unsigned int, dev->blocksize, 512, 4096);
1582
1583 if (dev->queue_mode == NULL_Q_MQ && dev->use_per_node_hctx) {
1584 if (dev->submit_queues != nr_online_nodes)
1585 dev->submit_queues = nr_online_nodes;
1586 } else if (dev->submit_queues > nr_cpu_ids)
1587 dev->submit_queues = nr_cpu_ids;
1588 else if (dev->submit_queues == 0)
1589 dev->submit_queues = 1;
1590
1591 dev->queue_mode = min_t(unsigned int, dev->queue_mode, NULL_Q_MQ);
1592 dev->irqmode = min_t(unsigned int, dev->irqmode, NULL_IRQ_TIMER);
1593
1594
1595 if (dev->memory_backed)
1596 dev->blocking = true;
1597 else
1598 dev->cache_size = 0;
1599 dev->cache_size = min_t(unsigned long, ULONG_MAX / 1024 / 1024,
1600 dev->cache_size);
1601 dev->mbps = min_t(unsigned int, 1024 * 40, dev->mbps);
1602
1603 if (dev->queue_mode == NULL_Q_BIO)
1604 dev->mbps = 0;
1605 }
1606
1607 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
1608 static bool __null_setup_fault(struct fault_attr *attr, char *str)
1609 {
1610 if (!str[0])
1611 return true;
1612
1613 if (!setup_fault_attr(attr, str))
1614 return false;
1615
1616 attr->verbose = 0;
1617 return true;
1618 }
1619 #endif
1620
1621 static bool null_setup_fault(void)
1622 {
1623 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
1624 if (!__null_setup_fault(&null_timeout_attr, g_timeout_str))
1625 return false;
1626 if (!__null_setup_fault(&null_requeue_attr, g_requeue_str))
1627 return false;
1628 #endif
1629 return true;
1630 }
1631
1632 static int null_add_dev(struct nullb_device *dev)
1633 {
1634 struct nullb *nullb;
1635 int rv;
1636
1637 null_validate_conf(dev);
1638
1639 nullb = kzalloc_node(sizeof(*nullb), GFP_KERNEL, dev->home_node);
1640 if (!nullb) {
1641 rv = -ENOMEM;
1642 goto out;
1643 }
1644 nullb->dev = dev;
1645 dev->nullb = nullb;
1646
1647 spin_lock_init(&nullb->lock);
1648
1649 rv = setup_queues(nullb);
1650 if (rv)
1651 goto out_free_nullb;
1652
1653 if (dev->queue_mode == NULL_Q_MQ) {
1654 if (shared_tags) {
1655 nullb->tag_set = &tag_set;
1656 rv = 0;
1657 } else {
1658 nullb->tag_set = &nullb->__tag_set;
1659 rv = null_init_tag_set(nullb, nullb->tag_set);
1660 }
1661
1662 if (rv)
1663 goto out_cleanup_queues;
1664
1665 if (!null_setup_fault())
1666 goto out_cleanup_queues;
1667
1668 nullb->tag_set->timeout = 5 * HZ;
1669 nullb->q = blk_mq_init_queue(nullb->tag_set);
1670 if (IS_ERR(nullb->q)) {
1671 rv = -ENOMEM;
1672 goto out_cleanup_tags;
1673 }
1674 null_init_queues(nullb);
1675 } else if (dev->queue_mode == NULL_Q_BIO) {
1676 nullb->q = blk_alloc_queue_node(GFP_KERNEL, dev->home_node);
1677 if (!nullb->q) {
1678 rv = -ENOMEM;
1679 goto out_cleanup_queues;
1680 }
1681 blk_queue_make_request(nullb->q, null_queue_bio);
1682 rv = init_driver_queues(nullb);
1683 if (rv)
1684 goto out_cleanup_blk_queue;
1685 }
1686
1687 if (dev->mbps) {
1688 set_bit(NULLB_DEV_FL_THROTTLED, &dev->flags);
1689 nullb_setup_bwtimer(nullb);
1690 }
1691
1692 if (dev->cache_size > 0) {
1693 set_bit(NULLB_DEV_FL_CACHE, &nullb->dev->flags);
1694 blk_queue_write_cache(nullb->q, true, true);
1695 }
1696
1697 if (dev->zoned) {
1698 rv = null_zone_init(dev);
1699 if (rv)
1700 goto out_cleanup_blk_queue;
1701
1702 blk_queue_chunk_sectors(nullb->q, dev->zone_size_sects);
1703 nullb->q->limits.zoned = BLK_ZONED_HM;
1704 blk_queue_flag_set(QUEUE_FLAG_ZONE_RESETALL, nullb->q);
1705 blk_queue_required_elevator_features(nullb->q,
1706 ELEVATOR_F_ZBD_SEQ_WRITE);
1707 }
1708
1709 nullb->q->queuedata = nullb;
1710 blk_queue_flag_set(QUEUE_FLAG_NONROT, nullb->q);
1711 blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, nullb->q);
1712
1713 mutex_lock(&lock);
1714 nullb->index = ida_simple_get(&nullb_indexes, 0, 0, GFP_KERNEL);
1715 dev->index = nullb->index;
1716 mutex_unlock(&lock);
1717
1718 blk_queue_logical_block_size(nullb->q, dev->blocksize);
1719 blk_queue_physical_block_size(nullb->q, dev->blocksize);
1720
1721 null_config_discard(nullb);
1722
1723 sprintf(nullb->disk_name, "nullb%d", nullb->index);
1724
1725 rv = null_gendisk_register(nullb);
1726 if (rv)
1727 goto out_cleanup_zone;
1728
1729 mutex_lock(&lock);
1730 list_add_tail(&nullb->list, &nullb_list);
1731 mutex_unlock(&lock);
1732
1733 return 0;
1734 out_cleanup_zone:
1735 if (dev->zoned)
1736 null_zone_exit(dev);
1737 out_cleanup_blk_queue:
1738 blk_cleanup_queue(nullb->q);
1739 out_cleanup_tags:
1740 if (dev->queue_mode == NULL_Q_MQ && nullb->tag_set == &nullb->__tag_set)
1741 blk_mq_free_tag_set(nullb->tag_set);
1742 out_cleanup_queues:
1743 cleanup_queues(nullb);
1744 out_free_nullb:
1745 kfree(nullb);
1746 dev->nullb = NULL;
1747 out:
1748 return rv;
1749 }
1750
1751 static int __init null_init(void)
1752 {
1753 int ret = 0;
1754 unsigned int i;
1755 struct nullb *nullb;
1756 struct nullb_device *dev;
1757
1758 if (g_bs > PAGE_SIZE) {
1759 pr_warn("invalid block size\n");
1760 pr_warn("defaults block size to %lu\n", PAGE_SIZE);
1761 g_bs = PAGE_SIZE;
1762 }
1763
1764 if (!is_power_of_2(g_zone_size)) {
1765 pr_err("zone_size must be power-of-two\n");
1766 return -EINVAL;
1767 }
1768
1769 if (g_home_node != NUMA_NO_NODE && g_home_node >= nr_online_nodes) {
1770 pr_err("invalid home_node value\n");
1771 g_home_node = NUMA_NO_NODE;
1772 }
1773
1774 if (g_queue_mode == NULL_Q_RQ) {
1775 pr_err("legacy IO path no longer available\n");
1776 return -EINVAL;
1777 }
1778 if (g_queue_mode == NULL_Q_MQ && g_use_per_node_hctx) {
1779 if (g_submit_queues != nr_online_nodes) {
1780 pr_warn("submit_queues param is set to %u.\n",
1781 nr_online_nodes);
1782 g_submit_queues = nr_online_nodes;
1783 }
1784 } else if (g_submit_queues > nr_cpu_ids)
1785 g_submit_queues = nr_cpu_ids;
1786 else if (g_submit_queues <= 0)
1787 g_submit_queues = 1;
1788
1789 if (g_queue_mode == NULL_Q_MQ && shared_tags) {
1790 ret = null_init_tag_set(NULL, &tag_set);
1791 if (ret)
1792 return ret;
1793 }
1794
1795 config_group_init(&nullb_subsys.su_group);
1796 mutex_init(&nullb_subsys.su_mutex);
1797
1798 ret = configfs_register_subsystem(&nullb_subsys);
1799 if (ret)
1800 goto err_tagset;
1801
1802 mutex_init(&lock);
1803
1804 null_major = register_blkdev(0, "nullb");
1805 if (null_major < 0) {
1806 ret = null_major;
1807 goto err_conf;
1808 }
1809
1810 for (i = 0; i < nr_devices; i++) {
1811 dev = null_alloc_dev();
1812 if (!dev) {
1813 ret = -ENOMEM;
1814 goto err_dev;
1815 }
1816 ret = null_add_dev(dev);
1817 if (ret) {
1818 null_free_dev(dev);
1819 goto err_dev;
1820 }
1821 }
1822
1823 pr_info("module loaded\n");
1824 return 0;
1825
1826 err_dev:
1827 while (!list_empty(&nullb_list)) {
1828 nullb = list_entry(nullb_list.next, struct nullb, list);
1829 dev = nullb->dev;
1830 null_del_dev(nullb);
1831 null_free_dev(dev);
1832 }
1833 unregister_blkdev(null_major, "nullb");
1834 err_conf:
1835 configfs_unregister_subsystem(&nullb_subsys);
1836 err_tagset:
1837 if (g_queue_mode == NULL_Q_MQ && shared_tags)
1838 blk_mq_free_tag_set(&tag_set);
1839 return ret;
1840 }
1841
1842 static void __exit null_exit(void)
1843 {
1844 struct nullb *nullb;
1845
1846 configfs_unregister_subsystem(&nullb_subsys);
1847
1848 unregister_blkdev(null_major, "nullb");
1849
1850 mutex_lock(&lock);
1851 while (!list_empty(&nullb_list)) {
1852 struct nullb_device *dev;
1853
1854 nullb = list_entry(nullb_list.next, struct nullb, list);
1855 dev = nullb->dev;
1856 null_del_dev(nullb);
1857 null_free_dev(dev);
1858 }
1859 mutex_unlock(&lock);
1860
1861 if (g_queue_mode == NULL_Q_MQ && shared_tags)
1862 blk_mq_free_tag_set(&tag_set);
1863 }
1864
1865 module_init(null_init);
1866 module_exit(null_exit);
1867
1868 MODULE_AUTHOR("Jens Axboe <axboe@kernel.dk>");
1869 MODULE_LICENSE("GPL");