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
24static DECLARE_FAULT_ATTR(null_timeout_attr);
25static DECLARE_FAULT_ATTR(null_requeue_attr);
26#endif
27
28static 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
41enum 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
61struct 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
68static LIST_HEAD(nullb_list);
69static struct mutex lock;
70static int null_major;
71static DEFINE_IDA(nullb_indexes);
72static struct blk_mq_tag_set tag_set;
73
74enum {
75 NULL_IRQ_NONE = 0,
76 NULL_IRQ_SOFTIRQ = 1,
77 NULL_IRQ_TIMER = 2,
78};
79
80enum {
81 NULL_Q_BIO = 0,
82 NULL_Q_RQ = 1,
83 NULL_Q_MQ = 2,
84};
85
86static int g_no_sched;
87module_param_named(no_sched, g_no_sched, int, 0444);
88MODULE_PARM_DESC(no_sched, "No io scheduler");
89
90static int g_submit_queues = 1;
91module_param_named(submit_queues, g_submit_queues, int, 0444);
92MODULE_PARM_DESC(submit_queues, "Number of submission queues");
93
94static int g_home_node = NUMA_NO_NODE;
95module_param_named(home_node, g_home_node, int, 0444);
96MODULE_PARM_DESC(home_node, "Home node for the device");
97
98#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
99static char g_timeout_str[80];
100module_param_string(timeout, g_timeout_str, sizeof(g_timeout_str), 0444);
101
102static char g_requeue_str[80];
103module_param_string(requeue, g_requeue_str, sizeof(g_requeue_str), 0444);
104#endif
105
106static int g_queue_mode = NULL_Q_MQ;
107
108static 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
123static 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
128static const struct kernel_param_ops null_queue_mode_param_ops = {
129 .set = null_set_queue_mode,
130 .get = param_get_int,
131};
132
133device_param_cb(queue_mode, &null_queue_mode_param_ops, &g_queue_mode, 0444);
134MODULE_PARM_DESC(queue_mode, "Block interface to use (0=bio,1=rq,2=multiqueue)");
135
136static int g_gb = 250;
137module_param_named(gb, g_gb, int, 0444);
138MODULE_PARM_DESC(gb, "Size in GB");
139
140static int g_bs = 512;
141module_param_named(bs, g_bs, int, 0444);
142MODULE_PARM_DESC(bs, "Block size (in bytes)");
143
144static int nr_devices = 1;
145module_param(nr_devices, int, 0444);
146MODULE_PARM_DESC(nr_devices, "Number of devices to register");
147
148static bool g_blocking;
149module_param_named(blocking, g_blocking, bool, 0444);
150MODULE_PARM_DESC(blocking, "Register as a blocking blk-mq driver device");
151
152static bool shared_tags;
153module_param(shared_tags, bool, 0444);
154MODULE_PARM_DESC(shared_tags, "Share tag set between devices for blk-mq");
155
156static int g_irqmode = NULL_IRQ_SOFTIRQ;
157
158static 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
164static const struct kernel_param_ops null_irqmode_param_ops = {
165 .set = null_set_irqmode,
166 .get = param_get_int,
167};
168
169device_param_cb(irqmode, &null_irqmode_param_ops, &g_irqmode, 0444);
170MODULE_PARM_DESC(irqmode, "IRQ completion handler. 0-none, 1-softirq, 2-timer");
171
172static unsigned long g_completion_nsec = 10000;
173module_param_named(completion_nsec, g_completion_nsec, ulong, 0444);
174MODULE_PARM_DESC(completion_nsec, "Time in ns to complete a request in hardware. Default: 10,000ns");
175
176static int g_hw_queue_depth = 64;
177module_param_named(hw_queue_depth, g_hw_queue_depth, int, 0444);
178MODULE_PARM_DESC(hw_queue_depth, "Queue depth for each hardware queue. Default: 64");
179
180static bool g_use_per_node_hctx;
181module_param_named(use_per_node_hctx, g_use_per_node_hctx, bool, 0444);
182MODULE_PARM_DESC(use_per_node_hctx, "Use per-node allocation for hardware context queues. Default: false");
183
184static bool g_zoned;
185module_param_named(zoned, g_zoned, bool, S_IRUGO);
186MODULE_PARM_DESC(zoned, "Make device as a host-managed zoned block device. Default: false");
187
188static unsigned long g_zone_size = 256;
189module_param_named(zone_size, g_zone_size, ulong, S_IRUGO);
190MODULE_PARM_DESC(zone_size, "Zone size in MB when block device is zoned. Must be power-of-two: Default: 256");
191
192static unsigned int g_zone_nr_conv;
193module_param_named(zone_nr_conv, g_zone_nr_conv, uint, 0444);
194MODULE_PARM_DESC(zone_nr_conv, "Number of conventional zones when block device is zoned. Default: 0");
195
196static struct nullb_device *null_alloc_dev(void);
197static void null_free_dev(struct nullb_device *dev);
198static void null_del_dev(struct nullb *nullb);
199static int null_add_dev(struct nullb_device *dev);
200static void null_free_device_storage(struct nullb_device *dev, bool is_cache);
201
202static 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
207static 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
212static 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
218static inline ssize_t nullb_device_bool_attr_show(bool val, char *page)
219{
220 return snprintf(page, PAGE_SIZE, "%u\n", val);
221}
222
223static 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
237static 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
251static 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) \
267static ssize_t \
268nullb_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} \
273static ssize_t \
274nullb_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} \
282CONFIGFS_ATTR(nullb_device_, NAME);
283
284NULLB_DEVICE_ATTR(size, ulong);
285NULLB_DEVICE_ATTR(completion_nsec, ulong);
286NULLB_DEVICE_ATTR(submit_queues, uint);
287NULLB_DEVICE_ATTR(home_node, uint);
288NULLB_DEVICE_ATTR(queue_mode, uint);
289NULLB_DEVICE_ATTR(blocksize, uint);
290NULLB_DEVICE_ATTR(irqmode, uint);
291NULLB_DEVICE_ATTR(hw_queue_depth, uint);
292NULLB_DEVICE_ATTR(index, uint);
293NULLB_DEVICE_ATTR(blocking, bool);
294NULLB_DEVICE_ATTR(use_per_node_hctx, bool);
295NULLB_DEVICE_ATTR(memory_backed, bool);
296NULLB_DEVICE_ATTR(discard, bool);
297NULLB_DEVICE_ATTR(mbps, uint);
298NULLB_DEVICE_ATTR(cache_size, ulong);
299NULLB_DEVICE_ATTR(zoned, bool);
300NULLB_DEVICE_ATTR(zone_size, ulong);
301NULLB_DEVICE_ATTR(zone_nr_conv, uint);
302
303static 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
308static 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
342CONFIGFS_ATTR(nullb_device_, power);
343
344static 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
351static 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;
391out:
392 kfree(orig);
393 return ret;
394}
395CONFIGFS_ATTR(nullb_device_, badblocks);
396
397static 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
421static 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
429static struct configfs_item_operations nullb_device_ops = {
430 .release = nullb_device_release,
431};
432
433static 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
439static struct
440config_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
453static void
454nullb_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
468static 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
473CONFIGFS_ATTR_RO(memb_group_, features);
474
475static struct configfs_attribute *nullb_group_attrs[] = {
476 &memb_group_attr_features,
477 NULL,
478};
479
480static struct configfs_group_operations nullb_group_ops = {
481 .make_item = nullb_group_make_item,
482 .drop_item = nullb_group_drop_item,
483};
484
485static 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
491static 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
500static inline int null_cache_active(struct nullb *nullb)
501{
502 return test_bit(NULLB_DEV_FL_CACHE, &nullb->dev->flags);
503}
504
505static 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
535static 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
545static 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
553static 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
566static void free_cmd(struct nullb_cmd *cmd)
567{
568 put_tag(cmd->nq, cmd->tag);
569}
570
571static enum hrtimer_restart null_cmd_timer_expired(struct hrtimer *timer);
572
573static 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->nq = nq;
583 if (nq->dev->irqmode == NULL_IRQ_TIMER) {
584 hrtimer_init(&cmd->timer, CLOCK_MONOTONIC,
585 HRTIMER_MODE_REL);
586 cmd->timer.function = null_cmd_timer_expired;
587 }
588 return cmd;
589 }
590
591 return NULL;
592}
593
594static struct nullb_cmd *alloc_cmd(struct nullb_queue *nq, int can_wait)
595{
596 struct nullb_cmd *cmd;
597 DEFINE_WAIT(wait);
598
599 cmd = __alloc_cmd(nq);
600 if (cmd || !can_wait)
601 return cmd;
602
603 do {
604 prepare_to_wait(&nq->wait, &wait, TASK_UNINTERRUPTIBLE);
605 cmd = __alloc_cmd(nq);
606 if (cmd)
607 break;
608
609 io_schedule();
610 } while (1);
611
612 finish_wait(&nq->wait, &wait);
613 return cmd;
614}
615
616static void end_cmd(struct nullb_cmd *cmd)
617{
618 int queue_mode = cmd->nq->dev->queue_mode;
619
620 switch (queue_mode) {
621 case NULL_Q_MQ:
622 blk_mq_end_request(cmd->rq, cmd->error);
623 return;
624 case NULL_Q_BIO:
625 cmd->bio->bi_status = cmd->error;
626 bio_endio(cmd->bio);
627 break;
628 }
629
630 free_cmd(cmd);
631}
632
633static enum hrtimer_restart null_cmd_timer_expired(struct hrtimer *timer)
634{
635 end_cmd(container_of(timer, struct nullb_cmd, timer));
636
637 return HRTIMER_NORESTART;
638}
639
640static void null_cmd_end_timer(struct nullb_cmd *cmd)
641{
642 ktime_t kt = cmd->nq->dev->completion_nsec;
643
644 hrtimer_start(&cmd->timer, kt, HRTIMER_MODE_REL);
645}
646
647static void null_complete_rq(struct request *rq)
648{
649 end_cmd(blk_mq_rq_to_pdu(rq));
650}
651
652static struct nullb_page *null_alloc_page(gfp_t gfp_flags)
653{
654 struct nullb_page *t_page;
655
656 t_page = kmalloc(sizeof(struct nullb_page), gfp_flags);
657 if (!t_page)
658 goto out;
659
660 t_page->page = alloc_pages(gfp_flags, 0);
661 if (!t_page->page)
662 goto out_freepage;
663
664 memset(t_page->bitmap, 0, sizeof(t_page->bitmap));
665 return t_page;
666out_freepage:
667 kfree(t_page);
668out:
669 return NULL;
670}
671
672static void null_free_page(struct nullb_page *t_page)
673{
674 __set_bit(NULLB_PAGE_FREE, t_page->bitmap);
675 if (test_bit(NULLB_PAGE_LOCK, t_page->bitmap))
676 return;
677 __free_page(t_page->page);
678 kfree(t_page);
679}
680
681static bool null_page_empty(struct nullb_page *page)
682{
683 int size = MAP_SZ - 2;
684
685 return find_first_bit(page->bitmap, size) == size;
686}
687
688static void null_free_sector(struct nullb *nullb, sector_t sector,
689 bool is_cache)
690{
691 unsigned int sector_bit;
692 u64 idx;
693 struct nullb_page *t_page, *ret;
694 struct radix_tree_root *root;
695
696 root = is_cache ? &nullb->dev->cache : &nullb->dev->data;
697 idx = sector >> PAGE_SECTORS_SHIFT;
698 sector_bit = (sector & SECTOR_MASK);
699
700 t_page = radix_tree_lookup(root, idx);
701 if (t_page) {
702 __clear_bit(sector_bit, t_page->bitmap);
703
704 if (null_page_empty(t_page)) {
705 ret = radix_tree_delete_item(root, idx, t_page);
706 WARN_ON(ret != t_page);
707 null_free_page(ret);
708 if (is_cache)
709 nullb->dev->curr_cache -= PAGE_SIZE;
710 }
711 }
712}
713
714static struct nullb_page *null_radix_tree_insert(struct nullb *nullb, u64 idx,
715 struct nullb_page *t_page, bool is_cache)
716{
717 struct radix_tree_root *root;
718
719 root = is_cache ? &nullb->dev->cache : &nullb->dev->data;
720
721 if (radix_tree_insert(root, idx, t_page)) {
722 null_free_page(t_page);
723 t_page = radix_tree_lookup(root, idx);
724 WARN_ON(!t_page || t_page->page->index != idx);
725 } else if (is_cache)
726 nullb->dev->curr_cache += PAGE_SIZE;
727
728 return t_page;
729}
730
731static void null_free_device_storage(struct nullb_device *dev, bool is_cache)
732{
733 unsigned long pos = 0;
734 int nr_pages;
735 struct nullb_page *ret, *t_pages[FREE_BATCH];
736 struct radix_tree_root *root;
737
738 root = is_cache ? &dev->cache : &dev->data;
739
740 do {
741 int i;
742
743 nr_pages = radix_tree_gang_lookup(root,
744 (void **)t_pages, pos, FREE_BATCH);
745
746 for (i = 0; i < nr_pages; i++) {
747 pos = t_pages[i]->page->index;
748 ret = radix_tree_delete_item(root, pos, t_pages[i]);
749 WARN_ON(ret != t_pages[i]);
750 null_free_page(ret);
751 }
752
753 pos++;
754 } while (nr_pages == FREE_BATCH);
755
756 if (is_cache)
757 dev->curr_cache = 0;
758}
759
760static struct nullb_page *__null_lookup_page(struct nullb *nullb,
761 sector_t sector, bool for_write, bool is_cache)
762{
763 unsigned int sector_bit;
764 u64 idx;
765 struct nullb_page *t_page;
766 struct radix_tree_root *root;
767
768 idx = sector >> PAGE_SECTORS_SHIFT;
769 sector_bit = (sector & SECTOR_MASK);
770
771 root = is_cache ? &nullb->dev->cache : &nullb->dev->data;
772 t_page = radix_tree_lookup(root, idx);
773 WARN_ON(t_page && t_page->page->index != idx);
774
775 if (t_page && (for_write || test_bit(sector_bit, t_page->bitmap)))
776 return t_page;
777
778 return NULL;
779}
780
781static struct nullb_page *null_lookup_page(struct nullb *nullb,
782 sector_t sector, bool for_write, bool ignore_cache)
783{
784 struct nullb_page *page = NULL;
785
786 if (!ignore_cache)
787 page = __null_lookup_page(nullb, sector, for_write, true);
788 if (page)
789 return page;
790 return __null_lookup_page(nullb, sector, for_write, false);
791}
792
793static struct nullb_page *null_insert_page(struct nullb *nullb,
794 sector_t sector, bool ignore_cache)
795 __releases(&nullb->lock)
796 __acquires(&nullb->lock)
797{
798 u64 idx;
799 struct nullb_page *t_page;
800
801 t_page = null_lookup_page(nullb, sector, true, ignore_cache);
802 if (t_page)
803 return t_page;
804
805 spin_unlock_irq(&nullb->lock);
806
807 t_page = null_alloc_page(GFP_NOIO);
808 if (!t_page)
809 goto out_lock;
810
811 if (radix_tree_preload(GFP_NOIO))
812 goto out_freepage;
813
814 spin_lock_irq(&nullb->lock);
815 idx = sector >> PAGE_SECTORS_SHIFT;
816 t_page->page->index = idx;
817 t_page = null_radix_tree_insert(nullb, idx, t_page, !ignore_cache);
818 radix_tree_preload_end();
819
820 return t_page;
821out_freepage:
822 null_free_page(t_page);
823out_lock:
824 spin_lock_irq(&nullb->lock);
825 return null_lookup_page(nullb, sector, true, ignore_cache);
826}
827
828static int null_flush_cache_page(struct nullb *nullb, struct nullb_page *c_page)
829{
830 int i;
831 unsigned int offset;
832 u64 idx;
833 struct nullb_page *t_page, *ret;
834 void *dst, *src;
835
836 idx = c_page->page->index;
837
838 t_page = null_insert_page(nullb, idx << PAGE_SECTORS_SHIFT, true);
839
840 __clear_bit(NULLB_PAGE_LOCK, c_page->bitmap);
841 if (test_bit(NULLB_PAGE_FREE, c_page->bitmap)) {
842 null_free_page(c_page);
843 if (t_page && null_page_empty(t_page)) {
844 ret = radix_tree_delete_item(&nullb->dev->data,
845 idx, t_page);
846 null_free_page(t_page);
847 }
848 return 0;
849 }
850
851 if (!t_page)
852 return -ENOMEM;
853
854 src = kmap_atomic(c_page->page);
855 dst = kmap_atomic(t_page->page);
856
857 for (i = 0; i < PAGE_SECTORS;
858 i += (nullb->dev->blocksize >> SECTOR_SHIFT)) {
859 if (test_bit(i, c_page->bitmap)) {
860 offset = (i << SECTOR_SHIFT);
861 memcpy(dst + offset, src + offset,
862 nullb->dev->blocksize);
863 __set_bit(i, t_page->bitmap);
864 }
865 }
866
867 kunmap_atomic(dst);
868 kunmap_atomic(src);
869
870 ret = radix_tree_delete_item(&nullb->dev->cache, idx, c_page);
871 null_free_page(ret);
872 nullb->dev->curr_cache -= PAGE_SIZE;
873
874 return 0;
875}
876
877static int null_make_cache_space(struct nullb *nullb, unsigned long n)
878{
879 int i, err, nr_pages;
880 struct nullb_page *c_pages[FREE_BATCH];
881 unsigned long flushed = 0, one_round;
882
883again:
884 if ((nullb->dev->cache_size * 1024 * 1024) >
885 nullb->dev->curr_cache + n || nullb->dev->curr_cache == 0)
886 return 0;
887
888 nr_pages = radix_tree_gang_lookup(&nullb->dev->cache,
889 (void **)c_pages, nullb->cache_flush_pos, FREE_BATCH);
890
891
892
893
894 for (i = 0; i < nr_pages; i++) {
895 nullb->cache_flush_pos = c_pages[i]->page->index;
896
897
898
899
900 if (test_bit(NULLB_PAGE_LOCK, c_pages[i]->bitmap))
901 c_pages[i] = NULL;
902 else
903 __set_bit(NULLB_PAGE_LOCK, c_pages[i]->bitmap);
904 }
905
906 one_round = 0;
907 for (i = 0; i < nr_pages; i++) {
908 if (c_pages[i] == NULL)
909 continue;
910 err = null_flush_cache_page(nullb, c_pages[i]);
911 if (err)
912 return err;
913 one_round++;
914 }
915 flushed += one_round << PAGE_SHIFT;
916
917 if (n > flushed) {
918 if (nr_pages == 0)
919 nullb->cache_flush_pos = 0;
920 if (one_round == 0) {
921
922 spin_unlock_irq(&nullb->lock);
923 spin_lock_irq(&nullb->lock);
924 }
925 goto again;
926 }
927 return 0;
928}
929
930static int copy_to_nullb(struct nullb *nullb, struct page *source,
931 unsigned int off, sector_t sector, size_t n, bool is_fua)
932{
933 size_t temp, count = 0;
934 unsigned int offset;
935 struct nullb_page *t_page;
936 void *dst, *src;
937
938 while (count < n) {
939 temp = min_t(size_t, nullb->dev->blocksize, n - count);
940
941 if (null_cache_active(nullb) && !is_fua)
942 null_make_cache_space(nullb, PAGE_SIZE);
943
944 offset = (sector & SECTOR_MASK) << SECTOR_SHIFT;
945 t_page = null_insert_page(nullb, sector,
946 !null_cache_active(nullb) || is_fua);
947 if (!t_page)
948 return -ENOSPC;
949
950 src = kmap_atomic(source);
951 dst = kmap_atomic(t_page->page);
952 memcpy(dst + offset, src + off + count, temp);
953 kunmap_atomic(dst);
954 kunmap_atomic(src);
955
956 __set_bit(sector & SECTOR_MASK, t_page->bitmap);
957
958 if (is_fua)
959 null_free_sector(nullb, sector, true);
960
961 count += temp;
962 sector += temp >> SECTOR_SHIFT;
963 }
964 return 0;
965}
966
967static int copy_from_nullb(struct nullb *nullb, struct page *dest,
968 unsigned int off, sector_t sector, size_t n)
969{
970 size_t temp, count = 0;
971 unsigned int offset;
972 struct nullb_page *t_page;
973 void *dst, *src;
974
975 while (count < n) {
976 temp = min_t(size_t, nullb->dev->blocksize, n - count);
977
978 offset = (sector & SECTOR_MASK) << SECTOR_SHIFT;
979 t_page = null_lookup_page(nullb, sector, false,
980 !null_cache_active(nullb));
981
982 dst = kmap_atomic(dest);
983 if (!t_page) {
984 memset(dst + off + count, 0, temp);
985 goto next;
986 }
987 src = kmap_atomic(t_page->page);
988 memcpy(dst + off + count, src + offset, temp);
989 kunmap_atomic(src);
990next:
991 kunmap_atomic(dst);
992
993 count += temp;
994 sector += temp >> SECTOR_SHIFT;
995 }
996 return 0;
997}
998
999static void null_handle_discard(struct nullb *nullb, sector_t sector, size_t n)
1000{
1001 size_t temp;
1002
1003 spin_lock_irq(&nullb->lock);
1004 while (n > 0) {
1005 temp = min_t(size_t, n, nullb->dev->blocksize);
1006 null_free_sector(nullb, sector, false);
1007 if (null_cache_active(nullb))
1008 null_free_sector(nullb, sector, true);
1009 sector += temp >> SECTOR_SHIFT;
1010 n -= temp;
1011 }
1012 spin_unlock_irq(&nullb->lock);
1013}
1014
1015static int null_handle_flush(struct nullb *nullb)
1016{
1017 int err;
1018
1019 if (!null_cache_active(nullb))
1020 return 0;
1021
1022 spin_lock_irq(&nullb->lock);
1023 while (true) {
1024 err = null_make_cache_space(nullb,
1025 nullb->dev->cache_size * 1024 * 1024);
1026 if (err || nullb->dev->curr_cache == 0)
1027 break;
1028 }
1029
1030 WARN_ON(!radix_tree_empty(&nullb->dev->cache));
1031 spin_unlock_irq(&nullb->lock);
1032 return err;
1033}
1034
1035static int null_transfer(struct nullb *nullb, struct page *page,
1036 unsigned int len, unsigned int off, bool is_write, sector_t sector,
1037 bool is_fua)
1038{
1039 int err = 0;
1040
1041 if (!is_write) {
1042 err = copy_from_nullb(nullb, page, off, sector, len);
1043 flush_dcache_page(page);
1044 } else {
1045 flush_dcache_page(page);
1046 err = copy_to_nullb(nullb, page, off, sector, len, is_fua);
1047 }
1048
1049 return err;
1050}
1051
1052static int null_handle_rq(struct nullb_cmd *cmd)
1053{
1054 struct request *rq = cmd->rq;
1055 struct nullb *nullb = cmd->nq->dev->nullb;
1056 int err;
1057 unsigned int len;
1058 sector_t sector;
1059 struct req_iterator iter;
1060 struct bio_vec bvec;
1061
1062 sector = blk_rq_pos(rq);
1063
1064 if (req_op(rq) == REQ_OP_DISCARD) {
1065 null_handle_discard(nullb, sector, blk_rq_bytes(rq));
1066 return 0;
1067 }
1068
1069 spin_lock_irq(&nullb->lock);
1070 rq_for_each_segment(bvec, rq, iter) {
1071 len = bvec.bv_len;
1072 err = null_transfer(nullb, bvec.bv_page, len, bvec.bv_offset,
1073 op_is_write(req_op(rq)), sector,
1074 req_op(rq) & REQ_FUA);
1075 if (err) {
1076 spin_unlock_irq(&nullb->lock);
1077 return err;
1078 }
1079 sector += len >> SECTOR_SHIFT;
1080 }
1081 spin_unlock_irq(&nullb->lock);
1082
1083 return 0;
1084}
1085
1086static int null_handle_bio(struct nullb_cmd *cmd)
1087{
1088 struct bio *bio = cmd->bio;
1089 struct nullb *nullb = cmd->nq->dev->nullb;
1090 int err;
1091 unsigned int len;
1092 sector_t sector;
1093 struct bio_vec bvec;
1094 struct bvec_iter iter;
1095
1096 sector = bio->bi_iter.bi_sector;
1097
1098 if (bio_op(bio) == REQ_OP_DISCARD) {
1099 null_handle_discard(nullb, sector,
1100 bio_sectors(bio) << SECTOR_SHIFT);
1101 return 0;
1102 }
1103
1104 spin_lock_irq(&nullb->lock);
1105 bio_for_each_segment(bvec, bio, iter) {
1106 len = bvec.bv_len;
1107 err = null_transfer(nullb, bvec.bv_page, len, bvec.bv_offset,
1108 op_is_write(bio_op(bio)), sector,
1109 bio->bi_opf & REQ_FUA);
1110 if (err) {
1111 spin_unlock_irq(&nullb->lock);
1112 return err;
1113 }
1114 sector += len >> SECTOR_SHIFT;
1115 }
1116 spin_unlock_irq(&nullb->lock);
1117 return 0;
1118}
1119
1120static void null_stop_queue(struct nullb *nullb)
1121{
1122 struct request_queue *q = nullb->q;
1123
1124 if (nullb->dev->queue_mode == NULL_Q_MQ)
1125 blk_mq_stop_hw_queues(q);
1126}
1127
1128static void null_restart_queue_async(struct nullb *nullb)
1129{
1130 struct request_queue *q = nullb->q;
1131
1132 if (nullb->dev->queue_mode == NULL_Q_MQ)
1133 blk_mq_start_stopped_hw_queues(q, true);
1134}
1135
1136static blk_status_t null_handle_cmd(struct nullb_cmd *cmd)
1137{
1138 struct nullb_device *dev = cmd->nq->dev;
1139 struct nullb *nullb = dev->nullb;
1140 int err = 0;
1141
1142 if (test_bit(NULLB_DEV_FL_THROTTLED, &dev->flags)) {
1143 struct request *rq = cmd->rq;
1144
1145 if (!hrtimer_active(&nullb->bw_timer))
1146 hrtimer_restart(&nullb->bw_timer);
1147
1148 if (atomic_long_sub_return(blk_rq_bytes(rq),
1149 &nullb->cur_bytes) < 0) {
1150 null_stop_queue(nullb);
1151
1152 if (atomic_long_read(&nullb->cur_bytes) > 0)
1153 null_restart_queue_async(nullb);
1154
1155 return BLK_STS_DEV_RESOURCE;
1156 }
1157 }
1158
1159 if (nullb->dev->badblocks.shift != -1) {
1160 int bad_sectors;
1161 sector_t sector, size, first_bad;
1162 bool is_flush = true;
1163
1164 if (dev->queue_mode == NULL_Q_BIO &&
1165 bio_op(cmd->bio) != REQ_OP_FLUSH) {
1166 is_flush = false;
1167 sector = cmd->bio->bi_iter.bi_sector;
1168 size = bio_sectors(cmd->bio);
1169 }
1170 if (dev->queue_mode != NULL_Q_BIO &&
1171 req_op(cmd->rq) != REQ_OP_FLUSH) {
1172 is_flush = false;
1173 sector = blk_rq_pos(cmd->rq);
1174 size = blk_rq_sectors(cmd->rq);
1175 }
1176 if (!is_flush && badblocks_check(&nullb->dev->badblocks, sector,
1177 size, &first_bad, &bad_sectors)) {
1178 cmd->error = BLK_STS_IOERR;
1179 goto out;
1180 }
1181 }
1182
1183 if (dev->memory_backed) {
1184 if (dev->queue_mode == NULL_Q_BIO) {
1185 if (bio_op(cmd->bio) == REQ_OP_FLUSH)
1186 err = null_handle_flush(nullb);
1187 else
1188 err = null_handle_bio(cmd);
1189 } else {
1190 if (req_op(cmd->rq) == REQ_OP_FLUSH)
1191 err = null_handle_flush(nullb);
1192 else
1193 err = null_handle_rq(cmd);
1194 }
1195 }
1196 cmd->error = errno_to_blk_status(err);
1197
1198 if (!cmd->error && dev->zoned) {
1199 sector_t sector;
1200 unsigned int nr_sectors;
1201 enum req_opf op;
1202
1203 if (dev->queue_mode == NULL_Q_BIO) {
1204 op = bio_op(cmd->bio);
1205 sector = cmd->bio->bi_iter.bi_sector;
1206 nr_sectors = cmd->bio->bi_iter.bi_size >> 9;
1207 } else {
1208 op = req_op(cmd->rq);
1209 sector = blk_rq_pos(cmd->rq);
1210 nr_sectors = blk_rq_sectors(cmd->rq);
1211 }
1212
1213 if (op == REQ_OP_WRITE)
1214 null_zone_write(cmd, sector, nr_sectors);
1215 else if (op == REQ_OP_ZONE_RESET)
1216 null_zone_reset(cmd, sector);
1217 }
1218out:
1219
1220 switch (dev->irqmode) {
1221 case NULL_IRQ_SOFTIRQ:
1222 switch (dev->queue_mode) {
1223 case NULL_Q_MQ:
1224 blk_mq_complete_request(cmd->rq);
1225 break;
1226 case NULL_Q_BIO:
1227
1228
1229
1230 end_cmd(cmd);
1231 break;
1232 }
1233 break;
1234 case NULL_IRQ_NONE:
1235 end_cmd(cmd);
1236 break;
1237 case NULL_IRQ_TIMER:
1238 null_cmd_end_timer(cmd);
1239 break;
1240 }
1241 return BLK_STS_OK;
1242}
1243
1244static enum hrtimer_restart nullb_bwtimer_fn(struct hrtimer *timer)
1245{
1246 struct nullb *nullb = container_of(timer, struct nullb, bw_timer);
1247 ktime_t timer_interval = ktime_set(0, TIMER_INTERVAL);
1248 unsigned int mbps = nullb->dev->mbps;
1249
1250 if (atomic_long_read(&nullb->cur_bytes) == mb_per_tick(mbps))
1251 return HRTIMER_NORESTART;
1252
1253 atomic_long_set(&nullb->cur_bytes, mb_per_tick(mbps));
1254 null_restart_queue_async(nullb);
1255
1256 hrtimer_forward_now(&nullb->bw_timer, timer_interval);
1257
1258 return HRTIMER_RESTART;
1259}
1260
1261static void nullb_setup_bwtimer(struct nullb *nullb)
1262{
1263 ktime_t timer_interval = ktime_set(0, TIMER_INTERVAL);
1264
1265 hrtimer_init(&nullb->bw_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
1266 nullb->bw_timer.function = nullb_bwtimer_fn;
1267 atomic_long_set(&nullb->cur_bytes, mb_per_tick(nullb->dev->mbps));
1268 hrtimer_start(&nullb->bw_timer, timer_interval, HRTIMER_MODE_REL);
1269}
1270
1271static struct nullb_queue *nullb_to_queue(struct nullb *nullb)
1272{
1273 int index = 0;
1274
1275 if (nullb->nr_queues != 1)
1276 index = raw_smp_processor_id() / ((nr_cpu_ids + nullb->nr_queues - 1) / nullb->nr_queues);
1277
1278 return &nullb->queues[index];
1279}
1280
1281static blk_qc_t null_queue_bio(struct request_queue *q, struct bio *bio)
1282{
1283 struct nullb *nullb = q->queuedata;
1284 struct nullb_queue *nq = nullb_to_queue(nullb);
1285 struct nullb_cmd *cmd;
1286
1287 cmd = alloc_cmd(nq, 1);
1288 cmd->bio = bio;
1289
1290 null_handle_cmd(cmd);
1291 return BLK_QC_T_NONE;
1292}
1293
1294static bool should_timeout_request(struct request *rq)
1295{
1296#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
1297 if (g_timeout_str[0])
1298 return should_fail(&null_timeout_attr, 1);
1299#endif
1300 return false;
1301}
1302
1303static bool should_requeue_request(struct request *rq)
1304{
1305#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
1306 if (g_requeue_str[0])
1307 return should_fail(&null_requeue_attr, 1);
1308#endif
1309 return false;
1310}
1311
1312static enum blk_eh_timer_return null_timeout_rq(struct request *rq, bool res)
1313{
1314 pr_info("null: rq %p timed out\n", rq);
1315 blk_mq_complete_request(rq);
1316 return BLK_EH_DONE;
1317}
1318
1319static blk_status_t null_queue_rq(struct blk_mq_hw_ctx *hctx,
1320 const struct blk_mq_queue_data *bd)
1321{
1322 struct nullb_cmd *cmd = blk_mq_rq_to_pdu(bd->rq);
1323 struct nullb_queue *nq = hctx->driver_data;
1324
1325 might_sleep_if(hctx->flags & BLK_MQ_F_BLOCKING);
1326
1327 if (nq->dev->irqmode == NULL_IRQ_TIMER) {
1328 hrtimer_init(&cmd->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
1329 cmd->timer.function = null_cmd_timer_expired;
1330 }
1331 cmd->rq = bd->rq;
1332 cmd->nq = nq;
1333
1334 blk_mq_start_request(bd->rq);
1335
1336 if (should_requeue_request(bd->rq)) {
1337
1338
1339
1340
1341 nq->requeue_selection++;
1342 if (nq->requeue_selection & 1)
1343 return BLK_STS_RESOURCE;
1344 else {
1345 blk_mq_requeue_request(bd->rq, true);
1346 return BLK_STS_OK;
1347 }
1348 }
1349 if (should_timeout_request(bd->rq))
1350 return BLK_STS_OK;
1351
1352 return null_handle_cmd(cmd);
1353}
1354
1355static const struct blk_mq_ops null_mq_ops = {
1356 .queue_rq = null_queue_rq,
1357 .complete = null_complete_rq,
1358 .timeout = null_timeout_rq,
1359};
1360
1361static void cleanup_queue(struct nullb_queue *nq)
1362{
1363 kfree(nq->tag_map);
1364 kfree(nq->cmds);
1365}
1366
1367static void cleanup_queues(struct nullb *nullb)
1368{
1369 int i;
1370
1371 for (i = 0; i < nullb->nr_queues; i++)
1372 cleanup_queue(&nullb->queues[i]);
1373
1374 kfree(nullb->queues);
1375}
1376
1377static void null_del_dev(struct nullb *nullb)
1378{
1379 struct nullb_device *dev = nullb->dev;
1380
1381 ida_simple_remove(&nullb_indexes, nullb->index);
1382
1383 list_del_init(&nullb->list);
1384
1385 del_gendisk(nullb->disk);
1386
1387 if (test_bit(NULLB_DEV_FL_THROTTLED, &nullb->dev->flags)) {
1388 hrtimer_cancel(&nullb->bw_timer);
1389 atomic_long_set(&nullb->cur_bytes, LONG_MAX);
1390 null_restart_queue_async(nullb);
1391 }
1392
1393 blk_cleanup_queue(nullb->q);
1394 if (dev->queue_mode == NULL_Q_MQ &&
1395 nullb->tag_set == &nullb->__tag_set)
1396 blk_mq_free_tag_set(nullb->tag_set);
1397 put_disk(nullb->disk);
1398 cleanup_queues(nullb);
1399 if (null_cache_active(nullb))
1400 null_free_device_storage(nullb->dev, true);
1401 kfree(nullb);
1402 dev->nullb = NULL;
1403}
1404
1405static void null_config_discard(struct nullb *nullb)
1406{
1407 if (nullb->dev->discard == false)
1408 return;
1409 nullb->q->limits.discard_granularity = nullb->dev->blocksize;
1410 nullb->q->limits.discard_alignment = nullb->dev->blocksize;
1411 blk_queue_max_discard_sectors(nullb->q, UINT_MAX >> 9);
1412 blk_queue_flag_set(QUEUE_FLAG_DISCARD, nullb->q);
1413}
1414
1415static int null_open(struct block_device *bdev, fmode_t mode)
1416{
1417 return 0;
1418}
1419
1420static void null_release(struct gendisk *disk, fmode_t mode)
1421{
1422}
1423
1424static const struct block_device_operations null_fops = {
1425 .owner = THIS_MODULE,
1426 .open = null_open,
1427 .release = null_release,
1428 .report_zones = null_zone_report,
1429};
1430
1431static void null_init_queue(struct nullb *nullb, struct nullb_queue *nq)
1432{
1433 BUG_ON(!nullb);
1434 BUG_ON(!nq);
1435
1436 init_waitqueue_head(&nq->wait);
1437 nq->queue_depth = nullb->queue_depth;
1438 nq->dev = nullb->dev;
1439}
1440
1441static void null_init_queues(struct nullb *nullb)
1442{
1443 struct request_queue *q = nullb->q;
1444 struct blk_mq_hw_ctx *hctx;
1445 struct nullb_queue *nq;
1446 int i;
1447
1448 queue_for_each_hw_ctx(q, hctx, i) {
1449 if (!hctx->nr_ctx || !hctx->tags)
1450 continue;
1451 nq = &nullb->queues[i];
1452 hctx->driver_data = nq;
1453 null_init_queue(nullb, nq);
1454 nullb->nr_queues++;
1455 }
1456}
1457
1458static int setup_commands(struct nullb_queue *nq)
1459{
1460 struct nullb_cmd *cmd;
1461 int i, tag_size;
1462
1463 nq->cmds = kcalloc(nq->queue_depth, sizeof(*cmd), GFP_KERNEL);
1464 if (!nq->cmds)
1465 return -ENOMEM;
1466
1467 tag_size = ALIGN(nq->queue_depth, BITS_PER_LONG) / BITS_PER_LONG;
1468 nq->tag_map = kcalloc(tag_size, sizeof(unsigned long), GFP_KERNEL);
1469 if (!nq->tag_map) {
1470 kfree(nq->cmds);
1471 return -ENOMEM;
1472 }
1473
1474 for (i = 0; i < nq->queue_depth; i++) {
1475 cmd = &nq->cmds[i];
1476 INIT_LIST_HEAD(&cmd->list);
1477 cmd->ll_list.next = NULL;
1478 cmd->tag = -1U;
1479 }
1480
1481 return 0;
1482}
1483
1484static int setup_queues(struct nullb *nullb)
1485{
1486 nullb->queues = kcalloc(nullb->dev->submit_queues,
1487 sizeof(struct nullb_queue),
1488 GFP_KERNEL);
1489 if (!nullb->queues)
1490 return -ENOMEM;
1491
1492 nullb->queue_depth = nullb->dev->hw_queue_depth;
1493
1494 return 0;
1495}
1496
1497static int init_driver_queues(struct nullb *nullb)
1498{
1499 struct nullb_queue *nq;
1500 int i, ret = 0;
1501
1502 for (i = 0; i < nullb->dev->submit_queues; i++) {
1503 nq = &nullb->queues[i];
1504
1505 null_init_queue(nullb, nq);
1506
1507 ret = setup_commands(nq);
1508 if (ret)
1509 return ret;
1510 nullb->nr_queues++;
1511 }
1512 return 0;
1513}
1514
1515static int null_gendisk_register(struct nullb *nullb)
1516{
1517 struct gendisk *disk;
1518 sector_t size;
1519
1520 disk = nullb->disk = alloc_disk_node(1, nullb->dev->home_node);
1521 if (!disk)
1522 return -ENOMEM;
1523 size = (sector_t)nullb->dev->size * 1024 * 1024ULL;
1524 set_capacity(disk, size >> 9);
1525
1526 disk->flags |= GENHD_FL_EXT_DEVT | GENHD_FL_SUPPRESS_PARTITION_INFO;
1527 disk->major = null_major;
1528 disk->first_minor = nullb->index;
1529 disk->fops = &null_fops;
1530 disk->private_data = nullb;
1531 disk->queue = nullb->q;
1532 strncpy(disk->disk_name, nullb->disk_name, DISK_NAME_LEN);
1533
1534 if (nullb->dev->zoned) {
1535 int ret = blk_revalidate_disk_zones(disk);
1536
1537 if (ret != 0)
1538 return ret;
1539 }
1540
1541 add_disk(disk);
1542 return 0;
1543}
1544
1545static int null_init_tag_set(struct nullb *nullb, struct blk_mq_tag_set *set)
1546{
1547 set->ops = &null_mq_ops;
1548 set->nr_hw_queues = nullb ? nullb->dev->submit_queues :
1549 g_submit_queues;
1550 set->queue_depth = nullb ? nullb->dev->hw_queue_depth :
1551 g_hw_queue_depth;
1552 set->numa_node = nullb ? nullb->dev->home_node : g_home_node;
1553 set->cmd_size = sizeof(struct nullb_cmd);
1554 set->flags = BLK_MQ_F_SHOULD_MERGE;
1555 if (g_no_sched)
1556 set->flags |= BLK_MQ_F_NO_SCHED;
1557 set->driver_data = NULL;
1558
1559 if ((nullb && nullb->dev->blocking) || g_blocking)
1560 set->flags |= BLK_MQ_F_BLOCKING;
1561
1562 return blk_mq_alloc_tag_set(set);
1563}
1564
1565static void null_validate_conf(struct nullb_device *dev)
1566{
1567 dev->blocksize = round_down(dev->blocksize, 512);
1568 dev->blocksize = clamp_t(unsigned int, dev->blocksize, 512, 4096);
1569
1570 if (dev->queue_mode == NULL_Q_MQ && dev->use_per_node_hctx) {
1571 if (dev->submit_queues != nr_online_nodes)
1572 dev->submit_queues = nr_online_nodes;
1573 } else if (dev->submit_queues > nr_cpu_ids)
1574 dev->submit_queues = nr_cpu_ids;
1575 else if (dev->submit_queues == 0)
1576 dev->submit_queues = 1;
1577
1578 dev->queue_mode = min_t(unsigned int, dev->queue_mode, NULL_Q_MQ);
1579 dev->irqmode = min_t(unsigned int, dev->irqmode, NULL_IRQ_TIMER);
1580
1581
1582 if (dev->memory_backed)
1583 dev->blocking = true;
1584 else
1585 dev->cache_size = 0;
1586 dev->cache_size = min_t(unsigned long, ULONG_MAX / 1024 / 1024,
1587 dev->cache_size);
1588 dev->mbps = min_t(unsigned int, 1024 * 40, dev->mbps);
1589
1590 if (dev->queue_mode == NULL_Q_BIO)
1591 dev->mbps = 0;
1592}
1593
1594#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
1595static bool __null_setup_fault(struct fault_attr *attr, char *str)
1596{
1597 if (!str[0])
1598 return true;
1599
1600 if (!setup_fault_attr(attr, str))
1601 return false;
1602
1603 attr->verbose = 0;
1604 return true;
1605}
1606#endif
1607
1608static bool null_setup_fault(void)
1609{
1610#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
1611 if (!__null_setup_fault(&null_timeout_attr, g_timeout_str))
1612 return false;
1613 if (!__null_setup_fault(&null_requeue_attr, g_requeue_str))
1614 return false;
1615#endif
1616 return true;
1617}
1618
1619static int null_add_dev(struct nullb_device *dev)
1620{
1621 struct nullb *nullb;
1622 int rv;
1623
1624 null_validate_conf(dev);
1625
1626 nullb = kzalloc_node(sizeof(*nullb), GFP_KERNEL, dev->home_node);
1627 if (!nullb) {
1628 rv = -ENOMEM;
1629 goto out;
1630 }
1631 nullb->dev = dev;
1632 dev->nullb = nullb;
1633
1634 spin_lock_init(&nullb->lock);
1635
1636 rv = setup_queues(nullb);
1637 if (rv)
1638 goto out_free_nullb;
1639
1640 if (dev->queue_mode == NULL_Q_MQ) {
1641 if (shared_tags) {
1642 nullb->tag_set = &tag_set;
1643 rv = 0;
1644 } else {
1645 nullb->tag_set = &nullb->__tag_set;
1646 rv = null_init_tag_set(nullb, nullb->tag_set);
1647 }
1648
1649 if (rv)
1650 goto out_cleanup_queues;
1651
1652 if (!null_setup_fault())
1653 goto out_cleanup_queues;
1654
1655 nullb->tag_set->timeout = 5 * HZ;
1656 nullb->q = blk_mq_init_queue(nullb->tag_set);
1657 if (IS_ERR(nullb->q)) {
1658 rv = -ENOMEM;
1659 goto out_cleanup_tags;
1660 }
1661 null_init_queues(nullb);
1662 } else if (dev->queue_mode == NULL_Q_BIO) {
1663 nullb->q = blk_alloc_queue_node(GFP_KERNEL, dev->home_node);
1664 if (!nullb->q) {
1665 rv = -ENOMEM;
1666 goto out_cleanup_queues;
1667 }
1668 blk_queue_make_request(nullb->q, null_queue_bio);
1669 rv = init_driver_queues(nullb);
1670 if (rv)
1671 goto out_cleanup_blk_queue;
1672 }
1673
1674 if (dev->mbps) {
1675 set_bit(NULLB_DEV_FL_THROTTLED, &dev->flags);
1676 nullb_setup_bwtimer(nullb);
1677 }
1678
1679 if (dev->cache_size > 0) {
1680 set_bit(NULLB_DEV_FL_CACHE, &nullb->dev->flags);
1681 blk_queue_write_cache(nullb->q, true, true);
1682 }
1683
1684 if (dev->zoned) {
1685 rv = null_zone_init(dev);
1686 if (rv)
1687 goto out_cleanup_blk_queue;
1688
1689 blk_queue_chunk_sectors(nullb->q, dev->zone_size_sects);
1690 nullb->q->limits.zoned = BLK_ZONED_HM;
1691 }
1692
1693 nullb->q->queuedata = nullb;
1694 blk_queue_flag_set(QUEUE_FLAG_NONROT, nullb->q);
1695 blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, nullb->q);
1696
1697 mutex_lock(&lock);
1698 nullb->index = ida_simple_get(&nullb_indexes, 0, 0, GFP_KERNEL);
1699 dev->index = nullb->index;
1700 mutex_unlock(&lock);
1701
1702 blk_queue_logical_block_size(nullb->q, dev->blocksize);
1703 blk_queue_physical_block_size(nullb->q, dev->blocksize);
1704
1705 null_config_discard(nullb);
1706
1707 sprintf(nullb->disk_name, "nullb%d", nullb->index);
1708
1709 rv = null_gendisk_register(nullb);
1710 if (rv)
1711 goto out_cleanup_zone;
1712
1713 mutex_lock(&lock);
1714 list_add_tail(&nullb->list, &nullb_list);
1715 mutex_unlock(&lock);
1716
1717 return 0;
1718out_cleanup_zone:
1719 if (dev->zoned)
1720 null_zone_exit(dev);
1721out_cleanup_blk_queue:
1722 blk_cleanup_queue(nullb->q);
1723out_cleanup_tags:
1724 if (dev->queue_mode == NULL_Q_MQ && nullb->tag_set == &nullb->__tag_set)
1725 blk_mq_free_tag_set(nullb->tag_set);
1726out_cleanup_queues:
1727 cleanup_queues(nullb);
1728out_free_nullb:
1729 kfree(nullb);
1730out:
1731 return rv;
1732}
1733
1734static int __init null_init(void)
1735{
1736 int ret = 0;
1737 unsigned int i;
1738 struct nullb *nullb;
1739 struct nullb_device *dev;
1740
1741 if (g_bs > PAGE_SIZE) {
1742 pr_warn("null_blk: invalid block size\n");
1743 pr_warn("null_blk: defaults block size to %lu\n", PAGE_SIZE);
1744 g_bs = PAGE_SIZE;
1745 }
1746
1747 if (!is_power_of_2(g_zone_size)) {
1748 pr_err("null_blk: zone_size must be power-of-two\n");
1749 return -EINVAL;
1750 }
1751
1752 if (g_home_node != NUMA_NO_NODE && g_home_node >= nr_online_nodes) {
1753 pr_err("null_blk: invalid home_node value\n");
1754 g_home_node = NUMA_NO_NODE;
1755 }
1756
1757 if (g_queue_mode == NULL_Q_RQ) {
1758 pr_err("null_blk: legacy IO path no longer available\n");
1759 return -EINVAL;
1760 }
1761 if (g_queue_mode == NULL_Q_MQ && g_use_per_node_hctx) {
1762 if (g_submit_queues != nr_online_nodes) {
1763 pr_warn("null_blk: submit_queues param is set to %u.\n",
1764 nr_online_nodes);
1765 g_submit_queues = nr_online_nodes;
1766 }
1767 } else if (g_submit_queues > nr_cpu_ids)
1768 g_submit_queues = nr_cpu_ids;
1769 else if (g_submit_queues <= 0)
1770 g_submit_queues = 1;
1771
1772 if (g_queue_mode == NULL_Q_MQ && shared_tags) {
1773 ret = null_init_tag_set(NULL, &tag_set);
1774 if (ret)
1775 return ret;
1776 }
1777
1778 config_group_init(&nullb_subsys.su_group);
1779 mutex_init(&nullb_subsys.su_mutex);
1780
1781 ret = configfs_register_subsystem(&nullb_subsys);
1782 if (ret)
1783 goto err_tagset;
1784
1785 mutex_init(&lock);
1786
1787 null_major = register_blkdev(0, "nullb");
1788 if (null_major < 0) {
1789 ret = null_major;
1790 goto err_conf;
1791 }
1792
1793 for (i = 0; i < nr_devices; i++) {
1794 dev = null_alloc_dev();
1795 if (!dev) {
1796 ret = -ENOMEM;
1797 goto err_dev;
1798 }
1799 ret = null_add_dev(dev);
1800 if (ret) {
1801 null_free_dev(dev);
1802 goto err_dev;
1803 }
1804 }
1805
1806 pr_info("null: module loaded\n");
1807 return 0;
1808
1809err_dev:
1810 while (!list_empty(&nullb_list)) {
1811 nullb = list_entry(nullb_list.next, struct nullb, list);
1812 dev = nullb->dev;
1813 null_del_dev(nullb);
1814 null_free_dev(dev);
1815 }
1816 unregister_blkdev(null_major, "nullb");
1817err_conf:
1818 configfs_unregister_subsystem(&nullb_subsys);
1819err_tagset:
1820 if (g_queue_mode == NULL_Q_MQ && shared_tags)
1821 blk_mq_free_tag_set(&tag_set);
1822 return ret;
1823}
1824
1825static void __exit null_exit(void)
1826{
1827 struct nullb *nullb;
1828
1829 configfs_unregister_subsystem(&nullb_subsys);
1830
1831 unregister_blkdev(null_major, "nullb");
1832
1833 mutex_lock(&lock);
1834 while (!list_empty(&nullb_list)) {
1835 struct nullb_device *dev;
1836
1837 nullb = list_entry(nullb_list.next, struct nullb, list);
1838 dev = nullb->dev;
1839 null_del_dev(nullb);
1840 null_free_dev(dev);
1841 }
1842 mutex_unlock(&lock);
1843
1844 if (g_queue_mode == NULL_Q_MQ && shared_tags)
1845 blk_mq_free_tag_set(&tag_set);
1846}
1847
1848module_init(null_init);
1849module_exit(null_exit);
1850
1851MODULE_AUTHOR("Jens Axboe <axboe@kernel.dk>");
1852MODULE_LICENSE("GPL");
1853
