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