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Linux 4.19.133
[linux/fpc-iii.git] / drivers / block / null_blk_main.c
blobd2d7dc9cd58d21fcfb897af6f97a50843fcffc63
1 /*
2 * Add configfs and memory store: Kyungchan Koh <kkc6196@fb.com> and
3 * Shaohua Li <shli@fb.com>
4 */
5 #include <linux/module.h>
6
7 #include <linux/moduleparam.h>
8 #include <linux/sched.h>
9 #include <linux/fs.h>
10 #include <linux/init.h>
11 #include "null_blk.h"
12
13 #define PAGE_SECTORS_SHIFT (PAGE_SHIFT - SECTOR_SHIFT)
14 #define PAGE_SECTORS (1 << PAGE_SECTORS_SHIFT)
15 #define SECTOR_MASK (PAGE_SECTORS - 1)
16
17 #define FREE_BATCH 16
18
19 #define TICKS_PER_SEC 50ULL
20 #define TIMER_INTERVAL (NSEC_PER_SEC / TICKS_PER_SEC)
21
22 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
23 static DECLARE_FAULT_ATTR(null_timeout_attr);
24 static DECLARE_FAULT_ATTR(null_requeue_attr);
25 #endif
26
27 static inline u64 mb_per_tick(int mbps)
28 {
29 return (1 << 20) / TICKS_PER_SEC * ((u64) mbps);
30 }
31
32 /*
33 * Status flags for nullb_device.
34 *
35 * CONFIGURED: Device has been configured and turned on. Cannot reconfigure.
36 * UP: Device is currently on and visible in userspace.
37 * THROTTLED: Device is being throttled.
38 * CACHE: Device is using a write-back cache.
39 */
40 enum nullb_device_flags {
41 NULLB_DEV_FL_CONFIGURED = 0,
42 NULLB_DEV_FL_UP = 1,
43 NULLB_DEV_FL_THROTTLED = 2,
44 NULLB_DEV_FL_CACHE = 3,
45 };
46
47 #define MAP_SZ ((PAGE_SIZE >> SECTOR_SHIFT) + 2)
48 /*
49 * nullb_page is a page in memory for nullb devices.
50 *
51 * @page: The page holding the data.
52 * @bitmap: The bitmap represents which sector in the page has data.
53 * Each bit represents one block size. For example, sector 8
54 * will use the 7th bit
55 * The highest 2 bits of bitmap are for special purpose. LOCK means the cache
56 * page is being flushing to storage. FREE means the cache page is freed and
57 * should be skipped from flushing to storage. Please see
58 * null_make_cache_space
59 */
60 struct nullb_page {
61 struct page *page;
62 DECLARE_BITMAP(bitmap, MAP_SZ);
63 };
64 #define NULLB_PAGE_LOCK (MAP_SZ - 1)
65 #define NULLB_PAGE_FREE (MAP_SZ - 2)
66
67 static LIST_HEAD(nullb_list);
68 static struct mutex lock;
69 static int null_major;
70 static DEFINE_IDA(nullb_indexes);
71 static struct blk_mq_tag_set tag_set;
72
73 enum {
74 NULL_IRQ_NONE = 0,
75 NULL_IRQ_SOFTIRQ = 1,
76 NULL_IRQ_TIMER = 2,
77 };
78
79 enum {
80 NULL_Q_BIO = 0,
81 NULL_Q_RQ = 1,
82 NULL_Q_MQ = 2,
83 };
84
85 static int g_no_sched;
86 module_param_named(no_sched, g_no_sched, int, 0444);
87 MODULE_PARM_DESC(no_sched, "No io scheduler");
88
89 static int g_submit_queues = 1;
90 module_param_named(submit_queues, g_submit_queues, int, 0444);
91 MODULE_PARM_DESC(submit_queues, "Number of submission queues");
92
93 static int g_home_node = NUMA_NO_NODE;
94 module_param_named(home_node, g_home_node, int, 0444);
95 MODULE_PARM_DESC(home_node, "Home node for the device");
96
97 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
98 static char g_timeout_str[80];
99 module_param_string(timeout, g_timeout_str, sizeof(g_timeout_str), 0444);
100
101 static char g_requeue_str[80];
102 module_param_string(requeue, g_requeue_str, sizeof(g_requeue_str), 0444);
103 #endif
104
105 static int g_queue_mode = NULL_Q_MQ;
106
107 static int null_param_store_val(const char *str, int *val, int min, int max)
108 {
109 int ret, new_val;
110
111 ret = kstrtoint(str, 10, &new_val);
112 if (ret)
113 return -EINVAL;
114
115 if (new_val < min || new_val > max)
116 return -EINVAL;
117
118 *val = new_val;
119 return 0;
120 }
121
122 static int null_set_queue_mode(const char *str, const struct kernel_param *kp)
123 {
124 return null_param_store_val(str, &g_queue_mode, NULL_Q_BIO, NULL_Q_MQ);
125 }
126
127 static const struct kernel_param_ops null_queue_mode_param_ops = {
128 .set = null_set_queue_mode,
129 .get = param_get_int,
130 };
131
132 device_param_cb(queue_mode, &null_queue_mode_param_ops, &g_queue_mode, 0444);
133 MODULE_PARM_DESC(queue_mode, "Block interface to use (0=bio,1=rq,2=multiqueue)");
134
135 static int g_gb = 250;
136 module_param_named(gb, g_gb, int, 0444);
137 MODULE_PARM_DESC(gb, "Size in GB");
138
139 static int g_bs = 512;
140 module_param_named(bs, g_bs, int, 0444);
141 MODULE_PARM_DESC(bs, "Block size (in bytes)");
142
143 static int nr_devices = 1;
144 module_param(nr_devices, int, 0444);
145 MODULE_PARM_DESC(nr_devices, "Number of devices to register");
146
147 static bool g_blocking;
148 module_param_named(blocking, g_blocking, bool, 0444);
149 MODULE_PARM_DESC(blocking, "Register as a blocking blk-mq driver device");
150
151 static bool shared_tags;
152 module_param(shared_tags, bool, 0444);
153 MODULE_PARM_DESC(shared_tags, "Share tag set between devices for blk-mq");
154
155 static int g_irqmode = NULL_IRQ_SOFTIRQ;
156
157 static int null_set_irqmode(const char *str, const struct kernel_param *kp)
158 {
159 return null_param_store_val(str, &g_irqmode, NULL_IRQ_NONE,
160 NULL_IRQ_TIMER);
161 }
162
163 static const struct kernel_param_ops null_irqmode_param_ops = {
164 .set = null_set_irqmode,
165 .get = param_get_int,
166 };
167
168 device_param_cb(irqmode, &null_irqmode_param_ops, &g_irqmode, 0444);
169 MODULE_PARM_DESC(irqmode, "IRQ completion handler. 0-none, 1-softirq, 2-timer");
170
171 static unsigned long g_completion_nsec = 10000;
172 module_param_named(completion_nsec, g_completion_nsec, ulong, 0444);
173 MODULE_PARM_DESC(completion_nsec, "Time in ns to complete a request in hardware. Default: 10,000ns");
174
175 static int g_hw_queue_depth = 64;
176 module_param_named(hw_queue_depth, g_hw_queue_depth, int, 0444);
177 MODULE_PARM_DESC(hw_queue_depth, "Queue depth for each hardware queue. Default: 64");
178
179 static bool g_use_per_node_hctx;
180 module_param_named(use_per_node_hctx, g_use_per_node_hctx, bool, 0444);
181 MODULE_PARM_DESC(use_per_node_hctx, "Use per-node allocation for hardware context queues. Default: false");
182
183 static bool g_zoned;
184 module_param_named(zoned, g_zoned, bool, S_IRUGO);
185 MODULE_PARM_DESC(zoned, "Make device as a host-managed zoned block device. Default: false");
186
187 static unsigned long g_zone_size = 256;
188 module_param_named(zone_size, g_zone_size, ulong, S_IRUGO);
189 MODULE_PARM_DESC(zone_size, "Zone size in MB when block device is zoned. Must be power-of-two: Default: 256");
190
191 static struct nullb_device *null_alloc_dev(void);
192 static void null_free_dev(struct nullb_device *dev);
193 static void null_del_dev(struct nullb *nullb);
194 static int null_add_dev(struct nullb_device *dev);
195 static void null_free_device_storage(struct nullb_device *dev, bool is_cache);
196
197 static inline struct nullb_device *to_nullb_device(struct config_item *item)
198 {
199 return item ? container_of(item, struct nullb_device, item) : NULL;
200 }
201
202 static inline ssize_t nullb_device_uint_attr_show(unsigned int val, char *page)
203 {
204 return snprintf(page, PAGE_SIZE, "%u\n", val);
205 }
206
207 static inline ssize_t nullb_device_ulong_attr_show(unsigned long val,
208 char *page)
209 {
210 return snprintf(page, PAGE_SIZE, "%lu\n", val);
211 }
212
213 static inline ssize_t nullb_device_bool_attr_show(bool val, char *page)
214 {
215 return snprintf(page, PAGE_SIZE, "%u\n", val);
216 }
217
218 static ssize_t nullb_device_uint_attr_store(unsigned int *val,
219 const char *page, size_t count)
220 {
221 unsigned int tmp;
222 int result;
223
224 result = kstrtouint(page, 0, &tmp);
225 if (result)
226 return result;
227
228 *val = tmp;
229 return count;
230 }
231
232 static ssize_t nullb_device_ulong_attr_store(unsigned long *val,
233 const char *page, size_t count)
234 {
235 int result;
236 unsigned long tmp;
237
238 result = kstrtoul(page, 0, &tmp);
239 if (result)
240 return result;
241
242 *val = tmp;
243 return count;
244 }
245
246 static ssize_t nullb_device_bool_attr_store(bool *val, const char *page,
247 size_t count)
248 {
249 bool tmp;
250 int result;
251
252 result = kstrtobool(page, &tmp);
253 if (result)
254 return result;
255
256 *val = tmp;
257 return count;
258 }
259
260 /* The following macro should only be used with TYPE = {uint, ulong, bool}. */
261 #define NULLB_DEVICE_ATTR(NAME, TYPE) \
262 static ssize_t \
263 nullb_device_##NAME##_show(struct config_item *item, char *page) \
264 { \
265 return nullb_device_##TYPE##_attr_show( \
266 to_nullb_device(item)->NAME, page); \
267 } \
268 static ssize_t \
269 nullb_device_##NAME##_store(struct config_item *item, const char *page, \
270 size_t count) \
271 { \
272 if (test_bit(NULLB_DEV_FL_CONFIGURED, &to_nullb_device(item)->flags)) \
273 return -EBUSY; \
274 return nullb_device_##TYPE##_attr_store( \
275 &to_nullb_device(item)->NAME, page, count); \
276 } \
277 CONFIGFS_ATTR(nullb_device_, NAME);
278
279 NULLB_DEVICE_ATTR(size, ulong);
280 NULLB_DEVICE_ATTR(completion_nsec, ulong);
281 NULLB_DEVICE_ATTR(submit_queues, uint);
282 NULLB_DEVICE_ATTR(home_node, uint);
283 NULLB_DEVICE_ATTR(queue_mode, uint);
284 NULLB_DEVICE_ATTR(blocksize, uint);
285 NULLB_DEVICE_ATTR(irqmode, uint);
286 NULLB_DEVICE_ATTR(hw_queue_depth, uint);
287 NULLB_DEVICE_ATTR(index, uint);
288 NULLB_DEVICE_ATTR(blocking, bool);
289 NULLB_DEVICE_ATTR(use_per_node_hctx, bool);
290 NULLB_DEVICE_ATTR(memory_backed, bool);
291 NULLB_DEVICE_ATTR(discard, bool);
292 NULLB_DEVICE_ATTR(mbps, uint);
293 NULLB_DEVICE_ATTR(cache_size, ulong);
294 NULLB_DEVICE_ATTR(zoned, bool);
295 NULLB_DEVICE_ATTR(zone_size, ulong);
296
297 static ssize_t nullb_device_power_show(struct config_item *item, char *page)
298 {
299 return nullb_device_bool_attr_show(to_nullb_device(item)->power, page);
300 }
301
302 static ssize_t nullb_device_power_store(struct config_item *item,
303 const char *page, size_t count)
304 {
305 struct nullb_device *dev = to_nullb_device(item);
306 bool newp = false;
307 ssize_t ret;
308
309 ret = nullb_device_bool_attr_store(&newp, page, count);
310 if (ret < 0)
311 return ret;
312
313 if (!dev->power && newp) {
314 if (test_and_set_bit(NULLB_DEV_FL_UP, &dev->flags))
315 return count;
316 if (null_add_dev(dev)) {
317 clear_bit(NULLB_DEV_FL_UP, &dev->flags);
318 return -ENOMEM;
319 }
320
321 set_bit(NULLB_DEV_FL_CONFIGURED, &dev->flags);
322 dev->power = newp;
323 } else if (dev->power && !newp) {
324 if (test_and_clear_bit(NULLB_DEV_FL_UP, &dev->flags)) {
325 mutex_lock(&lock);
326 dev->power = newp;
327 null_del_dev(dev->nullb);
328 mutex_unlock(&lock);
329 }
330 clear_bit(NULLB_DEV_FL_CONFIGURED, &dev->flags);
331 }
332
333 return count;
334 }
335
336 CONFIGFS_ATTR(nullb_device_, power);
337
338 static ssize_t nullb_device_badblocks_show(struct config_item *item, char *page)
339 {
340 struct nullb_device *t_dev = to_nullb_device(item);
341
342 return badblocks_show(&t_dev->badblocks, page, 0);
343 }
344
345 static ssize_t nullb_device_badblocks_store(struct config_item *item,
346 const char *page, size_t count)
347 {
348 struct nullb_device *t_dev = to_nullb_device(item);
349 char *orig, *buf, *tmp;
350 u64 start, end;
351 int ret;
352
353 orig = kstrndup(page, count, GFP_KERNEL);
354 if (!orig)
355 return -ENOMEM;
356
357 buf = strstrip(orig);
358
359 ret = -EINVAL;
360 if (buf[0] != '+' && buf[0] != '-')
361 goto out;
362 tmp = strchr(&buf[1], '-');
363 if (!tmp)
364 goto out;
365 *tmp = '\0';
366 ret = kstrtoull(buf + 1, 0, &start);
367 if (ret)
368 goto out;
369 ret = kstrtoull(tmp + 1, 0, &end);
370 if (ret)
371 goto out;
372 ret = -EINVAL;
373 if (start > end)
374 goto out;
375 /* enable badblocks */
376 cmpxchg(&t_dev->badblocks.shift, -1, 0);
377 if (buf[0] == '+')
378 ret = badblocks_set(&t_dev->badblocks, start,
379 end - start + 1, 1);
380 else
381 ret = badblocks_clear(&t_dev->badblocks, start,
382 end - start + 1);
383 if (ret == 0)
384 ret = count;
385 out:
386 kfree(orig);
387 return ret;
388 }
389 CONFIGFS_ATTR(nullb_device_, badblocks);
390
391 static struct configfs_attribute *nullb_device_attrs[] = {
392 &nullb_device_attr_size,
393 &nullb_device_attr_completion_nsec,
394 &nullb_device_attr_submit_queues,
395 &nullb_device_attr_home_node,
396 &nullb_device_attr_queue_mode,
397 &nullb_device_attr_blocksize,
398 &nullb_device_attr_irqmode,
399 &nullb_device_attr_hw_queue_depth,
400 &nullb_device_attr_index,
401 &nullb_device_attr_blocking,
402 &nullb_device_attr_use_per_node_hctx,
403 &nullb_device_attr_power,
404 &nullb_device_attr_memory_backed,
405 &nullb_device_attr_discard,
406 &nullb_device_attr_mbps,
407 &nullb_device_attr_cache_size,
408 &nullb_device_attr_badblocks,
409 &nullb_device_attr_zoned,
410 &nullb_device_attr_zone_size,
411 NULL,
412 };
413
414 static void nullb_device_release(struct config_item *item)
415 {
416 struct nullb_device *dev = to_nullb_device(item);
417
418 null_free_device_storage(dev, false);
419 null_free_dev(dev);
420 }
421
422 static struct configfs_item_operations nullb_device_ops = {
423 .release = nullb_device_release,
424 };
425
426 static const struct config_item_type nullb_device_type = {
427 .ct_item_ops = &nullb_device_ops,
428 .ct_attrs = nullb_device_attrs,
429 .ct_owner = THIS_MODULE,
430 };
431
432 static struct
433 config_item *nullb_group_make_item(struct config_group *group, const char *name)
434 {
435 struct nullb_device *dev;
436
437 dev = null_alloc_dev();
438 if (!dev)
439 return ERR_PTR(-ENOMEM);
440
441 config_item_init_type_name(&dev->item, name, &nullb_device_type);
442
443 return &dev->item;
444 }
445
446 static void
447 nullb_group_drop_item(struct config_group *group, struct config_item *item)
448 {
449 struct nullb_device *dev = to_nullb_device(item);
450
451 if (test_and_clear_bit(NULLB_DEV_FL_UP, &dev->flags)) {
452 mutex_lock(&lock);
453 dev->power = false;
454 null_del_dev(dev->nullb);
455 mutex_unlock(&lock);
456 }
457
458 config_item_put(item);
459 }
460
461 static ssize_t memb_group_features_show(struct config_item *item, char *page)
462 {
463 return snprintf(page, PAGE_SIZE, "memory_backed,discard,bandwidth,cache,badblocks,zoned,zone_size\n");
464 }
465
466 CONFIGFS_ATTR_RO(memb_group_, features);
467
468 static struct configfs_attribute *nullb_group_attrs[] = {
469 &memb_group_attr_features,
470 NULL,
471 };
472
473 static struct configfs_group_operations nullb_group_ops = {
474 .make_item = nullb_group_make_item,
475 .drop_item = nullb_group_drop_item,
476 };
477
478 static const struct config_item_type nullb_group_type = {
479 .ct_group_ops = &nullb_group_ops,
480 .ct_attrs = nullb_group_attrs,
481 .ct_owner = THIS_MODULE,
482 };
483
484 static struct configfs_subsystem nullb_subsys = {
485 .su_group = {
486 .cg_item = {
487 .ci_namebuf = "nullb",
488 .ci_type = &nullb_group_type,
489 },
490 },
491 };
492
493 static inline int null_cache_active(struct nullb *nullb)
494 {
495 return test_bit(NULLB_DEV_FL_CACHE, &nullb->dev->flags);
496 }
497
498 static struct nullb_device *null_alloc_dev(void)
499 {
500 struct nullb_device *dev;
501
502 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
503 if (!dev)
504 return NULL;
505 INIT_RADIX_TREE(&dev->data, GFP_ATOMIC);
506 INIT_RADIX_TREE(&dev->cache, GFP_ATOMIC);
507 if (badblocks_init(&dev->badblocks, 0)) {
508 kfree(dev);
509 return NULL;
510 }
511
512 dev->size = g_gb * 1024;
513 dev->completion_nsec = g_completion_nsec;
514 dev->submit_queues = g_submit_queues;
515 dev->home_node = g_home_node;
516 dev->queue_mode = g_queue_mode;
517 dev->blocksize = g_bs;
518 dev->irqmode = g_irqmode;
519 dev->hw_queue_depth = g_hw_queue_depth;
520 dev->blocking = g_blocking;
521 dev->use_per_node_hctx = g_use_per_node_hctx;
522 dev->zoned = g_zoned;
523 dev->zone_size = g_zone_size;
524 return dev;
525 }
526
527 static void null_free_dev(struct nullb_device *dev)
528 {
529 if (!dev)
530 return;
531
532 null_zone_exit(dev);
533 badblocks_exit(&dev->badblocks);
534 kfree(dev);
535 }
536
537 static void put_tag(struct nullb_queue *nq, unsigned int tag)
538 {
539 clear_bit_unlock(tag, nq->tag_map);
540
541 if (waitqueue_active(&nq->wait))
542 wake_up(&nq->wait);
543 }
544
545 static unsigned int get_tag(struct nullb_queue *nq)
546 {
547 unsigned int tag;
548
549 do {
550 tag = find_first_zero_bit(nq->tag_map, nq->queue_depth);
551 if (tag >= nq->queue_depth)
552 return -1U;
553 } while (test_and_set_bit_lock(tag, nq->tag_map));
554
555 return tag;
556 }
557
558 static void free_cmd(struct nullb_cmd *cmd)
559 {
560 put_tag(cmd->nq, cmd->tag);
561 }
562
563 static enum hrtimer_restart null_cmd_timer_expired(struct hrtimer *timer);
564
565 static struct nullb_cmd *__alloc_cmd(struct nullb_queue *nq)
566 {
567 struct nullb_cmd *cmd;
568 unsigned int tag;
569
570 tag = get_tag(nq);
571 if (tag != -1U) {
572 cmd = &nq->cmds[tag];
573 cmd->tag = tag;
574 cmd->error = BLK_STS_OK;
575 cmd->nq = nq;
576 if (nq->dev->irqmode == NULL_IRQ_TIMER) {
577 hrtimer_init(&cmd->timer, CLOCK_MONOTONIC,
578 HRTIMER_MODE_REL);
579 cmd->timer.function = null_cmd_timer_expired;
580 }
581 return cmd;
582 }
583
584 return NULL;
585 }
586
587 static struct nullb_cmd *alloc_cmd(struct nullb_queue *nq, int can_wait)
588 {
589 struct nullb_cmd *cmd;
590 DEFINE_WAIT(wait);
591
592 cmd = __alloc_cmd(nq);
593 if (cmd || !can_wait)
594 return cmd;
595
596 do {
597 prepare_to_wait(&nq->wait, &wait, TASK_UNINTERRUPTIBLE);
598 cmd = __alloc_cmd(nq);
599 if (cmd)
600 break;
601
602 io_schedule();
603 } while (1);
604
605 finish_wait(&nq->wait, &wait);
606 return cmd;
607 }
608
609 static void end_cmd(struct nullb_cmd *cmd)
610 {
611 struct request_queue *q = NULL;
612 int queue_mode = cmd->nq->dev->queue_mode;
613
614 if (cmd->rq)
615 q = cmd->rq->q;
616
617 switch (queue_mode) {
618 case NULL_Q_MQ:
619 blk_mq_end_request(cmd->rq, cmd->error);
620 return;
621 case NULL_Q_RQ:
622 INIT_LIST_HEAD(&cmd->rq->queuelist);
623 blk_end_request_all(cmd->rq, cmd->error);
624 break;
625 case NULL_Q_BIO:
626 cmd->bio->bi_status = cmd->error;
627 bio_endio(cmd->bio);
628 break;
629 }
630
631 free_cmd(cmd);
632
633 /* Restart queue if needed, as we are freeing a tag */
634 if (queue_mode == NULL_Q_RQ && blk_queue_stopped(q)) {
635 unsigned long flags;
636
637 spin_lock_irqsave(q->queue_lock, flags);
638 blk_start_queue_async(q);
639 spin_unlock_irqrestore(q->queue_lock, flags);
640 }
641 }
642
643 static enum hrtimer_restart null_cmd_timer_expired(struct hrtimer *timer)
644 {
645 end_cmd(container_of(timer, struct nullb_cmd, timer));
646
647 return HRTIMER_NORESTART;
648 }
649
650 static void null_cmd_end_timer(struct nullb_cmd *cmd)
651 {
652 ktime_t kt = cmd->nq->dev->completion_nsec;
653
654 hrtimer_start(&cmd->timer, kt, HRTIMER_MODE_REL);
655 }
656
657 static void null_softirq_done_fn(struct request *rq)
658 {
659 struct nullb *nullb = rq->q->queuedata;
660
661 if (nullb->dev->queue_mode == NULL_Q_MQ)
662 end_cmd(blk_mq_rq_to_pdu(rq));
663 else
664 end_cmd(rq->special);
665 }
666
667 static struct nullb_page *null_alloc_page(gfp_t gfp_flags)
668 {
669 struct nullb_page *t_page;
670
671 t_page = kmalloc(sizeof(struct nullb_page), gfp_flags);
672 if (!t_page)
673 goto out;
674
675 t_page->page = alloc_pages(gfp_flags, 0);
676 if (!t_page->page)
677 goto out_freepage;
678
679 memset(t_page->bitmap, 0, sizeof(t_page->bitmap));
680 return t_page;
681 out_freepage:
682 kfree(t_page);
683 out:
684 return NULL;
685 }
686
687 static void null_free_page(struct nullb_page *t_page)
688 {
689 __set_bit(NULLB_PAGE_FREE, t_page->bitmap);
690 if (test_bit(NULLB_PAGE_LOCK, t_page->bitmap))
691 return;
692 __free_page(t_page->page);
693 kfree(t_page);
694 }
695
696 static bool null_page_empty(struct nullb_page *page)
697 {
698 int size = MAP_SZ - 2;
699
700 return find_first_bit(page->bitmap, size) == size;
701 }
702
703 static void null_free_sector(struct nullb *nullb, sector_t sector,
704 bool is_cache)
705 {
706 unsigned int sector_bit;
707 u64 idx;
708 struct nullb_page *t_page, *ret;
709 struct radix_tree_root *root;
710
711 root = is_cache ? &nullb->dev->cache : &nullb->dev->data;
712 idx = sector >> PAGE_SECTORS_SHIFT;
713 sector_bit = (sector & SECTOR_MASK);
714
715 t_page = radix_tree_lookup(root, idx);
716 if (t_page) {
717 __clear_bit(sector_bit, t_page->bitmap);
718
719 if (null_page_empty(t_page)) {
720 ret = radix_tree_delete_item(root, idx, t_page);
721 WARN_ON(ret != t_page);
722 null_free_page(ret);
723 if (is_cache)
724 nullb->dev->curr_cache -= PAGE_SIZE;
725 }
726 }
727 }
728
729 static struct nullb_page *null_radix_tree_insert(struct nullb *nullb, u64 idx,
730 struct nullb_page *t_page, bool is_cache)
731 {
732 struct radix_tree_root *root;
733
734 root = is_cache ? &nullb->dev->cache : &nullb->dev->data;
735
736 if (radix_tree_insert(root, idx, t_page)) {
737 null_free_page(t_page);
738 t_page = radix_tree_lookup(root, idx);
739 WARN_ON(!t_page || t_page->page->index != idx);
740 } else if (is_cache)
741 nullb->dev->curr_cache += PAGE_SIZE;
742
743 return t_page;
744 }
745
746 static void null_free_device_storage(struct nullb_device *dev, bool is_cache)
747 {
748 unsigned long pos = 0;
749 int nr_pages;
750 struct nullb_page *ret, *t_pages[FREE_BATCH];
751 struct radix_tree_root *root;
752
753 root = is_cache ? &dev->cache : &dev->data;
754
755 do {
756 int i;
757
758 nr_pages = radix_tree_gang_lookup(root,
759 (void **)t_pages, pos, FREE_BATCH);
760
761 for (i = 0; i < nr_pages; i++) {
762 pos = t_pages[i]->page->index;
763 ret = radix_tree_delete_item(root, pos, t_pages[i]);
764 WARN_ON(ret != t_pages[i]);
765 null_free_page(ret);
766 }
767
768 pos++;
769 } while (nr_pages == FREE_BATCH);
770
771 if (is_cache)
772 dev->curr_cache = 0;
773 }
774
775 static struct nullb_page *__null_lookup_page(struct nullb *nullb,
776 sector_t sector, bool for_write, bool is_cache)
777 {
778 unsigned int sector_bit;
779 u64 idx;
780 struct nullb_page *t_page;
781 struct radix_tree_root *root;
782
783 idx = sector >> PAGE_SECTORS_SHIFT;
784 sector_bit = (sector & SECTOR_MASK);
785
786 root = is_cache ? &nullb->dev->cache : &nullb->dev->data;
787 t_page = radix_tree_lookup(root, idx);
788 WARN_ON(t_page && t_page->page->index != idx);
789
790 if (t_page && (for_write || test_bit(sector_bit, t_page->bitmap)))
791 return t_page;
792
793 return NULL;
794 }
795
796 static struct nullb_page *null_lookup_page(struct nullb *nullb,
797 sector_t sector, bool for_write, bool ignore_cache)
798 {
799 struct nullb_page *page = NULL;
800
801 if (!ignore_cache)
802 page = __null_lookup_page(nullb, sector, for_write, true);
803 if (page)
804 return page;
805 return __null_lookup_page(nullb, sector, for_write, false);
806 }
807
808 static struct nullb_page *null_insert_page(struct nullb *nullb,
809 sector_t sector, bool ignore_cache)
810 __releases(&nullb->lock)
811 __acquires(&nullb->lock)
812 {
813 u64 idx;
814 struct nullb_page *t_page;
815
816 t_page = null_lookup_page(nullb, sector, true, ignore_cache);
817 if (t_page)
818 return t_page;
819
820 spin_unlock_irq(&nullb->lock);
821
822 t_page = null_alloc_page(GFP_NOIO);
823 if (!t_page)
824 goto out_lock;
825
826 if (radix_tree_preload(GFP_NOIO))
827 goto out_freepage;
828
829 spin_lock_irq(&nullb->lock);
830 idx = sector >> PAGE_SECTORS_SHIFT;
831 t_page->page->index = idx;
832 t_page = null_radix_tree_insert(nullb, idx, t_page, !ignore_cache);
833 radix_tree_preload_end();
834
835 return t_page;
836 out_freepage:
837 null_free_page(t_page);
838 out_lock:
839 spin_lock_irq(&nullb->lock);
840 return null_lookup_page(nullb, sector, true, ignore_cache);
841 }
842
843 static int null_flush_cache_page(struct nullb *nullb, struct nullb_page *c_page)
844 {
845 int i;
846 unsigned int offset;
847 u64 idx;
848 struct nullb_page *t_page, *ret;
849 void *dst, *src;
850
851 idx = c_page->page->index;
852
853 t_page = null_insert_page(nullb, idx << PAGE_SECTORS_SHIFT, true);
854
855 __clear_bit(NULLB_PAGE_LOCK, c_page->bitmap);
856 if (test_bit(NULLB_PAGE_FREE, c_page->bitmap)) {
857 null_free_page(c_page);
858 if (t_page && null_page_empty(t_page)) {
859 ret = radix_tree_delete_item(&nullb->dev->data,
860 idx, t_page);
861 null_free_page(t_page);
862 }
863 return 0;
864 }
865
866 if (!t_page)
867 return -ENOMEM;
868
869 src = kmap_atomic(c_page->page);
870 dst = kmap_atomic(t_page->page);
871
872 for (i = 0; i < PAGE_SECTORS;
873 i += (nullb->dev->blocksize >> SECTOR_SHIFT)) {
874 if (test_bit(i, c_page->bitmap)) {
875 offset = (i << SECTOR_SHIFT);
876 memcpy(dst + offset, src + offset,
877 nullb->dev->blocksize);
878 __set_bit(i, t_page->bitmap);
879 }
880 }
881
882 kunmap_atomic(dst);
883 kunmap_atomic(src);
884
885 ret = radix_tree_delete_item(&nullb->dev->cache, idx, c_page);
886 null_free_page(ret);
887 nullb->dev->curr_cache -= PAGE_SIZE;
888
889 return 0;
890 }
891
892 static int null_make_cache_space(struct nullb *nullb, unsigned long n)
893 {
894 int i, err, nr_pages;
895 struct nullb_page *c_pages[FREE_BATCH];
896 unsigned long flushed = 0, one_round;
897
898 again:
899 if ((nullb->dev->cache_size * 1024 * 1024) >
900 nullb->dev->curr_cache + n || nullb->dev->curr_cache == 0)
901 return 0;
902
903 nr_pages = radix_tree_gang_lookup(&nullb->dev->cache,
904 (void **)c_pages, nullb->cache_flush_pos, FREE_BATCH);
905 /*
906 * nullb_flush_cache_page could unlock before using the c_pages. To
907 * avoid race, we don't allow page free
908 */
909 for (i = 0; i < nr_pages; i++) {
910 nullb->cache_flush_pos = c_pages[i]->page->index;
911 /*
912 * We found the page which is being flushed to disk by other
913 * threads
914 */
915 if (test_bit(NULLB_PAGE_LOCK, c_pages[i]->bitmap))
916 c_pages[i] = NULL;
917 else
918 __set_bit(NULLB_PAGE_LOCK, c_pages[i]->bitmap);
919 }
920
921 one_round = 0;
922 for (i = 0; i < nr_pages; i++) {
923 if (c_pages[i] == NULL)
924 continue;
925 err = null_flush_cache_page(nullb, c_pages[i]);
926 if (err)
927 return err;
928 one_round++;
929 }
930 flushed += one_round << PAGE_SHIFT;
931
932 if (n > flushed) {
933 if (nr_pages == 0)
934 nullb->cache_flush_pos = 0;
935 if (one_round == 0) {
936 /* give other threads a chance */
937 spin_unlock_irq(&nullb->lock);
938 spin_lock_irq(&nullb->lock);
939 }
940 goto again;
941 }
942 return 0;
943 }
944
945 static int copy_to_nullb(struct nullb *nullb, struct page *source,
946 unsigned int off, sector_t sector, size_t n, bool is_fua)
947 {
948 size_t temp, count = 0;
949 unsigned int offset;
950 struct nullb_page *t_page;
951 void *dst, *src;
952
953 while (count < n) {
954 temp = min_t(size_t, nullb->dev->blocksize, n - count);
955
956 if (null_cache_active(nullb) && !is_fua)
957 null_make_cache_space(nullb, PAGE_SIZE);
958
959 offset = (sector & SECTOR_MASK) << SECTOR_SHIFT;
960 t_page = null_insert_page(nullb, sector,
961 !null_cache_active(nullb) || is_fua);
962 if (!t_page)
963 return -ENOSPC;
964
965 src = kmap_atomic(source);
966 dst = kmap_atomic(t_page->page);
967 memcpy(dst + offset, src + off + count, temp);
968 kunmap_atomic(dst);
969 kunmap_atomic(src);
970
971 __set_bit(sector & SECTOR_MASK, t_page->bitmap);
972
973 if (is_fua)
974 null_free_sector(nullb, sector, true);
975
976 count += temp;
977 sector += temp >> SECTOR_SHIFT;
978 }
979 return 0;
980 }
981
982 static int copy_from_nullb(struct nullb *nullb, struct page *dest,
983 unsigned int off, sector_t sector, size_t n)
984 {
985 size_t temp, count = 0;
986 unsigned int offset;
987 struct nullb_page *t_page;
988 void *dst, *src;
989
990 while (count < n) {
991 temp = min_t(size_t, nullb->dev->blocksize, n - count);
992
993 offset = (sector & SECTOR_MASK) << SECTOR_SHIFT;
994 t_page = null_lookup_page(nullb, sector, false,
995 !null_cache_active(nullb));
996
997 dst = kmap_atomic(dest);
998 if (!t_page) {
999 memset(dst + off + count, 0, temp);
1000 goto next;
1001 }
1002 src = kmap_atomic(t_page->page);
1003 memcpy(dst + off + count, src + offset, temp);
1004 kunmap_atomic(src);
1005 next:
1006 kunmap_atomic(dst);
1007
1008 count += temp;
1009 sector += temp >> SECTOR_SHIFT;
1010 }
1011 return 0;
1012 }
1013
1014 static void null_handle_discard(struct nullb *nullb, sector_t sector, size_t n)
1015 {
1016 size_t temp;
1017
1018 spin_lock_irq(&nullb->lock);
1019 while (n > 0) {
1020 temp = min_t(size_t, n, nullb->dev->blocksize);
1021 null_free_sector(nullb, sector, false);
1022 if (null_cache_active(nullb))
1023 null_free_sector(nullb, sector, true);
1024 sector += temp >> SECTOR_SHIFT;
1025 n -= temp;
1026 }
1027 spin_unlock_irq(&nullb->lock);
1028 }
1029
1030 static int null_handle_flush(struct nullb *nullb)
1031 {
1032 int err;
1033
1034 if (!null_cache_active(nullb))
1035 return 0;
1036
1037 spin_lock_irq(&nullb->lock);
1038 while (true) {
1039 err = null_make_cache_space(nullb,
1040 nullb->dev->cache_size * 1024 * 1024);
1041 if (err || nullb->dev->curr_cache == 0)
1042 break;
1043 }
1044
1045 WARN_ON(!radix_tree_empty(&nullb->dev->cache));
1046 spin_unlock_irq(&nullb->lock);
1047 return err;
1048 }
1049
1050 static int null_transfer(struct nullb *nullb, struct page *page,
1051 unsigned int len, unsigned int off, bool is_write, sector_t sector,
1052 bool is_fua)
1053 {
1054 int err = 0;
1055
1056 if (!is_write) {
1057 err = copy_from_nullb(nullb, page, off, sector, len);
1058 flush_dcache_page(page);
1059 } else {
1060 flush_dcache_page(page);
1061 err = copy_to_nullb(nullb, page, off, sector, len, is_fua);
1062 }
1063
1064 return err;
1065 }
1066
1067 static int null_handle_rq(struct nullb_cmd *cmd)
1068 {
1069 struct request *rq = cmd->rq;
1070 struct nullb *nullb = cmd->nq->dev->nullb;
1071 int err;
1072 unsigned int len;
1073 sector_t sector;
1074 struct req_iterator iter;
1075 struct bio_vec bvec;
1076
1077 sector = blk_rq_pos(rq);
1078
1079 if (req_op(rq) == REQ_OP_DISCARD) {
1080 null_handle_discard(nullb, sector, blk_rq_bytes(rq));
1081 return 0;
1082 }
1083
1084 spin_lock_irq(&nullb->lock);
1085 rq_for_each_segment(bvec, rq, iter) {
1086 len = bvec.bv_len;
1087 err = null_transfer(nullb, bvec.bv_page, len, bvec.bv_offset,
1088 op_is_write(req_op(rq)), sector,
1089 req_op(rq) & REQ_FUA);
1090 if (err) {
1091 spin_unlock_irq(&nullb->lock);
1092 return err;
1093 }
1094 sector += len >> SECTOR_SHIFT;
1095 }
1096 spin_unlock_irq(&nullb->lock);
1097
1098 return 0;
1099 }
1100
1101 static int null_handle_bio(struct nullb_cmd *cmd)
1102 {
1103 struct bio *bio = cmd->bio;
1104 struct nullb *nullb = cmd->nq->dev->nullb;
1105 int err;
1106 unsigned int len;
1107 sector_t sector;
1108 struct bio_vec bvec;
1109 struct bvec_iter iter;
1110
1111 sector = bio->bi_iter.bi_sector;
1112
1113 if (bio_op(bio) == REQ_OP_DISCARD) {
1114 null_handle_discard(nullb, sector,
1115 bio_sectors(bio) << SECTOR_SHIFT);
1116 return 0;
1117 }
1118
1119 spin_lock_irq(&nullb->lock);
1120 bio_for_each_segment(bvec, bio, iter) {
1121 len = bvec.bv_len;
1122 err = null_transfer(nullb, bvec.bv_page, len, bvec.bv_offset,
1123 op_is_write(bio_op(bio)), sector,
1124 bio_op(bio) & REQ_FUA);
1125 if (err) {
1126 spin_unlock_irq(&nullb->lock);
1127 return err;
1128 }
1129 sector += len >> SECTOR_SHIFT;
1130 }
1131 spin_unlock_irq(&nullb->lock);
1132 return 0;
1133 }
1134
1135 static void null_stop_queue(struct nullb *nullb)
1136 {
1137 struct request_queue *q = nullb->q;
1138
1139 if (nullb->dev->queue_mode == NULL_Q_MQ)
1140 blk_mq_stop_hw_queues(q);
1141 else {
1142 spin_lock_irq(q->queue_lock);
1143 blk_stop_queue(q);
1144 spin_unlock_irq(q->queue_lock);
1145 }
1146 }
1147
1148 static void null_restart_queue_async(struct nullb *nullb)
1149 {
1150 struct request_queue *q = nullb->q;
1151 unsigned long flags;
1152
1153 if (nullb->dev->queue_mode == NULL_Q_MQ)
1154 blk_mq_start_stopped_hw_queues(q, true);
1155 else {
1156 spin_lock_irqsave(q->queue_lock, flags);
1157 blk_start_queue_async(q);
1158 spin_unlock_irqrestore(q->queue_lock, flags);
1159 }
1160 }
1161
1162 static bool cmd_report_zone(struct nullb *nullb, struct nullb_cmd *cmd)
1163 {
1164 struct nullb_device *dev = cmd->nq->dev;
1165
1166 if (dev->queue_mode == NULL_Q_BIO) {
1167 if (bio_op(cmd->bio) == REQ_OP_ZONE_REPORT) {
1168 cmd->error = null_zone_report(nullb, cmd->bio);
1169 return true;
1170 }
1171 } else {
1172 if (req_op(cmd->rq) == REQ_OP_ZONE_REPORT) {
1173 cmd->error = null_zone_report(nullb, cmd->rq->bio);
1174 return true;
1175 }
1176 }
1177
1178 return false;
1179 }
1180
1181 static blk_status_t null_handle_cmd(struct nullb_cmd *cmd)
1182 {
1183 struct nullb_device *dev = cmd->nq->dev;
1184 struct nullb *nullb = dev->nullb;
1185 int err = 0;
1186
1187 if (cmd_report_zone(nullb, cmd))
1188 goto out;
1189
1190 if (test_bit(NULLB_DEV_FL_THROTTLED, &dev->flags)) {
1191 struct request *rq = cmd->rq;
1192
1193 if (!hrtimer_active(&nullb->bw_timer))
1194 hrtimer_restart(&nullb->bw_timer);
1195
1196 if (atomic_long_sub_return(blk_rq_bytes(rq),
1197 &nullb->cur_bytes) < 0) {
1198 null_stop_queue(nullb);
1199 /* race with timer */
1200 if (atomic_long_read(&nullb->cur_bytes) > 0)
1201 null_restart_queue_async(nullb);
1202 if (dev->queue_mode == NULL_Q_RQ) {
1203 struct request_queue *q = nullb->q;
1204
1205 spin_lock_irq(q->queue_lock);
1206 rq->rq_flags |= RQF_DONTPREP;
1207 blk_requeue_request(q, rq);
1208 spin_unlock_irq(q->queue_lock);
1209 return BLK_STS_OK;
1210 } else
1211 /* requeue request */
1212 return BLK_STS_DEV_RESOURCE;
1213 }
1214 }
1215
1216 if (nullb->dev->badblocks.shift != -1) {
1217 int bad_sectors;
1218 sector_t sector, size, first_bad;
1219 bool is_flush = true;
1220
1221 if (dev->queue_mode == NULL_Q_BIO &&
1222 bio_op(cmd->bio) != REQ_OP_FLUSH) {
1223 is_flush = false;
1224 sector = cmd->bio->bi_iter.bi_sector;
1225 size = bio_sectors(cmd->bio);
1226 }
1227 if (dev->queue_mode != NULL_Q_BIO &&
1228 req_op(cmd->rq) != REQ_OP_FLUSH) {
1229 is_flush = false;
1230 sector = blk_rq_pos(cmd->rq);
1231 size = blk_rq_sectors(cmd->rq);
1232 }
1233 if (!is_flush && badblocks_check(&nullb->dev->badblocks, sector,
1234 size, &first_bad, &bad_sectors)) {
1235 cmd->error = BLK_STS_IOERR;
1236 goto out;
1237 }
1238 }
1239
1240 if (dev->memory_backed) {
1241 if (dev->queue_mode == NULL_Q_BIO) {
1242 if (bio_op(cmd->bio) == REQ_OP_FLUSH)
1243 err = null_handle_flush(nullb);
1244 else
1245 err = null_handle_bio(cmd);
1246 } else {
1247 if (req_op(cmd->rq) == REQ_OP_FLUSH)
1248 err = null_handle_flush(nullb);
1249 else
1250 err = null_handle_rq(cmd);
1251 }
1252 }
1253 cmd->error = errno_to_blk_status(err);
1254
1255 if (!cmd->error && dev->zoned) {
1256 sector_t sector;
1257 unsigned int nr_sectors;
1258 int op;
1259
1260 if (dev->queue_mode == NULL_Q_BIO) {
1261 op = bio_op(cmd->bio);
1262 sector = cmd->bio->bi_iter.bi_sector;
1263 nr_sectors = cmd->bio->bi_iter.bi_size >> 9;
1264 } else {
1265 op = req_op(cmd->rq);
1266 sector = blk_rq_pos(cmd->rq);
1267 nr_sectors = blk_rq_sectors(cmd->rq);
1268 }
1269
1270 if (op == REQ_OP_WRITE)
1271 null_zone_write(cmd, sector, nr_sectors);
1272 else if (op == REQ_OP_ZONE_RESET)
1273 null_zone_reset(cmd, sector);
1274 }
1275 out:
1276 /* Complete IO by inline, softirq or timer */
1277 switch (dev->irqmode) {
1278 case NULL_IRQ_SOFTIRQ:
1279 switch (dev->queue_mode) {
1280 case NULL_Q_MQ:
1281 blk_mq_complete_request(cmd->rq);
1282 break;
1283 case NULL_Q_RQ:
1284 blk_complete_request(cmd->rq);
1285 break;
1286 case NULL_Q_BIO:
1287 /*
1288 * XXX: no proper submitting cpu information available.
1289 */
1290 end_cmd(cmd);
1291 break;
1292 }
1293 break;
1294 case NULL_IRQ_NONE:
1295 end_cmd(cmd);
1296 break;
1297 case NULL_IRQ_TIMER:
1298 null_cmd_end_timer(cmd);
1299 break;
1300 }
1301 return BLK_STS_OK;
1302 }
1303
1304 static enum hrtimer_restart nullb_bwtimer_fn(struct hrtimer *timer)
1305 {
1306 struct nullb *nullb = container_of(timer, struct nullb, bw_timer);
1307 ktime_t timer_interval = ktime_set(0, TIMER_INTERVAL);
1308 unsigned int mbps = nullb->dev->mbps;
1309
1310 if (atomic_long_read(&nullb->cur_bytes) == mb_per_tick(mbps))
1311 return HRTIMER_NORESTART;
1312
1313 atomic_long_set(&nullb->cur_bytes, mb_per_tick(mbps));
1314 null_restart_queue_async(nullb);
1315
1316 hrtimer_forward_now(&nullb->bw_timer, timer_interval);
1317
1318 return HRTIMER_RESTART;
1319 }
1320
1321 static void nullb_setup_bwtimer(struct nullb *nullb)
1322 {
1323 ktime_t timer_interval = ktime_set(0, TIMER_INTERVAL);
1324
1325 hrtimer_init(&nullb->bw_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
1326 nullb->bw_timer.function = nullb_bwtimer_fn;
1327 atomic_long_set(&nullb->cur_bytes, mb_per_tick(nullb->dev->mbps));
1328 hrtimer_start(&nullb->bw_timer, timer_interval, HRTIMER_MODE_REL);
1329 }
1330
1331 static struct nullb_queue *nullb_to_queue(struct nullb *nullb)
1332 {
1333 int index = 0;
1334
1335 if (nullb->nr_queues != 1)
1336 index = raw_smp_processor_id() / ((nr_cpu_ids + nullb->nr_queues - 1) / nullb->nr_queues);
1337
1338 return &nullb->queues[index];
1339 }
1340
1341 static blk_qc_t null_queue_bio(struct request_queue *q, struct bio *bio)
1342 {
1343 struct nullb *nullb = q->queuedata;
1344 struct nullb_queue *nq = nullb_to_queue(nullb);
1345 struct nullb_cmd *cmd;
1346
1347 cmd = alloc_cmd(nq, 1);
1348 cmd->bio = bio;
1349
1350 null_handle_cmd(cmd);
1351 return BLK_QC_T_NONE;
1352 }
1353
1354 static enum blk_eh_timer_return null_rq_timed_out_fn(struct request *rq)
1355 {
1356 pr_info("null: rq %p timed out\n", rq);
1357 __blk_complete_request(rq);
1358 return BLK_EH_DONE;
1359 }
1360
1361 static int null_rq_prep_fn(struct request_queue *q, struct request *req)
1362 {
1363 struct nullb *nullb = q->queuedata;
1364 struct nullb_queue *nq = nullb_to_queue(nullb);
1365 struct nullb_cmd *cmd;
1366
1367 cmd = alloc_cmd(nq, 0);
1368 if (cmd) {
1369 cmd->rq = req;
1370 req->special = cmd;
1371 return BLKPREP_OK;
1372 }
1373 blk_stop_queue(q);
1374
1375 return BLKPREP_DEFER;
1376 }
1377
1378 static bool should_timeout_request(struct request *rq)
1379 {
1380 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
1381 if (g_timeout_str[0])
1382 return should_fail(&null_timeout_attr, 1);
1383 #endif
1384 return false;
1385 }
1386
1387 static bool should_requeue_request(struct request *rq)
1388 {
1389 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
1390 if (g_requeue_str[0])
1391 return should_fail(&null_requeue_attr, 1);
1392 #endif
1393 return false;
1394 }
1395
1396 static void null_request_fn(struct request_queue *q)
1397 {
1398 struct request *rq;
1399
1400 while ((rq = blk_fetch_request(q)) != NULL) {
1401 struct nullb_cmd *cmd = rq->special;
1402
1403 /* just ignore the request */
1404 if (should_timeout_request(rq))
1405 continue;
1406 if (should_requeue_request(rq)) {
1407 blk_requeue_request(q, rq);
1408 continue;
1409 }
1410
1411 spin_unlock_irq(q->queue_lock);
1412 null_handle_cmd(cmd);
1413 spin_lock_irq(q->queue_lock);
1414 }
1415 }
1416
1417 static enum blk_eh_timer_return null_timeout_rq(struct request *rq, bool res)
1418 {
1419 pr_info("null: rq %p timed out\n", rq);
1420 blk_mq_complete_request(rq);
1421 return BLK_EH_DONE;
1422 }
1423
1424 static blk_status_t null_queue_rq(struct blk_mq_hw_ctx *hctx,
1425 const struct blk_mq_queue_data *bd)
1426 {
1427 struct nullb_cmd *cmd = blk_mq_rq_to_pdu(bd->rq);
1428 struct nullb_queue *nq = hctx->driver_data;
1429
1430 might_sleep_if(hctx->flags & BLK_MQ_F_BLOCKING);
1431
1432 if (nq->dev->irqmode == NULL_IRQ_TIMER) {
1433 hrtimer_init(&cmd->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
1434 cmd->timer.function = null_cmd_timer_expired;
1435 }
1436 cmd->rq = bd->rq;
1437 cmd->error = BLK_STS_OK;
1438 cmd->nq = nq;
1439
1440 blk_mq_start_request(bd->rq);
1441
1442 if (should_requeue_request(bd->rq)) {
1443 /*
1444 * Alternate between hitting the core BUSY path, and the
1445 * driver driven requeue path
1446 */
1447 nq->requeue_selection++;
1448 if (nq->requeue_selection & 1)
1449 return BLK_STS_RESOURCE;
1450 else {
1451 blk_mq_requeue_request(bd->rq, true);
1452 return BLK_STS_OK;
1453 }
1454 }
1455 if (should_timeout_request(bd->rq))
1456 return BLK_STS_OK;
1457
1458 return null_handle_cmd(cmd);
1459 }
1460
1461 static const struct blk_mq_ops null_mq_ops = {
1462 .queue_rq = null_queue_rq,
1463 .complete = null_softirq_done_fn,
1464 .timeout = null_timeout_rq,
1465 };
1466
1467 static void cleanup_queue(struct nullb_queue *nq)
1468 {
1469 kfree(nq->tag_map);
1470 kfree(nq->cmds);
1471 }
1472
1473 static void cleanup_queues(struct nullb *nullb)
1474 {
1475 int i;
1476
1477 for (i = 0; i < nullb->nr_queues; i++)
1478 cleanup_queue(&nullb->queues[i]);
1479
1480 kfree(nullb->queues);
1481 }
1482
1483 static void null_del_dev(struct nullb *nullb)
1484 {
1485 struct nullb_device *dev;
1486
1487 if (!nullb)
1488 return;
1489
1490 dev = nullb->dev;
1491
1492 ida_simple_remove(&nullb_indexes, nullb->index);
1493
1494 list_del_init(&nullb->list);
1495
1496 del_gendisk(nullb->disk);
1497
1498 if (test_bit(NULLB_DEV_FL_THROTTLED, &nullb->dev->flags)) {
1499 hrtimer_cancel(&nullb->bw_timer);
1500 atomic_long_set(&nullb->cur_bytes, LONG_MAX);
1501 null_restart_queue_async(nullb);
1502 }
1503
1504 blk_cleanup_queue(nullb->q);
1505 if (dev->queue_mode == NULL_Q_MQ &&
1506 nullb->tag_set == &nullb->__tag_set)
1507 blk_mq_free_tag_set(nullb->tag_set);
1508 put_disk(nullb->disk);
1509 cleanup_queues(nullb);
1510 if (null_cache_active(nullb))
1511 null_free_device_storage(nullb->dev, true);
1512 kfree(nullb);
1513 dev->nullb = NULL;
1514 }
1515
1516 static void null_config_discard(struct nullb *nullb)
1517 {
1518 if (nullb->dev->discard == false)
1519 return;
1520 nullb->q->limits.discard_granularity = nullb->dev->blocksize;
1521 nullb->q->limits.discard_alignment = nullb->dev->blocksize;
1522 blk_queue_max_discard_sectors(nullb->q, UINT_MAX >> 9);
1523 blk_queue_flag_set(QUEUE_FLAG_DISCARD, nullb->q);
1524 }
1525
1526 static int null_open(struct block_device *bdev, fmode_t mode)
1527 {
1528 return 0;
1529 }
1530
1531 static void null_release(struct gendisk *disk, fmode_t mode)
1532 {
1533 }
1534
1535 static const struct block_device_operations null_fops = {
1536 .owner = THIS_MODULE,
1537 .open = null_open,
1538 .release = null_release,
1539 };
1540
1541 static void null_init_queue(struct nullb *nullb, struct nullb_queue *nq)
1542 {
1543 BUG_ON(!nullb);
1544 BUG_ON(!nq);
1545
1546 init_waitqueue_head(&nq->wait);
1547 nq->queue_depth = nullb->queue_depth;
1548 nq->dev = nullb->dev;
1549 }
1550
1551 static void null_init_queues(struct nullb *nullb)
1552 {
1553 struct request_queue *q = nullb->q;
1554 struct blk_mq_hw_ctx *hctx;
1555 struct nullb_queue *nq;
1556 int i;
1557
1558 queue_for_each_hw_ctx(q, hctx, i) {
1559 if (!hctx->nr_ctx || !hctx->tags)
1560 continue;
1561 nq = &nullb->queues[i];
1562 hctx->driver_data = nq;
1563 null_init_queue(nullb, nq);
1564 nullb->nr_queues++;
1565 }
1566 }
1567
1568 static int setup_commands(struct nullb_queue *nq)
1569 {
1570 struct nullb_cmd *cmd;
1571 int i, tag_size;
1572
1573 nq->cmds = kcalloc(nq->queue_depth, sizeof(*cmd), GFP_KERNEL);
1574 if (!nq->cmds)
1575 return -ENOMEM;
1576
1577 tag_size = ALIGN(nq->queue_depth, BITS_PER_LONG) / BITS_PER_LONG;
1578 nq->tag_map = kcalloc(tag_size, sizeof(unsigned long), GFP_KERNEL);
1579 if (!nq->tag_map) {
1580 kfree(nq->cmds);
1581 return -ENOMEM;
1582 }
1583
1584 for (i = 0; i < nq->queue_depth; i++) {
1585 cmd = &nq->cmds[i];
1586 INIT_LIST_HEAD(&cmd->list);
1587 cmd->ll_list.next = NULL;
1588 cmd->tag = -1U;
1589 }
1590
1591 return 0;
1592 }
1593
1594 static int setup_queues(struct nullb *nullb)
1595 {
1596 nullb->queues = kcalloc(nullb->dev->submit_queues,
1597 sizeof(struct nullb_queue),
1598 GFP_KERNEL);
1599 if (!nullb->queues)
1600 return -ENOMEM;
1601
1602 nullb->nr_queues = 0;
1603 nullb->queue_depth = nullb->dev->hw_queue_depth;
1604
1605 return 0;
1606 }
1607
1608 static int init_driver_queues(struct nullb *nullb)
1609 {
1610 struct nullb_queue *nq;
1611 int i, ret = 0;
1612
1613 for (i = 0; i < nullb->dev->submit_queues; i++) {
1614 nq = &nullb->queues[i];
1615
1616 null_init_queue(nullb, nq);
1617
1618 ret = setup_commands(nq);
1619 if (ret)
1620 return ret;
1621 nullb->nr_queues++;
1622 }
1623 return 0;
1624 }
1625
1626 static int null_gendisk_register(struct nullb *nullb)
1627 {
1628 struct gendisk *disk;
1629 sector_t size;
1630
1631 disk = nullb->disk = alloc_disk_node(1, nullb->dev->home_node);
1632 if (!disk)
1633 return -ENOMEM;
1634 size = (sector_t)nullb->dev->size * 1024 * 1024ULL;
1635 set_capacity(disk, size >> 9);
1636
1637 disk->flags |= GENHD_FL_EXT_DEVT | GENHD_FL_SUPPRESS_PARTITION_INFO;
1638 disk->major = null_major;
1639 disk->first_minor = nullb->index;
1640 disk->fops = &null_fops;
1641 disk->private_data = nullb;
1642 disk->queue = nullb->q;
1643 strncpy(disk->disk_name, nullb->disk_name, DISK_NAME_LEN);
1644
1645 add_disk(disk);
1646 return 0;
1647 }
1648
1649 static int null_init_tag_set(struct nullb *nullb, struct blk_mq_tag_set *set)
1650 {
1651 set->ops = &null_mq_ops;
1652 set->nr_hw_queues = nullb ? nullb->dev->submit_queues :
1653 g_submit_queues;
1654 set->queue_depth = nullb ? nullb->dev->hw_queue_depth :
1655 g_hw_queue_depth;
1656 set->numa_node = nullb ? nullb->dev->home_node : g_home_node;
1657 set->cmd_size = sizeof(struct nullb_cmd);
1658 set->flags = BLK_MQ_F_SHOULD_MERGE;
1659 if (g_no_sched)
1660 set->flags |= BLK_MQ_F_NO_SCHED;
1661 set->driver_data = NULL;
1662
1663 if ((nullb && nullb->dev->blocking) || g_blocking)
1664 set->flags |= BLK_MQ_F_BLOCKING;
1665
1666 return blk_mq_alloc_tag_set(set);
1667 }
1668
1669 static void null_validate_conf(struct nullb_device *dev)
1670 {
1671 dev->blocksize = round_down(dev->blocksize, 512);
1672 dev->blocksize = clamp_t(unsigned int, dev->blocksize, 512, 4096);
1673
1674 if (dev->queue_mode == NULL_Q_MQ && dev->use_per_node_hctx) {
1675 if (dev->submit_queues != nr_online_nodes)
1676 dev->submit_queues = nr_online_nodes;
1677 } else if (dev->submit_queues > nr_cpu_ids)
1678 dev->submit_queues = nr_cpu_ids;
1679 else if (dev->submit_queues == 0)
1680 dev->submit_queues = 1;
1681
1682 dev->queue_mode = min_t(unsigned int, dev->queue_mode, NULL_Q_MQ);
1683 dev->irqmode = min_t(unsigned int, dev->irqmode, NULL_IRQ_TIMER);
1684
1685 /* Do memory allocation, so set blocking */
1686 if (dev->memory_backed)
1687 dev->blocking = true;
1688 else /* cache is meaningless */
1689 dev->cache_size = 0;
1690 dev->cache_size = min_t(unsigned long, ULONG_MAX / 1024 / 1024,
1691 dev->cache_size);
1692 dev->mbps = min_t(unsigned int, 1024 * 40, dev->mbps);
1693 /* can not stop a queue */
1694 if (dev->queue_mode == NULL_Q_BIO)
1695 dev->mbps = 0;
1696 }
1697
1698 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
1699 static bool __null_setup_fault(struct fault_attr *attr, char *str)
1700 {
1701 if (!str[0])
1702 return true;
1703
1704 if (!setup_fault_attr(attr, str))
1705 return false;
1706
1707 attr->verbose = 0;
1708 return true;
1709 }
1710 #endif
1711
1712 static bool null_setup_fault(void)
1713 {
1714 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
1715 if (!__null_setup_fault(&null_timeout_attr, g_timeout_str))
1716 return false;
1717 if (!__null_setup_fault(&null_requeue_attr, g_requeue_str))
1718 return false;
1719 #endif
1720 return true;
1721 }
1722
1723 static int null_add_dev(struct nullb_device *dev)
1724 {
1725 struct nullb *nullb;
1726 int rv;
1727
1728 null_validate_conf(dev);
1729
1730 nullb = kzalloc_node(sizeof(*nullb), GFP_KERNEL, dev->home_node);
1731 if (!nullb) {
1732 rv = -ENOMEM;
1733 goto out;
1734 }
1735 nullb->dev = dev;
1736 dev->nullb = nullb;
1737
1738 spin_lock_init(&nullb->lock);
1739
1740 rv = setup_queues(nullb);
1741 if (rv)
1742 goto out_free_nullb;
1743
1744 if (dev->queue_mode == NULL_Q_MQ) {
1745 if (shared_tags) {
1746 nullb->tag_set = &tag_set;
1747 rv = 0;
1748 } else {
1749 nullb->tag_set = &nullb->__tag_set;
1750 rv = null_init_tag_set(nullb, nullb->tag_set);
1751 }
1752
1753 if (rv)
1754 goto out_cleanup_queues;
1755
1756 if (!null_setup_fault())
1757 goto out_cleanup_queues;
1758
1759 nullb->tag_set->timeout = 5 * HZ;
1760 nullb->q = blk_mq_init_queue(nullb->tag_set);
1761 if (IS_ERR(nullb->q)) {
1762 rv = -ENOMEM;
1763 goto out_cleanup_tags;
1764 }
1765 null_init_queues(nullb);
1766 } else if (dev->queue_mode == NULL_Q_BIO) {
1767 nullb->q = blk_alloc_queue_node(GFP_KERNEL, dev->home_node,
1768 NULL);
1769 if (!nullb->q) {
1770 rv = -ENOMEM;
1771 goto out_cleanup_queues;
1772 }
1773 blk_queue_make_request(nullb->q, null_queue_bio);
1774 rv = init_driver_queues(nullb);
1775 if (rv)
1776 goto out_cleanup_blk_queue;
1777 } else {
1778 nullb->q = blk_init_queue_node(null_request_fn, &nullb->lock,
1779 dev->home_node);
1780 if (!nullb->q) {
1781 rv = -ENOMEM;
1782 goto out_cleanup_queues;
1783 }
1784
1785 if (!null_setup_fault())
1786 goto out_cleanup_blk_queue;
1787
1788 blk_queue_prep_rq(nullb->q, null_rq_prep_fn);
1789 blk_queue_softirq_done(nullb->q, null_softirq_done_fn);
1790 blk_queue_rq_timed_out(nullb->q, null_rq_timed_out_fn);
1791 nullb->q->rq_timeout = 5 * HZ;
1792 rv = init_driver_queues(nullb);
1793 if (rv)
1794 goto out_cleanup_blk_queue;
1795 }
1796
1797 if (dev->mbps) {
1798 set_bit(NULLB_DEV_FL_THROTTLED, &dev->flags);
1799 nullb_setup_bwtimer(nullb);
1800 }
1801
1802 if (dev->cache_size > 0) {
1803 set_bit(NULLB_DEV_FL_CACHE, &nullb->dev->flags);
1804 blk_queue_write_cache(nullb->q, true, true);
1805 blk_queue_flush_queueable(nullb->q, true);
1806 }
1807
1808 if (dev->zoned) {
1809 rv = null_zone_init(dev);
1810 if (rv)
1811 goto out_cleanup_blk_queue;
1812
1813 blk_queue_chunk_sectors(nullb->q, dev->zone_size_sects);
1814 nullb->q->limits.zoned = BLK_ZONED_HM;
1815 }
1816
1817 nullb->q->queuedata = nullb;
1818 blk_queue_flag_set(QUEUE_FLAG_NONROT, nullb->q);
1819 blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, nullb->q);
1820
1821 mutex_lock(&lock);
1822 nullb->index = ida_simple_get(&nullb_indexes, 0, 0, GFP_KERNEL);
1823 dev->index = nullb->index;
1824 mutex_unlock(&lock);
1825
1826 blk_queue_logical_block_size(nullb->q, dev->blocksize);
1827 blk_queue_physical_block_size(nullb->q, dev->blocksize);
1828
1829 null_config_discard(nullb);
1830
1831 sprintf(nullb->disk_name, "nullb%d", nullb->index);
1832
1833 rv = null_gendisk_register(nullb);
1834 if (rv)
1835 goto out_cleanup_zone;
1836
1837 mutex_lock(&lock);
1838 list_add_tail(&nullb->list, &nullb_list);
1839 mutex_unlock(&lock);
1840
1841 return 0;
1842 out_cleanup_zone:
1843 if (dev->zoned)
1844 null_zone_exit(dev);
1845 out_cleanup_blk_queue:
1846 blk_cleanup_queue(nullb->q);
1847 out_cleanup_tags:
1848 if (dev->queue_mode == NULL_Q_MQ && nullb->tag_set == &nullb->__tag_set)
1849 blk_mq_free_tag_set(nullb->tag_set);
1850 out_cleanup_queues:
1851 cleanup_queues(nullb);
1852 out_free_nullb:
1853 kfree(nullb);
1854 dev->nullb = NULL;
1855 out:
1856 return rv;
1857 }
1858
1859 static int __init null_init(void)
1860 {
1861 int ret = 0;
1862 unsigned int i;
1863 struct nullb *nullb;
1864 struct nullb_device *dev;
1865
1866 if (g_bs > PAGE_SIZE) {
1867 pr_warn("null_blk: invalid block size\n");
1868 pr_warn("null_blk: defaults block size to %lu\n", PAGE_SIZE);
1869 g_bs = PAGE_SIZE;
1870 }
1871
1872 if (!is_power_of_2(g_zone_size)) {
1873 pr_err("null_blk: zone_size must be power-of-two\n");
1874 return -EINVAL;
1875 }
1876
1877 if (g_queue_mode == NULL_Q_MQ && g_use_per_node_hctx) {
1878 if (g_submit_queues != nr_online_nodes) {
1879 pr_warn("null_blk: submit_queues param is set to %u.\n",
1880 nr_online_nodes);
1881 g_submit_queues = nr_online_nodes;
1882 }
1883 } else if (g_submit_queues > nr_cpu_ids)
1884 g_submit_queues = nr_cpu_ids;
1885 else if (g_submit_queues <= 0)
1886 g_submit_queues = 1;
1887
1888 if (g_queue_mode == NULL_Q_MQ && shared_tags) {
1889 ret = null_init_tag_set(NULL, &tag_set);
1890 if (ret)
1891 return ret;
1892 }
1893
1894 config_group_init(&nullb_subsys.su_group);
1895 mutex_init(&nullb_subsys.su_mutex);
1896
1897 ret = configfs_register_subsystem(&nullb_subsys);
1898 if (ret)
1899 goto err_tagset;
1900
1901 mutex_init(&lock);
1902
1903 null_major = register_blkdev(0, "nullb");
1904 if (null_major < 0) {
1905 ret = null_major;
1906 goto err_conf;
1907 }
1908
1909 for (i = 0; i < nr_devices; i++) {
1910 dev = null_alloc_dev();
1911 if (!dev) {
1912 ret = -ENOMEM;
1913 goto err_dev;
1914 }
1915 ret = null_add_dev(dev);
1916 if (ret) {
1917 null_free_dev(dev);
1918 goto err_dev;
1919 }
1920 }
1921
1922 pr_info("null: module loaded\n");
1923 return 0;
1924
1925 err_dev:
1926 while (!list_empty(&nullb_list)) {
1927 nullb = list_entry(nullb_list.next, struct nullb, list);
1928 dev = nullb->dev;
1929 null_del_dev(nullb);
1930 null_free_dev(dev);
1931 }
1932 unregister_blkdev(null_major, "nullb");
1933 err_conf:
1934 configfs_unregister_subsystem(&nullb_subsys);
1935 err_tagset:
1936 if (g_queue_mode == NULL_Q_MQ && shared_tags)
1937 blk_mq_free_tag_set(&tag_set);
1938 return ret;
1939 }
1940
1941 static void __exit null_exit(void)
1942 {
1943 struct nullb *nullb;
1944
1945 configfs_unregister_subsystem(&nullb_subsys);
1946
1947 unregister_blkdev(null_major, "nullb");
1948
1949 mutex_lock(&lock);
1950 while (!list_empty(&nullb_list)) {
1951 struct nullb_device *dev;
1952
1953 nullb = list_entry(nullb_list.next, struct nullb, list);
1954 dev = nullb->dev;
1955 null_del_dev(nullb);
1956 null_free_dev(dev);
1957 }
1958 mutex_unlock(&lock);
1959
1960 if (g_queue_mode == NULL_Q_MQ && shared_tags)
1961 blk_mq_free_tag_set(&tag_set);
1962 }
1963
1964 module_init(null_init);
1965 module_exit(null_exit);
1966
1967 MODULE_AUTHOR("Jens Axboe <axboe@kernel.dk>");
1968 MODULE_LICENSE("GPL");
Linux with added FPC-III support