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perf tools: Streamline bpf examples and headers installation
[linux/fpc-iii.git] / drivers / block / null_blk.c
blob042c778e5a4e0bf2009c38a6b1cf37bc5d23ce89
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/blkdev.h>
11 #include <linux/init.h>
12 #include <linux/slab.h>
13 #include <linux/blk-mq.h>
14 #include <linux/hrtimer.h>
15 #include <linux/configfs.h>
16 #include <linux/badblocks.h>
17 #include <linux/fault-inject.h>
18
19 #define PAGE_SECTORS_SHIFT (PAGE_SHIFT - SECTOR_SHIFT)
20 #define PAGE_SECTORS (1 << PAGE_SECTORS_SHIFT)
21 #define SECTOR_MASK (PAGE_SECTORS - 1)
22
23 #define FREE_BATCH 16
24
25 #define TICKS_PER_SEC 50ULL
26 #define TIMER_INTERVAL (NSEC_PER_SEC / TICKS_PER_SEC)
27
28 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
29 static DECLARE_FAULT_ATTR(null_timeout_attr);
30 static DECLARE_FAULT_ATTR(null_requeue_attr);
31 #endif
32
33 static inline u64 mb_per_tick(int mbps)
34 {
35 return (1 << 20) / TICKS_PER_SEC * ((u64) mbps);
36 }
37
38 struct nullb_cmd {
39 struct list_head list;
40 struct llist_node ll_list;
41 struct __call_single_data csd;
42 struct request *rq;
43 struct bio *bio;
44 unsigned int tag;
45 blk_status_t error;
46 struct nullb_queue *nq;
47 struct hrtimer timer;
48 };
49
50 struct nullb_queue {
51 unsigned long *tag_map;
52 wait_queue_head_t wait;
53 unsigned int queue_depth;
54 struct nullb_device *dev;
55 unsigned int requeue_selection;
56
57 struct nullb_cmd *cmds;
58 };
59
60 /*
61 * Status flags for nullb_device.
62 *
63 * CONFIGURED: Device has been configured and turned on. Cannot reconfigure.
64 * UP: Device is currently on and visible in userspace.
65 * THROTTLED: Device is being throttled.
66 * CACHE: Device is using a write-back cache.
67 */
68 enum nullb_device_flags {
69 NULLB_DEV_FL_CONFIGURED = 0,
70 NULLB_DEV_FL_UP = 1,
71 NULLB_DEV_FL_THROTTLED = 2,
72 NULLB_DEV_FL_CACHE = 3,
73 };
74
75 #define MAP_SZ ((PAGE_SIZE >> SECTOR_SHIFT) + 2)
76 /*
77 * nullb_page is a page in memory for nullb devices.
78 *
79 * @page: The page holding the data.
80 * @bitmap: The bitmap represents which sector in the page has data.
81 * Each bit represents one block size. For example, sector 8
82 * will use the 7th bit
83 * The highest 2 bits of bitmap are for special purpose. LOCK means the cache
84 * page is being flushing to storage. FREE means the cache page is freed and
85 * should be skipped from flushing to storage. Please see
86 * null_make_cache_space
87 */
88 struct nullb_page {
89 struct page *page;
90 DECLARE_BITMAP(bitmap, MAP_SZ);
91 };
92 #define NULLB_PAGE_LOCK (MAP_SZ - 1)
93 #define NULLB_PAGE_FREE (MAP_SZ - 2)
94
95 struct nullb_device {
96 struct nullb *nullb;
97 struct config_item item;
98 struct radix_tree_root data; /* data stored in the disk */
99 struct radix_tree_root cache; /* disk cache data */
100 unsigned long flags; /* device flags */
101 unsigned int curr_cache;
102 struct badblocks badblocks;
103
104 unsigned long size; /* device size in MB */
105 unsigned long completion_nsec; /* time in ns to complete a request */
106 unsigned long cache_size; /* disk cache size in MB */
107 unsigned int submit_queues; /* number of submission queues */
108 unsigned int home_node; /* home node for the device */
109 unsigned int queue_mode; /* block interface */
110 unsigned int blocksize; /* block size */
111 unsigned int irqmode; /* IRQ completion handler */
112 unsigned int hw_queue_depth; /* queue depth */
113 unsigned int index; /* index of the disk, only valid with a disk */
114 unsigned int mbps; /* Bandwidth throttle cap (in MB/s) */
115 bool blocking; /* blocking blk-mq device */
116 bool use_per_node_hctx; /* use per-node allocation for hardware context */
117 bool power; /* power on/off the device */
118 bool memory_backed; /* if data is stored in memory */
119 bool discard; /* if support discard */
120 };
121
122 struct nullb {
123 struct nullb_device *dev;
124 struct list_head list;
125 unsigned int index;
126 struct request_queue *q;
127 struct gendisk *disk;
128 struct blk_mq_tag_set *tag_set;
129 struct blk_mq_tag_set __tag_set;
130 unsigned int queue_depth;
131 atomic_long_t cur_bytes;
132 struct hrtimer bw_timer;
133 unsigned long cache_flush_pos;
134 spinlock_t lock;
135
136 struct nullb_queue *queues;
137 unsigned int nr_queues;
138 char disk_name[DISK_NAME_LEN];
139 };
140
141 static LIST_HEAD(nullb_list);
142 static struct mutex lock;
143 static int null_major;
144 static DEFINE_IDA(nullb_indexes);
145 static struct blk_mq_tag_set tag_set;
146
147 enum {
148 NULL_IRQ_NONE = 0,
149 NULL_IRQ_SOFTIRQ = 1,
150 NULL_IRQ_TIMER = 2,
151 };
152
153 enum {
154 NULL_Q_BIO = 0,
155 NULL_Q_RQ = 1,
156 NULL_Q_MQ = 2,
157 };
158
159 static int g_no_sched;
160 module_param_named(no_sched, g_no_sched, int, 0444);
161 MODULE_PARM_DESC(no_sched, "No io scheduler");
162
163 static int g_submit_queues = 1;
164 module_param_named(submit_queues, g_submit_queues, int, 0444);
165 MODULE_PARM_DESC(submit_queues, "Number of submission queues");
166
167 static int g_home_node = NUMA_NO_NODE;
168 module_param_named(home_node, g_home_node, int, 0444);
169 MODULE_PARM_DESC(home_node, "Home node for the device");
170
171 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
172 static char g_timeout_str[80];
173 module_param_string(timeout, g_timeout_str, sizeof(g_timeout_str), 0444);
174
175 static char g_requeue_str[80];
176 module_param_string(requeue, g_requeue_str, sizeof(g_requeue_str), 0444);
177 #endif
178
179 static int g_queue_mode = NULL_Q_MQ;
180
181 static int null_param_store_val(const char *str, int *val, int min, int max)
182 {
183 int ret, new_val;
184
185 ret = kstrtoint(str, 10, &new_val);
186 if (ret)
187 return -EINVAL;
188
189 if (new_val < min || new_val > max)
190 return -EINVAL;
191
192 *val = new_val;
193 return 0;
194 }
195
196 static int null_set_queue_mode(const char *str, const struct kernel_param *kp)
197 {
198 return null_param_store_val(str, &g_queue_mode, NULL_Q_BIO, NULL_Q_MQ);
199 }
200
201 static const struct kernel_param_ops null_queue_mode_param_ops = {
202 .set = null_set_queue_mode,
203 .get = param_get_int,
204 };
205
206 device_param_cb(queue_mode, &null_queue_mode_param_ops, &g_queue_mode, 0444);
207 MODULE_PARM_DESC(queue_mode, "Block interface to use (0=bio,1=rq,2=multiqueue)");
208
209 static int g_gb = 250;
210 module_param_named(gb, g_gb, int, 0444);
211 MODULE_PARM_DESC(gb, "Size in GB");
212
213 static int g_bs = 512;
214 module_param_named(bs, g_bs, int, 0444);
215 MODULE_PARM_DESC(bs, "Block size (in bytes)");
216
217 static int nr_devices = 1;
218 module_param(nr_devices, int, 0444);
219 MODULE_PARM_DESC(nr_devices, "Number of devices to register");
220
221 static bool g_blocking;
222 module_param_named(blocking, g_blocking, bool, 0444);
223 MODULE_PARM_DESC(blocking, "Register as a blocking blk-mq driver device");
224
225 static bool shared_tags;
226 module_param(shared_tags, bool, 0444);
227 MODULE_PARM_DESC(shared_tags, "Share tag set between devices for blk-mq");
228
229 static int g_irqmode = NULL_IRQ_SOFTIRQ;
230
231 static int null_set_irqmode(const char *str, const struct kernel_param *kp)
232 {
233 return null_param_store_val(str, &g_irqmode, NULL_IRQ_NONE,
234 NULL_IRQ_TIMER);
235 }
236
237 static const struct kernel_param_ops null_irqmode_param_ops = {
238 .set = null_set_irqmode,
239 .get = param_get_int,
240 };
241
242 device_param_cb(irqmode, &null_irqmode_param_ops, &g_irqmode, 0444);
243 MODULE_PARM_DESC(irqmode, "IRQ completion handler. 0-none, 1-softirq, 2-timer");
244
245 static unsigned long g_completion_nsec = 10000;
246 module_param_named(completion_nsec, g_completion_nsec, ulong, 0444);
247 MODULE_PARM_DESC(completion_nsec, "Time in ns to complete a request in hardware. Default: 10,000ns");
248
249 static int g_hw_queue_depth = 64;
250 module_param_named(hw_queue_depth, g_hw_queue_depth, int, 0444);
251 MODULE_PARM_DESC(hw_queue_depth, "Queue depth for each hardware queue. Default: 64");
252
253 static bool g_use_per_node_hctx;
254 module_param_named(use_per_node_hctx, g_use_per_node_hctx, bool, 0444);
255 MODULE_PARM_DESC(use_per_node_hctx, "Use per-node allocation for hardware context queues. Default: false");
256
257 static struct nullb_device *null_alloc_dev(void);
258 static void null_free_dev(struct nullb_device *dev);
259 static void null_del_dev(struct nullb *nullb);
260 static int null_add_dev(struct nullb_device *dev);
261 static void null_free_device_storage(struct nullb_device *dev, bool is_cache);
262
263 static inline struct nullb_device *to_nullb_device(struct config_item *item)
264 {
265 return item ? container_of(item, struct nullb_device, item) : NULL;
266 }
267
268 static inline ssize_t nullb_device_uint_attr_show(unsigned int val, char *page)
269 {
270 return snprintf(page, PAGE_SIZE, "%u\n", val);
271 }
272
273 static inline ssize_t nullb_device_ulong_attr_show(unsigned long val,
274 char *page)
275 {
276 return snprintf(page, PAGE_SIZE, "%lu\n", val);
277 }
278
279 static inline ssize_t nullb_device_bool_attr_show(bool val, char *page)
280 {
281 return snprintf(page, PAGE_SIZE, "%u\n", val);
282 }
283
284 static ssize_t nullb_device_uint_attr_store(unsigned int *val,
285 const char *page, size_t count)
286 {
287 unsigned int tmp;
288 int result;
289
290 result = kstrtouint(page, 0, &tmp);
291 if (result)
292 return result;
293
294 *val = tmp;
295 return count;
296 }
297
298 static ssize_t nullb_device_ulong_attr_store(unsigned long *val,
299 const char *page, size_t count)
300 {
301 int result;
302 unsigned long tmp;
303
304 result = kstrtoul(page, 0, &tmp);
305 if (result)
306 return result;
307
308 *val = tmp;
309 return count;
310 }
311
312 static ssize_t nullb_device_bool_attr_store(bool *val, const char *page,
313 size_t count)
314 {
315 bool tmp;
316 int result;
317
318 result = kstrtobool(page, &tmp);
319 if (result)
320 return result;
321
322 *val = tmp;
323 return count;
324 }
325
326 /* The following macro should only be used with TYPE = {uint, ulong, bool}. */
327 #define NULLB_DEVICE_ATTR(NAME, TYPE) \
328 static ssize_t \
329 nullb_device_##NAME##_show(struct config_item *item, char *page) \
330 { \
331 return nullb_device_##TYPE##_attr_show( \
332 to_nullb_device(item)->NAME, page); \
333 } \
334 static ssize_t \
335 nullb_device_##NAME##_store(struct config_item *item, const char *page, \
336 size_t count) \
337 { \
338 if (test_bit(NULLB_DEV_FL_CONFIGURED, &to_nullb_device(item)->flags)) \
339 return -EBUSY; \
340 return nullb_device_##TYPE##_attr_store( \
341 &to_nullb_device(item)->NAME, page, count); \
342 } \
343 CONFIGFS_ATTR(nullb_device_, NAME);
344
345 NULLB_DEVICE_ATTR(size, ulong);
346 NULLB_DEVICE_ATTR(completion_nsec, ulong);
347 NULLB_DEVICE_ATTR(submit_queues, uint);
348 NULLB_DEVICE_ATTR(home_node, uint);
349 NULLB_DEVICE_ATTR(queue_mode, uint);
350 NULLB_DEVICE_ATTR(blocksize, uint);
351 NULLB_DEVICE_ATTR(irqmode, uint);
352 NULLB_DEVICE_ATTR(hw_queue_depth, uint);
353 NULLB_DEVICE_ATTR(index, uint);
354 NULLB_DEVICE_ATTR(blocking, bool);
355 NULLB_DEVICE_ATTR(use_per_node_hctx, bool);
356 NULLB_DEVICE_ATTR(memory_backed, bool);
357 NULLB_DEVICE_ATTR(discard, bool);
358 NULLB_DEVICE_ATTR(mbps, uint);
359 NULLB_DEVICE_ATTR(cache_size, ulong);
360
361 static ssize_t nullb_device_power_show(struct config_item *item, char *page)
362 {
363 return nullb_device_bool_attr_show(to_nullb_device(item)->power, page);
364 }
365
366 static ssize_t nullb_device_power_store(struct config_item *item,
367 const char *page, size_t count)
368 {
369 struct nullb_device *dev = to_nullb_device(item);
370 bool newp = false;
371 ssize_t ret;
372
373 ret = nullb_device_bool_attr_store(&newp, page, count);
374 if (ret < 0)
375 return ret;
376
377 if (!dev->power && newp) {
378 if (test_and_set_bit(NULLB_DEV_FL_UP, &dev->flags))
379 return count;
380 if (null_add_dev(dev)) {
381 clear_bit(NULLB_DEV_FL_UP, &dev->flags);
382 return -ENOMEM;
383 }
384
385 set_bit(NULLB_DEV_FL_CONFIGURED, &dev->flags);
386 dev->power = newp;
387 } else if (dev->power && !newp) {
388 mutex_lock(&lock);
389 dev->power = newp;
390 null_del_dev(dev->nullb);
391 mutex_unlock(&lock);
392 clear_bit(NULLB_DEV_FL_UP, &dev->flags);
393 }
394
395 return count;
396 }
397
398 CONFIGFS_ATTR(nullb_device_, power);
399
400 static ssize_t nullb_device_badblocks_show(struct config_item *item, char *page)
401 {
402 struct nullb_device *t_dev = to_nullb_device(item);
403
404 return badblocks_show(&t_dev->badblocks, page, 0);
405 }
406
407 static ssize_t nullb_device_badblocks_store(struct config_item *item,
408 const char *page, size_t count)
409 {
410 struct nullb_device *t_dev = to_nullb_device(item);
411 char *orig, *buf, *tmp;
412 u64 start, end;
413 int ret;
414
415 orig = kstrndup(page, count, GFP_KERNEL);
416 if (!orig)
417 return -ENOMEM;
418
419 buf = strstrip(orig);
420
421 ret = -EINVAL;
422 if (buf[0] != '+' && buf[0] != '-')
423 goto out;
424 tmp = strchr(&buf[1], '-');
425 if (!tmp)
426 goto out;
427 *tmp = '\0';
428 ret = kstrtoull(buf + 1, 0, &start);
429 if (ret)
430 goto out;
431 ret = kstrtoull(tmp + 1, 0, &end);
432 if (ret)
433 goto out;
434 ret = -EINVAL;
435 if (start > end)
436 goto out;
437 /* enable badblocks */
438 cmpxchg(&t_dev->badblocks.shift, -1, 0);
439 if (buf[0] == '+')
440 ret = badblocks_set(&t_dev->badblocks, start,
441 end - start + 1, 1);
442 else
443 ret = badblocks_clear(&t_dev->badblocks, start,
444 end - start + 1);
445 if (ret == 0)
446 ret = count;
447 out:
448 kfree(orig);
449 return ret;
450 }
451 CONFIGFS_ATTR(nullb_device_, badblocks);
452
453 static struct configfs_attribute *nullb_device_attrs[] = {
454 &nullb_device_attr_size,
455 &nullb_device_attr_completion_nsec,
456 &nullb_device_attr_submit_queues,
457 &nullb_device_attr_home_node,
458 &nullb_device_attr_queue_mode,
459 &nullb_device_attr_blocksize,
460 &nullb_device_attr_irqmode,
461 &nullb_device_attr_hw_queue_depth,
462 &nullb_device_attr_index,
463 &nullb_device_attr_blocking,
464 &nullb_device_attr_use_per_node_hctx,
465 &nullb_device_attr_power,
466 &nullb_device_attr_memory_backed,
467 &nullb_device_attr_discard,
468 &nullb_device_attr_mbps,
469 &nullb_device_attr_cache_size,
470 &nullb_device_attr_badblocks,
471 NULL,
472 };
473
474 static void nullb_device_release(struct config_item *item)
475 {
476 struct nullb_device *dev = to_nullb_device(item);
477
478 null_free_device_storage(dev, false);
479 null_free_dev(dev);
480 }
481
482 static struct configfs_item_operations nullb_device_ops = {
483 .release = nullb_device_release,
484 };
485
486 static const struct config_item_type nullb_device_type = {
487 .ct_item_ops = &nullb_device_ops,
488 .ct_attrs = nullb_device_attrs,
489 .ct_owner = THIS_MODULE,
490 };
491
492 static struct
493 config_item *nullb_group_make_item(struct config_group *group, const char *name)
494 {
495 struct nullb_device *dev;
496
497 dev = null_alloc_dev();
498 if (!dev)
499 return ERR_PTR(-ENOMEM);
500
501 config_item_init_type_name(&dev->item, name, &nullb_device_type);
502
503 return &dev->item;
504 }
505
506 static void
507 nullb_group_drop_item(struct config_group *group, struct config_item *item)
508 {
509 struct nullb_device *dev = to_nullb_device(item);
510
511 if (test_and_clear_bit(NULLB_DEV_FL_UP, &dev->flags)) {
512 mutex_lock(&lock);
513 dev->power = false;
514 null_del_dev(dev->nullb);
515 mutex_unlock(&lock);
516 }
517
518 config_item_put(item);
519 }
520
521 static ssize_t memb_group_features_show(struct config_item *item, char *page)
522 {
523 return snprintf(page, PAGE_SIZE, "memory_backed,discard,bandwidth,cache,badblocks\n");
524 }
525
526 CONFIGFS_ATTR_RO(memb_group_, features);
527
528 static struct configfs_attribute *nullb_group_attrs[] = {
529 &memb_group_attr_features,
530 NULL,
531 };
532
533 static struct configfs_group_operations nullb_group_ops = {
534 .make_item = nullb_group_make_item,
535 .drop_item = nullb_group_drop_item,
536 };
537
538 static const struct config_item_type nullb_group_type = {
539 .ct_group_ops = &nullb_group_ops,
540 .ct_attrs = nullb_group_attrs,
541 .ct_owner = THIS_MODULE,
542 };
543
544 static struct configfs_subsystem nullb_subsys = {
545 .su_group = {
546 .cg_item = {
547 .ci_namebuf = "nullb",
548 .ci_type = &nullb_group_type,
549 },
550 },
551 };
552
553 static inline int null_cache_active(struct nullb *nullb)
554 {
555 return test_bit(NULLB_DEV_FL_CACHE, &nullb->dev->flags);
556 }
557
558 static struct nullb_device *null_alloc_dev(void)
559 {
560 struct nullb_device *dev;
561
562 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
563 if (!dev)
564 return NULL;
565 INIT_RADIX_TREE(&dev->data, GFP_ATOMIC);
566 INIT_RADIX_TREE(&dev->cache, GFP_ATOMIC);
567 if (badblocks_init(&dev->badblocks, 0)) {
568 kfree(dev);
569 return NULL;
570 }
571
572 dev->size = g_gb * 1024;
573 dev->completion_nsec = g_completion_nsec;
574 dev->submit_queues = g_submit_queues;
575 dev->home_node = g_home_node;
576 dev->queue_mode = g_queue_mode;
577 dev->blocksize = g_bs;
578 dev->irqmode = g_irqmode;
579 dev->hw_queue_depth = g_hw_queue_depth;
580 dev->blocking = g_blocking;
581 dev->use_per_node_hctx = g_use_per_node_hctx;
582 return dev;
583 }
584
585 static void null_free_dev(struct nullb_device *dev)
586 {
587 if (!dev)
588 return;
589
590 badblocks_exit(&dev->badblocks);
591 kfree(dev);
592 }
593
594 static void put_tag(struct nullb_queue *nq, unsigned int tag)
595 {
596 clear_bit_unlock(tag, nq->tag_map);
597
598 if (waitqueue_active(&nq->wait))
599 wake_up(&nq->wait);
600 }
601
602 static unsigned int get_tag(struct nullb_queue *nq)
603 {
604 unsigned int tag;
605
606 do {
607 tag = find_first_zero_bit(nq->tag_map, nq->queue_depth);
608 if (tag >= nq->queue_depth)
609 return -1U;
610 } while (test_and_set_bit_lock(tag, nq->tag_map));
611
612 return tag;
613 }
614
615 static void free_cmd(struct nullb_cmd *cmd)
616 {
617 put_tag(cmd->nq, cmd->tag);
618 }
619
620 static enum hrtimer_restart null_cmd_timer_expired(struct hrtimer *timer);
621
622 static struct nullb_cmd *__alloc_cmd(struct nullb_queue *nq)
623 {
624 struct nullb_cmd *cmd;
625 unsigned int tag;
626
627 tag = get_tag(nq);
628 if (tag != -1U) {
629 cmd = &nq->cmds[tag];
630 cmd->tag = tag;
631 cmd->nq = nq;
632 if (nq->dev->irqmode == NULL_IRQ_TIMER) {
633 hrtimer_init(&cmd->timer, CLOCK_MONOTONIC,
634 HRTIMER_MODE_REL);
635 cmd->timer.function = null_cmd_timer_expired;
636 }
637 return cmd;
638 }
639
640 return NULL;
641 }
642
643 static struct nullb_cmd *alloc_cmd(struct nullb_queue *nq, int can_wait)
644 {
645 struct nullb_cmd *cmd;
646 DEFINE_WAIT(wait);
647
648 cmd = __alloc_cmd(nq);
649 if (cmd || !can_wait)
650 return cmd;
651
652 do {
653 prepare_to_wait(&nq->wait, &wait, TASK_UNINTERRUPTIBLE);
654 cmd = __alloc_cmd(nq);
655 if (cmd)
656 break;
657
658 io_schedule();
659 } while (1);
660
661 finish_wait(&nq->wait, &wait);
662 return cmd;
663 }
664
665 static void end_cmd(struct nullb_cmd *cmd)
666 {
667 struct request_queue *q = NULL;
668 int queue_mode = cmd->nq->dev->queue_mode;
669
670 if (cmd->rq)
671 q = cmd->rq->q;
672
673 switch (queue_mode) {
674 case NULL_Q_MQ:
675 blk_mq_end_request(cmd->rq, cmd->error);
676 return;
677 case NULL_Q_RQ:
678 INIT_LIST_HEAD(&cmd->rq->queuelist);
679 blk_end_request_all(cmd->rq, cmd->error);
680 break;
681 case NULL_Q_BIO:
682 cmd->bio->bi_status = cmd->error;
683 bio_endio(cmd->bio);
684 break;
685 }
686
687 free_cmd(cmd);
688
689 /* Restart queue if needed, as we are freeing a tag */
690 if (queue_mode == NULL_Q_RQ && blk_queue_stopped(q)) {
691 unsigned long flags;
692
693 spin_lock_irqsave(q->queue_lock, flags);
694 blk_start_queue_async(q);
695 spin_unlock_irqrestore(q->queue_lock, flags);
696 }
697 }
698
699 static enum hrtimer_restart null_cmd_timer_expired(struct hrtimer *timer)
700 {
701 end_cmd(container_of(timer, struct nullb_cmd, timer));
702
703 return HRTIMER_NORESTART;
704 }
705
706 static void null_cmd_end_timer(struct nullb_cmd *cmd)
707 {
708 ktime_t kt = cmd->nq->dev->completion_nsec;
709
710 hrtimer_start(&cmd->timer, kt, HRTIMER_MODE_REL);
711 }
712
713 static void null_softirq_done_fn(struct request *rq)
714 {
715 struct nullb *nullb = rq->q->queuedata;
716
717 if (nullb->dev->queue_mode == NULL_Q_MQ)
718 end_cmd(blk_mq_rq_to_pdu(rq));
719 else
720 end_cmd(rq->special);
721 }
722
723 static struct nullb_page *null_alloc_page(gfp_t gfp_flags)
724 {
725 struct nullb_page *t_page;
726
727 t_page = kmalloc(sizeof(struct nullb_page), gfp_flags);
728 if (!t_page)
729 goto out;
730
731 t_page->page = alloc_pages(gfp_flags, 0);
732 if (!t_page->page)
733 goto out_freepage;
734
735 memset(t_page->bitmap, 0, sizeof(t_page->bitmap));
736 return t_page;
737 out_freepage:
738 kfree(t_page);
739 out:
740 return NULL;
741 }
742
743 static void null_free_page(struct nullb_page *t_page)
744 {
745 __set_bit(NULLB_PAGE_FREE, t_page->bitmap);
746 if (test_bit(NULLB_PAGE_LOCK, t_page->bitmap))
747 return;
748 __free_page(t_page->page);
749 kfree(t_page);
750 }
751
752 static bool null_page_empty(struct nullb_page *page)
753 {
754 int size = MAP_SZ - 2;
755
756 return find_first_bit(page->bitmap, size) == size;
757 }
758
759 static void null_free_sector(struct nullb *nullb, sector_t sector,
760 bool is_cache)
761 {
762 unsigned int sector_bit;
763 u64 idx;
764 struct nullb_page *t_page, *ret;
765 struct radix_tree_root *root;
766
767 root = is_cache ? &nullb->dev->cache : &nullb->dev->data;
768 idx = sector >> PAGE_SECTORS_SHIFT;
769 sector_bit = (sector & SECTOR_MASK);
770
771 t_page = radix_tree_lookup(root, idx);
772 if (t_page) {
773 __clear_bit(sector_bit, t_page->bitmap);
774
775 if (null_page_empty(t_page)) {
776 ret = radix_tree_delete_item(root, idx, t_page);
777 WARN_ON(ret != t_page);
778 null_free_page(ret);
779 if (is_cache)
780 nullb->dev->curr_cache -= PAGE_SIZE;
781 }
782 }
783 }
784
785 static struct nullb_page *null_radix_tree_insert(struct nullb *nullb, u64 idx,
786 struct nullb_page *t_page, bool is_cache)
787 {
788 struct radix_tree_root *root;
789
790 root = is_cache ? &nullb->dev->cache : &nullb->dev->data;
791
792 if (radix_tree_insert(root, idx, t_page)) {
793 null_free_page(t_page);
794 t_page = radix_tree_lookup(root, idx);
795 WARN_ON(!t_page || t_page->page->index != idx);
796 } else if (is_cache)
797 nullb->dev->curr_cache += PAGE_SIZE;
798
799 return t_page;
800 }
801
802 static void null_free_device_storage(struct nullb_device *dev, bool is_cache)
803 {
804 unsigned long pos = 0;
805 int nr_pages;
806 struct nullb_page *ret, *t_pages[FREE_BATCH];
807 struct radix_tree_root *root;
808
809 root = is_cache ? &dev->cache : &dev->data;
810
811 do {
812 int i;
813
814 nr_pages = radix_tree_gang_lookup(root,
815 (void **)t_pages, pos, FREE_BATCH);
816
817 for (i = 0; i < nr_pages; i++) {
818 pos = t_pages[i]->page->index;
819 ret = radix_tree_delete_item(root, pos, t_pages[i]);
820 WARN_ON(ret != t_pages[i]);
821 null_free_page(ret);
822 }
823
824 pos++;
825 } while (nr_pages == FREE_BATCH);
826
827 if (is_cache)
828 dev->curr_cache = 0;
829 }
830
831 static struct nullb_page *__null_lookup_page(struct nullb *nullb,
832 sector_t sector, bool for_write, bool is_cache)
833 {
834 unsigned int sector_bit;
835 u64 idx;
836 struct nullb_page *t_page;
837 struct radix_tree_root *root;
838
839 idx = sector >> PAGE_SECTORS_SHIFT;
840 sector_bit = (sector & SECTOR_MASK);
841
842 root = is_cache ? &nullb->dev->cache : &nullb->dev->data;
843 t_page = radix_tree_lookup(root, idx);
844 WARN_ON(t_page && t_page->page->index != idx);
845
846 if (t_page && (for_write || test_bit(sector_bit, t_page->bitmap)))
847 return t_page;
848
849 return NULL;
850 }
851
852 static struct nullb_page *null_lookup_page(struct nullb *nullb,
853 sector_t sector, bool for_write, bool ignore_cache)
854 {
855 struct nullb_page *page = NULL;
856
857 if (!ignore_cache)
858 page = __null_lookup_page(nullb, sector, for_write, true);
859 if (page)
860 return page;
861 return __null_lookup_page(nullb, sector, for_write, false);
862 }
863
864 static struct nullb_page *null_insert_page(struct nullb *nullb,
865 sector_t sector, bool ignore_cache)
866 {
867 u64 idx;
868 struct nullb_page *t_page;
869
870 t_page = null_lookup_page(nullb, sector, true, ignore_cache);
871 if (t_page)
872 return t_page;
873
874 spin_unlock_irq(&nullb->lock);
875
876 t_page = null_alloc_page(GFP_NOIO);
877 if (!t_page)
878 goto out_lock;
879
880 if (radix_tree_preload(GFP_NOIO))
881 goto out_freepage;
882
883 spin_lock_irq(&nullb->lock);
884 idx = sector >> PAGE_SECTORS_SHIFT;
885 t_page->page->index = idx;
886 t_page = null_radix_tree_insert(nullb, idx, t_page, !ignore_cache);
887 radix_tree_preload_end();
888
889 return t_page;
890 out_freepage:
891 null_free_page(t_page);
892 out_lock:
893 spin_lock_irq(&nullb->lock);
894 return null_lookup_page(nullb, sector, true, ignore_cache);
895 }
896
897 static int null_flush_cache_page(struct nullb *nullb, struct nullb_page *c_page)
898 {
899 int i;
900 unsigned int offset;
901 u64 idx;
902 struct nullb_page *t_page, *ret;
903 void *dst, *src;
904
905 idx = c_page->page->index;
906
907 t_page = null_insert_page(nullb, idx << PAGE_SECTORS_SHIFT, true);
908
909 __clear_bit(NULLB_PAGE_LOCK, c_page->bitmap);
910 if (test_bit(NULLB_PAGE_FREE, c_page->bitmap)) {
911 null_free_page(c_page);
912 if (t_page && null_page_empty(t_page)) {
913 ret = radix_tree_delete_item(&nullb->dev->data,
914 idx, t_page);
915 null_free_page(t_page);
916 }
917 return 0;
918 }
919
920 if (!t_page)
921 return -ENOMEM;
922
923 src = kmap_atomic(c_page->page);
924 dst = kmap_atomic(t_page->page);
925
926 for (i = 0; i < PAGE_SECTORS;
927 i += (nullb->dev->blocksize >> SECTOR_SHIFT)) {
928 if (test_bit(i, c_page->bitmap)) {
929 offset = (i << SECTOR_SHIFT);
930 memcpy(dst + offset, src + offset,
931 nullb->dev->blocksize);
932 __set_bit(i, t_page->bitmap);
933 }
934 }
935
936 kunmap_atomic(dst);
937 kunmap_atomic(src);
938
939 ret = radix_tree_delete_item(&nullb->dev->cache, idx, c_page);
940 null_free_page(ret);
941 nullb->dev->curr_cache -= PAGE_SIZE;
942
943 return 0;
944 }
945
946 static int null_make_cache_space(struct nullb *nullb, unsigned long n)
947 {
948 int i, err, nr_pages;
949 struct nullb_page *c_pages[FREE_BATCH];
950 unsigned long flushed = 0, one_round;
951
952 again:
953 if ((nullb->dev->cache_size * 1024 * 1024) >
954 nullb->dev->curr_cache + n || nullb->dev->curr_cache == 0)
955 return 0;
956
957 nr_pages = radix_tree_gang_lookup(&nullb->dev->cache,
958 (void **)c_pages, nullb->cache_flush_pos, FREE_BATCH);
959 /*
960 * nullb_flush_cache_page could unlock before using the c_pages. To
961 * avoid race, we don't allow page free
962 */
963 for (i = 0; i < nr_pages; i++) {
964 nullb->cache_flush_pos = c_pages[i]->page->index;
965 /*
966 * We found the page which is being flushed to disk by other
967 * threads
968 */
969 if (test_bit(NULLB_PAGE_LOCK, c_pages[i]->bitmap))
970 c_pages[i] = NULL;
971 else
972 __set_bit(NULLB_PAGE_LOCK, c_pages[i]->bitmap);
973 }
974
975 one_round = 0;
976 for (i = 0; i < nr_pages; i++) {
977 if (c_pages[i] == NULL)
978 continue;
979 err = null_flush_cache_page(nullb, c_pages[i]);
980 if (err)
981 return err;
982 one_round++;
983 }
984 flushed += one_round << PAGE_SHIFT;
985
986 if (n > flushed) {
987 if (nr_pages == 0)
988 nullb->cache_flush_pos = 0;
989 if (one_round == 0) {
990 /* give other threads a chance */
991 spin_unlock_irq(&nullb->lock);
992 spin_lock_irq(&nullb->lock);
993 }
994 goto again;
995 }
996 return 0;
997 }
998
999 static int copy_to_nullb(struct nullb *nullb, struct page *source,
1000 unsigned int off, sector_t sector, size_t n, bool is_fua)
1001 {
1002 size_t temp, count = 0;
1003 unsigned int offset;
1004 struct nullb_page *t_page;
1005 void *dst, *src;
1006
1007 while (count < n) {
1008 temp = min_t(size_t, nullb->dev->blocksize, n - count);
1009
1010 if (null_cache_active(nullb) && !is_fua)
1011 null_make_cache_space(nullb, PAGE_SIZE);
1012
1013 offset = (sector & SECTOR_MASK) << SECTOR_SHIFT;
1014 t_page = null_insert_page(nullb, sector,
1015 !null_cache_active(nullb) || is_fua);
1016 if (!t_page)
1017 return -ENOSPC;
1018
1019 src = kmap_atomic(source);
1020 dst = kmap_atomic(t_page->page);
1021 memcpy(dst + offset, src + off + count, temp);
1022 kunmap_atomic(dst);
1023 kunmap_atomic(src);
1024
1025 __set_bit(sector & SECTOR_MASK, t_page->bitmap);
1026
1027 if (is_fua)
1028 null_free_sector(nullb, sector, true);
1029
1030 count += temp;
1031 sector += temp >> SECTOR_SHIFT;
1032 }
1033 return 0;
1034 }
1035
1036 static int copy_from_nullb(struct nullb *nullb, struct page *dest,
1037 unsigned int off, sector_t sector, size_t n)
1038 {
1039 size_t temp, count = 0;
1040 unsigned int offset;
1041 struct nullb_page *t_page;
1042 void *dst, *src;
1043
1044 while (count < n) {
1045 temp = min_t(size_t, nullb->dev->blocksize, n - count);
1046
1047 offset = (sector & SECTOR_MASK) << SECTOR_SHIFT;
1048 t_page = null_lookup_page(nullb, sector, false,
1049 !null_cache_active(nullb));
1050
1051 dst = kmap_atomic(dest);
1052 if (!t_page) {
1053 memset(dst + off + count, 0, temp);
1054 goto next;
1055 }
1056 src = kmap_atomic(t_page->page);
1057 memcpy(dst + off + count, src + offset, temp);
1058 kunmap_atomic(src);
1059 next:
1060 kunmap_atomic(dst);
1061
1062 count += temp;
1063 sector += temp >> SECTOR_SHIFT;
1064 }
1065 return 0;
1066 }
1067
1068 static void null_handle_discard(struct nullb *nullb, sector_t sector, size_t n)
1069 {
1070 size_t temp;
1071
1072 spin_lock_irq(&nullb->lock);
1073 while (n > 0) {
1074 temp = min_t(size_t, n, nullb->dev->blocksize);
1075 null_free_sector(nullb, sector, false);
1076 if (null_cache_active(nullb))
1077 null_free_sector(nullb, sector, true);
1078 sector += temp >> SECTOR_SHIFT;
1079 n -= temp;
1080 }
1081 spin_unlock_irq(&nullb->lock);
1082 }
1083
1084 static int null_handle_flush(struct nullb *nullb)
1085 {
1086 int err;
1087
1088 if (!null_cache_active(nullb))
1089 return 0;
1090
1091 spin_lock_irq(&nullb->lock);
1092 while (true) {
1093 err = null_make_cache_space(nullb,
1094 nullb->dev->cache_size * 1024 * 1024);
1095 if (err || nullb->dev->curr_cache == 0)
1096 break;
1097 }
1098
1099 WARN_ON(!radix_tree_empty(&nullb->dev->cache));
1100 spin_unlock_irq(&nullb->lock);
1101 return err;
1102 }
1103
1104 static int null_transfer(struct nullb *nullb, struct page *page,
1105 unsigned int len, unsigned int off, bool is_write, sector_t sector,
1106 bool is_fua)
1107 {
1108 int err = 0;
1109
1110 if (!is_write) {
1111 err = copy_from_nullb(nullb, page, off, sector, len);
1112 flush_dcache_page(page);
1113 } else {
1114 flush_dcache_page(page);
1115 err = copy_to_nullb(nullb, page, off, sector, len, is_fua);
1116 }
1117
1118 return err;
1119 }
1120
1121 static int null_handle_rq(struct nullb_cmd *cmd)
1122 {
1123 struct request *rq = cmd->rq;
1124 struct nullb *nullb = cmd->nq->dev->nullb;
1125 int err;
1126 unsigned int len;
1127 sector_t sector;
1128 struct req_iterator iter;
1129 struct bio_vec bvec;
1130
1131 sector = blk_rq_pos(rq);
1132
1133 if (req_op(rq) == REQ_OP_DISCARD) {
1134 null_handle_discard(nullb, sector, blk_rq_bytes(rq));
1135 return 0;
1136 }
1137
1138 spin_lock_irq(&nullb->lock);
1139 rq_for_each_segment(bvec, rq, iter) {
1140 len = bvec.bv_len;
1141 err = null_transfer(nullb, bvec.bv_page, len, bvec.bv_offset,
1142 op_is_write(req_op(rq)), sector,
1143 req_op(rq) & REQ_FUA);
1144 if (err) {
1145 spin_unlock_irq(&nullb->lock);
1146 return err;
1147 }
1148 sector += len >> SECTOR_SHIFT;
1149 }
1150 spin_unlock_irq(&nullb->lock);
1151
1152 return 0;
1153 }
1154
1155 static int null_handle_bio(struct nullb_cmd *cmd)
1156 {
1157 struct bio *bio = cmd->bio;
1158 struct nullb *nullb = cmd->nq->dev->nullb;
1159 int err;
1160 unsigned int len;
1161 sector_t sector;
1162 struct bio_vec bvec;
1163 struct bvec_iter iter;
1164
1165 sector = bio->bi_iter.bi_sector;
1166
1167 if (bio_op(bio) == REQ_OP_DISCARD) {
1168 null_handle_discard(nullb, sector,
1169 bio_sectors(bio) << SECTOR_SHIFT);
1170 return 0;
1171 }
1172
1173 spin_lock_irq(&nullb->lock);
1174 bio_for_each_segment(bvec, bio, iter) {
1175 len = bvec.bv_len;
1176 err = null_transfer(nullb, bvec.bv_page, len, bvec.bv_offset,
1177 op_is_write(bio_op(bio)), sector,
1178 bio_op(bio) & REQ_FUA);
1179 if (err) {
1180 spin_unlock_irq(&nullb->lock);
1181 return err;
1182 }
1183 sector += len >> SECTOR_SHIFT;
1184 }
1185 spin_unlock_irq(&nullb->lock);
1186 return 0;
1187 }
1188
1189 static void null_stop_queue(struct nullb *nullb)
1190 {
1191 struct request_queue *q = nullb->q;
1192
1193 if (nullb->dev->queue_mode == NULL_Q_MQ)
1194 blk_mq_stop_hw_queues(q);
1195 else {
1196 spin_lock_irq(q->queue_lock);
1197 blk_stop_queue(q);
1198 spin_unlock_irq(q->queue_lock);
1199 }
1200 }
1201
1202 static void null_restart_queue_async(struct nullb *nullb)
1203 {
1204 struct request_queue *q = nullb->q;
1205 unsigned long flags;
1206
1207 if (nullb->dev->queue_mode == NULL_Q_MQ)
1208 blk_mq_start_stopped_hw_queues(q, true);
1209 else {
1210 spin_lock_irqsave(q->queue_lock, flags);
1211 blk_start_queue_async(q);
1212 spin_unlock_irqrestore(q->queue_lock, flags);
1213 }
1214 }
1215
1216 static blk_status_t null_handle_cmd(struct nullb_cmd *cmd)
1217 {
1218 struct nullb_device *dev = cmd->nq->dev;
1219 struct nullb *nullb = dev->nullb;
1220 int err = 0;
1221
1222 if (test_bit(NULLB_DEV_FL_THROTTLED, &dev->flags)) {
1223 struct request *rq = cmd->rq;
1224
1225 if (!hrtimer_active(&nullb->bw_timer))
1226 hrtimer_restart(&nullb->bw_timer);
1227
1228 if (atomic_long_sub_return(blk_rq_bytes(rq),
1229 &nullb->cur_bytes) < 0) {
1230 null_stop_queue(nullb);
1231 /* race with timer */
1232 if (atomic_long_read(&nullb->cur_bytes) > 0)
1233 null_restart_queue_async(nullb);
1234 if (dev->queue_mode == NULL_Q_RQ) {
1235 struct request_queue *q = nullb->q;
1236
1237 spin_lock_irq(q->queue_lock);
1238 rq->rq_flags |= RQF_DONTPREP;
1239 blk_requeue_request(q, rq);
1240 spin_unlock_irq(q->queue_lock);
1241 return BLK_STS_OK;
1242 } else
1243 /* requeue request */
1244 return BLK_STS_DEV_RESOURCE;
1245 }
1246 }
1247
1248 if (nullb->dev->badblocks.shift != -1) {
1249 int bad_sectors;
1250 sector_t sector, size, first_bad;
1251 bool is_flush = true;
1252
1253 if (dev->queue_mode == NULL_Q_BIO &&
1254 bio_op(cmd->bio) != REQ_OP_FLUSH) {
1255 is_flush = false;
1256 sector = cmd->bio->bi_iter.bi_sector;
1257 size = bio_sectors(cmd->bio);
1258 }
1259 if (dev->queue_mode != NULL_Q_BIO &&
1260 req_op(cmd->rq) != REQ_OP_FLUSH) {
1261 is_flush = false;
1262 sector = blk_rq_pos(cmd->rq);
1263 size = blk_rq_sectors(cmd->rq);
1264 }
1265 if (!is_flush && badblocks_check(&nullb->dev->badblocks, sector,
1266 size, &first_bad, &bad_sectors)) {
1267 cmd->error = BLK_STS_IOERR;
1268 goto out;
1269 }
1270 }
1271
1272 if (dev->memory_backed) {
1273 if (dev->queue_mode == NULL_Q_BIO) {
1274 if (bio_op(cmd->bio) == REQ_OP_FLUSH)
1275 err = null_handle_flush(nullb);
1276 else
1277 err = null_handle_bio(cmd);
1278 } else {
1279 if (req_op(cmd->rq) == REQ_OP_FLUSH)
1280 err = null_handle_flush(nullb);
1281 else
1282 err = null_handle_rq(cmd);
1283 }
1284 }
1285 cmd->error = errno_to_blk_status(err);
1286 out:
1287 /* Complete IO by inline, softirq or timer */
1288 switch (dev->irqmode) {
1289 case NULL_IRQ_SOFTIRQ:
1290 switch (dev->queue_mode) {
1291 case NULL_Q_MQ:
1292 blk_mq_complete_request(cmd->rq);
1293 break;
1294 case NULL_Q_RQ:
1295 blk_complete_request(cmd->rq);
1296 break;
1297 case NULL_Q_BIO:
1298 /*
1299 * XXX: no proper submitting cpu information available.
1300 */
1301 end_cmd(cmd);
1302 break;
1303 }
1304 break;
1305 case NULL_IRQ_NONE:
1306 end_cmd(cmd);
1307 break;
1308 case NULL_IRQ_TIMER:
1309 null_cmd_end_timer(cmd);
1310 break;
1311 }
1312 return BLK_STS_OK;
1313 }
1314
1315 static enum hrtimer_restart nullb_bwtimer_fn(struct hrtimer *timer)
1316 {
1317 struct nullb *nullb = container_of(timer, struct nullb, bw_timer);
1318 ktime_t timer_interval = ktime_set(0, TIMER_INTERVAL);
1319 unsigned int mbps = nullb->dev->mbps;
1320
1321 if (atomic_long_read(&nullb->cur_bytes) == mb_per_tick(mbps))
1322 return HRTIMER_NORESTART;
1323
1324 atomic_long_set(&nullb->cur_bytes, mb_per_tick(mbps));
1325 null_restart_queue_async(nullb);
1326
1327 hrtimer_forward_now(&nullb->bw_timer, timer_interval);
1328
1329 return HRTIMER_RESTART;
1330 }
1331
1332 static void nullb_setup_bwtimer(struct nullb *nullb)
1333 {
1334 ktime_t timer_interval = ktime_set(0, TIMER_INTERVAL);
1335
1336 hrtimer_init(&nullb->bw_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
1337 nullb->bw_timer.function = nullb_bwtimer_fn;
1338 atomic_long_set(&nullb->cur_bytes, mb_per_tick(nullb->dev->mbps));
1339 hrtimer_start(&nullb->bw_timer, timer_interval, HRTIMER_MODE_REL);
1340 }
1341
1342 static struct nullb_queue *nullb_to_queue(struct nullb *nullb)
1343 {
1344 int index = 0;
1345
1346 if (nullb->nr_queues != 1)
1347 index = raw_smp_processor_id() / ((nr_cpu_ids + nullb->nr_queues - 1) / nullb->nr_queues);
1348
1349 return &nullb->queues[index];
1350 }
1351
1352 static blk_qc_t null_queue_bio(struct request_queue *q, struct bio *bio)
1353 {
1354 struct nullb *nullb = q->queuedata;
1355 struct nullb_queue *nq = nullb_to_queue(nullb);
1356 struct nullb_cmd *cmd;
1357
1358 cmd = alloc_cmd(nq, 1);
1359 cmd->bio = bio;
1360
1361 null_handle_cmd(cmd);
1362 return BLK_QC_T_NONE;
1363 }
1364
1365 static enum blk_eh_timer_return null_rq_timed_out_fn(struct request *rq)
1366 {
1367 pr_info("null: rq %p timed out\n", rq);
1368 __blk_complete_request(rq);
1369 return BLK_EH_DONE;
1370 }
1371
1372 static int null_rq_prep_fn(struct request_queue *q, struct request *req)
1373 {
1374 struct nullb *nullb = q->queuedata;
1375 struct nullb_queue *nq = nullb_to_queue(nullb);
1376 struct nullb_cmd *cmd;
1377
1378 cmd = alloc_cmd(nq, 0);
1379 if (cmd) {
1380 cmd->rq = req;
1381 req->special = cmd;
1382 return BLKPREP_OK;
1383 }
1384 blk_stop_queue(q);
1385
1386 return BLKPREP_DEFER;
1387 }
1388
1389 static bool should_timeout_request(struct request *rq)
1390 {
1391 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
1392 if (g_timeout_str[0])
1393 return should_fail(&null_timeout_attr, 1);
1394 #endif
1395 return false;
1396 }
1397
1398 static bool should_requeue_request(struct request *rq)
1399 {
1400 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
1401 if (g_requeue_str[0])
1402 return should_fail(&null_requeue_attr, 1);
1403 #endif
1404 return false;
1405 }
1406
1407 static void null_request_fn(struct request_queue *q)
1408 {
1409 struct request *rq;
1410
1411 while ((rq = blk_fetch_request(q)) != NULL) {
1412 struct nullb_cmd *cmd = rq->special;
1413
1414 /* just ignore the request */
1415 if (should_timeout_request(rq))
1416 continue;
1417 if (should_requeue_request(rq)) {
1418 blk_requeue_request(q, rq);
1419 continue;
1420 }
1421
1422 spin_unlock_irq(q->queue_lock);
1423 null_handle_cmd(cmd);
1424 spin_lock_irq(q->queue_lock);
1425 }
1426 }
1427
1428 static enum blk_eh_timer_return null_timeout_rq(struct request *rq, bool res)
1429 {
1430 pr_info("null: rq %p timed out\n", rq);
1431 blk_mq_complete_request(rq);
1432 return BLK_EH_DONE;
1433 }
1434
1435 static blk_status_t null_queue_rq(struct blk_mq_hw_ctx *hctx,
1436 const struct blk_mq_queue_data *bd)
1437 {
1438 struct nullb_cmd *cmd = blk_mq_rq_to_pdu(bd->rq);
1439 struct nullb_queue *nq = hctx->driver_data;
1440
1441 might_sleep_if(hctx->flags & BLK_MQ_F_BLOCKING);
1442
1443 if (nq->dev->irqmode == NULL_IRQ_TIMER) {
1444 hrtimer_init(&cmd->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
1445 cmd->timer.function = null_cmd_timer_expired;
1446 }
1447 cmd->rq = bd->rq;
1448 cmd->nq = nq;
1449
1450 blk_mq_start_request(bd->rq);
1451
1452 if (should_requeue_request(bd->rq)) {
1453 /*
1454 * Alternate between hitting the core BUSY path, and the
1455 * driver driven requeue path
1456 */
1457 nq->requeue_selection++;
1458 if (nq->requeue_selection & 1)
1459 return BLK_STS_RESOURCE;
1460 else {
1461 blk_mq_requeue_request(bd->rq, true);
1462 return BLK_STS_OK;
1463 }
1464 }
1465 if (should_timeout_request(bd->rq))
1466 return BLK_STS_OK;
1467
1468 return null_handle_cmd(cmd);
1469 }
1470
1471 static const struct blk_mq_ops null_mq_ops = {
1472 .queue_rq = null_queue_rq,
1473 .complete = null_softirq_done_fn,
1474 .timeout = null_timeout_rq,
1475 };
1476
1477 static void cleanup_queue(struct nullb_queue *nq)
1478 {
1479 kfree(nq->tag_map);
1480 kfree(nq->cmds);
1481 }
1482
1483 static void cleanup_queues(struct nullb *nullb)
1484 {
1485 int i;
1486
1487 for (i = 0; i < nullb->nr_queues; i++)
1488 cleanup_queue(&nullb->queues[i]);
1489
1490 kfree(nullb->queues);
1491 }
1492
1493 static void null_del_dev(struct nullb *nullb)
1494 {
1495 struct nullb_device *dev = nullb->dev;
1496
1497 ida_simple_remove(&nullb_indexes, nullb->index);
1498
1499 list_del_init(&nullb->list);
1500
1501 del_gendisk(nullb->disk);
1502
1503 if (test_bit(NULLB_DEV_FL_THROTTLED, &nullb->dev->flags)) {
1504 hrtimer_cancel(&nullb->bw_timer);
1505 atomic_long_set(&nullb->cur_bytes, LONG_MAX);
1506 null_restart_queue_async(nullb);
1507 }
1508
1509 blk_cleanup_queue(nullb->q);
1510 if (dev->queue_mode == NULL_Q_MQ &&
1511 nullb->tag_set == &nullb->__tag_set)
1512 blk_mq_free_tag_set(nullb->tag_set);
1513 put_disk(nullb->disk);
1514 cleanup_queues(nullb);
1515 if (null_cache_active(nullb))
1516 null_free_device_storage(nullb->dev, true);
1517 kfree(nullb);
1518 dev->nullb = NULL;
1519 }
1520
1521 static void null_config_discard(struct nullb *nullb)
1522 {
1523 if (nullb->dev->discard == false)
1524 return;
1525 nullb->q->limits.discard_granularity = nullb->dev->blocksize;
1526 nullb->q->limits.discard_alignment = nullb->dev->blocksize;
1527 blk_queue_max_discard_sectors(nullb->q, UINT_MAX >> 9);
1528 blk_queue_flag_set(QUEUE_FLAG_DISCARD, nullb->q);
1529 }
1530
1531 static int null_open(struct block_device *bdev, fmode_t mode)
1532 {
1533 return 0;
1534 }
1535
1536 static void null_release(struct gendisk *disk, fmode_t mode)
1537 {
1538 }
1539
1540 static const struct block_device_operations null_fops = {
1541 .owner = THIS_MODULE,
1542 .open = null_open,
1543 .release = null_release,
1544 };
1545
1546 static void null_init_queue(struct nullb *nullb, struct nullb_queue *nq)
1547 {
1548 BUG_ON(!nullb);
1549 BUG_ON(!nq);
1550
1551 init_waitqueue_head(&nq->wait);
1552 nq->queue_depth = nullb->queue_depth;
1553 nq->dev = nullb->dev;
1554 }
1555
1556 static void null_init_queues(struct nullb *nullb)
1557 {
1558 struct request_queue *q = nullb->q;
1559 struct blk_mq_hw_ctx *hctx;
1560 struct nullb_queue *nq;
1561 int i;
1562
1563 queue_for_each_hw_ctx(q, hctx, i) {
1564 if (!hctx->nr_ctx || !hctx->tags)
1565 continue;
1566 nq = &nullb->queues[i];
1567 hctx->driver_data = nq;
1568 null_init_queue(nullb, nq);
1569 nullb->nr_queues++;
1570 }
1571 }
1572
1573 static int setup_commands(struct nullb_queue *nq)
1574 {
1575 struct nullb_cmd *cmd;
1576 int i, tag_size;
1577
1578 nq->cmds = kcalloc(nq->queue_depth, sizeof(*cmd), GFP_KERNEL);
1579 if (!nq->cmds)
1580 return -ENOMEM;
1581
1582 tag_size = ALIGN(nq->queue_depth, BITS_PER_LONG) / BITS_PER_LONG;
1583 nq->tag_map = kcalloc(tag_size, sizeof(unsigned long), GFP_KERNEL);
1584 if (!nq->tag_map) {
1585 kfree(nq->cmds);
1586 return -ENOMEM;
1587 }
1588
1589 for (i = 0; i < nq->queue_depth; i++) {
1590 cmd = &nq->cmds[i];
1591 INIT_LIST_HEAD(&cmd->list);
1592 cmd->ll_list.next = NULL;
1593 cmd->tag = -1U;
1594 }
1595
1596 return 0;
1597 }
1598
1599 static int setup_queues(struct nullb *nullb)
1600 {
1601 nullb->queues = kcalloc(nullb->dev->submit_queues,
1602 sizeof(struct nullb_queue),
1603 GFP_KERNEL);
1604 if (!nullb->queues)
1605 return -ENOMEM;
1606
1607 nullb->nr_queues = 0;
1608 nullb->queue_depth = nullb->dev->hw_queue_depth;
1609
1610 return 0;
1611 }
1612
1613 static int init_driver_queues(struct nullb *nullb)
1614 {
1615 struct nullb_queue *nq;
1616 int i, ret = 0;
1617
1618 for (i = 0; i < nullb->dev->submit_queues; i++) {
1619 nq = &nullb->queues[i];
1620
1621 null_init_queue(nullb, nq);
1622
1623 ret = setup_commands(nq);
1624 if (ret)
1625 return ret;
1626 nullb->nr_queues++;
1627 }
1628 return 0;
1629 }
1630
1631 static int null_gendisk_register(struct nullb *nullb)
1632 {
1633 struct gendisk *disk;
1634 sector_t size;
1635
1636 disk = nullb->disk = alloc_disk_node(1, nullb->dev->home_node);
1637 if (!disk)
1638 return -ENOMEM;
1639 size = (sector_t)nullb->dev->size * 1024 * 1024ULL;
1640 set_capacity(disk, size >> 9);
1641
1642 disk->flags |= GENHD_FL_EXT_DEVT | GENHD_FL_SUPPRESS_PARTITION_INFO;
1643 disk->major = null_major;
1644 disk->first_minor = nullb->index;
1645 disk->fops = &null_fops;
1646 disk->private_data = nullb;
1647 disk->queue = nullb->q;
1648 strncpy(disk->disk_name, nullb->disk_name, DISK_NAME_LEN);
1649
1650 add_disk(disk);
1651 return 0;
1652 }
1653
1654 static int null_init_tag_set(struct nullb *nullb, struct blk_mq_tag_set *set)
1655 {
1656 set->ops = &null_mq_ops;
1657 set->nr_hw_queues = nullb ? nullb->dev->submit_queues :
1658 g_submit_queues;
1659 set->queue_depth = nullb ? nullb->dev->hw_queue_depth :
1660 g_hw_queue_depth;
1661 set->numa_node = nullb ? nullb->dev->home_node : g_home_node;
1662 set->cmd_size = sizeof(struct nullb_cmd);
1663 set->flags = BLK_MQ_F_SHOULD_MERGE;
1664 if (g_no_sched)
1665 set->flags |= BLK_MQ_F_NO_SCHED;
1666 set->driver_data = NULL;
1667
1668 if ((nullb && nullb->dev->blocking) || g_blocking)
1669 set->flags |= BLK_MQ_F_BLOCKING;
1670
1671 return blk_mq_alloc_tag_set(set);
1672 }
1673
1674 static void null_validate_conf(struct nullb_device *dev)
1675 {
1676 dev->blocksize = round_down(dev->blocksize, 512);
1677 dev->blocksize = clamp_t(unsigned int, dev->blocksize, 512, 4096);
1678
1679 if (dev->queue_mode == NULL_Q_MQ && dev->use_per_node_hctx) {
1680 if (dev->submit_queues != nr_online_nodes)
1681 dev->submit_queues = nr_online_nodes;
1682 } else if (dev->submit_queues > nr_cpu_ids)
1683 dev->submit_queues = nr_cpu_ids;
1684 else if (dev->submit_queues == 0)
1685 dev->submit_queues = 1;
1686
1687 dev->queue_mode = min_t(unsigned int, dev->queue_mode, NULL_Q_MQ);
1688 dev->irqmode = min_t(unsigned int, dev->irqmode, NULL_IRQ_TIMER);
1689
1690 /* Do memory allocation, so set blocking */
1691 if (dev->memory_backed)
1692 dev->blocking = true;
1693 else /* cache is meaningless */
1694 dev->cache_size = 0;
1695 dev->cache_size = min_t(unsigned long, ULONG_MAX / 1024 / 1024,
1696 dev->cache_size);
1697 dev->mbps = min_t(unsigned int, 1024 * 40, dev->mbps);
1698 /* can not stop a queue */
1699 if (dev->queue_mode == NULL_Q_BIO)
1700 dev->mbps = 0;
1701 }
1702
1703 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
1704 static bool __null_setup_fault(struct fault_attr *attr, char *str)
1705 {
1706 if (!str[0])
1707 return true;
1708
1709 if (!setup_fault_attr(attr, str))
1710 return false;
1711
1712 attr->verbose = 0;
1713 return true;
1714 }
1715 #endif
1716
1717 static bool null_setup_fault(void)
1718 {
1719 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
1720 if (!__null_setup_fault(&null_timeout_attr, g_timeout_str))
1721 return false;
1722 if (!__null_setup_fault(&null_requeue_attr, g_requeue_str))
1723 return false;
1724 #endif
1725 return true;
1726 }
1727
1728 static int null_add_dev(struct nullb_device *dev)
1729 {
1730 struct nullb *nullb;
1731 int rv;
1732
1733 null_validate_conf(dev);
1734
1735 nullb = kzalloc_node(sizeof(*nullb), GFP_KERNEL, dev->home_node);
1736 if (!nullb) {
1737 rv = -ENOMEM;
1738 goto out;
1739 }
1740 nullb->dev = dev;
1741 dev->nullb = nullb;
1742
1743 spin_lock_init(&nullb->lock);
1744
1745 rv = setup_queues(nullb);
1746 if (rv)
1747 goto out_free_nullb;
1748
1749 if (dev->queue_mode == NULL_Q_MQ) {
1750 if (shared_tags) {
1751 nullb->tag_set = &tag_set;
1752 rv = 0;
1753 } else {
1754 nullb->tag_set = &nullb->__tag_set;
1755 rv = null_init_tag_set(nullb, nullb->tag_set);
1756 }
1757
1758 if (rv)
1759 goto out_cleanup_queues;
1760
1761 if (!null_setup_fault())
1762 goto out_cleanup_queues;
1763
1764 nullb->tag_set->timeout = 5 * HZ;
1765 nullb->q = blk_mq_init_queue(nullb->tag_set);
1766 if (IS_ERR(nullb->q)) {
1767 rv = -ENOMEM;
1768 goto out_cleanup_tags;
1769 }
1770 null_init_queues(nullb);
1771 } else if (dev->queue_mode == NULL_Q_BIO) {
1772 nullb->q = blk_alloc_queue_node(GFP_KERNEL, dev->home_node,
1773 NULL);
1774 if (!nullb->q) {
1775 rv = -ENOMEM;
1776 goto out_cleanup_queues;
1777 }
1778 blk_queue_make_request(nullb->q, null_queue_bio);
1779 rv = init_driver_queues(nullb);
1780 if (rv)
1781 goto out_cleanup_blk_queue;
1782 } else {
1783 nullb->q = blk_init_queue_node(null_request_fn, &nullb->lock,
1784 dev->home_node);
1785 if (!nullb->q) {
1786 rv = -ENOMEM;
1787 goto out_cleanup_queues;
1788 }
1789
1790 if (!null_setup_fault())
1791 goto out_cleanup_blk_queue;
1792
1793 blk_queue_prep_rq(nullb->q, null_rq_prep_fn);
1794 blk_queue_softirq_done(nullb->q, null_softirq_done_fn);
1795 blk_queue_rq_timed_out(nullb->q, null_rq_timed_out_fn);
1796 nullb->q->rq_timeout = 5 * HZ;
1797 rv = init_driver_queues(nullb);
1798 if (rv)
1799 goto out_cleanup_blk_queue;
1800 }
1801
1802 if (dev->mbps) {
1803 set_bit(NULLB_DEV_FL_THROTTLED, &dev->flags);
1804 nullb_setup_bwtimer(nullb);
1805 }
1806
1807 if (dev->cache_size > 0) {
1808 set_bit(NULLB_DEV_FL_CACHE, &nullb->dev->flags);
1809 blk_queue_write_cache(nullb->q, true, true);
1810 blk_queue_flush_queueable(nullb->q, true);
1811 }
1812
1813 nullb->q->queuedata = nullb;
1814 blk_queue_flag_set(QUEUE_FLAG_NONROT, nullb->q);
1815 blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, nullb->q);
1816
1817 mutex_lock(&lock);
1818 nullb->index = ida_simple_get(&nullb_indexes, 0, 0, GFP_KERNEL);
1819 dev->index = nullb->index;
1820 mutex_unlock(&lock);
1821
1822 blk_queue_logical_block_size(nullb->q, dev->blocksize);
1823 blk_queue_physical_block_size(nullb->q, dev->blocksize);
1824
1825 null_config_discard(nullb);
1826
1827 sprintf(nullb->disk_name, "nullb%d", nullb->index);
1828
1829 rv = null_gendisk_register(nullb);
1830 if (rv)
1831 goto out_cleanup_blk_queue;
1832
1833 mutex_lock(&lock);
1834 list_add_tail(&nullb->list, &nullb_list);
1835 mutex_unlock(&lock);
1836
1837 return 0;
1838 out_cleanup_blk_queue:
1839 blk_cleanup_queue(nullb->q);
1840 out_cleanup_tags:
1841 if (dev->queue_mode == NULL_Q_MQ && nullb->tag_set == &nullb->__tag_set)
1842 blk_mq_free_tag_set(nullb->tag_set);
1843 out_cleanup_queues:
1844 cleanup_queues(nullb);
1845 out_free_nullb:
1846 kfree(nullb);
1847 out:
1848 return rv;
1849 }
1850
1851 static int __init null_init(void)
1852 {
1853 int ret = 0;
1854 unsigned int i;
1855 struct nullb *nullb;
1856 struct nullb_device *dev;
1857
1858 if (g_bs > PAGE_SIZE) {
1859 pr_warn("null_blk: invalid block size\n");
1860 pr_warn("null_blk: defaults block size to %lu\n", PAGE_SIZE);
1861 g_bs = PAGE_SIZE;
1862 }
1863
1864 if (g_queue_mode == NULL_Q_MQ && g_use_per_node_hctx) {
1865 if (g_submit_queues != nr_online_nodes) {
1866 pr_warn("null_blk: submit_queues param is set to %u.\n",
1867 nr_online_nodes);
1868 g_submit_queues = nr_online_nodes;
1869 }
1870 } else if (g_submit_queues > nr_cpu_ids)
1871 g_submit_queues = nr_cpu_ids;
1872 else if (g_submit_queues <= 0)
1873 g_submit_queues = 1;
1874
1875 if (g_queue_mode == NULL_Q_MQ && shared_tags) {
1876 ret = null_init_tag_set(NULL, &tag_set);
1877 if (ret)
1878 return ret;
1879 }
1880
1881 config_group_init(&nullb_subsys.su_group);
1882 mutex_init(&nullb_subsys.su_mutex);
1883
1884 ret = configfs_register_subsystem(&nullb_subsys);
1885 if (ret)
1886 goto err_tagset;
1887
1888 mutex_init(&lock);
1889
1890 null_major = register_blkdev(0, "nullb");
1891 if (null_major < 0) {
1892 ret = null_major;
1893 goto err_conf;
1894 }
1895
1896 for (i = 0; i < nr_devices; i++) {
1897 dev = null_alloc_dev();
1898 if (!dev) {
1899 ret = -ENOMEM;
1900 goto err_dev;
1901 }
1902 ret = null_add_dev(dev);
1903 if (ret) {
1904 null_free_dev(dev);
1905 goto err_dev;
1906 }
1907 }
1908
1909 pr_info("null: module loaded\n");
1910 return 0;
1911
1912 err_dev:
1913 while (!list_empty(&nullb_list)) {
1914 nullb = list_entry(nullb_list.next, struct nullb, list);
1915 dev = nullb->dev;
1916 null_del_dev(nullb);
1917 null_free_dev(dev);
1918 }
1919 unregister_blkdev(null_major, "nullb");
1920 err_conf:
1921 configfs_unregister_subsystem(&nullb_subsys);
1922 err_tagset:
1923 if (g_queue_mode == NULL_Q_MQ && shared_tags)
1924 blk_mq_free_tag_set(&tag_set);
1925 return ret;
1926 }
1927
1928 static void __exit null_exit(void)
1929 {
1930 struct nullb *nullb;
1931
1932 configfs_unregister_subsystem(&nullb_subsys);
1933
1934 unregister_blkdev(null_major, "nullb");
1935
1936 mutex_lock(&lock);
1937 while (!list_empty(&nullb_list)) {
1938 struct nullb_device *dev;
1939
1940 nullb = list_entry(nullb_list.next, struct nullb, list);
1941 dev = nullb->dev;
1942 null_del_dev(nullb);
1943 null_free_dev(dev);
1944 }
1945 mutex_unlock(&lock);
1946
1947 if (g_queue_mode == NULL_Q_MQ && shared_tags)
1948 blk_mq_free_tag_set(&tag_set);
1949 }
1950
1951 module_init(null_init);
1952 module_exit(null_exit);
1953
1954 MODULE_AUTHOR("Jens Axboe <axboe@kernel.dk>");
1955 MODULE_LICENSE("GPL");
Linux with added FPC-III support