1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Add configfs and memory store: Kyungchan Koh <kkc6196@fb.com> and
4 * Shaohua Li <shli@fb.com>
5 */
6 #include <linux/module.h>
7
8 #include <linux/moduleparam.h>
9 #include <linux/sched.h>
10 #include <linux/fs.h>
11 #include <linux/init.h>
12 #include "null_blk.h"
13
14 #define PAGE_SECTORS_SHIFT (PAGE_SHIFT - SECTOR_SHIFT)
15 #define PAGE_SECTORS (1 << PAGE_SECTORS_SHIFT)
16 #define SECTOR_MASK (PAGE_SECTORS - 1)
17
18 #define FREE_BATCH 16
19
20 #define TICKS_PER_SEC 50ULL
21 #define TIMER_INTERVAL (NSEC_PER_SEC / TICKS_PER_SEC)
22
23 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
24 static DECLARE_FAULT_ATTR(null_timeout_attr);
25 static DECLARE_FAULT_ATTR(null_requeue_attr);
26 #endif
27
mb_per_tick(int mbps)28 static inline u64 mb_per_tick(int mbps)
29 {
30 return (1 << 20) / TICKS_PER_SEC * ((u64) mbps);
31 }
32
33 /*
34 * Status flags for nullb_device.
35 *
36 * CONFIGURED: Device has been configured and turned on. Cannot reconfigure.
37 * UP: Device is currently on and visible in userspace.
38 * THROTTLED: Device is being throttled.
39 * CACHE: Device is using a write-back cache.
40 */
41 enum nullb_device_flags {
42 NULLB_DEV_FL_CONFIGURED = 0,
43 NULLB_DEV_FL_UP = 1,
44 NULLB_DEV_FL_THROTTLED = 2,
45 NULLB_DEV_FL_CACHE = 3,
46 };
47
48 #define MAP_SZ ((PAGE_SIZE >> SECTOR_SHIFT) + 2)
49 /*
50 * nullb_page is a page in memory for nullb devices.
51 *
52 * @page: The page holding the data.
53 * @bitmap: The bitmap represents which sector in the page has data.
54 * Each bit represents one block size. For example, sector 8
55 * will use the 7th bit
56 * The highest 2 bits of bitmap are for special purpose. LOCK means the cache
57 * page is being flushing to storage. FREE means the cache page is freed and
58 * should be skipped from flushing to storage. Please see
59 * null_make_cache_space
60 */
61 struct nullb_page {
62 struct page *page;
63 DECLARE_BITMAP(bitmap, MAP_SZ);
64 };
65 #define NULLB_PAGE_LOCK (MAP_SZ - 1)
66 #define NULLB_PAGE_FREE (MAP_SZ - 2)
67
68 static LIST_HEAD(nullb_list);
69 static struct mutex lock;
70 static int null_major;
71 static DEFINE_IDA(nullb_indexes);
72 static struct blk_mq_tag_set tag_set;
73
74 enum {
75 NULL_IRQ_NONE = 0,
76 NULL_IRQ_SOFTIRQ = 1,
77 NULL_IRQ_TIMER = 2,
78 };
79
80 enum {
81 NULL_Q_BIO = 0,
82 NULL_Q_RQ = 1,
83 NULL_Q_MQ = 2,
84 };
85
86 static int g_no_sched;
87 module_param_named(no_sched, g_no_sched, int, 0444);
88 MODULE_PARM_DESC(no_sched, "No io scheduler");
89
90 static int g_submit_queues = 1;
91 module_param_named(submit_queues, g_submit_queues, int, 0444);
92 MODULE_PARM_DESC(submit_queues, "Number of submission queues");
93
94 static int g_home_node = NUMA_NO_NODE;
95 module_param_named(home_node, g_home_node, int, 0444);
96 MODULE_PARM_DESC(home_node, "Home node for the device");
97
98 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
99 static char g_timeout_str[80];
100 module_param_string(timeout, g_timeout_str, sizeof(g_timeout_str), 0444);
101
102 static char g_requeue_str[80];
103 module_param_string(requeue, g_requeue_str, sizeof(g_requeue_str), 0444);
104 #endif
105
106 static int g_queue_mode = NULL_Q_MQ;
107
null_param_store_val(const char * str,int * val,int min,int max)108 static int null_param_store_val(const char *str, int *val, int min, int max)
109 {
110 int ret, new_val;
111
112 ret = kstrtoint(str, 10, &new_val);
113 if (ret)
114 return -EINVAL;
115
116 if (new_val < min || new_val > max)
117 return -EINVAL;
118
119 *val = new_val;
120 return 0;
121 }
122
null_set_queue_mode(const char * str,const struct kernel_param * kp)123 static int null_set_queue_mode(const char *str, const struct kernel_param *kp)
124 {
125 return null_param_store_val(str, &g_queue_mode, NULL_Q_BIO, NULL_Q_MQ);
126 }
127
128 static const struct kernel_param_ops null_queue_mode_param_ops = {
129 .set = null_set_queue_mode,
130 .get = param_get_int,
131 };
132
133 device_param_cb(queue_mode, &null_queue_mode_param_ops, &g_queue_mode, 0444);
134 MODULE_PARM_DESC(queue_mode, "Block interface to use (0=bio,1=rq,2=multiqueue)");
135
136 static int g_gb = 250;
137 module_param_named(gb, g_gb, int, 0444);
138 MODULE_PARM_DESC(gb, "Size in GB");
139
140 static int g_bs = 512;
141 module_param_named(bs, g_bs, int, 0444);
142 MODULE_PARM_DESC(bs, "Block size (in bytes)");
143
144 static unsigned int nr_devices = 1;
145 module_param(nr_devices, uint, 0444);
146 MODULE_PARM_DESC(nr_devices, "Number of devices to register");
147
148 static bool g_blocking;
149 module_param_named(blocking, g_blocking, bool, 0444);
150 MODULE_PARM_DESC(blocking, "Register as a blocking blk-mq driver device");
151
152 static bool shared_tags;
153 module_param(shared_tags, bool, 0444);
154 MODULE_PARM_DESC(shared_tags, "Share tag set between devices for blk-mq");
155
156 static int g_irqmode = NULL_IRQ_SOFTIRQ;
157
null_set_irqmode(const char * str,const struct kernel_param * kp)158 static int null_set_irqmode(const char *str, const struct kernel_param *kp)
159 {
160 return null_param_store_val(str, &g_irqmode, NULL_IRQ_NONE,
161 NULL_IRQ_TIMER);
162 }
163
164 static const struct kernel_param_ops null_irqmode_param_ops = {
165 .set = null_set_irqmode,
166 .get = param_get_int,
167 };
168
169 device_param_cb(irqmode, &null_irqmode_param_ops, &g_irqmode, 0444);
170 MODULE_PARM_DESC(irqmode, "IRQ completion handler. 0-none, 1-softirq, 2-timer");
171
172 static unsigned long g_completion_nsec = 10000;
173 module_param_named(completion_nsec, g_completion_nsec, ulong, 0444);
174 MODULE_PARM_DESC(completion_nsec, "Time in ns to complete a request in hardware. Default: 10,000ns");
175
176 static int g_hw_queue_depth = 64;
177 module_param_named(hw_queue_depth, g_hw_queue_depth, int, 0444);
178 MODULE_PARM_DESC(hw_queue_depth, "Queue depth for each hardware queue. Default: 64");
179
180 static bool g_use_per_node_hctx;
181 module_param_named(use_per_node_hctx, g_use_per_node_hctx, bool, 0444);
182 MODULE_PARM_DESC(use_per_node_hctx, "Use per-node allocation for hardware context queues. Default: false");
183
184 static bool g_zoned;
185 module_param_named(zoned, g_zoned, bool, S_IRUGO);
186 MODULE_PARM_DESC(zoned, "Make device as a host-managed zoned block device. Default: false");
187
188 static unsigned long g_zone_size = 256;
189 module_param_named(zone_size, g_zone_size, ulong, S_IRUGO);
190 MODULE_PARM_DESC(zone_size, "Zone size in MB when block device is zoned. Must be power-of-two: Default: 256");
191
192 static unsigned int g_zone_nr_conv;
193 module_param_named(zone_nr_conv, g_zone_nr_conv, uint, 0444);
194 MODULE_PARM_DESC(zone_nr_conv, "Number of conventional zones when block device is zoned. Default: 0");
195
196 static struct nullb_device *null_alloc_dev(void);
197 static void null_free_dev(struct nullb_device *dev);
198 static void null_del_dev(struct nullb *nullb);
199 static int null_add_dev(struct nullb_device *dev);
200 static void null_free_device_storage(struct nullb_device *dev, bool is_cache);
201
to_nullb_device(struct config_item * item)202 static inline struct nullb_device *to_nullb_device(struct config_item *item)
203 {
204 return item ? container_of(item, struct nullb_device, item) : NULL;
205 }
206
nullb_device_uint_attr_show(unsigned int val,char * page)207 static inline ssize_t nullb_device_uint_attr_show(unsigned int val, char *page)
208 {
209 return snprintf(page, PAGE_SIZE, "%u\n", val);
210 }
211
nullb_device_ulong_attr_show(unsigned long val,char * page)212 static inline ssize_t nullb_device_ulong_attr_show(unsigned long val,
213 char *page)
214 {
215 return snprintf(page, PAGE_SIZE, "%lu\n", val);
216 }
217
nullb_device_bool_attr_show(bool val,char * page)218 static inline ssize_t nullb_device_bool_attr_show(bool val, char *page)
219 {
220 return snprintf(page, PAGE_SIZE, "%u\n", val);
221 }
222
nullb_device_uint_attr_store(unsigned int * val,const char * page,size_t count)223 static ssize_t nullb_device_uint_attr_store(unsigned int *val,
224 const char *page, size_t count)
225 {
226 unsigned int tmp;
227 int result;
228
229 result = kstrtouint(page, 0, &tmp);
230 if (result)
231 return result;
232
233 *val = tmp;
234 return count;
235 }
236
nullb_device_ulong_attr_store(unsigned long * val,const char * page,size_t count)237 static ssize_t nullb_device_ulong_attr_store(unsigned long *val,
238 const char *page, size_t count)
239 {
240 int result;
241 unsigned long tmp;
242
243 result = kstrtoul(page, 0, &tmp);
244 if (result)
245 return result;
246
247 *val = tmp;
248 return count;
249 }
250
nullb_device_bool_attr_store(bool * val,const char * page,size_t count)251 static ssize_t nullb_device_bool_attr_store(bool *val, const char *page,
252 size_t count)
253 {
254 bool tmp;
255 int result;
256
257 result = kstrtobool(page, &tmp);
258 if (result)
259 return result;
260
261 *val = tmp;
262 return count;
263 }
264
265 /* The following macro should only be used with TYPE = {uint, ulong, bool}. */
266 #define NULLB_DEVICE_ATTR(NAME, TYPE) \
267 static ssize_t \
268 nullb_device_##NAME##_show(struct config_item *item, char *page) \
269 { \
270 return nullb_device_##TYPE##_attr_show( \
271 to_nullb_device(item)->NAME, page); \
272 } \
273 static ssize_t \
274 nullb_device_##NAME##_store(struct config_item *item, const char *page, \
275 size_t count) \
276 { \
277 if (test_bit(NULLB_DEV_FL_CONFIGURED, &to_nullb_device(item)->flags)) \
278 return -EBUSY; \
279 return nullb_device_##TYPE##_attr_store( \
280 &to_nullb_device(item)->NAME, page, count); \
281 } \
282 CONFIGFS_ATTR(nullb_device_, NAME);
283
284 NULLB_DEVICE_ATTR(size, ulong);
285 NULLB_DEVICE_ATTR(completion_nsec, ulong);
286 NULLB_DEVICE_ATTR(submit_queues, uint);
287 NULLB_DEVICE_ATTR(home_node, uint);
288 NULLB_DEVICE_ATTR(queue_mode, uint);
289 NULLB_DEVICE_ATTR(blocksize, uint);
290 NULLB_DEVICE_ATTR(irqmode, uint);
291 NULLB_DEVICE_ATTR(hw_queue_depth, uint);
292 NULLB_DEVICE_ATTR(index, uint);
293 NULLB_DEVICE_ATTR(blocking, bool);
294 NULLB_DEVICE_ATTR(use_per_node_hctx, bool);
295 NULLB_DEVICE_ATTR(memory_backed, bool);
296 NULLB_DEVICE_ATTR(discard, bool);
297 NULLB_DEVICE_ATTR(mbps, uint);
298 NULLB_DEVICE_ATTR(cache_size, ulong);
299 NULLB_DEVICE_ATTR(zoned, bool);
300 NULLB_DEVICE_ATTR(zone_size, ulong);
301 NULLB_DEVICE_ATTR(zone_nr_conv, uint);
302
nullb_device_power_show(struct config_item * item,char * page)303 static ssize_t nullb_device_power_show(struct config_item *item, char *page)
304 {
305 return nullb_device_bool_attr_show(to_nullb_device(item)->power, page);
306 }
307
nullb_device_power_store(struct config_item * item,const char * page,size_t count)308 static ssize_t nullb_device_power_store(struct config_item *item,
309 const char *page, size_t count)
310 {
311 struct nullb_device *dev = to_nullb_device(item);
312 bool newp = false;
313 ssize_t ret;
314
315 ret = nullb_device_bool_attr_store(&newp, page, count);
316 if (ret < 0)
317 return ret;
318
319 if (!dev->power && newp) {
320 if (test_and_set_bit(NULLB_DEV_FL_UP, &dev->flags))
321 return count;
322 if (null_add_dev(dev)) {
323 clear_bit(NULLB_DEV_FL_UP, &dev->flags);
324 return -ENOMEM;
325 }
326
327 set_bit(NULLB_DEV_FL_CONFIGURED, &dev->flags);
328 dev->power = newp;
329 } else if (dev->power && !newp) {
330 if (test_and_clear_bit(NULLB_DEV_FL_UP, &dev->flags)) {
331 mutex_lock(&lock);
332 dev->power = newp;
333 null_del_dev(dev->nullb);
334 mutex_unlock(&lock);
335 }
336 clear_bit(NULLB_DEV_FL_CONFIGURED, &dev->flags);
337 }
338
339 return count;
340 }
341
342 CONFIGFS_ATTR(nullb_device_, power);
343
nullb_device_badblocks_show(struct config_item * item,char * page)344 static ssize_t nullb_device_badblocks_show(struct config_item *item, char *page)
345 {
346 struct nullb_device *t_dev = to_nullb_device(item);
347
348 return badblocks_show(&t_dev->badblocks, page, 0);
349 }
350
nullb_device_badblocks_store(struct config_item * item,const char * page,size_t count)351 static ssize_t nullb_device_badblocks_store(struct config_item *item,
352 const char *page, size_t count)
353 {
354 struct nullb_device *t_dev = to_nullb_device(item);
355 char *orig, *buf, *tmp;
356 u64 start, end;
357 int ret;
358
359 orig = kstrndup(page, count, GFP_KERNEL);
360 if (!orig)
361 return -ENOMEM;
362
363 buf = strstrip(orig);
364
365 ret = -EINVAL;
366 if (buf[0] != '+' && buf[0] != '-')
367 goto out;
368 tmp = strchr(&buf[1], '-');
369 if (!tmp)
370 goto out;
371 *tmp = '\0';
372 ret = kstrtoull(buf + 1, 0, &start);
373 if (ret)
374 goto out;
375 ret = kstrtoull(tmp + 1, 0, &end);
376 if (ret)
377 goto out;
378 ret = -EINVAL;
379 if (start > end)
380 goto out;
381 /* enable badblocks */
382 cmpxchg(&t_dev->badblocks.shift, -1, 0);
383 if (buf[0] == '+')
384 ret = badblocks_set(&t_dev->badblocks, start,
385 end - start + 1, 1);
386 else
387 ret = badblocks_clear(&t_dev->badblocks, start,
388 end - start + 1);
389 if (ret == 0)
390 ret = count;
391 out:
392 kfree(orig);
393 return ret;
394 }
395 CONFIGFS_ATTR(nullb_device_, badblocks);
396
397 static struct configfs_attribute *nullb_device_attrs[] = {
398 &nullb_device_attr_size,
399 &nullb_device_attr_completion_nsec,
400 &nullb_device_attr_submit_queues,
401 &nullb_device_attr_home_node,
402 &nullb_device_attr_queue_mode,
403 &nullb_device_attr_blocksize,
404 &nullb_device_attr_irqmode,
405 &nullb_device_attr_hw_queue_depth,
406 &nullb_device_attr_index,
407 &nullb_device_attr_blocking,
408 &nullb_device_attr_use_per_node_hctx,
409 &nullb_device_attr_power,
410 &nullb_device_attr_memory_backed,
411 &nullb_device_attr_discard,
412 &nullb_device_attr_mbps,
413 &nullb_device_attr_cache_size,
414 &nullb_device_attr_badblocks,
415 &nullb_device_attr_zoned,
416 &nullb_device_attr_zone_size,
417 &nullb_device_attr_zone_nr_conv,
418 NULL,
419 };
420
nullb_device_release(struct config_item * item)421 static void nullb_device_release(struct config_item *item)
422 {
423 struct nullb_device *dev = to_nullb_device(item);
424
425 null_free_device_storage(dev, false);
426 null_free_dev(dev);
427 }
428
429 static struct configfs_item_operations nullb_device_ops = {
430 .release = nullb_device_release,
431 };
432
433 static const struct config_item_type nullb_device_type = {
434 .ct_item_ops = &nullb_device_ops,
435 .ct_attrs = nullb_device_attrs,
436 .ct_owner = THIS_MODULE,
437 };
438
439 static struct
nullb_group_make_item(struct config_group * group,const char * name)440 config_item *nullb_group_make_item(struct config_group *group, const char *name)
441 {
442 struct nullb_device *dev;
443
444 dev = null_alloc_dev();
445 if (!dev)
446 return ERR_PTR(-ENOMEM);
447
448 config_item_init_type_name(&dev->item, name, &nullb_device_type);
449
450 return &dev->item;
451 }
452
453 static void
nullb_group_drop_item(struct config_group * group,struct config_item * item)454 nullb_group_drop_item(struct config_group *group, struct config_item *item)
455 {
456 struct nullb_device *dev = to_nullb_device(item);
457
458 if (test_and_clear_bit(NULLB_DEV_FL_UP, &dev->flags)) {
459 mutex_lock(&lock);
460 dev->power = false;
461 null_del_dev(dev->nullb);
462 mutex_unlock(&lock);
463 }
464
465 config_item_put(item);
466 }
467
memb_group_features_show(struct config_item * item,char * page)468 static ssize_t memb_group_features_show(struct config_item *item, char *page)
469 {
470 return snprintf(page, PAGE_SIZE, "memory_backed,discard,bandwidth,cache,badblocks,zoned,zone_size\n");
471 }
472
473 CONFIGFS_ATTR_RO(memb_group_, features);
474
475 static struct configfs_attribute *nullb_group_attrs[] = {
476 &memb_group_attr_features,
477 NULL,
478 };
479
480 static struct configfs_group_operations nullb_group_ops = {
481 .make_item = nullb_group_make_item,
482 .drop_item = nullb_group_drop_item,
483 };
484
485 static const struct config_item_type nullb_group_type = {
486 .ct_group_ops = &nullb_group_ops,
487 .ct_attrs = nullb_group_attrs,
488 .ct_owner = THIS_MODULE,
489 };
490
491 static struct configfs_subsystem nullb_subsys = {
492 .su_group = {
493 .cg_item = {
494 .ci_namebuf = "nullb",
495 .ci_type = &nullb_group_type,
496 },
497 },
498 };
499
null_cache_active(struct nullb * nullb)500 static inline int null_cache_active(struct nullb *nullb)
501 {
502 return test_bit(NULLB_DEV_FL_CACHE, &nullb->dev->flags);
503 }
504
null_alloc_dev(void)505 static struct nullb_device *null_alloc_dev(void)
506 {
507 struct nullb_device *dev;
508
509 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
510 if (!dev)
511 return NULL;
512 INIT_RADIX_TREE(&dev->data, GFP_ATOMIC);
513 INIT_RADIX_TREE(&dev->cache, GFP_ATOMIC);
514 if (badblocks_init(&dev->badblocks, 0)) {
515 kfree(dev);
516 return NULL;
517 }
518
519 dev->size = g_gb * 1024;
520 dev->completion_nsec = g_completion_nsec;
521 dev->submit_queues = g_submit_queues;
522 dev->home_node = g_home_node;
523 dev->queue_mode = g_queue_mode;
524 dev->blocksize = g_bs;
525 dev->irqmode = g_irqmode;
526 dev->hw_queue_depth = g_hw_queue_depth;
527 dev->blocking = g_blocking;
528 dev->use_per_node_hctx = g_use_per_node_hctx;
529 dev->zoned = g_zoned;
530 dev->zone_size = g_zone_size;
531 dev->zone_nr_conv = g_zone_nr_conv;
532 return dev;
533 }
534
null_free_dev(struct nullb_device * dev)535 static void null_free_dev(struct nullb_device *dev)
536 {
537 if (!dev)
538 return;
539
540 null_zone_exit(dev);
541 badblocks_exit(&dev->badblocks);
542 kfree(dev);
543 }
544
put_tag(struct nullb_queue * nq,unsigned int tag)545 static void put_tag(struct nullb_queue *nq, unsigned int tag)
546 {
547 clear_bit_unlock(tag, nq->tag_map);
548
549 if (waitqueue_active(&nq->wait))
550 wake_up(&nq->wait);
551 }
552
get_tag(struct nullb_queue * nq)553 static unsigned int get_tag(struct nullb_queue *nq)
554 {
555 unsigned int tag;
556
557 do {
558 tag = find_first_zero_bit(nq->tag_map, nq->queue_depth);
559 if (tag >= nq->queue_depth)
560 return -1U;
561 } while (test_and_set_bit_lock(tag, nq->tag_map));
562
563 return tag;
564 }
565
free_cmd(struct nullb_cmd * cmd)566 static void free_cmd(struct nullb_cmd *cmd)
567 {
568 put_tag(cmd->nq, cmd->tag);
569 }
570
571 static enum hrtimer_restart null_cmd_timer_expired(struct hrtimer *timer);
572
__alloc_cmd(struct nullb_queue * nq)573 static struct nullb_cmd *__alloc_cmd(struct nullb_queue *nq)
574 {
575 struct nullb_cmd *cmd;
576 unsigned int tag;
577
578 tag = get_tag(nq);
579 if (tag != -1U) {
580 cmd = &nq->cmds[tag];
581 cmd->tag = tag;
582 cmd->nq = nq;
583 if (nq->dev->irqmode == NULL_IRQ_TIMER) {
584 hrtimer_init(&cmd->timer, CLOCK_MONOTONIC,
585 HRTIMER_MODE_REL);
586 cmd->timer.function = null_cmd_timer_expired;
587 }
588 return cmd;
589 }
590
591 return NULL;
592 }
593
alloc_cmd(struct nullb_queue * nq,int can_wait)594 static struct nullb_cmd *alloc_cmd(struct nullb_queue *nq, int can_wait)
595 {
596 struct nullb_cmd *cmd;
597 DEFINE_WAIT(wait);
598
599 cmd = __alloc_cmd(nq);
600 if (cmd || !can_wait)
601 return cmd;
602
603 do {
604 prepare_to_wait(&nq->wait, &wait, TASK_UNINTERRUPTIBLE);
605 cmd = __alloc_cmd(nq);
606 if (cmd)
607 break;
608
609 io_schedule();
610 } while (1);
611
612 finish_wait(&nq->wait, &wait);
613 return cmd;
614 }
615
end_cmd(struct nullb_cmd * cmd)616 static void end_cmd(struct nullb_cmd *cmd)
617 {
618 int queue_mode = cmd->nq->dev->queue_mode;
619
620 switch (queue_mode) {
621 case NULL_Q_MQ:
622 blk_mq_end_request(cmd->rq, cmd->error);
623 return;
624 case NULL_Q_BIO:
625 cmd->bio->bi_status = cmd->error;
626 bio_endio(cmd->bio);
627 break;
628 }
629
630 free_cmd(cmd);
631 }
632
null_cmd_timer_expired(struct hrtimer * timer)633 static enum hrtimer_restart null_cmd_timer_expired(struct hrtimer *timer)
634 {
635 end_cmd(container_of(timer, struct nullb_cmd, timer));
636
637 return HRTIMER_NORESTART;
638 }
639
null_cmd_end_timer(struct nullb_cmd * cmd)640 static void null_cmd_end_timer(struct nullb_cmd *cmd)
641 {
642 ktime_t kt = cmd->nq->dev->completion_nsec;
643
644 hrtimer_start(&cmd->timer, kt, HRTIMER_MODE_REL);
645 }
646
null_complete_rq(struct request * rq)647 static void null_complete_rq(struct request *rq)
648 {
649 end_cmd(blk_mq_rq_to_pdu(rq));
650 }
651
null_alloc_page(gfp_t gfp_flags)652 static struct nullb_page *null_alloc_page(gfp_t gfp_flags)
653 {
654 struct nullb_page *t_page;
655
656 t_page = kmalloc(sizeof(struct nullb_page), gfp_flags);
657 if (!t_page)
658 goto out;
659
660 t_page->page = alloc_pages(gfp_flags, 0);
661 if (!t_page->page)
662 goto out_freepage;
663
664 memset(t_page->bitmap, 0, sizeof(t_page->bitmap));
665 return t_page;
666 out_freepage:
667 kfree(t_page);
668 out:
669 return NULL;
670 }
671
null_free_page(struct nullb_page * t_page)672 static void null_free_page(struct nullb_page *t_page)
673 {
674 __set_bit(NULLB_PAGE_FREE, t_page->bitmap);
675 if (test_bit(NULLB_PAGE_LOCK, t_page->bitmap))
676 return;
677 __free_page(t_page->page);
678 kfree(t_page);
679 }
680
null_page_empty(struct nullb_page * page)681 static bool null_page_empty(struct nullb_page *page)
682 {
683 int size = MAP_SZ - 2;
684
685 return find_first_bit(page->bitmap, size) == size;
686 }
687
null_free_sector(struct nullb * nullb,sector_t sector,bool is_cache)688 static void null_free_sector(struct nullb *nullb, sector_t sector,
689 bool is_cache)
690 {
691 unsigned int sector_bit;
692 u64 idx;
693 struct nullb_page *t_page, *ret;
694 struct radix_tree_root *root;
695
696 root = is_cache ? &nullb->dev->cache : &nullb->dev->data;
697 idx = sector >> PAGE_SECTORS_SHIFT;
698 sector_bit = (sector & SECTOR_MASK);
699
700 t_page = radix_tree_lookup(root, idx);
701 if (t_page) {
702 __clear_bit(sector_bit, t_page->bitmap);
703
704 if (null_page_empty(t_page)) {
705 ret = radix_tree_delete_item(root, idx, t_page);
706 WARN_ON(ret != t_page);
707 null_free_page(ret);
708 if (is_cache)
709 nullb->dev->curr_cache -= PAGE_SIZE;
710 }
711 }
712 }
713
null_radix_tree_insert(struct nullb * nullb,u64 idx,struct nullb_page * t_page,bool is_cache)714 static struct nullb_page *null_radix_tree_insert(struct nullb *nullb, u64 idx,
715 struct nullb_page *t_page, bool is_cache)
716 {
717 struct radix_tree_root *root;
718
719 root = is_cache ? &nullb->dev->cache : &nullb->dev->data;
720
721 if (radix_tree_insert(root, idx, t_page)) {
722 null_free_page(t_page);
723 t_page = radix_tree_lookup(root, idx);
724 WARN_ON(!t_page || t_page->page->index != idx);
725 } else if (is_cache)
726 nullb->dev->curr_cache += PAGE_SIZE;
727
728 return t_page;
729 }
730
null_free_device_storage(struct nullb_device * dev,bool is_cache)731 static void null_free_device_storage(struct nullb_device *dev, bool is_cache)
732 {
733 unsigned long pos = 0;
734 int nr_pages;
735 struct nullb_page *ret, *t_pages[FREE_BATCH];
736 struct radix_tree_root *root;
737
738 root = is_cache ? &dev->cache : &dev->data;
739
740 do {
741 int i;
742
743 nr_pages = radix_tree_gang_lookup(root,
744 (void **)t_pages, pos, FREE_BATCH);
745
746 for (i = 0; i < nr_pages; i++) {
747 pos = t_pages[i]->page->index;
748 ret = radix_tree_delete_item(root, pos, t_pages[i]);
749 WARN_ON(ret != t_pages[i]);
750 null_free_page(ret);
751 }
752
753 pos++;
754 } while (nr_pages == FREE_BATCH);
755
756 if (is_cache)
757 dev->curr_cache = 0;
758 }
759
__null_lookup_page(struct nullb * nullb,sector_t sector,bool for_write,bool is_cache)760 static struct nullb_page *__null_lookup_page(struct nullb *nullb,
761 sector_t sector, bool for_write, bool is_cache)
762 {
763 unsigned int sector_bit;
764 u64 idx;
765 struct nullb_page *t_page;
766 struct radix_tree_root *root;
767
768 idx = sector >> PAGE_SECTORS_SHIFT;
769 sector_bit = (sector & SECTOR_MASK);
770
771 root = is_cache ? &nullb->dev->cache : &nullb->dev->data;
772 t_page = radix_tree_lookup(root, idx);
773 WARN_ON(t_page && t_page->page->index != idx);
774
775 if (t_page && (for_write || test_bit(sector_bit, t_page->bitmap)))
776 return t_page;
777
778 return NULL;
779 }
780
null_lookup_page(struct nullb * nullb,sector_t sector,bool for_write,bool ignore_cache)781 static struct nullb_page *null_lookup_page(struct nullb *nullb,
782 sector_t sector, bool for_write, bool ignore_cache)
783 {
784 struct nullb_page *page = NULL;
785
786 if (!ignore_cache)
787 page = __null_lookup_page(nullb, sector, for_write, true);
788 if (page)
789 return page;
790 return __null_lookup_page(nullb, sector, for_write, false);
791 }
792
null_insert_page(struct nullb * nullb,sector_t sector,bool ignore_cache)793 static struct nullb_page *null_insert_page(struct nullb *nullb,
794 sector_t sector, bool ignore_cache)
795 __releases(&nullb->lock)
796 __acquires(&nullb->lock)
797 {
798 u64 idx;
799 struct nullb_page *t_page;
800
801 t_page = null_lookup_page(nullb, sector, true, ignore_cache);
802 if (t_page)
803 return t_page;
804
805 spin_unlock_irq(&nullb->lock);
806
807 t_page = null_alloc_page(GFP_NOIO);
808 if (!t_page)
809 goto out_lock;
810
811 if (radix_tree_preload(GFP_NOIO))
812 goto out_freepage;
813
814 spin_lock_irq(&nullb->lock);
815 idx = sector >> PAGE_SECTORS_SHIFT;
816 t_page->page->index = idx;
817 t_page = null_radix_tree_insert(nullb, idx, t_page, !ignore_cache);
818 radix_tree_preload_end();
819
820 return t_page;
821 out_freepage:
822 null_free_page(t_page);
823 out_lock:
824 spin_lock_irq(&nullb->lock);
825 return null_lookup_page(nullb, sector, true, ignore_cache);
826 }
827
null_flush_cache_page(struct nullb * nullb,struct nullb_page * c_page)828 static int null_flush_cache_page(struct nullb *nullb, struct nullb_page *c_page)
829 {
830 int i;
831 unsigned int offset;
832 u64 idx;
833 struct nullb_page *t_page, *ret;
834 void *dst, *src;
835
836 idx = c_page->page->index;
837
838 t_page = null_insert_page(nullb, idx << PAGE_SECTORS_SHIFT, true);
839
840 __clear_bit(NULLB_PAGE_LOCK, c_page->bitmap);
841 if (test_bit(NULLB_PAGE_FREE, c_page->bitmap)) {
842 null_free_page(c_page);
843 if (t_page && null_page_empty(t_page)) {
844 ret = radix_tree_delete_item(&nullb->dev->data,
845 idx, t_page);
846 null_free_page(t_page);
847 }
848 return 0;
849 }
850
851 if (!t_page)
852 return -ENOMEM;
853
854 src = kmap_atomic(c_page->page);
855 dst = kmap_atomic(t_page->page);
856
857 for (i = 0; i < PAGE_SECTORS;
858 i += (nullb->dev->blocksize >> SECTOR_SHIFT)) {
859 if (test_bit(i, c_page->bitmap)) {
860 offset = (i << SECTOR_SHIFT);
861 memcpy(dst + offset, src + offset,
862 nullb->dev->blocksize);
863 __set_bit(i, t_page->bitmap);
864 }
865 }
866
867 kunmap_atomic(dst);
868 kunmap_atomic(src);
869
870 ret = radix_tree_delete_item(&nullb->dev->cache, idx, c_page);
871 null_free_page(ret);
872 nullb->dev->curr_cache -= PAGE_SIZE;
873
874 return 0;
875 }
876
null_make_cache_space(struct nullb * nullb,unsigned long n)877 static int null_make_cache_space(struct nullb *nullb, unsigned long n)
878 {
879 int i, err, nr_pages;
880 struct nullb_page *c_pages[FREE_BATCH];
881 unsigned long flushed = 0, one_round;
882
883 again:
884 if ((nullb->dev->cache_size * 1024 * 1024) >
885 nullb->dev->curr_cache + n || nullb->dev->curr_cache == 0)
886 return 0;
887
888 nr_pages = radix_tree_gang_lookup(&nullb->dev->cache,
889 (void **)c_pages, nullb->cache_flush_pos, FREE_BATCH);
890 /*
891 * nullb_flush_cache_page could unlock before using the c_pages. To
892 * avoid race, we don't allow page free
893 */
894 for (i = 0; i < nr_pages; i++) {
895 nullb->cache_flush_pos = c_pages[i]->page->index;
896 /*
897 * We found the page which is being flushed to disk by other
898 * threads
899 */
900 if (test_bit(NULLB_PAGE_LOCK, c_pages[i]->bitmap))
901 c_pages[i] = NULL;
902 else
903 __set_bit(NULLB_PAGE_LOCK, c_pages[i]->bitmap);
904 }
905
906 one_round = 0;
907 for (i = 0; i < nr_pages; i++) {
908 if (c_pages[i] == NULL)
909 continue;
910 err = null_flush_cache_page(nullb, c_pages[i]);
911 if (err)
912 return err;
913 one_round++;
914 }
915 flushed += one_round << PAGE_SHIFT;
916
917 if (n > flushed) {
918 if (nr_pages == 0)
919 nullb->cache_flush_pos = 0;
920 if (one_round == 0) {
921 /* give other threads a chance */
922 spin_unlock_irq(&nullb->lock);
923 spin_lock_irq(&nullb->lock);
924 }
925 goto again;
926 }
927 return 0;
928 }
929
copy_to_nullb(struct nullb * nullb,struct page * source,unsigned int off,sector_t sector,size_t n,bool is_fua)930 static int copy_to_nullb(struct nullb *nullb, struct page *source,
931 unsigned int off, sector_t sector, size_t n, bool is_fua)
932 {
933 size_t temp, count = 0;
934 unsigned int offset;
935 struct nullb_page *t_page;
936 void *dst, *src;
937
938 while (count < n) {
939 temp = min_t(size_t, nullb->dev->blocksize, n - count);
940
941 if (null_cache_active(nullb) && !is_fua)
942 null_make_cache_space(nullb, PAGE_SIZE);
943
944 offset = (sector & SECTOR_MASK) << SECTOR_SHIFT;
945 t_page = null_insert_page(nullb, sector,
946 !null_cache_active(nullb) || is_fua);
947 if (!t_page)
948 return -ENOSPC;
949
950 src = kmap_atomic(source);
951 dst = kmap_atomic(t_page->page);
952 memcpy(dst + offset, src + off + count, temp);
953 kunmap_atomic(dst);
954 kunmap_atomic(src);
955
956 __set_bit(sector & SECTOR_MASK, t_page->bitmap);
957
958 if (is_fua)
959 null_free_sector(nullb, sector, true);
960
961 count += temp;
962 sector += temp >> SECTOR_SHIFT;
963 }
964 return 0;
965 }
966
copy_from_nullb(struct nullb * nullb,struct page * dest,unsigned int off,sector_t sector,size_t n)967 static int copy_from_nullb(struct nullb *nullb, struct page *dest,
968 unsigned int off, sector_t sector, size_t n)
969 {
970 size_t temp, count = 0;
971 unsigned int offset;
972 struct nullb_page *t_page;
973 void *dst, *src;
974
975 while (count < n) {
976 temp = min_t(size_t, nullb->dev->blocksize, n - count);
977
978 offset = (sector & SECTOR_MASK) << SECTOR_SHIFT;
979 t_page = null_lookup_page(nullb, sector, false,
980 !null_cache_active(nullb));
981
982 dst = kmap_atomic(dest);
983 if (!t_page) {
984 memset(dst + off + count, 0, temp);
985 goto next;
986 }
987 src = kmap_atomic(t_page->page);
988 memcpy(dst + off + count, src + offset, temp);
989 kunmap_atomic(src);
990 next:
991 kunmap_atomic(dst);
992
993 count += temp;
994 sector += temp >> SECTOR_SHIFT;
995 }
996 return 0;
997 }
998
nullb_fill_pattern(struct nullb * nullb,struct page * page,unsigned int len,unsigned int off)999 static void nullb_fill_pattern(struct nullb *nullb, struct page *page,
1000 unsigned int len, unsigned int off)
1001 {
1002 void *dst;
1003
1004 dst = kmap_atomic(page);
1005 memset(dst + off, 0xFF, len);
1006 kunmap_atomic(dst);
1007 }
1008
null_handle_discard(struct nullb * nullb,sector_t sector,size_t n)1009 static void null_handle_discard(struct nullb *nullb, sector_t sector, size_t n)
1010 {
1011 size_t temp;
1012
1013 spin_lock_irq(&nullb->lock);
1014 while (n > 0) {
1015 temp = min_t(size_t, n, nullb->dev->blocksize);
1016 null_free_sector(nullb, sector, false);
1017 if (null_cache_active(nullb))
1018 null_free_sector(nullb, sector, true);
1019 sector += temp >> SECTOR_SHIFT;
1020 n -= temp;
1021 }
1022 spin_unlock_irq(&nullb->lock);
1023 }
1024
null_handle_flush(struct nullb * nullb)1025 static int null_handle_flush(struct nullb *nullb)
1026 {
1027 int err;
1028
1029 if (!null_cache_active(nullb))
1030 return 0;
1031
1032 spin_lock_irq(&nullb->lock);
1033 while (true) {
1034 err = null_make_cache_space(nullb,
1035 nullb->dev->cache_size * 1024 * 1024);
1036 if (err || nullb->dev->curr_cache == 0)
1037 break;
1038 }
1039
1040 WARN_ON(!radix_tree_empty(&nullb->dev->cache));
1041 spin_unlock_irq(&nullb->lock);
1042 return err;
1043 }
1044
null_transfer(struct nullb * nullb,struct page * page,unsigned int len,unsigned int off,bool is_write,sector_t sector,bool is_fua)1045 static int null_transfer(struct nullb *nullb, struct page *page,
1046 unsigned int len, unsigned int off, bool is_write, sector_t sector,
1047 bool is_fua)
1048 {
1049 struct nullb_device *dev = nullb->dev;
1050 unsigned int valid_len = len;
1051 int err = 0;
1052
1053 if (!is_write) {
1054 if (dev->zoned)
1055 valid_len = null_zone_valid_read_len(nullb,
1056 sector, len);
1057
1058 if (valid_len) {
1059 err = copy_from_nullb(nullb, page, off,
1060 sector, valid_len);
1061 off += valid_len;
1062 len -= valid_len;
1063 }
1064
1065 if (len)
1066 nullb_fill_pattern(nullb, page, len, off);
1067 flush_dcache_page(page);
1068 } else {
1069 flush_dcache_page(page);
1070 err = copy_to_nullb(nullb, page, off, sector, len, is_fua);
1071 }
1072
1073 return err;
1074 }
1075
null_handle_rq(struct nullb_cmd * cmd)1076 static int null_handle_rq(struct nullb_cmd *cmd)
1077 {
1078 struct request *rq = cmd->rq;
1079 struct nullb *nullb = cmd->nq->dev->nullb;
1080 int err;
1081 unsigned int len;
1082 sector_t sector;
1083 struct req_iterator iter;
1084 struct bio_vec bvec;
1085
1086 sector = blk_rq_pos(rq);
1087
1088 if (req_op(rq) == REQ_OP_DISCARD) {
1089 null_handle_discard(nullb, sector, blk_rq_bytes(rq));
1090 return 0;
1091 }
1092
1093 spin_lock_irq(&nullb->lock);
1094 rq_for_each_segment(bvec, rq, iter) {
1095 len = bvec.bv_len;
1096 err = null_transfer(nullb, bvec.bv_page, len, bvec.bv_offset,
1097 op_is_write(req_op(rq)), sector,
1098 req_op(rq) & REQ_FUA);
1099 if (err) {
1100 spin_unlock_irq(&nullb->lock);
1101 return err;
1102 }
1103 sector += len >> SECTOR_SHIFT;
1104 }
1105 spin_unlock_irq(&nullb->lock);
1106
1107 return 0;
1108 }
1109
null_handle_bio(struct nullb_cmd * cmd)1110 static int null_handle_bio(struct nullb_cmd *cmd)
1111 {
1112 struct bio *bio = cmd->bio;
1113 struct nullb *nullb = cmd->nq->dev->nullb;
1114 int err;
1115 unsigned int len;
1116 sector_t sector;
1117 struct bio_vec bvec;
1118 struct bvec_iter iter;
1119
1120 sector = bio->bi_iter.bi_sector;
1121
1122 if (bio_op(bio) == REQ_OP_DISCARD) {
1123 null_handle_discard(nullb, sector,
1124 bio_sectors(bio) << SECTOR_SHIFT);
1125 return 0;
1126 }
1127
1128 spin_lock_irq(&nullb->lock);
1129 bio_for_each_segment(bvec, bio, iter) {
1130 len = bvec.bv_len;
1131 err = null_transfer(nullb, bvec.bv_page, len, bvec.bv_offset,
1132 op_is_write(bio_op(bio)), sector,
1133 bio->bi_opf & REQ_FUA);
1134 if (err) {
1135 spin_unlock_irq(&nullb->lock);
1136 return err;
1137 }
1138 sector += len >> SECTOR_SHIFT;
1139 }
1140 spin_unlock_irq(&nullb->lock);
1141 return 0;
1142 }
1143
null_stop_queue(struct nullb * nullb)1144 static void null_stop_queue(struct nullb *nullb)
1145 {
1146 struct request_queue *q = nullb->q;
1147
1148 if (nullb->dev->queue_mode == NULL_Q_MQ)
1149 blk_mq_stop_hw_queues(q);
1150 }
1151
null_restart_queue_async(struct nullb * nullb)1152 static void null_restart_queue_async(struct nullb *nullb)
1153 {
1154 struct request_queue *q = nullb->q;
1155
1156 if (nullb->dev->queue_mode == NULL_Q_MQ)
1157 blk_mq_start_stopped_hw_queues(q, true);
1158 }
1159
null_handle_throttled(struct nullb_cmd * cmd)1160 static inline blk_status_t null_handle_throttled(struct nullb_cmd *cmd)
1161 {
1162 struct nullb_device *dev = cmd->nq->dev;
1163 struct nullb *nullb = dev->nullb;
1164 blk_status_t sts = BLK_STS_OK;
1165 struct request *rq = cmd->rq;
1166
1167 if (!hrtimer_active(&nullb->bw_timer))
1168 hrtimer_restart(&nullb->bw_timer);
1169
1170 if (atomic_long_sub_return(blk_rq_bytes(rq), &nullb->cur_bytes) < 0) {
1171 null_stop_queue(nullb);
1172 /* race with timer */
1173 if (atomic_long_read(&nullb->cur_bytes) > 0)
1174 null_restart_queue_async(nullb);
1175 /* requeue request */
1176 sts = BLK_STS_DEV_RESOURCE;
1177 }
1178 return sts;
1179 }
1180
null_handle_badblocks(struct nullb_cmd * cmd,sector_t sector,sector_t nr_sectors)1181 static inline blk_status_t null_handle_badblocks(struct nullb_cmd *cmd,
1182 sector_t sector,
1183 sector_t nr_sectors)
1184 {
1185 struct badblocks *bb = &cmd->nq->dev->badblocks;
1186 sector_t first_bad;
1187 int bad_sectors;
1188
1189 if (badblocks_check(bb, sector, nr_sectors, &first_bad, &bad_sectors))
1190 return BLK_STS_IOERR;
1191
1192 return BLK_STS_OK;
1193 }
1194
null_handle_memory_backed(struct nullb_cmd * cmd,enum req_opf op)1195 static inline blk_status_t null_handle_memory_backed(struct nullb_cmd *cmd,
1196 enum req_opf op)
1197 {
1198 struct nullb_device *dev = cmd->nq->dev;
1199 int err;
1200
1201 if (dev->queue_mode == NULL_Q_BIO)
1202 err = null_handle_bio(cmd);
1203 else
1204 err = null_handle_rq(cmd);
1205
1206 return errno_to_blk_status(err);
1207 }
1208
nullb_complete_cmd(struct nullb_cmd * cmd)1209 static inline void nullb_complete_cmd(struct nullb_cmd *cmd)
1210 {
1211 /* Complete IO by inline, softirq or timer */
1212 switch (cmd->nq->dev->irqmode) {
1213 case NULL_IRQ_SOFTIRQ:
1214 switch (cmd->nq->dev->queue_mode) {
1215 case NULL_Q_MQ:
1216 blk_mq_complete_request(cmd->rq);
1217 break;
1218 case NULL_Q_BIO:
1219 /*
1220 * XXX: no proper submitting cpu information available.
1221 */
1222 end_cmd(cmd);
1223 break;
1224 }
1225 break;
1226 case NULL_IRQ_NONE:
1227 end_cmd(cmd);
1228 break;
1229 case NULL_IRQ_TIMER:
1230 null_cmd_end_timer(cmd);
1231 break;
1232 }
1233 }
1234
null_handle_cmd(struct nullb_cmd * cmd,sector_t sector,sector_t nr_sectors,enum req_opf op)1235 static blk_status_t null_handle_cmd(struct nullb_cmd *cmd, sector_t sector,
1236 sector_t nr_sectors, enum req_opf op)
1237 {
1238 struct nullb_device *dev = cmd->nq->dev;
1239 struct nullb *nullb = dev->nullb;
1240 blk_status_t sts;
1241
1242 if (test_bit(NULLB_DEV_FL_THROTTLED, &dev->flags)) {
1243 sts = null_handle_throttled(cmd);
1244 if (sts != BLK_STS_OK)
1245 return sts;
1246 }
1247
1248 if (op == REQ_OP_FLUSH) {
1249 cmd->error = errno_to_blk_status(null_handle_flush(nullb));
1250 goto out;
1251 }
1252
1253 if (nullb->dev->badblocks.shift != -1) {
1254 cmd->error = null_handle_badblocks(cmd, sector, nr_sectors);
1255 if (cmd->error != BLK_STS_OK)
1256 goto out;
1257 }
1258
1259 if (dev->memory_backed)
1260 cmd->error = null_handle_memory_backed(cmd, op);
1261
1262 if (!cmd->error && dev->zoned)
1263 cmd->error = null_handle_zoned(cmd, op, sector, nr_sectors);
1264
1265 out:
1266 nullb_complete_cmd(cmd);
1267 return BLK_STS_OK;
1268 }
1269
nullb_bwtimer_fn(struct hrtimer * timer)1270 static enum hrtimer_restart nullb_bwtimer_fn(struct hrtimer *timer)
1271 {
1272 struct nullb *nullb = container_of(timer, struct nullb, bw_timer);
1273 ktime_t timer_interval = ktime_set(0, TIMER_INTERVAL);
1274 unsigned int mbps = nullb->dev->mbps;
1275
1276 if (atomic_long_read(&nullb->cur_bytes) == mb_per_tick(mbps))
1277 return HRTIMER_NORESTART;
1278
1279 atomic_long_set(&nullb->cur_bytes, mb_per_tick(mbps));
1280 null_restart_queue_async(nullb);
1281
1282 hrtimer_forward_now(&nullb->bw_timer, timer_interval);
1283
1284 return HRTIMER_RESTART;
1285 }
1286
nullb_setup_bwtimer(struct nullb * nullb)1287 static void nullb_setup_bwtimer(struct nullb *nullb)
1288 {
1289 ktime_t timer_interval = ktime_set(0, TIMER_INTERVAL);
1290
1291 hrtimer_init(&nullb->bw_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
1292 nullb->bw_timer.function = nullb_bwtimer_fn;
1293 atomic_long_set(&nullb->cur_bytes, mb_per_tick(nullb->dev->mbps));
1294 hrtimer_start(&nullb->bw_timer, timer_interval, HRTIMER_MODE_REL);
1295 }
1296
nullb_to_queue(struct nullb * nullb)1297 static struct nullb_queue *nullb_to_queue(struct nullb *nullb)
1298 {
1299 int index = 0;
1300
1301 if (nullb->nr_queues != 1)
1302 index = raw_smp_processor_id() / ((nr_cpu_ids + nullb->nr_queues - 1) / nullb->nr_queues);
1303
1304 return &nullb->queues[index];
1305 }
1306
null_queue_bio(struct request_queue * q,struct bio * bio)1307 static blk_qc_t null_queue_bio(struct request_queue *q, struct bio *bio)
1308 {
1309 sector_t sector = bio->bi_iter.bi_sector;
1310 sector_t nr_sectors = bio_sectors(bio);
1311 struct nullb *nullb = q->queuedata;
1312 struct nullb_queue *nq = nullb_to_queue(nullb);
1313 struct nullb_cmd *cmd;
1314
1315 cmd = alloc_cmd(nq, 1);
1316 cmd->bio = bio;
1317
1318 null_handle_cmd(cmd, sector, nr_sectors, bio_op(bio));
1319 return BLK_QC_T_NONE;
1320 }
1321
should_timeout_request(struct request * rq)1322 static bool should_timeout_request(struct request *rq)
1323 {
1324 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
1325 if (g_timeout_str[0])
1326 return should_fail(&null_timeout_attr, 1);
1327 #endif
1328 return false;
1329 }
1330
should_requeue_request(struct request * rq)1331 static bool should_requeue_request(struct request *rq)
1332 {
1333 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
1334 if (g_requeue_str[0])
1335 return should_fail(&null_requeue_attr, 1);
1336 #endif
1337 return false;
1338 }
1339
null_timeout_rq(struct request * rq,bool res)1340 static enum blk_eh_timer_return null_timeout_rq(struct request *rq, bool res)
1341 {
1342 pr_info("rq %p timed out\n", rq);
1343 blk_mq_complete_request(rq);
1344 return BLK_EH_DONE;
1345 }
1346
null_queue_rq(struct blk_mq_hw_ctx * hctx,const struct blk_mq_queue_data * bd)1347 static blk_status_t null_queue_rq(struct blk_mq_hw_ctx *hctx,
1348 const struct blk_mq_queue_data *bd)
1349 {
1350 struct nullb_cmd *cmd = blk_mq_rq_to_pdu(bd->rq);
1351 struct nullb_queue *nq = hctx->driver_data;
1352 sector_t nr_sectors = blk_rq_sectors(bd->rq);
1353 sector_t sector = blk_rq_pos(bd->rq);
1354
1355 might_sleep_if(hctx->flags & BLK_MQ_F_BLOCKING);
1356
1357 if (nq->dev->irqmode == NULL_IRQ_TIMER) {
1358 hrtimer_init(&cmd->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
1359 cmd->timer.function = null_cmd_timer_expired;
1360 }
1361 cmd->rq = bd->rq;
1362 cmd->nq = nq;
1363
1364 blk_mq_start_request(bd->rq);
1365
1366 if (should_requeue_request(bd->rq)) {
1367 /*
1368 * Alternate between hitting the core BUSY path, and the
1369 * driver driven requeue path
1370 */
1371 nq->requeue_selection++;
1372 if (nq->requeue_selection & 1)
1373 return BLK_STS_RESOURCE;
1374 else {
1375 blk_mq_requeue_request(bd->rq, true);
1376 return BLK_STS_OK;
1377 }
1378 }
1379 if (should_timeout_request(bd->rq))
1380 return BLK_STS_OK;
1381
1382 return null_handle_cmd(cmd, sector, nr_sectors, req_op(bd->rq));
1383 }
1384
1385 static const struct blk_mq_ops null_mq_ops = {
1386 .queue_rq = null_queue_rq,
1387 .complete = null_complete_rq,
1388 .timeout = null_timeout_rq,
1389 };
1390
cleanup_queue(struct nullb_queue * nq)1391 static void cleanup_queue(struct nullb_queue *nq)
1392 {
1393 kfree(nq->tag_map);
1394 kfree(nq->cmds);
1395 }
1396
cleanup_queues(struct nullb * nullb)1397 static void cleanup_queues(struct nullb *nullb)
1398 {
1399 int i;
1400
1401 for (i = 0; i < nullb->nr_queues; i++)
1402 cleanup_queue(&nullb->queues[i]);
1403
1404 kfree(nullb->queues);
1405 }
1406
null_del_dev(struct nullb * nullb)1407 static void null_del_dev(struct nullb *nullb)
1408 {
1409 struct nullb_device *dev = nullb->dev;
1410
1411 ida_simple_remove(&nullb_indexes, nullb->index);
1412
1413 list_del_init(&nullb->list);
1414
1415 del_gendisk(nullb->disk);
1416
1417 if (test_bit(NULLB_DEV_FL_THROTTLED, &nullb->dev->flags)) {
1418 hrtimer_cancel(&nullb->bw_timer);
1419 atomic_long_set(&nullb->cur_bytes, LONG_MAX);
1420 null_restart_queue_async(nullb);
1421 }
1422
1423 blk_cleanup_queue(nullb->q);
1424 if (dev->queue_mode == NULL_Q_MQ &&
1425 nullb->tag_set == &nullb->__tag_set)
1426 blk_mq_free_tag_set(nullb->tag_set);
1427 put_disk(nullb->disk);
1428 cleanup_queues(nullb);
1429 if (null_cache_active(nullb))
1430 null_free_device_storage(nullb->dev, true);
1431 kfree(nullb);
1432 dev->nullb = NULL;
1433 }
1434
null_config_discard(struct nullb * nullb)1435 static void null_config_discard(struct nullb *nullb)
1436 {
1437 if (nullb->dev->discard == false)
1438 return;
1439 nullb->q->limits.discard_granularity = nullb->dev->blocksize;
1440 nullb->q->limits.discard_alignment = nullb->dev->blocksize;
1441 blk_queue_max_discard_sectors(nullb->q, UINT_MAX >> 9);
1442 blk_queue_flag_set(QUEUE_FLAG_DISCARD, nullb->q);
1443 }
1444
1445 static const struct block_device_operations null_ops = {
1446 .owner = THIS_MODULE,
1447 .report_zones = null_report_zones,
1448 };
1449
null_init_queue(struct nullb * nullb,struct nullb_queue * nq)1450 static void null_init_queue(struct nullb *nullb, struct nullb_queue *nq)
1451 {
1452 BUG_ON(!nullb);
1453 BUG_ON(!nq);
1454
1455 init_waitqueue_head(&nq->wait);
1456 nq->queue_depth = nullb->queue_depth;
1457 nq->dev = nullb->dev;
1458 }
1459
null_init_queues(struct nullb * nullb)1460 static void null_init_queues(struct nullb *nullb)
1461 {
1462 struct request_queue *q = nullb->q;
1463 struct blk_mq_hw_ctx *hctx;
1464 struct nullb_queue *nq;
1465 int i;
1466
1467 queue_for_each_hw_ctx(q, hctx, i) {
1468 if (!hctx->nr_ctx || !hctx->tags)
1469 continue;
1470 nq = &nullb->queues[i];
1471 hctx->driver_data = nq;
1472 null_init_queue(nullb, nq);
1473 nullb->nr_queues++;
1474 }
1475 }
1476
setup_commands(struct nullb_queue * nq)1477 static int setup_commands(struct nullb_queue *nq)
1478 {
1479 struct nullb_cmd *cmd;
1480 int i, tag_size;
1481
1482 nq->cmds = kcalloc(nq->queue_depth, sizeof(*cmd), GFP_KERNEL);
1483 if (!nq->cmds)
1484 return -ENOMEM;
1485
1486 tag_size = ALIGN(nq->queue_depth, BITS_PER_LONG) / BITS_PER_LONG;
1487 nq->tag_map = kcalloc(tag_size, sizeof(unsigned long), GFP_KERNEL);
1488 if (!nq->tag_map) {
1489 kfree(nq->cmds);
1490 return -ENOMEM;
1491 }
1492
1493 for (i = 0; i < nq->queue_depth; i++) {
1494 cmd = &nq->cmds[i];
1495 INIT_LIST_HEAD(&cmd->list);
1496 cmd->ll_list.next = NULL;
1497 cmd->tag = -1U;
1498 }
1499
1500 return 0;
1501 }
1502
setup_queues(struct nullb * nullb)1503 static int setup_queues(struct nullb *nullb)
1504 {
1505 nullb->queues = kcalloc(nullb->dev->submit_queues,
1506 sizeof(struct nullb_queue),
1507 GFP_KERNEL);
1508 if (!nullb->queues)
1509 return -ENOMEM;
1510
1511 nullb->queue_depth = nullb->dev->hw_queue_depth;
1512
1513 return 0;
1514 }
1515
init_driver_queues(struct nullb * nullb)1516 static int init_driver_queues(struct nullb *nullb)
1517 {
1518 struct nullb_queue *nq;
1519 int i, ret = 0;
1520
1521 for (i = 0; i < nullb->dev->submit_queues; i++) {
1522 nq = &nullb->queues[i];
1523
1524 null_init_queue(nullb, nq);
1525
1526 ret = setup_commands(nq);
1527 if (ret)
1528 return ret;
1529 nullb->nr_queues++;
1530 }
1531 return 0;
1532 }
1533
null_gendisk_register(struct nullb * nullb)1534 static int null_gendisk_register(struct nullb *nullb)
1535 {
1536 sector_t size = ((sector_t)nullb->dev->size * SZ_1M) >> SECTOR_SHIFT;
1537 struct gendisk *disk;
1538
1539 disk = nullb->disk = alloc_disk_node(1, nullb->dev->home_node);
1540 if (!disk)
1541 return -ENOMEM;
1542 set_capacity(disk, size);
1543
1544 disk->flags |= GENHD_FL_EXT_DEVT | GENHD_FL_SUPPRESS_PARTITION_INFO;
1545 disk->major = null_major;
1546 disk->first_minor = nullb->index;
1547 disk->fops = &null_ops;
1548 disk->private_data = nullb;
1549 disk->queue = nullb->q;
1550 strncpy(disk->disk_name, nullb->disk_name, DISK_NAME_LEN);
1551
1552 #ifdef CONFIG_BLK_DEV_ZONED
1553 if (nullb->dev->zoned) {
1554 if (queue_is_mq(nullb->q)) {
1555 int ret = blk_revalidate_disk_zones(disk);
1556 if (ret)
1557 return ret;
1558 } else {
1559 blk_queue_chunk_sectors(nullb->q,
1560 nullb->dev->zone_size_sects);
1561 nullb->q->nr_zones = blkdev_nr_zones(disk);
1562 }
1563 }
1564 #endif
1565
1566 add_disk(disk);
1567 return 0;
1568 }
1569
null_init_tag_set(struct nullb * nullb,struct blk_mq_tag_set * set)1570 static int null_init_tag_set(struct nullb *nullb, struct blk_mq_tag_set *set)
1571 {
1572 set->ops = &null_mq_ops;
1573 set->nr_hw_queues = nullb ? nullb->dev->submit_queues :
1574 g_submit_queues;
1575 set->queue_depth = nullb ? nullb->dev->hw_queue_depth :
1576 g_hw_queue_depth;
1577 set->numa_node = nullb ? nullb->dev->home_node : g_home_node;
1578 set->cmd_size = sizeof(struct nullb_cmd);
1579 set->flags = BLK_MQ_F_SHOULD_MERGE;
1580 if (g_no_sched)
1581 set->flags |= BLK_MQ_F_NO_SCHED;
1582 set->driver_data = NULL;
1583
1584 if ((nullb && nullb->dev->blocking) || g_blocking)
1585 set->flags |= BLK_MQ_F_BLOCKING;
1586
1587 return blk_mq_alloc_tag_set(set);
1588 }
1589
null_validate_conf(struct nullb_device * dev)1590 static int null_validate_conf(struct nullb_device *dev)
1591 {
1592 dev->blocksize = round_down(dev->blocksize, 512);
1593 dev->blocksize = clamp_t(unsigned int, dev->blocksize, 512, 4096);
1594
1595 if (dev->queue_mode == NULL_Q_MQ && dev->use_per_node_hctx) {
1596 if (dev->submit_queues != nr_online_nodes)
1597 dev->submit_queues = nr_online_nodes;
1598 } else if (dev->submit_queues > nr_cpu_ids)
1599 dev->submit_queues = nr_cpu_ids;
1600 else if (dev->submit_queues == 0)
1601 dev->submit_queues = 1;
1602
1603 dev->queue_mode = min_t(unsigned int, dev->queue_mode, NULL_Q_MQ);
1604 dev->irqmode = min_t(unsigned int, dev->irqmode, NULL_IRQ_TIMER);
1605
1606 /* Do memory allocation, so set blocking */
1607 if (dev->memory_backed)
1608 dev->blocking = true;
1609 else /* cache is meaningless */
1610 dev->cache_size = 0;
1611 dev->cache_size = min_t(unsigned long, ULONG_MAX / 1024 / 1024,
1612 dev->cache_size);
1613 dev->mbps = min_t(unsigned int, 1024 * 40, dev->mbps);
1614 /* can not stop a queue */
1615 if (dev->queue_mode == NULL_Q_BIO)
1616 dev->mbps = 0;
1617
1618 if (dev->zoned &&
1619 (!dev->zone_size || !is_power_of_2(dev->zone_size))) {
1620 pr_err("zone_size must be power-of-two\n");
1621 return -EINVAL;
1622 }
1623
1624 return 0;
1625 }
1626
1627 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
__null_setup_fault(struct fault_attr * attr,char * str)1628 static bool __null_setup_fault(struct fault_attr *attr, char *str)
1629 {
1630 if (!str[0])
1631 return true;
1632
1633 if (!setup_fault_attr(attr, str))
1634 return false;
1635
1636 attr->verbose = 0;
1637 return true;
1638 }
1639 #endif
1640
null_setup_fault(void)1641 static bool null_setup_fault(void)
1642 {
1643 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
1644 if (!__null_setup_fault(&null_timeout_attr, g_timeout_str))
1645 return false;
1646 if (!__null_setup_fault(&null_requeue_attr, g_requeue_str))
1647 return false;
1648 #endif
1649 return true;
1650 }
1651
null_add_dev(struct nullb_device * dev)1652 static int null_add_dev(struct nullb_device *dev)
1653 {
1654 struct nullb *nullb;
1655 int rv;
1656
1657 rv = null_validate_conf(dev);
1658 if (rv)
1659 return rv;
1660
1661 nullb = kzalloc_node(sizeof(*nullb), GFP_KERNEL, dev->home_node);
1662 if (!nullb) {
1663 rv = -ENOMEM;
1664 goto out;
1665 }
1666 nullb->dev = dev;
1667 dev->nullb = nullb;
1668
1669 spin_lock_init(&nullb->lock);
1670
1671 rv = setup_queues(nullb);
1672 if (rv)
1673 goto out_free_nullb;
1674
1675 if (dev->queue_mode == NULL_Q_MQ) {
1676 if (shared_tags) {
1677 nullb->tag_set = &tag_set;
1678 rv = 0;
1679 } else {
1680 nullb->tag_set = &nullb->__tag_set;
1681 rv = null_init_tag_set(nullb, nullb->tag_set);
1682 }
1683
1684 if (rv)
1685 goto out_cleanup_queues;
1686
1687 if (!null_setup_fault())
1688 goto out_cleanup_queues;
1689
1690 nullb->tag_set->timeout = 5 * HZ;
1691 nullb->q = blk_mq_init_queue(nullb->tag_set);
1692 if (IS_ERR(nullb->q)) {
1693 rv = -ENOMEM;
1694 goto out_cleanup_tags;
1695 }
1696 null_init_queues(nullb);
1697 } else if (dev->queue_mode == NULL_Q_BIO) {
1698 nullb->q = blk_alloc_queue_node(GFP_KERNEL, dev->home_node);
1699 if (!nullb->q) {
1700 rv = -ENOMEM;
1701 goto out_cleanup_queues;
1702 }
1703 blk_queue_make_request(nullb->q, null_queue_bio);
1704 rv = init_driver_queues(nullb);
1705 if (rv)
1706 goto out_cleanup_blk_queue;
1707 }
1708
1709 if (dev->mbps) {
1710 set_bit(NULLB_DEV_FL_THROTTLED, &dev->flags);
1711 nullb_setup_bwtimer(nullb);
1712 }
1713
1714 if (dev->cache_size > 0) {
1715 set_bit(NULLB_DEV_FL_CACHE, &nullb->dev->flags);
1716 blk_queue_write_cache(nullb->q, true, true);
1717 }
1718
1719 if (dev->zoned) {
1720 rv = null_zone_init(dev);
1721 if (rv)
1722 goto out_cleanup_blk_queue;
1723
1724 nullb->q->limits.zoned = BLK_ZONED_HM;
1725 blk_queue_flag_set(QUEUE_FLAG_ZONE_RESETALL, nullb->q);
1726 blk_queue_required_elevator_features(nullb->q,
1727 ELEVATOR_F_ZBD_SEQ_WRITE);
1728 }
1729
1730 nullb->q->queuedata = nullb;
1731 blk_queue_flag_set(QUEUE_FLAG_NONROT, nullb->q);
1732 blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, nullb->q);
1733
1734 mutex_lock(&lock);
1735 nullb->index = ida_simple_get(&nullb_indexes, 0, 0, GFP_KERNEL);
1736 dev->index = nullb->index;
1737 mutex_unlock(&lock);
1738
1739 blk_queue_logical_block_size(nullb->q, dev->blocksize);
1740 blk_queue_physical_block_size(nullb->q, dev->blocksize);
1741
1742 null_config_discard(nullb);
1743
1744 sprintf(nullb->disk_name, "nullb%d", nullb->index);
1745
1746 rv = null_gendisk_register(nullb);
1747 if (rv)
1748 goto out_cleanup_zone;
1749
1750 mutex_lock(&lock);
1751 list_add_tail(&nullb->list, &nullb_list);
1752 mutex_unlock(&lock);
1753
1754 return 0;
1755 out_cleanup_zone:
1756 if (dev->zoned)
1757 null_zone_exit(dev);
1758 out_cleanup_blk_queue:
1759 blk_cleanup_queue(nullb->q);
1760 out_cleanup_tags:
1761 if (dev->queue_mode == NULL_Q_MQ && nullb->tag_set == &nullb->__tag_set)
1762 blk_mq_free_tag_set(nullb->tag_set);
1763 out_cleanup_queues:
1764 cleanup_queues(nullb);
1765 out_free_nullb:
1766 kfree(nullb);
1767 out:
1768 return rv;
1769 }
1770
null_init(void)1771 static int __init null_init(void)
1772 {
1773 int ret = 0;
1774 unsigned int i;
1775 struct nullb *nullb;
1776 struct nullb_device *dev;
1777
1778 if (g_bs > PAGE_SIZE) {
1779 pr_warn("invalid block size\n");
1780 pr_warn("defaults block size to %lu\n", PAGE_SIZE);
1781 g_bs = PAGE_SIZE;
1782 }
1783
1784 if (g_home_node != NUMA_NO_NODE && g_home_node >= nr_online_nodes) {
1785 pr_err("invalid home_node value\n");
1786 g_home_node = NUMA_NO_NODE;
1787 }
1788
1789 if (g_queue_mode == NULL_Q_RQ) {
1790 pr_err("legacy IO path no longer available\n");
1791 return -EINVAL;
1792 }
1793 if (g_queue_mode == NULL_Q_MQ && g_use_per_node_hctx) {
1794 if (g_submit_queues != nr_online_nodes) {
1795 pr_warn("submit_queues param is set to %u.\n",
1796 nr_online_nodes);
1797 g_submit_queues = nr_online_nodes;
1798 }
1799 } else if (g_submit_queues > nr_cpu_ids)
1800 g_submit_queues = nr_cpu_ids;
1801 else if (g_submit_queues <= 0)
1802 g_submit_queues = 1;
1803
1804 if (g_queue_mode == NULL_Q_MQ && shared_tags) {
1805 ret = null_init_tag_set(NULL, &tag_set);
1806 if (ret)
1807 return ret;
1808 }
1809
1810 config_group_init(&nullb_subsys.su_group);
1811 mutex_init(&nullb_subsys.su_mutex);
1812
1813 ret = configfs_register_subsystem(&nullb_subsys);
1814 if (ret)
1815 goto err_tagset;
1816
1817 mutex_init(&lock);
1818
1819 null_major = register_blkdev(0, "nullb");
1820 if (null_major < 0) {
1821 ret = null_major;
1822 goto err_conf;
1823 }
1824
1825 for (i = 0; i < nr_devices; i++) {
1826 dev = null_alloc_dev();
1827 if (!dev) {
1828 ret = -ENOMEM;
1829 goto err_dev;
1830 }
1831 ret = null_add_dev(dev);
1832 if (ret) {
1833 null_free_dev(dev);
1834 goto err_dev;
1835 }
1836 }
1837
1838 pr_info("module loaded\n");
1839 return 0;
1840
1841 err_dev:
1842 while (!list_empty(&nullb_list)) {
1843 nullb = list_entry(nullb_list.next, struct nullb, list);
1844 dev = nullb->dev;
1845 null_del_dev(nullb);
1846 null_free_dev(dev);
1847 }
1848 unregister_blkdev(null_major, "nullb");
1849 err_conf:
1850 configfs_unregister_subsystem(&nullb_subsys);
1851 err_tagset:
1852 if (g_queue_mode == NULL_Q_MQ && shared_tags)
1853 blk_mq_free_tag_set(&tag_set);
1854 return ret;
1855 }
1856
null_exit(void)1857 static void __exit null_exit(void)
1858 {
1859 struct nullb *nullb;
1860
1861 configfs_unregister_subsystem(&nullb_subsys);
1862
1863 unregister_blkdev(null_major, "nullb");
1864
1865 mutex_lock(&lock);
1866 while (!list_empty(&nullb_list)) {
1867 struct nullb_device *dev;
1868
1869 nullb = list_entry(nullb_list.next, struct nullb, list);
1870 dev = nullb->dev;
1871 null_del_dev(nullb);
1872 null_free_dev(dev);
1873 }
1874 mutex_unlock(&lock);
1875
1876 if (g_queue_mode == NULL_Q_MQ && shared_tags)
1877 blk_mq_free_tag_set(&tag_set);
1878 }
1879
1880 module_init(null_init);
1881 module_exit(null_exit);
1882
1883 MODULE_AUTHOR("Jens Axboe <axboe@kernel.dk>");
1884 MODULE_LICENSE("GPL");
1885