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Merge tag 'hwmon-for-v6.13-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git...
[linux.git] / drivers / block / null_blk / main.c
blob3c3d8d200abba52c46754c21e6b9a3a3777fa005
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 #undef pr_fmt
15 #define pr_fmt(fmt) "null_blk: " fmt
16
17 #define FREE_BATCH 16
18
19 #define TICKS_PER_SEC 50ULL
20 #define TIMER_INTERVAL (NSEC_PER_SEC / TICKS_PER_SEC)
21
22 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
23 static DECLARE_FAULT_ATTR(null_timeout_attr);
24 static DECLARE_FAULT_ATTR(null_requeue_attr);
25 static DECLARE_FAULT_ATTR(null_init_hctx_attr);
26 #endif
27
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 static bool g_virt_boundary;
81 module_param_named(virt_boundary, g_virt_boundary, bool, 0444);
82 MODULE_PARM_DESC(virt_boundary, "Require a virtual boundary for the device. Default: False");
83
84 static int g_no_sched;
85 module_param_named(no_sched, g_no_sched, int, 0444);
86 MODULE_PARM_DESC(no_sched, "No io scheduler");
87
88 static int g_submit_queues = 1;
89 module_param_named(submit_queues, g_submit_queues, int, 0444);
90 MODULE_PARM_DESC(submit_queues, "Number of submission queues");
91
92 static int g_poll_queues = 1;
93 module_param_named(poll_queues, g_poll_queues, int, 0444);
94 MODULE_PARM_DESC(poll_queues, "Number of IOPOLL submission queues");
95
96 static int g_home_node = NUMA_NO_NODE;
97 module_param_named(home_node, g_home_node, int, 0444);
98 MODULE_PARM_DESC(home_node, "Home node for the device");
99
100 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
101 /*
102 * For more details about fault injection, please refer to
103 * Documentation/fault-injection/fault-injection.rst.
104 */
105 static char g_timeout_str[80];
106 module_param_string(timeout, g_timeout_str, sizeof(g_timeout_str), 0444);
107 MODULE_PARM_DESC(timeout, "Fault injection. timeout=<interval>,<probability>,<space>,<times>");
108
109 static char g_requeue_str[80];
110 module_param_string(requeue, g_requeue_str, sizeof(g_requeue_str), 0444);
111 MODULE_PARM_DESC(requeue, "Fault injection. requeue=<interval>,<probability>,<space>,<times>");
112
113 static char g_init_hctx_str[80];
114 module_param_string(init_hctx, g_init_hctx_str, sizeof(g_init_hctx_str), 0444);
115 MODULE_PARM_DESC(init_hctx, "Fault injection to fail hctx init. init_hctx=<interval>,<probability>,<space>,<times>");
116 #endif
117
118 /*
119 * Historic queue modes.
120 *
121 * These days nothing but NULL_Q_MQ is actually supported, but we keep it the
122 * enum for error reporting.
123 */
124 enum {
125 NULL_Q_BIO = 0,
126 NULL_Q_RQ = 1,
127 NULL_Q_MQ = 2,
128 };
129
130 static int g_queue_mode = NULL_Q_MQ;
131
132 static int null_param_store_val(const char *str, int *val, int min, int max)
133 {
134 int ret, new_val;
135
136 ret = kstrtoint(str, 10, &new_val);
137 if (ret)
138 return -EINVAL;
139
140 if (new_val < min || new_val > max)
141 return -EINVAL;
142
143 *val = new_val;
144 return 0;
145 }
146
147 static int null_set_queue_mode(const char *str, const struct kernel_param *kp)
148 {
149 return null_param_store_val(str, &g_queue_mode, NULL_Q_BIO, NULL_Q_MQ);
150 }
151
152 static const struct kernel_param_ops null_queue_mode_param_ops = {
153 .set = null_set_queue_mode,
154 .get = param_get_int,
155 };
156
157 device_param_cb(queue_mode, &null_queue_mode_param_ops, &g_queue_mode, 0444);
158 MODULE_PARM_DESC(queue_mode, "Block interface to use (0=bio,1=rq,2=multiqueue)");
159
160 static int g_gb = 250;
161 module_param_named(gb, g_gb, int, 0444);
162 MODULE_PARM_DESC(gb, "Size in GB");
163
164 static int g_bs = 512;
165 module_param_named(bs, g_bs, int, 0444);
166 MODULE_PARM_DESC(bs, "Block size (in bytes)");
167
168 static int g_max_sectors;
169 module_param_named(max_sectors, g_max_sectors, int, 0444);
170 MODULE_PARM_DESC(max_sectors, "Maximum size of a command (in 512B sectors)");
171
172 static unsigned int nr_devices = 1;
173 module_param(nr_devices, uint, 0444);
174 MODULE_PARM_DESC(nr_devices, "Number of devices to register");
175
176 static bool g_blocking;
177 module_param_named(blocking, g_blocking, bool, 0444);
178 MODULE_PARM_DESC(blocking, "Register as a blocking blk-mq driver device");
179
180 static bool g_shared_tags;
181 module_param_named(shared_tags, g_shared_tags, bool, 0444);
182 MODULE_PARM_DESC(shared_tags, "Share tag set between devices for blk-mq");
183
184 static bool g_shared_tag_bitmap;
185 module_param_named(shared_tag_bitmap, g_shared_tag_bitmap, bool, 0444);
186 MODULE_PARM_DESC(shared_tag_bitmap, "Use shared tag bitmap for all submission queues for blk-mq");
187
188 static int g_irqmode = NULL_IRQ_SOFTIRQ;
189
190 static int null_set_irqmode(const char *str, const struct kernel_param *kp)
191 {
192 return null_param_store_val(str, &g_irqmode, NULL_IRQ_NONE,
193 NULL_IRQ_TIMER);
194 }
195
196 static const struct kernel_param_ops null_irqmode_param_ops = {
197 .set = null_set_irqmode,
198 .get = param_get_int,
199 };
200
201 device_param_cb(irqmode, &null_irqmode_param_ops, &g_irqmode, 0444);
202 MODULE_PARM_DESC(irqmode, "IRQ completion handler. 0-none, 1-softirq, 2-timer");
203
204 static unsigned long g_completion_nsec = 10000;
205 module_param_named(completion_nsec, g_completion_nsec, ulong, 0444);
206 MODULE_PARM_DESC(completion_nsec, "Time in ns to complete a request in hardware. Default: 10,000ns");
207
208 static int g_hw_queue_depth = 64;
209 module_param_named(hw_queue_depth, g_hw_queue_depth, int, 0444);
210 MODULE_PARM_DESC(hw_queue_depth, "Queue depth for each hardware queue. Default: 64");
211
212 static bool g_use_per_node_hctx;
213 module_param_named(use_per_node_hctx, g_use_per_node_hctx, bool, 0444);
214 MODULE_PARM_DESC(use_per_node_hctx, "Use per-node allocation for hardware context queues. Default: false");
215
216 static bool g_memory_backed;
217 module_param_named(memory_backed, g_memory_backed, bool, 0444);
218 MODULE_PARM_DESC(memory_backed, "Create a memory-backed block device. Default: false");
219
220 static bool g_discard;
221 module_param_named(discard, g_discard, bool, 0444);
222 MODULE_PARM_DESC(discard, "Support discard operations (requires memory-backed null_blk device). Default: false");
223
224 static unsigned long g_cache_size;
225 module_param_named(cache_size, g_cache_size, ulong, 0444);
226 MODULE_PARM_DESC(mbps, "Cache size in MiB for memory-backed device. Default: 0 (none)");
227
228 static bool g_fua = true;
229 module_param_named(fua, g_fua, bool, 0444);
230 MODULE_PARM_DESC(fua, "Enable/disable FUA support when cache_size is used. Default: true");
231
232 static unsigned int g_mbps;
233 module_param_named(mbps, g_mbps, uint, 0444);
234 MODULE_PARM_DESC(mbps, "Limit maximum bandwidth (in MiB/s). Default: 0 (no limit)");
235
236 static bool g_zoned;
237 module_param_named(zoned, g_zoned, bool, S_IRUGO);
238 MODULE_PARM_DESC(zoned, "Make device as a host-managed zoned block device. Default: false");
239
240 static unsigned long g_zone_size = 256;
241 module_param_named(zone_size, g_zone_size, ulong, S_IRUGO);
242 MODULE_PARM_DESC(zone_size, "Zone size in MB when block device is zoned. Must be power-of-two: Default: 256");
243
244 static unsigned long g_zone_capacity;
245 module_param_named(zone_capacity, g_zone_capacity, ulong, 0444);
246 MODULE_PARM_DESC(zone_capacity, "Zone capacity in MB when block device is zoned. Can be less than or equal to zone size. Default: Zone size");
247
248 static unsigned int g_zone_nr_conv;
249 module_param_named(zone_nr_conv, g_zone_nr_conv, uint, 0444);
250 MODULE_PARM_DESC(zone_nr_conv, "Number of conventional zones when block device is zoned. Default: 0");
251
252 static unsigned int g_zone_max_open;
253 module_param_named(zone_max_open, g_zone_max_open, uint, 0444);
254 MODULE_PARM_DESC(zone_max_open, "Maximum number of open zones when block device is zoned. Default: 0 (no limit)");
255
256 static unsigned int g_zone_max_active;
257 module_param_named(zone_max_active, g_zone_max_active, uint, 0444);
258 MODULE_PARM_DESC(zone_max_active, "Maximum number of active zones when block device is zoned. Default: 0 (no limit)");
259
260 static int g_zone_append_max_sectors = INT_MAX;
261 module_param_named(zone_append_max_sectors, g_zone_append_max_sectors, int, 0444);
262 MODULE_PARM_DESC(zone_append_max_sectors,
263 "Maximum size of a zone append command (in 512B sectors). Specify 0 for zone append emulation");
264
265 static bool g_zone_full;
266 module_param_named(zone_full, g_zone_full, bool, S_IRUGO);
267 MODULE_PARM_DESC(zone_full, "Initialize the sequential write required zones of a zoned device to be full. Default: false");
268
269 static struct nullb_device *null_alloc_dev(void);
270 static void null_free_dev(struct nullb_device *dev);
271 static void null_del_dev(struct nullb *nullb);
272 static int null_add_dev(struct nullb_device *dev);
273 static struct nullb *null_find_dev_by_name(const char *name);
274 static void null_free_device_storage(struct nullb_device *dev, bool is_cache);
275
276 static inline struct nullb_device *to_nullb_device(struct config_item *item)
277 {
278 return item ? container_of(to_config_group(item), struct nullb_device, group) : NULL;
279 }
280
281 static inline ssize_t nullb_device_uint_attr_show(unsigned int val, char *page)
282 {
283 return snprintf(page, PAGE_SIZE, "%u\n", val);
284 }
285
286 static inline ssize_t nullb_device_ulong_attr_show(unsigned long val,
287 char *page)
288 {
289 return snprintf(page, PAGE_SIZE, "%lu\n", val);
290 }
291
292 static inline ssize_t nullb_device_bool_attr_show(bool val, char *page)
293 {
294 return snprintf(page, PAGE_SIZE, "%u\n", val);
295 }
296
297 static ssize_t nullb_device_uint_attr_store(unsigned int *val,
298 const char *page, size_t count)
299 {
300 unsigned int tmp;
301 int result;
302
303 result = kstrtouint(page, 0, &tmp);
304 if (result < 0)
305 return result;
306
307 *val = tmp;
308 return count;
309 }
310
311 static ssize_t nullb_device_ulong_attr_store(unsigned long *val,
312 const char *page, size_t count)
313 {
314 int result;
315 unsigned long tmp;
316
317 result = kstrtoul(page, 0, &tmp);
318 if (result < 0)
319 return result;
320
321 *val = tmp;
322 return count;
323 }
324
325 static ssize_t nullb_device_bool_attr_store(bool *val, const char *page,
326 size_t count)
327 {
328 bool tmp;
329 int result;
330
331 result = kstrtobool(page, &tmp);
332 if (result < 0)
333 return result;
334
335 *val = tmp;
336 return count;
337 }
338
339 /* The following macro should only be used with TYPE = {uint, ulong, bool}. */
340 #define NULLB_DEVICE_ATTR(NAME, TYPE, APPLY) \
341 static ssize_t \
342 nullb_device_##NAME##_show(struct config_item *item, char *page) \
343 { \
344 return nullb_device_##TYPE##_attr_show( \
345 to_nullb_device(item)->NAME, page); \
346 } \
347 static ssize_t \
348 nullb_device_##NAME##_store(struct config_item *item, const char *page, \
349 size_t count) \
350 { \
351 int (*apply_fn)(struct nullb_device *dev, TYPE new_value) = APPLY;\
352 struct nullb_device *dev = to_nullb_device(item); \
353 TYPE new_value = 0; \
354 int ret; \
355 \
356 ret = nullb_device_##TYPE##_attr_store(&new_value, page, count);\
357 if (ret < 0) \
358 return ret; \
359 if (apply_fn) \
360 ret = apply_fn(dev, new_value); \
361 else if (test_bit(NULLB_DEV_FL_CONFIGURED, &dev->flags)) \
362 ret = -EBUSY; \
363 if (ret < 0) \
364 return ret; \
365 dev->NAME = new_value; \
366 return count; \
367 } \
368 CONFIGFS_ATTR(nullb_device_, NAME);
369
370 static int nullb_update_nr_hw_queues(struct nullb_device *dev,
371 unsigned int submit_queues,
372 unsigned int poll_queues)
373
374 {
375 struct blk_mq_tag_set *set;
376 int ret, nr_hw_queues;
377
378 if (!dev->nullb)
379 return 0;
380
381 /*
382 * Make sure at least one submit queue exists.
383 */
384 if (!submit_queues)
385 return -EINVAL;
386
387 /*
388 * Make sure that null_init_hctx() does not access nullb->queues[] past
389 * the end of that array.
390 */
391 if (submit_queues > nr_cpu_ids || poll_queues > g_poll_queues)
392 return -EINVAL;
393
394 /*
395 * Keep previous and new queue numbers in nullb_device for reference in
396 * the call back function null_map_queues().
397 */
398 dev->prev_submit_queues = dev->submit_queues;
399 dev->prev_poll_queues = dev->poll_queues;
400 dev->submit_queues = submit_queues;
401 dev->poll_queues = poll_queues;
402
403 set = dev->nullb->tag_set;
404 nr_hw_queues = submit_queues + poll_queues;
405 blk_mq_update_nr_hw_queues(set, nr_hw_queues);
406 ret = set->nr_hw_queues == nr_hw_queues ? 0 : -ENOMEM;
407
408 if (ret) {
409 /* on error, revert the queue numbers */
410 dev->submit_queues = dev->prev_submit_queues;
411 dev->poll_queues = dev->prev_poll_queues;
412 }
413
414 return ret;
415 }
416
417 static int nullb_apply_submit_queues(struct nullb_device *dev,
418 unsigned int submit_queues)
419 {
420 int ret;
421
422 mutex_lock(&lock);
423 ret = nullb_update_nr_hw_queues(dev, submit_queues, dev->poll_queues);
424 mutex_unlock(&lock);
425
426 return ret;
427 }
428
429 static int nullb_apply_poll_queues(struct nullb_device *dev,
430 unsigned int poll_queues)
431 {
432 int ret;
433
434 mutex_lock(&lock);
435 ret = nullb_update_nr_hw_queues(dev, dev->submit_queues, poll_queues);
436 mutex_unlock(&lock);
437
438 return ret;
439 }
440
441 NULLB_DEVICE_ATTR(size, ulong, NULL);
442 NULLB_DEVICE_ATTR(completion_nsec, ulong, NULL);
443 NULLB_DEVICE_ATTR(submit_queues, uint, nullb_apply_submit_queues);
444 NULLB_DEVICE_ATTR(poll_queues, uint, nullb_apply_poll_queues);
445 NULLB_DEVICE_ATTR(home_node, uint, NULL);
446 NULLB_DEVICE_ATTR(queue_mode, uint, NULL);
447 NULLB_DEVICE_ATTR(blocksize, uint, NULL);
448 NULLB_DEVICE_ATTR(max_sectors, uint, NULL);
449 NULLB_DEVICE_ATTR(irqmode, uint, NULL);
450 NULLB_DEVICE_ATTR(hw_queue_depth, uint, NULL);
451 NULLB_DEVICE_ATTR(index, uint, NULL);
452 NULLB_DEVICE_ATTR(blocking, bool, NULL);
453 NULLB_DEVICE_ATTR(use_per_node_hctx, bool, NULL);
454 NULLB_DEVICE_ATTR(memory_backed, bool, NULL);
455 NULLB_DEVICE_ATTR(discard, bool, NULL);
456 NULLB_DEVICE_ATTR(mbps, uint, NULL);
457 NULLB_DEVICE_ATTR(cache_size, ulong, NULL);
458 NULLB_DEVICE_ATTR(zoned, bool, NULL);
459 NULLB_DEVICE_ATTR(zone_size, ulong, NULL);
460 NULLB_DEVICE_ATTR(zone_capacity, ulong, NULL);
461 NULLB_DEVICE_ATTR(zone_nr_conv, uint, NULL);
462 NULLB_DEVICE_ATTR(zone_max_open, uint, NULL);
463 NULLB_DEVICE_ATTR(zone_max_active, uint, NULL);
464 NULLB_DEVICE_ATTR(zone_append_max_sectors, uint, NULL);
465 NULLB_DEVICE_ATTR(zone_full, bool, NULL);
466 NULLB_DEVICE_ATTR(virt_boundary, bool, NULL);
467 NULLB_DEVICE_ATTR(no_sched, bool, NULL);
468 NULLB_DEVICE_ATTR(shared_tags, bool, NULL);
469 NULLB_DEVICE_ATTR(shared_tag_bitmap, bool, NULL);
470 NULLB_DEVICE_ATTR(fua, bool, NULL);
471
472 static ssize_t nullb_device_power_show(struct config_item *item, char *page)
473 {
474 return nullb_device_bool_attr_show(to_nullb_device(item)->power, page);
475 }
476
477 static ssize_t nullb_device_power_store(struct config_item *item,
478 const char *page, size_t count)
479 {
480 struct nullb_device *dev = to_nullb_device(item);
481 bool newp = false;
482 ssize_t ret;
483
484 ret = nullb_device_bool_attr_store(&newp, page, count);
485 if (ret < 0)
486 return ret;
487
488 ret = count;
489 mutex_lock(&lock);
490 if (!dev->power && newp) {
491 if (test_and_set_bit(NULLB_DEV_FL_UP, &dev->flags))
492 goto out;
493
494 ret = null_add_dev(dev);
495 if (ret) {
496 clear_bit(NULLB_DEV_FL_UP, &dev->flags);
497 goto out;
498 }
499
500 set_bit(NULLB_DEV_FL_CONFIGURED, &dev->flags);
501 dev->power = newp;
502 ret = count;
503 } else if (dev->power && !newp) {
504 if (test_and_clear_bit(NULLB_DEV_FL_UP, &dev->flags)) {
505 dev->power = newp;
506 null_del_dev(dev->nullb);
507 }
508 clear_bit(NULLB_DEV_FL_CONFIGURED, &dev->flags);
509 }
510
511 out:
512 mutex_unlock(&lock);
513 return ret;
514 }
515
516 CONFIGFS_ATTR(nullb_device_, power);
517
518 static ssize_t nullb_device_badblocks_show(struct config_item *item, char *page)
519 {
520 struct nullb_device *t_dev = to_nullb_device(item);
521
522 return badblocks_show(&t_dev->badblocks, page, 0);
523 }
524
525 static ssize_t nullb_device_badblocks_store(struct config_item *item,
526 const char *page, size_t count)
527 {
528 struct nullb_device *t_dev = to_nullb_device(item);
529 char *orig, *buf, *tmp;
530 u64 start, end;
531 int ret;
532
533 orig = kstrndup(page, count, GFP_KERNEL);
534 if (!orig)
535 return -ENOMEM;
536
537 buf = strstrip(orig);
538
539 ret = -EINVAL;
540 if (buf[0] != '+' && buf[0] != '-')
541 goto out;
542 tmp = strchr(&buf[1], '-');
543 if (!tmp)
544 goto out;
545 *tmp = '\0';
546 ret = kstrtoull(buf + 1, 0, &start);
547 if (ret)
548 goto out;
549 ret = kstrtoull(tmp + 1, 0, &end);
550 if (ret)
551 goto out;
552 ret = -EINVAL;
553 if (start > end)
554 goto out;
555 /* enable badblocks */
556 cmpxchg(&t_dev->badblocks.shift, -1, 0);
557 if (buf[0] == '+')
558 ret = badblocks_set(&t_dev->badblocks, start,
559 end - start + 1, 1);
560 else
561 ret = badblocks_clear(&t_dev->badblocks, start,
562 end - start + 1);
563 if (ret == 0)
564 ret = count;
565 out:
566 kfree(orig);
567 return ret;
568 }
569 CONFIGFS_ATTR(nullb_device_, badblocks);
570
571 static ssize_t nullb_device_zone_readonly_store(struct config_item *item,
572 const char *page, size_t count)
573 {
574 struct nullb_device *dev = to_nullb_device(item);
575
576 return zone_cond_store(dev, page, count, BLK_ZONE_COND_READONLY);
577 }
578 CONFIGFS_ATTR_WO(nullb_device_, zone_readonly);
579
580 static ssize_t nullb_device_zone_offline_store(struct config_item *item,
581 const char *page, size_t count)
582 {
583 struct nullb_device *dev = to_nullb_device(item);
584
585 return zone_cond_store(dev, page, count, BLK_ZONE_COND_OFFLINE);
586 }
587 CONFIGFS_ATTR_WO(nullb_device_, zone_offline);
588
589 static struct configfs_attribute *nullb_device_attrs[] = {
590 &nullb_device_attr_size,
591 &nullb_device_attr_completion_nsec,
592 &nullb_device_attr_submit_queues,
593 &nullb_device_attr_poll_queues,
594 &nullb_device_attr_home_node,
595 &nullb_device_attr_queue_mode,
596 &nullb_device_attr_blocksize,
597 &nullb_device_attr_max_sectors,
598 &nullb_device_attr_irqmode,
599 &nullb_device_attr_hw_queue_depth,
600 &nullb_device_attr_index,
601 &nullb_device_attr_blocking,
602 &nullb_device_attr_use_per_node_hctx,
603 &nullb_device_attr_power,
604 &nullb_device_attr_memory_backed,
605 &nullb_device_attr_discard,
606 &nullb_device_attr_mbps,
607 &nullb_device_attr_cache_size,
608 &nullb_device_attr_badblocks,
609 &nullb_device_attr_zoned,
610 &nullb_device_attr_zone_size,
611 &nullb_device_attr_zone_capacity,
612 &nullb_device_attr_zone_nr_conv,
613 &nullb_device_attr_zone_max_open,
614 &nullb_device_attr_zone_max_active,
615 &nullb_device_attr_zone_append_max_sectors,
616 &nullb_device_attr_zone_readonly,
617 &nullb_device_attr_zone_offline,
618 &nullb_device_attr_zone_full,
619 &nullb_device_attr_virt_boundary,
620 &nullb_device_attr_no_sched,
621 &nullb_device_attr_shared_tags,
622 &nullb_device_attr_shared_tag_bitmap,
623 &nullb_device_attr_fua,
624 NULL,
625 };
626
627 static void nullb_device_release(struct config_item *item)
628 {
629 struct nullb_device *dev = to_nullb_device(item);
630
631 null_free_device_storage(dev, false);
632 null_free_dev(dev);
633 }
634
635 static struct configfs_item_operations nullb_device_ops = {
636 .release = nullb_device_release,
637 };
638
639 static const struct config_item_type nullb_device_type = {
640 .ct_item_ops = &nullb_device_ops,
641 .ct_attrs = nullb_device_attrs,
642 .ct_owner = THIS_MODULE,
643 };
644
645 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
646
647 static void nullb_add_fault_config(struct nullb_device *dev)
648 {
649 fault_config_init(&dev->timeout_config, "timeout_inject");
650 fault_config_init(&dev->requeue_config, "requeue_inject");
651 fault_config_init(&dev->init_hctx_fault_config, "init_hctx_fault_inject");
652
653 configfs_add_default_group(&dev->timeout_config.group, &dev->group);
654 configfs_add_default_group(&dev->requeue_config.group, &dev->group);
655 configfs_add_default_group(&dev->init_hctx_fault_config.group, &dev->group);
656 }
657
658 #else
659
660 static void nullb_add_fault_config(struct nullb_device *dev)
661 {
662 }
663
664 #endif
665
666 static struct
667 config_group *nullb_group_make_group(struct config_group *group, const char *name)
668 {
669 struct nullb_device *dev;
670
671 if (null_find_dev_by_name(name))
672 return ERR_PTR(-EEXIST);
673
674 dev = null_alloc_dev();
675 if (!dev)
676 return ERR_PTR(-ENOMEM);
677
678 config_group_init_type_name(&dev->group, name, &nullb_device_type);
679 nullb_add_fault_config(dev);
680
681 return &dev->group;
682 }
683
684 static void
685 nullb_group_drop_item(struct config_group *group, struct config_item *item)
686 {
687 struct nullb_device *dev = to_nullb_device(item);
688
689 if (test_and_clear_bit(NULLB_DEV_FL_UP, &dev->flags)) {
690 mutex_lock(&lock);
691 dev->power = false;
692 null_del_dev(dev->nullb);
693 mutex_unlock(&lock);
694 }
695
696 config_item_put(item);
697 }
698
699 static ssize_t memb_group_features_show(struct config_item *item, char *page)
700 {
701 return snprintf(page, PAGE_SIZE,
702 "badblocks,blocking,blocksize,cache_size,fua,"
703 "completion_nsec,discard,home_node,hw_queue_depth,"
704 "irqmode,max_sectors,mbps,memory_backed,no_sched,"
705 "poll_queues,power,queue_mode,shared_tag_bitmap,"
706 "shared_tags,size,submit_queues,use_per_node_hctx,"
707 "virt_boundary,zoned,zone_capacity,zone_max_active,"
708 "zone_max_open,zone_nr_conv,zone_offline,zone_readonly,"
709 "zone_size,zone_append_max_sectors,zone_full\n");
710 }
711
712 CONFIGFS_ATTR_RO(memb_group_, features);
713
714 static struct configfs_attribute *nullb_group_attrs[] = {
715 &memb_group_attr_features,
716 NULL,
717 };
718
719 static struct configfs_group_operations nullb_group_ops = {
720 .make_group = nullb_group_make_group,
721 .drop_item = nullb_group_drop_item,
722 };
723
724 static const struct config_item_type nullb_group_type = {
725 .ct_group_ops = &nullb_group_ops,
726 .ct_attrs = nullb_group_attrs,
727 .ct_owner = THIS_MODULE,
728 };
729
730 static struct configfs_subsystem nullb_subsys = {
731 .su_group = {
732 .cg_item = {
733 .ci_namebuf = "nullb",
734 .ci_type = &nullb_group_type,
735 },
736 },
737 };
738
739 static inline int null_cache_active(struct nullb *nullb)
740 {
741 return test_bit(NULLB_DEV_FL_CACHE, &nullb->dev->flags);
742 }
743
744 static struct nullb_device *null_alloc_dev(void)
745 {
746 struct nullb_device *dev;
747
748 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
749 if (!dev)
750 return NULL;
751
752 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
753 dev->timeout_config.attr = null_timeout_attr;
754 dev->requeue_config.attr = null_requeue_attr;
755 dev->init_hctx_fault_config.attr = null_init_hctx_attr;
756 #endif
757
758 INIT_RADIX_TREE(&dev->data, GFP_ATOMIC);
759 INIT_RADIX_TREE(&dev->cache, GFP_ATOMIC);
760 if (badblocks_init(&dev->badblocks, 0)) {
761 kfree(dev);
762 return NULL;
763 }
764
765 dev->size = g_gb * 1024;
766 dev->completion_nsec = g_completion_nsec;
767 dev->submit_queues = g_submit_queues;
768 dev->prev_submit_queues = g_submit_queues;
769 dev->poll_queues = g_poll_queues;
770 dev->prev_poll_queues = g_poll_queues;
771 dev->home_node = g_home_node;
772 dev->queue_mode = g_queue_mode;
773 dev->blocksize = g_bs;
774 dev->max_sectors = g_max_sectors;
775 dev->irqmode = g_irqmode;
776 dev->hw_queue_depth = g_hw_queue_depth;
777 dev->blocking = g_blocking;
778 dev->memory_backed = g_memory_backed;
779 dev->discard = g_discard;
780 dev->cache_size = g_cache_size;
781 dev->mbps = g_mbps;
782 dev->use_per_node_hctx = g_use_per_node_hctx;
783 dev->zoned = g_zoned;
784 dev->zone_size = g_zone_size;
785 dev->zone_capacity = g_zone_capacity;
786 dev->zone_nr_conv = g_zone_nr_conv;
787 dev->zone_max_open = g_zone_max_open;
788 dev->zone_max_active = g_zone_max_active;
789 dev->zone_append_max_sectors = g_zone_append_max_sectors;
790 dev->zone_full = g_zone_full;
791 dev->virt_boundary = g_virt_boundary;
792 dev->no_sched = g_no_sched;
793 dev->shared_tags = g_shared_tags;
794 dev->shared_tag_bitmap = g_shared_tag_bitmap;
795 dev->fua = g_fua;
796
797 return dev;
798 }
799
800 static void null_free_dev(struct nullb_device *dev)
801 {
802 if (!dev)
803 return;
804
805 null_free_zoned_dev(dev);
806 badblocks_exit(&dev->badblocks);
807 kfree(dev);
808 }
809
810 static enum hrtimer_restart null_cmd_timer_expired(struct hrtimer *timer)
811 {
812 struct nullb_cmd *cmd = container_of(timer, struct nullb_cmd, timer);
813
814 blk_mq_end_request(blk_mq_rq_from_pdu(cmd), cmd->error);
815 return HRTIMER_NORESTART;
816 }
817
818 static void null_cmd_end_timer(struct nullb_cmd *cmd)
819 {
820 ktime_t kt = cmd->nq->dev->completion_nsec;
821
822 hrtimer_start(&cmd->timer, kt, HRTIMER_MODE_REL);
823 }
824
825 static void null_complete_rq(struct request *rq)
826 {
827 struct nullb_cmd *cmd = blk_mq_rq_to_pdu(rq);
828
829 blk_mq_end_request(rq, cmd->error);
830 }
831
832 static struct nullb_page *null_alloc_page(void)
833 {
834 struct nullb_page *t_page;
835
836 t_page = kmalloc(sizeof(struct nullb_page), GFP_NOIO);
837 if (!t_page)
838 return NULL;
839
840 t_page->page = alloc_pages(GFP_NOIO, 0);
841 if (!t_page->page) {
842 kfree(t_page);
843 return NULL;
844 }
845
846 memset(t_page->bitmap, 0, sizeof(t_page->bitmap));
847 return t_page;
848 }
849
850 static void null_free_page(struct nullb_page *t_page)
851 {
852 __set_bit(NULLB_PAGE_FREE, t_page->bitmap);
853 if (test_bit(NULLB_PAGE_LOCK, t_page->bitmap))
854 return;
855 __free_page(t_page->page);
856 kfree(t_page);
857 }
858
859 static bool null_page_empty(struct nullb_page *page)
860 {
861 int size = MAP_SZ - 2;
862
863 return find_first_bit(page->bitmap, size) == size;
864 }
865
866 static void null_free_sector(struct nullb *nullb, sector_t sector,
867 bool is_cache)
868 {
869 unsigned int sector_bit;
870 u64 idx;
871 struct nullb_page *t_page, *ret;
872 struct radix_tree_root *root;
873
874 root = is_cache ? &nullb->dev->cache : &nullb->dev->data;
875 idx = sector >> PAGE_SECTORS_SHIFT;
876 sector_bit = (sector & SECTOR_MASK);
877
878 t_page = radix_tree_lookup(root, idx);
879 if (t_page) {
880 __clear_bit(sector_bit, t_page->bitmap);
881
882 if (null_page_empty(t_page)) {
883 ret = radix_tree_delete_item(root, idx, t_page);
884 WARN_ON(ret != t_page);
885 null_free_page(ret);
886 if (is_cache)
887 nullb->dev->curr_cache -= PAGE_SIZE;
888 }
889 }
890 }
891
892 static struct nullb_page *null_radix_tree_insert(struct nullb *nullb, u64 idx,
893 struct nullb_page *t_page, bool is_cache)
894 {
895 struct radix_tree_root *root;
896
897 root = is_cache ? &nullb->dev->cache : &nullb->dev->data;
898
899 if (radix_tree_insert(root, idx, t_page)) {
900 null_free_page(t_page);
901 t_page = radix_tree_lookup(root, idx);
902 WARN_ON(!t_page || t_page->page->index != idx);
903 } else if (is_cache)
904 nullb->dev->curr_cache += PAGE_SIZE;
905
906 return t_page;
907 }
908
909 static void null_free_device_storage(struct nullb_device *dev, bool is_cache)
910 {
911 unsigned long pos = 0;
912 int nr_pages;
913 struct nullb_page *ret, *t_pages[FREE_BATCH];
914 struct radix_tree_root *root;
915
916 root = is_cache ? &dev->cache : &dev->data;
917
918 do {
919 int i;
920
921 nr_pages = radix_tree_gang_lookup(root,
922 (void **)t_pages, pos, FREE_BATCH);
923
924 for (i = 0; i < nr_pages; i++) {
925 pos = t_pages[i]->page->index;
926 ret = radix_tree_delete_item(root, pos, t_pages[i]);
927 WARN_ON(ret != t_pages[i]);
928 null_free_page(ret);
929 }
930
931 pos++;
932 } while (nr_pages == FREE_BATCH);
933
934 if (is_cache)
935 dev->curr_cache = 0;
936 }
937
938 static struct nullb_page *__null_lookup_page(struct nullb *nullb,
939 sector_t sector, bool for_write, bool is_cache)
940 {
941 unsigned int sector_bit;
942 u64 idx;
943 struct nullb_page *t_page;
944 struct radix_tree_root *root;
945
946 idx = sector >> PAGE_SECTORS_SHIFT;
947 sector_bit = (sector & SECTOR_MASK);
948
949 root = is_cache ? &nullb->dev->cache : &nullb->dev->data;
950 t_page = radix_tree_lookup(root, idx);
951 WARN_ON(t_page && t_page->page->index != idx);
952
953 if (t_page && (for_write || test_bit(sector_bit, t_page->bitmap)))
954 return t_page;
955
956 return NULL;
957 }
958
959 static struct nullb_page *null_lookup_page(struct nullb *nullb,
960 sector_t sector, bool for_write, bool ignore_cache)
961 {
962 struct nullb_page *page = NULL;
963
964 if (!ignore_cache)
965 page = __null_lookup_page(nullb, sector, for_write, true);
966 if (page)
967 return page;
968 return __null_lookup_page(nullb, sector, for_write, false);
969 }
970
971 static struct nullb_page *null_insert_page(struct nullb *nullb,
972 sector_t sector, bool ignore_cache)
973 __releases(&nullb->lock)
974 __acquires(&nullb->lock)
975 {
976 u64 idx;
977 struct nullb_page *t_page;
978
979 t_page = null_lookup_page(nullb, sector, true, ignore_cache);
980 if (t_page)
981 return t_page;
982
983 spin_unlock_irq(&nullb->lock);
984
985 t_page = null_alloc_page();
986 if (!t_page)
987 goto out_lock;
988
989 if (radix_tree_preload(GFP_NOIO))
990 goto out_freepage;
991
992 spin_lock_irq(&nullb->lock);
993 idx = sector >> PAGE_SECTORS_SHIFT;
994 t_page->page->index = idx;
995 t_page = null_radix_tree_insert(nullb, idx, t_page, !ignore_cache);
996 radix_tree_preload_end();
997
998 return t_page;
999 out_freepage:
1000 null_free_page(t_page);
1001 out_lock:
1002 spin_lock_irq(&nullb->lock);
1003 return null_lookup_page(nullb, sector, true, ignore_cache);
1004 }
1005
1006 static int null_flush_cache_page(struct nullb *nullb, struct nullb_page *c_page)
1007 {
1008 int i;
1009 unsigned int offset;
1010 u64 idx;
1011 struct nullb_page *t_page, *ret;
1012 void *dst, *src;
1013
1014 idx = c_page->page->index;
1015
1016 t_page = null_insert_page(nullb, idx << PAGE_SECTORS_SHIFT, true);
1017
1018 __clear_bit(NULLB_PAGE_LOCK, c_page->bitmap);
1019 if (test_bit(NULLB_PAGE_FREE, c_page->bitmap)) {
1020 null_free_page(c_page);
1021 if (t_page && null_page_empty(t_page)) {
1022 ret = radix_tree_delete_item(&nullb->dev->data,
1023 idx, t_page);
1024 null_free_page(t_page);
1025 }
1026 return 0;
1027 }
1028
1029 if (!t_page)
1030 return -ENOMEM;
1031
1032 src = kmap_local_page(c_page->page);
1033 dst = kmap_local_page(t_page->page);
1034
1035 for (i = 0; i < PAGE_SECTORS;
1036 i += (nullb->dev->blocksize >> SECTOR_SHIFT)) {
1037 if (test_bit(i, c_page->bitmap)) {
1038 offset = (i << SECTOR_SHIFT);
1039 memcpy(dst + offset, src + offset,
1040 nullb->dev->blocksize);
1041 __set_bit(i, t_page->bitmap);
1042 }
1043 }
1044
1045 kunmap_local(dst);
1046 kunmap_local(src);
1047
1048 ret = radix_tree_delete_item(&nullb->dev->cache, idx, c_page);
1049 null_free_page(ret);
1050 nullb->dev->curr_cache -= PAGE_SIZE;
1051
1052 return 0;
1053 }
1054
1055 static int null_make_cache_space(struct nullb *nullb, unsigned long n)
1056 {
1057 int i, err, nr_pages;
1058 struct nullb_page *c_pages[FREE_BATCH];
1059 unsigned long flushed = 0, one_round;
1060
1061 again:
1062 if ((nullb->dev->cache_size * 1024 * 1024) >
1063 nullb->dev->curr_cache + n || nullb->dev->curr_cache == 0)
1064 return 0;
1065
1066 nr_pages = radix_tree_gang_lookup(&nullb->dev->cache,
1067 (void **)c_pages, nullb->cache_flush_pos, FREE_BATCH);
1068 /*
1069 * nullb_flush_cache_page could unlock before using the c_pages. To
1070 * avoid race, we don't allow page free
1071 */
1072 for (i = 0; i < nr_pages; i++) {
1073 nullb->cache_flush_pos = c_pages[i]->page->index;
1074 /*
1075 * We found the page which is being flushed to disk by other
1076 * threads
1077 */
1078 if (test_bit(NULLB_PAGE_LOCK, c_pages[i]->bitmap))
1079 c_pages[i] = NULL;
1080 else
1081 __set_bit(NULLB_PAGE_LOCK, c_pages[i]->bitmap);
1082 }
1083
1084 one_round = 0;
1085 for (i = 0; i < nr_pages; i++) {
1086 if (c_pages[i] == NULL)
1087 continue;
1088 err = null_flush_cache_page(nullb, c_pages[i]);
1089 if (err)
1090 return err;
1091 one_round++;
1092 }
1093 flushed += one_round << PAGE_SHIFT;
1094
1095 if (n > flushed) {
1096 if (nr_pages == 0)
1097 nullb->cache_flush_pos = 0;
1098 if (one_round == 0) {
1099 /* give other threads a chance */
1100 spin_unlock_irq(&nullb->lock);
1101 spin_lock_irq(&nullb->lock);
1102 }
1103 goto again;
1104 }
1105 return 0;
1106 }
1107
1108 static int copy_to_nullb(struct nullb *nullb, struct page *source,
1109 unsigned int off, sector_t sector, size_t n, bool is_fua)
1110 {
1111 size_t temp, count = 0;
1112 unsigned int offset;
1113 struct nullb_page *t_page;
1114
1115 while (count < n) {
1116 temp = min_t(size_t, nullb->dev->blocksize, n - count);
1117
1118 if (null_cache_active(nullb) && !is_fua)
1119 null_make_cache_space(nullb, PAGE_SIZE);
1120
1121 offset = (sector & SECTOR_MASK) << SECTOR_SHIFT;
1122 t_page = null_insert_page(nullb, sector,
1123 !null_cache_active(nullb) || is_fua);
1124 if (!t_page)
1125 return -ENOSPC;
1126
1127 memcpy_page(t_page->page, offset, source, off + count, temp);
1128
1129 __set_bit(sector & SECTOR_MASK, t_page->bitmap);
1130
1131 if (is_fua)
1132 null_free_sector(nullb, sector, true);
1133
1134 count += temp;
1135 sector += temp >> SECTOR_SHIFT;
1136 }
1137 return 0;
1138 }
1139
1140 static int copy_from_nullb(struct nullb *nullb, struct page *dest,
1141 unsigned int off, sector_t sector, size_t n)
1142 {
1143 size_t temp, count = 0;
1144 unsigned int offset;
1145 struct nullb_page *t_page;
1146
1147 while (count < n) {
1148 temp = min_t(size_t, nullb->dev->blocksize, n - count);
1149
1150 offset = (sector & SECTOR_MASK) << SECTOR_SHIFT;
1151 t_page = null_lookup_page(nullb, sector, false,
1152 !null_cache_active(nullb));
1153
1154 if (t_page)
1155 memcpy_page(dest, off + count, t_page->page, offset,
1156 temp);
1157 else
1158 zero_user(dest, off + count, temp);
1159
1160 count += temp;
1161 sector += temp >> SECTOR_SHIFT;
1162 }
1163 return 0;
1164 }
1165
1166 static void nullb_fill_pattern(struct nullb *nullb, struct page *page,
1167 unsigned int len, unsigned int off)
1168 {
1169 memset_page(page, off, 0xff, len);
1170 }
1171
1172 blk_status_t null_handle_discard(struct nullb_device *dev,
1173 sector_t sector, sector_t nr_sectors)
1174 {
1175 struct nullb *nullb = dev->nullb;
1176 size_t n = nr_sectors << SECTOR_SHIFT;
1177 size_t temp;
1178
1179 spin_lock_irq(&nullb->lock);
1180 while (n > 0) {
1181 temp = min_t(size_t, n, dev->blocksize);
1182 null_free_sector(nullb, sector, false);
1183 if (null_cache_active(nullb))
1184 null_free_sector(nullb, sector, true);
1185 sector += temp >> SECTOR_SHIFT;
1186 n -= temp;
1187 }
1188 spin_unlock_irq(&nullb->lock);
1189
1190 return BLK_STS_OK;
1191 }
1192
1193 static blk_status_t null_handle_flush(struct nullb *nullb)
1194 {
1195 int err;
1196
1197 if (!null_cache_active(nullb))
1198 return 0;
1199
1200 spin_lock_irq(&nullb->lock);
1201 while (true) {
1202 err = null_make_cache_space(nullb,
1203 nullb->dev->cache_size * 1024 * 1024);
1204 if (err || nullb->dev->curr_cache == 0)
1205 break;
1206 }
1207
1208 WARN_ON(!radix_tree_empty(&nullb->dev->cache));
1209 spin_unlock_irq(&nullb->lock);
1210 return errno_to_blk_status(err);
1211 }
1212
1213 static int null_transfer(struct nullb *nullb, struct page *page,
1214 unsigned int len, unsigned int off, bool is_write, sector_t sector,
1215 bool is_fua)
1216 {
1217 struct nullb_device *dev = nullb->dev;
1218 unsigned int valid_len = len;
1219 int err = 0;
1220
1221 if (!is_write) {
1222 if (dev->zoned)
1223 valid_len = null_zone_valid_read_len(nullb,
1224 sector, len);
1225
1226 if (valid_len) {
1227 err = copy_from_nullb(nullb, page, off,
1228 sector, valid_len);
1229 off += valid_len;
1230 len -= valid_len;
1231 }
1232
1233 if (len)
1234 nullb_fill_pattern(nullb, page, len, off);
1235 flush_dcache_page(page);
1236 } else {
1237 flush_dcache_page(page);
1238 err = copy_to_nullb(nullb, page, off, sector, len, is_fua);
1239 }
1240
1241 return err;
1242 }
1243
1244 static blk_status_t null_handle_rq(struct nullb_cmd *cmd)
1245 {
1246 struct request *rq = blk_mq_rq_from_pdu(cmd);
1247 struct nullb *nullb = cmd->nq->dev->nullb;
1248 int err = 0;
1249 unsigned int len;
1250 sector_t sector = blk_rq_pos(rq);
1251 struct req_iterator iter;
1252 struct bio_vec bvec;
1253
1254 spin_lock_irq(&nullb->lock);
1255 rq_for_each_segment(bvec, rq, iter) {
1256 len = bvec.bv_len;
1257 err = null_transfer(nullb, bvec.bv_page, len, bvec.bv_offset,
1258 op_is_write(req_op(rq)), sector,
1259 rq->cmd_flags & REQ_FUA);
1260 if (err)
1261 break;
1262 sector += len >> SECTOR_SHIFT;
1263 }
1264 spin_unlock_irq(&nullb->lock);
1265
1266 return errno_to_blk_status(err);
1267 }
1268
1269 static inline blk_status_t null_handle_throttled(struct nullb_cmd *cmd)
1270 {
1271 struct nullb_device *dev = cmd->nq->dev;
1272 struct nullb *nullb = dev->nullb;
1273 blk_status_t sts = BLK_STS_OK;
1274 struct request *rq = blk_mq_rq_from_pdu(cmd);
1275
1276 if (!hrtimer_active(&nullb->bw_timer))
1277 hrtimer_restart(&nullb->bw_timer);
1278
1279 if (atomic_long_sub_return(blk_rq_bytes(rq), &nullb->cur_bytes) < 0) {
1280 blk_mq_stop_hw_queues(nullb->q);
1281 /* race with timer */
1282 if (atomic_long_read(&nullb->cur_bytes) > 0)
1283 blk_mq_start_stopped_hw_queues(nullb->q, true);
1284 /* requeue request */
1285 sts = BLK_STS_DEV_RESOURCE;
1286 }
1287 return sts;
1288 }
1289
1290 static inline blk_status_t null_handle_badblocks(struct nullb_cmd *cmd,
1291 sector_t sector,
1292 sector_t nr_sectors)
1293 {
1294 struct badblocks *bb = &cmd->nq->dev->badblocks;
1295 sector_t first_bad;
1296 int bad_sectors;
1297
1298 if (badblocks_check(bb, sector, nr_sectors, &first_bad, &bad_sectors))
1299 return BLK_STS_IOERR;
1300
1301 return BLK_STS_OK;
1302 }
1303
1304 static inline blk_status_t null_handle_memory_backed(struct nullb_cmd *cmd,
1305 enum req_op op,
1306 sector_t sector,
1307 sector_t nr_sectors)
1308 {
1309 struct nullb_device *dev = cmd->nq->dev;
1310
1311 if (op == REQ_OP_DISCARD)
1312 return null_handle_discard(dev, sector, nr_sectors);
1313
1314 return null_handle_rq(cmd);
1315 }
1316
1317 static void nullb_zero_read_cmd_buffer(struct nullb_cmd *cmd)
1318 {
1319 struct request *rq = blk_mq_rq_from_pdu(cmd);
1320 struct nullb_device *dev = cmd->nq->dev;
1321 struct bio *bio;
1322
1323 if (!dev->memory_backed && req_op(rq) == REQ_OP_READ) {
1324 __rq_for_each_bio(bio, rq)
1325 zero_fill_bio(bio);
1326 }
1327 }
1328
1329 static inline void nullb_complete_cmd(struct nullb_cmd *cmd)
1330 {
1331 struct request *rq = blk_mq_rq_from_pdu(cmd);
1332
1333 /*
1334 * Since root privileges are required to configure the null_blk
1335 * driver, it is fine that this driver does not initialize the
1336 * data buffers of read commands. Zero-initialize these buffers
1337 * anyway if KMSAN is enabled to prevent that KMSAN complains
1338 * about null_blk not initializing read data buffers.
1339 */
1340 if (IS_ENABLED(CONFIG_KMSAN))
1341 nullb_zero_read_cmd_buffer(cmd);
1342
1343 /* Complete IO by inline, softirq or timer */
1344 switch (cmd->nq->dev->irqmode) {
1345 case NULL_IRQ_SOFTIRQ:
1346 blk_mq_complete_request(rq);
1347 break;
1348 case NULL_IRQ_NONE:
1349 blk_mq_end_request(rq, cmd->error);
1350 break;
1351 case NULL_IRQ_TIMER:
1352 null_cmd_end_timer(cmd);
1353 break;
1354 }
1355 }
1356
1357 blk_status_t null_process_cmd(struct nullb_cmd *cmd, enum req_op op,
1358 sector_t sector, unsigned int nr_sectors)
1359 {
1360 struct nullb_device *dev = cmd->nq->dev;
1361 blk_status_t ret;
1362
1363 if (dev->badblocks.shift != -1) {
1364 ret = null_handle_badblocks(cmd, sector, nr_sectors);
1365 if (ret != BLK_STS_OK)
1366 return ret;
1367 }
1368
1369 if (dev->memory_backed)
1370 return null_handle_memory_backed(cmd, op, sector, nr_sectors);
1371
1372 return BLK_STS_OK;
1373 }
1374
1375 static void null_handle_cmd(struct nullb_cmd *cmd, sector_t sector,
1376 sector_t nr_sectors, enum req_op op)
1377 {
1378 struct nullb_device *dev = cmd->nq->dev;
1379 struct nullb *nullb = dev->nullb;
1380 blk_status_t sts;
1381
1382 if (op == REQ_OP_FLUSH) {
1383 cmd->error = null_handle_flush(nullb);
1384 goto out;
1385 }
1386
1387 if (dev->zoned)
1388 sts = null_process_zoned_cmd(cmd, op, sector, nr_sectors);
1389 else
1390 sts = null_process_cmd(cmd, op, sector, nr_sectors);
1391
1392 /* Do not overwrite errors (e.g. timeout errors) */
1393 if (cmd->error == BLK_STS_OK)
1394 cmd->error = sts;
1395
1396 out:
1397 nullb_complete_cmd(cmd);
1398 }
1399
1400 static enum hrtimer_restart nullb_bwtimer_fn(struct hrtimer *timer)
1401 {
1402 struct nullb *nullb = container_of(timer, struct nullb, bw_timer);
1403 ktime_t timer_interval = ktime_set(0, TIMER_INTERVAL);
1404 unsigned int mbps = nullb->dev->mbps;
1405
1406 if (atomic_long_read(&nullb->cur_bytes) == mb_per_tick(mbps))
1407 return HRTIMER_NORESTART;
1408
1409 atomic_long_set(&nullb->cur_bytes, mb_per_tick(mbps));
1410 blk_mq_start_stopped_hw_queues(nullb->q, true);
1411
1412 hrtimer_forward_now(&nullb->bw_timer, timer_interval);
1413
1414 return HRTIMER_RESTART;
1415 }
1416
1417 static void nullb_setup_bwtimer(struct nullb *nullb)
1418 {
1419 ktime_t timer_interval = ktime_set(0, TIMER_INTERVAL);
1420
1421 hrtimer_init(&nullb->bw_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
1422 nullb->bw_timer.function = nullb_bwtimer_fn;
1423 atomic_long_set(&nullb->cur_bytes, mb_per_tick(nullb->dev->mbps));
1424 hrtimer_start(&nullb->bw_timer, timer_interval, HRTIMER_MODE_REL);
1425 }
1426
1427 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
1428
1429 static bool should_timeout_request(struct request *rq)
1430 {
1431 struct nullb_cmd *cmd = blk_mq_rq_to_pdu(rq);
1432 struct nullb_device *dev = cmd->nq->dev;
1433
1434 return should_fail(&dev->timeout_config.attr, 1);
1435 }
1436
1437 static bool should_requeue_request(struct request *rq)
1438 {
1439 struct nullb_cmd *cmd = blk_mq_rq_to_pdu(rq);
1440 struct nullb_device *dev = cmd->nq->dev;
1441
1442 return should_fail(&dev->requeue_config.attr, 1);
1443 }
1444
1445 static bool should_init_hctx_fail(struct nullb_device *dev)
1446 {
1447 return should_fail(&dev->init_hctx_fault_config.attr, 1);
1448 }
1449
1450 #else
1451
1452 static bool should_timeout_request(struct request *rq)
1453 {
1454 return false;
1455 }
1456
1457 static bool should_requeue_request(struct request *rq)
1458 {
1459 return false;
1460 }
1461
1462 static bool should_init_hctx_fail(struct nullb_device *dev)
1463 {
1464 return false;
1465 }
1466
1467 #endif
1468
1469 static void null_map_queues(struct blk_mq_tag_set *set)
1470 {
1471 struct nullb *nullb = set->driver_data;
1472 int i, qoff;
1473 unsigned int submit_queues = g_submit_queues;
1474 unsigned int poll_queues = g_poll_queues;
1475
1476 if (nullb) {
1477 struct nullb_device *dev = nullb->dev;
1478
1479 /*
1480 * Refer nr_hw_queues of the tag set to check if the expected
1481 * number of hardware queues are prepared. If block layer failed
1482 * to prepare them, use previous numbers of submit queues and
1483 * poll queues to map queues.
1484 */
1485 if (set->nr_hw_queues ==
1486 dev->submit_queues + dev->poll_queues) {
1487 submit_queues = dev->submit_queues;
1488 poll_queues = dev->poll_queues;
1489 } else if (set->nr_hw_queues ==
1490 dev->prev_submit_queues + dev->prev_poll_queues) {
1491 submit_queues = dev->prev_submit_queues;
1492 poll_queues = dev->prev_poll_queues;
1493 } else {
1494 pr_warn("tag set has unexpected nr_hw_queues: %d\n",
1495 set->nr_hw_queues);
1496 WARN_ON_ONCE(true);
1497 submit_queues = 1;
1498 poll_queues = 0;
1499 }
1500 }
1501
1502 for (i = 0, qoff = 0; i < set->nr_maps; i++) {
1503 struct blk_mq_queue_map *map = &set->map[i];
1504
1505 switch (i) {
1506 case HCTX_TYPE_DEFAULT:
1507 map->nr_queues = submit_queues;
1508 break;
1509 case HCTX_TYPE_READ:
1510 map->nr_queues = 0;
1511 continue;
1512 case HCTX_TYPE_POLL:
1513 map->nr_queues = poll_queues;
1514 break;
1515 }
1516 map->queue_offset = qoff;
1517 qoff += map->nr_queues;
1518 blk_mq_map_queues(map);
1519 }
1520 }
1521
1522 static int null_poll(struct blk_mq_hw_ctx *hctx, struct io_comp_batch *iob)
1523 {
1524 struct nullb_queue *nq = hctx->driver_data;
1525 LIST_HEAD(list);
1526 int nr = 0;
1527 struct request *rq;
1528
1529 spin_lock(&nq->poll_lock);
1530 list_splice_init(&nq->poll_list, &list);
1531 list_for_each_entry(rq, &list, queuelist)
1532 blk_mq_set_request_complete(rq);
1533 spin_unlock(&nq->poll_lock);
1534
1535 while (!list_empty(&list)) {
1536 struct nullb_cmd *cmd;
1537 struct request *req;
1538
1539 req = list_first_entry(&list, struct request, queuelist);
1540 list_del_init(&req->queuelist);
1541 cmd = blk_mq_rq_to_pdu(req);
1542 cmd->error = null_process_cmd(cmd, req_op(req), blk_rq_pos(req),
1543 blk_rq_sectors(req));
1544 if (!blk_mq_add_to_batch(req, iob, (__force int) cmd->error,
1545 blk_mq_end_request_batch))
1546 blk_mq_end_request(req, cmd->error);
1547 nr++;
1548 }
1549
1550 return nr;
1551 }
1552
1553 static enum blk_eh_timer_return null_timeout_rq(struct request *rq)
1554 {
1555 struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
1556 struct nullb_cmd *cmd = blk_mq_rq_to_pdu(rq);
1557
1558 if (hctx->type == HCTX_TYPE_POLL) {
1559 struct nullb_queue *nq = hctx->driver_data;
1560
1561 spin_lock(&nq->poll_lock);
1562 /* The request may have completed meanwhile. */
1563 if (blk_mq_request_completed(rq)) {
1564 spin_unlock(&nq->poll_lock);
1565 return BLK_EH_DONE;
1566 }
1567 list_del_init(&rq->queuelist);
1568 spin_unlock(&nq->poll_lock);
1569 }
1570
1571 pr_info("rq %p timed out\n", rq);
1572
1573 /*
1574 * If the device is marked as blocking (i.e. memory backed or zoned
1575 * device), the submission path may be blocked waiting for resources
1576 * and cause real timeouts. For these real timeouts, the submission
1577 * path will complete the request using blk_mq_complete_request().
1578 * Only fake timeouts need to execute blk_mq_complete_request() here.
1579 */
1580 cmd->error = BLK_STS_TIMEOUT;
1581 if (cmd->fake_timeout || hctx->type == HCTX_TYPE_POLL)
1582 blk_mq_complete_request(rq);
1583 return BLK_EH_DONE;
1584 }
1585
1586 static blk_status_t null_queue_rq(struct blk_mq_hw_ctx *hctx,
1587 const struct blk_mq_queue_data *bd)
1588 {
1589 struct request *rq = bd->rq;
1590 struct nullb_cmd *cmd = blk_mq_rq_to_pdu(rq);
1591 struct nullb_queue *nq = hctx->driver_data;
1592 sector_t nr_sectors = blk_rq_sectors(rq);
1593 sector_t sector = blk_rq_pos(rq);
1594 const bool is_poll = hctx->type == HCTX_TYPE_POLL;
1595
1596 might_sleep_if(hctx->flags & BLK_MQ_F_BLOCKING);
1597
1598 if (!is_poll && nq->dev->irqmode == NULL_IRQ_TIMER) {
1599 hrtimer_init(&cmd->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
1600 cmd->timer.function = null_cmd_timer_expired;
1601 }
1602 cmd->error = BLK_STS_OK;
1603 cmd->nq = nq;
1604 cmd->fake_timeout = should_timeout_request(rq) ||
1605 blk_should_fake_timeout(rq->q);
1606
1607 if (should_requeue_request(rq)) {
1608 /*
1609 * Alternate between hitting the core BUSY path, and the
1610 * driver driven requeue path
1611 */
1612 nq->requeue_selection++;
1613 if (nq->requeue_selection & 1)
1614 return BLK_STS_RESOURCE;
1615 blk_mq_requeue_request(rq, true);
1616 return BLK_STS_OK;
1617 }
1618
1619 if (test_bit(NULLB_DEV_FL_THROTTLED, &nq->dev->flags)) {
1620 blk_status_t sts = null_handle_throttled(cmd);
1621
1622 if (sts != BLK_STS_OK)
1623 return sts;
1624 }
1625
1626 blk_mq_start_request(rq);
1627
1628 if (is_poll) {
1629 spin_lock(&nq->poll_lock);
1630 list_add_tail(&rq->queuelist, &nq->poll_list);
1631 spin_unlock(&nq->poll_lock);
1632 return BLK_STS_OK;
1633 }
1634 if (cmd->fake_timeout)
1635 return BLK_STS_OK;
1636
1637 null_handle_cmd(cmd, sector, nr_sectors, req_op(rq));
1638 return BLK_STS_OK;
1639 }
1640
1641 static void null_queue_rqs(struct rq_list *rqlist)
1642 {
1643 struct rq_list requeue_list = {};
1644 struct blk_mq_queue_data bd = { };
1645 blk_status_t ret;
1646
1647 do {
1648 struct request *rq = rq_list_pop(rqlist);
1649
1650 bd.rq = rq;
1651 ret = null_queue_rq(rq->mq_hctx, &bd);
1652 if (ret != BLK_STS_OK)
1653 rq_list_add_tail(&requeue_list, rq);
1654 } while (!rq_list_empty(rqlist));
1655
1656 *rqlist = requeue_list;
1657 }
1658
1659 static void null_init_queue(struct nullb *nullb, struct nullb_queue *nq)
1660 {
1661 nq->dev = nullb->dev;
1662 INIT_LIST_HEAD(&nq->poll_list);
1663 spin_lock_init(&nq->poll_lock);
1664 }
1665
1666 static int null_init_hctx(struct blk_mq_hw_ctx *hctx, void *driver_data,
1667 unsigned int hctx_idx)
1668 {
1669 struct nullb *nullb = hctx->queue->queuedata;
1670 struct nullb_queue *nq;
1671
1672 if (should_init_hctx_fail(nullb->dev))
1673 return -EFAULT;
1674
1675 nq = &nullb->queues[hctx_idx];
1676 hctx->driver_data = nq;
1677 null_init_queue(nullb, nq);
1678
1679 return 0;
1680 }
1681
1682 static const struct blk_mq_ops null_mq_ops = {
1683 .queue_rq = null_queue_rq,
1684 .queue_rqs = null_queue_rqs,
1685 .complete = null_complete_rq,
1686 .timeout = null_timeout_rq,
1687 .poll = null_poll,
1688 .map_queues = null_map_queues,
1689 .init_hctx = null_init_hctx,
1690 };
1691
1692 static void null_del_dev(struct nullb *nullb)
1693 {
1694 struct nullb_device *dev;
1695
1696 if (!nullb)
1697 return;
1698
1699 dev = nullb->dev;
1700
1701 ida_free(&nullb_indexes, nullb->index);
1702
1703 list_del_init(&nullb->list);
1704
1705 del_gendisk(nullb->disk);
1706
1707 if (test_bit(NULLB_DEV_FL_THROTTLED, &nullb->dev->flags)) {
1708 hrtimer_cancel(&nullb->bw_timer);
1709 atomic_long_set(&nullb->cur_bytes, LONG_MAX);
1710 blk_mq_start_stopped_hw_queues(nullb->q, true);
1711 }
1712
1713 put_disk(nullb->disk);
1714 if (nullb->tag_set == &nullb->__tag_set)
1715 blk_mq_free_tag_set(nullb->tag_set);
1716 kfree(nullb->queues);
1717 if (null_cache_active(nullb))
1718 null_free_device_storage(nullb->dev, true);
1719 kfree(nullb);
1720 dev->nullb = NULL;
1721 }
1722
1723 static void null_config_discard(struct nullb *nullb, struct queue_limits *lim)
1724 {
1725 if (nullb->dev->discard == false)
1726 return;
1727
1728 if (!nullb->dev->memory_backed) {
1729 nullb->dev->discard = false;
1730 pr_info("discard option is ignored without memory backing\n");
1731 return;
1732 }
1733
1734 if (nullb->dev->zoned) {
1735 nullb->dev->discard = false;
1736 pr_info("discard option is ignored in zoned mode\n");
1737 return;
1738 }
1739
1740 lim->max_hw_discard_sectors = UINT_MAX >> 9;
1741 }
1742
1743 static const struct block_device_operations null_ops = {
1744 .owner = THIS_MODULE,
1745 .report_zones = null_report_zones,
1746 };
1747
1748 static int setup_queues(struct nullb *nullb)
1749 {
1750 int nqueues = nr_cpu_ids;
1751
1752 if (g_poll_queues)
1753 nqueues += g_poll_queues;
1754
1755 nullb->queues = kcalloc(nqueues, sizeof(struct nullb_queue),
1756 GFP_KERNEL);
1757 if (!nullb->queues)
1758 return -ENOMEM;
1759
1760 return 0;
1761 }
1762
1763 static int null_init_tag_set(struct blk_mq_tag_set *set, int poll_queues)
1764 {
1765 set->ops = &null_mq_ops;
1766 set->cmd_size = sizeof(struct nullb_cmd);
1767 set->timeout = 5 * HZ;
1768 set->nr_maps = 1;
1769 if (poll_queues) {
1770 set->nr_hw_queues += poll_queues;
1771 set->nr_maps += 2;
1772 }
1773 return blk_mq_alloc_tag_set(set);
1774 }
1775
1776 static int null_init_global_tag_set(void)
1777 {
1778 int error;
1779
1780 if (tag_set.ops)
1781 return 0;
1782
1783 tag_set.nr_hw_queues = g_submit_queues;
1784 tag_set.queue_depth = g_hw_queue_depth;
1785 tag_set.numa_node = g_home_node;
1786 tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
1787 if (g_no_sched)
1788 tag_set.flags |= BLK_MQ_F_NO_SCHED;
1789 if (g_shared_tag_bitmap)
1790 tag_set.flags |= BLK_MQ_F_TAG_HCTX_SHARED;
1791 if (g_blocking)
1792 tag_set.flags |= BLK_MQ_F_BLOCKING;
1793
1794 error = null_init_tag_set(&tag_set, g_poll_queues);
1795 if (error)
1796 tag_set.ops = NULL;
1797 return error;
1798 }
1799
1800 static int null_setup_tagset(struct nullb *nullb)
1801 {
1802 if (nullb->dev->shared_tags) {
1803 nullb->tag_set = &tag_set;
1804 return null_init_global_tag_set();
1805 }
1806
1807 nullb->tag_set = &nullb->__tag_set;
1808 nullb->tag_set->driver_data = nullb;
1809 nullb->tag_set->nr_hw_queues = nullb->dev->submit_queues;
1810 nullb->tag_set->queue_depth = nullb->dev->hw_queue_depth;
1811 nullb->tag_set->numa_node = nullb->dev->home_node;
1812 nullb->tag_set->flags = BLK_MQ_F_SHOULD_MERGE;
1813 if (nullb->dev->no_sched)
1814 nullb->tag_set->flags |= BLK_MQ_F_NO_SCHED;
1815 if (nullb->dev->shared_tag_bitmap)
1816 nullb->tag_set->flags |= BLK_MQ_F_TAG_HCTX_SHARED;
1817 if (nullb->dev->blocking)
1818 nullb->tag_set->flags |= BLK_MQ_F_BLOCKING;
1819 return null_init_tag_set(nullb->tag_set, nullb->dev->poll_queues);
1820 }
1821
1822 static int null_validate_conf(struct nullb_device *dev)
1823 {
1824 if (dev->queue_mode == NULL_Q_RQ) {
1825 pr_err("legacy IO path is no longer available\n");
1826 return -EINVAL;
1827 }
1828 if (dev->queue_mode == NULL_Q_BIO) {
1829 pr_err("BIO-based IO path is no longer available, using blk-mq instead.\n");
1830 dev->queue_mode = NULL_Q_MQ;
1831 }
1832
1833 if (dev->use_per_node_hctx) {
1834 if (dev->submit_queues != nr_online_nodes)
1835 dev->submit_queues = nr_online_nodes;
1836 } else if (dev->submit_queues > nr_cpu_ids)
1837 dev->submit_queues = nr_cpu_ids;
1838 else if (dev->submit_queues == 0)
1839 dev->submit_queues = 1;
1840 dev->prev_submit_queues = dev->submit_queues;
1841
1842 if (dev->poll_queues > g_poll_queues)
1843 dev->poll_queues = g_poll_queues;
1844 dev->prev_poll_queues = dev->poll_queues;
1845 dev->irqmode = min_t(unsigned int, dev->irqmode, NULL_IRQ_TIMER);
1846
1847 /* Do memory allocation, so set blocking */
1848 if (dev->memory_backed)
1849 dev->blocking = true;
1850 else /* cache is meaningless */
1851 dev->cache_size = 0;
1852 dev->cache_size = min_t(unsigned long, ULONG_MAX / 1024 / 1024,
1853 dev->cache_size);
1854 dev->mbps = min_t(unsigned int, 1024 * 40, dev->mbps);
1855
1856 if (dev->zoned &&
1857 (!dev->zone_size || !is_power_of_2(dev->zone_size))) {
1858 pr_err("zone_size must be power-of-two\n");
1859 return -EINVAL;
1860 }
1861
1862 return 0;
1863 }
1864
1865 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
1866 static bool __null_setup_fault(struct fault_attr *attr, char *str)
1867 {
1868 if (!str[0])
1869 return true;
1870
1871 if (!setup_fault_attr(attr, str))
1872 return false;
1873
1874 attr->verbose = 0;
1875 return true;
1876 }
1877 #endif
1878
1879 static bool null_setup_fault(void)
1880 {
1881 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
1882 if (!__null_setup_fault(&null_timeout_attr, g_timeout_str))
1883 return false;
1884 if (!__null_setup_fault(&null_requeue_attr, g_requeue_str))
1885 return false;
1886 if (!__null_setup_fault(&null_init_hctx_attr, g_init_hctx_str))
1887 return false;
1888 #endif
1889 return true;
1890 }
1891
1892 static int null_add_dev(struct nullb_device *dev)
1893 {
1894 struct queue_limits lim = {
1895 .logical_block_size = dev->blocksize,
1896 .physical_block_size = dev->blocksize,
1897 .max_hw_sectors = dev->max_sectors,
1898 };
1899
1900 struct nullb *nullb;
1901 int rv;
1902
1903 rv = null_validate_conf(dev);
1904 if (rv)
1905 return rv;
1906
1907 nullb = kzalloc_node(sizeof(*nullb), GFP_KERNEL, dev->home_node);
1908 if (!nullb) {
1909 rv = -ENOMEM;
1910 goto out;
1911 }
1912 nullb->dev = dev;
1913 dev->nullb = nullb;
1914
1915 spin_lock_init(&nullb->lock);
1916
1917 rv = setup_queues(nullb);
1918 if (rv)
1919 goto out_free_nullb;
1920
1921 rv = null_setup_tagset(nullb);
1922 if (rv)
1923 goto out_cleanup_queues;
1924
1925 if (dev->virt_boundary)
1926 lim.virt_boundary_mask = PAGE_SIZE - 1;
1927 null_config_discard(nullb, &lim);
1928 if (dev->zoned) {
1929 rv = null_init_zoned_dev(dev, &lim);
1930 if (rv)
1931 goto out_cleanup_tags;
1932 }
1933
1934 if (dev->cache_size > 0) {
1935 set_bit(NULLB_DEV_FL_CACHE, &nullb->dev->flags);
1936 lim.features |= BLK_FEAT_WRITE_CACHE;
1937 if (dev->fua)
1938 lim.features |= BLK_FEAT_FUA;
1939 }
1940
1941 nullb->disk = blk_mq_alloc_disk(nullb->tag_set, &lim, nullb);
1942 if (IS_ERR(nullb->disk)) {
1943 rv = PTR_ERR(nullb->disk);
1944 goto out_cleanup_zone;
1945 }
1946 nullb->q = nullb->disk->queue;
1947
1948 if (dev->mbps) {
1949 set_bit(NULLB_DEV_FL_THROTTLED, &dev->flags);
1950 nullb_setup_bwtimer(nullb);
1951 }
1952
1953 nullb->q->queuedata = nullb;
1954
1955 rv = ida_alloc(&nullb_indexes, GFP_KERNEL);
1956 if (rv < 0)
1957 goto out_cleanup_disk;
1958
1959 nullb->index = rv;
1960 dev->index = rv;
1961
1962 if (config_item_name(&dev->group.cg_item)) {
1963 /* Use configfs dir name as the device name */
1964 snprintf(nullb->disk_name, sizeof(nullb->disk_name),
1965 "%s", config_item_name(&dev->group.cg_item));
1966 } else {
1967 sprintf(nullb->disk_name, "nullb%d", nullb->index);
1968 }
1969
1970 set_capacity(nullb->disk,
1971 ((sector_t)nullb->dev->size * SZ_1M) >> SECTOR_SHIFT);
1972 nullb->disk->major = null_major;
1973 nullb->disk->first_minor = nullb->index;
1974 nullb->disk->minors = 1;
1975 nullb->disk->fops = &null_ops;
1976 nullb->disk->private_data = nullb;
1977 strscpy_pad(nullb->disk->disk_name, nullb->disk_name, DISK_NAME_LEN);
1978
1979 if (nullb->dev->zoned) {
1980 rv = null_register_zoned_dev(nullb);
1981 if (rv)
1982 goto out_ida_free;
1983 }
1984
1985 rv = add_disk(nullb->disk);
1986 if (rv)
1987 goto out_ida_free;
1988
1989 list_add_tail(&nullb->list, &nullb_list);
1990
1991 pr_info("disk %s created\n", nullb->disk_name);
1992
1993 return 0;
1994
1995 out_ida_free:
1996 ida_free(&nullb_indexes, nullb->index);
1997 out_cleanup_disk:
1998 put_disk(nullb->disk);
1999 out_cleanup_zone:
2000 null_free_zoned_dev(dev);
2001 out_cleanup_tags:
2002 if (nullb->tag_set == &nullb->__tag_set)
2003 blk_mq_free_tag_set(nullb->tag_set);
2004 out_cleanup_queues:
2005 kfree(nullb->queues);
2006 out_free_nullb:
2007 kfree(nullb);
2008 dev->nullb = NULL;
2009 out:
2010 return rv;
2011 }
2012
2013 static struct nullb *null_find_dev_by_name(const char *name)
2014 {
2015 struct nullb *nullb = NULL, *nb;
2016
2017 mutex_lock(&lock);
2018 list_for_each_entry(nb, &nullb_list, list) {
2019 if (strcmp(nb->disk_name, name) == 0) {
2020 nullb = nb;
2021 break;
2022 }
2023 }
2024 mutex_unlock(&lock);
2025
2026 return nullb;
2027 }
2028
2029 static int null_create_dev(void)
2030 {
2031 struct nullb_device *dev;
2032 int ret;
2033
2034 dev = null_alloc_dev();
2035 if (!dev)
2036 return -ENOMEM;
2037
2038 mutex_lock(&lock);
2039 ret = null_add_dev(dev);
2040 mutex_unlock(&lock);
2041 if (ret) {
2042 null_free_dev(dev);
2043 return ret;
2044 }
2045
2046 return 0;
2047 }
2048
2049 static void null_destroy_dev(struct nullb *nullb)
2050 {
2051 struct nullb_device *dev = nullb->dev;
2052
2053 null_del_dev(nullb);
2054 null_free_device_storage(dev, false);
2055 null_free_dev(dev);
2056 }
2057
2058 static int __init null_init(void)
2059 {
2060 int ret = 0;
2061 unsigned int i;
2062 struct nullb *nullb;
2063
2064 if (g_bs > PAGE_SIZE) {
2065 pr_warn("invalid block size\n");
2066 pr_warn("defaults block size to %lu\n", PAGE_SIZE);
2067 g_bs = PAGE_SIZE;
2068 }
2069
2070 if (g_home_node != NUMA_NO_NODE && g_home_node >= nr_online_nodes) {
2071 pr_err("invalid home_node value\n");
2072 g_home_node = NUMA_NO_NODE;
2073 }
2074
2075 if (!null_setup_fault())
2076 return -EINVAL;
2077
2078 if (g_queue_mode == NULL_Q_RQ) {
2079 pr_err("legacy IO path is no longer available\n");
2080 return -EINVAL;
2081 }
2082
2083 if (g_use_per_node_hctx) {
2084 if (g_submit_queues != nr_online_nodes) {
2085 pr_warn("submit_queues param is set to %u.\n",
2086 nr_online_nodes);
2087 g_submit_queues = nr_online_nodes;
2088 }
2089 } else if (g_submit_queues > nr_cpu_ids) {
2090 g_submit_queues = nr_cpu_ids;
2091 } else if (g_submit_queues <= 0) {
2092 g_submit_queues = 1;
2093 }
2094
2095 config_group_init(&nullb_subsys.su_group);
2096 mutex_init(&nullb_subsys.su_mutex);
2097
2098 ret = configfs_register_subsystem(&nullb_subsys);
2099 if (ret)
2100 return ret;
2101
2102 mutex_init(&lock);
2103
2104 null_major = register_blkdev(0, "nullb");
2105 if (null_major < 0) {
2106 ret = null_major;
2107 goto err_conf;
2108 }
2109
2110 for (i = 0; i < nr_devices; i++) {
2111 ret = null_create_dev();
2112 if (ret)
2113 goto err_dev;
2114 }
2115
2116 pr_info("module loaded\n");
2117 return 0;
2118
2119 err_dev:
2120 while (!list_empty(&nullb_list)) {
2121 nullb = list_entry(nullb_list.next, struct nullb, list);
2122 null_destroy_dev(nullb);
2123 }
2124 unregister_blkdev(null_major, "nullb");
2125 err_conf:
2126 configfs_unregister_subsystem(&nullb_subsys);
2127 return ret;
2128 }
2129
2130 static void __exit null_exit(void)
2131 {
2132 struct nullb *nullb;
2133
2134 configfs_unregister_subsystem(&nullb_subsys);
2135
2136 unregister_blkdev(null_major, "nullb");
2137
2138 mutex_lock(&lock);
2139 while (!list_empty(&nullb_list)) {
2140 nullb = list_entry(nullb_list.next, struct nullb, list);
2141 null_destroy_dev(nullb);
2142 }
2143 mutex_unlock(&lock);
2144
2145 if (tag_set.ops)
2146 blk_mq_free_tag_set(&tag_set);
2147
2148 mutex_destroy(&lock);
2149 }
2150
2151 module_init(null_init);
2152 module_exit(null_exit);
2153
2154 MODULE_AUTHOR("Jens Axboe <axboe@kernel.dk>");
2155 MODULE_DESCRIPTION("multi queue aware block test driver");
2156 MODULE_LICENSE("GPL");
Linux Kernel