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 FREE_BATCH 16
15
16 #define TICKS_PER_SEC 50ULL
17 #define TIMER_INTERVAL (NSEC_PER_SEC / TICKS_PER_SEC)
18
19 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
20 static DECLARE_FAULT_ATTR(null_timeout_attr);
21 static DECLARE_FAULT_ATTR(null_requeue_attr);
22 static DECLARE_FAULT_ATTR(null_init_hctx_attr);
23 #endif
24
mb_per_tick(int mbps)25 static inline u64 mb_per_tick(int mbps)
26 {
27 return (1 << 20) / TICKS_PER_SEC * ((u64) mbps);
28 }
29
30 /*
31 * Status flags for nullb_device.
32 *
33 * CONFIGURED: Device has been configured and turned on. Cannot reconfigure.
34 * UP: Device is currently on and visible in userspace.
35 * THROTTLED: Device is being throttled.
36 * CACHE: Device is using a write-back cache.
37 */
38 enum nullb_device_flags {
39 NULLB_DEV_FL_CONFIGURED = 0,
40 NULLB_DEV_FL_UP = 1,
41 NULLB_DEV_FL_THROTTLED = 2,
42 NULLB_DEV_FL_CACHE = 3,
43 };
44
45 #define MAP_SZ ((PAGE_SIZE >> SECTOR_SHIFT) + 2)
46 /*
47 * nullb_page is a page in memory for nullb devices.
48 *
49 * @page: The page holding the data.
50 * @bitmap: The bitmap represents which sector in the page has data.
51 * Each bit represents one block size. For example, sector 8
52 * will use the 7th bit
53 * The highest 2 bits of bitmap are for special purpose. LOCK means the cache
54 * page is being flushing to storage. FREE means the cache page is freed and
55 * should be skipped from flushing to storage. Please see
56 * null_make_cache_space
57 */
58 struct nullb_page {
59 struct page *page;
60 DECLARE_BITMAP(bitmap, MAP_SZ);
61 };
62 #define NULLB_PAGE_LOCK (MAP_SZ - 1)
63 #define NULLB_PAGE_FREE (MAP_SZ - 2)
64
65 static LIST_HEAD(nullb_list);
66 static struct mutex lock;
67 static int null_major;
68 static DEFINE_IDA(nullb_indexes);
69 static struct blk_mq_tag_set tag_set;
70
71 enum {
72 NULL_IRQ_NONE = 0,
73 NULL_IRQ_SOFTIRQ = 1,
74 NULL_IRQ_TIMER = 2,
75 };
76
77 enum {
78 NULL_Q_BIO = 0,
79 NULL_Q_RQ = 1,
80 NULL_Q_MQ = 2,
81 };
82
83 static bool g_virt_boundary = false;
84 module_param_named(virt_boundary, g_virt_boundary, bool, 0444);
85 MODULE_PARM_DESC(virt_boundary, "Require a virtual boundary for the device. Default: False");
86
87 static int g_no_sched;
88 module_param_named(no_sched, g_no_sched, int, 0444);
89 MODULE_PARM_DESC(no_sched, "No io scheduler");
90
91 static int g_submit_queues = 1;
92 module_param_named(submit_queues, g_submit_queues, int, 0444);
93 MODULE_PARM_DESC(submit_queues, "Number of submission queues");
94
95 static int g_poll_queues = 1;
96 module_param_named(poll_queues, g_poll_queues, int, 0444);
97 MODULE_PARM_DESC(poll_queues, "Number of IOPOLL submission queues");
98
99 static int g_home_node = NUMA_NO_NODE;
100 module_param_named(home_node, g_home_node, int, 0444);
101 MODULE_PARM_DESC(home_node, "Home node for the device");
102
103 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
104 /*
105 * For more details about fault injection, please refer to
106 * Documentation/fault-injection/fault-injection.rst.
107 */
108 static char g_timeout_str[80];
109 module_param_string(timeout, g_timeout_str, sizeof(g_timeout_str), 0444);
110 MODULE_PARM_DESC(timeout, "Fault injection. timeout=<interval>,<probability>,<space>,<times>");
111
112 static char g_requeue_str[80];
113 module_param_string(requeue, g_requeue_str, sizeof(g_requeue_str), 0444);
114 MODULE_PARM_DESC(requeue, "Fault injection. requeue=<interval>,<probability>,<space>,<times>");
115
116 static char g_init_hctx_str[80];
117 module_param_string(init_hctx, g_init_hctx_str, sizeof(g_init_hctx_str), 0444);
118 MODULE_PARM_DESC(init_hctx, "Fault injection to fail hctx init. init_hctx=<interval>,<probability>,<space>,<times>");
119 #endif
120
121 static int g_queue_mode = NULL_Q_MQ;
122
null_param_store_val(const char * str,int * val,int min,int max)123 static int null_param_store_val(const char *str, int *val, int min, int max)
124 {
125 int ret, new_val;
126
127 ret = kstrtoint(str, 10, &new_val);
128 if (ret)
129 return -EINVAL;
130
131 if (new_val < min || new_val > max)
132 return -EINVAL;
133
134 *val = new_val;
135 return 0;
136 }
137
null_set_queue_mode(const char * str,const struct kernel_param * kp)138 static int null_set_queue_mode(const char *str, const struct kernel_param *kp)
139 {
140 return null_param_store_val(str, &g_queue_mode, NULL_Q_BIO, NULL_Q_MQ);
141 }
142
143 static const struct kernel_param_ops null_queue_mode_param_ops = {
144 .set = null_set_queue_mode,
145 .get = param_get_int,
146 };
147
148 device_param_cb(queue_mode, &null_queue_mode_param_ops, &g_queue_mode, 0444);
149 MODULE_PARM_DESC(queue_mode, "Block interface to use (0=bio,1=rq,2=multiqueue)");
150
151 static int g_gb = 250;
152 module_param_named(gb, g_gb, int, 0444);
153 MODULE_PARM_DESC(gb, "Size in GB");
154
155 static int g_bs = 512;
156 module_param_named(bs, g_bs, int, 0444);
157 MODULE_PARM_DESC(bs, "Block size (in bytes)");
158
159 static int g_max_sectors;
160 module_param_named(max_sectors, g_max_sectors, int, 0444);
161 MODULE_PARM_DESC(max_sectors, "Maximum size of a command (in 512B sectors)");
162
163 static unsigned int nr_devices = 1;
164 module_param(nr_devices, uint, 0444);
165 MODULE_PARM_DESC(nr_devices, "Number of devices to register");
166
167 static bool g_blocking;
168 module_param_named(blocking, g_blocking, bool, 0444);
169 MODULE_PARM_DESC(blocking, "Register as a blocking blk-mq driver device");
170
171 static bool shared_tags;
172 module_param(shared_tags, bool, 0444);
173 MODULE_PARM_DESC(shared_tags, "Share tag set between devices for blk-mq");
174
175 static bool g_shared_tag_bitmap;
176 module_param_named(shared_tag_bitmap, g_shared_tag_bitmap, bool, 0444);
177 MODULE_PARM_DESC(shared_tag_bitmap, "Use shared tag bitmap for all submission queues for blk-mq");
178
179 static int g_irqmode = NULL_IRQ_SOFTIRQ;
180
null_set_irqmode(const char * str,const struct kernel_param * kp)181 static int null_set_irqmode(const char *str, const struct kernel_param *kp)
182 {
183 return null_param_store_val(str, &g_irqmode, NULL_IRQ_NONE,
184 NULL_IRQ_TIMER);
185 }
186
187 static const struct kernel_param_ops null_irqmode_param_ops = {
188 .set = null_set_irqmode,
189 .get = param_get_int,
190 };
191
192 device_param_cb(irqmode, &null_irqmode_param_ops, &g_irqmode, 0444);
193 MODULE_PARM_DESC(irqmode, "IRQ completion handler. 0-none, 1-softirq, 2-timer");
194
195 static unsigned long g_completion_nsec = 10000;
196 module_param_named(completion_nsec, g_completion_nsec, ulong, 0444);
197 MODULE_PARM_DESC(completion_nsec, "Time in ns to complete a request in hardware. Default: 10,000ns");
198
199 static int g_hw_queue_depth = 64;
200 module_param_named(hw_queue_depth, g_hw_queue_depth, int, 0444);
201 MODULE_PARM_DESC(hw_queue_depth, "Queue depth for each hardware queue. Default: 64");
202
203 static bool g_use_per_node_hctx;
204 module_param_named(use_per_node_hctx, g_use_per_node_hctx, bool, 0444);
205 MODULE_PARM_DESC(use_per_node_hctx, "Use per-node allocation for hardware context queues. Default: false");
206
207 static bool g_zoned;
208 module_param_named(zoned, g_zoned, bool, S_IRUGO);
209 MODULE_PARM_DESC(zoned, "Make device as a host-managed zoned block device. Default: false");
210
211 static unsigned long g_zone_size = 256;
212 module_param_named(zone_size, g_zone_size, ulong, S_IRUGO);
213 MODULE_PARM_DESC(zone_size, "Zone size in MB when block device is zoned. Must be power-of-two: Default: 256");
214
215 static unsigned long g_zone_capacity;
216 module_param_named(zone_capacity, g_zone_capacity, ulong, 0444);
217 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");
218
219 static unsigned int g_zone_nr_conv;
220 module_param_named(zone_nr_conv, g_zone_nr_conv, uint, 0444);
221 MODULE_PARM_DESC(zone_nr_conv, "Number of conventional zones when block device is zoned. Default: 0");
222
223 static unsigned int g_zone_max_open;
224 module_param_named(zone_max_open, g_zone_max_open, uint, 0444);
225 MODULE_PARM_DESC(zone_max_open, "Maximum number of open zones when block device is zoned. Default: 0 (no limit)");
226
227 static unsigned int g_zone_max_active;
228 module_param_named(zone_max_active, g_zone_max_active, uint, 0444);
229 MODULE_PARM_DESC(zone_max_active, "Maximum number of active zones when block device is zoned. Default: 0 (no limit)");
230
231 static struct nullb_device *null_alloc_dev(void);
232 static void null_free_dev(struct nullb_device *dev);
233 static void null_del_dev(struct nullb *nullb);
234 static int null_add_dev(struct nullb_device *dev);
235 static void null_free_device_storage(struct nullb_device *dev, bool is_cache);
236
to_nullb_device(struct config_item * item)237 static inline struct nullb_device *to_nullb_device(struct config_item *item)
238 {
239 return item ? container_of(item, struct nullb_device, item) : NULL;
240 }
241
nullb_device_uint_attr_show(unsigned int val,char * page)242 static inline ssize_t nullb_device_uint_attr_show(unsigned int val, char *page)
243 {
244 return snprintf(page, PAGE_SIZE, "%u\n", val);
245 }
246
nullb_device_ulong_attr_show(unsigned long val,char * page)247 static inline ssize_t nullb_device_ulong_attr_show(unsigned long val,
248 char *page)
249 {
250 return snprintf(page, PAGE_SIZE, "%lu\n", val);
251 }
252
nullb_device_bool_attr_show(bool val,char * page)253 static inline ssize_t nullb_device_bool_attr_show(bool val, char *page)
254 {
255 return snprintf(page, PAGE_SIZE, "%u\n", val);
256 }
257
nullb_device_uint_attr_store(unsigned int * val,const char * page,size_t count)258 static ssize_t nullb_device_uint_attr_store(unsigned int *val,
259 const char *page, size_t count)
260 {
261 unsigned int tmp;
262 int result;
263
264 result = kstrtouint(page, 0, &tmp);
265 if (result < 0)
266 return result;
267
268 *val = tmp;
269 return count;
270 }
271
nullb_device_ulong_attr_store(unsigned long * val,const char * page,size_t count)272 static ssize_t nullb_device_ulong_attr_store(unsigned long *val,
273 const char *page, size_t count)
274 {
275 int result;
276 unsigned long tmp;
277
278 result = kstrtoul(page, 0, &tmp);
279 if (result < 0)
280 return result;
281
282 *val = tmp;
283 return count;
284 }
285
nullb_device_bool_attr_store(bool * val,const char * page,size_t count)286 static ssize_t nullb_device_bool_attr_store(bool *val, const char *page,
287 size_t count)
288 {
289 bool tmp;
290 int result;
291
292 result = kstrtobool(page, &tmp);
293 if (result < 0)
294 return result;
295
296 *val = tmp;
297 return count;
298 }
299
300 /* The following macro should only be used with TYPE = {uint, ulong, bool}. */
301 #define NULLB_DEVICE_ATTR(NAME, TYPE, APPLY) \
302 static ssize_t \
303 nullb_device_##NAME##_show(struct config_item *item, char *page) \
304 { \
305 return nullb_device_##TYPE##_attr_show( \
306 to_nullb_device(item)->NAME, page); \
307 } \
308 static ssize_t \
309 nullb_device_##NAME##_store(struct config_item *item, const char *page, \
310 size_t count) \
311 { \
312 int (*apply_fn)(struct nullb_device *dev, TYPE new_value) = APPLY;\
313 struct nullb_device *dev = to_nullb_device(item); \
314 TYPE new_value = 0; \
315 int ret; \
316 \
317 ret = nullb_device_##TYPE##_attr_store(&new_value, page, count);\
318 if (ret < 0) \
319 return ret; \
320 if (apply_fn) \
321 ret = apply_fn(dev, new_value); \
322 else if (test_bit(NULLB_DEV_FL_CONFIGURED, &dev->flags)) \
323 ret = -EBUSY; \
324 if (ret < 0) \
325 return ret; \
326 dev->NAME = new_value; \
327 return count; \
328 } \
329 CONFIGFS_ATTR(nullb_device_, NAME);
330
nullb_update_nr_hw_queues(struct nullb_device * dev,unsigned int submit_queues,unsigned int poll_queues)331 static int nullb_update_nr_hw_queues(struct nullb_device *dev,
332 unsigned int submit_queues,
333 unsigned int poll_queues)
334
335 {
336 struct blk_mq_tag_set *set;
337 int ret, nr_hw_queues;
338
339 if (!dev->nullb)
340 return 0;
341
342 /*
343 * Make sure at least one queue exists for each of submit and poll.
344 */
345 if (!submit_queues || !poll_queues)
346 return -EINVAL;
347
348 /*
349 * Make sure that null_init_hctx() does not access nullb->queues[] past
350 * the end of that array.
351 */
352 if (submit_queues > nr_cpu_ids || poll_queues > g_poll_queues)
353 return -EINVAL;
354
355 /*
356 * Keep previous and new queue numbers in nullb_device for reference in
357 * the call back function null_map_queues().
358 */
359 dev->prev_submit_queues = dev->submit_queues;
360 dev->prev_poll_queues = dev->poll_queues;
361 dev->submit_queues = submit_queues;
362 dev->poll_queues = poll_queues;
363
364 set = dev->nullb->tag_set;
365 nr_hw_queues = submit_queues + poll_queues;
366 blk_mq_update_nr_hw_queues(set, nr_hw_queues);
367 ret = set->nr_hw_queues == nr_hw_queues ? 0 : -ENOMEM;
368
369 if (ret) {
370 /* on error, revert the queue numbers */
371 dev->submit_queues = dev->prev_submit_queues;
372 dev->poll_queues = dev->prev_poll_queues;
373 }
374
375 return ret;
376 }
377
nullb_apply_submit_queues(struct nullb_device * dev,unsigned int submit_queues)378 static int nullb_apply_submit_queues(struct nullb_device *dev,
379 unsigned int submit_queues)
380 {
381 return nullb_update_nr_hw_queues(dev, submit_queues, dev->poll_queues);
382 }
383
nullb_apply_poll_queues(struct nullb_device * dev,unsigned int poll_queues)384 static int nullb_apply_poll_queues(struct nullb_device *dev,
385 unsigned int poll_queues)
386 {
387 return nullb_update_nr_hw_queues(dev, dev->submit_queues, poll_queues);
388 }
389
390 NULLB_DEVICE_ATTR(size, ulong, NULL);
391 NULLB_DEVICE_ATTR(completion_nsec, ulong, NULL);
392 NULLB_DEVICE_ATTR(submit_queues, uint, nullb_apply_submit_queues);
393 NULLB_DEVICE_ATTR(poll_queues, uint, nullb_apply_poll_queues);
394 NULLB_DEVICE_ATTR(home_node, uint, NULL);
395 NULLB_DEVICE_ATTR(queue_mode, uint, NULL);
396 NULLB_DEVICE_ATTR(blocksize, uint, NULL);
397 NULLB_DEVICE_ATTR(max_sectors, uint, NULL);
398 NULLB_DEVICE_ATTR(irqmode, uint, NULL);
399 NULLB_DEVICE_ATTR(hw_queue_depth, uint, NULL);
400 NULLB_DEVICE_ATTR(index, uint, NULL);
401 NULLB_DEVICE_ATTR(blocking, bool, NULL);
402 NULLB_DEVICE_ATTR(use_per_node_hctx, bool, NULL);
403 NULLB_DEVICE_ATTR(memory_backed, bool, NULL);
404 NULLB_DEVICE_ATTR(discard, bool, NULL);
405 NULLB_DEVICE_ATTR(mbps, uint, NULL);
406 NULLB_DEVICE_ATTR(cache_size, ulong, NULL);
407 NULLB_DEVICE_ATTR(zoned, bool, NULL);
408 NULLB_DEVICE_ATTR(zone_size, ulong, NULL);
409 NULLB_DEVICE_ATTR(zone_capacity, ulong, NULL);
410 NULLB_DEVICE_ATTR(zone_nr_conv, uint, NULL);
411 NULLB_DEVICE_ATTR(zone_max_open, uint, NULL);
412 NULLB_DEVICE_ATTR(zone_max_active, uint, NULL);
413 NULLB_DEVICE_ATTR(virt_boundary, bool, NULL);
414
nullb_device_power_show(struct config_item * item,char * page)415 static ssize_t nullb_device_power_show(struct config_item *item, char *page)
416 {
417 return nullb_device_bool_attr_show(to_nullb_device(item)->power, page);
418 }
419
nullb_device_power_store(struct config_item * item,const char * page,size_t count)420 static ssize_t nullb_device_power_store(struct config_item *item,
421 const char *page, size_t count)
422 {
423 struct nullb_device *dev = to_nullb_device(item);
424 bool newp = false;
425 ssize_t ret;
426
427 ret = nullb_device_bool_attr_store(&newp, page, count);
428 if (ret < 0)
429 return ret;
430
431 if (!dev->power && newp) {
432 if (test_and_set_bit(NULLB_DEV_FL_UP, &dev->flags))
433 return count;
434 if (null_add_dev(dev)) {
435 clear_bit(NULLB_DEV_FL_UP, &dev->flags);
436 return -ENOMEM;
437 }
438
439 set_bit(NULLB_DEV_FL_CONFIGURED, &dev->flags);
440 dev->power = newp;
441 } else if (dev->power && !newp) {
442 if (test_and_clear_bit(NULLB_DEV_FL_UP, &dev->flags)) {
443 mutex_lock(&lock);
444 dev->power = newp;
445 null_del_dev(dev->nullb);
446 mutex_unlock(&lock);
447 }
448 clear_bit(NULLB_DEV_FL_CONFIGURED, &dev->flags);
449 }
450
451 return count;
452 }
453
454 CONFIGFS_ATTR(nullb_device_, power);
455
nullb_device_badblocks_show(struct config_item * item,char * page)456 static ssize_t nullb_device_badblocks_show(struct config_item *item, char *page)
457 {
458 struct nullb_device *t_dev = to_nullb_device(item);
459
460 return badblocks_show(&t_dev->badblocks, page, 0);
461 }
462
nullb_device_badblocks_store(struct config_item * item,const char * page,size_t count)463 static ssize_t nullb_device_badblocks_store(struct config_item *item,
464 const char *page, size_t count)
465 {
466 struct nullb_device *t_dev = to_nullb_device(item);
467 char *orig, *buf, *tmp;
468 u64 start, end;
469 int ret;
470
471 orig = kstrndup(page, count, GFP_KERNEL);
472 if (!orig)
473 return -ENOMEM;
474
475 buf = strstrip(orig);
476
477 ret = -EINVAL;
478 if (buf[0] != '+' && buf[0] != '-')
479 goto out;
480 tmp = strchr(&buf[1], '-');
481 if (!tmp)
482 goto out;
483 *tmp = '\0';
484 ret = kstrtoull(buf + 1, 0, &start);
485 if (ret)
486 goto out;
487 ret = kstrtoull(tmp + 1, 0, &end);
488 if (ret)
489 goto out;
490 ret = -EINVAL;
491 if (start > end)
492 goto out;
493 /* enable badblocks */
494 cmpxchg(&t_dev->badblocks.shift, -1, 0);
495 if (buf[0] == '+')
496 ret = badblocks_set(&t_dev->badblocks, start,
497 end - start + 1, 1);
498 else
499 ret = badblocks_clear(&t_dev->badblocks, start,
500 end - start + 1);
501 if (ret == 0)
502 ret = count;
503 out:
504 kfree(orig);
505 return ret;
506 }
507 CONFIGFS_ATTR(nullb_device_, badblocks);
508
509 static struct configfs_attribute *nullb_device_attrs[] = {
510 &nullb_device_attr_size,
511 &nullb_device_attr_completion_nsec,
512 &nullb_device_attr_submit_queues,
513 &nullb_device_attr_poll_queues,
514 &nullb_device_attr_home_node,
515 &nullb_device_attr_queue_mode,
516 &nullb_device_attr_blocksize,
517 &nullb_device_attr_max_sectors,
518 &nullb_device_attr_irqmode,
519 &nullb_device_attr_hw_queue_depth,
520 &nullb_device_attr_index,
521 &nullb_device_attr_blocking,
522 &nullb_device_attr_use_per_node_hctx,
523 &nullb_device_attr_power,
524 &nullb_device_attr_memory_backed,
525 &nullb_device_attr_discard,
526 &nullb_device_attr_mbps,
527 &nullb_device_attr_cache_size,
528 &nullb_device_attr_badblocks,
529 &nullb_device_attr_zoned,
530 &nullb_device_attr_zone_size,
531 &nullb_device_attr_zone_capacity,
532 &nullb_device_attr_zone_nr_conv,
533 &nullb_device_attr_zone_max_open,
534 &nullb_device_attr_zone_max_active,
535 &nullb_device_attr_virt_boundary,
536 NULL,
537 };
538
nullb_device_release(struct config_item * item)539 static void nullb_device_release(struct config_item *item)
540 {
541 struct nullb_device *dev = to_nullb_device(item);
542
543 null_free_device_storage(dev, false);
544 null_free_dev(dev);
545 }
546
547 static struct configfs_item_operations nullb_device_ops = {
548 .release = nullb_device_release,
549 };
550
551 static const struct config_item_type nullb_device_type = {
552 .ct_item_ops = &nullb_device_ops,
553 .ct_attrs = nullb_device_attrs,
554 .ct_owner = THIS_MODULE,
555 };
556
557 static struct
nullb_group_make_item(struct config_group * group,const char * name)558 config_item *nullb_group_make_item(struct config_group *group, const char *name)
559 {
560 struct nullb_device *dev;
561
562 dev = null_alloc_dev();
563 if (!dev)
564 return ERR_PTR(-ENOMEM);
565
566 config_item_init_type_name(&dev->item, name, &nullb_device_type);
567
568 return &dev->item;
569 }
570
571 static void
nullb_group_drop_item(struct config_group * group,struct config_item * item)572 nullb_group_drop_item(struct config_group *group, struct config_item *item)
573 {
574 struct nullb_device *dev = to_nullb_device(item);
575
576 if (test_and_clear_bit(NULLB_DEV_FL_UP, &dev->flags)) {
577 mutex_lock(&lock);
578 dev->power = false;
579 null_del_dev(dev->nullb);
580 mutex_unlock(&lock);
581 }
582
583 config_item_put(item);
584 }
585
memb_group_features_show(struct config_item * item,char * page)586 static ssize_t memb_group_features_show(struct config_item *item, char *page)
587 {
588 return snprintf(page, PAGE_SIZE,
589 "memory_backed,discard,bandwidth,cache,badblocks,zoned,zone_size,zone_capacity,zone_nr_conv,zone_max_open,zone_max_active,blocksize,max_sectors,virt_boundary\n");
590 }
591
592 CONFIGFS_ATTR_RO(memb_group_, features);
593
594 static struct configfs_attribute *nullb_group_attrs[] = {
595 &memb_group_attr_features,
596 NULL,
597 };
598
599 static struct configfs_group_operations nullb_group_ops = {
600 .make_item = nullb_group_make_item,
601 .drop_item = nullb_group_drop_item,
602 };
603
604 static const struct config_item_type nullb_group_type = {
605 .ct_group_ops = &nullb_group_ops,
606 .ct_attrs = nullb_group_attrs,
607 .ct_owner = THIS_MODULE,
608 };
609
610 static struct configfs_subsystem nullb_subsys = {
611 .su_group = {
612 .cg_item = {
613 .ci_namebuf = "nullb",
614 .ci_type = &nullb_group_type,
615 },
616 },
617 };
618
null_cache_active(struct nullb * nullb)619 static inline int null_cache_active(struct nullb *nullb)
620 {
621 return test_bit(NULLB_DEV_FL_CACHE, &nullb->dev->flags);
622 }
623
null_alloc_dev(void)624 static struct nullb_device *null_alloc_dev(void)
625 {
626 struct nullb_device *dev;
627
628 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
629 if (!dev)
630 return NULL;
631 INIT_RADIX_TREE(&dev->data, GFP_ATOMIC);
632 INIT_RADIX_TREE(&dev->cache, GFP_ATOMIC);
633 if (badblocks_init(&dev->badblocks, 0)) {
634 kfree(dev);
635 return NULL;
636 }
637
638 dev->size = g_gb * 1024;
639 dev->completion_nsec = g_completion_nsec;
640 dev->submit_queues = g_submit_queues;
641 dev->prev_submit_queues = g_submit_queues;
642 dev->poll_queues = g_poll_queues;
643 dev->prev_poll_queues = g_poll_queues;
644 dev->home_node = g_home_node;
645 dev->queue_mode = g_queue_mode;
646 dev->blocksize = g_bs;
647 dev->max_sectors = g_max_sectors;
648 dev->irqmode = g_irqmode;
649 dev->hw_queue_depth = g_hw_queue_depth;
650 dev->blocking = g_blocking;
651 dev->use_per_node_hctx = g_use_per_node_hctx;
652 dev->zoned = g_zoned;
653 dev->zone_size = g_zone_size;
654 dev->zone_capacity = g_zone_capacity;
655 dev->zone_nr_conv = g_zone_nr_conv;
656 dev->zone_max_open = g_zone_max_open;
657 dev->zone_max_active = g_zone_max_active;
658 dev->virt_boundary = g_virt_boundary;
659 return dev;
660 }
661
null_free_dev(struct nullb_device * dev)662 static void null_free_dev(struct nullb_device *dev)
663 {
664 if (!dev)
665 return;
666
667 null_free_zoned_dev(dev);
668 badblocks_exit(&dev->badblocks);
669 kfree(dev);
670 }
671
put_tag(struct nullb_queue * nq,unsigned int tag)672 static void put_tag(struct nullb_queue *nq, unsigned int tag)
673 {
674 clear_bit_unlock(tag, nq->tag_map);
675
676 if (waitqueue_active(&nq->wait))
677 wake_up(&nq->wait);
678 }
679
get_tag(struct nullb_queue * nq)680 static unsigned int get_tag(struct nullb_queue *nq)
681 {
682 unsigned int tag;
683
684 do {
685 tag = find_first_zero_bit(nq->tag_map, nq->queue_depth);
686 if (tag >= nq->queue_depth)
687 return -1U;
688 } while (test_and_set_bit_lock(tag, nq->tag_map));
689
690 return tag;
691 }
692
free_cmd(struct nullb_cmd * cmd)693 static void free_cmd(struct nullb_cmd *cmd)
694 {
695 put_tag(cmd->nq, cmd->tag);
696 }
697
698 static enum hrtimer_restart null_cmd_timer_expired(struct hrtimer *timer);
699
__alloc_cmd(struct nullb_queue * nq)700 static struct nullb_cmd *__alloc_cmd(struct nullb_queue *nq)
701 {
702 struct nullb_cmd *cmd;
703 unsigned int tag;
704
705 tag = get_tag(nq);
706 if (tag != -1U) {
707 cmd = &nq->cmds[tag];
708 cmd->tag = tag;
709 cmd->error = BLK_STS_OK;
710 cmd->nq = nq;
711 if (nq->dev->irqmode == NULL_IRQ_TIMER) {
712 hrtimer_init(&cmd->timer, CLOCK_MONOTONIC,
713 HRTIMER_MODE_REL);
714 cmd->timer.function = null_cmd_timer_expired;
715 }
716 return cmd;
717 }
718
719 return NULL;
720 }
721
alloc_cmd(struct nullb_queue * nq,int can_wait)722 static struct nullb_cmd *alloc_cmd(struct nullb_queue *nq, int can_wait)
723 {
724 struct nullb_cmd *cmd;
725 DEFINE_WAIT(wait);
726
727 cmd = __alloc_cmd(nq);
728 if (cmd || !can_wait)
729 return cmd;
730
731 do {
732 prepare_to_wait(&nq->wait, &wait, TASK_UNINTERRUPTIBLE);
733 cmd = __alloc_cmd(nq);
734 if (cmd)
735 break;
736
737 io_schedule();
738 } while (1);
739
740 finish_wait(&nq->wait, &wait);
741 return cmd;
742 }
743
end_cmd(struct nullb_cmd * cmd)744 static void end_cmd(struct nullb_cmd *cmd)
745 {
746 int queue_mode = cmd->nq->dev->queue_mode;
747
748 switch (queue_mode) {
749 case NULL_Q_MQ:
750 blk_mq_end_request(cmd->rq, cmd->error);
751 return;
752 case NULL_Q_BIO:
753 cmd->bio->bi_status = cmd->error;
754 bio_endio(cmd->bio);
755 break;
756 }
757
758 free_cmd(cmd);
759 }
760
null_cmd_timer_expired(struct hrtimer * timer)761 static enum hrtimer_restart null_cmd_timer_expired(struct hrtimer *timer)
762 {
763 end_cmd(container_of(timer, struct nullb_cmd, timer));
764
765 return HRTIMER_NORESTART;
766 }
767
null_cmd_end_timer(struct nullb_cmd * cmd)768 static void null_cmd_end_timer(struct nullb_cmd *cmd)
769 {
770 ktime_t kt = cmd->nq->dev->completion_nsec;
771
772 hrtimer_start(&cmd->timer, kt, HRTIMER_MODE_REL);
773 }
774
null_complete_rq(struct request * rq)775 static void null_complete_rq(struct request *rq)
776 {
777 end_cmd(blk_mq_rq_to_pdu(rq));
778 }
779
null_alloc_page(gfp_t gfp_flags)780 static struct nullb_page *null_alloc_page(gfp_t gfp_flags)
781 {
782 struct nullb_page *t_page;
783
784 t_page = kmalloc(sizeof(struct nullb_page), gfp_flags);
785 if (!t_page)
786 goto out;
787
788 t_page->page = alloc_pages(gfp_flags, 0);
789 if (!t_page->page)
790 goto out_freepage;
791
792 memset(t_page->bitmap, 0, sizeof(t_page->bitmap));
793 return t_page;
794 out_freepage:
795 kfree(t_page);
796 out:
797 return NULL;
798 }
799
null_free_page(struct nullb_page * t_page)800 static void null_free_page(struct nullb_page *t_page)
801 {
802 __set_bit(NULLB_PAGE_FREE, t_page->bitmap);
803 if (test_bit(NULLB_PAGE_LOCK, t_page->bitmap))
804 return;
805 __free_page(t_page->page);
806 kfree(t_page);
807 }
808
null_page_empty(struct nullb_page * page)809 static bool null_page_empty(struct nullb_page *page)
810 {
811 int size = MAP_SZ - 2;
812
813 return find_first_bit(page->bitmap, size) == size;
814 }
815
null_free_sector(struct nullb * nullb,sector_t sector,bool is_cache)816 static void null_free_sector(struct nullb *nullb, sector_t sector,
817 bool is_cache)
818 {
819 unsigned int sector_bit;
820 u64 idx;
821 struct nullb_page *t_page, *ret;
822 struct radix_tree_root *root;
823
824 root = is_cache ? &nullb->dev->cache : &nullb->dev->data;
825 idx = sector >> PAGE_SECTORS_SHIFT;
826 sector_bit = (sector & SECTOR_MASK);
827
828 t_page = radix_tree_lookup(root, idx);
829 if (t_page) {
830 __clear_bit(sector_bit, t_page->bitmap);
831
832 if (null_page_empty(t_page)) {
833 ret = radix_tree_delete_item(root, idx, t_page);
834 WARN_ON(ret != t_page);
835 null_free_page(ret);
836 if (is_cache)
837 nullb->dev->curr_cache -= PAGE_SIZE;
838 }
839 }
840 }
841
null_radix_tree_insert(struct nullb * nullb,u64 idx,struct nullb_page * t_page,bool is_cache)842 static struct nullb_page *null_radix_tree_insert(struct nullb *nullb, u64 idx,
843 struct nullb_page *t_page, bool is_cache)
844 {
845 struct radix_tree_root *root;
846
847 root = is_cache ? &nullb->dev->cache : &nullb->dev->data;
848
849 if (radix_tree_insert(root, idx, t_page)) {
850 null_free_page(t_page);
851 t_page = radix_tree_lookup(root, idx);
852 WARN_ON(!t_page || t_page->page->index != idx);
853 } else if (is_cache)
854 nullb->dev->curr_cache += PAGE_SIZE;
855
856 return t_page;
857 }
858
null_free_device_storage(struct nullb_device * dev,bool is_cache)859 static void null_free_device_storage(struct nullb_device *dev, bool is_cache)
860 {
861 unsigned long pos = 0;
862 int nr_pages;
863 struct nullb_page *ret, *t_pages[FREE_BATCH];
864 struct radix_tree_root *root;
865
866 root = is_cache ? &dev->cache : &dev->data;
867
868 do {
869 int i;
870
871 nr_pages = radix_tree_gang_lookup(root,
872 (void **)t_pages, pos, FREE_BATCH);
873
874 for (i = 0; i < nr_pages; i++) {
875 pos = t_pages[i]->page->index;
876 ret = radix_tree_delete_item(root, pos, t_pages[i]);
877 WARN_ON(ret != t_pages[i]);
878 null_free_page(ret);
879 }
880
881 pos++;
882 } while (nr_pages == FREE_BATCH);
883
884 if (is_cache)
885 dev->curr_cache = 0;
886 }
887
__null_lookup_page(struct nullb * nullb,sector_t sector,bool for_write,bool is_cache)888 static struct nullb_page *__null_lookup_page(struct nullb *nullb,
889 sector_t sector, bool for_write, bool is_cache)
890 {
891 unsigned int sector_bit;
892 u64 idx;
893 struct nullb_page *t_page;
894 struct radix_tree_root *root;
895
896 idx = sector >> PAGE_SECTORS_SHIFT;
897 sector_bit = (sector & SECTOR_MASK);
898
899 root = is_cache ? &nullb->dev->cache : &nullb->dev->data;
900 t_page = radix_tree_lookup(root, idx);
901 WARN_ON(t_page && t_page->page->index != idx);
902
903 if (t_page && (for_write || test_bit(sector_bit, t_page->bitmap)))
904 return t_page;
905
906 return NULL;
907 }
908
null_lookup_page(struct nullb * nullb,sector_t sector,bool for_write,bool ignore_cache)909 static struct nullb_page *null_lookup_page(struct nullb *nullb,
910 sector_t sector, bool for_write, bool ignore_cache)
911 {
912 struct nullb_page *page = NULL;
913
914 if (!ignore_cache)
915 page = __null_lookup_page(nullb, sector, for_write, true);
916 if (page)
917 return page;
918 return __null_lookup_page(nullb, sector, for_write, false);
919 }
920
null_insert_page(struct nullb * nullb,sector_t sector,bool ignore_cache)921 static struct nullb_page *null_insert_page(struct nullb *nullb,
922 sector_t sector, bool ignore_cache)
923 __releases(&nullb->lock)
924 __acquires(&nullb->lock)
925 {
926 u64 idx;
927 struct nullb_page *t_page;
928
929 t_page = null_lookup_page(nullb, sector, true, ignore_cache);
930 if (t_page)
931 return t_page;
932
933 spin_unlock_irq(&nullb->lock);
934
935 t_page = null_alloc_page(GFP_NOIO);
936 if (!t_page)
937 goto out_lock;
938
939 if (radix_tree_preload(GFP_NOIO))
940 goto out_freepage;
941
942 spin_lock_irq(&nullb->lock);
943 idx = sector >> PAGE_SECTORS_SHIFT;
944 t_page->page->index = idx;
945 t_page = null_radix_tree_insert(nullb, idx, t_page, !ignore_cache);
946 radix_tree_preload_end();
947
948 return t_page;
949 out_freepage:
950 null_free_page(t_page);
951 out_lock:
952 spin_lock_irq(&nullb->lock);
953 return null_lookup_page(nullb, sector, true, ignore_cache);
954 }
955
null_flush_cache_page(struct nullb * nullb,struct nullb_page * c_page)956 static int null_flush_cache_page(struct nullb *nullb, struct nullb_page *c_page)
957 {
958 int i;
959 unsigned int offset;
960 u64 idx;
961 struct nullb_page *t_page, *ret;
962 void *dst, *src;
963
964 idx = c_page->page->index;
965
966 t_page = null_insert_page(nullb, idx << PAGE_SECTORS_SHIFT, true);
967
968 __clear_bit(NULLB_PAGE_LOCK, c_page->bitmap);
969 if (test_bit(NULLB_PAGE_FREE, c_page->bitmap)) {
970 null_free_page(c_page);
971 if (t_page && null_page_empty(t_page)) {
972 ret = radix_tree_delete_item(&nullb->dev->data,
973 idx, t_page);
974 null_free_page(t_page);
975 }
976 return 0;
977 }
978
979 if (!t_page)
980 return -ENOMEM;
981
982 src = kmap_atomic(c_page->page);
983 dst = kmap_atomic(t_page->page);
984
985 for (i = 0; i < PAGE_SECTORS;
986 i += (nullb->dev->blocksize >> SECTOR_SHIFT)) {
987 if (test_bit(i, c_page->bitmap)) {
988 offset = (i << SECTOR_SHIFT);
989 memcpy(dst + offset, src + offset,
990 nullb->dev->blocksize);
991 __set_bit(i, t_page->bitmap);
992 }
993 }
994
995 kunmap_atomic(dst);
996 kunmap_atomic(src);
997
998 ret = radix_tree_delete_item(&nullb->dev->cache, idx, c_page);
999 null_free_page(ret);
1000 nullb->dev->curr_cache -= PAGE_SIZE;
1001
1002 return 0;
1003 }
1004
null_make_cache_space(struct nullb * nullb,unsigned long n)1005 static int null_make_cache_space(struct nullb *nullb, unsigned long n)
1006 {
1007 int i, err, nr_pages;
1008 struct nullb_page *c_pages[FREE_BATCH];
1009 unsigned long flushed = 0, one_round;
1010
1011 again:
1012 if ((nullb->dev->cache_size * 1024 * 1024) >
1013 nullb->dev->curr_cache + n || nullb->dev->curr_cache == 0)
1014 return 0;
1015
1016 nr_pages = radix_tree_gang_lookup(&nullb->dev->cache,
1017 (void **)c_pages, nullb->cache_flush_pos, FREE_BATCH);
1018 /*
1019 * nullb_flush_cache_page could unlock before using the c_pages. To
1020 * avoid race, we don't allow page free
1021 */
1022 for (i = 0; i < nr_pages; i++) {
1023 nullb->cache_flush_pos = c_pages[i]->page->index;
1024 /*
1025 * We found the page which is being flushed to disk by other
1026 * threads
1027 */
1028 if (test_bit(NULLB_PAGE_LOCK, c_pages[i]->bitmap))
1029 c_pages[i] = NULL;
1030 else
1031 __set_bit(NULLB_PAGE_LOCK, c_pages[i]->bitmap);
1032 }
1033
1034 one_round = 0;
1035 for (i = 0; i < nr_pages; i++) {
1036 if (c_pages[i] == NULL)
1037 continue;
1038 err = null_flush_cache_page(nullb, c_pages[i]);
1039 if (err)
1040 return err;
1041 one_round++;
1042 }
1043 flushed += one_round << PAGE_SHIFT;
1044
1045 if (n > flushed) {
1046 if (nr_pages == 0)
1047 nullb->cache_flush_pos = 0;
1048 if (one_round == 0) {
1049 /* give other threads a chance */
1050 spin_unlock_irq(&nullb->lock);
1051 spin_lock_irq(&nullb->lock);
1052 }
1053 goto again;
1054 }
1055 return 0;
1056 }
1057
copy_to_nullb(struct nullb * nullb,struct page * source,unsigned int off,sector_t sector,size_t n,bool is_fua)1058 static int copy_to_nullb(struct nullb *nullb, struct page *source,
1059 unsigned int off, sector_t sector, size_t n, bool is_fua)
1060 {
1061 size_t temp, count = 0;
1062 unsigned int offset;
1063 struct nullb_page *t_page;
1064 void *dst, *src;
1065
1066 while (count < n) {
1067 temp = min_t(size_t, nullb->dev->blocksize, n - count);
1068
1069 if (null_cache_active(nullb) && !is_fua)
1070 null_make_cache_space(nullb, PAGE_SIZE);
1071
1072 offset = (sector & SECTOR_MASK) << SECTOR_SHIFT;
1073 t_page = null_insert_page(nullb, sector,
1074 !null_cache_active(nullb) || is_fua);
1075 if (!t_page)
1076 return -ENOSPC;
1077
1078 src = kmap_atomic(source);
1079 dst = kmap_atomic(t_page->page);
1080 memcpy(dst + offset, src + off + count, temp);
1081 kunmap_atomic(dst);
1082 kunmap_atomic(src);
1083
1084 __set_bit(sector & SECTOR_MASK, t_page->bitmap);
1085
1086 if (is_fua)
1087 null_free_sector(nullb, sector, true);
1088
1089 count += temp;
1090 sector += temp >> SECTOR_SHIFT;
1091 }
1092 return 0;
1093 }
1094
copy_from_nullb(struct nullb * nullb,struct page * dest,unsigned int off,sector_t sector,size_t n)1095 static int copy_from_nullb(struct nullb *nullb, struct page *dest,
1096 unsigned int off, sector_t sector, size_t n)
1097 {
1098 size_t temp, count = 0;
1099 unsigned int offset;
1100 struct nullb_page *t_page;
1101 void *dst, *src;
1102
1103 while (count < n) {
1104 temp = min_t(size_t, nullb->dev->blocksize, n - count);
1105
1106 offset = (sector & SECTOR_MASK) << SECTOR_SHIFT;
1107 t_page = null_lookup_page(nullb, sector, false,
1108 !null_cache_active(nullb));
1109
1110 dst = kmap_atomic(dest);
1111 if (!t_page) {
1112 memset(dst + off + count, 0, temp);
1113 goto next;
1114 }
1115 src = kmap_atomic(t_page->page);
1116 memcpy(dst + off + count, src + offset, temp);
1117 kunmap_atomic(src);
1118 next:
1119 kunmap_atomic(dst);
1120
1121 count += temp;
1122 sector += temp >> SECTOR_SHIFT;
1123 }
1124 return 0;
1125 }
1126
nullb_fill_pattern(struct nullb * nullb,struct page * page,unsigned int len,unsigned int off)1127 static void nullb_fill_pattern(struct nullb *nullb, struct page *page,
1128 unsigned int len, unsigned int off)
1129 {
1130 void *dst;
1131
1132 dst = kmap_atomic(page);
1133 memset(dst + off, 0xFF, len);
1134 kunmap_atomic(dst);
1135 }
1136
null_handle_discard(struct nullb_device * dev,sector_t sector,sector_t nr_sectors)1137 blk_status_t null_handle_discard(struct nullb_device *dev,
1138 sector_t sector, sector_t nr_sectors)
1139 {
1140 struct nullb *nullb = dev->nullb;
1141 size_t n = nr_sectors << SECTOR_SHIFT;
1142 size_t temp;
1143
1144 spin_lock_irq(&nullb->lock);
1145 while (n > 0) {
1146 temp = min_t(size_t, n, dev->blocksize);
1147 null_free_sector(nullb, sector, false);
1148 if (null_cache_active(nullb))
1149 null_free_sector(nullb, sector, true);
1150 sector += temp >> SECTOR_SHIFT;
1151 n -= temp;
1152 }
1153 spin_unlock_irq(&nullb->lock);
1154
1155 return BLK_STS_OK;
1156 }
1157
null_handle_flush(struct nullb * nullb)1158 static int null_handle_flush(struct nullb *nullb)
1159 {
1160 int err;
1161
1162 if (!null_cache_active(nullb))
1163 return 0;
1164
1165 spin_lock_irq(&nullb->lock);
1166 while (true) {
1167 err = null_make_cache_space(nullb,
1168 nullb->dev->cache_size * 1024 * 1024);
1169 if (err || nullb->dev->curr_cache == 0)
1170 break;
1171 }
1172
1173 WARN_ON(!radix_tree_empty(&nullb->dev->cache));
1174 spin_unlock_irq(&nullb->lock);
1175 return err;
1176 }
1177
null_transfer(struct nullb * nullb,struct page * page,unsigned int len,unsigned int off,bool is_write,sector_t sector,bool is_fua)1178 static int null_transfer(struct nullb *nullb, struct page *page,
1179 unsigned int len, unsigned int off, bool is_write, sector_t sector,
1180 bool is_fua)
1181 {
1182 struct nullb_device *dev = nullb->dev;
1183 unsigned int valid_len = len;
1184 int err = 0;
1185
1186 if (!is_write) {
1187 if (dev->zoned)
1188 valid_len = null_zone_valid_read_len(nullb,
1189 sector, len);
1190
1191 if (valid_len) {
1192 err = copy_from_nullb(nullb, page, off,
1193 sector, valid_len);
1194 off += valid_len;
1195 len -= valid_len;
1196 }
1197
1198 if (len)
1199 nullb_fill_pattern(nullb, page, len, off);
1200 flush_dcache_page(page);
1201 } else {
1202 flush_dcache_page(page);
1203 err = copy_to_nullb(nullb, page, off, sector, len, is_fua);
1204 }
1205
1206 return err;
1207 }
1208
null_handle_rq(struct nullb_cmd * cmd)1209 static int null_handle_rq(struct nullb_cmd *cmd)
1210 {
1211 struct request *rq = cmd->rq;
1212 struct nullb *nullb = cmd->nq->dev->nullb;
1213 int err;
1214 unsigned int len;
1215 sector_t sector = blk_rq_pos(rq);
1216 struct req_iterator iter;
1217 struct bio_vec bvec;
1218
1219 spin_lock_irq(&nullb->lock);
1220 rq_for_each_segment(bvec, rq, iter) {
1221 len = bvec.bv_len;
1222 err = null_transfer(nullb, bvec.bv_page, len, bvec.bv_offset,
1223 op_is_write(req_op(rq)), sector,
1224 rq->cmd_flags & REQ_FUA);
1225 if (err) {
1226 spin_unlock_irq(&nullb->lock);
1227 return err;
1228 }
1229 sector += len >> SECTOR_SHIFT;
1230 }
1231 spin_unlock_irq(&nullb->lock);
1232
1233 return 0;
1234 }
1235
null_handle_bio(struct nullb_cmd * cmd)1236 static int null_handle_bio(struct nullb_cmd *cmd)
1237 {
1238 struct bio *bio = cmd->bio;
1239 struct nullb *nullb = cmd->nq->dev->nullb;
1240 int err;
1241 unsigned int len;
1242 sector_t sector = bio->bi_iter.bi_sector;
1243 struct bio_vec bvec;
1244 struct bvec_iter iter;
1245
1246 spin_lock_irq(&nullb->lock);
1247 bio_for_each_segment(bvec, bio, iter) {
1248 len = bvec.bv_len;
1249 err = null_transfer(nullb, bvec.bv_page, len, bvec.bv_offset,
1250 op_is_write(bio_op(bio)), sector,
1251 bio->bi_opf & REQ_FUA);
1252 if (err) {
1253 spin_unlock_irq(&nullb->lock);
1254 return err;
1255 }
1256 sector += len >> SECTOR_SHIFT;
1257 }
1258 spin_unlock_irq(&nullb->lock);
1259 return 0;
1260 }
1261
null_stop_queue(struct nullb * nullb)1262 static void null_stop_queue(struct nullb *nullb)
1263 {
1264 struct request_queue *q = nullb->q;
1265
1266 if (nullb->dev->queue_mode == NULL_Q_MQ)
1267 blk_mq_stop_hw_queues(q);
1268 }
1269
null_restart_queue_async(struct nullb * nullb)1270 static void null_restart_queue_async(struct nullb *nullb)
1271 {
1272 struct request_queue *q = nullb->q;
1273
1274 if (nullb->dev->queue_mode == NULL_Q_MQ)
1275 blk_mq_start_stopped_hw_queues(q, true);
1276 }
1277
null_handle_throttled(struct nullb_cmd * cmd)1278 static inline blk_status_t null_handle_throttled(struct nullb_cmd *cmd)
1279 {
1280 struct nullb_device *dev = cmd->nq->dev;
1281 struct nullb *nullb = dev->nullb;
1282 blk_status_t sts = BLK_STS_OK;
1283 struct request *rq = cmd->rq;
1284
1285 if (!hrtimer_active(&nullb->bw_timer))
1286 hrtimer_restart(&nullb->bw_timer);
1287
1288 if (atomic_long_sub_return(blk_rq_bytes(rq), &nullb->cur_bytes) < 0) {
1289 null_stop_queue(nullb);
1290 /* race with timer */
1291 if (atomic_long_read(&nullb->cur_bytes) > 0)
1292 null_restart_queue_async(nullb);
1293 /* requeue request */
1294 sts = BLK_STS_DEV_RESOURCE;
1295 }
1296 return sts;
1297 }
1298
null_handle_badblocks(struct nullb_cmd * cmd,sector_t sector,sector_t nr_sectors)1299 static inline blk_status_t null_handle_badblocks(struct nullb_cmd *cmd,
1300 sector_t sector,
1301 sector_t nr_sectors)
1302 {
1303 struct badblocks *bb = &cmd->nq->dev->badblocks;
1304 sector_t first_bad;
1305 int bad_sectors;
1306
1307 if (badblocks_check(bb, sector, nr_sectors, &first_bad, &bad_sectors))
1308 return BLK_STS_IOERR;
1309
1310 return BLK_STS_OK;
1311 }
1312
null_handle_memory_backed(struct nullb_cmd * cmd,enum req_opf op,sector_t sector,sector_t nr_sectors)1313 static inline blk_status_t null_handle_memory_backed(struct nullb_cmd *cmd,
1314 enum req_opf op,
1315 sector_t sector,
1316 sector_t nr_sectors)
1317 {
1318 struct nullb_device *dev = cmd->nq->dev;
1319 int err;
1320
1321 if (op == REQ_OP_DISCARD)
1322 return null_handle_discard(dev, sector, nr_sectors);
1323
1324 if (dev->queue_mode == NULL_Q_BIO)
1325 err = null_handle_bio(cmd);
1326 else
1327 err = null_handle_rq(cmd);
1328
1329 return errno_to_blk_status(err);
1330 }
1331
nullb_zero_read_cmd_buffer(struct nullb_cmd * cmd)1332 static void nullb_zero_read_cmd_buffer(struct nullb_cmd *cmd)
1333 {
1334 struct nullb_device *dev = cmd->nq->dev;
1335 struct bio *bio;
1336
1337 if (dev->memory_backed)
1338 return;
1339
1340 if (dev->queue_mode == NULL_Q_BIO && bio_op(cmd->bio) == REQ_OP_READ) {
1341 zero_fill_bio(cmd->bio);
1342 } else if (req_op(cmd->rq) == REQ_OP_READ) {
1343 __rq_for_each_bio(bio, cmd->rq)
1344 zero_fill_bio(bio);
1345 }
1346 }
1347
nullb_complete_cmd(struct nullb_cmd * cmd)1348 static inline void nullb_complete_cmd(struct nullb_cmd *cmd)
1349 {
1350 /*
1351 * Since root privileges are required to configure the null_blk
1352 * driver, it is fine that this driver does not initialize the
1353 * data buffers of read commands. Zero-initialize these buffers
1354 * anyway if KMSAN is enabled to prevent that KMSAN complains
1355 * about null_blk not initializing read data buffers.
1356 */
1357 if (IS_ENABLED(CONFIG_KMSAN))
1358 nullb_zero_read_cmd_buffer(cmd);
1359
1360 /* Complete IO by inline, softirq or timer */
1361 switch (cmd->nq->dev->irqmode) {
1362 case NULL_IRQ_SOFTIRQ:
1363 switch (cmd->nq->dev->queue_mode) {
1364 case NULL_Q_MQ:
1365 if (likely(!blk_should_fake_timeout(cmd->rq->q)))
1366 blk_mq_complete_request(cmd->rq);
1367 break;
1368 case NULL_Q_BIO:
1369 /*
1370 * XXX: no proper submitting cpu information available.
1371 */
1372 end_cmd(cmd);
1373 break;
1374 }
1375 break;
1376 case NULL_IRQ_NONE:
1377 end_cmd(cmd);
1378 break;
1379 case NULL_IRQ_TIMER:
1380 null_cmd_end_timer(cmd);
1381 break;
1382 }
1383 }
1384
null_process_cmd(struct nullb_cmd * cmd,enum req_opf op,sector_t sector,unsigned int nr_sectors)1385 blk_status_t null_process_cmd(struct nullb_cmd *cmd,
1386 enum req_opf op, sector_t sector,
1387 unsigned int nr_sectors)
1388 {
1389 struct nullb_device *dev = cmd->nq->dev;
1390 blk_status_t ret;
1391
1392 if (dev->badblocks.shift != -1) {
1393 ret = null_handle_badblocks(cmd, sector, nr_sectors);
1394 if (ret != BLK_STS_OK)
1395 return ret;
1396 }
1397
1398 if (dev->memory_backed)
1399 return null_handle_memory_backed(cmd, op, sector, nr_sectors);
1400
1401 return BLK_STS_OK;
1402 }
1403
null_handle_cmd(struct nullb_cmd * cmd,sector_t sector,sector_t nr_sectors,enum req_opf op)1404 static blk_status_t null_handle_cmd(struct nullb_cmd *cmd, sector_t sector,
1405 sector_t nr_sectors, enum req_opf op)
1406 {
1407 struct nullb_device *dev = cmd->nq->dev;
1408 struct nullb *nullb = dev->nullb;
1409 blk_status_t sts;
1410
1411 if (test_bit(NULLB_DEV_FL_THROTTLED, &dev->flags)) {
1412 sts = null_handle_throttled(cmd);
1413 if (sts != BLK_STS_OK)
1414 return sts;
1415 }
1416
1417 if (op == REQ_OP_FLUSH) {
1418 cmd->error = errno_to_blk_status(null_handle_flush(nullb));
1419 goto out;
1420 }
1421
1422 if (dev->zoned)
1423 sts = null_process_zoned_cmd(cmd, op, sector, nr_sectors);
1424 else
1425 sts = null_process_cmd(cmd, op, sector, nr_sectors);
1426
1427 /* Do not overwrite errors (e.g. timeout errors) */
1428 if (cmd->error == BLK_STS_OK)
1429 cmd->error = sts;
1430
1431 out:
1432 nullb_complete_cmd(cmd);
1433 return BLK_STS_OK;
1434 }
1435
nullb_bwtimer_fn(struct hrtimer * timer)1436 static enum hrtimer_restart nullb_bwtimer_fn(struct hrtimer *timer)
1437 {
1438 struct nullb *nullb = container_of(timer, struct nullb, bw_timer);
1439 ktime_t timer_interval = ktime_set(0, TIMER_INTERVAL);
1440 unsigned int mbps = nullb->dev->mbps;
1441
1442 if (atomic_long_read(&nullb->cur_bytes) == mb_per_tick(mbps))
1443 return HRTIMER_NORESTART;
1444
1445 atomic_long_set(&nullb->cur_bytes, mb_per_tick(mbps));
1446 null_restart_queue_async(nullb);
1447
1448 hrtimer_forward_now(&nullb->bw_timer, timer_interval);
1449
1450 return HRTIMER_RESTART;
1451 }
1452
nullb_setup_bwtimer(struct nullb * nullb)1453 static void nullb_setup_bwtimer(struct nullb *nullb)
1454 {
1455 ktime_t timer_interval = ktime_set(0, TIMER_INTERVAL);
1456
1457 hrtimer_init(&nullb->bw_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
1458 nullb->bw_timer.function = nullb_bwtimer_fn;
1459 atomic_long_set(&nullb->cur_bytes, mb_per_tick(nullb->dev->mbps));
1460 hrtimer_start(&nullb->bw_timer, timer_interval, HRTIMER_MODE_REL);
1461 }
1462
nullb_to_queue(struct nullb * nullb)1463 static struct nullb_queue *nullb_to_queue(struct nullb *nullb)
1464 {
1465 int index = 0;
1466
1467 if (nullb->nr_queues != 1)
1468 index = raw_smp_processor_id() / ((nr_cpu_ids + nullb->nr_queues - 1) / nullb->nr_queues);
1469
1470 return &nullb->queues[index];
1471 }
1472
null_submit_bio(struct bio * bio)1473 static void null_submit_bio(struct bio *bio)
1474 {
1475 sector_t sector = bio->bi_iter.bi_sector;
1476 sector_t nr_sectors = bio_sectors(bio);
1477 struct nullb *nullb = bio->bi_bdev->bd_disk->private_data;
1478 struct nullb_queue *nq = nullb_to_queue(nullb);
1479 struct nullb_cmd *cmd;
1480
1481 cmd = alloc_cmd(nq, 1);
1482 cmd->bio = bio;
1483
1484 null_handle_cmd(cmd, sector, nr_sectors, bio_op(bio));
1485 }
1486
should_timeout_request(struct request * rq)1487 static bool should_timeout_request(struct request *rq)
1488 {
1489 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
1490 if (g_timeout_str[0])
1491 return should_fail(&null_timeout_attr, 1);
1492 #endif
1493 return false;
1494 }
1495
should_requeue_request(struct request * rq)1496 static bool should_requeue_request(struct request *rq)
1497 {
1498 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
1499 if (g_requeue_str[0])
1500 return should_fail(&null_requeue_attr, 1);
1501 #endif
1502 return false;
1503 }
1504
null_map_queues(struct blk_mq_tag_set * set)1505 static int null_map_queues(struct blk_mq_tag_set *set)
1506 {
1507 struct nullb *nullb = set->driver_data;
1508 int i, qoff;
1509 unsigned int submit_queues = g_submit_queues;
1510 unsigned int poll_queues = g_poll_queues;
1511
1512 if (nullb) {
1513 struct nullb_device *dev = nullb->dev;
1514
1515 /*
1516 * Refer nr_hw_queues of the tag set to check if the expected
1517 * number of hardware queues are prepared. If block layer failed
1518 * to prepare them, use previous numbers of submit queues and
1519 * poll queues to map queues.
1520 */
1521 if (set->nr_hw_queues ==
1522 dev->submit_queues + dev->poll_queues) {
1523 submit_queues = dev->submit_queues;
1524 poll_queues = dev->poll_queues;
1525 } else if (set->nr_hw_queues ==
1526 dev->prev_submit_queues + dev->prev_poll_queues) {
1527 submit_queues = dev->prev_submit_queues;
1528 poll_queues = dev->prev_poll_queues;
1529 } else {
1530 pr_warn("tag set has unexpected nr_hw_queues: %d\n",
1531 set->nr_hw_queues);
1532 return -EINVAL;
1533 }
1534 }
1535
1536 for (i = 0, qoff = 0; i < set->nr_maps; i++) {
1537 struct blk_mq_queue_map *map = &set->map[i];
1538
1539 switch (i) {
1540 case HCTX_TYPE_DEFAULT:
1541 map->nr_queues = submit_queues;
1542 break;
1543 case HCTX_TYPE_READ:
1544 map->nr_queues = 0;
1545 continue;
1546 case HCTX_TYPE_POLL:
1547 map->nr_queues = poll_queues;
1548 break;
1549 }
1550 map->queue_offset = qoff;
1551 qoff += map->nr_queues;
1552 blk_mq_map_queues(map);
1553 }
1554
1555 return 0;
1556 }
1557
null_poll(struct blk_mq_hw_ctx * hctx,struct io_comp_batch * iob)1558 static int null_poll(struct blk_mq_hw_ctx *hctx, struct io_comp_batch *iob)
1559 {
1560 struct nullb_queue *nq = hctx->driver_data;
1561 LIST_HEAD(list);
1562 int nr = 0;
1563
1564 spin_lock(&nq->poll_lock);
1565 list_splice_init(&nq->poll_list, &list);
1566 spin_unlock(&nq->poll_lock);
1567
1568 while (!list_empty(&list)) {
1569 struct nullb_cmd *cmd;
1570 struct request *req;
1571
1572 req = list_first_entry(&list, struct request, queuelist);
1573 list_del_init(&req->queuelist);
1574 cmd = blk_mq_rq_to_pdu(req);
1575 cmd->error = null_process_cmd(cmd, req_op(req), blk_rq_pos(req),
1576 blk_rq_sectors(req));
1577 end_cmd(cmd);
1578 nr++;
1579 }
1580
1581 return nr;
1582 }
1583
null_timeout_rq(struct request * rq,bool res)1584 static enum blk_eh_timer_return null_timeout_rq(struct request *rq, bool res)
1585 {
1586 struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
1587 struct nullb_cmd *cmd = blk_mq_rq_to_pdu(rq);
1588
1589 pr_info("rq %p timed out\n", rq);
1590
1591 if (hctx->type == HCTX_TYPE_POLL) {
1592 struct nullb_queue *nq = hctx->driver_data;
1593
1594 spin_lock(&nq->poll_lock);
1595 list_del_init(&rq->queuelist);
1596 spin_unlock(&nq->poll_lock);
1597 }
1598
1599 /*
1600 * If the device is marked as blocking (i.e. memory backed or zoned
1601 * device), the submission path may be blocked waiting for resources
1602 * and cause real timeouts. For these real timeouts, the submission
1603 * path will complete the request using blk_mq_complete_request().
1604 * Only fake timeouts need to execute blk_mq_complete_request() here.
1605 */
1606 cmd->error = BLK_STS_TIMEOUT;
1607 if (cmd->fake_timeout)
1608 blk_mq_complete_request(rq);
1609 return BLK_EH_DONE;
1610 }
1611
null_queue_rq(struct blk_mq_hw_ctx * hctx,const struct blk_mq_queue_data * bd)1612 static blk_status_t null_queue_rq(struct blk_mq_hw_ctx *hctx,
1613 const struct blk_mq_queue_data *bd)
1614 {
1615 struct nullb_cmd *cmd = blk_mq_rq_to_pdu(bd->rq);
1616 struct nullb_queue *nq = hctx->driver_data;
1617 sector_t nr_sectors = blk_rq_sectors(bd->rq);
1618 sector_t sector = blk_rq_pos(bd->rq);
1619 const bool is_poll = hctx->type == HCTX_TYPE_POLL;
1620
1621 might_sleep_if(hctx->flags & BLK_MQ_F_BLOCKING);
1622
1623 if (!is_poll && nq->dev->irqmode == NULL_IRQ_TIMER) {
1624 hrtimer_init(&cmd->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
1625 cmd->timer.function = null_cmd_timer_expired;
1626 }
1627 cmd->rq = bd->rq;
1628 cmd->error = BLK_STS_OK;
1629 cmd->nq = nq;
1630 cmd->fake_timeout = should_timeout_request(bd->rq);
1631
1632 blk_mq_start_request(bd->rq);
1633
1634 if (should_requeue_request(bd->rq)) {
1635 /*
1636 * Alternate between hitting the core BUSY path, and the
1637 * driver driven requeue path
1638 */
1639 nq->requeue_selection++;
1640 if (nq->requeue_selection & 1)
1641 return BLK_STS_RESOURCE;
1642 else {
1643 blk_mq_requeue_request(bd->rq, true);
1644 return BLK_STS_OK;
1645 }
1646 }
1647
1648 if (is_poll) {
1649 spin_lock(&nq->poll_lock);
1650 list_add_tail(&bd->rq->queuelist, &nq->poll_list);
1651 spin_unlock(&nq->poll_lock);
1652 return BLK_STS_OK;
1653 }
1654 if (cmd->fake_timeout)
1655 return BLK_STS_OK;
1656
1657 return null_handle_cmd(cmd, sector, nr_sectors, req_op(bd->rq));
1658 }
1659
cleanup_queue(struct nullb_queue * nq)1660 static void cleanup_queue(struct nullb_queue *nq)
1661 {
1662 kfree(nq->tag_map);
1663 kfree(nq->cmds);
1664 }
1665
cleanup_queues(struct nullb * nullb)1666 static void cleanup_queues(struct nullb *nullb)
1667 {
1668 int i;
1669
1670 for (i = 0; i < nullb->nr_queues; i++)
1671 cleanup_queue(&nullb->queues[i]);
1672
1673 kfree(nullb->queues);
1674 }
1675
null_exit_hctx(struct blk_mq_hw_ctx * hctx,unsigned int hctx_idx)1676 static void null_exit_hctx(struct blk_mq_hw_ctx *hctx, unsigned int hctx_idx)
1677 {
1678 struct nullb_queue *nq = hctx->driver_data;
1679 struct nullb *nullb = nq->dev->nullb;
1680
1681 nullb->nr_queues--;
1682 }
1683
null_init_queue(struct nullb * nullb,struct nullb_queue * nq)1684 static void null_init_queue(struct nullb *nullb, struct nullb_queue *nq)
1685 {
1686 init_waitqueue_head(&nq->wait);
1687 nq->queue_depth = nullb->queue_depth;
1688 nq->dev = nullb->dev;
1689 INIT_LIST_HEAD(&nq->poll_list);
1690 spin_lock_init(&nq->poll_lock);
1691 }
1692
null_init_hctx(struct blk_mq_hw_ctx * hctx,void * driver_data,unsigned int hctx_idx)1693 static int null_init_hctx(struct blk_mq_hw_ctx *hctx, void *driver_data,
1694 unsigned int hctx_idx)
1695 {
1696 struct nullb *nullb = hctx->queue->queuedata;
1697 struct nullb_queue *nq;
1698
1699 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
1700 if (g_init_hctx_str[0] && should_fail(&null_init_hctx_attr, 1))
1701 return -EFAULT;
1702 #endif
1703
1704 nq = &nullb->queues[hctx_idx];
1705 hctx->driver_data = nq;
1706 null_init_queue(nullb, nq);
1707 nullb->nr_queues++;
1708
1709 return 0;
1710 }
1711
1712 static const struct blk_mq_ops null_mq_ops = {
1713 .queue_rq = null_queue_rq,
1714 .complete = null_complete_rq,
1715 .timeout = null_timeout_rq,
1716 .poll = null_poll,
1717 .map_queues = null_map_queues,
1718 .init_hctx = null_init_hctx,
1719 .exit_hctx = null_exit_hctx,
1720 };
1721
null_del_dev(struct nullb * nullb)1722 static void null_del_dev(struct nullb *nullb)
1723 {
1724 struct nullb_device *dev;
1725
1726 if (!nullb)
1727 return;
1728
1729 dev = nullb->dev;
1730
1731 ida_simple_remove(&nullb_indexes, nullb->index);
1732
1733 list_del_init(&nullb->list);
1734
1735 del_gendisk(nullb->disk);
1736
1737 if (test_bit(NULLB_DEV_FL_THROTTLED, &nullb->dev->flags)) {
1738 hrtimer_cancel(&nullb->bw_timer);
1739 atomic_long_set(&nullb->cur_bytes, LONG_MAX);
1740 null_restart_queue_async(nullb);
1741 }
1742
1743 blk_cleanup_disk(nullb->disk);
1744 if (dev->queue_mode == NULL_Q_MQ &&
1745 nullb->tag_set == &nullb->__tag_set)
1746 blk_mq_free_tag_set(nullb->tag_set);
1747 cleanup_queues(nullb);
1748 if (null_cache_active(nullb))
1749 null_free_device_storage(nullb->dev, true);
1750 kfree(nullb);
1751 dev->nullb = NULL;
1752 }
1753
null_config_discard(struct nullb * nullb)1754 static void null_config_discard(struct nullb *nullb)
1755 {
1756 if (nullb->dev->discard == false)
1757 return;
1758
1759 if (!nullb->dev->memory_backed) {
1760 nullb->dev->discard = false;
1761 pr_info("discard option is ignored without memory backing\n");
1762 return;
1763 }
1764
1765 if (nullb->dev->zoned) {
1766 nullb->dev->discard = false;
1767 pr_info("discard option is ignored in zoned mode\n");
1768 return;
1769 }
1770
1771 nullb->q->limits.discard_granularity = nullb->dev->blocksize;
1772 nullb->q->limits.discard_alignment = nullb->dev->blocksize;
1773 blk_queue_max_discard_sectors(nullb->q, UINT_MAX >> 9);
1774 blk_queue_flag_set(QUEUE_FLAG_DISCARD, nullb->q);
1775 }
1776
1777 static const struct block_device_operations null_bio_ops = {
1778 .owner = THIS_MODULE,
1779 .submit_bio = null_submit_bio,
1780 .report_zones = null_report_zones,
1781 };
1782
1783 static const struct block_device_operations null_rq_ops = {
1784 .owner = THIS_MODULE,
1785 .report_zones = null_report_zones,
1786 };
1787
setup_commands(struct nullb_queue * nq)1788 static int setup_commands(struct nullb_queue *nq)
1789 {
1790 struct nullb_cmd *cmd;
1791 int i, tag_size;
1792
1793 nq->cmds = kcalloc(nq->queue_depth, sizeof(*cmd), GFP_KERNEL);
1794 if (!nq->cmds)
1795 return -ENOMEM;
1796
1797 tag_size = ALIGN(nq->queue_depth, BITS_PER_LONG) / BITS_PER_LONG;
1798 nq->tag_map = kcalloc(tag_size, sizeof(unsigned long), GFP_KERNEL);
1799 if (!nq->tag_map) {
1800 kfree(nq->cmds);
1801 return -ENOMEM;
1802 }
1803
1804 for (i = 0; i < nq->queue_depth; i++) {
1805 cmd = &nq->cmds[i];
1806 cmd->tag = -1U;
1807 }
1808
1809 return 0;
1810 }
1811
setup_queues(struct nullb * nullb)1812 static int setup_queues(struct nullb *nullb)
1813 {
1814 int nqueues = nr_cpu_ids;
1815
1816 if (g_poll_queues)
1817 nqueues += g_poll_queues;
1818
1819 nullb->queues = kcalloc(nqueues, sizeof(struct nullb_queue),
1820 GFP_KERNEL);
1821 if (!nullb->queues)
1822 return -ENOMEM;
1823
1824 nullb->queue_depth = nullb->dev->hw_queue_depth;
1825 return 0;
1826 }
1827
init_driver_queues(struct nullb * nullb)1828 static int init_driver_queues(struct nullb *nullb)
1829 {
1830 struct nullb_queue *nq;
1831 int i, ret = 0;
1832
1833 for (i = 0; i < nullb->dev->submit_queues; i++) {
1834 nq = &nullb->queues[i];
1835
1836 null_init_queue(nullb, nq);
1837
1838 ret = setup_commands(nq);
1839 if (ret)
1840 return ret;
1841 nullb->nr_queues++;
1842 }
1843 return 0;
1844 }
1845
null_gendisk_register(struct nullb * nullb)1846 static int null_gendisk_register(struct nullb *nullb)
1847 {
1848 sector_t size = ((sector_t)nullb->dev->size * SZ_1M) >> SECTOR_SHIFT;
1849 struct gendisk *disk = nullb->disk;
1850
1851 set_capacity(disk, size);
1852
1853 disk->flags |= GENHD_FL_EXT_DEVT | GENHD_FL_SUPPRESS_PARTITION_INFO;
1854 disk->major = null_major;
1855 disk->first_minor = nullb->index;
1856 disk->minors = 1;
1857 if (queue_is_mq(nullb->q))
1858 disk->fops = &null_rq_ops;
1859 else
1860 disk->fops = &null_bio_ops;
1861 disk->private_data = nullb;
1862 strncpy(disk->disk_name, nullb->disk_name, DISK_NAME_LEN);
1863
1864 if (nullb->dev->zoned) {
1865 int ret = null_register_zoned_dev(nullb);
1866
1867 if (ret)
1868 return ret;
1869 }
1870
1871 return add_disk(disk);
1872 }
1873
null_init_tag_set(struct nullb * nullb,struct blk_mq_tag_set * set)1874 static int null_init_tag_set(struct nullb *nullb, struct blk_mq_tag_set *set)
1875 {
1876 int poll_queues;
1877
1878 set->ops = &null_mq_ops;
1879 set->nr_hw_queues = nullb ? nullb->dev->submit_queues :
1880 g_submit_queues;
1881 poll_queues = nullb ? nullb->dev->poll_queues : g_poll_queues;
1882 if (poll_queues)
1883 set->nr_hw_queues += poll_queues;
1884 set->queue_depth = nullb ? nullb->dev->hw_queue_depth :
1885 g_hw_queue_depth;
1886 set->numa_node = nullb ? nullb->dev->home_node : g_home_node;
1887 set->cmd_size = sizeof(struct nullb_cmd);
1888 set->flags = BLK_MQ_F_SHOULD_MERGE;
1889 if (g_no_sched)
1890 set->flags |= BLK_MQ_F_NO_SCHED;
1891 if (g_shared_tag_bitmap)
1892 set->flags |= BLK_MQ_F_TAG_HCTX_SHARED;
1893 set->driver_data = nullb;
1894 if (g_poll_queues)
1895 set->nr_maps = 3;
1896 else
1897 set->nr_maps = 1;
1898
1899 if ((nullb && nullb->dev->blocking) || g_blocking)
1900 set->flags |= BLK_MQ_F_BLOCKING;
1901
1902 return blk_mq_alloc_tag_set(set);
1903 }
1904
null_validate_conf(struct nullb_device * dev)1905 static int null_validate_conf(struct nullb_device *dev)
1906 {
1907 dev->blocksize = round_down(dev->blocksize, 512);
1908 dev->blocksize = clamp_t(unsigned int, dev->blocksize, 512, 4096);
1909
1910 if (dev->queue_mode == NULL_Q_MQ && dev->use_per_node_hctx) {
1911 if (dev->submit_queues != nr_online_nodes)
1912 dev->submit_queues = nr_online_nodes;
1913 } else if (dev->submit_queues > nr_cpu_ids)
1914 dev->submit_queues = nr_cpu_ids;
1915 else if (dev->submit_queues == 0)
1916 dev->submit_queues = 1;
1917 dev->prev_submit_queues = dev->submit_queues;
1918
1919 if (dev->poll_queues > g_poll_queues)
1920 dev->poll_queues = g_poll_queues;
1921 else if (dev->poll_queues == 0)
1922 dev->poll_queues = 1;
1923 dev->prev_poll_queues = dev->poll_queues;
1924
1925 dev->queue_mode = min_t(unsigned int, dev->queue_mode, NULL_Q_MQ);
1926 dev->irqmode = min_t(unsigned int, dev->irqmode, NULL_IRQ_TIMER);
1927
1928 /* Do memory allocation, so set blocking */
1929 if (dev->memory_backed)
1930 dev->blocking = true;
1931 else /* cache is meaningless */
1932 dev->cache_size = 0;
1933 dev->cache_size = min_t(unsigned long, ULONG_MAX / 1024 / 1024,
1934 dev->cache_size);
1935 dev->mbps = min_t(unsigned int, 1024 * 40, dev->mbps);
1936 /* can not stop a queue */
1937 if (dev->queue_mode == NULL_Q_BIO)
1938 dev->mbps = 0;
1939
1940 if (dev->zoned &&
1941 (!dev->zone_size || !is_power_of_2(dev->zone_size))) {
1942 pr_err("zone_size must be power-of-two\n");
1943 return -EINVAL;
1944 }
1945
1946 return 0;
1947 }
1948
1949 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
__null_setup_fault(struct fault_attr * attr,char * str)1950 static bool __null_setup_fault(struct fault_attr *attr, char *str)
1951 {
1952 if (!str[0])
1953 return true;
1954
1955 if (!setup_fault_attr(attr, str))
1956 return false;
1957
1958 attr->verbose = 0;
1959 return true;
1960 }
1961 #endif
1962
null_setup_fault(void)1963 static bool null_setup_fault(void)
1964 {
1965 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
1966 if (!__null_setup_fault(&null_timeout_attr, g_timeout_str))
1967 return false;
1968 if (!__null_setup_fault(&null_requeue_attr, g_requeue_str))
1969 return false;
1970 if (!__null_setup_fault(&null_init_hctx_attr, g_init_hctx_str))
1971 return false;
1972 #endif
1973 return true;
1974 }
1975
null_add_dev(struct nullb_device * dev)1976 static int null_add_dev(struct nullb_device *dev)
1977 {
1978 struct nullb *nullb;
1979 int rv;
1980
1981 rv = null_validate_conf(dev);
1982 if (rv)
1983 return rv;
1984
1985 nullb = kzalloc_node(sizeof(*nullb), GFP_KERNEL, dev->home_node);
1986 if (!nullb) {
1987 rv = -ENOMEM;
1988 goto out;
1989 }
1990 nullb->dev = dev;
1991 dev->nullb = nullb;
1992
1993 spin_lock_init(&nullb->lock);
1994
1995 rv = setup_queues(nullb);
1996 if (rv)
1997 goto out_free_nullb;
1998
1999 if (dev->queue_mode == NULL_Q_MQ) {
2000 if (shared_tags) {
2001 nullb->tag_set = &tag_set;
2002 rv = 0;
2003 } else {
2004 nullb->tag_set = &nullb->__tag_set;
2005 rv = null_init_tag_set(nullb, nullb->tag_set);
2006 }
2007
2008 if (rv)
2009 goto out_cleanup_queues;
2010
2011 if (!null_setup_fault())
2012 goto out_cleanup_tags;
2013
2014 nullb->tag_set->timeout = 5 * HZ;
2015 nullb->disk = blk_mq_alloc_disk(nullb->tag_set, nullb);
2016 if (IS_ERR(nullb->disk)) {
2017 rv = PTR_ERR(nullb->disk);
2018 goto out_cleanup_tags;
2019 }
2020 nullb->q = nullb->disk->queue;
2021 } else if (dev->queue_mode == NULL_Q_BIO) {
2022 rv = -ENOMEM;
2023 nullb->disk = blk_alloc_disk(nullb->dev->home_node);
2024 if (!nullb->disk)
2025 goto out_cleanup_queues;
2026
2027 nullb->q = nullb->disk->queue;
2028 rv = init_driver_queues(nullb);
2029 if (rv)
2030 goto out_cleanup_disk;
2031 }
2032
2033 if (dev->mbps) {
2034 set_bit(NULLB_DEV_FL_THROTTLED, &dev->flags);
2035 nullb_setup_bwtimer(nullb);
2036 }
2037
2038 if (dev->cache_size > 0) {
2039 set_bit(NULLB_DEV_FL_CACHE, &nullb->dev->flags);
2040 blk_queue_write_cache(nullb->q, true, true);
2041 }
2042
2043 if (dev->zoned) {
2044 rv = null_init_zoned_dev(dev, nullb->q);
2045 if (rv)
2046 goto out_cleanup_disk;
2047 }
2048
2049 nullb->q->queuedata = nullb;
2050 blk_queue_flag_set(QUEUE_FLAG_NONROT, nullb->q);
2051 blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, nullb->q);
2052
2053 mutex_lock(&lock);
2054 nullb->index = ida_simple_get(&nullb_indexes, 0, 0, GFP_KERNEL);
2055 dev->index = nullb->index;
2056 mutex_unlock(&lock);
2057
2058 blk_queue_logical_block_size(nullb->q, dev->blocksize);
2059 blk_queue_physical_block_size(nullb->q, dev->blocksize);
2060 if (!dev->max_sectors)
2061 dev->max_sectors = queue_max_hw_sectors(nullb->q);
2062 dev->max_sectors = min_t(unsigned int, dev->max_sectors,
2063 BLK_DEF_MAX_SECTORS);
2064 blk_queue_max_hw_sectors(nullb->q, dev->max_sectors);
2065
2066 if (dev->virt_boundary)
2067 blk_queue_virt_boundary(nullb->q, PAGE_SIZE - 1);
2068
2069 null_config_discard(nullb);
2070
2071 sprintf(nullb->disk_name, "nullb%d", nullb->index);
2072
2073 rv = null_gendisk_register(nullb);
2074 if (rv)
2075 goto out_cleanup_zone;
2076
2077 mutex_lock(&lock);
2078 list_add_tail(&nullb->list, &nullb_list);
2079 mutex_unlock(&lock);
2080
2081 return 0;
2082 out_cleanup_zone:
2083 null_free_zoned_dev(dev);
2084 out_cleanup_disk:
2085 blk_cleanup_disk(nullb->disk);
2086 out_cleanup_tags:
2087 if (dev->queue_mode == NULL_Q_MQ && nullb->tag_set == &nullb->__tag_set)
2088 blk_mq_free_tag_set(nullb->tag_set);
2089 out_cleanup_queues:
2090 cleanup_queues(nullb);
2091 out_free_nullb:
2092 kfree(nullb);
2093 dev->nullb = NULL;
2094 out:
2095 return rv;
2096 }
2097
null_init(void)2098 static int __init null_init(void)
2099 {
2100 int ret = 0;
2101 unsigned int i;
2102 struct nullb *nullb;
2103 struct nullb_device *dev;
2104
2105 if (g_bs > PAGE_SIZE) {
2106 pr_warn("invalid block size\n");
2107 pr_warn("defaults block size to %lu\n", PAGE_SIZE);
2108 g_bs = PAGE_SIZE;
2109 }
2110
2111 if (g_max_sectors > BLK_DEF_MAX_SECTORS) {
2112 pr_warn("invalid max sectors\n");
2113 pr_warn("defaults max sectors to %u\n", BLK_DEF_MAX_SECTORS);
2114 g_max_sectors = BLK_DEF_MAX_SECTORS;
2115 }
2116
2117 if (g_home_node != NUMA_NO_NODE && g_home_node >= nr_online_nodes) {
2118 pr_err("invalid home_node value\n");
2119 g_home_node = NUMA_NO_NODE;
2120 }
2121
2122 if (g_queue_mode == NULL_Q_RQ) {
2123 pr_err("legacy IO path no longer available\n");
2124 return -EINVAL;
2125 }
2126 if (g_queue_mode == NULL_Q_MQ && g_use_per_node_hctx) {
2127 if (g_submit_queues != nr_online_nodes) {
2128 pr_warn("submit_queues param is set to %u.\n",
2129 nr_online_nodes);
2130 g_submit_queues = nr_online_nodes;
2131 }
2132 } else if (g_submit_queues > nr_cpu_ids)
2133 g_submit_queues = nr_cpu_ids;
2134 else if (g_submit_queues <= 0)
2135 g_submit_queues = 1;
2136
2137 if (g_queue_mode == NULL_Q_MQ && shared_tags) {
2138 ret = null_init_tag_set(NULL, &tag_set);
2139 if (ret)
2140 return ret;
2141 }
2142
2143 config_group_init(&nullb_subsys.su_group);
2144 mutex_init(&nullb_subsys.su_mutex);
2145
2146 ret = configfs_register_subsystem(&nullb_subsys);
2147 if (ret)
2148 goto err_tagset;
2149
2150 mutex_init(&lock);
2151
2152 null_major = register_blkdev(0, "nullb");
2153 if (null_major < 0) {
2154 ret = null_major;
2155 goto err_conf;
2156 }
2157
2158 for (i = 0; i < nr_devices; i++) {
2159 dev = null_alloc_dev();
2160 if (!dev) {
2161 ret = -ENOMEM;
2162 goto err_dev;
2163 }
2164 ret = null_add_dev(dev);
2165 if (ret) {
2166 null_free_dev(dev);
2167 goto err_dev;
2168 }
2169 }
2170
2171 pr_info("module loaded\n");
2172 return 0;
2173
2174 err_dev:
2175 while (!list_empty(&nullb_list)) {
2176 nullb = list_entry(nullb_list.next, struct nullb, list);
2177 dev = nullb->dev;
2178 null_del_dev(nullb);
2179 null_free_dev(dev);
2180 }
2181 unregister_blkdev(null_major, "nullb");
2182 err_conf:
2183 configfs_unregister_subsystem(&nullb_subsys);
2184 err_tagset:
2185 if (g_queue_mode == NULL_Q_MQ && shared_tags)
2186 blk_mq_free_tag_set(&tag_set);
2187 return ret;
2188 }
2189
null_exit(void)2190 static void __exit null_exit(void)
2191 {
2192 struct nullb *nullb;
2193
2194 configfs_unregister_subsystem(&nullb_subsys);
2195
2196 unregister_blkdev(null_major, "nullb");
2197
2198 mutex_lock(&lock);
2199 while (!list_empty(&nullb_list)) {
2200 struct nullb_device *dev;
2201
2202 nullb = list_entry(nullb_list.next, struct nullb, list);
2203 dev = nullb->dev;
2204 null_del_dev(nullb);
2205 null_free_dev(dev);
2206 }
2207 mutex_unlock(&lock);
2208
2209 if (g_queue_mode == NULL_Q_MQ && shared_tags)
2210 blk_mq_free_tag_set(&tag_set);
2211 }
2212
2213 module_init(null_init);
2214 module_exit(null_exit);
2215
2216 MODULE_AUTHOR("Jens Axboe <axboe@kernel.dk>");
2217 MODULE_LICENSE("GPL");
2218