Commit | Line | Data |
---|---|---|
f2298c04 | 1 | #include <linux/module.h> |
fc1bc354 | 2 | |
f2298c04 JA |
3 | #include <linux/moduleparam.h> |
4 | #include <linux/sched.h> | |
5 | #include <linux/fs.h> | |
6 | #include <linux/blkdev.h> | |
7 | #include <linux/init.h> | |
8 | #include <linux/slab.h> | |
9 | #include <linux/blk-mq.h> | |
10 | #include <linux/hrtimer.h> | |
11 | ||
12 | struct nullb_cmd { | |
13 | struct list_head list; | |
14 | struct llist_node ll_list; | |
15 | struct call_single_data csd; | |
16 | struct request *rq; | |
17 | struct bio *bio; | |
18 | unsigned int tag; | |
19 | struct nullb_queue *nq; | |
20 | }; | |
21 | ||
22 | struct nullb_queue { | |
23 | unsigned long *tag_map; | |
24 | wait_queue_head_t wait; | |
25 | unsigned int queue_depth; | |
26 | ||
27 | struct nullb_cmd *cmds; | |
28 | }; | |
29 | ||
30 | struct nullb { | |
31 | struct list_head list; | |
32 | unsigned int index; | |
33 | struct request_queue *q; | |
34 | struct gendisk *disk; | |
24d2f903 | 35 | struct blk_mq_tag_set tag_set; |
f2298c04 JA |
36 | struct hrtimer timer; |
37 | unsigned int queue_depth; | |
38 | spinlock_t lock; | |
39 | ||
40 | struct nullb_queue *queues; | |
41 | unsigned int nr_queues; | |
42 | }; | |
43 | ||
44 | static LIST_HEAD(nullb_list); | |
45 | static struct mutex lock; | |
46 | static int null_major; | |
47 | static int nullb_indexes; | |
48 | ||
49 | struct completion_queue { | |
50 | struct llist_head list; | |
51 | struct hrtimer timer; | |
52 | }; | |
53 | ||
54 | /* | |
55 | * These are per-cpu for now, they will need to be configured by the | |
56 | * complete_queues parameter and appropriately mapped. | |
57 | */ | |
58 | static DEFINE_PER_CPU(struct completion_queue, completion_queues); | |
59 | ||
60 | enum { | |
61 | NULL_IRQ_NONE = 0, | |
62 | NULL_IRQ_SOFTIRQ = 1, | |
63 | NULL_IRQ_TIMER = 2, | |
ce2c350b | 64 | }; |
f2298c04 | 65 | |
ce2c350b | 66 | enum { |
f2298c04 JA |
67 | NULL_Q_BIO = 0, |
68 | NULL_Q_RQ = 1, | |
69 | NULL_Q_MQ = 2, | |
70 | }; | |
71 | ||
2d263a78 | 72 | static int submit_queues; |
f2298c04 JA |
73 | module_param(submit_queues, int, S_IRUGO); |
74 | MODULE_PARM_DESC(submit_queues, "Number of submission queues"); | |
75 | ||
76 | static int home_node = NUMA_NO_NODE; | |
77 | module_param(home_node, int, S_IRUGO); | |
78 | MODULE_PARM_DESC(home_node, "Home node for the device"); | |
79 | ||
80 | static int queue_mode = NULL_Q_MQ; | |
81 | module_param(queue_mode, int, S_IRUGO); | |
82 | MODULE_PARM_DESC(use_mq, "Use blk-mq interface (0=bio,1=rq,2=multiqueue)"); | |
83 | ||
84 | static int gb = 250; | |
85 | module_param(gb, int, S_IRUGO); | |
86 | MODULE_PARM_DESC(gb, "Size in GB"); | |
87 | ||
88 | static int bs = 512; | |
89 | module_param(bs, int, S_IRUGO); | |
90 | MODULE_PARM_DESC(bs, "Block size (in bytes)"); | |
91 | ||
92 | static int nr_devices = 2; | |
93 | module_param(nr_devices, int, S_IRUGO); | |
94 | MODULE_PARM_DESC(nr_devices, "Number of devices to register"); | |
95 | ||
96 | static int irqmode = NULL_IRQ_SOFTIRQ; | |
97 | module_param(irqmode, int, S_IRUGO); | |
98 | MODULE_PARM_DESC(irqmode, "IRQ completion handler. 0-none, 1-softirq, 2-timer"); | |
99 | ||
100 | static int completion_nsec = 10000; | |
101 | module_param(completion_nsec, int, S_IRUGO); | |
102 | MODULE_PARM_DESC(completion_nsec, "Time in ns to complete a request in hardware. Default: 10,000ns"); | |
103 | ||
104 | static int hw_queue_depth = 64; | |
105 | module_param(hw_queue_depth, int, S_IRUGO); | |
106 | MODULE_PARM_DESC(hw_queue_depth, "Queue depth for each hardware queue. Default: 64"); | |
107 | ||
20005244 | 108 | static bool use_per_node_hctx = false; |
f2298c04 | 109 | module_param(use_per_node_hctx, bool, S_IRUGO); |
20005244 | 110 | MODULE_PARM_DESC(use_per_node_hctx, "Use per-node allocation for hardware context queues. Default: false"); |
f2298c04 JA |
111 | |
112 | static void put_tag(struct nullb_queue *nq, unsigned int tag) | |
113 | { | |
114 | clear_bit_unlock(tag, nq->tag_map); | |
115 | ||
116 | if (waitqueue_active(&nq->wait)) | |
117 | wake_up(&nq->wait); | |
118 | } | |
119 | ||
120 | static unsigned int get_tag(struct nullb_queue *nq) | |
121 | { | |
122 | unsigned int tag; | |
123 | ||
124 | do { | |
125 | tag = find_first_zero_bit(nq->tag_map, nq->queue_depth); | |
126 | if (tag >= nq->queue_depth) | |
127 | return -1U; | |
128 | } while (test_and_set_bit_lock(tag, nq->tag_map)); | |
129 | ||
130 | return tag; | |
131 | } | |
132 | ||
133 | static void free_cmd(struct nullb_cmd *cmd) | |
134 | { | |
135 | put_tag(cmd->nq, cmd->tag); | |
136 | } | |
137 | ||
138 | static struct nullb_cmd *__alloc_cmd(struct nullb_queue *nq) | |
139 | { | |
140 | struct nullb_cmd *cmd; | |
141 | unsigned int tag; | |
142 | ||
143 | tag = get_tag(nq); | |
144 | if (tag != -1U) { | |
145 | cmd = &nq->cmds[tag]; | |
146 | cmd->tag = tag; | |
147 | cmd->nq = nq; | |
148 | return cmd; | |
149 | } | |
150 | ||
151 | return NULL; | |
152 | } | |
153 | ||
154 | static struct nullb_cmd *alloc_cmd(struct nullb_queue *nq, int can_wait) | |
155 | { | |
156 | struct nullb_cmd *cmd; | |
157 | DEFINE_WAIT(wait); | |
158 | ||
159 | cmd = __alloc_cmd(nq); | |
160 | if (cmd || !can_wait) | |
161 | return cmd; | |
162 | ||
163 | do { | |
164 | prepare_to_wait(&nq->wait, &wait, TASK_UNINTERRUPTIBLE); | |
165 | cmd = __alloc_cmd(nq); | |
166 | if (cmd) | |
167 | break; | |
168 | ||
169 | io_schedule(); | |
170 | } while (1); | |
171 | ||
172 | finish_wait(&nq->wait, &wait); | |
173 | return cmd; | |
174 | } | |
175 | ||
176 | static void end_cmd(struct nullb_cmd *cmd) | |
177 | { | |
ce2c350b CH |
178 | switch (queue_mode) { |
179 | case NULL_Q_MQ: | |
180 | blk_mq_end_io(cmd->rq, 0); | |
181 | return; | |
182 | case NULL_Q_RQ: | |
183 | INIT_LIST_HEAD(&cmd->rq->queuelist); | |
184 | blk_end_request_all(cmd->rq, 0); | |
185 | break; | |
186 | case NULL_Q_BIO: | |
f2298c04 | 187 | bio_endio(cmd->bio, 0); |
ce2c350b CH |
188 | break; |
189 | } | |
f2298c04 | 190 | |
ce2c350b | 191 | free_cmd(cmd); |
f2298c04 JA |
192 | } |
193 | ||
194 | static enum hrtimer_restart null_cmd_timer_expired(struct hrtimer *timer) | |
195 | { | |
196 | struct completion_queue *cq; | |
197 | struct llist_node *entry; | |
198 | struct nullb_cmd *cmd; | |
199 | ||
200 | cq = &per_cpu(completion_queues, smp_processor_id()); | |
201 | ||
202 | while ((entry = llist_del_all(&cq->list)) != NULL) { | |
d7790b92 | 203 | entry = llist_reverse_order(entry); |
f2298c04 JA |
204 | do { |
205 | cmd = container_of(entry, struct nullb_cmd, ll_list); | |
f2298c04 | 206 | entry = entry->next; |
fc27691f | 207 | end_cmd(cmd); |
f2298c04 JA |
208 | } while (entry); |
209 | } | |
210 | ||
211 | return HRTIMER_NORESTART; | |
212 | } | |
213 | ||
214 | static void null_cmd_end_timer(struct nullb_cmd *cmd) | |
215 | { | |
216 | struct completion_queue *cq = &per_cpu(completion_queues, get_cpu()); | |
217 | ||
218 | cmd->ll_list.next = NULL; | |
219 | if (llist_add(&cmd->ll_list, &cq->list)) { | |
220 | ktime_t kt = ktime_set(0, completion_nsec); | |
221 | ||
222 | hrtimer_start(&cq->timer, kt, HRTIMER_MODE_REL); | |
223 | } | |
224 | ||
225 | put_cpu(); | |
226 | } | |
227 | ||
228 | static void null_softirq_done_fn(struct request *rq) | |
229 | { | |
9d74e257 | 230 | end_cmd(blk_mq_rq_to_pdu(rq)); |
f2298c04 JA |
231 | } |
232 | ||
f2298c04 JA |
233 | static inline void null_handle_cmd(struct nullb_cmd *cmd) |
234 | { | |
235 | /* Complete IO by inline, softirq or timer */ | |
236 | switch (irqmode) { | |
f2298c04 | 237 | case NULL_IRQ_SOFTIRQ: |
ce2c350b CH |
238 | switch (queue_mode) { |
239 | case NULL_Q_MQ: | |
240 | blk_mq_complete_request(cmd->rq); | |
241 | break; | |
242 | case NULL_Q_RQ: | |
243 | blk_complete_request(cmd->rq); | |
244 | break; | |
245 | case NULL_Q_BIO: | |
246 | /* | |
247 | * XXX: no proper submitting cpu information available. | |
248 | */ | |
249 | end_cmd(cmd); | |
250 | break; | |
251 | } | |
252 | break; | |
253 | case NULL_IRQ_NONE: | |
f2298c04 | 254 | end_cmd(cmd); |
f2298c04 JA |
255 | break; |
256 | case NULL_IRQ_TIMER: | |
257 | null_cmd_end_timer(cmd); | |
258 | break; | |
259 | } | |
260 | } | |
261 | ||
262 | static struct nullb_queue *nullb_to_queue(struct nullb *nullb) | |
263 | { | |
264 | int index = 0; | |
265 | ||
266 | if (nullb->nr_queues != 1) | |
267 | index = raw_smp_processor_id() / ((nr_cpu_ids + nullb->nr_queues - 1) / nullb->nr_queues); | |
268 | ||
269 | return &nullb->queues[index]; | |
270 | } | |
271 | ||
272 | static void null_queue_bio(struct request_queue *q, struct bio *bio) | |
273 | { | |
274 | struct nullb *nullb = q->queuedata; | |
275 | struct nullb_queue *nq = nullb_to_queue(nullb); | |
276 | struct nullb_cmd *cmd; | |
277 | ||
278 | cmd = alloc_cmd(nq, 1); | |
279 | cmd->bio = bio; | |
280 | ||
281 | null_handle_cmd(cmd); | |
282 | } | |
283 | ||
284 | static int null_rq_prep_fn(struct request_queue *q, struct request *req) | |
285 | { | |
286 | struct nullb *nullb = q->queuedata; | |
287 | struct nullb_queue *nq = nullb_to_queue(nullb); | |
288 | struct nullb_cmd *cmd; | |
289 | ||
290 | cmd = alloc_cmd(nq, 0); | |
291 | if (cmd) { | |
292 | cmd->rq = req; | |
293 | req->special = cmd; | |
294 | return BLKPREP_OK; | |
295 | } | |
296 | ||
297 | return BLKPREP_DEFER; | |
298 | } | |
299 | ||
300 | static void null_request_fn(struct request_queue *q) | |
301 | { | |
302 | struct request *rq; | |
303 | ||
304 | while ((rq = blk_fetch_request(q)) != NULL) { | |
305 | struct nullb_cmd *cmd = rq->special; | |
306 | ||
307 | spin_unlock_irq(q->queue_lock); | |
308 | null_handle_cmd(cmd); | |
309 | spin_lock_irq(q->queue_lock); | |
310 | } | |
311 | } | |
312 | ||
313 | static int null_queue_rq(struct blk_mq_hw_ctx *hctx, struct request *rq) | |
314 | { | |
9d74e257 | 315 | struct nullb_cmd *cmd = blk_mq_rq_to_pdu(rq); |
f2298c04 JA |
316 | |
317 | cmd->rq = rq; | |
318 | cmd->nq = hctx->driver_data; | |
319 | ||
320 | null_handle_cmd(cmd); | |
321 | return BLK_MQ_RQ_QUEUE_OK; | |
322 | } | |
323 | ||
2d263a78 MB |
324 | static void null_init_queue(struct nullb *nullb, struct nullb_queue *nq) |
325 | { | |
326 | BUG_ON(!nullb); | |
327 | BUG_ON(!nq); | |
328 | ||
329 | init_waitqueue_head(&nq->wait); | |
330 | nq->queue_depth = nullb->queue_depth; | |
331 | } | |
332 | ||
f2298c04 JA |
333 | static int null_init_hctx(struct blk_mq_hw_ctx *hctx, void *data, |
334 | unsigned int index) | |
335 | { | |
336 | struct nullb *nullb = data; | |
337 | struct nullb_queue *nq = &nullb->queues[index]; | |
338 | ||
f2298c04 | 339 | hctx->driver_data = nq; |
2d263a78 MB |
340 | null_init_queue(nullb, nq); |
341 | nullb->nr_queues++; | |
f2298c04 JA |
342 | |
343 | return 0; | |
344 | } | |
345 | ||
346 | static struct blk_mq_ops null_mq_ops = { | |
347 | .queue_rq = null_queue_rq, | |
348 | .map_queue = blk_mq_map_queue, | |
349 | .init_hctx = null_init_hctx, | |
ce2c350b | 350 | .complete = null_softirq_done_fn, |
f2298c04 JA |
351 | }; |
352 | ||
353 | static void null_del_dev(struct nullb *nullb) | |
354 | { | |
355 | list_del_init(&nullb->list); | |
356 | ||
357 | del_gendisk(nullb->disk); | |
518d00b7 | 358 | blk_cleanup_queue(nullb->q); |
24d2f903 CH |
359 | if (queue_mode == NULL_Q_MQ) |
360 | blk_mq_free_tag_set(&nullb->tag_set); | |
f2298c04 JA |
361 | put_disk(nullb->disk); |
362 | kfree(nullb); | |
363 | } | |
364 | ||
365 | static int null_open(struct block_device *bdev, fmode_t mode) | |
366 | { | |
367 | return 0; | |
368 | } | |
369 | ||
370 | static void null_release(struct gendisk *disk, fmode_t mode) | |
371 | { | |
372 | } | |
373 | ||
374 | static const struct block_device_operations null_fops = { | |
375 | .owner = THIS_MODULE, | |
376 | .open = null_open, | |
377 | .release = null_release, | |
378 | }; | |
379 | ||
380 | static int setup_commands(struct nullb_queue *nq) | |
381 | { | |
382 | struct nullb_cmd *cmd; | |
383 | int i, tag_size; | |
384 | ||
385 | nq->cmds = kzalloc(nq->queue_depth * sizeof(*cmd), GFP_KERNEL); | |
386 | if (!nq->cmds) | |
2d263a78 | 387 | return -ENOMEM; |
f2298c04 JA |
388 | |
389 | tag_size = ALIGN(nq->queue_depth, BITS_PER_LONG) / BITS_PER_LONG; | |
390 | nq->tag_map = kzalloc(tag_size * sizeof(unsigned long), GFP_KERNEL); | |
391 | if (!nq->tag_map) { | |
392 | kfree(nq->cmds); | |
2d263a78 | 393 | return -ENOMEM; |
f2298c04 JA |
394 | } |
395 | ||
396 | for (i = 0; i < nq->queue_depth; i++) { | |
397 | cmd = &nq->cmds[i]; | |
398 | INIT_LIST_HEAD(&cmd->list); | |
399 | cmd->ll_list.next = NULL; | |
400 | cmd->tag = -1U; | |
401 | } | |
402 | ||
403 | return 0; | |
404 | } | |
405 | ||
406 | static void cleanup_queue(struct nullb_queue *nq) | |
407 | { | |
408 | kfree(nq->tag_map); | |
409 | kfree(nq->cmds); | |
410 | } | |
411 | ||
412 | static void cleanup_queues(struct nullb *nullb) | |
413 | { | |
414 | int i; | |
415 | ||
416 | for (i = 0; i < nullb->nr_queues; i++) | |
417 | cleanup_queue(&nullb->queues[i]); | |
418 | ||
419 | kfree(nullb->queues); | |
420 | } | |
421 | ||
422 | static int setup_queues(struct nullb *nullb) | |
423 | { | |
2d263a78 MB |
424 | nullb->queues = kzalloc(submit_queues * sizeof(struct nullb_queue), |
425 | GFP_KERNEL); | |
f2298c04 | 426 | if (!nullb->queues) |
2d263a78 | 427 | return -ENOMEM; |
f2298c04 JA |
428 | |
429 | nullb->nr_queues = 0; | |
430 | nullb->queue_depth = hw_queue_depth; | |
431 | ||
2d263a78 MB |
432 | return 0; |
433 | } | |
434 | ||
435 | static int init_driver_queues(struct nullb *nullb) | |
436 | { | |
437 | struct nullb_queue *nq; | |
438 | int i, ret = 0; | |
f2298c04 JA |
439 | |
440 | for (i = 0; i < submit_queues; i++) { | |
441 | nq = &nullb->queues[i]; | |
2d263a78 MB |
442 | |
443 | null_init_queue(nullb, nq); | |
444 | ||
445 | ret = setup_commands(nq); | |
446 | if (ret) | |
447 | goto err_queue; | |
f2298c04 JA |
448 | nullb->nr_queues++; |
449 | } | |
450 | ||
2d263a78 MB |
451 | return 0; |
452 | err_queue: | |
f2298c04 | 453 | cleanup_queues(nullb); |
2d263a78 | 454 | return ret; |
f2298c04 JA |
455 | } |
456 | ||
457 | static int null_add_dev(void) | |
458 | { | |
459 | struct gendisk *disk; | |
460 | struct nullb *nullb; | |
461 | sector_t size; | |
462 | ||
463 | nullb = kzalloc_node(sizeof(*nullb), GFP_KERNEL, home_node); | |
464 | if (!nullb) | |
24d2f903 | 465 | goto out; |
f2298c04 JA |
466 | |
467 | spin_lock_init(&nullb->lock); | |
468 | ||
57053d8c MB |
469 | if (queue_mode == NULL_Q_MQ && use_per_node_hctx) |
470 | submit_queues = nr_online_nodes; | |
471 | ||
f2298c04 | 472 | if (setup_queues(nullb)) |
24d2f903 | 473 | goto out_free_nullb; |
f2298c04 JA |
474 | |
475 | if (queue_mode == NULL_Q_MQ) { | |
cdef54dd | 476 | nullb->tag_set.ops = &null_mq_ops; |
24d2f903 CH |
477 | nullb->tag_set.nr_hw_queues = submit_queues; |
478 | nullb->tag_set.queue_depth = hw_queue_depth; | |
479 | nullb->tag_set.numa_node = home_node; | |
480 | nullb->tag_set.cmd_size = sizeof(struct nullb_cmd); | |
481 | nullb->tag_set.flags = BLK_MQ_F_SHOULD_MERGE; | |
482 | nullb->tag_set.driver_data = nullb; | |
483 | ||
484 | if (blk_mq_alloc_tag_set(&nullb->tag_set)) | |
485 | goto out_cleanup_queues; | |
486 | ||
487 | nullb->q = blk_mq_init_queue(&nullb->tag_set); | |
488 | if (!nullb->q) | |
489 | goto out_cleanup_tags; | |
f2298c04 JA |
490 | } else if (queue_mode == NULL_Q_BIO) { |
491 | nullb->q = blk_alloc_queue_node(GFP_KERNEL, home_node); | |
24d2f903 CH |
492 | if (!nullb->q) |
493 | goto out_cleanup_queues; | |
f2298c04 | 494 | blk_queue_make_request(nullb->q, null_queue_bio); |
2d263a78 | 495 | init_driver_queues(nullb); |
f2298c04 JA |
496 | } else { |
497 | nullb->q = blk_init_queue_node(null_request_fn, &nullb->lock, home_node); | |
24d2f903 CH |
498 | if (!nullb->q) |
499 | goto out_cleanup_queues; | |
f2298c04 | 500 | blk_queue_prep_rq(nullb->q, null_rq_prep_fn); |
24d2f903 | 501 | blk_queue_softirq_done(nullb->q, null_softirq_done_fn); |
2d263a78 | 502 | init_driver_queues(nullb); |
f2298c04 JA |
503 | } |
504 | ||
f2298c04 JA |
505 | nullb->q->queuedata = nullb; |
506 | queue_flag_set_unlocked(QUEUE_FLAG_NONROT, nullb->q); | |
507 | ||
508 | disk = nullb->disk = alloc_disk_node(1, home_node); | |
24d2f903 CH |
509 | if (!disk) |
510 | goto out_cleanup_blk_queue; | |
f2298c04 JA |
511 | |
512 | mutex_lock(&lock); | |
513 | list_add_tail(&nullb->list, &nullb_list); | |
514 | nullb->index = nullb_indexes++; | |
515 | mutex_unlock(&lock); | |
516 | ||
517 | blk_queue_logical_block_size(nullb->q, bs); | |
518 | blk_queue_physical_block_size(nullb->q, bs); | |
519 | ||
520 | size = gb * 1024 * 1024 * 1024ULL; | |
521 | sector_div(size, bs); | |
522 | set_capacity(disk, size); | |
523 | ||
524 | disk->flags |= GENHD_FL_EXT_DEVT; | |
525 | disk->major = null_major; | |
526 | disk->first_minor = nullb->index; | |
527 | disk->fops = &null_fops; | |
528 | disk->private_data = nullb; | |
529 | disk->queue = nullb->q; | |
530 | sprintf(disk->disk_name, "nullb%d", nullb->index); | |
531 | add_disk(disk); | |
532 | return 0; | |
24d2f903 CH |
533 | |
534 | out_cleanup_blk_queue: | |
535 | blk_cleanup_queue(nullb->q); | |
536 | out_cleanup_tags: | |
537 | if (queue_mode == NULL_Q_MQ) | |
538 | blk_mq_free_tag_set(&nullb->tag_set); | |
539 | out_cleanup_queues: | |
540 | cleanup_queues(nullb); | |
541 | out_free_nullb: | |
542 | kfree(nullb); | |
543 | out: | |
544 | return -ENOMEM; | |
f2298c04 JA |
545 | } |
546 | ||
547 | static int __init null_init(void) | |
548 | { | |
549 | unsigned int i; | |
550 | ||
9967d8ac R |
551 | if (bs > PAGE_SIZE) { |
552 | pr_warn("null_blk: invalid block size\n"); | |
553 | pr_warn("null_blk: defaults block size to %lu\n", PAGE_SIZE); | |
554 | bs = PAGE_SIZE; | |
555 | } | |
f2298c04 | 556 | |
d15ee6b1 | 557 | if (queue_mode == NULL_Q_MQ && use_per_node_hctx) { |
fc1bc354 | 558 | if (submit_queues < nr_online_nodes) { |
d15ee6b1 MB |
559 | pr_warn("null_blk: submit_queues param is set to %u.", |
560 | nr_online_nodes); | |
fc1bc354 MB |
561 | submit_queues = nr_online_nodes; |
562 | } | |
d15ee6b1 | 563 | } else if (submit_queues > nr_cpu_ids) |
f2298c04 JA |
564 | submit_queues = nr_cpu_ids; |
565 | else if (!submit_queues) | |
566 | submit_queues = 1; | |
567 | ||
568 | mutex_init(&lock); | |
569 | ||
570 | /* Initialize a separate list for each CPU for issuing softirqs */ | |
571 | for_each_possible_cpu(i) { | |
572 | struct completion_queue *cq = &per_cpu(completion_queues, i); | |
573 | ||
574 | init_llist_head(&cq->list); | |
575 | ||
576 | if (irqmode != NULL_IRQ_TIMER) | |
577 | continue; | |
578 | ||
579 | hrtimer_init(&cq->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); | |
580 | cq->timer.function = null_cmd_timer_expired; | |
581 | } | |
582 | ||
583 | null_major = register_blkdev(0, "nullb"); | |
584 | if (null_major < 0) | |
585 | return null_major; | |
586 | ||
587 | for (i = 0; i < nr_devices; i++) { | |
588 | if (null_add_dev()) { | |
589 | unregister_blkdev(null_major, "nullb"); | |
590 | return -EINVAL; | |
591 | } | |
592 | } | |
593 | ||
594 | pr_info("null: module loaded\n"); | |
595 | return 0; | |
596 | } | |
597 | ||
598 | static void __exit null_exit(void) | |
599 | { | |
600 | struct nullb *nullb; | |
601 | ||
602 | unregister_blkdev(null_major, "nullb"); | |
603 | ||
604 | mutex_lock(&lock); | |
605 | while (!list_empty(&nullb_list)) { | |
606 | nullb = list_entry(nullb_list.next, struct nullb, list); | |
607 | null_del_dev(nullb); | |
608 | } | |
609 | mutex_unlock(&lock); | |
610 | } | |
611 | ||
612 | module_init(null_init); | |
613 | module_exit(null_exit); | |
614 | ||
615 | MODULE_AUTHOR("Jens Axboe <jaxboe@fusionio.com>"); | |
616 | MODULE_LICENSE("GPL"); |