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f2298c04 JA |
1 | #include <linux/module.h> |
2 | #include <linux/moduleparam.h> | |
3 | #include <linux/sched.h> | |
4 | #include <linux/fs.h> | |
5 | #include <linux/blkdev.h> | |
6 | #include <linux/init.h> | |
7 | #include <linux/slab.h> | |
8 | #include <linux/blk-mq.h> | |
9 | #include <linux/hrtimer.h> | |
10 | ||
11 | struct nullb_cmd { | |
12 | struct list_head list; | |
13 | struct llist_node ll_list; | |
14 | struct call_single_data csd; | |
15 | struct request *rq; | |
16 | struct bio *bio; | |
17 | unsigned int tag; | |
18 | struct nullb_queue *nq; | |
19 | }; | |
20 | ||
21 | struct nullb_queue { | |
22 | unsigned long *tag_map; | |
23 | wait_queue_head_t wait; | |
24 | unsigned int queue_depth; | |
25 | ||
26 | struct nullb_cmd *cmds; | |
27 | }; | |
28 | ||
29 | struct nullb { | |
30 | struct list_head list; | |
31 | unsigned int index; | |
32 | struct request_queue *q; | |
33 | struct gendisk *disk; | |
34 | struct hrtimer timer; | |
35 | unsigned int queue_depth; | |
36 | spinlock_t lock; | |
37 | ||
38 | struct nullb_queue *queues; | |
39 | unsigned int nr_queues; | |
40 | }; | |
41 | ||
42 | static LIST_HEAD(nullb_list); | |
43 | static struct mutex lock; | |
44 | static int null_major; | |
45 | static int nullb_indexes; | |
46 | ||
47 | struct completion_queue { | |
48 | struct llist_head list; | |
49 | struct hrtimer timer; | |
50 | }; | |
51 | ||
52 | /* | |
53 | * These are per-cpu for now, they will need to be configured by the | |
54 | * complete_queues parameter and appropriately mapped. | |
55 | */ | |
56 | static DEFINE_PER_CPU(struct completion_queue, completion_queues); | |
57 | ||
58 | enum { | |
59 | NULL_IRQ_NONE = 0, | |
60 | NULL_IRQ_SOFTIRQ = 1, | |
61 | NULL_IRQ_TIMER = 2, | |
62 | ||
63 | NULL_Q_BIO = 0, | |
64 | NULL_Q_RQ = 1, | |
65 | NULL_Q_MQ = 2, | |
66 | }; | |
67 | ||
2d263a78 | 68 | static int submit_queues; |
f2298c04 JA |
69 | module_param(submit_queues, int, S_IRUGO); |
70 | MODULE_PARM_DESC(submit_queues, "Number of submission queues"); | |
71 | ||
72 | static int home_node = NUMA_NO_NODE; | |
73 | module_param(home_node, int, S_IRUGO); | |
74 | MODULE_PARM_DESC(home_node, "Home node for the device"); | |
75 | ||
76 | static int queue_mode = NULL_Q_MQ; | |
77 | module_param(queue_mode, int, S_IRUGO); | |
78 | MODULE_PARM_DESC(use_mq, "Use blk-mq interface (0=bio,1=rq,2=multiqueue)"); | |
79 | ||
80 | static int gb = 250; | |
81 | module_param(gb, int, S_IRUGO); | |
82 | MODULE_PARM_DESC(gb, "Size in GB"); | |
83 | ||
84 | static int bs = 512; | |
85 | module_param(bs, int, S_IRUGO); | |
86 | MODULE_PARM_DESC(bs, "Block size (in bytes)"); | |
87 | ||
88 | static int nr_devices = 2; | |
89 | module_param(nr_devices, int, S_IRUGO); | |
90 | MODULE_PARM_DESC(nr_devices, "Number of devices to register"); | |
91 | ||
92 | static int irqmode = NULL_IRQ_SOFTIRQ; | |
93 | module_param(irqmode, int, S_IRUGO); | |
94 | MODULE_PARM_DESC(irqmode, "IRQ completion handler. 0-none, 1-softirq, 2-timer"); | |
95 | ||
96 | static int completion_nsec = 10000; | |
97 | module_param(completion_nsec, int, S_IRUGO); | |
98 | MODULE_PARM_DESC(completion_nsec, "Time in ns to complete a request in hardware. Default: 10,000ns"); | |
99 | ||
100 | static int hw_queue_depth = 64; | |
101 | module_param(hw_queue_depth, int, S_IRUGO); | |
102 | MODULE_PARM_DESC(hw_queue_depth, "Queue depth for each hardware queue. Default: 64"); | |
103 | ||
104 | static bool use_per_node_hctx = true; | |
105 | module_param(use_per_node_hctx, bool, S_IRUGO); | |
106 | MODULE_PARM_DESC(use_per_node_hctx, "Use per-node allocation for hardware context queues. Default: true"); | |
107 | ||
108 | static void put_tag(struct nullb_queue *nq, unsigned int tag) | |
109 | { | |
110 | clear_bit_unlock(tag, nq->tag_map); | |
111 | ||
112 | if (waitqueue_active(&nq->wait)) | |
113 | wake_up(&nq->wait); | |
114 | } | |
115 | ||
116 | static unsigned int get_tag(struct nullb_queue *nq) | |
117 | { | |
118 | unsigned int tag; | |
119 | ||
120 | do { | |
121 | tag = find_first_zero_bit(nq->tag_map, nq->queue_depth); | |
122 | if (tag >= nq->queue_depth) | |
123 | return -1U; | |
124 | } while (test_and_set_bit_lock(tag, nq->tag_map)); | |
125 | ||
126 | return tag; | |
127 | } | |
128 | ||
129 | static void free_cmd(struct nullb_cmd *cmd) | |
130 | { | |
131 | put_tag(cmd->nq, cmd->tag); | |
132 | } | |
133 | ||
134 | static struct nullb_cmd *__alloc_cmd(struct nullb_queue *nq) | |
135 | { | |
136 | struct nullb_cmd *cmd; | |
137 | unsigned int tag; | |
138 | ||
139 | tag = get_tag(nq); | |
140 | if (tag != -1U) { | |
141 | cmd = &nq->cmds[tag]; | |
142 | cmd->tag = tag; | |
143 | cmd->nq = nq; | |
144 | return cmd; | |
145 | } | |
146 | ||
147 | return NULL; | |
148 | } | |
149 | ||
150 | static struct nullb_cmd *alloc_cmd(struct nullb_queue *nq, int can_wait) | |
151 | { | |
152 | struct nullb_cmd *cmd; | |
153 | DEFINE_WAIT(wait); | |
154 | ||
155 | cmd = __alloc_cmd(nq); | |
156 | if (cmd || !can_wait) | |
157 | return cmd; | |
158 | ||
159 | do { | |
160 | prepare_to_wait(&nq->wait, &wait, TASK_UNINTERRUPTIBLE); | |
161 | cmd = __alloc_cmd(nq); | |
162 | if (cmd) | |
163 | break; | |
164 | ||
165 | io_schedule(); | |
166 | } while (1); | |
167 | ||
168 | finish_wait(&nq->wait, &wait); | |
169 | return cmd; | |
170 | } | |
171 | ||
172 | static void end_cmd(struct nullb_cmd *cmd) | |
173 | { | |
174 | if (cmd->rq) { | |
175 | if (queue_mode == NULL_Q_MQ) | |
176 | blk_mq_end_io(cmd->rq, 0); | |
177 | else { | |
178 | INIT_LIST_HEAD(&cmd->rq->queuelist); | |
179 | blk_end_request_all(cmd->rq, 0); | |
180 | } | |
181 | } else if (cmd->bio) | |
182 | bio_endio(cmd->bio, 0); | |
183 | ||
184 | if (queue_mode != NULL_Q_MQ) | |
185 | free_cmd(cmd); | |
186 | } | |
187 | ||
188 | static enum hrtimer_restart null_cmd_timer_expired(struct hrtimer *timer) | |
189 | { | |
190 | struct completion_queue *cq; | |
191 | struct llist_node *entry; | |
192 | struct nullb_cmd *cmd; | |
193 | ||
194 | cq = &per_cpu(completion_queues, smp_processor_id()); | |
195 | ||
196 | while ((entry = llist_del_all(&cq->list)) != NULL) { | |
197 | do { | |
198 | cmd = container_of(entry, struct nullb_cmd, ll_list); | |
199 | end_cmd(cmd); | |
200 | entry = entry->next; | |
201 | } while (entry); | |
202 | } | |
203 | ||
204 | return HRTIMER_NORESTART; | |
205 | } | |
206 | ||
207 | static void null_cmd_end_timer(struct nullb_cmd *cmd) | |
208 | { | |
209 | struct completion_queue *cq = &per_cpu(completion_queues, get_cpu()); | |
210 | ||
211 | cmd->ll_list.next = NULL; | |
212 | if (llist_add(&cmd->ll_list, &cq->list)) { | |
213 | ktime_t kt = ktime_set(0, completion_nsec); | |
214 | ||
215 | hrtimer_start(&cq->timer, kt, HRTIMER_MODE_REL); | |
216 | } | |
217 | ||
218 | put_cpu(); | |
219 | } | |
220 | ||
221 | static void null_softirq_done_fn(struct request *rq) | |
222 | { | |
223 | blk_end_request_all(rq, 0); | |
224 | } | |
225 | ||
044c8d4b | 226 | #ifdef CONFIG_SMP |
f2298c04 JA |
227 | |
228 | static void null_ipi_cmd_end_io(void *data) | |
229 | { | |
230 | struct completion_queue *cq; | |
231 | struct llist_node *entry, *next; | |
232 | struct nullb_cmd *cmd; | |
233 | ||
234 | cq = &per_cpu(completion_queues, smp_processor_id()); | |
235 | ||
236 | entry = llist_del_all(&cq->list); | |
237 | ||
238 | while (entry) { | |
239 | next = entry->next; | |
240 | cmd = llist_entry(entry, struct nullb_cmd, ll_list); | |
241 | end_cmd(cmd); | |
242 | entry = next; | |
243 | } | |
244 | } | |
245 | ||
246 | static void null_cmd_end_ipi(struct nullb_cmd *cmd) | |
247 | { | |
248 | struct call_single_data *data = &cmd->csd; | |
249 | int cpu = get_cpu(); | |
250 | struct completion_queue *cq = &per_cpu(completion_queues, cpu); | |
251 | ||
252 | cmd->ll_list.next = NULL; | |
253 | ||
254 | if (llist_add(&cmd->ll_list, &cq->list)) { | |
255 | data->func = null_ipi_cmd_end_io; | |
256 | data->flags = 0; | |
257 | __smp_call_function_single(cpu, data, 0); | |
258 | } | |
259 | ||
260 | put_cpu(); | |
261 | } | |
262 | ||
044c8d4b | 263 | #endif /* CONFIG_SMP */ |
f2298c04 JA |
264 | |
265 | static inline void null_handle_cmd(struct nullb_cmd *cmd) | |
266 | { | |
267 | /* Complete IO by inline, softirq or timer */ | |
268 | switch (irqmode) { | |
269 | case NULL_IRQ_NONE: | |
270 | end_cmd(cmd); | |
271 | break; | |
272 | case NULL_IRQ_SOFTIRQ: | |
044c8d4b | 273 | #ifdef CONFIG_SMP |
f2298c04 JA |
274 | null_cmd_end_ipi(cmd); |
275 | #else | |
276 | end_cmd(cmd); | |
277 | #endif | |
278 | break; | |
279 | case NULL_IRQ_TIMER: | |
280 | null_cmd_end_timer(cmd); | |
281 | break; | |
282 | } | |
283 | } | |
284 | ||
285 | static struct nullb_queue *nullb_to_queue(struct nullb *nullb) | |
286 | { | |
287 | int index = 0; | |
288 | ||
289 | if (nullb->nr_queues != 1) | |
290 | index = raw_smp_processor_id() / ((nr_cpu_ids + nullb->nr_queues - 1) / nullb->nr_queues); | |
291 | ||
292 | return &nullb->queues[index]; | |
293 | } | |
294 | ||
295 | static void null_queue_bio(struct request_queue *q, struct bio *bio) | |
296 | { | |
297 | struct nullb *nullb = q->queuedata; | |
298 | struct nullb_queue *nq = nullb_to_queue(nullb); | |
299 | struct nullb_cmd *cmd; | |
300 | ||
301 | cmd = alloc_cmd(nq, 1); | |
302 | cmd->bio = bio; | |
303 | ||
304 | null_handle_cmd(cmd); | |
305 | } | |
306 | ||
307 | static int null_rq_prep_fn(struct request_queue *q, struct request *req) | |
308 | { | |
309 | struct nullb *nullb = q->queuedata; | |
310 | struct nullb_queue *nq = nullb_to_queue(nullb); | |
311 | struct nullb_cmd *cmd; | |
312 | ||
313 | cmd = alloc_cmd(nq, 0); | |
314 | if (cmd) { | |
315 | cmd->rq = req; | |
316 | req->special = cmd; | |
317 | return BLKPREP_OK; | |
318 | } | |
319 | ||
320 | return BLKPREP_DEFER; | |
321 | } | |
322 | ||
323 | static void null_request_fn(struct request_queue *q) | |
324 | { | |
325 | struct request *rq; | |
326 | ||
327 | while ((rq = blk_fetch_request(q)) != NULL) { | |
328 | struct nullb_cmd *cmd = rq->special; | |
329 | ||
330 | spin_unlock_irq(q->queue_lock); | |
331 | null_handle_cmd(cmd); | |
332 | spin_lock_irq(q->queue_lock); | |
333 | } | |
334 | } | |
335 | ||
336 | static int null_queue_rq(struct blk_mq_hw_ctx *hctx, struct request *rq) | |
337 | { | |
338 | struct nullb_cmd *cmd = rq->special; | |
339 | ||
340 | cmd->rq = rq; | |
341 | cmd->nq = hctx->driver_data; | |
342 | ||
343 | null_handle_cmd(cmd); | |
344 | return BLK_MQ_RQ_QUEUE_OK; | |
345 | } | |
346 | ||
347 | static struct blk_mq_hw_ctx *null_alloc_hctx(struct blk_mq_reg *reg, unsigned int hctx_index) | |
348 | { | |
349 | return kzalloc_node(sizeof(struct blk_mq_hw_ctx), GFP_KERNEL, | |
350 | hctx_index); | |
351 | } | |
352 | ||
353 | static void null_free_hctx(struct blk_mq_hw_ctx *hctx, unsigned int hctx_index) | |
354 | { | |
355 | kfree(hctx); | |
356 | } | |
357 | ||
2d263a78 MB |
358 | static void null_init_queue(struct nullb *nullb, struct nullb_queue *nq) |
359 | { | |
360 | BUG_ON(!nullb); | |
361 | BUG_ON(!nq); | |
362 | ||
363 | init_waitqueue_head(&nq->wait); | |
364 | nq->queue_depth = nullb->queue_depth; | |
365 | } | |
366 | ||
f2298c04 JA |
367 | static int null_init_hctx(struct blk_mq_hw_ctx *hctx, void *data, |
368 | unsigned int index) | |
369 | { | |
370 | struct nullb *nullb = data; | |
371 | struct nullb_queue *nq = &nullb->queues[index]; | |
372 | ||
f2298c04 | 373 | hctx->driver_data = nq; |
2d263a78 MB |
374 | null_init_queue(nullb, nq); |
375 | nullb->nr_queues++; | |
f2298c04 JA |
376 | |
377 | return 0; | |
378 | } | |
379 | ||
380 | static struct blk_mq_ops null_mq_ops = { | |
381 | .queue_rq = null_queue_rq, | |
382 | .map_queue = blk_mq_map_queue, | |
383 | .init_hctx = null_init_hctx, | |
384 | }; | |
385 | ||
386 | static struct blk_mq_reg null_mq_reg = { | |
387 | .ops = &null_mq_ops, | |
388 | .queue_depth = 64, | |
389 | .cmd_size = sizeof(struct nullb_cmd), | |
390 | .flags = BLK_MQ_F_SHOULD_MERGE, | |
391 | }; | |
392 | ||
393 | static void null_del_dev(struct nullb *nullb) | |
394 | { | |
395 | list_del_init(&nullb->list); | |
396 | ||
397 | del_gendisk(nullb->disk); | |
398 | if (queue_mode == NULL_Q_MQ) | |
399 | blk_mq_free_queue(nullb->q); | |
400 | else | |
401 | blk_cleanup_queue(nullb->q); | |
402 | put_disk(nullb->disk); | |
403 | kfree(nullb); | |
404 | } | |
405 | ||
406 | static int null_open(struct block_device *bdev, fmode_t mode) | |
407 | { | |
408 | return 0; | |
409 | } | |
410 | ||
411 | static void null_release(struct gendisk *disk, fmode_t mode) | |
412 | { | |
413 | } | |
414 | ||
415 | static const struct block_device_operations null_fops = { | |
416 | .owner = THIS_MODULE, | |
417 | .open = null_open, | |
418 | .release = null_release, | |
419 | }; | |
420 | ||
421 | static int setup_commands(struct nullb_queue *nq) | |
422 | { | |
423 | struct nullb_cmd *cmd; | |
424 | int i, tag_size; | |
425 | ||
426 | nq->cmds = kzalloc(nq->queue_depth * sizeof(*cmd), GFP_KERNEL); | |
427 | if (!nq->cmds) | |
2d263a78 | 428 | return -ENOMEM; |
f2298c04 JA |
429 | |
430 | tag_size = ALIGN(nq->queue_depth, BITS_PER_LONG) / BITS_PER_LONG; | |
431 | nq->tag_map = kzalloc(tag_size * sizeof(unsigned long), GFP_KERNEL); | |
432 | if (!nq->tag_map) { | |
433 | kfree(nq->cmds); | |
2d263a78 | 434 | return -ENOMEM; |
f2298c04 JA |
435 | } |
436 | ||
437 | for (i = 0; i < nq->queue_depth; i++) { | |
438 | cmd = &nq->cmds[i]; | |
439 | INIT_LIST_HEAD(&cmd->list); | |
440 | cmd->ll_list.next = NULL; | |
441 | cmd->tag = -1U; | |
442 | } | |
443 | ||
444 | return 0; | |
445 | } | |
446 | ||
447 | static void cleanup_queue(struct nullb_queue *nq) | |
448 | { | |
449 | kfree(nq->tag_map); | |
450 | kfree(nq->cmds); | |
451 | } | |
452 | ||
453 | static void cleanup_queues(struct nullb *nullb) | |
454 | { | |
455 | int i; | |
456 | ||
457 | for (i = 0; i < nullb->nr_queues; i++) | |
458 | cleanup_queue(&nullb->queues[i]); | |
459 | ||
460 | kfree(nullb->queues); | |
461 | } | |
462 | ||
463 | static int setup_queues(struct nullb *nullb) | |
464 | { | |
2d263a78 MB |
465 | nullb->queues = kzalloc(submit_queues * sizeof(struct nullb_queue), |
466 | GFP_KERNEL); | |
f2298c04 | 467 | if (!nullb->queues) |
2d263a78 | 468 | return -ENOMEM; |
f2298c04 JA |
469 | |
470 | nullb->nr_queues = 0; | |
471 | nullb->queue_depth = hw_queue_depth; | |
472 | ||
2d263a78 MB |
473 | return 0; |
474 | } | |
475 | ||
476 | static int init_driver_queues(struct nullb *nullb) | |
477 | { | |
478 | struct nullb_queue *nq; | |
479 | int i, ret = 0; | |
f2298c04 JA |
480 | |
481 | for (i = 0; i < submit_queues; i++) { | |
482 | nq = &nullb->queues[i]; | |
2d263a78 MB |
483 | |
484 | null_init_queue(nullb, nq); | |
485 | ||
486 | ret = setup_commands(nq); | |
487 | if (ret) | |
488 | goto err_queue; | |
f2298c04 JA |
489 | nullb->nr_queues++; |
490 | } | |
491 | ||
2d263a78 MB |
492 | return 0; |
493 | err_queue: | |
f2298c04 | 494 | cleanup_queues(nullb); |
2d263a78 | 495 | return ret; |
f2298c04 JA |
496 | } |
497 | ||
498 | static int null_add_dev(void) | |
499 | { | |
500 | struct gendisk *disk; | |
501 | struct nullb *nullb; | |
502 | sector_t size; | |
503 | ||
504 | nullb = kzalloc_node(sizeof(*nullb), GFP_KERNEL, home_node); | |
505 | if (!nullb) | |
506 | return -ENOMEM; | |
507 | ||
508 | spin_lock_init(&nullb->lock); | |
509 | ||
510 | if (setup_queues(nullb)) | |
511 | goto err; | |
512 | ||
513 | if (queue_mode == NULL_Q_MQ) { | |
514 | null_mq_reg.numa_node = home_node; | |
515 | null_mq_reg.queue_depth = hw_queue_depth; | |
0c56010c | 516 | null_mq_reg.nr_hw_queues = submit_queues; |
f2298c04 JA |
517 | |
518 | if (use_per_node_hctx) { | |
519 | null_mq_reg.ops->alloc_hctx = null_alloc_hctx; | |
520 | null_mq_reg.ops->free_hctx = null_free_hctx; | |
f2298c04 JA |
521 | } else { |
522 | null_mq_reg.ops->alloc_hctx = blk_mq_alloc_single_hw_queue; | |
523 | null_mq_reg.ops->free_hctx = blk_mq_free_single_hw_queue; | |
f2298c04 JA |
524 | } |
525 | ||
526 | nullb->q = blk_mq_init_queue(&null_mq_reg, nullb); | |
527 | } else if (queue_mode == NULL_Q_BIO) { | |
528 | nullb->q = blk_alloc_queue_node(GFP_KERNEL, home_node); | |
529 | blk_queue_make_request(nullb->q, null_queue_bio); | |
2d263a78 | 530 | init_driver_queues(nullb); |
f2298c04 JA |
531 | } else { |
532 | nullb->q = blk_init_queue_node(null_request_fn, &nullb->lock, home_node); | |
533 | blk_queue_prep_rq(nullb->q, null_rq_prep_fn); | |
534 | if (nullb->q) | |
535 | blk_queue_softirq_done(nullb->q, null_softirq_done_fn); | |
2d263a78 | 536 | init_driver_queues(nullb); |
f2298c04 JA |
537 | } |
538 | ||
539 | if (!nullb->q) | |
540 | goto queue_fail; | |
541 | ||
542 | nullb->q->queuedata = nullb; | |
543 | queue_flag_set_unlocked(QUEUE_FLAG_NONROT, nullb->q); | |
544 | ||
545 | disk = nullb->disk = alloc_disk_node(1, home_node); | |
546 | if (!disk) { | |
547 | queue_fail: | |
548 | if (queue_mode == NULL_Q_MQ) | |
549 | blk_mq_free_queue(nullb->q); | |
550 | else | |
551 | blk_cleanup_queue(nullb->q); | |
552 | cleanup_queues(nullb); | |
553 | err: | |
554 | kfree(nullb); | |
555 | return -ENOMEM; | |
556 | } | |
557 | ||
558 | mutex_lock(&lock); | |
559 | list_add_tail(&nullb->list, &nullb_list); | |
560 | nullb->index = nullb_indexes++; | |
561 | mutex_unlock(&lock); | |
562 | ||
563 | blk_queue_logical_block_size(nullb->q, bs); | |
564 | blk_queue_physical_block_size(nullb->q, bs); | |
565 | ||
566 | size = gb * 1024 * 1024 * 1024ULL; | |
567 | sector_div(size, bs); | |
568 | set_capacity(disk, size); | |
569 | ||
570 | disk->flags |= GENHD_FL_EXT_DEVT; | |
571 | disk->major = null_major; | |
572 | disk->first_minor = nullb->index; | |
573 | disk->fops = &null_fops; | |
574 | disk->private_data = nullb; | |
575 | disk->queue = nullb->q; | |
576 | sprintf(disk->disk_name, "nullb%d", nullb->index); | |
577 | add_disk(disk); | |
578 | return 0; | |
579 | } | |
580 | ||
581 | static int __init null_init(void) | |
582 | { | |
583 | unsigned int i; | |
584 | ||
044c8d4b | 585 | #if !defined(CONFIG_SMP) |
f2298c04 JA |
586 | if (irqmode == NULL_IRQ_SOFTIRQ) { |
587 | pr_warn("null_blk: softirq completions not available.\n"); | |
588 | pr_warn("null_blk: using direct completions.\n"); | |
589 | irqmode = NULL_IRQ_NONE; | |
590 | } | |
591 | #endif | |
592 | ||
2d263a78 MB |
593 | if (queue_mode == NULL_Q_MQ && use_per_node_hctx) |
594 | submit_queues = nr_online_nodes; | |
595 | else if (submit_queues > nr_cpu_ids) | |
f2298c04 JA |
596 | submit_queues = nr_cpu_ids; |
597 | else if (!submit_queues) | |
598 | submit_queues = 1; | |
599 | ||
600 | mutex_init(&lock); | |
601 | ||
602 | /* Initialize a separate list for each CPU for issuing softirqs */ | |
603 | for_each_possible_cpu(i) { | |
604 | struct completion_queue *cq = &per_cpu(completion_queues, i); | |
605 | ||
606 | init_llist_head(&cq->list); | |
607 | ||
608 | if (irqmode != NULL_IRQ_TIMER) | |
609 | continue; | |
610 | ||
611 | hrtimer_init(&cq->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); | |
612 | cq->timer.function = null_cmd_timer_expired; | |
613 | } | |
614 | ||
615 | null_major = register_blkdev(0, "nullb"); | |
616 | if (null_major < 0) | |
617 | return null_major; | |
618 | ||
619 | for (i = 0; i < nr_devices; i++) { | |
620 | if (null_add_dev()) { | |
621 | unregister_blkdev(null_major, "nullb"); | |
622 | return -EINVAL; | |
623 | } | |
624 | } | |
625 | ||
626 | pr_info("null: module loaded\n"); | |
627 | return 0; | |
628 | } | |
629 | ||
630 | static void __exit null_exit(void) | |
631 | { | |
632 | struct nullb *nullb; | |
633 | ||
634 | unregister_blkdev(null_major, "nullb"); | |
635 | ||
636 | mutex_lock(&lock); | |
637 | while (!list_empty(&nullb_list)) { | |
638 | nullb = list_entry(nullb_list.next, struct nullb, list); | |
639 | null_del_dev(nullb); | |
640 | } | |
641 | mutex_unlock(&lock); | |
642 | } | |
643 | ||
644 | module_init(null_init); | |
645 | module_exit(null_exit); | |
646 | ||
647 | MODULE_AUTHOR("Jens Axboe <jaxboe@fusionio.com>"); | |
648 | MODULE_LICENSE("GPL"); |