1#include <linux/module.h>
2
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#include <linux/lightnvm.h>
12
13struct nullb_cmd {
14 struct list_head list;
15 struct llist_node ll_list;
16 struct call_single_data csd;
17 struct request *rq;
18 struct bio *bio;
19 unsigned int tag;
20 struct nullb_queue *nq;
21 struct hrtimer timer;
22};
23
24struct nullb_queue {
25 unsigned long *tag_map;
26 wait_queue_head_t wait;
27 unsigned int queue_depth;
28
29 struct nullb_cmd *cmds;
30};
31
32struct nullb {
33 struct list_head list;
34 unsigned int index;
35 struct request_queue *q;
36 struct gendisk *disk;
37 struct nvm_dev *ndev;
38 struct blk_mq_tag_set *tag_set;
39 struct blk_mq_tag_set __tag_set;
40 struct hrtimer timer;
41 unsigned int queue_depth;
42 spinlock_t lock;
43
44 struct nullb_queue *queues;
45 unsigned int nr_queues;
46 char disk_name[DISK_NAME_LEN];
47};
48
49static LIST_HEAD(nullb_list);
50static struct mutex lock;
51static int null_major;
52static int nullb_indexes;
53static struct kmem_cache *ppa_cache;
54static struct blk_mq_tag_set tag_set;
55
56enum {
57 NULL_IRQ_NONE = 0,
58 NULL_IRQ_SOFTIRQ = 1,
59 NULL_IRQ_TIMER = 2,
60};
61
62enum {
63 NULL_Q_BIO = 0,
64 NULL_Q_RQ = 1,
65 NULL_Q_MQ = 2,
66};
67
68static int submit_queues;
69module_param(submit_queues, int, S_IRUGO);
70MODULE_PARM_DESC(submit_queues, "Number of submission queues");
71
72static int home_node = NUMA_NO_NODE;
73module_param(home_node, int, S_IRUGO);
74MODULE_PARM_DESC(home_node, "Home node for the device");
75
76static int queue_mode = NULL_Q_MQ;
77
78static int null_param_store_val(const char *str, int *val, int min, int max)
79{
80 int ret, new_val;
81
82 ret = kstrtoint(str, 10, &new_val);
83 if (ret)
84 return -EINVAL;
85
86 if (new_val < min || new_val > max)
87 return -EINVAL;
88
89 *val = new_val;
90 return 0;
91}
92
93static int null_set_queue_mode(const char *str, const struct kernel_param *kp)
94{
95 return null_param_store_val(str, &queue_mode, NULL_Q_BIO, NULL_Q_MQ);
96}
97
98static const struct kernel_param_ops null_queue_mode_param_ops = {
99 .set = null_set_queue_mode,
100 .get = param_get_int,
101};
102
103device_param_cb(queue_mode, &null_queue_mode_param_ops, &queue_mode, S_IRUGO);
104MODULE_PARM_DESC(queue_mode, "Block interface to use (0=bio,1=rq,2=multiqueue)");
105
106static int gb = 250;
107module_param(gb, int, S_IRUGO);
108MODULE_PARM_DESC(gb, "Size in GB");
109
110static int bs = 512;
111module_param(bs, int, S_IRUGO);
112MODULE_PARM_DESC(bs, "Block size (in bytes)");
113
114static int nr_devices = 1;
115module_param(nr_devices, int, S_IRUGO);
116MODULE_PARM_DESC(nr_devices, "Number of devices to register");
117
118static bool use_lightnvm;
119module_param(use_lightnvm, bool, S_IRUGO);
120MODULE_PARM_DESC(use_lightnvm, "Register as a LightNVM device");
121
122static bool blocking;
123module_param(blocking, bool, S_IRUGO);
124MODULE_PARM_DESC(blocking, "Register as a blocking blk-mq driver device");
125
126static bool shared_tags;
127module_param(shared_tags, bool, S_IRUGO);
128MODULE_PARM_DESC(shared_tags, "Share tag set between devices for blk-mq");
129
130static int irqmode = NULL_IRQ_SOFTIRQ;
131
132static int null_set_irqmode(const char *str, const struct kernel_param *kp)
133{
134 return null_param_store_val(str, &irqmode, NULL_IRQ_NONE,
135 NULL_IRQ_TIMER);
136}
137
138static const struct kernel_param_ops null_irqmode_param_ops = {
139 .set = null_set_irqmode,
140 .get = param_get_int,
141};
142
143device_param_cb(irqmode, &null_irqmode_param_ops, &irqmode, S_IRUGO);
144MODULE_PARM_DESC(irqmode, "IRQ completion handler. 0-none, 1-softirq, 2-timer");
145
146static unsigned long completion_nsec = 10000;
147module_param(completion_nsec, ulong, S_IRUGO);
148MODULE_PARM_DESC(completion_nsec, "Time in ns to complete a request in hardware. Default: 10,000ns");
149
150static int hw_queue_depth = 64;
151module_param(hw_queue_depth, int, S_IRUGO);
152MODULE_PARM_DESC(hw_queue_depth, "Queue depth for each hardware queue. Default: 64");
153
154static bool use_per_node_hctx = false;
155module_param(use_per_node_hctx, bool, S_IRUGO);
156MODULE_PARM_DESC(use_per_node_hctx, "Use per-node allocation for hardware context queues. Default: false");
157
158static void put_tag(struct nullb_queue *nq, unsigned int tag)
159{
160 clear_bit_unlock(tag, nq->tag_map);
161
162 if (waitqueue_active(&nq->wait))
163 wake_up(&nq->wait);
164}
165
166static unsigned int get_tag(struct nullb_queue *nq)
167{
168 unsigned int tag;
169
170 do {
171 tag = find_first_zero_bit(nq->tag_map, nq->queue_depth);
172 if (tag >= nq->queue_depth)
173 return -1U;
174 } while (test_and_set_bit_lock(tag, nq->tag_map));
175
176 return tag;
177}
178
179static void free_cmd(struct nullb_cmd *cmd)
180{
181 put_tag(cmd->nq, cmd->tag);
182}
183
184static enum hrtimer_restart null_cmd_timer_expired(struct hrtimer *timer);
185
186static struct nullb_cmd *__alloc_cmd(struct nullb_queue *nq)
187{
188 struct nullb_cmd *cmd;
189 unsigned int tag;
190
191 tag = get_tag(nq);
192 if (tag != -1U) {
193 cmd = &nq->cmds[tag];
194 cmd->tag = tag;
195 cmd->nq = nq;
196 if (irqmode == NULL_IRQ_TIMER) {
197 hrtimer_init(&cmd->timer, CLOCK_MONOTONIC,
198 HRTIMER_MODE_REL);
199 cmd->timer.function = null_cmd_timer_expired;
200 }
201 return cmd;
202 }
203
204 return NULL;
205}
206
207static struct nullb_cmd *alloc_cmd(struct nullb_queue *nq, int can_wait)
208{
209 struct nullb_cmd *cmd;
210 DEFINE_WAIT(wait);
211
212 cmd = __alloc_cmd(nq);
213 if (cmd || !can_wait)
214 return cmd;
215
216 do {
217 prepare_to_wait(&nq->wait, &wait, TASK_UNINTERRUPTIBLE);
218 cmd = __alloc_cmd(nq);
219 if (cmd)
220 break;
221
222 io_schedule();
223 } while (1);
224
225 finish_wait(&nq->wait, &wait);
226 return cmd;
227}
228
229static void end_cmd(struct nullb_cmd *cmd)
230{
231 struct request_queue *q = NULL;
232
233 if (cmd->rq)
234 q = cmd->rq->q;
235
236 switch (queue_mode) {
237 case NULL_Q_MQ:
238 blk_mq_end_request(cmd->rq, BLK_STS_OK);
239 return;
240 case NULL_Q_RQ:
241 INIT_LIST_HEAD(&cmd->rq->queuelist);
242 blk_end_request_all(cmd->rq, BLK_STS_OK);
243 break;
244 case NULL_Q_BIO:
245 bio_endio(cmd->bio);
246 break;
247 }
248
249 free_cmd(cmd);
250
251
252 if (queue_mode == NULL_Q_RQ && blk_queue_stopped(q)) {
253 unsigned long flags;
254
255 spin_lock_irqsave(q->queue_lock, flags);
256 blk_start_queue_async(q);
257 spin_unlock_irqrestore(q->queue_lock, flags);
258 }
259}
260
261static enum hrtimer_restart null_cmd_timer_expired(struct hrtimer *timer)
262{
263 end_cmd(container_of(timer, struct nullb_cmd, timer));
264
265 return HRTIMER_NORESTART;
266}
267
268static void null_cmd_end_timer(struct nullb_cmd *cmd)
269{
270 ktime_t kt = completion_nsec;
271
272 hrtimer_start(&cmd->timer, kt, HRTIMER_MODE_REL);
273}
274
275static void null_softirq_done_fn(struct request *rq)
276{
277 if (queue_mode == NULL_Q_MQ)
278 end_cmd(blk_mq_rq_to_pdu(rq));
279 else
280 end_cmd(rq->special);
281}
282
283static inline void null_handle_cmd(struct nullb_cmd *cmd)
284{
285
286 switch (irqmode) {
287 case NULL_IRQ_SOFTIRQ:
288 switch (queue_mode) {
289 case NULL_Q_MQ:
290 blk_mq_complete_request(cmd->rq);
291 break;
292 case NULL_Q_RQ:
293 blk_complete_request(cmd->rq);
294 break;
295 case NULL_Q_BIO:
296
297
298
299 end_cmd(cmd);
300 break;
301 }
302 break;
303 case NULL_IRQ_NONE:
304 end_cmd(cmd);
305 break;
306 case NULL_IRQ_TIMER:
307 null_cmd_end_timer(cmd);
308 break;
309 }
310}
311
312static struct nullb_queue *nullb_to_queue(struct nullb *nullb)
313{
314 int index = 0;
315
316 if (nullb->nr_queues != 1)
317 index = raw_smp_processor_id() / ((nr_cpu_ids + nullb->nr_queues - 1) / nullb->nr_queues);
318
319 return &nullb->queues[index];
320}
321
322static blk_qc_t null_queue_bio(struct request_queue *q, struct bio *bio)
323{
324 struct nullb *nullb = q->queuedata;
325 struct nullb_queue *nq = nullb_to_queue(nullb);
326 struct nullb_cmd *cmd;
327
328 cmd = alloc_cmd(nq, 1);
329 cmd->bio = bio;
330
331 null_handle_cmd(cmd);
332 return BLK_QC_T_NONE;
333}
334
335static int null_rq_prep_fn(struct request_queue *q, struct request *req)
336{
337 struct nullb *nullb = q->queuedata;
338 struct nullb_queue *nq = nullb_to_queue(nullb);
339 struct nullb_cmd *cmd;
340
341 cmd = alloc_cmd(nq, 0);
342 if (cmd) {
343 cmd->rq = req;
344 req->special = cmd;
345 return BLKPREP_OK;
346 }
347 blk_stop_queue(q);
348
349 return BLKPREP_DEFER;
350}
351
352static void null_request_fn(struct request_queue *q)
353{
354 struct request *rq;
355
356 while ((rq = blk_fetch_request(q)) != NULL) {
357 struct nullb_cmd *cmd = rq->special;
358
359 spin_unlock_irq(q->queue_lock);
360 null_handle_cmd(cmd);
361 spin_lock_irq(q->queue_lock);
362 }
363}
364
365static blk_status_t null_queue_rq(struct blk_mq_hw_ctx *hctx,
366 const struct blk_mq_queue_data *bd)
367{
368 struct nullb_cmd *cmd = blk_mq_rq_to_pdu(bd->rq);
369
370 might_sleep_if(hctx->flags & BLK_MQ_F_BLOCKING);
371
372 if (irqmode == NULL_IRQ_TIMER) {
373 hrtimer_init(&cmd->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
374 cmd->timer.function = null_cmd_timer_expired;
375 }
376 cmd->rq = bd->rq;
377 cmd->nq = hctx->driver_data;
378
379 blk_mq_start_request(bd->rq);
380
381 null_handle_cmd(cmd);
382 return BLK_STS_OK;
383}
384
385static const struct blk_mq_ops null_mq_ops = {
386 .queue_rq = null_queue_rq,
387 .complete = null_softirq_done_fn,
388};
389
390static void cleanup_queue(struct nullb_queue *nq)
391{
392 kfree(nq->tag_map);
393 kfree(nq->cmds);
394}
395
396static void cleanup_queues(struct nullb *nullb)
397{
398 int i;
399
400 for (i = 0; i < nullb->nr_queues; i++)
401 cleanup_queue(&nullb->queues[i]);
402
403 kfree(nullb->queues);
404}
405
406#ifdef CONFIG_NVM
407
408static void null_lnvm_end_io(struct request *rq, blk_status_t status)
409{
410 struct nvm_rq *rqd = rq->end_io_data;
411
412
413 rqd->error = status ? -EIO : 0;
414 nvm_end_io(rqd);
415
416 blk_put_request(rq);
417}
418
419static int null_lnvm_submit_io(struct nvm_dev *dev, struct nvm_rq *rqd)
420{
421 struct request_queue *q = dev->q;
422 struct request *rq;
423 struct bio *bio = rqd->bio;
424
425 rq = blk_mq_alloc_request(q,
426 op_is_write(bio_op(bio)) ? REQ_OP_DRV_OUT : REQ_OP_DRV_IN, 0);
427 if (IS_ERR(rq))
428 return -ENOMEM;
429
430 blk_init_request_from_bio(rq, bio);
431
432 rq->end_io_data = rqd;
433
434 blk_execute_rq_nowait(q, NULL, rq, 0, null_lnvm_end_io);
435
436 return 0;
437}
438
439static int null_lnvm_id(struct nvm_dev *dev, struct nvm_id *id)
440{
441 sector_t size = gb * 1024 * 1024 * 1024ULL;
442 sector_t blksize;
443 struct nvm_id_group *grp;
444
445 id->ver_id = 0x1;
446 id->vmnt = 0;
447 id->cap = 0x2;
448 id->dom = 0x1;
449
450 id->ppaf.blk_offset = 0;
451 id->ppaf.blk_len = 16;
452 id->ppaf.pg_offset = 16;
453 id->ppaf.pg_len = 16;
454 id->ppaf.sect_offset = 32;
455 id->ppaf.sect_len = 8;
456 id->ppaf.pln_offset = 40;
457 id->ppaf.pln_len = 8;
458 id->ppaf.lun_offset = 48;
459 id->ppaf.lun_len = 8;
460 id->ppaf.ch_offset = 56;
461 id->ppaf.ch_len = 8;
462
463 sector_div(size, bs);
464 size >>= 8;
465 grp = &id->grp;
466 grp->mtype = 0;
467 grp->fmtype = 0;
468 grp->num_ch = 1;
469 grp->num_pg = 256;
470 blksize = size;
471 size >>= 16;
472 grp->num_lun = size + 1;
473 sector_div(blksize, grp->num_lun);
474 grp->num_blk = blksize;
475 grp->num_pln = 1;
476
477 grp->fpg_sz = bs;
478 grp->csecs = bs;
479 grp->trdt = 25000;
480 grp->trdm = 25000;
481 grp->tprt = 500000;
482 grp->tprm = 500000;
483 grp->tbet = 1500000;
484 grp->tbem = 1500000;
485 grp->mpos = 0x010101;
486 grp->cpar = hw_queue_depth;
487
488 return 0;
489}
490
491static void *null_lnvm_create_dma_pool(struct nvm_dev *dev, char *name)
492{
493 mempool_t *virtmem_pool;
494
495 virtmem_pool = mempool_create_slab_pool(64, ppa_cache);
496 if (!virtmem_pool) {
497 pr_err("null_blk: Unable to create virtual memory pool\n");
498 return NULL;
499 }
500
501 return virtmem_pool;
502}
503
504static void null_lnvm_destroy_dma_pool(void *pool)
505{
506 mempool_destroy(pool);
507}
508
509static void *null_lnvm_dev_dma_alloc(struct nvm_dev *dev, void *pool,
510 gfp_t mem_flags, dma_addr_t *dma_handler)
511{
512 return mempool_alloc(pool, mem_flags);
513}
514
515static void null_lnvm_dev_dma_free(void *pool, void *entry,
516 dma_addr_t dma_handler)
517{
518 mempool_free(entry, pool);
519}
520
521static struct nvm_dev_ops null_lnvm_dev_ops = {
522 .identity = null_lnvm_id,
523 .submit_io = null_lnvm_submit_io,
524
525 .create_dma_pool = null_lnvm_create_dma_pool,
526 .destroy_dma_pool = null_lnvm_destroy_dma_pool,
527 .dev_dma_alloc = null_lnvm_dev_dma_alloc,
528 .dev_dma_free = null_lnvm_dev_dma_free,
529
530
531 .max_phys_sect = 64,
532};
533
534static int null_nvm_register(struct nullb *nullb)
535{
536 struct nvm_dev *dev;
537 int rv;
538
539 dev = nvm_alloc_dev(0);
540 if (!dev)
541 return -ENOMEM;
542
543 dev->q = nullb->q;
544 memcpy(dev->name, nullb->disk_name, DISK_NAME_LEN);
545 dev->ops = &null_lnvm_dev_ops;
546
547 rv = nvm_register(dev);
548 if (rv) {
549 kfree(dev);
550 return rv;
551 }
552 nullb->ndev = dev;
553 return 0;
554}
555
556static void null_nvm_unregister(struct nullb *nullb)
557{
558 nvm_unregister(nullb->ndev);
559}
560#else
561static int null_nvm_register(struct nullb *nullb)
562{
563 pr_err("null_blk: CONFIG_NVM needs to be enabled for LightNVM\n");
564 return -EINVAL;
565}
566static void null_nvm_unregister(struct nullb *nullb) {}
567#endif
568
569static void null_del_dev(struct nullb *nullb)
570{
571 list_del_init(&nullb->list);
572
573 if (use_lightnvm)
574 null_nvm_unregister(nullb);
575 else
576 del_gendisk(nullb->disk);
577 blk_cleanup_queue(nullb->q);
578 if (queue_mode == NULL_Q_MQ && nullb->tag_set == &nullb->__tag_set)
579 blk_mq_free_tag_set(nullb->tag_set);
580 if (!use_lightnvm)
581 put_disk(nullb->disk);
582 cleanup_queues(nullb);
583 kfree(nullb);
584}
585
586static int null_open(struct block_device *bdev, fmode_t mode)
587{
588 return 0;
589}
590
591static void null_release(struct gendisk *disk, fmode_t mode)
592{
593}
594
595static const struct block_device_operations null_fops = {
596 .owner = THIS_MODULE,
597 .open = null_open,
598 .release = null_release,
599};
600
601static void null_init_queue(struct nullb *nullb, struct nullb_queue *nq)
602{
603 BUG_ON(!nullb);
604 BUG_ON(!nq);
605
606 init_waitqueue_head(&nq->wait);
607 nq->queue_depth = nullb->queue_depth;
608}
609
610static void null_init_queues(struct nullb *nullb)
611{
612 struct request_queue *q = nullb->q;
613 struct blk_mq_hw_ctx *hctx;
614 struct nullb_queue *nq;
615 int i;
616
617 queue_for_each_hw_ctx(q, hctx, i) {
618 if (!hctx->nr_ctx || !hctx->tags)
619 continue;
620 nq = &nullb->queues[i];
621 hctx->driver_data = nq;
622 null_init_queue(nullb, nq);
623 nullb->nr_queues++;
624 }
625}
626
627static int setup_commands(struct nullb_queue *nq)
628{
629 struct nullb_cmd *cmd;
630 int i, tag_size;
631
632 nq->cmds = kzalloc(nq->queue_depth * sizeof(*cmd), GFP_KERNEL);
633 if (!nq->cmds)
634 return -ENOMEM;
635
636 tag_size = ALIGN(nq->queue_depth, BITS_PER_LONG) / BITS_PER_LONG;
637 nq->tag_map = kzalloc(tag_size * sizeof(unsigned long), GFP_KERNEL);
638 if (!nq->tag_map) {
639 kfree(nq->cmds);
640 return -ENOMEM;
641 }
642
643 for (i = 0; i < nq->queue_depth; i++) {
644 cmd = &nq->cmds[i];
645 INIT_LIST_HEAD(&cmd->list);
646 cmd->ll_list.next = NULL;
647 cmd->tag = -1U;
648 }
649
650 return 0;
651}
652
653static int setup_queues(struct nullb *nullb)
654{
655 nullb->queues = kzalloc(submit_queues * sizeof(struct nullb_queue),
656 GFP_KERNEL);
657 if (!nullb->queues)
658 return -ENOMEM;
659
660 nullb->nr_queues = 0;
661 nullb->queue_depth = hw_queue_depth;
662
663 return 0;
664}
665
666static int init_driver_queues(struct nullb *nullb)
667{
668 struct nullb_queue *nq;
669 int i, ret = 0;
670
671 for (i = 0; i < submit_queues; i++) {
672 nq = &nullb->queues[i];
673
674 null_init_queue(nullb, nq);
675
676 ret = setup_commands(nq);
677 if (ret)
678 return ret;
679 nullb->nr_queues++;
680 }
681 return 0;
682}
683
684static int null_gendisk_register(struct nullb *nullb)
685{
686 struct gendisk *disk;
687 sector_t size;
688
689 disk = nullb->disk = alloc_disk_node(1, home_node);
690 if (!disk)
691 return -ENOMEM;
692 size = gb * 1024 * 1024 * 1024ULL;
693 set_capacity(disk, size >> 9);
694
695 disk->flags |= GENHD_FL_EXT_DEVT | GENHD_FL_SUPPRESS_PARTITION_INFO;
696 disk->major = null_major;
697 disk->first_minor = nullb->index;
698 disk->fops = &null_fops;
699 disk->private_data = nullb;
700 disk->queue = nullb->q;
701 strncpy(disk->disk_name, nullb->disk_name, DISK_NAME_LEN);
702
703 add_disk(disk);
704 return 0;
705}
706
707static int null_init_tag_set(struct blk_mq_tag_set *set)
708{
709 set->ops = &null_mq_ops;
710 set->nr_hw_queues = submit_queues;
711 set->queue_depth = hw_queue_depth;
712 set->numa_node = home_node;
713 set->cmd_size = sizeof(struct nullb_cmd);
714 set->flags = BLK_MQ_F_SHOULD_MERGE;
715 set->driver_data = NULL;
716
717 if (blocking)
718 set->flags |= BLK_MQ_F_BLOCKING;
719
720 return blk_mq_alloc_tag_set(set);
721}
722
723static int null_add_dev(void)
724{
725 struct nullb *nullb;
726 int rv;
727
728 nullb = kzalloc_node(sizeof(*nullb), GFP_KERNEL, home_node);
729 if (!nullb) {
730 rv = -ENOMEM;
731 goto out;
732 }
733
734 spin_lock_init(&nullb->lock);
735
736 if (queue_mode == NULL_Q_MQ && use_per_node_hctx)
737 submit_queues = nr_online_nodes;
738
739 rv = setup_queues(nullb);
740 if (rv)
741 goto out_free_nullb;
742
743 if (queue_mode == NULL_Q_MQ) {
744 if (shared_tags) {
745 nullb->tag_set = &tag_set;
746 rv = 0;
747 } else {
748 nullb->tag_set = &nullb->__tag_set;
749 rv = null_init_tag_set(nullb->tag_set);
750 }
751
752 if (rv)
753 goto out_cleanup_queues;
754
755 nullb->q = blk_mq_init_queue(nullb->tag_set);
756 if (IS_ERR(nullb->q)) {
757 rv = -ENOMEM;
758 goto out_cleanup_tags;
759 }
760 null_init_queues(nullb);
761 } else if (queue_mode == NULL_Q_BIO) {
762 nullb->q = blk_alloc_queue_node(GFP_KERNEL, home_node);
763 if (!nullb->q) {
764 rv = -ENOMEM;
765 goto out_cleanup_queues;
766 }
767 blk_queue_make_request(nullb->q, null_queue_bio);
768 rv = init_driver_queues(nullb);
769 if (rv)
770 goto out_cleanup_blk_queue;
771 } else {
772 nullb->q = blk_init_queue_node(null_request_fn, &nullb->lock, home_node);
773 if (!nullb->q) {
774 rv = -ENOMEM;
775 goto out_cleanup_queues;
776 }
777 blk_queue_prep_rq(nullb->q, null_rq_prep_fn);
778 blk_queue_softirq_done(nullb->q, null_softirq_done_fn);
779 rv = init_driver_queues(nullb);
780 if (rv)
781 goto out_cleanup_blk_queue;
782 }
783
784 nullb->q->queuedata = nullb;
785 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, nullb->q);
786 queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, nullb->q);
787
788 mutex_lock(&lock);
789 nullb->index = nullb_indexes++;
790 mutex_unlock(&lock);
791
792 blk_queue_logical_block_size(nullb->q, bs);
793 blk_queue_physical_block_size(nullb->q, bs);
794
795 sprintf(nullb->disk_name, "nullb%d", nullb->index);
796
797 if (use_lightnvm)
798 rv = null_nvm_register(nullb);
799 else
800 rv = null_gendisk_register(nullb);
801
802 if (rv)
803 goto out_cleanup_blk_queue;
804
805 mutex_lock(&lock);
806 list_add_tail(&nullb->list, &nullb_list);
807 mutex_unlock(&lock);
808
809 return 0;
810out_cleanup_blk_queue:
811 blk_cleanup_queue(nullb->q);
812out_cleanup_tags:
813 if (queue_mode == NULL_Q_MQ && nullb->tag_set == &nullb->__tag_set)
814 blk_mq_free_tag_set(nullb->tag_set);
815out_cleanup_queues:
816 cleanup_queues(nullb);
817out_free_nullb:
818 kfree(nullb);
819out:
820 return rv;
821}
822
823static int __init null_init(void)
824{
825 int ret = 0;
826 unsigned int i;
827 struct nullb *nullb;
828
829 if (bs > PAGE_SIZE) {
830 pr_warn("null_blk: invalid block size\n");
831 pr_warn("null_blk: defaults block size to %lu\n", PAGE_SIZE);
832 bs = PAGE_SIZE;
833 }
834
835 if (use_lightnvm && bs != 4096) {
836 pr_warn("null_blk: LightNVM only supports 4k block size\n");
837 pr_warn("null_blk: defaults block size to 4k\n");
838 bs = 4096;
839 }
840
841 if (use_lightnvm && queue_mode != NULL_Q_MQ) {
842 pr_warn("null_blk: LightNVM only supported for blk-mq\n");
843 pr_warn("null_blk: defaults queue mode to blk-mq\n");
844 queue_mode = NULL_Q_MQ;
845 }
846
847 if (queue_mode == NULL_Q_MQ && use_per_node_hctx) {
848 if (submit_queues < nr_online_nodes) {
849 pr_warn("null_blk: submit_queues param is set to %u.",
850 nr_online_nodes);
851 submit_queues = nr_online_nodes;
852 }
853 } else if (submit_queues > nr_cpu_ids)
854 submit_queues = nr_cpu_ids;
855 else if (!submit_queues)
856 submit_queues = 1;
857
858 if (queue_mode == NULL_Q_MQ && shared_tags) {
859 ret = null_init_tag_set(&tag_set);
860 if (ret)
861 return ret;
862 }
863
864 mutex_init(&lock);
865
866 null_major = register_blkdev(0, "nullb");
867 if (null_major < 0) {
868 ret = null_major;
869 goto err_tagset;
870 }
871
872 if (use_lightnvm) {
873 ppa_cache = kmem_cache_create("ppa_cache", 64 * sizeof(u64),
874 0, 0, NULL);
875 if (!ppa_cache) {
876 pr_err("null_blk: unable to create ppa cache\n");
877 ret = -ENOMEM;
878 goto err_ppa;
879 }
880 }
881
882 for (i = 0; i < nr_devices; i++) {
883 ret = null_add_dev();
884 if (ret)
885 goto err_dev;
886 }
887
888 pr_info("null: module loaded\n");
889 return 0;
890
891err_dev:
892 while (!list_empty(&nullb_list)) {
893 nullb = list_entry(nullb_list.next, struct nullb, list);
894 null_del_dev(nullb);
895 }
896 kmem_cache_destroy(ppa_cache);
897err_ppa:
898 unregister_blkdev(null_major, "nullb");
899err_tagset:
900 if (queue_mode == NULL_Q_MQ && shared_tags)
901 blk_mq_free_tag_set(&tag_set);
902 return ret;
903}
904
905static void __exit null_exit(void)
906{
907 struct nullb *nullb;
908
909 unregister_blkdev(null_major, "nullb");
910
911 mutex_lock(&lock);
912 while (!list_empty(&nullb_list)) {
913 nullb = list_entry(nullb_list.next, struct nullb, list);
914 null_del_dev(nullb);
915 }
916 mutex_unlock(&lock);
917
918 if (queue_mode == NULL_Q_MQ && shared_tags)
919 blk_mq_free_tag_set(&tag_set);
920
921 kmem_cache_destroy(ppa_cache);
922}
923
924module_init(null_init);
925module_exit(null_exit);
926
927MODULE_AUTHOR("Jens Axboe <jaxboe@fusionio.com>");
928MODULE_LICENSE("GPL");
929
