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 blk_mq_tag_set tag_set;
38	struct hrtimer timer;
39	unsigned int queue_depth;
40	spinlock_t lock;
41
42	struct nullb_queue *queues;
43	unsigned int nr_queues;
44	char disk_name[DISK_NAME_LEN];
45};
46
47static LIST_HEAD(nullb_list);
48static struct mutex lock;
49static int null_major;
50static int nullb_indexes;
51static struct kmem_cache *ppa_cache;
52
53enum {
54	NULL_IRQ_NONE		= 0,
55	NULL_IRQ_SOFTIRQ	= 1,
56	NULL_IRQ_TIMER		= 2,
57};
58
59enum {
60	NULL_Q_BIO		= 0,
61	NULL_Q_RQ		= 1,
62	NULL_Q_MQ		= 2,
63};
64
65static int submit_queues;
66module_param(submit_queues, int, S_IRUGO);
67MODULE_PARM_DESC(submit_queues, "Number of submission queues");
68
69static int home_node = NUMA_NO_NODE;
70module_param(home_node, int, S_IRUGO);
71MODULE_PARM_DESC(home_node, "Home node for the device");
72
73static int queue_mode = NULL_Q_MQ;
74
75static int null_param_store_val(const char *str, int *val, int min, int max)
76{
77	int ret, new_val;
78
79	ret = kstrtoint(str, 10, &new_val);
80	if (ret)
81		return -EINVAL;
82
83	if (new_val < min || new_val > max)
84		return -EINVAL;
85
86	*val = new_val;
87	return 0;
88}
89
90static int null_set_queue_mode(const char *str, const struct kernel_param *kp)
91{
92	return null_param_store_val(str, &queue_mode, NULL_Q_BIO, NULL_Q_MQ);
93}
94
95static const struct kernel_param_ops null_queue_mode_param_ops = {
96	.set	= null_set_queue_mode,
97	.get	= param_get_int,
98};
99
100device_param_cb(queue_mode, &null_queue_mode_param_ops, &queue_mode, S_IRUGO);
101MODULE_PARM_DESC(queue_mode, "Block interface to use (0=bio,1=rq,2=multiqueue)");
102
103static int gb = 250;
104module_param(gb, int, S_IRUGO);
105MODULE_PARM_DESC(gb, "Size in GB");
106
107static int bs = 512;
108module_param(bs, int, S_IRUGO);
109MODULE_PARM_DESC(bs, "Block size (in bytes)");
110
111static int nr_devices = 2;
112module_param(nr_devices, int, S_IRUGO);
113MODULE_PARM_DESC(nr_devices, "Number of devices to register");
114
115static bool use_lightnvm;
116module_param(use_lightnvm, bool, S_IRUGO);
117MODULE_PARM_DESC(use_lightnvm, "Register as a LightNVM device");
118
119static int irqmode = NULL_IRQ_SOFTIRQ;
120
121static int null_set_irqmode(const char *str, const struct kernel_param *kp)
122{
123	return null_param_store_val(str, &irqmode, NULL_IRQ_NONE,
124					NULL_IRQ_TIMER);
125}
126
127static const struct kernel_param_ops null_irqmode_param_ops = {
128	.set	= null_set_irqmode,
129	.get	= param_get_int,
130};
131
132device_param_cb(irqmode, &null_irqmode_param_ops, &irqmode, S_IRUGO);
133MODULE_PARM_DESC(irqmode, "IRQ completion handler. 0-none, 1-softirq, 2-timer");
134
135static unsigned long completion_nsec = 10000;
136module_param(completion_nsec, ulong, S_IRUGO);
137MODULE_PARM_DESC(completion_nsec, "Time in ns to complete a request in hardware. Default: 10,000ns");
138
139static int hw_queue_depth = 64;
140module_param(hw_queue_depth, int, S_IRUGO);
141MODULE_PARM_DESC(hw_queue_depth, "Queue depth for each hardware queue. Default: 64");
142
143static bool use_per_node_hctx = false;
144module_param(use_per_node_hctx, bool, S_IRUGO);
145MODULE_PARM_DESC(use_per_node_hctx, "Use per-node allocation for hardware context queues. Default: false");
146
147static void put_tag(struct nullb_queue *nq, unsigned int tag)
148{
149	clear_bit_unlock(tag, nq->tag_map);
150
151	if (waitqueue_active(&nq->wait))
152		wake_up(&nq->wait);
153}
154
155static unsigned int get_tag(struct nullb_queue *nq)
156{
157	unsigned int tag;
158
159	do {
160		tag = find_first_zero_bit(nq->tag_map, nq->queue_depth);
161		if (tag >= nq->queue_depth)
162			return -1U;
163	} while (test_and_set_bit_lock(tag, nq->tag_map));
164
165	return tag;
166}
167
168static void free_cmd(struct nullb_cmd *cmd)
169{
170	put_tag(cmd->nq, cmd->tag);
171}
172
173static enum hrtimer_restart null_cmd_timer_expired(struct hrtimer *timer);
174
175static struct nullb_cmd *__alloc_cmd(struct nullb_queue *nq)
176{
177	struct nullb_cmd *cmd;
178	unsigned int tag;
179
180	tag = get_tag(nq);
181	if (tag != -1U) {
182		cmd = &nq->cmds[tag];
183		cmd->tag = tag;
184		cmd->nq = nq;
185		if (irqmode == NULL_IRQ_TIMER) {
186			hrtimer_init(&cmd->timer, CLOCK_MONOTONIC,
187				     HRTIMER_MODE_REL);
188			cmd->timer.function = null_cmd_timer_expired;
189		}
190		return cmd;
191	}
192
193	return NULL;
194}
195
196static struct nullb_cmd *alloc_cmd(struct nullb_queue *nq, int can_wait)
197{
198	struct nullb_cmd *cmd;
199	DEFINE_WAIT(wait);
200
201	cmd = __alloc_cmd(nq);
202	if (cmd || !can_wait)
203		return cmd;
204
205	do {
206		prepare_to_wait(&nq->wait, &wait, TASK_UNINTERRUPTIBLE);
207		cmd = __alloc_cmd(nq);
208		if (cmd)
209			break;
210
211		io_schedule();
212	} while (1);
213
214	finish_wait(&nq->wait, &wait);
215	return cmd;
216}
217
218static void end_cmd(struct nullb_cmd *cmd)
219{
220	struct request_queue *q = NULL;
221
222	if (cmd->rq)
223		q = cmd->rq->q;
224
225	switch (queue_mode)  {
226	case NULL_Q_MQ:
227		blk_mq_end_request(cmd->rq, 0);
228		return;
229	case NULL_Q_RQ:
230		INIT_LIST_HEAD(&cmd->rq->queuelist);
231		blk_end_request_all(cmd->rq, 0);
232		break;
233	case NULL_Q_BIO:
234		bio_endio(cmd->bio);
235		break;
236	}
237
238	free_cmd(cmd);
239
240	/* Restart queue if needed, as we are freeing a tag */
241	if (queue_mode == NULL_Q_RQ && blk_queue_stopped(q)) {
242		unsigned long flags;
243
244		spin_lock_irqsave(q->queue_lock, flags);
245		blk_start_queue_async(q);
246		spin_unlock_irqrestore(q->queue_lock, flags);
247	}
248}
249
250static enum hrtimer_restart null_cmd_timer_expired(struct hrtimer *timer)
251{
252	end_cmd(container_of(timer, struct nullb_cmd, timer));
253
254	return HRTIMER_NORESTART;
255}
256
257static void null_cmd_end_timer(struct nullb_cmd *cmd)
258{
259	ktime_t kt = ktime_set(0, completion_nsec);
260
261	hrtimer_start(&cmd->timer, kt, HRTIMER_MODE_REL);
262}
263
264static void null_softirq_done_fn(struct request *rq)
265{
266	if (queue_mode == NULL_Q_MQ)
267		end_cmd(blk_mq_rq_to_pdu(rq));
268	else
269		end_cmd(rq->special);
270}
271
272static inline void null_handle_cmd(struct nullb_cmd *cmd)
273{
274	/* Complete IO by inline, softirq or timer */
275	switch (irqmode) {
276	case NULL_IRQ_SOFTIRQ:
277		switch (queue_mode)  {
278		case NULL_Q_MQ:
279			blk_mq_complete_request(cmd->rq, cmd->rq->errors);
280			break;
281		case NULL_Q_RQ:
282			blk_complete_request(cmd->rq);
283			break;
284		case NULL_Q_BIO:
285			/*
286			 * XXX: no proper submitting cpu information available.
287			 */
288			end_cmd(cmd);
289			break;
290		}
291		break;
292	case NULL_IRQ_NONE:
293		end_cmd(cmd);
294		break;
295	case NULL_IRQ_TIMER:
296		null_cmd_end_timer(cmd);
297		break;
298	}
299}
300
301static struct nullb_queue *nullb_to_queue(struct nullb *nullb)
302{
303	int index = 0;
304
305	if (nullb->nr_queues != 1)
306		index = raw_smp_processor_id() / ((nr_cpu_ids + nullb->nr_queues - 1) / nullb->nr_queues);
307
308	return &nullb->queues[index];
309}
310
311static blk_qc_t null_queue_bio(struct request_queue *q, struct bio *bio)
312{
313	struct nullb *nullb = q->queuedata;
314	struct nullb_queue *nq = nullb_to_queue(nullb);
315	struct nullb_cmd *cmd;
316
317	cmd = alloc_cmd(nq, 1);
318	cmd->bio = bio;
319
320	null_handle_cmd(cmd);
321	return BLK_QC_T_NONE;
322}
323
324static int null_rq_prep_fn(struct request_queue *q, struct request *req)
325{
326	struct nullb *nullb = q->queuedata;
327	struct nullb_queue *nq = nullb_to_queue(nullb);
328	struct nullb_cmd *cmd;
329
330	cmd = alloc_cmd(nq, 0);
331	if (cmd) {
332		cmd->rq = req;
333		req->special = cmd;
334		return BLKPREP_OK;
335	}
336	blk_stop_queue(q);
337
338	return BLKPREP_DEFER;
339}
340
341static void null_request_fn(struct request_queue *q)
342{
343	struct request *rq;
344
345	while ((rq = blk_fetch_request(q)) != NULL) {
346		struct nullb_cmd *cmd = rq->special;
347
348		spin_unlock_irq(q->queue_lock);
349		null_handle_cmd(cmd);
350		spin_lock_irq(q->queue_lock);
351	}
352}
353
354static int null_queue_rq(struct blk_mq_hw_ctx *hctx,
355			 const struct blk_mq_queue_data *bd)
356{
357	struct nullb_cmd *cmd = blk_mq_rq_to_pdu(bd->rq);
358
359	if (irqmode == NULL_IRQ_TIMER) {
360		hrtimer_init(&cmd->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
361		cmd->timer.function = null_cmd_timer_expired;
362	}
363	cmd->rq = bd->rq;
364	cmd->nq = hctx->driver_data;
365
366	blk_mq_start_request(bd->rq);
367
368	null_handle_cmd(cmd);
369	return BLK_MQ_RQ_QUEUE_OK;
370}
371
372static void null_init_queue(struct nullb *nullb, struct nullb_queue *nq)
373{
374	BUG_ON(!nullb);
375	BUG_ON(!nq);
376
377	init_waitqueue_head(&nq->wait);
378	nq->queue_depth = nullb->queue_depth;
379}
380
381static int null_init_hctx(struct blk_mq_hw_ctx *hctx, void *data,
382			  unsigned int index)
383{
384	struct nullb *nullb = data;
385	struct nullb_queue *nq = &nullb->queues[index];
386
387	hctx->driver_data = nq;
388	null_init_queue(nullb, nq);
389	nullb->nr_queues++;
390
391	return 0;
392}
393
394static struct blk_mq_ops null_mq_ops = {
395	.queue_rq       = null_queue_rq,
396	.map_queue      = blk_mq_map_queue,
397	.init_hctx	= null_init_hctx,
398	.complete	= null_softirq_done_fn,
399};
400
401static void cleanup_queue(struct nullb_queue *nq)
402{
403	kfree(nq->tag_map);
404	kfree(nq->cmds);
405}
406
407static void cleanup_queues(struct nullb *nullb)
408{
409	int i;
410
411	for (i = 0; i < nullb->nr_queues; i++)
412		cleanup_queue(&nullb->queues[i]);
413
414	kfree(nullb->queues);
415}
416
417static void null_del_dev(struct nullb *nullb)
418{
419	list_del_init(&nullb->list);
420
421	if (use_lightnvm)
422		nvm_unregister(nullb->disk_name);
423	else
424		del_gendisk(nullb->disk);
425	blk_cleanup_queue(nullb->q);
426	if (queue_mode == NULL_Q_MQ)
427		blk_mq_free_tag_set(&nullb->tag_set);
428	if (!use_lightnvm)
429		put_disk(nullb->disk);
430	cleanup_queues(nullb);
431	kfree(nullb);
432}
433
434#ifdef CONFIG_NVM
435
436static void null_lnvm_end_io(struct request *rq, int error)
437{
438	struct nvm_rq *rqd = rq->end_io_data;
439	struct nvm_dev *dev = rqd->dev;
440
441	dev->mt->end_io(rqd, error);
442
443	blk_put_request(rq);
444}
445
446static int null_lnvm_submit_io(struct nvm_dev *dev, struct nvm_rq *rqd)
447{
448	struct request_queue *q = dev->q;
449	struct request *rq;
450	struct bio *bio = rqd->bio;
451
452	rq = blk_mq_alloc_request(q, bio_rw(bio), GFP_KERNEL, 0);
453	if (IS_ERR(rq))
454		return -ENOMEM;
455
456	rq->cmd_type = REQ_TYPE_DRV_PRIV;
457	rq->__sector = bio->bi_iter.bi_sector;
458	rq->ioprio = bio_prio(bio);
459
460	if (bio_has_data(bio))
461		rq->nr_phys_segments = bio_phys_segments(q, bio);
462
463	rq->__data_len = bio->bi_iter.bi_size;
464	rq->bio = rq->biotail = bio;
465
466	rq->end_io_data = rqd;
467
468	blk_execute_rq_nowait(q, NULL, rq, 0, null_lnvm_end_io);
469
470	return 0;
471}
472
473static int null_lnvm_id(struct nvm_dev *dev, struct nvm_id *id)
474{
475	sector_t size = gb * 1024 * 1024 * 1024ULL;
476	sector_t blksize;
477	struct nvm_id_group *grp;
478
479	id->ver_id = 0x1;
480	id->vmnt = 0;
481	id->cgrps = 1;
482	id->cap = 0x3;
483	id->dom = 0x1;
484
485	id->ppaf.blk_offset = 0;
486	id->ppaf.blk_len = 16;
487	id->ppaf.pg_offset = 16;
488	id->ppaf.pg_len = 16;
489	id->ppaf.sect_offset = 32;
490	id->ppaf.sect_len = 8;
491	id->ppaf.pln_offset = 40;
492	id->ppaf.pln_len = 8;
493	id->ppaf.lun_offset = 48;
494	id->ppaf.lun_len = 8;
495	id->ppaf.ch_offset = 56;
496	id->ppaf.ch_len = 8;
497
498	do_div(size, bs); /* convert size to pages */
499	do_div(size, 256); /* concert size to pgs pr blk */
500	grp = &id->groups[0];
501	grp->mtype = 0;
502	grp->fmtype = 0;
503	grp->num_ch = 1;
504	grp->num_pg = 256;
505	blksize = size;
506	do_div(size, (1 << 16));
507	grp->num_lun = size + 1;
508	do_div(blksize, grp->num_lun);
509	grp->num_blk = blksize;
510	grp->num_pln = 1;
511
512	grp->fpg_sz = bs;
513	grp->csecs = bs;
514	grp->trdt = 25000;
515	grp->trdm = 25000;
516	grp->tprt = 500000;
517	grp->tprm = 500000;
518	grp->tbet = 1500000;
519	grp->tbem = 1500000;
520	grp->mpos = 0x010101; /* single plane rwe */
521	grp->cpar = hw_queue_depth;
522
523	return 0;
524}
525
526static void *null_lnvm_create_dma_pool(struct nvm_dev *dev, char *name)
527{
528	mempool_t *virtmem_pool;
529
530	virtmem_pool = mempool_create_slab_pool(64, ppa_cache);
531	if (!virtmem_pool) {
532		pr_err("null_blk: Unable to create virtual memory pool\n");
533		return NULL;
534	}
535
536	return virtmem_pool;
537}
538
539static void null_lnvm_destroy_dma_pool(void *pool)
540{
541	mempool_destroy(pool);
542}
543
544static void *null_lnvm_dev_dma_alloc(struct nvm_dev *dev, void *pool,
545				gfp_t mem_flags, dma_addr_t *dma_handler)
546{
547	return mempool_alloc(pool, mem_flags);
548}
549
550static void null_lnvm_dev_dma_free(void *pool, void *entry,
551							dma_addr_t dma_handler)
552{
553	mempool_free(entry, pool);
554}
555
556static struct nvm_dev_ops null_lnvm_dev_ops = {
557	.identity		= null_lnvm_id,
558	.submit_io		= null_lnvm_submit_io,
559
560	.create_dma_pool	= null_lnvm_create_dma_pool,
561	.destroy_dma_pool	= null_lnvm_destroy_dma_pool,
562	.dev_dma_alloc		= null_lnvm_dev_dma_alloc,
563	.dev_dma_free		= null_lnvm_dev_dma_free,
564
565	/* Simulate nvme protocol restriction */
566	.max_phys_sect		= 64,
567};
568#else
569static struct nvm_dev_ops null_lnvm_dev_ops;
570#endif /* CONFIG_NVM */
571
572static int null_open(struct block_device *bdev, fmode_t mode)
573{
574	return 0;
575}
576
577static void null_release(struct gendisk *disk, fmode_t mode)
578{
579}
580
581static const struct block_device_operations null_fops = {
582	.owner =	THIS_MODULE,
583	.open =		null_open,
584	.release =	null_release,
585};
586
587static int setup_commands(struct nullb_queue *nq)
588{
589	struct nullb_cmd *cmd;
590	int i, tag_size;
591
592	nq->cmds = kzalloc(nq->queue_depth * sizeof(*cmd), GFP_KERNEL);
593	if (!nq->cmds)
594		return -ENOMEM;
595
596	tag_size = ALIGN(nq->queue_depth, BITS_PER_LONG) / BITS_PER_LONG;
597	nq->tag_map = kzalloc(tag_size * sizeof(unsigned long), GFP_KERNEL);
598	if (!nq->tag_map) {
599		kfree(nq->cmds);
600		return -ENOMEM;
601	}
602
603	for (i = 0; i < nq->queue_depth; i++) {
604		cmd = &nq->cmds[i];
605		INIT_LIST_HEAD(&cmd->list);
606		cmd->ll_list.next = NULL;
607		cmd->tag = -1U;
608	}
609
610	return 0;
611}
612
613static int setup_queues(struct nullb *nullb)
614{
615	nullb->queues = kzalloc(submit_queues * sizeof(struct nullb_queue),
616								GFP_KERNEL);
617	if (!nullb->queues)
618		return -ENOMEM;
619
620	nullb->nr_queues = 0;
621	nullb->queue_depth = hw_queue_depth;
622
623	return 0;
624}
625
626static int init_driver_queues(struct nullb *nullb)
627{
628	struct nullb_queue *nq;
629	int i, ret = 0;
630
631	for (i = 0; i < submit_queues; i++) {
632		nq = &nullb->queues[i];
633
634		null_init_queue(nullb, nq);
635
636		ret = setup_commands(nq);
637		if (ret)
638			return ret;
639		nullb->nr_queues++;
640	}
641	return 0;
642}
643
644static int null_add_dev(void)
645{
646	struct gendisk *disk;
647	struct nullb *nullb;
648	sector_t size;
649	int rv;
650
651	nullb = kzalloc_node(sizeof(*nullb), GFP_KERNEL, home_node);
652	if (!nullb) {
653		rv = -ENOMEM;
654		goto out;
655	}
656
657	spin_lock_init(&nullb->lock);
658
659	if (queue_mode == NULL_Q_MQ && use_per_node_hctx)
660		submit_queues = nr_online_nodes;
661
662	rv = setup_queues(nullb);
663	if (rv)
664		goto out_free_nullb;
665
666	if (queue_mode == NULL_Q_MQ) {
667		nullb->tag_set.ops = &null_mq_ops;
668		nullb->tag_set.nr_hw_queues = submit_queues;
669		nullb->tag_set.queue_depth = hw_queue_depth;
670		nullb->tag_set.numa_node = home_node;
671		nullb->tag_set.cmd_size	= sizeof(struct nullb_cmd);
672		nullb->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
673		nullb->tag_set.driver_data = nullb;
674
675		rv = blk_mq_alloc_tag_set(&nullb->tag_set);
676		if (rv)
677			goto out_cleanup_queues;
678
679		nullb->q = blk_mq_init_queue(&nullb->tag_set);
680		if (IS_ERR(nullb->q)) {
681			rv = -ENOMEM;
682			goto out_cleanup_tags;
683		}
684	} else if (queue_mode == NULL_Q_BIO) {
685		nullb->q = blk_alloc_queue_node(GFP_KERNEL, home_node);
686		if (!nullb->q) {
687			rv = -ENOMEM;
688			goto out_cleanup_queues;
689		}
690		blk_queue_make_request(nullb->q, null_queue_bio);
691		rv = init_driver_queues(nullb);
692		if (rv)
693			goto out_cleanup_blk_queue;
694	} else {
695		nullb->q = blk_init_queue_node(null_request_fn, &nullb->lock, home_node);
696		if (!nullb->q) {
697			rv = -ENOMEM;
698			goto out_cleanup_queues;
699		}
700		blk_queue_prep_rq(nullb->q, null_rq_prep_fn);
701		blk_queue_softirq_done(nullb->q, null_softirq_done_fn);
702		rv = init_driver_queues(nullb);
703		if (rv)
704			goto out_cleanup_blk_queue;
705	}
706
707	nullb->q->queuedata = nullb;
708	queue_flag_set_unlocked(QUEUE_FLAG_NONROT, nullb->q);
709	queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, nullb->q);
710
711
712	mutex_lock(&lock);
713	list_add_tail(&nullb->list, &nullb_list);
714	nullb->index = nullb_indexes++;
715	mutex_unlock(&lock);
716
717	blk_queue_logical_block_size(nullb->q, bs);
718	blk_queue_physical_block_size(nullb->q, bs);
719
720	sprintf(nullb->disk_name, "nullb%d", nullb->index);
721
722	if (use_lightnvm) {
723		rv = nvm_register(nullb->q, nullb->disk_name,
724							&null_lnvm_dev_ops);
725		if (rv)
726			goto out_cleanup_blk_queue;
727		goto done;
728	}
729
730	disk = nullb->disk = alloc_disk_node(1, home_node);
731	if (!disk) {
732		rv = -ENOMEM;
733		goto out_cleanup_lightnvm;
734	}
735	size = gb * 1024 * 1024 * 1024ULL;
736	set_capacity(disk, size >> 9);
737
738	disk->flags |= GENHD_FL_EXT_DEVT | GENHD_FL_SUPPRESS_PARTITION_INFO;
739	disk->major		= null_major;
740	disk->first_minor	= nullb->index;
741	disk->fops		= &null_fops;
742	disk->private_data	= nullb;
743	disk->queue		= nullb->q;
744	strncpy(disk->disk_name, nullb->disk_name, DISK_NAME_LEN);
745
746	add_disk(disk);
747done:
748	return 0;
749
750out_cleanup_lightnvm:
751	if (use_lightnvm)
752		nvm_unregister(nullb->disk_name);
753out_cleanup_blk_queue:
754	blk_cleanup_queue(nullb->q);
755out_cleanup_tags:
756	if (queue_mode == NULL_Q_MQ)
757		blk_mq_free_tag_set(&nullb->tag_set);
758out_cleanup_queues:
759	cleanup_queues(nullb);
760out_free_nullb:
761	kfree(nullb);
762out:
763	return rv;
764}
765
766static int __init null_init(void)
767{
768	int ret = 0;
769	unsigned int i;
770	struct nullb *nullb;
771
772	if (bs > PAGE_SIZE) {
773		pr_warn("null_blk: invalid block size\n");
774		pr_warn("null_blk: defaults block size to %lu\n", PAGE_SIZE);
775		bs = PAGE_SIZE;
776	}
777
778	if (use_lightnvm && bs != 4096) {
779		pr_warn("null_blk: LightNVM only supports 4k block size\n");
780		pr_warn("null_blk: defaults block size to 4k\n");
781		bs = 4096;
782	}
783
784	if (use_lightnvm && queue_mode != NULL_Q_MQ) {
785		pr_warn("null_blk: LightNVM only supported for blk-mq\n");
786		pr_warn("null_blk: defaults queue mode to blk-mq\n");
787		queue_mode = NULL_Q_MQ;
788	}
789
790	if (queue_mode == NULL_Q_MQ && use_per_node_hctx) {
791		if (submit_queues < nr_online_nodes) {
792			pr_warn("null_blk: submit_queues param is set to %u.",
793							nr_online_nodes);
794			submit_queues = nr_online_nodes;
795		}
796	} else if (submit_queues > nr_cpu_ids)
797		submit_queues = nr_cpu_ids;
798	else if (!submit_queues)
799		submit_queues = 1;
800
801	mutex_init(&lock);
802
803	null_major = register_blkdev(0, "nullb");
804	if (null_major < 0)
805		return null_major;
806
807	if (use_lightnvm) {
808		ppa_cache = kmem_cache_create("ppa_cache", 64 * sizeof(u64),
809								0, 0, NULL);
810		if (!ppa_cache) {
811			pr_err("null_blk: unable to create ppa cache\n");
812			ret = -ENOMEM;
813			goto err_ppa;
814		}
815	}
816
817	for (i = 0; i < nr_devices; i++) {
818		ret = null_add_dev();
819		if (ret)
820			goto err_dev;
821	}
822
823	pr_info("null: module loaded\n");
824	return 0;
825
826err_dev:
827	while (!list_empty(&nullb_list)) {
828		nullb = list_entry(nullb_list.next, struct nullb, list);
829		null_del_dev(nullb);
830	}
831	kmem_cache_destroy(ppa_cache);
832err_ppa:
833	unregister_blkdev(null_major, "nullb");
834	return ret;
835}
836
837static void __exit null_exit(void)
838{
839	struct nullb *nullb;
840
841	unregister_blkdev(null_major, "nullb");
842
843	mutex_lock(&lock);
844	while (!list_empty(&nullb_list)) {
845		nullb = list_entry(nullb_list.next, struct nullb, list);
846		null_del_dev(nullb);
847	}
848	mutex_unlock(&lock);
849
850	kmem_cache_destroy(ppa_cache);
851}
852
853module_init(null_init);
854module_exit(null_exit);
855
856MODULE_AUTHOR("Jens Axboe <jaxboe@fusionio.com>");
857MODULE_LICENSE("GPL");
858