1 // SPDX-License-Identifier: GPL-2.0-only
3 * Add configfs and memory store: Kyungchan Koh <kkc6196@fb.com> and
4 * Shaohua Li <shli@fb.com>
6 #include <linux/module.h>
8 #include <linux/moduleparam.h>
9 #include <linux/sched.h>
11 #include <linux/init.h>
14 #define PAGE_SECTORS_SHIFT (PAGE_SHIFT - SECTOR_SHIFT)
15 #define PAGE_SECTORS (1 << PAGE_SECTORS_SHIFT)
16 #define SECTOR_MASK (PAGE_SECTORS - 1)
20 #define TICKS_PER_SEC 50ULL
21 #define TIMER_INTERVAL (NSEC_PER_SEC / TICKS_PER_SEC)
23 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
24 static DECLARE_FAULT_ATTR(null_timeout_attr);
25 static DECLARE_FAULT_ATTR(null_requeue_attr);
26 static DECLARE_FAULT_ATTR(null_init_hctx_attr);
29 static inline u64 mb_per_tick(int mbps)
31 return (1 << 20) / TICKS_PER_SEC * ((u64) mbps);
35 * Status flags for nullb_device.
37 * CONFIGURED: Device has been configured and turned on. Cannot reconfigure.
38 * UP: Device is currently on and visible in userspace.
39 * THROTTLED: Device is being throttled.
40 * CACHE: Device is using a write-back cache.
42 enum nullb_device_flags {
43 NULLB_DEV_FL_CONFIGURED = 0,
45 NULLB_DEV_FL_THROTTLED = 2,
46 NULLB_DEV_FL_CACHE = 3,
49 #define MAP_SZ ((PAGE_SIZE >> SECTOR_SHIFT) + 2)
51 * nullb_page is a page in memory for nullb devices.
53 * @page: The page holding the data.
54 * @bitmap: The bitmap represents which sector in the page has data.
55 * Each bit represents one block size. For example, sector 8
56 * will use the 7th bit
57 * The highest 2 bits of bitmap are for special purpose. LOCK means the cache
58 * page is being flushing to storage. FREE means the cache page is freed and
59 * should be skipped from flushing to storage. Please see
60 * null_make_cache_space
64 DECLARE_BITMAP(bitmap, MAP_SZ);
66 #define NULLB_PAGE_LOCK (MAP_SZ - 1)
67 #define NULLB_PAGE_FREE (MAP_SZ - 2)
69 static LIST_HEAD(nullb_list);
70 static struct mutex lock;
71 static int null_major;
72 static DEFINE_IDA(nullb_indexes);
73 static struct blk_mq_tag_set tag_set;
87 static bool g_virt_boundary = false;
88 module_param_named(virt_boundary, g_virt_boundary, bool, 0444);
89 MODULE_PARM_DESC(virt_boundary, "Require a virtual boundary for the device. Default: False");
91 static int g_no_sched;
92 module_param_named(no_sched, g_no_sched, int, 0444);
93 MODULE_PARM_DESC(no_sched, "No io scheduler");
95 static int g_submit_queues = 1;
96 module_param_named(submit_queues, g_submit_queues, int, 0444);
97 MODULE_PARM_DESC(submit_queues, "Number of submission queues");
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");
103 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
105 * For more details about fault injection, please refer to
106 * Documentation/fault-injection/fault-injection.rst.
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>");
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>");
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>");
121 static int g_queue_mode = NULL_Q_MQ;
123 static int null_param_store_val(const char *str, int *val, int min, int max)
127 ret = kstrtoint(str, 10, &new_val);
131 if (new_val < min || new_val > max)
138 static int null_set_queue_mode(const char *str, const struct kernel_param *kp)
140 return null_param_store_val(str, &g_queue_mode, NULL_Q_BIO, NULL_Q_MQ);
143 static const struct kernel_param_ops null_queue_mode_param_ops = {
144 .set = null_set_queue_mode,
145 .get = param_get_int,
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)");
151 static int g_gb = 250;
152 module_param_named(gb, g_gb, int, 0444);
153 MODULE_PARM_DESC(gb, "Size in GB");
155 static int g_bs = 512;
156 module_param_named(bs, g_bs, int, 0444);
157 MODULE_PARM_DESC(bs, "Block size (in bytes)");
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)");
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");
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");
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");
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");
179 static int g_irqmode = NULL_IRQ_SOFTIRQ;
181 static int null_set_irqmode(const char *str, const struct kernel_param *kp)
183 return null_param_store_val(str, &g_irqmode, NULL_IRQ_NONE,
187 static const struct kernel_param_ops null_irqmode_param_ops = {
188 .set = null_set_irqmode,
189 .get = param_get_int,
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");
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");
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");
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");
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");
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");
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");
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");
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)");
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)");
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);
237 static inline struct nullb_device *to_nullb_device(struct config_item *item)
239 return item ? container_of(item, struct nullb_device, item) : NULL;
242 static inline ssize_t nullb_device_uint_attr_show(unsigned int val, char *page)
244 return snprintf(page, PAGE_SIZE, "%u\n", val);
247 static inline ssize_t nullb_device_ulong_attr_show(unsigned long val,
250 return snprintf(page, PAGE_SIZE, "%lu\n", val);
253 static inline ssize_t nullb_device_bool_attr_show(bool val, char *page)
255 return snprintf(page, PAGE_SIZE, "%u\n", val);
258 static ssize_t nullb_device_uint_attr_store(unsigned int *val,
259 const char *page, size_t count)
264 result = kstrtouint(page, 0, &tmp);
272 static ssize_t nullb_device_ulong_attr_store(unsigned long *val,
273 const char *page, size_t count)
278 result = kstrtoul(page, 0, &tmp);
286 static ssize_t nullb_device_bool_attr_store(bool *val, const char *page,
292 result = kstrtobool(page, &tmp);
300 /* The following macro should only be used with TYPE = {uint, ulong, bool}. */
301 #define NULLB_DEVICE_ATTR(NAME, TYPE, APPLY) \
303 nullb_device_##NAME##_show(struct config_item *item, char *page) \
305 return nullb_device_##TYPE##_attr_show( \
306 to_nullb_device(item)->NAME, page); \
309 nullb_device_##NAME##_store(struct config_item *item, const char *page, \
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; \
317 ret = nullb_device_##TYPE##_attr_store(&new_value, page, count);\
321 ret = apply_fn(dev, new_value); \
322 else if (test_bit(NULLB_DEV_FL_CONFIGURED, &dev->flags)) \
326 dev->NAME = new_value; \
329 CONFIGFS_ATTR(nullb_device_, NAME);
331 static int nullb_apply_submit_queues(struct nullb_device *dev,
332 unsigned int submit_queues)
334 struct nullb *nullb = dev->nullb;
335 struct blk_mq_tag_set *set;
341 * Make sure that null_init_hctx() does not access nullb->queues[] past
342 * the end of that array.
344 if (submit_queues > nr_cpu_ids)
346 set = nullb->tag_set;
347 blk_mq_update_nr_hw_queues(set, submit_queues);
348 return set->nr_hw_queues == submit_queues ? 0 : -ENOMEM;
351 NULLB_DEVICE_ATTR(size, ulong, NULL);
352 NULLB_DEVICE_ATTR(completion_nsec, ulong, NULL);
353 NULLB_DEVICE_ATTR(submit_queues, uint, nullb_apply_submit_queues);
354 NULLB_DEVICE_ATTR(home_node, uint, NULL);
355 NULLB_DEVICE_ATTR(queue_mode, uint, NULL);
356 NULLB_DEVICE_ATTR(blocksize, uint, NULL);
357 NULLB_DEVICE_ATTR(max_sectors, uint, NULL);
358 NULLB_DEVICE_ATTR(irqmode, uint, NULL);
359 NULLB_DEVICE_ATTR(hw_queue_depth, uint, NULL);
360 NULLB_DEVICE_ATTR(index, uint, NULL);
361 NULLB_DEVICE_ATTR(blocking, bool, NULL);
362 NULLB_DEVICE_ATTR(use_per_node_hctx, bool, NULL);
363 NULLB_DEVICE_ATTR(memory_backed, bool, NULL);
364 NULLB_DEVICE_ATTR(discard, bool, NULL);
365 NULLB_DEVICE_ATTR(mbps, uint, NULL);
366 NULLB_DEVICE_ATTR(cache_size, ulong, NULL);
367 NULLB_DEVICE_ATTR(zoned, bool, NULL);
368 NULLB_DEVICE_ATTR(zone_size, ulong, NULL);
369 NULLB_DEVICE_ATTR(zone_capacity, ulong, NULL);
370 NULLB_DEVICE_ATTR(zone_nr_conv, uint, NULL);
371 NULLB_DEVICE_ATTR(zone_max_open, uint, NULL);
372 NULLB_DEVICE_ATTR(zone_max_active, uint, NULL);
373 NULLB_DEVICE_ATTR(virt_boundary, bool, NULL);
375 static ssize_t nullb_device_power_show(struct config_item *item, char *page)
377 return nullb_device_bool_attr_show(to_nullb_device(item)->power, page);
380 static ssize_t nullb_device_power_store(struct config_item *item,
381 const char *page, size_t count)
383 struct nullb_device *dev = to_nullb_device(item);
387 ret = nullb_device_bool_attr_store(&newp, page, count);
391 if (!dev->power && newp) {
392 if (test_and_set_bit(NULLB_DEV_FL_UP, &dev->flags))
394 if (null_add_dev(dev)) {
395 clear_bit(NULLB_DEV_FL_UP, &dev->flags);
399 set_bit(NULLB_DEV_FL_CONFIGURED, &dev->flags);
401 } else if (dev->power && !newp) {
402 if (test_and_clear_bit(NULLB_DEV_FL_UP, &dev->flags)) {
405 null_del_dev(dev->nullb);
408 clear_bit(NULLB_DEV_FL_CONFIGURED, &dev->flags);
414 CONFIGFS_ATTR(nullb_device_, power);
416 static ssize_t nullb_device_badblocks_show(struct config_item *item, char *page)
418 struct nullb_device *t_dev = to_nullb_device(item);
420 return badblocks_show(&t_dev->badblocks, page, 0);
423 static ssize_t nullb_device_badblocks_store(struct config_item *item,
424 const char *page, size_t count)
426 struct nullb_device *t_dev = to_nullb_device(item);
427 char *orig, *buf, *tmp;
431 orig = kstrndup(page, count, GFP_KERNEL);
435 buf = strstrip(orig);
438 if (buf[0] != '+' && buf[0] != '-')
440 tmp = strchr(&buf[1], '-');
444 ret = kstrtoull(buf + 1, 0, &start);
447 ret = kstrtoull(tmp + 1, 0, &end);
453 /* enable badblocks */
454 cmpxchg(&t_dev->badblocks.shift, -1, 0);
456 ret = badblocks_set(&t_dev->badblocks, start,
459 ret = badblocks_clear(&t_dev->badblocks, start,
467 CONFIGFS_ATTR(nullb_device_, badblocks);
469 static struct configfs_attribute *nullb_device_attrs[] = {
470 &nullb_device_attr_size,
471 &nullb_device_attr_completion_nsec,
472 &nullb_device_attr_submit_queues,
473 &nullb_device_attr_home_node,
474 &nullb_device_attr_queue_mode,
475 &nullb_device_attr_blocksize,
476 &nullb_device_attr_max_sectors,
477 &nullb_device_attr_irqmode,
478 &nullb_device_attr_hw_queue_depth,
479 &nullb_device_attr_index,
480 &nullb_device_attr_blocking,
481 &nullb_device_attr_use_per_node_hctx,
482 &nullb_device_attr_power,
483 &nullb_device_attr_memory_backed,
484 &nullb_device_attr_discard,
485 &nullb_device_attr_mbps,
486 &nullb_device_attr_cache_size,
487 &nullb_device_attr_badblocks,
488 &nullb_device_attr_zoned,
489 &nullb_device_attr_zone_size,
490 &nullb_device_attr_zone_capacity,
491 &nullb_device_attr_zone_nr_conv,
492 &nullb_device_attr_zone_max_open,
493 &nullb_device_attr_zone_max_active,
494 &nullb_device_attr_virt_boundary,
498 static void nullb_device_release(struct config_item *item)
500 struct nullb_device *dev = to_nullb_device(item);
502 null_free_device_storage(dev, false);
506 static struct configfs_item_operations nullb_device_ops = {
507 .release = nullb_device_release,
510 static const struct config_item_type nullb_device_type = {
511 .ct_item_ops = &nullb_device_ops,
512 .ct_attrs = nullb_device_attrs,
513 .ct_owner = THIS_MODULE,
517 config_item *nullb_group_make_item(struct config_group *group, const char *name)
519 struct nullb_device *dev;
521 dev = null_alloc_dev();
523 return ERR_PTR(-ENOMEM);
525 config_item_init_type_name(&dev->item, name, &nullb_device_type);
531 nullb_group_drop_item(struct config_group *group, struct config_item *item)
533 struct nullb_device *dev = to_nullb_device(item);
535 if (test_and_clear_bit(NULLB_DEV_FL_UP, &dev->flags)) {
538 null_del_dev(dev->nullb);
542 config_item_put(item);
545 static ssize_t memb_group_features_show(struct config_item *item, char *page)
547 return snprintf(page, PAGE_SIZE,
548 "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");
551 CONFIGFS_ATTR_RO(memb_group_, features);
553 static struct configfs_attribute *nullb_group_attrs[] = {
554 &memb_group_attr_features,
558 static struct configfs_group_operations nullb_group_ops = {
559 .make_item = nullb_group_make_item,
560 .drop_item = nullb_group_drop_item,
563 static const struct config_item_type nullb_group_type = {
564 .ct_group_ops = &nullb_group_ops,
565 .ct_attrs = nullb_group_attrs,
566 .ct_owner = THIS_MODULE,
569 static struct configfs_subsystem nullb_subsys = {
572 .ci_namebuf = "nullb",
573 .ci_type = &nullb_group_type,
578 static inline int null_cache_active(struct nullb *nullb)
580 return test_bit(NULLB_DEV_FL_CACHE, &nullb->dev->flags);
583 static struct nullb_device *null_alloc_dev(void)
585 struct nullb_device *dev;
587 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
590 INIT_RADIX_TREE(&dev->data, GFP_ATOMIC);
591 INIT_RADIX_TREE(&dev->cache, GFP_ATOMIC);
592 if (badblocks_init(&dev->badblocks, 0)) {
597 dev->size = g_gb * 1024;
598 dev->completion_nsec = g_completion_nsec;
599 dev->submit_queues = g_submit_queues;
600 dev->home_node = g_home_node;
601 dev->queue_mode = g_queue_mode;
602 dev->blocksize = g_bs;
603 dev->max_sectors = g_max_sectors;
604 dev->irqmode = g_irqmode;
605 dev->hw_queue_depth = g_hw_queue_depth;
606 dev->blocking = g_blocking;
607 dev->use_per_node_hctx = g_use_per_node_hctx;
608 dev->zoned = g_zoned;
609 dev->zone_size = g_zone_size;
610 dev->zone_capacity = g_zone_capacity;
611 dev->zone_nr_conv = g_zone_nr_conv;
612 dev->zone_max_open = g_zone_max_open;
613 dev->zone_max_active = g_zone_max_active;
614 dev->virt_boundary = g_virt_boundary;
618 static void null_free_dev(struct nullb_device *dev)
623 null_free_zoned_dev(dev);
624 badblocks_exit(&dev->badblocks);
628 static void put_tag(struct nullb_queue *nq, unsigned int tag)
630 clear_bit_unlock(tag, nq->tag_map);
632 if (waitqueue_active(&nq->wait))
636 static unsigned int get_tag(struct nullb_queue *nq)
641 tag = find_first_zero_bit(nq->tag_map, nq->queue_depth);
642 if (tag >= nq->queue_depth)
644 } while (test_and_set_bit_lock(tag, nq->tag_map));
649 static void free_cmd(struct nullb_cmd *cmd)
651 put_tag(cmd->nq, cmd->tag);
654 static enum hrtimer_restart null_cmd_timer_expired(struct hrtimer *timer);
656 static struct nullb_cmd *__alloc_cmd(struct nullb_queue *nq)
658 struct nullb_cmd *cmd;
663 cmd = &nq->cmds[tag];
665 cmd->error = BLK_STS_OK;
667 if (nq->dev->irqmode == NULL_IRQ_TIMER) {
668 hrtimer_init(&cmd->timer, CLOCK_MONOTONIC,
670 cmd->timer.function = null_cmd_timer_expired;
678 static struct nullb_cmd *alloc_cmd(struct nullb_queue *nq, int can_wait)
680 struct nullb_cmd *cmd;
683 cmd = __alloc_cmd(nq);
684 if (cmd || !can_wait)
688 prepare_to_wait(&nq->wait, &wait, TASK_UNINTERRUPTIBLE);
689 cmd = __alloc_cmd(nq);
696 finish_wait(&nq->wait, &wait);
700 static void end_cmd(struct nullb_cmd *cmd)
702 int queue_mode = cmd->nq->dev->queue_mode;
704 switch (queue_mode) {
706 blk_mq_end_request(cmd->rq, cmd->error);
709 cmd->bio->bi_status = cmd->error;
717 static enum hrtimer_restart null_cmd_timer_expired(struct hrtimer *timer)
719 end_cmd(container_of(timer, struct nullb_cmd, timer));
721 return HRTIMER_NORESTART;
724 static void null_cmd_end_timer(struct nullb_cmd *cmd)
726 ktime_t kt = cmd->nq->dev->completion_nsec;
728 hrtimer_start(&cmd->timer, kt, HRTIMER_MODE_REL);
731 static void null_complete_rq(struct request *rq)
733 end_cmd(blk_mq_rq_to_pdu(rq));
736 static struct nullb_page *null_alloc_page(gfp_t gfp_flags)
738 struct nullb_page *t_page;
740 t_page = kmalloc(sizeof(struct nullb_page), gfp_flags);
744 t_page->page = alloc_pages(gfp_flags, 0);
748 memset(t_page->bitmap, 0, sizeof(t_page->bitmap));
756 static void null_free_page(struct nullb_page *t_page)
758 __set_bit(NULLB_PAGE_FREE, t_page->bitmap);
759 if (test_bit(NULLB_PAGE_LOCK, t_page->bitmap))
761 __free_page(t_page->page);
765 static bool null_page_empty(struct nullb_page *page)
767 int size = MAP_SZ - 2;
769 return find_first_bit(page->bitmap, size) == size;
772 static void null_free_sector(struct nullb *nullb, sector_t sector,
775 unsigned int sector_bit;
777 struct nullb_page *t_page, *ret;
778 struct radix_tree_root *root;
780 root = is_cache ? &nullb->dev->cache : &nullb->dev->data;
781 idx = sector >> PAGE_SECTORS_SHIFT;
782 sector_bit = (sector & SECTOR_MASK);
784 t_page = radix_tree_lookup(root, idx);
786 __clear_bit(sector_bit, t_page->bitmap);
788 if (null_page_empty(t_page)) {
789 ret = radix_tree_delete_item(root, idx, t_page);
790 WARN_ON(ret != t_page);
793 nullb->dev->curr_cache -= PAGE_SIZE;
798 static struct nullb_page *null_radix_tree_insert(struct nullb *nullb, u64 idx,
799 struct nullb_page *t_page, bool is_cache)
801 struct radix_tree_root *root;
803 root = is_cache ? &nullb->dev->cache : &nullb->dev->data;
805 if (radix_tree_insert(root, idx, t_page)) {
806 null_free_page(t_page);
807 t_page = radix_tree_lookup(root, idx);
808 WARN_ON(!t_page || t_page->page->index != idx);
810 nullb->dev->curr_cache += PAGE_SIZE;
815 static void null_free_device_storage(struct nullb_device *dev, bool is_cache)
817 unsigned long pos = 0;
819 struct nullb_page *ret, *t_pages[FREE_BATCH];
820 struct radix_tree_root *root;
822 root = is_cache ? &dev->cache : &dev->data;
827 nr_pages = radix_tree_gang_lookup(root,
828 (void **)t_pages, pos, FREE_BATCH);
830 for (i = 0; i < nr_pages; i++) {
831 pos = t_pages[i]->page->index;
832 ret = radix_tree_delete_item(root, pos, t_pages[i]);
833 WARN_ON(ret != t_pages[i]);
838 } while (nr_pages == FREE_BATCH);
844 static struct nullb_page *__null_lookup_page(struct nullb *nullb,
845 sector_t sector, bool for_write, bool is_cache)
847 unsigned int sector_bit;
849 struct nullb_page *t_page;
850 struct radix_tree_root *root;
852 idx = sector >> PAGE_SECTORS_SHIFT;
853 sector_bit = (sector & SECTOR_MASK);
855 root = is_cache ? &nullb->dev->cache : &nullb->dev->data;
856 t_page = radix_tree_lookup(root, idx);
857 WARN_ON(t_page && t_page->page->index != idx);
859 if (t_page && (for_write || test_bit(sector_bit, t_page->bitmap)))
865 static struct nullb_page *null_lookup_page(struct nullb *nullb,
866 sector_t sector, bool for_write, bool ignore_cache)
868 struct nullb_page *page = NULL;
871 page = __null_lookup_page(nullb, sector, for_write, true);
874 return __null_lookup_page(nullb, sector, for_write, false);
877 static struct nullb_page *null_insert_page(struct nullb *nullb,
878 sector_t sector, bool ignore_cache)
879 __releases(&nullb->lock)
880 __acquires(&nullb->lock)
883 struct nullb_page *t_page;
885 t_page = null_lookup_page(nullb, sector, true, ignore_cache);
889 spin_unlock_irq(&nullb->lock);
891 t_page = null_alloc_page(GFP_NOIO);
895 if (radix_tree_preload(GFP_NOIO))
898 spin_lock_irq(&nullb->lock);
899 idx = sector >> PAGE_SECTORS_SHIFT;
900 t_page->page->index = idx;
901 t_page = null_radix_tree_insert(nullb, idx, t_page, !ignore_cache);
902 radix_tree_preload_end();
906 null_free_page(t_page);
908 spin_lock_irq(&nullb->lock);
909 return null_lookup_page(nullb, sector, true, ignore_cache);
912 static int null_flush_cache_page(struct nullb *nullb, struct nullb_page *c_page)
917 struct nullb_page *t_page, *ret;
920 idx = c_page->page->index;
922 t_page = null_insert_page(nullb, idx << PAGE_SECTORS_SHIFT, true);
924 __clear_bit(NULLB_PAGE_LOCK, c_page->bitmap);
925 if (test_bit(NULLB_PAGE_FREE, c_page->bitmap)) {
926 null_free_page(c_page);
927 if (t_page && null_page_empty(t_page)) {
928 ret = radix_tree_delete_item(&nullb->dev->data,
930 null_free_page(t_page);
938 src = kmap_atomic(c_page->page);
939 dst = kmap_atomic(t_page->page);
941 for (i = 0; i < PAGE_SECTORS;
942 i += (nullb->dev->blocksize >> SECTOR_SHIFT)) {
943 if (test_bit(i, c_page->bitmap)) {
944 offset = (i << SECTOR_SHIFT);
945 memcpy(dst + offset, src + offset,
946 nullb->dev->blocksize);
947 __set_bit(i, t_page->bitmap);
954 ret = radix_tree_delete_item(&nullb->dev->cache, idx, c_page);
956 nullb->dev->curr_cache -= PAGE_SIZE;
961 static int null_make_cache_space(struct nullb *nullb, unsigned long n)
963 int i, err, nr_pages;
964 struct nullb_page *c_pages[FREE_BATCH];
965 unsigned long flushed = 0, one_round;
968 if ((nullb->dev->cache_size * 1024 * 1024) >
969 nullb->dev->curr_cache + n || nullb->dev->curr_cache == 0)
972 nr_pages = radix_tree_gang_lookup(&nullb->dev->cache,
973 (void **)c_pages, nullb->cache_flush_pos, FREE_BATCH);
975 * nullb_flush_cache_page could unlock before using the c_pages. To
976 * avoid race, we don't allow page free
978 for (i = 0; i < nr_pages; i++) {
979 nullb->cache_flush_pos = c_pages[i]->page->index;
981 * We found the page which is being flushed to disk by other
984 if (test_bit(NULLB_PAGE_LOCK, c_pages[i]->bitmap))
987 __set_bit(NULLB_PAGE_LOCK, c_pages[i]->bitmap);
991 for (i = 0; i < nr_pages; i++) {
992 if (c_pages[i] == NULL)
994 err = null_flush_cache_page(nullb, c_pages[i]);
999 flushed += one_round << PAGE_SHIFT;
1003 nullb->cache_flush_pos = 0;
1004 if (one_round == 0) {
1005 /* give other threads a chance */
1006 spin_unlock_irq(&nullb->lock);
1007 spin_lock_irq(&nullb->lock);
1014 static int copy_to_nullb(struct nullb *nullb, struct page *source,
1015 unsigned int off, sector_t sector, size_t n, bool is_fua)
1017 size_t temp, count = 0;
1018 unsigned int offset;
1019 struct nullb_page *t_page;
1023 temp = min_t(size_t, nullb->dev->blocksize, n - count);
1025 if (null_cache_active(nullb) && !is_fua)
1026 null_make_cache_space(nullb, PAGE_SIZE);
1028 offset = (sector & SECTOR_MASK) << SECTOR_SHIFT;
1029 t_page = null_insert_page(nullb, sector,
1030 !null_cache_active(nullb) || is_fua);
1034 src = kmap_atomic(source);
1035 dst = kmap_atomic(t_page->page);
1036 memcpy(dst + offset, src + off + count, temp);
1040 __set_bit(sector & SECTOR_MASK, t_page->bitmap);
1043 null_free_sector(nullb, sector, true);
1046 sector += temp >> SECTOR_SHIFT;
1051 static int copy_from_nullb(struct nullb *nullb, struct page *dest,
1052 unsigned int off, sector_t sector, size_t n)
1054 size_t temp, count = 0;
1055 unsigned int offset;
1056 struct nullb_page *t_page;
1060 temp = min_t(size_t, nullb->dev->blocksize, n - count);
1062 offset = (sector & SECTOR_MASK) << SECTOR_SHIFT;
1063 t_page = null_lookup_page(nullb, sector, false,
1064 !null_cache_active(nullb));
1066 dst = kmap_atomic(dest);
1068 memset(dst + off + count, 0, temp);
1071 src = kmap_atomic(t_page->page);
1072 memcpy(dst + off + count, src + offset, temp);
1078 sector += temp >> SECTOR_SHIFT;
1083 static void nullb_fill_pattern(struct nullb *nullb, struct page *page,
1084 unsigned int len, unsigned int off)
1088 dst = kmap_atomic(page);
1089 memset(dst + off, 0xFF, len);
1093 blk_status_t null_handle_discard(struct nullb_device *dev,
1094 sector_t sector, sector_t nr_sectors)
1096 struct nullb *nullb = dev->nullb;
1097 size_t n = nr_sectors << SECTOR_SHIFT;
1100 spin_lock_irq(&nullb->lock);
1102 temp = min_t(size_t, n, dev->blocksize);
1103 null_free_sector(nullb, sector, false);
1104 if (null_cache_active(nullb))
1105 null_free_sector(nullb, sector, true);
1106 sector += temp >> SECTOR_SHIFT;
1109 spin_unlock_irq(&nullb->lock);
1114 static int null_handle_flush(struct nullb *nullb)
1118 if (!null_cache_active(nullb))
1121 spin_lock_irq(&nullb->lock);
1123 err = null_make_cache_space(nullb,
1124 nullb->dev->cache_size * 1024 * 1024);
1125 if (err || nullb->dev->curr_cache == 0)
1129 WARN_ON(!radix_tree_empty(&nullb->dev->cache));
1130 spin_unlock_irq(&nullb->lock);
1134 static int null_transfer(struct nullb *nullb, struct page *page,
1135 unsigned int len, unsigned int off, bool is_write, sector_t sector,
1138 struct nullb_device *dev = nullb->dev;
1139 unsigned int valid_len = len;
1144 valid_len = null_zone_valid_read_len(nullb,
1148 err = copy_from_nullb(nullb, page, off,
1155 nullb_fill_pattern(nullb, page, len, off);
1156 flush_dcache_page(page);
1158 flush_dcache_page(page);
1159 err = copy_to_nullb(nullb, page, off, sector, len, is_fua);
1165 static int null_handle_rq(struct nullb_cmd *cmd)
1167 struct request *rq = cmd->rq;
1168 struct nullb *nullb = cmd->nq->dev->nullb;
1171 sector_t sector = blk_rq_pos(rq);
1172 struct req_iterator iter;
1173 struct bio_vec bvec;
1175 spin_lock_irq(&nullb->lock);
1176 rq_for_each_segment(bvec, rq, iter) {
1178 err = null_transfer(nullb, bvec.bv_page, len, bvec.bv_offset,
1179 op_is_write(req_op(rq)), sector,
1180 rq->cmd_flags & REQ_FUA);
1182 spin_unlock_irq(&nullb->lock);
1185 sector += len >> SECTOR_SHIFT;
1187 spin_unlock_irq(&nullb->lock);
1192 static int null_handle_bio(struct nullb_cmd *cmd)
1194 struct bio *bio = cmd->bio;
1195 struct nullb *nullb = cmd->nq->dev->nullb;
1198 sector_t sector = bio->bi_iter.bi_sector;
1199 struct bio_vec bvec;
1200 struct bvec_iter iter;
1202 spin_lock_irq(&nullb->lock);
1203 bio_for_each_segment(bvec, bio, iter) {
1205 err = null_transfer(nullb, bvec.bv_page, len, bvec.bv_offset,
1206 op_is_write(bio_op(bio)), sector,
1207 bio->bi_opf & REQ_FUA);
1209 spin_unlock_irq(&nullb->lock);
1212 sector += len >> SECTOR_SHIFT;
1214 spin_unlock_irq(&nullb->lock);
1218 static void null_stop_queue(struct nullb *nullb)
1220 struct request_queue *q = nullb->q;
1222 if (nullb->dev->queue_mode == NULL_Q_MQ)
1223 blk_mq_stop_hw_queues(q);
1226 static void null_restart_queue_async(struct nullb *nullb)
1228 struct request_queue *q = nullb->q;
1230 if (nullb->dev->queue_mode == NULL_Q_MQ)
1231 blk_mq_start_stopped_hw_queues(q, true);
1234 static inline blk_status_t null_handle_throttled(struct nullb_cmd *cmd)
1236 struct nullb_device *dev = cmd->nq->dev;
1237 struct nullb *nullb = dev->nullb;
1238 blk_status_t sts = BLK_STS_OK;
1239 struct request *rq = cmd->rq;
1241 if (!hrtimer_active(&nullb->bw_timer))
1242 hrtimer_restart(&nullb->bw_timer);
1244 if (atomic_long_sub_return(blk_rq_bytes(rq), &nullb->cur_bytes) < 0) {
1245 null_stop_queue(nullb);
1246 /* race with timer */
1247 if (atomic_long_read(&nullb->cur_bytes) > 0)
1248 null_restart_queue_async(nullb);
1249 /* requeue request */
1250 sts = BLK_STS_DEV_RESOURCE;
1255 static inline blk_status_t null_handle_badblocks(struct nullb_cmd *cmd,
1257 sector_t nr_sectors)
1259 struct badblocks *bb = &cmd->nq->dev->badblocks;
1263 if (badblocks_check(bb, sector, nr_sectors, &first_bad, &bad_sectors))
1264 return BLK_STS_IOERR;
1269 static inline blk_status_t null_handle_memory_backed(struct nullb_cmd *cmd,
1272 sector_t nr_sectors)
1274 struct nullb_device *dev = cmd->nq->dev;
1277 if (op == REQ_OP_DISCARD)
1278 return null_handle_discard(dev, sector, nr_sectors);
1280 if (dev->queue_mode == NULL_Q_BIO)
1281 err = null_handle_bio(cmd);
1283 err = null_handle_rq(cmd);
1285 return errno_to_blk_status(err);
1288 static void nullb_zero_read_cmd_buffer(struct nullb_cmd *cmd)
1290 struct nullb_device *dev = cmd->nq->dev;
1293 if (dev->memory_backed)
1296 if (dev->queue_mode == NULL_Q_BIO && bio_op(cmd->bio) == REQ_OP_READ) {
1297 zero_fill_bio(cmd->bio);
1298 } else if (req_op(cmd->rq) == REQ_OP_READ) {
1299 __rq_for_each_bio(bio, cmd->rq)
1304 static inline void nullb_complete_cmd(struct nullb_cmd *cmd)
1307 * Since root privileges are required to configure the null_blk
1308 * driver, it is fine that this driver does not initialize the
1309 * data buffers of read commands. Zero-initialize these buffers
1310 * anyway if KMSAN is enabled to prevent that KMSAN complains
1311 * about null_blk not initializing read data buffers.
1313 if (IS_ENABLED(CONFIG_KMSAN))
1314 nullb_zero_read_cmd_buffer(cmd);
1316 /* Complete IO by inline, softirq or timer */
1317 switch (cmd->nq->dev->irqmode) {
1318 case NULL_IRQ_SOFTIRQ:
1319 switch (cmd->nq->dev->queue_mode) {
1321 if (likely(!blk_should_fake_timeout(cmd->rq->q)))
1322 blk_mq_complete_request(cmd->rq);
1326 * XXX: no proper submitting cpu information available.
1335 case NULL_IRQ_TIMER:
1336 null_cmd_end_timer(cmd);
1341 blk_status_t null_process_cmd(struct nullb_cmd *cmd,
1342 enum req_opf op, sector_t sector,
1343 unsigned int nr_sectors)
1345 struct nullb_device *dev = cmd->nq->dev;
1348 if (dev->badblocks.shift != -1) {
1349 ret = null_handle_badblocks(cmd, sector, nr_sectors);
1350 if (ret != BLK_STS_OK)
1354 if (dev->memory_backed)
1355 return null_handle_memory_backed(cmd, op, sector, nr_sectors);
1360 static blk_status_t null_handle_cmd(struct nullb_cmd *cmd, sector_t sector,
1361 sector_t nr_sectors, enum req_opf op)
1363 struct nullb_device *dev = cmd->nq->dev;
1364 struct nullb *nullb = dev->nullb;
1367 if (test_bit(NULLB_DEV_FL_THROTTLED, &dev->flags)) {
1368 sts = null_handle_throttled(cmd);
1369 if (sts != BLK_STS_OK)
1373 if (op == REQ_OP_FLUSH) {
1374 cmd->error = errno_to_blk_status(null_handle_flush(nullb));
1379 sts = null_process_zoned_cmd(cmd, op, sector, nr_sectors);
1381 sts = null_process_cmd(cmd, op, sector, nr_sectors);
1383 /* Do not overwrite errors (e.g. timeout errors) */
1384 if (cmd->error == BLK_STS_OK)
1388 nullb_complete_cmd(cmd);
1392 static enum hrtimer_restart nullb_bwtimer_fn(struct hrtimer *timer)
1394 struct nullb *nullb = container_of(timer, struct nullb, bw_timer);
1395 ktime_t timer_interval = ktime_set(0, TIMER_INTERVAL);
1396 unsigned int mbps = nullb->dev->mbps;
1398 if (atomic_long_read(&nullb->cur_bytes) == mb_per_tick(mbps))
1399 return HRTIMER_NORESTART;
1401 atomic_long_set(&nullb->cur_bytes, mb_per_tick(mbps));
1402 null_restart_queue_async(nullb);
1404 hrtimer_forward_now(&nullb->bw_timer, timer_interval);
1406 return HRTIMER_RESTART;
1409 static void nullb_setup_bwtimer(struct nullb *nullb)
1411 ktime_t timer_interval = ktime_set(0, TIMER_INTERVAL);
1413 hrtimer_init(&nullb->bw_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
1414 nullb->bw_timer.function = nullb_bwtimer_fn;
1415 atomic_long_set(&nullb->cur_bytes, mb_per_tick(nullb->dev->mbps));
1416 hrtimer_start(&nullb->bw_timer, timer_interval, HRTIMER_MODE_REL);
1419 static struct nullb_queue *nullb_to_queue(struct nullb *nullb)
1423 if (nullb->nr_queues != 1)
1424 index = raw_smp_processor_id() / ((nr_cpu_ids + nullb->nr_queues - 1) / nullb->nr_queues);
1426 return &nullb->queues[index];
1429 static blk_qc_t null_submit_bio(struct bio *bio)
1431 sector_t sector = bio->bi_iter.bi_sector;
1432 sector_t nr_sectors = bio_sectors(bio);
1433 struct nullb *nullb = bio->bi_bdev->bd_disk->private_data;
1434 struct nullb_queue *nq = nullb_to_queue(nullb);
1435 struct nullb_cmd *cmd;
1437 cmd = alloc_cmd(nq, 1);
1440 null_handle_cmd(cmd, sector, nr_sectors, bio_op(bio));
1441 return BLK_QC_T_NONE;
1444 static bool should_timeout_request(struct request *rq)
1446 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
1447 if (g_timeout_str[0])
1448 return should_fail(&null_timeout_attr, 1);
1453 static bool should_requeue_request(struct request *rq)
1455 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
1456 if (g_requeue_str[0])
1457 return should_fail(&null_requeue_attr, 1);
1462 static enum blk_eh_timer_return null_timeout_rq(struct request *rq, bool res)
1464 struct nullb_cmd *cmd = blk_mq_rq_to_pdu(rq);
1466 pr_info("rq %p timed out\n", rq);
1469 * If the device is marked as blocking (i.e. memory backed or zoned
1470 * device), the submission path may be blocked waiting for resources
1471 * and cause real timeouts. For these real timeouts, the submission
1472 * path will complete the request using blk_mq_complete_request().
1473 * Only fake timeouts need to execute blk_mq_complete_request() here.
1475 cmd->error = BLK_STS_TIMEOUT;
1476 if (cmd->fake_timeout)
1477 blk_mq_complete_request(rq);
1481 static blk_status_t null_queue_rq(struct blk_mq_hw_ctx *hctx,
1482 const struct blk_mq_queue_data *bd)
1484 struct nullb_cmd *cmd = blk_mq_rq_to_pdu(bd->rq);
1485 struct nullb_queue *nq = hctx->driver_data;
1486 sector_t nr_sectors = blk_rq_sectors(bd->rq);
1487 sector_t sector = blk_rq_pos(bd->rq);
1489 might_sleep_if(hctx->flags & BLK_MQ_F_BLOCKING);
1491 if (nq->dev->irqmode == NULL_IRQ_TIMER) {
1492 hrtimer_init(&cmd->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
1493 cmd->timer.function = null_cmd_timer_expired;
1496 cmd->error = BLK_STS_OK;
1498 cmd->fake_timeout = should_timeout_request(bd->rq);
1500 blk_mq_start_request(bd->rq);
1502 if (should_requeue_request(bd->rq)) {
1504 * Alternate between hitting the core BUSY path, and the
1505 * driver driven requeue path
1507 nq->requeue_selection++;
1508 if (nq->requeue_selection & 1)
1509 return BLK_STS_RESOURCE;
1511 blk_mq_requeue_request(bd->rq, true);
1515 if (cmd->fake_timeout)
1518 return null_handle_cmd(cmd, sector, nr_sectors, req_op(bd->rq));
1521 static void cleanup_queue(struct nullb_queue *nq)
1527 static void cleanup_queues(struct nullb *nullb)
1531 for (i = 0; i < nullb->nr_queues; i++)
1532 cleanup_queue(&nullb->queues[i]);
1534 kfree(nullb->queues);
1537 static void null_exit_hctx(struct blk_mq_hw_ctx *hctx, unsigned int hctx_idx)
1539 struct nullb_queue *nq = hctx->driver_data;
1540 struct nullb *nullb = nq->dev->nullb;
1545 static void null_init_queue(struct nullb *nullb, struct nullb_queue *nq)
1547 init_waitqueue_head(&nq->wait);
1548 nq->queue_depth = nullb->queue_depth;
1549 nq->dev = nullb->dev;
1552 static int null_init_hctx(struct blk_mq_hw_ctx *hctx, void *driver_data,
1553 unsigned int hctx_idx)
1555 struct nullb *nullb = hctx->queue->queuedata;
1556 struct nullb_queue *nq;
1558 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
1559 if (g_init_hctx_str[0] && should_fail(&null_init_hctx_attr, 1))
1563 nq = &nullb->queues[hctx_idx];
1564 hctx->driver_data = nq;
1565 null_init_queue(nullb, nq);
1571 static const struct blk_mq_ops null_mq_ops = {
1572 .queue_rq = null_queue_rq,
1573 .complete = null_complete_rq,
1574 .timeout = null_timeout_rq,
1575 .init_hctx = null_init_hctx,
1576 .exit_hctx = null_exit_hctx,
1579 static void null_del_dev(struct nullb *nullb)
1581 struct nullb_device *dev;
1588 ida_simple_remove(&nullb_indexes, nullb->index);
1590 list_del_init(&nullb->list);
1592 del_gendisk(nullb->disk);
1594 if (test_bit(NULLB_DEV_FL_THROTTLED, &nullb->dev->flags)) {
1595 hrtimer_cancel(&nullb->bw_timer);
1596 atomic_long_set(&nullb->cur_bytes, LONG_MAX);
1597 null_restart_queue_async(nullb);
1600 blk_cleanup_disk(nullb->disk);
1601 if (dev->queue_mode == NULL_Q_MQ &&
1602 nullb->tag_set == &nullb->__tag_set)
1603 blk_mq_free_tag_set(nullb->tag_set);
1604 cleanup_queues(nullb);
1605 if (null_cache_active(nullb))
1606 null_free_device_storage(nullb->dev, true);
1611 static void null_config_discard(struct nullb *nullb)
1613 if (nullb->dev->discard == false)
1616 if (!nullb->dev->memory_backed) {
1617 nullb->dev->discard = false;
1618 pr_info("discard option is ignored without memory backing\n");
1622 if (nullb->dev->zoned) {
1623 nullb->dev->discard = false;
1624 pr_info("discard option is ignored in zoned mode\n");
1628 nullb->q->limits.discard_granularity = nullb->dev->blocksize;
1629 nullb->q->limits.discard_alignment = nullb->dev->blocksize;
1630 blk_queue_max_discard_sectors(nullb->q, UINT_MAX >> 9);
1631 blk_queue_flag_set(QUEUE_FLAG_DISCARD, nullb->q);
1634 static const struct block_device_operations null_bio_ops = {
1635 .owner = THIS_MODULE,
1636 .submit_bio = null_submit_bio,
1637 .report_zones = null_report_zones,
1640 static const struct block_device_operations null_rq_ops = {
1641 .owner = THIS_MODULE,
1642 .report_zones = null_report_zones,
1645 static int setup_commands(struct nullb_queue *nq)
1647 struct nullb_cmd *cmd;
1650 nq->cmds = kcalloc(nq->queue_depth, sizeof(*cmd), GFP_KERNEL);
1654 tag_size = ALIGN(nq->queue_depth, BITS_PER_LONG) / BITS_PER_LONG;
1655 nq->tag_map = kcalloc(tag_size, sizeof(unsigned long), GFP_KERNEL);
1661 for (i = 0; i < nq->queue_depth; i++) {
1669 static int setup_queues(struct nullb *nullb)
1671 nullb->queues = kcalloc(nr_cpu_ids, sizeof(struct nullb_queue),
1676 nullb->queue_depth = nullb->dev->hw_queue_depth;
1681 static int init_driver_queues(struct nullb *nullb)
1683 struct nullb_queue *nq;
1686 for (i = 0; i < nullb->dev->submit_queues; i++) {
1687 nq = &nullb->queues[i];
1689 null_init_queue(nullb, nq);
1691 ret = setup_commands(nq);
1699 static int null_gendisk_register(struct nullb *nullb)
1701 sector_t size = ((sector_t)nullb->dev->size * SZ_1M) >> SECTOR_SHIFT;
1702 struct gendisk *disk = nullb->disk;
1704 set_capacity(disk, size);
1706 disk->flags |= GENHD_FL_EXT_DEVT | GENHD_FL_SUPPRESS_PARTITION_INFO;
1707 disk->major = null_major;
1708 disk->first_minor = nullb->index;
1710 if (queue_is_mq(nullb->q))
1711 disk->fops = &null_rq_ops;
1713 disk->fops = &null_bio_ops;
1714 disk->private_data = nullb;
1715 strncpy(disk->disk_name, nullb->disk_name, DISK_NAME_LEN);
1717 if (nullb->dev->zoned) {
1718 int ret = null_register_zoned_dev(nullb);
1728 static int null_init_tag_set(struct nullb *nullb, struct blk_mq_tag_set *set)
1730 set->ops = &null_mq_ops;
1731 set->nr_hw_queues = nullb ? nullb->dev->submit_queues :
1733 set->queue_depth = nullb ? nullb->dev->hw_queue_depth :
1735 set->numa_node = nullb ? nullb->dev->home_node : g_home_node;
1736 set->cmd_size = sizeof(struct nullb_cmd);
1737 set->flags = BLK_MQ_F_SHOULD_MERGE;
1739 set->flags |= BLK_MQ_F_NO_SCHED;
1740 if (g_shared_tag_bitmap)
1741 set->flags |= BLK_MQ_F_TAG_HCTX_SHARED;
1742 set->driver_data = NULL;
1744 if ((nullb && nullb->dev->blocking) || g_blocking)
1745 set->flags |= BLK_MQ_F_BLOCKING;
1747 return blk_mq_alloc_tag_set(set);
1750 static int null_validate_conf(struct nullb_device *dev)
1752 dev->blocksize = round_down(dev->blocksize, 512);
1753 dev->blocksize = clamp_t(unsigned int, dev->blocksize, 512, 4096);
1755 if (dev->queue_mode == NULL_Q_MQ && dev->use_per_node_hctx) {
1756 if (dev->submit_queues != nr_online_nodes)
1757 dev->submit_queues = nr_online_nodes;
1758 } else if (dev->submit_queues > nr_cpu_ids)
1759 dev->submit_queues = nr_cpu_ids;
1760 else if (dev->submit_queues == 0)
1761 dev->submit_queues = 1;
1763 dev->queue_mode = min_t(unsigned int, dev->queue_mode, NULL_Q_MQ);
1764 dev->irqmode = min_t(unsigned int, dev->irqmode, NULL_IRQ_TIMER);
1766 /* Do memory allocation, so set blocking */
1767 if (dev->memory_backed)
1768 dev->blocking = true;
1769 else /* cache is meaningless */
1770 dev->cache_size = 0;
1771 dev->cache_size = min_t(unsigned long, ULONG_MAX / 1024 / 1024,
1773 dev->mbps = min_t(unsigned int, 1024 * 40, dev->mbps);
1774 /* can not stop a queue */
1775 if (dev->queue_mode == NULL_Q_BIO)
1779 (!dev->zone_size || !is_power_of_2(dev->zone_size))) {
1780 pr_err("zone_size must be power-of-two\n");
1787 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
1788 static bool __null_setup_fault(struct fault_attr *attr, char *str)
1793 if (!setup_fault_attr(attr, str))
1801 static bool null_setup_fault(void)
1803 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
1804 if (!__null_setup_fault(&null_timeout_attr, g_timeout_str))
1806 if (!__null_setup_fault(&null_requeue_attr, g_requeue_str))
1808 if (!__null_setup_fault(&null_init_hctx_attr, g_init_hctx_str))
1814 static int null_add_dev(struct nullb_device *dev)
1816 struct nullb *nullb;
1819 rv = null_validate_conf(dev);
1823 nullb = kzalloc_node(sizeof(*nullb), GFP_KERNEL, dev->home_node);
1831 spin_lock_init(&nullb->lock);
1833 rv = setup_queues(nullb);
1835 goto out_free_nullb;
1837 if (dev->queue_mode == NULL_Q_MQ) {
1839 nullb->tag_set = &tag_set;
1842 nullb->tag_set = &nullb->__tag_set;
1843 rv = null_init_tag_set(nullb, nullb->tag_set);
1847 goto out_cleanup_queues;
1849 if (!null_setup_fault())
1850 goto out_cleanup_tags;
1853 nullb->tag_set->timeout = 5 * HZ;
1854 nullb->disk = blk_mq_alloc_disk(nullb->tag_set, nullb);
1855 if (IS_ERR(nullb->disk)) {
1856 rv = PTR_ERR(nullb->disk);
1857 goto out_cleanup_tags;
1859 nullb->q = nullb->disk->queue;
1860 } else if (dev->queue_mode == NULL_Q_BIO) {
1862 nullb->disk = blk_alloc_disk(nullb->dev->home_node);
1864 goto out_cleanup_queues;
1866 nullb->q = nullb->disk->queue;
1867 rv = init_driver_queues(nullb);
1869 goto out_cleanup_disk;
1873 set_bit(NULLB_DEV_FL_THROTTLED, &dev->flags);
1874 nullb_setup_bwtimer(nullb);
1877 if (dev->cache_size > 0) {
1878 set_bit(NULLB_DEV_FL_CACHE, &nullb->dev->flags);
1879 blk_queue_write_cache(nullb->q, true, true);
1883 rv = null_init_zoned_dev(dev, nullb->q);
1885 goto out_cleanup_disk;
1888 nullb->q->queuedata = nullb;
1889 blk_queue_flag_set(QUEUE_FLAG_NONROT, nullb->q);
1890 blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, nullb->q);
1893 nullb->index = ida_simple_get(&nullb_indexes, 0, 0, GFP_KERNEL);
1894 dev->index = nullb->index;
1895 mutex_unlock(&lock);
1897 blk_queue_logical_block_size(nullb->q, dev->blocksize);
1898 blk_queue_physical_block_size(nullb->q, dev->blocksize);
1899 if (!dev->max_sectors)
1900 dev->max_sectors = queue_max_hw_sectors(nullb->q);
1901 dev->max_sectors = min_t(unsigned int, dev->max_sectors,
1902 BLK_DEF_MAX_SECTORS);
1903 blk_queue_max_hw_sectors(nullb->q, dev->max_sectors);
1905 if (dev->virt_boundary)
1906 blk_queue_virt_boundary(nullb->q, PAGE_SIZE - 1);
1908 null_config_discard(nullb);
1910 sprintf(nullb->disk_name, "nullb%d", nullb->index);
1912 rv = null_gendisk_register(nullb);
1914 goto out_cleanup_zone;
1917 list_add_tail(&nullb->list, &nullb_list);
1918 mutex_unlock(&lock);
1922 null_free_zoned_dev(dev);
1924 blk_cleanup_disk(nullb->disk);
1926 if (dev->queue_mode == NULL_Q_MQ && nullb->tag_set == &nullb->__tag_set)
1927 blk_mq_free_tag_set(nullb->tag_set);
1929 cleanup_queues(nullb);
1937 static int __init null_init(void)
1941 struct nullb *nullb;
1942 struct nullb_device *dev;
1944 if (g_bs > PAGE_SIZE) {
1945 pr_warn("invalid block size\n");
1946 pr_warn("defaults block size to %lu\n", PAGE_SIZE);
1950 if (g_max_sectors > BLK_DEF_MAX_SECTORS) {
1951 pr_warn("invalid max sectors\n");
1952 pr_warn("defaults max sectors to %u\n", BLK_DEF_MAX_SECTORS);
1953 g_max_sectors = BLK_DEF_MAX_SECTORS;
1956 if (g_home_node != NUMA_NO_NODE && g_home_node >= nr_online_nodes) {
1957 pr_err("invalid home_node value\n");
1958 g_home_node = NUMA_NO_NODE;
1961 if (g_queue_mode == NULL_Q_RQ) {
1962 pr_err("legacy IO path no longer available\n");
1965 if (g_queue_mode == NULL_Q_MQ && g_use_per_node_hctx) {
1966 if (g_submit_queues != nr_online_nodes) {
1967 pr_warn("submit_queues param is set to %u.\n",
1969 g_submit_queues = nr_online_nodes;
1971 } else if (g_submit_queues > nr_cpu_ids)
1972 g_submit_queues = nr_cpu_ids;
1973 else if (g_submit_queues <= 0)
1974 g_submit_queues = 1;
1976 if (g_queue_mode == NULL_Q_MQ && shared_tags) {
1977 ret = null_init_tag_set(NULL, &tag_set);
1982 config_group_init(&nullb_subsys.su_group);
1983 mutex_init(&nullb_subsys.su_mutex);
1985 ret = configfs_register_subsystem(&nullb_subsys);
1991 null_major = register_blkdev(0, "nullb");
1992 if (null_major < 0) {
1997 for (i = 0; i < nr_devices; i++) {
1998 dev = null_alloc_dev();
2003 ret = null_add_dev(dev);
2010 pr_info("module loaded\n");
2014 while (!list_empty(&nullb_list)) {
2015 nullb = list_entry(nullb_list.next, struct nullb, list);
2017 null_del_dev(nullb);
2020 unregister_blkdev(null_major, "nullb");
2022 configfs_unregister_subsystem(&nullb_subsys);
2024 if (g_queue_mode == NULL_Q_MQ && shared_tags)
2025 blk_mq_free_tag_set(&tag_set);
2029 static void __exit null_exit(void)
2031 struct nullb *nullb;
2033 configfs_unregister_subsystem(&nullb_subsys);
2035 unregister_blkdev(null_major, "nullb");
2038 while (!list_empty(&nullb_list)) {
2039 struct nullb_device *dev;
2041 nullb = list_entry(nullb_list.next, struct nullb, list);
2043 null_del_dev(nullb);
2046 mutex_unlock(&lock);
2048 if (g_queue_mode == NULL_Q_MQ && shared_tags)
2049 blk_mq_free_tag_set(&tag_set);
2052 module_init(null_init);
2053 module_exit(null_exit);
2055 MODULE_AUTHOR("Jens Axboe <axboe@kernel.dk>");
2056 MODULE_LICENSE("GPL");