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 int g_no_sched
;
88 module_param_named(no_sched
, g_no_sched
, int, 0444);
89 MODULE_PARM_DESC(no_sched
, "No io scheduler");
91 static int g_submit_queues
= 1;
92 module_param_named(submit_queues
, g_submit_queues
, int, 0444);
93 MODULE_PARM_DESC(submit_queues
, "Number of submission queues");
95 static int g_home_node
= NUMA_NO_NODE
;
96 module_param_named(home_node
, g_home_node
, int, 0444);
97 MODULE_PARM_DESC(home_node
, "Home node for the device");
99 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
101 * For more details about fault injection, please refer to
102 * Documentation/fault-injection/fault-injection.rst.
104 static char g_timeout_str
[80];
105 module_param_string(timeout
, g_timeout_str
, sizeof(g_timeout_str
), 0444);
106 MODULE_PARM_DESC(timeout
, "Fault injection. timeout=<interval>,<probability>,<space>,<times>");
108 static char g_requeue_str
[80];
109 module_param_string(requeue
, g_requeue_str
, sizeof(g_requeue_str
), 0444);
110 MODULE_PARM_DESC(requeue
, "Fault injection. requeue=<interval>,<probability>,<space>,<times>");
112 static char g_init_hctx_str
[80];
113 module_param_string(init_hctx
, g_init_hctx_str
, sizeof(g_init_hctx_str
), 0444);
114 MODULE_PARM_DESC(init_hctx
, "Fault injection to fail hctx init. init_hctx=<interval>,<probability>,<space>,<times>");
117 static int g_queue_mode
= NULL_Q_MQ
;
119 static int null_param_store_val(const char *str
, int *val
, int min
, int max
)
123 ret
= kstrtoint(str
, 10, &new_val
);
127 if (new_val
< min
|| new_val
> max
)
134 static int null_set_queue_mode(const char *str
, const struct kernel_param
*kp
)
136 return null_param_store_val(str
, &g_queue_mode
, NULL_Q_BIO
, NULL_Q_MQ
);
139 static const struct kernel_param_ops null_queue_mode_param_ops
= {
140 .set
= null_set_queue_mode
,
141 .get
= param_get_int
,
144 device_param_cb(queue_mode
, &null_queue_mode_param_ops
, &g_queue_mode
, 0444);
145 MODULE_PARM_DESC(queue_mode
, "Block interface to use (0=bio,1=rq,2=multiqueue)");
147 static int g_gb
= 250;
148 module_param_named(gb
, g_gb
, int, 0444);
149 MODULE_PARM_DESC(gb
, "Size in GB");
151 static int g_bs
= 512;
152 module_param_named(bs
, g_bs
, int, 0444);
153 MODULE_PARM_DESC(bs
, "Block size (in bytes)");
155 static unsigned int nr_devices
= 1;
156 module_param(nr_devices
, uint
, 0444);
157 MODULE_PARM_DESC(nr_devices
, "Number of devices to register");
159 static bool g_blocking
;
160 module_param_named(blocking
, g_blocking
, bool, 0444);
161 MODULE_PARM_DESC(blocking
, "Register as a blocking blk-mq driver device");
163 static bool shared_tags
;
164 module_param(shared_tags
, bool, 0444);
165 MODULE_PARM_DESC(shared_tags
, "Share tag set between devices for blk-mq");
167 static int g_irqmode
= NULL_IRQ_SOFTIRQ
;
169 static int null_set_irqmode(const char *str
, const struct kernel_param
*kp
)
171 return null_param_store_val(str
, &g_irqmode
, NULL_IRQ_NONE
,
175 static const struct kernel_param_ops null_irqmode_param_ops
= {
176 .set
= null_set_irqmode
,
177 .get
= param_get_int
,
180 device_param_cb(irqmode
, &null_irqmode_param_ops
, &g_irqmode
, 0444);
181 MODULE_PARM_DESC(irqmode
, "IRQ completion handler. 0-none, 1-softirq, 2-timer");
183 static unsigned long g_completion_nsec
= 10000;
184 module_param_named(completion_nsec
, g_completion_nsec
, ulong
, 0444);
185 MODULE_PARM_DESC(completion_nsec
, "Time in ns to complete a request in hardware. Default: 10,000ns");
187 static int g_hw_queue_depth
= 64;
188 module_param_named(hw_queue_depth
, g_hw_queue_depth
, int, 0444);
189 MODULE_PARM_DESC(hw_queue_depth
, "Queue depth for each hardware queue. Default: 64");
191 static bool g_use_per_node_hctx
;
192 module_param_named(use_per_node_hctx
, g_use_per_node_hctx
, bool, 0444);
193 MODULE_PARM_DESC(use_per_node_hctx
, "Use per-node allocation for hardware context queues. Default: false");
196 module_param_named(zoned
, g_zoned
, bool, S_IRUGO
);
197 MODULE_PARM_DESC(zoned
, "Make device as a host-managed zoned block device. Default: false");
199 static unsigned long g_zone_size
= 256;
200 module_param_named(zone_size
, g_zone_size
, ulong
, S_IRUGO
);
201 MODULE_PARM_DESC(zone_size
, "Zone size in MB when block device is zoned. Must be power-of-two: Default: 256");
203 static unsigned int g_zone_nr_conv
;
204 module_param_named(zone_nr_conv
, g_zone_nr_conv
, uint
, 0444);
205 MODULE_PARM_DESC(zone_nr_conv
, "Number of conventional zones when block device is zoned. Default: 0");
207 static struct nullb_device
*null_alloc_dev(void);
208 static void null_free_dev(struct nullb_device
*dev
);
209 static void null_del_dev(struct nullb
*nullb
);
210 static int null_add_dev(struct nullb_device
*dev
);
211 static void null_free_device_storage(struct nullb_device
*dev
, bool is_cache
);
213 static inline struct nullb_device
*to_nullb_device(struct config_item
*item
)
215 return item
? container_of(item
, struct nullb_device
, item
) : NULL
;
218 static inline ssize_t
nullb_device_uint_attr_show(unsigned int val
, char *page
)
220 return snprintf(page
, PAGE_SIZE
, "%u\n", val
);
223 static inline ssize_t
nullb_device_ulong_attr_show(unsigned long val
,
226 return snprintf(page
, PAGE_SIZE
, "%lu\n", val
);
229 static inline ssize_t
nullb_device_bool_attr_show(bool val
, char *page
)
231 return snprintf(page
, PAGE_SIZE
, "%u\n", val
);
234 static ssize_t
nullb_device_uint_attr_store(unsigned int *val
,
235 const char *page
, size_t count
)
240 result
= kstrtouint(page
, 0, &tmp
);
248 static ssize_t
nullb_device_ulong_attr_store(unsigned long *val
,
249 const char *page
, size_t count
)
254 result
= kstrtoul(page
, 0, &tmp
);
262 static ssize_t
nullb_device_bool_attr_store(bool *val
, const char *page
,
268 result
= kstrtobool(page
, &tmp
);
276 /* The following macro should only be used with TYPE = {uint, ulong, bool}. */
277 #define NULLB_DEVICE_ATTR(NAME, TYPE, APPLY) \
279 nullb_device_##NAME##_show(struct config_item *item, char *page) \
281 return nullb_device_##TYPE##_attr_show( \
282 to_nullb_device(item)->NAME, page); \
285 nullb_device_##NAME##_store(struct config_item *item, const char *page, \
288 int (*apply_fn)(struct nullb_device *dev, TYPE new_value) = APPLY;\
289 struct nullb_device *dev = to_nullb_device(item); \
290 TYPE new_value = 0; \
293 ret = nullb_device_##TYPE##_attr_store(&new_value, page, count);\
297 ret = apply_fn(dev, new_value); \
298 else if (test_bit(NULLB_DEV_FL_CONFIGURED, &dev->flags)) \
302 dev->NAME = new_value; \
305 CONFIGFS_ATTR(nullb_device_, NAME);
307 static int nullb_apply_submit_queues(struct nullb_device
*dev
,
308 unsigned int submit_queues
)
310 struct nullb
*nullb
= dev
->nullb
;
311 struct blk_mq_tag_set
*set
;
317 * Make sure that null_init_hctx() does not access nullb->queues[] past
318 * the end of that array.
320 if (submit_queues
> nr_cpu_ids
)
322 set
= nullb
->tag_set
;
323 blk_mq_update_nr_hw_queues(set
, submit_queues
);
324 return set
->nr_hw_queues
== submit_queues
? 0 : -ENOMEM
;
327 NULLB_DEVICE_ATTR(size
, ulong
, NULL
);
328 NULLB_DEVICE_ATTR(completion_nsec
, ulong
, NULL
);
329 NULLB_DEVICE_ATTR(submit_queues
, uint
, nullb_apply_submit_queues
);
330 NULLB_DEVICE_ATTR(home_node
, uint
, NULL
);
331 NULLB_DEVICE_ATTR(queue_mode
, uint
, NULL
);
332 NULLB_DEVICE_ATTR(blocksize
, uint
, NULL
);
333 NULLB_DEVICE_ATTR(irqmode
, uint
, NULL
);
334 NULLB_DEVICE_ATTR(hw_queue_depth
, uint
, NULL
);
335 NULLB_DEVICE_ATTR(index
, uint
, NULL
);
336 NULLB_DEVICE_ATTR(blocking
, bool, NULL
);
337 NULLB_DEVICE_ATTR(use_per_node_hctx
, bool, NULL
);
338 NULLB_DEVICE_ATTR(memory_backed
, bool, NULL
);
339 NULLB_DEVICE_ATTR(discard
, bool, NULL
);
340 NULLB_DEVICE_ATTR(mbps
, uint
, NULL
);
341 NULLB_DEVICE_ATTR(cache_size
, ulong
, NULL
);
342 NULLB_DEVICE_ATTR(zoned
, bool, NULL
);
343 NULLB_DEVICE_ATTR(zone_size
, ulong
, NULL
);
344 NULLB_DEVICE_ATTR(zone_nr_conv
, uint
, NULL
);
346 static ssize_t
nullb_device_power_show(struct config_item
*item
, char *page
)
348 return nullb_device_bool_attr_show(to_nullb_device(item
)->power
, page
);
351 static ssize_t
nullb_device_power_store(struct config_item
*item
,
352 const char *page
, size_t count
)
354 struct nullb_device
*dev
= to_nullb_device(item
);
358 ret
= nullb_device_bool_attr_store(&newp
, page
, count
);
362 if (!dev
->power
&& newp
) {
363 if (test_and_set_bit(NULLB_DEV_FL_UP
, &dev
->flags
))
365 if (null_add_dev(dev
)) {
366 clear_bit(NULLB_DEV_FL_UP
, &dev
->flags
);
370 set_bit(NULLB_DEV_FL_CONFIGURED
, &dev
->flags
);
372 } else if (dev
->power
&& !newp
) {
373 if (test_and_clear_bit(NULLB_DEV_FL_UP
, &dev
->flags
)) {
376 null_del_dev(dev
->nullb
);
379 clear_bit(NULLB_DEV_FL_CONFIGURED
, &dev
->flags
);
385 CONFIGFS_ATTR(nullb_device_
, power
);
387 static ssize_t
nullb_device_badblocks_show(struct config_item
*item
, char *page
)
389 struct nullb_device
*t_dev
= to_nullb_device(item
);
391 return badblocks_show(&t_dev
->badblocks
, page
, 0);
394 static ssize_t
nullb_device_badblocks_store(struct config_item
*item
,
395 const char *page
, size_t count
)
397 struct nullb_device
*t_dev
= to_nullb_device(item
);
398 char *orig
, *buf
, *tmp
;
402 orig
= kstrndup(page
, count
, GFP_KERNEL
);
406 buf
= strstrip(orig
);
409 if (buf
[0] != '+' && buf
[0] != '-')
411 tmp
= strchr(&buf
[1], '-');
415 ret
= kstrtoull(buf
+ 1, 0, &start
);
418 ret
= kstrtoull(tmp
+ 1, 0, &end
);
424 /* enable badblocks */
425 cmpxchg(&t_dev
->badblocks
.shift
, -1, 0);
427 ret
= badblocks_set(&t_dev
->badblocks
, start
,
430 ret
= badblocks_clear(&t_dev
->badblocks
, start
,
438 CONFIGFS_ATTR(nullb_device_
, badblocks
);
440 static struct configfs_attribute
*nullb_device_attrs
[] = {
441 &nullb_device_attr_size
,
442 &nullb_device_attr_completion_nsec
,
443 &nullb_device_attr_submit_queues
,
444 &nullb_device_attr_home_node
,
445 &nullb_device_attr_queue_mode
,
446 &nullb_device_attr_blocksize
,
447 &nullb_device_attr_irqmode
,
448 &nullb_device_attr_hw_queue_depth
,
449 &nullb_device_attr_index
,
450 &nullb_device_attr_blocking
,
451 &nullb_device_attr_use_per_node_hctx
,
452 &nullb_device_attr_power
,
453 &nullb_device_attr_memory_backed
,
454 &nullb_device_attr_discard
,
455 &nullb_device_attr_mbps
,
456 &nullb_device_attr_cache_size
,
457 &nullb_device_attr_badblocks
,
458 &nullb_device_attr_zoned
,
459 &nullb_device_attr_zone_size
,
460 &nullb_device_attr_zone_nr_conv
,
464 static void nullb_device_release(struct config_item
*item
)
466 struct nullb_device
*dev
= to_nullb_device(item
);
468 null_free_device_storage(dev
, false);
472 static struct configfs_item_operations nullb_device_ops
= {
473 .release
= nullb_device_release
,
476 static const struct config_item_type nullb_device_type
= {
477 .ct_item_ops
= &nullb_device_ops
,
478 .ct_attrs
= nullb_device_attrs
,
479 .ct_owner
= THIS_MODULE
,
483 config_item
*nullb_group_make_item(struct config_group
*group
, const char *name
)
485 struct nullb_device
*dev
;
487 dev
= null_alloc_dev();
489 return ERR_PTR(-ENOMEM
);
491 config_item_init_type_name(&dev
->item
, name
, &nullb_device_type
);
497 nullb_group_drop_item(struct config_group
*group
, struct config_item
*item
)
499 struct nullb_device
*dev
= to_nullb_device(item
);
501 if (test_and_clear_bit(NULLB_DEV_FL_UP
, &dev
->flags
)) {
504 null_del_dev(dev
->nullb
);
508 config_item_put(item
);
511 static ssize_t
memb_group_features_show(struct config_item
*item
, char *page
)
513 return snprintf(page
, PAGE_SIZE
, "memory_backed,discard,bandwidth,cache,badblocks,zoned,zone_size,zone_nr_conv\n");
516 CONFIGFS_ATTR_RO(memb_group_
, features
);
518 static struct configfs_attribute
*nullb_group_attrs
[] = {
519 &memb_group_attr_features
,
523 static struct configfs_group_operations nullb_group_ops
= {
524 .make_item
= nullb_group_make_item
,
525 .drop_item
= nullb_group_drop_item
,
528 static const struct config_item_type nullb_group_type
= {
529 .ct_group_ops
= &nullb_group_ops
,
530 .ct_attrs
= nullb_group_attrs
,
531 .ct_owner
= THIS_MODULE
,
534 static struct configfs_subsystem nullb_subsys
= {
537 .ci_namebuf
= "nullb",
538 .ci_type
= &nullb_group_type
,
543 static inline int null_cache_active(struct nullb
*nullb
)
545 return test_bit(NULLB_DEV_FL_CACHE
, &nullb
->dev
->flags
);
548 static struct nullb_device
*null_alloc_dev(void)
550 struct nullb_device
*dev
;
552 dev
= kzalloc(sizeof(*dev
), GFP_KERNEL
);
555 INIT_RADIX_TREE(&dev
->data
, GFP_ATOMIC
);
556 INIT_RADIX_TREE(&dev
->cache
, GFP_ATOMIC
);
557 if (badblocks_init(&dev
->badblocks
, 0)) {
562 dev
->size
= g_gb
* 1024;
563 dev
->completion_nsec
= g_completion_nsec
;
564 dev
->submit_queues
= g_submit_queues
;
565 dev
->home_node
= g_home_node
;
566 dev
->queue_mode
= g_queue_mode
;
567 dev
->blocksize
= g_bs
;
568 dev
->irqmode
= g_irqmode
;
569 dev
->hw_queue_depth
= g_hw_queue_depth
;
570 dev
->blocking
= g_blocking
;
571 dev
->use_per_node_hctx
= g_use_per_node_hctx
;
572 dev
->zoned
= g_zoned
;
573 dev
->zone_size
= g_zone_size
;
574 dev
->zone_nr_conv
= g_zone_nr_conv
;
578 static void null_free_dev(struct nullb_device
*dev
)
583 null_free_zoned_dev(dev
);
584 badblocks_exit(&dev
->badblocks
);
588 static void put_tag(struct nullb_queue
*nq
, unsigned int tag
)
590 clear_bit_unlock(tag
, nq
->tag_map
);
592 if (waitqueue_active(&nq
->wait
))
596 static unsigned int get_tag(struct nullb_queue
*nq
)
601 tag
= find_first_zero_bit(nq
->tag_map
, nq
->queue_depth
);
602 if (tag
>= nq
->queue_depth
)
604 } while (test_and_set_bit_lock(tag
, nq
->tag_map
));
609 static void free_cmd(struct nullb_cmd
*cmd
)
611 put_tag(cmd
->nq
, cmd
->tag
);
614 static enum hrtimer_restart
null_cmd_timer_expired(struct hrtimer
*timer
);
616 static struct nullb_cmd
*__alloc_cmd(struct nullb_queue
*nq
)
618 struct nullb_cmd
*cmd
;
623 cmd
= &nq
->cmds
[tag
];
625 cmd
->error
= BLK_STS_OK
;
627 if (nq
->dev
->irqmode
== NULL_IRQ_TIMER
) {
628 hrtimer_init(&cmd
->timer
, CLOCK_MONOTONIC
,
630 cmd
->timer
.function
= null_cmd_timer_expired
;
638 static struct nullb_cmd
*alloc_cmd(struct nullb_queue
*nq
, int can_wait
)
640 struct nullb_cmd
*cmd
;
643 cmd
= __alloc_cmd(nq
);
644 if (cmd
|| !can_wait
)
648 prepare_to_wait(&nq
->wait
, &wait
, TASK_UNINTERRUPTIBLE
);
649 cmd
= __alloc_cmd(nq
);
656 finish_wait(&nq
->wait
, &wait
);
660 static void end_cmd(struct nullb_cmd
*cmd
)
662 int queue_mode
= cmd
->nq
->dev
->queue_mode
;
664 switch (queue_mode
) {
666 blk_mq_end_request(cmd
->rq
, cmd
->error
);
669 cmd
->bio
->bi_status
= cmd
->error
;
677 static enum hrtimer_restart
null_cmd_timer_expired(struct hrtimer
*timer
)
679 end_cmd(container_of(timer
, struct nullb_cmd
, timer
));
681 return HRTIMER_NORESTART
;
684 static void null_cmd_end_timer(struct nullb_cmd
*cmd
)
686 ktime_t kt
= cmd
->nq
->dev
->completion_nsec
;
688 hrtimer_start(&cmd
->timer
, kt
, HRTIMER_MODE_REL
);
691 static void null_complete_rq(struct request
*rq
)
693 end_cmd(blk_mq_rq_to_pdu(rq
));
696 static struct nullb_page
*null_alloc_page(gfp_t gfp_flags
)
698 struct nullb_page
*t_page
;
700 t_page
= kmalloc(sizeof(struct nullb_page
), gfp_flags
);
704 t_page
->page
= alloc_pages(gfp_flags
, 0);
708 memset(t_page
->bitmap
, 0, sizeof(t_page
->bitmap
));
716 static void null_free_page(struct nullb_page
*t_page
)
718 __set_bit(NULLB_PAGE_FREE
, t_page
->bitmap
);
719 if (test_bit(NULLB_PAGE_LOCK
, t_page
->bitmap
))
721 __free_page(t_page
->page
);
725 static bool null_page_empty(struct nullb_page
*page
)
727 int size
= MAP_SZ
- 2;
729 return find_first_bit(page
->bitmap
, size
) == size
;
732 static void null_free_sector(struct nullb
*nullb
, sector_t sector
,
735 unsigned int sector_bit
;
737 struct nullb_page
*t_page
, *ret
;
738 struct radix_tree_root
*root
;
740 root
= is_cache
? &nullb
->dev
->cache
: &nullb
->dev
->data
;
741 idx
= sector
>> PAGE_SECTORS_SHIFT
;
742 sector_bit
= (sector
& SECTOR_MASK
);
744 t_page
= radix_tree_lookup(root
, idx
);
746 __clear_bit(sector_bit
, t_page
->bitmap
);
748 if (null_page_empty(t_page
)) {
749 ret
= radix_tree_delete_item(root
, idx
, t_page
);
750 WARN_ON(ret
!= t_page
);
753 nullb
->dev
->curr_cache
-= PAGE_SIZE
;
758 static struct nullb_page
*null_radix_tree_insert(struct nullb
*nullb
, u64 idx
,
759 struct nullb_page
*t_page
, bool is_cache
)
761 struct radix_tree_root
*root
;
763 root
= is_cache
? &nullb
->dev
->cache
: &nullb
->dev
->data
;
765 if (radix_tree_insert(root
, idx
, t_page
)) {
766 null_free_page(t_page
);
767 t_page
= radix_tree_lookup(root
, idx
);
768 WARN_ON(!t_page
|| t_page
->page
->index
!= idx
);
770 nullb
->dev
->curr_cache
+= PAGE_SIZE
;
775 static void null_free_device_storage(struct nullb_device
*dev
, bool is_cache
)
777 unsigned long pos
= 0;
779 struct nullb_page
*ret
, *t_pages
[FREE_BATCH
];
780 struct radix_tree_root
*root
;
782 root
= is_cache
? &dev
->cache
: &dev
->data
;
787 nr_pages
= radix_tree_gang_lookup(root
,
788 (void **)t_pages
, pos
, FREE_BATCH
);
790 for (i
= 0; i
< nr_pages
; i
++) {
791 pos
= t_pages
[i
]->page
->index
;
792 ret
= radix_tree_delete_item(root
, pos
, t_pages
[i
]);
793 WARN_ON(ret
!= t_pages
[i
]);
798 } while (nr_pages
== FREE_BATCH
);
804 static struct nullb_page
*__null_lookup_page(struct nullb
*nullb
,
805 sector_t sector
, bool for_write
, bool is_cache
)
807 unsigned int sector_bit
;
809 struct nullb_page
*t_page
;
810 struct radix_tree_root
*root
;
812 idx
= sector
>> PAGE_SECTORS_SHIFT
;
813 sector_bit
= (sector
& SECTOR_MASK
);
815 root
= is_cache
? &nullb
->dev
->cache
: &nullb
->dev
->data
;
816 t_page
= radix_tree_lookup(root
, idx
);
817 WARN_ON(t_page
&& t_page
->page
->index
!= idx
);
819 if (t_page
&& (for_write
|| test_bit(sector_bit
, t_page
->bitmap
)))
825 static struct nullb_page
*null_lookup_page(struct nullb
*nullb
,
826 sector_t sector
, bool for_write
, bool ignore_cache
)
828 struct nullb_page
*page
= NULL
;
831 page
= __null_lookup_page(nullb
, sector
, for_write
, true);
834 return __null_lookup_page(nullb
, sector
, for_write
, false);
837 static struct nullb_page
*null_insert_page(struct nullb
*nullb
,
838 sector_t sector
, bool ignore_cache
)
839 __releases(&nullb
->lock
)
840 __acquires(&nullb
->lock
)
843 struct nullb_page
*t_page
;
845 t_page
= null_lookup_page(nullb
, sector
, true, ignore_cache
);
849 spin_unlock_irq(&nullb
->lock
);
851 t_page
= null_alloc_page(GFP_NOIO
);
855 if (radix_tree_preload(GFP_NOIO
))
858 spin_lock_irq(&nullb
->lock
);
859 idx
= sector
>> PAGE_SECTORS_SHIFT
;
860 t_page
->page
->index
= idx
;
861 t_page
= null_radix_tree_insert(nullb
, idx
, t_page
, !ignore_cache
);
862 radix_tree_preload_end();
866 null_free_page(t_page
);
868 spin_lock_irq(&nullb
->lock
);
869 return null_lookup_page(nullb
, sector
, true, ignore_cache
);
872 static int null_flush_cache_page(struct nullb
*nullb
, struct nullb_page
*c_page
)
877 struct nullb_page
*t_page
, *ret
;
880 idx
= c_page
->page
->index
;
882 t_page
= null_insert_page(nullb
, idx
<< PAGE_SECTORS_SHIFT
, true);
884 __clear_bit(NULLB_PAGE_LOCK
, c_page
->bitmap
);
885 if (test_bit(NULLB_PAGE_FREE
, c_page
->bitmap
)) {
886 null_free_page(c_page
);
887 if (t_page
&& null_page_empty(t_page
)) {
888 ret
= radix_tree_delete_item(&nullb
->dev
->data
,
890 null_free_page(t_page
);
898 src
= kmap_atomic(c_page
->page
);
899 dst
= kmap_atomic(t_page
->page
);
901 for (i
= 0; i
< PAGE_SECTORS
;
902 i
+= (nullb
->dev
->blocksize
>> SECTOR_SHIFT
)) {
903 if (test_bit(i
, c_page
->bitmap
)) {
904 offset
= (i
<< SECTOR_SHIFT
);
905 memcpy(dst
+ offset
, src
+ offset
,
906 nullb
->dev
->blocksize
);
907 __set_bit(i
, t_page
->bitmap
);
914 ret
= radix_tree_delete_item(&nullb
->dev
->cache
, idx
, c_page
);
916 nullb
->dev
->curr_cache
-= PAGE_SIZE
;
921 static int null_make_cache_space(struct nullb
*nullb
, unsigned long n
)
923 int i
, err
, nr_pages
;
924 struct nullb_page
*c_pages
[FREE_BATCH
];
925 unsigned long flushed
= 0, one_round
;
928 if ((nullb
->dev
->cache_size
* 1024 * 1024) >
929 nullb
->dev
->curr_cache
+ n
|| nullb
->dev
->curr_cache
== 0)
932 nr_pages
= radix_tree_gang_lookup(&nullb
->dev
->cache
,
933 (void **)c_pages
, nullb
->cache_flush_pos
, FREE_BATCH
);
935 * nullb_flush_cache_page could unlock before using the c_pages. To
936 * avoid race, we don't allow page free
938 for (i
= 0; i
< nr_pages
; i
++) {
939 nullb
->cache_flush_pos
= c_pages
[i
]->page
->index
;
941 * We found the page which is being flushed to disk by other
944 if (test_bit(NULLB_PAGE_LOCK
, c_pages
[i
]->bitmap
))
947 __set_bit(NULLB_PAGE_LOCK
, c_pages
[i
]->bitmap
);
951 for (i
= 0; i
< nr_pages
; i
++) {
952 if (c_pages
[i
] == NULL
)
954 err
= null_flush_cache_page(nullb
, c_pages
[i
]);
959 flushed
+= one_round
<< PAGE_SHIFT
;
963 nullb
->cache_flush_pos
= 0;
964 if (one_round
== 0) {
965 /* give other threads a chance */
966 spin_unlock_irq(&nullb
->lock
);
967 spin_lock_irq(&nullb
->lock
);
974 static int copy_to_nullb(struct nullb
*nullb
, struct page
*source
,
975 unsigned int off
, sector_t sector
, size_t n
, bool is_fua
)
977 size_t temp
, count
= 0;
979 struct nullb_page
*t_page
;
983 temp
= min_t(size_t, nullb
->dev
->blocksize
, n
- count
);
985 if (null_cache_active(nullb
) && !is_fua
)
986 null_make_cache_space(nullb
, PAGE_SIZE
);
988 offset
= (sector
& SECTOR_MASK
) << SECTOR_SHIFT
;
989 t_page
= null_insert_page(nullb
, sector
,
990 !null_cache_active(nullb
) || is_fua
);
994 src
= kmap_atomic(source
);
995 dst
= kmap_atomic(t_page
->page
);
996 memcpy(dst
+ offset
, src
+ off
+ count
, temp
);
1000 __set_bit(sector
& SECTOR_MASK
, t_page
->bitmap
);
1003 null_free_sector(nullb
, sector
, true);
1006 sector
+= temp
>> SECTOR_SHIFT
;
1011 static int copy_from_nullb(struct nullb
*nullb
, struct page
*dest
,
1012 unsigned int off
, sector_t sector
, size_t n
)
1014 size_t temp
, count
= 0;
1015 unsigned int offset
;
1016 struct nullb_page
*t_page
;
1020 temp
= min_t(size_t, nullb
->dev
->blocksize
, n
- count
);
1022 offset
= (sector
& SECTOR_MASK
) << SECTOR_SHIFT
;
1023 t_page
= null_lookup_page(nullb
, sector
, false,
1024 !null_cache_active(nullb
));
1026 dst
= kmap_atomic(dest
);
1028 memset(dst
+ off
+ count
, 0, temp
);
1031 src
= kmap_atomic(t_page
->page
);
1032 memcpy(dst
+ off
+ count
, src
+ offset
, temp
);
1038 sector
+= temp
>> SECTOR_SHIFT
;
1043 static void nullb_fill_pattern(struct nullb
*nullb
, struct page
*page
,
1044 unsigned int len
, unsigned int off
)
1048 dst
= kmap_atomic(page
);
1049 memset(dst
+ off
, 0xFF, len
);
1053 static void null_handle_discard(struct nullb
*nullb
, sector_t sector
, size_t n
)
1057 spin_lock_irq(&nullb
->lock
);
1059 temp
= min_t(size_t, n
, nullb
->dev
->blocksize
);
1060 null_free_sector(nullb
, sector
, false);
1061 if (null_cache_active(nullb
))
1062 null_free_sector(nullb
, sector
, true);
1063 sector
+= temp
>> SECTOR_SHIFT
;
1066 spin_unlock_irq(&nullb
->lock
);
1069 static int null_handle_flush(struct nullb
*nullb
)
1073 if (!null_cache_active(nullb
))
1076 spin_lock_irq(&nullb
->lock
);
1078 err
= null_make_cache_space(nullb
,
1079 nullb
->dev
->cache_size
* 1024 * 1024);
1080 if (err
|| nullb
->dev
->curr_cache
== 0)
1084 WARN_ON(!radix_tree_empty(&nullb
->dev
->cache
));
1085 spin_unlock_irq(&nullb
->lock
);
1089 static int null_transfer(struct nullb
*nullb
, struct page
*page
,
1090 unsigned int len
, unsigned int off
, bool is_write
, sector_t sector
,
1093 struct nullb_device
*dev
= nullb
->dev
;
1094 unsigned int valid_len
= len
;
1099 valid_len
= null_zone_valid_read_len(nullb
,
1103 err
= copy_from_nullb(nullb
, page
, off
,
1110 nullb_fill_pattern(nullb
, page
, len
, off
);
1111 flush_dcache_page(page
);
1113 flush_dcache_page(page
);
1114 err
= copy_to_nullb(nullb
, page
, off
, sector
, len
, is_fua
);
1120 static int null_handle_rq(struct nullb_cmd
*cmd
)
1122 struct request
*rq
= cmd
->rq
;
1123 struct nullb
*nullb
= cmd
->nq
->dev
->nullb
;
1127 struct req_iterator iter
;
1128 struct bio_vec bvec
;
1130 sector
= blk_rq_pos(rq
);
1132 if (req_op(rq
) == REQ_OP_DISCARD
) {
1133 null_handle_discard(nullb
, sector
, blk_rq_bytes(rq
));
1137 spin_lock_irq(&nullb
->lock
);
1138 rq_for_each_segment(bvec
, rq
, iter
) {
1140 err
= null_transfer(nullb
, bvec
.bv_page
, len
, bvec
.bv_offset
,
1141 op_is_write(req_op(rq
)), sector
,
1142 req_op(rq
) & REQ_FUA
);
1144 spin_unlock_irq(&nullb
->lock
);
1147 sector
+= len
>> SECTOR_SHIFT
;
1149 spin_unlock_irq(&nullb
->lock
);
1154 static int null_handle_bio(struct nullb_cmd
*cmd
)
1156 struct bio
*bio
= cmd
->bio
;
1157 struct nullb
*nullb
= cmd
->nq
->dev
->nullb
;
1161 struct bio_vec bvec
;
1162 struct bvec_iter iter
;
1164 sector
= bio
->bi_iter
.bi_sector
;
1166 if (bio_op(bio
) == REQ_OP_DISCARD
) {
1167 null_handle_discard(nullb
, sector
,
1168 bio_sectors(bio
) << SECTOR_SHIFT
);
1172 spin_lock_irq(&nullb
->lock
);
1173 bio_for_each_segment(bvec
, bio
, iter
) {
1175 err
= null_transfer(nullb
, bvec
.bv_page
, len
, bvec
.bv_offset
,
1176 op_is_write(bio_op(bio
)), sector
,
1177 bio
->bi_opf
& REQ_FUA
);
1179 spin_unlock_irq(&nullb
->lock
);
1182 sector
+= len
>> SECTOR_SHIFT
;
1184 spin_unlock_irq(&nullb
->lock
);
1188 static void null_stop_queue(struct nullb
*nullb
)
1190 struct request_queue
*q
= nullb
->q
;
1192 if (nullb
->dev
->queue_mode
== NULL_Q_MQ
)
1193 blk_mq_stop_hw_queues(q
);
1196 static void null_restart_queue_async(struct nullb
*nullb
)
1198 struct request_queue
*q
= nullb
->q
;
1200 if (nullb
->dev
->queue_mode
== NULL_Q_MQ
)
1201 blk_mq_start_stopped_hw_queues(q
, true);
1204 static inline blk_status_t
null_handle_throttled(struct nullb_cmd
*cmd
)
1206 struct nullb_device
*dev
= cmd
->nq
->dev
;
1207 struct nullb
*nullb
= dev
->nullb
;
1208 blk_status_t sts
= BLK_STS_OK
;
1209 struct request
*rq
= cmd
->rq
;
1211 if (!hrtimer_active(&nullb
->bw_timer
))
1212 hrtimer_restart(&nullb
->bw_timer
);
1214 if (atomic_long_sub_return(blk_rq_bytes(rq
), &nullb
->cur_bytes
) < 0) {
1215 null_stop_queue(nullb
);
1216 /* race with timer */
1217 if (atomic_long_read(&nullb
->cur_bytes
) > 0)
1218 null_restart_queue_async(nullb
);
1219 /* requeue request */
1220 sts
= BLK_STS_DEV_RESOURCE
;
1225 static inline blk_status_t
null_handle_badblocks(struct nullb_cmd
*cmd
,
1227 sector_t nr_sectors
)
1229 struct badblocks
*bb
= &cmd
->nq
->dev
->badblocks
;
1233 if (badblocks_check(bb
, sector
, nr_sectors
, &first_bad
, &bad_sectors
))
1234 return BLK_STS_IOERR
;
1239 static inline blk_status_t
null_handle_memory_backed(struct nullb_cmd
*cmd
,
1242 struct nullb_device
*dev
= cmd
->nq
->dev
;
1245 if (dev
->queue_mode
== NULL_Q_BIO
)
1246 err
= null_handle_bio(cmd
);
1248 err
= null_handle_rq(cmd
);
1250 return errno_to_blk_status(err
);
1253 static void nullb_zero_read_cmd_buffer(struct nullb_cmd
*cmd
)
1255 struct nullb_device
*dev
= cmd
->nq
->dev
;
1258 if (dev
->memory_backed
)
1261 if (dev
->queue_mode
== NULL_Q_BIO
&& bio_op(cmd
->bio
) == REQ_OP_READ
) {
1262 zero_fill_bio(cmd
->bio
);
1263 } else if (req_op(cmd
->rq
) == REQ_OP_READ
) {
1264 __rq_for_each_bio(bio
, cmd
->rq
)
1269 static inline void nullb_complete_cmd(struct nullb_cmd
*cmd
)
1272 * Since root privileges are required to configure the null_blk
1273 * driver, it is fine that this driver does not initialize the
1274 * data buffers of read commands. Zero-initialize these buffers
1275 * anyway if KMSAN is enabled to prevent that KMSAN complains
1276 * about null_blk not initializing read data buffers.
1278 if (IS_ENABLED(CONFIG_KMSAN
))
1279 nullb_zero_read_cmd_buffer(cmd
);
1281 /* Complete IO by inline, softirq or timer */
1282 switch (cmd
->nq
->dev
->irqmode
) {
1283 case NULL_IRQ_SOFTIRQ
:
1284 switch (cmd
->nq
->dev
->queue_mode
) {
1286 blk_mq_complete_request(cmd
->rq
);
1290 * XXX: no proper submitting cpu information available.
1299 case NULL_IRQ_TIMER
:
1300 null_cmd_end_timer(cmd
);
1305 blk_status_t
null_process_cmd(struct nullb_cmd
*cmd
,
1306 enum req_opf op
, sector_t sector
,
1307 unsigned int nr_sectors
)
1309 struct nullb_device
*dev
= cmd
->nq
->dev
;
1312 if (dev
->badblocks
.shift
!= -1) {
1313 ret
= null_handle_badblocks(cmd
, sector
, nr_sectors
);
1314 if (ret
!= BLK_STS_OK
)
1318 if (dev
->memory_backed
)
1319 return null_handle_memory_backed(cmd
, op
);
1324 static blk_status_t
null_handle_cmd(struct nullb_cmd
*cmd
, sector_t sector
,
1325 sector_t nr_sectors
, enum req_opf op
)
1327 struct nullb_device
*dev
= cmd
->nq
->dev
;
1328 struct nullb
*nullb
= dev
->nullb
;
1331 if (test_bit(NULLB_DEV_FL_THROTTLED
, &dev
->flags
)) {
1332 sts
= null_handle_throttled(cmd
);
1333 if (sts
!= BLK_STS_OK
)
1337 if (op
== REQ_OP_FLUSH
) {
1338 cmd
->error
= errno_to_blk_status(null_handle_flush(nullb
));
1343 cmd
->error
= null_process_zoned_cmd(cmd
, op
,
1344 sector
, nr_sectors
);
1346 cmd
->error
= null_process_cmd(cmd
, op
, sector
, nr_sectors
);
1349 nullb_complete_cmd(cmd
);
1353 static enum hrtimer_restart
nullb_bwtimer_fn(struct hrtimer
*timer
)
1355 struct nullb
*nullb
= container_of(timer
, struct nullb
, bw_timer
);
1356 ktime_t timer_interval
= ktime_set(0, TIMER_INTERVAL
);
1357 unsigned int mbps
= nullb
->dev
->mbps
;
1359 if (atomic_long_read(&nullb
->cur_bytes
) == mb_per_tick(mbps
))
1360 return HRTIMER_NORESTART
;
1362 atomic_long_set(&nullb
->cur_bytes
, mb_per_tick(mbps
));
1363 null_restart_queue_async(nullb
);
1365 hrtimer_forward_now(&nullb
->bw_timer
, timer_interval
);
1367 return HRTIMER_RESTART
;
1370 static void nullb_setup_bwtimer(struct nullb
*nullb
)
1372 ktime_t timer_interval
= ktime_set(0, TIMER_INTERVAL
);
1374 hrtimer_init(&nullb
->bw_timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
1375 nullb
->bw_timer
.function
= nullb_bwtimer_fn
;
1376 atomic_long_set(&nullb
->cur_bytes
, mb_per_tick(nullb
->dev
->mbps
));
1377 hrtimer_start(&nullb
->bw_timer
, timer_interval
, HRTIMER_MODE_REL
);
1380 static struct nullb_queue
*nullb_to_queue(struct nullb
*nullb
)
1384 if (nullb
->nr_queues
!= 1)
1385 index
= raw_smp_processor_id() / ((nr_cpu_ids
+ nullb
->nr_queues
- 1) / nullb
->nr_queues
);
1387 return &nullb
->queues
[index
];
1390 static blk_qc_t
null_queue_bio(struct request_queue
*q
, struct bio
*bio
)
1392 sector_t sector
= bio
->bi_iter
.bi_sector
;
1393 sector_t nr_sectors
= bio_sectors(bio
);
1394 struct nullb
*nullb
= q
->queuedata
;
1395 struct nullb_queue
*nq
= nullb_to_queue(nullb
);
1396 struct nullb_cmd
*cmd
;
1398 cmd
= alloc_cmd(nq
, 1);
1401 null_handle_cmd(cmd
, sector
, nr_sectors
, bio_op(bio
));
1402 return BLK_QC_T_NONE
;
1405 static bool should_timeout_request(struct request
*rq
)
1407 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
1408 if (g_timeout_str
[0])
1409 return should_fail(&null_timeout_attr
, 1);
1414 static bool should_requeue_request(struct request
*rq
)
1416 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
1417 if (g_requeue_str
[0])
1418 return should_fail(&null_requeue_attr
, 1);
1423 static enum blk_eh_timer_return
null_timeout_rq(struct request
*rq
, bool res
)
1425 pr_info("rq %p timed out\n", rq
);
1426 blk_mq_force_complete_rq(rq
);
1430 static blk_status_t
null_queue_rq(struct blk_mq_hw_ctx
*hctx
,
1431 const struct blk_mq_queue_data
*bd
)
1433 struct nullb_cmd
*cmd
= blk_mq_rq_to_pdu(bd
->rq
);
1434 struct nullb_queue
*nq
= hctx
->driver_data
;
1435 sector_t nr_sectors
= blk_rq_sectors(bd
->rq
);
1436 sector_t sector
= blk_rq_pos(bd
->rq
);
1438 might_sleep_if(hctx
->flags
& BLK_MQ_F_BLOCKING
);
1440 if (nq
->dev
->irqmode
== NULL_IRQ_TIMER
) {
1441 hrtimer_init(&cmd
->timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
1442 cmd
->timer
.function
= null_cmd_timer_expired
;
1445 cmd
->error
= BLK_STS_OK
;
1448 blk_mq_start_request(bd
->rq
);
1450 if (should_requeue_request(bd
->rq
)) {
1452 * Alternate between hitting the core BUSY path, and the
1453 * driver driven requeue path
1455 nq
->requeue_selection
++;
1456 if (nq
->requeue_selection
& 1)
1457 return BLK_STS_RESOURCE
;
1459 blk_mq_requeue_request(bd
->rq
, true);
1463 if (should_timeout_request(bd
->rq
))
1466 return null_handle_cmd(cmd
, sector
, nr_sectors
, req_op(bd
->rq
));
1469 static void cleanup_queue(struct nullb_queue
*nq
)
1475 static void cleanup_queues(struct nullb
*nullb
)
1479 for (i
= 0; i
< nullb
->nr_queues
; i
++)
1480 cleanup_queue(&nullb
->queues
[i
]);
1482 kfree(nullb
->queues
);
1485 static void null_exit_hctx(struct blk_mq_hw_ctx
*hctx
, unsigned int hctx_idx
)
1487 struct nullb_queue
*nq
= hctx
->driver_data
;
1488 struct nullb
*nullb
= nq
->dev
->nullb
;
1493 static void null_init_queue(struct nullb
*nullb
, struct nullb_queue
*nq
)
1495 init_waitqueue_head(&nq
->wait
);
1496 nq
->queue_depth
= nullb
->queue_depth
;
1497 nq
->dev
= nullb
->dev
;
1500 static int null_init_hctx(struct blk_mq_hw_ctx
*hctx
, void *driver_data
,
1501 unsigned int hctx_idx
)
1503 struct nullb
*nullb
= hctx
->queue
->queuedata
;
1504 struct nullb_queue
*nq
;
1506 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
1507 if (g_init_hctx_str
[0] && should_fail(&null_init_hctx_attr
, 1))
1511 nq
= &nullb
->queues
[hctx_idx
];
1512 hctx
->driver_data
= nq
;
1513 null_init_queue(nullb
, nq
);
1519 static const struct blk_mq_ops null_mq_ops
= {
1520 .queue_rq
= null_queue_rq
,
1521 .complete
= null_complete_rq
,
1522 .timeout
= null_timeout_rq
,
1523 .init_hctx
= null_init_hctx
,
1524 .exit_hctx
= null_exit_hctx
,
1527 static void null_del_dev(struct nullb
*nullb
)
1529 struct nullb_device
*dev
;
1536 ida_simple_remove(&nullb_indexes
, nullb
->index
);
1538 list_del_init(&nullb
->list
);
1540 del_gendisk(nullb
->disk
);
1542 if (test_bit(NULLB_DEV_FL_THROTTLED
, &nullb
->dev
->flags
)) {
1543 hrtimer_cancel(&nullb
->bw_timer
);
1544 atomic_long_set(&nullb
->cur_bytes
, LONG_MAX
);
1545 null_restart_queue_async(nullb
);
1548 blk_cleanup_queue(nullb
->q
);
1549 if (dev
->queue_mode
== NULL_Q_MQ
&&
1550 nullb
->tag_set
== &nullb
->__tag_set
)
1551 blk_mq_free_tag_set(nullb
->tag_set
);
1552 put_disk(nullb
->disk
);
1553 cleanup_queues(nullb
);
1554 if (null_cache_active(nullb
))
1555 null_free_device_storage(nullb
->dev
, true);
1560 static void null_config_discard(struct nullb
*nullb
)
1562 if (nullb
->dev
->discard
== false)
1565 if (nullb
->dev
->zoned
) {
1566 nullb
->dev
->discard
= false;
1567 pr_info("discard option is ignored in zoned mode\n");
1571 nullb
->q
->limits
.discard_granularity
= nullb
->dev
->blocksize
;
1572 nullb
->q
->limits
.discard_alignment
= nullb
->dev
->blocksize
;
1573 blk_queue_max_discard_sectors(nullb
->q
, UINT_MAX
>> 9);
1574 blk_queue_flag_set(QUEUE_FLAG_DISCARD
, nullb
->q
);
1577 static const struct block_device_operations null_ops
= {
1578 .owner
= THIS_MODULE
,
1579 .report_zones
= null_report_zones
,
1582 static int setup_commands(struct nullb_queue
*nq
)
1584 struct nullb_cmd
*cmd
;
1587 nq
->cmds
= kcalloc(nq
->queue_depth
, sizeof(*cmd
), GFP_KERNEL
);
1591 tag_size
= ALIGN(nq
->queue_depth
, BITS_PER_LONG
) / BITS_PER_LONG
;
1592 nq
->tag_map
= kcalloc(tag_size
, sizeof(unsigned long), GFP_KERNEL
);
1598 for (i
= 0; i
< nq
->queue_depth
; i
++) {
1606 static int setup_queues(struct nullb
*nullb
)
1608 nullb
->queues
= kcalloc(nr_cpu_ids
, sizeof(struct nullb_queue
),
1613 nullb
->queue_depth
= nullb
->dev
->hw_queue_depth
;
1618 static int init_driver_queues(struct nullb
*nullb
)
1620 struct nullb_queue
*nq
;
1623 for (i
= 0; i
< nullb
->dev
->submit_queues
; i
++) {
1624 nq
= &nullb
->queues
[i
];
1626 null_init_queue(nullb
, nq
);
1628 ret
= setup_commands(nq
);
1636 static int null_gendisk_register(struct nullb
*nullb
)
1638 sector_t size
= ((sector_t
)nullb
->dev
->size
* SZ_1M
) >> SECTOR_SHIFT
;
1639 struct gendisk
*disk
;
1641 disk
= nullb
->disk
= alloc_disk_node(1, nullb
->dev
->home_node
);
1644 set_capacity(disk
, size
);
1646 disk
->flags
|= GENHD_FL_EXT_DEVT
| GENHD_FL_SUPPRESS_PARTITION_INFO
;
1647 disk
->major
= null_major
;
1648 disk
->first_minor
= nullb
->index
;
1649 disk
->fops
= &null_ops
;
1650 disk
->private_data
= nullb
;
1651 disk
->queue
= nullb
->q
;
1652 strncpy(disk
->disk_name
, nullb
->disk_name
, DISK_NAME_LEN
);
1654 if (nullb
->dev
->zoned
) {
1655 int ret
= null_register_zoned_dev(nullb
);
1665 static int null_init_tag_set(struct nullb
*nullb
, struct blk_mq_tag_set
*set
)
1667 set
->ops
= &null_mq_ops
;
1668 set
->nr_hw_queues
= nullb
? nullb
->dev
->submit_queues
:
1670 set
->queue_depth
= nullb
? nullb
->dev
->hw_queue_depth
:
1672 set
->numa_node
= nullb
? nullb
->dev
->home_node
: g_home_node
;
1673 set
->cmd_size
= sizeof(struct nullb_cmd
);
1674 set
->flags
= BLK_MQ_F_SHOULD_MERGE
;
1676 set
->flags
|= BLK_MQ_F_NO_SCHED
;
1677 set
->driver_data
= NULL
;
1679 if ((nullb
&& nullb
->dev
->blocking
) || g_blocking
)
1680 set
->flags
|= BLK_MQ_F_BLOCKING
;
1682 return blk_mq_alloc_tag_set(set
);
1685 static int null_validate_conf(struct nullb_device
*dev
)
1687 dev
->blocksize
= round_down(dev
->blocksize
, 512);
1688 dev
->blocksize
= clamp_t(unsigned int, dev
->blocksize
, 512, 4096);
1690 if (dev
->queue_mode
== NULL_Q_MQ
&& dev
->use_per_node_hctx
) {
1691 if (dev
->submit_queues
!= nr_online_nodes
)
1692 dev
->submit_queues
= nr_online_nodes
;
1693 } else if (dev
->submit_queues
> nr_cpu_ids
)
1694 dev
->submit_queues
= nr_cpu_ids
;
1695 else if (dev
->submit_queues
== 0)
1696 dev
->submit_queues
= 1;
1698 dev
->queue_mode
= min_t(unsigned int, dev
->queue_mode
, NULL_Q_MQ
);
1699 dev
->irqmode
= min_t(unsigned int, dev
->irqmode
, NULL_IRQ_TIMER
);
1701 /* Do memory allocation, so set blocking */
1702 if (dev
->memory_backed
)
1703 dev
->blocking
= true;
1704 else /* cache is meaningless */
1705 dev
->cache_size
= 0;
1706 dev
->cache_size
= min_t(unsigned long, ULONG_MAX
/ 1024 / 1024,
1708 dev
->mbps
= min_t(unsigned int, 1024 * 40, dev
->mbps
);
1709 /* can not stop a queue */
1710 if (dev
->queue_mode
== NULL_Q_BIO
)
1714 (!dev
->zone_size
|| !is_power_of_2(dev
->zone_size
))) {
1715 pr_err("zone_size must be power-of-two\n");
1722 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
1723 static bool __null_setup_fault(struct fault_attr
*attr
, char *str
)
1728 if (!setup_fault_attr(attr
, str
))
1736 static bool null_setup_fault(void)
1738 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
1739 if (!__null_setup_fault(&null_timeout_attr
, g_timeout_str
))
1741 if (!__null_setup_fault(&null_requeue_attr
, g_requeue_str
))
1743 if (!__null_setup_fault(&null_init_hctx_attr
, g_init_hctx_str
))
1749 static int null_add_dev(struct nullb_device
*dev
)
1751 struct nullb
*nullb
;
1754 rv
= null_validate_conf(dev
);
1758 nullb
= kzalloc_node(sizeof(*nullb
), GFP_KERNEL
, dev
->home_node
);
1766 spin_lock_init(&nullb
->lock
);
1768 rv
= setup_queues(nullb
);
1770 goto out_free_nullb
;
1772 if (dev
->queue_mode
== NULL_Q_MQ
) {
1774 nullb
->tag_set
= &tag_set
;
1777 nullb
->tag_set
= &nullb
->__tag_set
;
1778 rv
= null_init_tag_set(nullb
, nullb
->tag_set
);
1782 goto out_cleanup_queues
;
1784 if (!null_setup_fault())
1785 goto out_cleanup_queues
;
1787 nullb
->tag_set
->timeout
= 5 * HZ
;
1788 nullb
->q
= blk_mq_init_queue_data(nullb
->tag_set
, nullb
);
1789 if (IS_ERR(nullb
->q
)) {
1791 goto out_cleanup_tags
;
1793 } else if (dev
->queue_mode
== NULL_Q_BIO
) {
1794 nullb
->q
= blk_alloc_queue(null_queue_bio
, dev
->home_node
);
1797 goto out_cleanup_queues
;
1799 rv
= init_driver_queues(nullb
);
1801 goto out_cleanup_blk_queue
;
1805 set_bit(NULLB_DEV_FL_THROTTLED
, &dev
->flags
);
1806 nullb_setup_bwtimer(nullb
);
1809 if (dev
->cache_size
> 0) {
1810 set_bit(NULLB_DEV_FL_CACHE
, &nullb
->dev
->flags
);
1811 blk_queue_write_cache(nullb
->q
, true, true);
1815 rv
= null_init_zoned_dev(dev
, nullb
->q
);
1817 goto out_cleanup_blk_queue
;
1820 nullb
->q
->queuedata
= nullb
;
1821 blk_queue_flag_set(QUEUE_FLAG_NONROT
, nullb
->q
);
1822 blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM
, nullb
->q
);
1825 nullb
->index
= ida_simple_get(&nullb_indexes
, 0, 0, GFP_KERNEL
);
1826 dev
->index
= nullb
->index
;
1827 mutex_unlock(&lock
);
1829 blk_queue_logical_block_size(nullb
->q
, dev
->blocksize
);
1830 blk_queue_physical_block_size(nullb
->q
, dev
->blocksize
);
1832 null_config_discard(nullb
);
1834 sprintf(nullb
->disk_name
, "nullb%d", nullb
->index
);
1836 rv
= null_gendisk_register(nullb
);
1838 goto out_cleanup_zone
;
1841 list_add_tail(&nullb
->list
, &nullb_list
);
1842 mutex_unlock(&lock
);
1846 null_free_zoned_dev(dev
);
1847 out_cleanup_blk_queue
:
1848 blk_cleanup_queue(nullb
->q
);
1850 if (dev
->queue_mode
== NULL_Q_MQ
&& nullb
->tag_set
== &nullb
->__tag_set
)
1851 blk_mq_free_tag_set(nullb
->tag_set
);
1853 cleanup_queues(nullb
);
1861 static int __init
null_init(void)
1865 struct nullb
*nullb
;
1866 struct nullb_device
*dev
;
1868 if (g_bs
> PAGE_SIZE
) {
1869 pr_warn("invalid block size\n");
1870 pr_warn("defaults block size to %lu\n", PAGE_SIZE
);
1874 if (g_home_node
!= NUMA_NO_NODE
&& g_home_node
>= nr_online_nodes
) {
1875 pr_err("invalid home_node value\n");
1876 g_home_node
= NUMA_NO_NODE
;
1879 if (g_queue_mode
== NULL_Q_RQ
) {
1880 pr_err("legacy IO path no longer available\n");
1883 if (g_queue_mode
== NULL_Q_MQ
&& g_use_per_node_hctx
) {
1884 if (g_submit_queues
!= nr_online_nodes
) {
1885 pr_warn("submit_queues param is set to %u.\n",
1887 g_submit_queues
= nr_online_nodes
;
1889 } else if (g_submit_queues
> nr_cpu_ids
)
1890 g_submit_queues
= nr_cpu_ids
;
1891 else if (g_submit_queues
<= 0)
1892 g_submit_queues
= 1;
1894 if (g_queue_mode
== NULL_Q_MQ
&& shared_tags
) {
1895 ret
= null_init_tag_set(NULL
, &tag_set
);
1900 config_group_init(&nullb_subsys
.su_group
);
1901 mutex_init(&nullb_subsys
.su_mutex
);
1903 ret
= configfs_register_subsystem(&nullb_subsys
);
1909 null_major
= register_blkdev(0, "nullb");
1910 if (null_major
< 0) {
1915 for (i
= 0; i
< nr_devices
; i
++) {
1916 dev
= null_alloc_dev();
1921 ret
= null_add_dev(dev
);
1928 pr_info("module loaded\n");
1932 while (!list_empty(&nullb_list
)) {
1933 nullb
= list_entry(nullb_list
.next
, struct nullb
, list
);
1935 null_del_dev(nullb
);
1938 unregister_blkdev(null_major
, "nullb");
1940 configfs_unregister_subsystem(&nullb_subsys
);
1942 if (g_queue_mode
== NULL_Q_MQ
&& shared_tags
)
1943 blk_mq_free_tag_set(&tag_set
);
1947 static void __exit
null_exit(void)
1949 struct nullb
*nullb
;
1951 configfs_unregister_subsystem(&nullb_subsys
);
1953 unregister_blkdev(null_major
, "nullb");
1956 while (!list_empty(&nullb_list
)) {
1957 struct nullb_device
*dev
;
1959 nullb
= list_entry(nullb_list
.next
, struct nullb
, list
);
1961 null_del_dev(nullb
);
1964 mutex_unlock(&lock
);
1966 if (g_queue_mode
== NULL_Q_MQ
&& shared_tags
)
1967 blk_mq_free_tag_set(&tag_set
);
1970 module_init(null_init
);
1971 module_exit(null_exit
);
1973 MODULE_AUTHOR("Jens Axboe <axboe@kernel.dk>");
1974 MODULE_LICENSE("GPL");