linux/drivers/block/null_blk_main.c
Niklas Cassel dc4d137ee3 null_blk: add support for max open/active zone limit for zoned devices
Add support for user space to set a max open zone and a max active zone
limit via configfs. By default, the default values are 0 == no limit.

Call the block layer API functions used for exposing the configured
limits to sysfs.

Add accounting in null_blk_zoned so that these new limits are respected.
Performing an operation that would exceed these limits results in a
standard I/O error.

A max open zone limit exists in the ZBC standard.
While null_blk_zoned is used to test the Zoned Block Device model in
Linux, when it comes to differences between ZBC and ZNS, null_blk_zoned
mostly follows ZBC.

Therefore, implement the manage open zone resources function from ZBC,
but additionally add support for max active zones.
This enables user space not only to test against a device with an open
zone limit, but also to test against a device with an active zone limit.

Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-29 08:12:48 -06:00

2013 lines
48 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* Add configfs and memory store: Kyungchan Koh <kkc6196@fb.com> and
* Shaohua Li <shli@fb.com>
*/
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/sched.h>
#include <linux/fs.h>
#include <linux/init.h>
#include "null_blk.h"
#define PAGE_SECTORS_SHIFT (PAGE_SHIFT - SECTOR_SHIFT)
#define PAGE_SECTORS (1 << PAGE_SECTORS_SHIFT)
#define SECTOR_MASK (PAGE_SECTORS - 1)
#define FREE_BATCH 16
#define TICKS_PER_SEC 50ULL
#define TIMER_INTERVAL (NSEC_PER_SEC / TICKS_PER_SEC)
#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
static DECLARE_FAULT_ATTR(null_timeout_attr);
static DECLARE_FAULT_ATTR(null_requeue_attr);
static DECLARE_FAULT_ATTR(null_init_hctx_attr);
#endif
static inline u64 mb_per_tick(int mbps)
{
return (1 << 20) / TICKS_PER_SEC * ((u64) mbps);
}
/*
* Status flags for nullb_device.
*
* CONFIGURED: Device has been configured and turned on. Cannot reconfigure.
* UP: Device is currently on and visible in userspace.
* THROTTLED: Device is being throttled.
* CACHE: Device is using a write-back cache.
*/
enum nullb_device_flags {
NULLB_DEV_FL_CONFIGURED = 0,
NULLB_DEV_FL_UP = 1,
NULLB_DEV_FL_THROTTLED = 2,
NULLB_DEV_FL_CACHE = 3,
};
#define MAP_SZ ((PAGE_SIZE >> SECTOR_SHIFT) + 2)
/*
* nullb_page is a page in memory for nullb devices.
*
* @page: The page holding the data.
* @bitmap: The bitmap represents which sector in the page has data.
* Each bit represents one block size. For example, sector 8
* will use the 7th bit
* The highest 2 bits of bitmap are for special purpose. LOCK means the cache
* page is being flushing to storage. FREE means the cache page is freed and
* should be skipped from flushing to storage. Please see
* null_make_cache_space
*/
struct nullb_page {
struct page *page;
DECLARE_BITMAP(bitmap, MAP_SZ);
};
#define NULLB_PAGE_LOCK (MAP_SZ - 1)
#define NULLB_PAGE_FREE (MAP_SZ - 2)
static LIST_HEAD(nullb_list);
static struct mutex lock;
static int null_major;
static DEFINE_IDA(nullb_indexes);
static struct blk_mq_tag_set tag_set;
enum {
NULL_IRQ_NONE = 0,
NULL_IRQ_SOFTIRQ = 1,
NULL_IRQ_TIMER = 2,
};
enum {
NULL_Q_BIO = 0,
NULL_Q_RQ = 1,
NULL_Q_MQ = 2,
};
static int g_no_sched;
module_param_named(no_sched, g_no_sched, int, 0444);
MODULE_PARM_DESC(no_sched, "No io scheduler");
static int g_submit_queues = 1;
module_param_named(submit_queues, g_submit_queues, int, 0444);
MODULE_PARM_DESC(submit_queues, "Number of submission queues");
static int g_home_node = NUMA_NO_NODE;
module_param_named(home_node, g_home_node, int, 0444);
MODULE_PARM_DESC(home_node, "Home node for the device");
#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
/*
* For more details about fault injection, please refer to
* Documentation/fault-injection/fault-injection.rst.
*/
static char g_timeout_str[80];
module_param_string(timeout, g_timeout_str, sizeof(g_timeout_str), 0444);
MODULE_PARM_DESC(timeout, "Fault injection. timeout=<interval>,<probability>,<space>,<times>");
static char g_requeue_str[80];
module_param_string(requeue, g_requeue_str, sizeof(g_requeue_str), 0444);
MODULE_PARM_DESC(requeue, "Fault injection. requeue=<interval>,<probability>,<space>,<times>");
static char g_init_hctx_str[80];
module_param_string(init_hctx, g_init_hctx_str, sizeof(g_init_hctx_str), 0444);
MODULE_PARM_DESC(init_hctx, "Fault injection to fail hctx init. init_hctx=<interval>,<probability>,<space>,<times>");
#endif
static int g_queue_mode = NULL_Q_MQ;
static int null_param_store_val(const char *str, int *val, int min, int max)
{
int ret, new_val;
ret = kstrtoint(str, 10, &new_val);
if (ret)
return -EINVAL;
if (new_val < min || new_val > max)
return -EINVAL;
*val = new_val;
return 0;
}
static int null_set_queue_mode(const char *str, const struct kernel_param *kp)
{
return null_param_store_val(str, &g_queue_mode, NULL_Q_BIO, NULL_Q_MQ);
}
static const struct kernel_param_ops null_queue_mode_param_ops = {
.set = null_set_queue_mode,
.get = param_get_int,
};
device_param_cb(queue_mode, &null_queue_mode_param_ops, &g_queue_mode, 0444);
MODULE_PARM_DESC(queue_mode, "Block interface to use (0=bio,1=rq,2=multiqueue)");
static int g_gb = 250;
module_param_named(gb, g_gb, int, 0444);
MODULE_PARM_DESC(gb, "Size in GB");
static int g_bs = 512;
module_param_named(bs, g_bs, int, 0444);
MODULE_PARM_DESC(bs, "Block size (in bytes)");
static unsigned int nr_devices = 1;
module_param(nr_devices, uint, 0444);
MODULE_PARM_DESC(nr_devices, "Number of devices to register");
static bool g_blocking;
module_param_named(blocking, g_blocking, bool, 0444);
MODULE_PARM_DESC(blocking, "Register as a blocking blk-mq driver device");
static bool shared_tags;
module_param(shared_tags, bool, 0444);
MODULE_PARM_DESC(shared_tags, "Share tag set between devices for blk-mq");
static bool g_shared_tag_bitmap;
module_param_named(shared_tag_bitmap, g_shared_tag_bitmap, bool, 0444);
MODULE_PARM_DESC(shared_tag_bitmap, "Use shared tag bitmap for all submission queues for blk-mq");
static int g_irqmode = NULL_IRQ_SOFTIRQ;
static int null_set_irqmode(const char *str, const struct kernel_param *kp)
{
return null_param_store_val(str, &g_irqmode, NULL_IRQ_NONE,
NULL_IRQ_TIMER);
}
static const struct kernel_param_ops null_irqmode_param_ops = {
.set = null_set_irqmode,
.get = param_get_int,
};
device_param_cb(irqmode, &null_irqmode_param_ops, &g_irqmode, 0444);
MODULE_PARM_DESC(irqmode, "IRQ completion handler. 0-none, 1-softirq, 2-timer");
static unsigned long g_completion_nsec = 10000;
module_param_named(completion_nsec, g_completion_nsec, ulong, 0444);
MODULE_PARM_DESC(completion_nsec, "Time in ns to complete a request in hardware. Default: 10,000ns");
static int g_hw_queue_depth = 64;
module_param_named(hw_queue_depth, g_hw_queue_depth, int, 0444);
MODULE_PARM_DESC(hw_queue_depth, "Queue depth for each hardware queue. Default: 64");
static bool g_use_per_node_hctx;
module_param_named(use_per_node_hctx, g_use_per_node_hctx, bool, 0444);
MODULE_PARM_DESC(use_per_node_hctx, "Use per-node allocation for hardware context queues. Default: false");
static bool g_zoned;
module_param_named(zoned, g_zoned, bool, S_IRUGO);
MODULE_PARM_DESC(zoned, "Make device as a host-managed zoned block device. Default: false");
static unsigned long g_zone_size = 256;
module_param_named(zone_size, g_zone_size, ulong, S_IRUGO);
MODULE_PARM_DESC(zone_size, "Zone size in MB when block device is zoned. Must be power-of-two: Default: 256");
static unsigned long g_zone_capacity;
module_param_named(zone_capacity, g_zone_capacity, ulong, 0444);
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");
static unsigned int g_zone_nr_conv;
module_param_named(zone_nr_conv, g_zone_nr_conv, uint, 0444);
MODULE_PARM_DESC(zone_nr_conv, "Number of conventional zones when block device is zoned. Default: 0");
static unsigned int g_zone_max_open;
module_param_named(zone_max_open, g_zone_max_open, uint, 0444);
MODULE_PARM_DESC(zone_max_open, "Maximum number of open zones when block device is zoned. Default: 0 (no limit)");
static unsigned int g_zone_max_active;
module_param_named(zone_max_active, g_zone_max_active, uint, 0444);
MODULE_PARM_DESC(zone_max_active, "Maximum number of active zones when block device is zoned. Default: 0 (no limit)");
static struct nullb_device *null_alloc_dev(void);
static void null_free_dev(struct nullb_device *dev);
static void null_del_dev(struct nullb *nullb);
static int null_add_dev(struct nullb_device *dev);
static void null_free_device_storage(struct nullb_device *dev, bool is_cache);
static inline struct nullb_device *to_nullb_device(struct config_item *item)
{
return item ? container_of(item, struct nullb_device, item) : NULL;
}
static inline ssize_t nullb_device_uint_attr_show(unsigned int val, char *page)
{
return snprintf(page, PAGE_SIZE, "%u\n", val);
}
static inline ssize_t nullb_device_ulong_attr_show(unsigned long val,
char *page)
{
return snprintf(page, PAGE_SIZE, "%lu\n", val);
}
static inline ssize_t nullb_device_bool_attr_show(bool val, char *page)
{
return snprintf(page, PAGE_SIZE, "%u\n", val);
}
static ssize_t nullb_device_uint_attr_store(unsigned int *val,
const char *page, size_t count)
{
unsigned int tmp;
int result;
result = kstrtouint(page, 0, &tmp);
if (result < 0)
return result;
*val = tmp;
return count;
}
static ssize_t nullb_device_ulong_attr_store(unsigned long *val,
const char *page, size_t count)
{
int result;
unsigned long tmp;
result = kstrtoul(page, 0, &tmp);
if (result < 0)
return result;
*val = tmp;
return count;
}
static ssize_t nullb_device_bool_attr_store(bool *val, const char *page,
size_t count)
{
bool tmp;
int result;
result = kstrtobool(page, &tmp);
if (result < 0)
return result;
*val = tmp;
return count;
}
/* The following macro should only be used with TYPE = {uint, ulong, bool}. */
#define NULLB_DEVICE_ATTR(NAME, TYPE, APPLY) \
static ssize_t \
nullb_device_##NAME##_show(struct config_item *item, char *page) \
{ \
return nullb_device_##TYPE##_attr_show( \
to_nullb_device(item)->NAME, page); \
} \
static ssize_t \
nullb_device_##NAME##_store(struct config_item *item, const char *page, \
size_t count) \
{ \
int (*apply_fn)(struct nullb_device *dev, TYPE new_value) = APPLY;\
struct nullb_device *dev = to_nullb_device(item); \
TYPE new_value = 0; \
int ret; \
\
ret = nullb_device_##TYPE##_attr_store(&new_value, page, count);\
if (ret < 0) \
return ret; \
if (apply_fn) \
ret = apply_fn(dev, new_value); \
else if (test_bit(NULLB_DEV_FL_CONFIGURED, &dev->flags)) \
ret = -EBUSY; \
if (ret < 0) \
return ret; \
dev->NAME = new_value; \
return count; \
} \
CONFIGFS_ATTR(nullb_device_, NAME);
static int nullb_apply_submit_queues(struct nullb_device *dev,
unsigned int submit_queues)
{
struct nullb *nullb = dev->nullb;
struct blk_mq_tag_set *set;
if (!nullb)
return 0;
/*
* Make sure that null_init_hctx() does not access nullb->queues[] past
* the end of that array.
*/
if (submit_queues > nr_cpu_ids)
return -EINVAL;
set = nullb->tag_set;
blk_mq_update_nr_hw_queues(set, submit_queues);
return set->nr_hw_queues == submit_queues ? 0 : -ENOMEM;
}
NULLB_DEVICE_ATTR(size, ulong, NULL);
NULLB_DEVICE_ATTR(completion_nsec, ulong, NULL);
NULLB_DEVICE_ATTR(submit_queues, uint, nullb_apply_submit_queues);
NULLB_DEVICE_ATTR(home_node, uint, NULL);
NULLB_DEVICE_ATTR(queue_mode, uint, NULL);
NULLB_DEVICE_ATTR(blocksize, uint, NULL);
NULLB_DEVICE_ATTR(irqmode, uint, NULL);
NULLB_DEVICE_ATTR(hw_queue_depth, uint, NULL);
NULLB_DEVICE_ATTR(index, uint, NULL);
NULLB_DEVICE_ATTR(blocking, bool, NULL);
NULLB_DEVICE_ATTR(use_per_node_hctx, bool, NULL);
NULLB_DEVICE_ATTR(memory_backed, bool, NULL);
NULLB_DEVICE_ATTR(discard, bool, NULL);
NULLB_DEVICE_ATTR(mbps, uint, NULL);
NULLB_DEVICE_ATTR(cache_size, ulong, NULL);
NULLB_DEVICE_ATTR(zoned, bool, NULL);
NULLB_DEVICE_ATTR(zone_size, ulong, NULL);
NULLB_DEVICE_ATTR(zone_capacity, ulong, NULL);
NULLB_DEVICE_ATTR(zone_nr_conv, uint, NULL);
NULLB_DEVICE_ATTR(zone_max_open, uint, NULL);
NULLB_DEVICE_ATTR(zone_max_active, uint, NULL);
static ssize_t nullb_device_power_show(struct config_item *item, char *page)
{
return nullb_device_bool_attr_show(to_nullb_device(item)->power, page);
}
static ssize_t nullb_device_power_store(struct config_item *item,
const char *page, size_t count)
{
struct nullb_device *dev = to_nullb_device(item);
bool newp = false;
ssize_t ret;
ret = nullb_device_bool_attr_store(&newp, page, count);
if (ret < 0)
return ret;
if (!dev->power && newp) {
if (test_and_set_bit(NULLB_DEV_FL_UP, &dev->flags))
return count;
if (null_add_dev(dev)) {
clear_bit(NULLB_DEV_FL_UP, &dev->flags);
return -ENOMEM;
}
set_bit(NULLB_DEV_FL_CONFIGURED, &dev->flags);
dev->power = newp;
} else if (dev->power && !newp) {
if (test_and_clear_bit(NULLB_DEV_FL_UP, &dev->flags)) {
mutex_lock(&lock);
dev->power = newp;
null_del_dev(dev->nullb);
mutex_unlock(&lock);
}
clear_bit(NULLB_DEV_FL_CONFIGURED, &dev->flags);
}
return count;
}
CONFIGFS_ATTR(nullb_device_, power);
static ssize_t nullb_device_badblocks_show(struct config_item *item, char *page)
{
struct nullb_device *t_dev = to_nullb_device(item);
return badblocks_show(&t_dev->badblocks, page, 0);
}
static ssize_t nullb_device_badblocks_store(struct config_item *item,
const char *page, size_t count)
{
struct nullb_device *t_dev = to_nullb_device(item);
char *orig, *buf, *tmp;
u64 start, end;
int ret;
orig = kstrndup(page, count, GFP_KERNEL);
if (!orig)
return -ENOMEM;
buf = strstrip(orig);
ret = -EINVAL;
if (buf[0] != '+' && buf[0] != '-')
goto out;
tmp = strchr(&buf[1], '-');
if (!tmp)
goto out;
*tmp = '\0';
ret = kstrtoull(buf + 1, 0, &start);
if (ret)
goto out;
ret = kstrtoull(tmp + 1, 0, &end);
if (ret)
goto out;
ret = -EINVAL;
if (start > end)
goto out;
/* enable badblocks */
cmpxchg(&t_dev->badblocks.shift, -1, 0);
if (buf[0] == '+')
ret = badblocks_set(&t_dev->badblocks, start,
end - start + 1, 1);
else
ret = badblocks_clear(&t_dev->badblocks, start,
end - start + 1);
if (ret == 0)
ret = count;
out:
kfree(orig);
return ret;
}
CONFIGFS_ATTR(nullb_device_, badblocks);
static struct configfs_attribute *nullb_device_attrs[] = {
&nullb_device_attr_size,
&nullb_device_attr_completion_nsec,
&nullb_device_attr_submit_queues,
&nullb_device_attr_home_node,
&nullb_device_attr_queue_mode,
&nullb_device_attr_blocksize,
&nullb_device_attr_irqmode,
&nullb_device_attr_hw_queue_depth,
&nullb_device_attr_index,
&nullb_device_attr_blocking,
&nullb_device_attr_use_per_node_hctx,
&nullb_device_attr_power,
&nullb_device_attr_memory_backed,
&nullb_device_attr_discard,
&nullb_device_attr_mbps,
&nullb_device_attr_cache_size,
&nullb_device_attr_badblocks,
&nullb_device_attr_zoned,
&nullb_device_attr_zone_size,
&nullb_device_attr_zone_capacity,
&nullb_device_attr_zone_nr_conv,
&nullb_device_attr_zone_max_open,
&nullb_device_attr_zone_max_active,
NULL,
};
static void nullb_device_release(struct config_item *item)
{
struct nullb_device *dev = to_nullb_device(item);
null_free_device_storage(dev, false);
null_free_dev(dev);
}
static struct configfs_item_operations nullb_device_ops = {
.release = nullb_device_release,
};
static const struct config_item_type nullb_device_type = {
.ct_item_ops = &nullb_device_ops,
.ct_attrs = nullb_device_attrs,
.ct_owner = THIS_MODULE,
};
static struct
config_item *nullb_group_make_item(struct config_group *group, const char *name)
{
struct nullb_device *dev;
dev = null_alloc_dev();
if (!dev)
return ERR_PTR(-ENOMEM);
config_item_init_type_name(&dev->item, name, &nullb_device_type);
return &dev->item;
}
static void
nullb_group_drop_item(struct config_group *group, struct config_item *item)
{
struct nullb_device *dev = to_nullb_device(item);
if (test_and_clear_bit(NULLB_DEV_FL_UP, &dev->flags)) {
mutex_lock(&lock);
dev->power = false;
null_del_dev(dev->nullb);
mutex_unlock(&lock);
}
config_item_put(item);
}
static ssize_t memb_group_features_show(struct config_item *item, char *page)
{
return snprintf(page, PAGE_SIZE,
"memory_backed,discard,bandwidth,cache,badblocks,zoned,zone_size,zone_capacity,zone_nr_conv,zone_max_open,zone_max_active\n");
}
CONFIGFS_ATTR_RO(memb_group_, features);
static struct configfs_attribute *nullb_group_attrs[] = {
&memb_group_attr_features,
NULL,
};
static struct configfs_group_operations nullb_group_ops = {
.make_item = nullb_group_make_item,
.drop_item = nullb_group_drop_item,
};
static const struct config_item_type nullb_group_type = {
.ct_group_ops = &nullb_group_ops,
.ct_attrs = nullb_group_attrs,
.ct_owner = THIS_MODULE,
};
static struct configfs_subsystem nullb_subsys = {
.su_group = {
.cg_item = {
.ci_namebuf = "nullb",
.ci_type = &nullb_group_type,
},
},
};
static inline int null_cache_active(struct nullb *nullb)
{
return test_bit(NULLB_DEV_FL_CACHE, &nullb->dev->flags);
}
static struct nullb_device *null_alloc_dev(void)
{
struct nullb_device *dev;
dev = kzalloc(sizeof(*dev), GFP_KERNEL);
if (!dev)
return NULL;
INIT_RADIX_TREE(&dev->data, GFP_ATOMIC);
INIT_RADIX_TREE(&dev->cache, GFP_ATOMIC);
if (badblocks_init(&dev->badblocks, 0)) {
kfree(dev);
return NULL;
}
dev->size = g_gb * 1024;
dev->completion_nsec = g_completion_nsec;
dev->submit_queues = g_submit_queues;
dev->home_node = g_home_node;
dev->queue_mode = g_queue_mode;
dev->blocksize = g_bs;
dev->irqmode = g_irqmode;
dev->hw_queue_depth = g_hw_queue_depth;
dev->blocking = g_blocking;
dev->use_per_node_hctx = g_use_per_node_hctx;
dev->zoned = g_zoned;
dev->zone_size = g_zone_size;
dev->zone_capacity = g_zone_capacity;
dev->zone_nr_conv = g_zone_nr_conv;
dev->zone_max_open = g_zone_max_open;
dev->zone_max_active = g_zone_max_active;
return dev;
}
static void null_free_dev(struct nullb_device *dev)
{
if (!dev)
return;
null_free_zoned_dev(dev);
badblocks_exit(&dev->badblocks);
kfree(dev);
}
static void put_tag(struct nullb_queue *nq, unsigned int tag)
{
clear_bit_unlock(tag, nq->tag_map);
if (waitqueue_active(&nq->wait))
wake_up(&nq->wait);
}
static unsigned int get_tag(struct nullb_queue *nq)
{
unsigned int tag;
do {
tag = find_first_zero_bit(nq->tag_map, nq->queue_depth);
if (tag >= nq->queue_depth)
return -1U;
} while (test_and_set_bit_lock(tag, nq->tag_map));
return tag;
}
static void free_cmd(struct nullb_cmd *cmd)
{
put_tag(cmd->nq, cmd->tag);
}
static enum hrtimer_restart null_cmd_timer_expired(struct hrtimer *timer);
static struct nullb_cmd *__alloc_cmd(struct nullb_queue *nq)
{
struct nullb_cmd *cmd;
unsigned int tag;
tag = get_tag(nq);
if (tag != -1U) {
cmd = &nq->cmds[tag];
cmd->tag = tag;
cmd->error = BLK_STS_OK;
cmd->nq = nq;
if (nq->dev->irqmode == NULL_IRQ_TIMER) {
hrtimer_init(&cmd->timer, CLOCK_MONOTONIC,
HRTIMER_MODE_REL);
cmd->timer.function = null_cmd_timer_expired;
}
return cmd;
}
return NULL;
}
static struct nullb_cmd *alloc_cmd(struct nullb_queue *nq, int can_wait)
{
struct nullb_cmd *cmd;
DEFINE_WAIT(wait);
cmd = __alloc_cmd(nq);
if (cmd || !can_wait)
return cmd;
do {
prepare_to_wait(&nq->wait, &wait, TASK_UNINTERRUPTIBLE);
cmd = __alloc_cmd(nq);
if (cmd)
break;
io_schedule();
} while (1);
finish_wait(&nq->wait, &wait);
return cmd;
}
static void end_cmd(struct nullb_cmd *cmd)
{
int queue_mode = cmd->nq->dev->queue_mode;
switch (queue_mode) {
case NULL_Q_MQ:
blk_mq_end_request(cmd->rq, cmd->error);
return;
case NULL_Q_BIO:
cmd->bio->bi_status = cmd->error;
bio_endio(cmd->bio);
break;
}
free_cmd(cmd);
}
static enum hrtimer_restart null_cmd_timer_expired(struct hrtimer *timer)
{
end_cmd(container_of(timer, struct nullb_cmd, timer));
return HRTIMER_NORESTART;
}
static void null_cmd_end_timer(struct nullb_cmd *cmd)
{
ktime_t kt = cmd->nq->dev->completion_nsec;
hrtimer_start(&cmd->timer, kt, HRTIMER_MODE_REL);
}
static void null_complete_rq(struct request *rq)
{
end_cmd(blk_mq_rq_to_pdu(rq));
}
static struct nullb_page *null_alloc_page(gfp_t gfp_flags)
{
struct nullb_page *t_page;
t_page = kmalloc(sizeof(struct nullb_page), gfp_flags);
if (!t_page)
goto out;
t_page->page = alloc_pages(gfp_flags, 0);
if (!t_page->page)
goto out_freepage;
memset(t_page->bitmap, 0, sizeof(t_page->bitmap));
return t_page;
out_freepage:
kfree(t_page);
out:
return NULL;
}
static void null_free_page(struct nullb_page *t_page)
{
__set_bit(NULLB_PAGE_FREE, t_page->bitmap);
if (test_bit(NULLB_PAGE_LOCK, t_page->bitmap))
return;
__free_page(t_page->page);
kfree(t_page);
}
static bool null_page_empty(struct nullb_page *page)
{
int size = MAP_SZ - 2;
return find_first_bit(page->bitmap, size) == size;
}
static void null_free_sector(struct nullb *nullb, sector_t sector,
bool is_cache)
{
unsigned int sector_bit;
u64 idx;
struct nullb_page *t_page, *ret;
struct radix_tree_root *root;
root = is_cache ? &nullb->dev->cache : &nullb->dev->data;
idx = sector >> PAGE_SECTORS_SHIFT;
sector_bit = (sector & SECTOR_MASK);
t_page = radix_tree_lookup(root, idx);
if (t_page) {
__clear_bit(sector_bit, t_page->bitmap);
if (null_page_empty(t_page)) {
ret = radix_tree_delete_item(root, idx, t_page);
WARN_ON(ret != t_page);
null_free_page(ret);
if (is_cache)
nullb->dev->curr_cache -= PAGE_SIZE;
}
}
}
static struct nullb_page *null_radix_tree_insert(struct nullb *nullb, u64 idx,
struct nullb_page *t_page, bool is_cache)
{
struct radix_tree_root *root;
root = is_cache ? &nullb->dev->cache : &nullb->dev->data;
if (radix_tree_insert(root, idx, t_page)) {
null_free_page(t_page);
t_page = radix_tree_lookup(root, idx);
WARN_ON(!t_page || t_page->page->index != idx);
} else if (is_cache)
nullb->dev->curr_cache += PAGE_SIZE;
return t_page;
}
static void null_free_device_storage(struct nullb_device *dev, bool is_cache)
{
unsigned long pos = 0;
int nr_pages;
struct nullb_page *ret, *t_pages[FREE_BATCH];
struct radix_tree_root *root;
root = is_cache ? &dev->cache : &dev->data;
do {
int i;
nr_pages = radix_tree_gang_lookup(root,
(void **)t_pages, pos, FREE_BATCH);
for (i = 0; i < nr_pages; i++) {
pos = t_pages[i]->page->index;
ret = radix_tree_delete_item(root, pos, t_pages[i]);
WARN_ON(ret != t_pages[i]);
null_free_page(ret);
}
pos++;
} while (nr_pages == FREE_BATCH);
if (is_cache)
dev->curr_cache = 0;
}
static struct nullb_page *__null_lookup_page(struct nullb *nullb,
sector_t sector, bool for_write, bool is_cache)
{
unsigned int sector_bit;
u64 idx;
struct nullb_page *t_page;
struct radix_tree_root *root;
idx = sector >> PAGE_SECTORS_SHIFT;
sector_bit = (sector & SECTOR_MASK);
root = is_cache ? &nullb->dev->cache : &nullb->dev->data;
t_page = radix_tree_lookup(root, idx);
WARN_ON(t_page && t_page->page->index != idx);
if (t_page && (for_write || test_bit(sector_bit, t_page->bitmap)))
return t_page;
return NULL;
}
static struct nullb_page *null_lookup_page(struct nullb *nullb,
sector_t sector, bool for_write, bool ignore_cache)
{
struct nullb_page *page = NULL;
if (!ignore_cache)
page = __null_lookup_page(nullb, sector, for_write, true);
if (page)
return page;
return __null_lookup_page(nullb, sector, for_write, false);
}
static struct nullb_page *null_insert_page(struct nullb *nullb,
sector_t sector, bool ignore_cache)
__releases(&nullb->lock)
__acquires(&nullb->lock)
{
u64 idx;
struct nullb_page *t_page;
t_page = null_lookup_page(nullb, sector, true, ignore_cache);
if (t_page)
return t_page;
spin_unlock_irq(&nullb->lock);
t_page = null_alloc_page(GFP_NOIO);
if (!t_page)
goto out_lock;
if (radix_tree_preload(GFP_NOIO))
goto out_freepage;
spin_lock_irq(&nullb->lock);
idx = sector >> PAGE_SECTORS_SHIFT;
t_page->page->index = idx;
t_page = null_radix_tree_insert(nullb, idx, t_page, !ignore_cache);
radix_tree_preload_end();
return t_page;
out_freepage:
null_free_page(t_page);
out_lock:
spin_lock_irq(&nullb->lock);
return null_lookup_page(nullb, sector, true, ignore_cache);
}
static int null_flush_cache_page(struct nullb *nullb, struct nullb_page *c_page)
{
int i;
unsigned int offset;
u64 idx;
struct nullb_page *t_page, *ret;
void *dst, *src;
idx = c_page->page->index;
t_page = null_insert_page(nullb, idx << PAGE_SECTORS_SHIFT, true);
__clear_bit(NULLB_PAGE_LOCK, c_page->bitmap);
if (test_bit(NULLB_PAGE_FREE, c_page->bitmap)) {
null_free_page(c_page);
if (t_page && null_page_empty(t_page)) {
ret = radix_tree_delete_item(&nullb->dev->data,
idx, t_page);
null_free_page(t_page);
}
return 0;
}
if (!t_page)
return -ENOMEM;
src = kmap_atomic(c_page->page);
dst = kmap_atomic(t_page->page);
for (i = 0; i < PAGE_SECTORS;
i += (nullb->dev->blocksize >> SECTOR_SHIFT)) {
if (test_bit(i, c_page->bitmap)) {
offset = (i << SECTOR_SHIFT);
memcpy(dst + offset, src + offset,
nullb->dev->blocksize);
__set_bit(i, t_page->bitmap);
}
}
kunmap_atomic(dst);
kunmap_atomic(src);
ret = radix_tree_delete_item(&nullb->dev->cache, idx, c_page);
null_free_page(ret);
nullb->dev->curr_cache -= PAGE_SIZE;
return 0;
}
static int null_make_cache_space(struct nullb *nullb, unsigned long n)
{
int i, err, nr_pages;
struct nullb_page *c_pages[FREE_BATCH];
unsigned long flushed = 0, one_round;
again:
if ((nullb->dev->cache_size * 1024 * 1024) >
nullb->dev->curr_cache + n || nullb->dev->curr_cache == 0)
return 0;
nr_pages = radix_tree_gang_lookup(&nullb->dev->cache,
(void **)c_pages, nullb->cache_flush_pos, FREE_BATCH);
/*
* nullb_flush_cache_page could unlock before using the c_pages. To
* avoid race, we don't allow page free
*/
for (i = 0; i < nr_pages; i++) {
nullb->cache_flush_pos = c_pages[i]->page->index;
/*
* We found the page which is being flushed to disk by other
* threads
*/
if (test_bit(NULLB_PAGE_LOCK, c_pages[i]->bitmap))
c_pages[i] = NULL;
else
__set_bit(NULLB_PAGE_LOCK, c_pages[i]->bitmap);
}
one_round = 0;
for (i = 0; i < nr_pages; i++) {
if (c_pages[i] == NULL)
continue;
err = null_flush_cache_page(nullb, c_pages[i]);
if (err)
return err;
one_round++;
}
flushed += one_round << PAGE_SHIFT;
if (n > flushed) {
if (nr_pages == 0)
nullb->cache_flush_pos = 0;
if (one_round == 0) {
/* give other threads a chance */
spin_unlock_irq(&nullb->lock);
spin_lock_irq(&nullb->lock);
}
goto again;
}
return 0;
}
static int copy_to_nullb(struct nullb *nullb, struct page *source,
unsigned int off, sector_t sector, size_t n, bool is_fua)
{
size_t temp, count = 0;
unsigned int offset;
struct nullb_page *t_page;
void *dst, *src;
while (count < n) {
temp = min_t(size_t, nullb->dev->blocksize, n - count);
if (null_cache_active(nullb) && !is_fua)
null_make_cache_space(nullb, PAGE_SIZE);
offset = (sector & SECTOR_MASK) << SECTOR_SHIFT;
t_page = null_insert_page(nullb, sector,
!null_cache_active(nullb) || is_fua);
if (!t_page)
return -ENOSPC;
src = kmap_atomic(source);
dst = kmap_atomic(t_page->page);
memcpy(dst + offset, src + off + count, temp);
kunmap_atomic(dst);
kunmap_atomic(src);
__set_bit(sector & SECTOR_MASK, t_page->bitmap);
if (is_fua)
null_free_sector(nullb, sector, true);
count += temp;
sector += temp >> SECTOR_SHIFT;
}
return 0;
}
static int copy_from_nullb(struct nullb *nullb, struct page *dest,
unsigned int off, sector_t sector, size_t n)
{
size_t temp, count = 0;
unsigned int offset;
struct nullb_page *t_page;
void *dst, *src;
while (count < n) {
temp = min_t(size_t, nullb->dev->blocksize, n - count);
offset = (sector & SECTOR_MASK) << SECTOR_SHIFT;
t_page = null_lookup_page(nullb, sector, false,
!null_cache_active(nullb));
dst = kmap_atomic(dest);
if (!t_page) {
memset(dst + off + count, 0, temp);
goto next;
}
src = kmap_atomic(t_page->page);
memcpy(dst + off + count, src + offset, temp);
kunmap_atomic(src);
next:
kunmap_atomic(dst);
count += temp;
sector += temp >> SECTOR_SHIFT;
}
return 0;
}
static void nullb_fill_pattern(struct nullb *nullb, struct page *page,
unsigned int len, unsigned int off)
{
void *dst;
dst = kmap_atomic(page);
memset(dst + off, 0xFF, len);
kunmap_atomic(dst);
}
static void null_handle_discard(struct nullb *nullb, sector_t sector, size_t n)
{
size_t temp;
spin_lock_irq(&nullb->lock);
while (n > 0) {
temp = min_t(size_t, n, nullb->dev->blocksize);
null_free_sector(nullb, sector, false);
if (null_cache_active(nullb))
null_free_sector(nullb, sector, true);
sector += temp >> SECTOR_SHIFT;
n -= temp;
}
spin_unlock_irq(&nullb->lock);
}
static int null_handle_flush(struct nullb *nullb)
{
int err;
if (!null_cache_active(nullb))
return 0;
spin_lock_irq(&nullb->lock);
while (true) {
err = null_make_cache_space(nullb,
nullb->dev->cache_size * 1024 * 1024);
if (err || nullb->dev->curr_cache == 0)
break;
}
WARN_ON(!radix_tree_empty(&nullb->dev->cache));
spin_unlock_irq(&nullb->lock);
return err;
}
static int null_transfer(struct nullb *nullb, struct page *page,
unsigned int len, unsigned int off, bool is_write, sector_t sector,
bool is_fua)
{
struct nullb_device *dev = nullb->dev;
unsigned int valid_len = len;
int err = 0;
if (!is_write) {
if (dev->zoned)
valid_len = null_zone_valid_read_len(nullb,
sector, len);
if (valid_len) {
err = copy_from_nullb(nullb, page, off,
sector, valid_len);
off += valid_len;
len -= valid_len;
}
if (len)
nullb_fill_pattern(nullb, page, len, off);
flush_dcache_page(page);
} else {
flush_dcache_page(page);
err = copy_to_nullb(nullb, page, off, sector, len, is_fua);
}
return err;
}
static int null_handle_rq(struct nullb_cmd *cmd)
{
struct request *rq = cmd->rq;
struct nullb *nullb = cmd->nq->dev->nullb;
int err;
unsigned int len;
sector_t sector;
struct req_iterator iter;
struct bio_vec bvec;
sector = blk_rq_pos(rq);
if (req_op(rq) == REQ_OP_DISCARD) {
null_handle_discard(nullb, sector, blk_rq_bytes(rq));
return 0;
}
spin_lock_irq(&nullb->lock);
rq_for_each_segment(bvec, rq, iter) {
len = bvec.bv_len;
err = null_transfer(nullb, bvec.bv_page, len, bvec.bv_offset,
op_is_write(req_op(rq)), sector,
rq->cmd_flags & REQ_FUA);
if (err) {
spin_unlock_irq(&nullb->lock);
return err;
}
sector += len >> SECTOR_SHIFT;
}
spin_unlock_irq(&nullb->lock);
return 0;
}
static int null_handle_bio(struct nullb_cmd *cmd)
{
struct bio *bio = cmd->bio;
struct nullb *nullb = cmd->nq->dev->nullb;
int err;
unsigned int len;
sector_t sector;
struct bio_vec bvec;
struct bvec_iter iter;
sector = bio->bi_iter.bi_sector;
if (bio_op(bio) == REQ_OP_DISCARD) {
null_handle_discard(nullb, sector,
bio_sectors(bio) << SECTOR_SHIFT);
return 0;
}
spin_lock_irq(&nullb->lock);
bio_for_each_segment(bvec, bio, iter) {
len = bvec.bv_len;
err = null_transfer(nullb, bvec.bv_page, len, bvec.bv_offset,
op_is_write(bio_op(bio)), sector,
bio->bi_opf & REQ_FUA);
if (err) {
spin_unlock_irq(&nullb->lock);
return err;
}
sector += len >> SECTOR_SHIFT;
}
spin_unlock_irq(&nullb->lock);
return 0;
}
static void null_stop_queue(struct nullb *nullb)
{
struct request_queue *q = nullb->q;
if (nullb->dev->queue_mode == NULL_Q_MQ)
blk_mq_stop_hw_queues(q);
}
static void null_restart_queue_async(struct nullb *nullb)
{
struct request_queue *q = nullb->q;
if (nullb->dev->queue_mode == NULL_Q_MQ)
blk_mq_start_stopped_hw_queues(q, true);
}
static inline blk_status_t null_handle_throttled(struct nullb_cmd *cmd)
{
struct nullb_device *dev = cmd->nq->dev;
struct nullb *nullb = dev->nullb;
blk_status_t sts = BLK_STS_OK;
struct request *rq = cmd->rq;
if (!hrtimer_active(&nullb->bw_timer))
hrtimer_restart(&nullb->bw_timer);
if (atomic_long_sub_return(blk_rq_bytes(rq), &nullb->cur_bytes) < 0) {
null_stop_queue(nullb);
/* race with timer */
if (atomic_long_read(&nullb->cur_bytes) > 0)
null_restart_queue_async(nullb);
/* requeue request */
sts = BLK_STS_DEV_RESOURCE;
}
return sts;
}
static inline blk_status_t null_handle_badblocks(struct nullb_cmd *cmd,
sector_t sector,
sector_t nr_sectors)
{
struct badblocks *bb = &cmd->nq->dev->badblocks;
sector_t first_bad;
int bad_sectors;
if (badblocks_check(bb, sector, nr_sectors, &first_bad, &bad_sectors))
return BLK_STS_IOERR;
return BLK_STS_OK;
}
static inline blk_status_t null_handle_memory_backed(struct nullb_cmd *cmd,
enum req_opf op)
{
struct nullb_device *dev = cmd->nq->dev;
int err;
if (dev->queue_mode == NULL_Q_BIO)
err = null_handle_bio(cmd);
else
err = null_handle_rq(cmd);
return errno_to_blk_status(err);
}
static void nullb_zero_read_cmd_buffer(struct nullb_cmd *cmd)
{
struct nullb_device *dev = cmd->nq->dev;
struct bio *bio;
if (dev->memory_backed)
return;
if (dev->queue_mode == NULL_Q_BIO && bio_op(cmd->bio) == REQ_OP_READ) {
zero_fill_bio(cmd->bio);
} else if (req_op(cmd->rq) == REQ_OP_READ) {
__rq_for_each_bio(bio, cmd->rq)
zero_fill_bio(bio);
}
}
static inline void nullb_complete_cmd(struct nullb_cmd *cmd)
{
/*
* Since root privileges are required to configure the null_blk
* driver, it is fine that this driver does not initialize the
* data buffers of read commands. Zero-initialize these buffers
* anyway if KMSAN is enabled to prevent that KMSAN complains
* about null_blk not initializing read data buffers.
*/
if (IS_ENABLED(CONFIG_KMSAN))
nullb_zero_read_cmd_buffer(cmd);
/* Complete IO by inline, softirq or timer */
switch (cmd->nq->dev->irqmode) {
case NULL_IRQ_SOFTIRQ:
switch (cmd->nq->dev->queue_mode) {
case NULL_Q_MQ:
if (likely(!blk_should_fake_timeout(cmd->rq->q)))
blk_mq_complete_request(cmd->rq);
break;
case NULL_Q_BIO:
/*
* XXX: no proper submitting cpu information available.
*/
end_cmd(cmd);
break;
}
break;
case NULL_IRQ_NONE:
end_cmd(cmd);
break;
case NULL_IRQ_TIMER:
null_cmd_end_timer(cmd);
break;
}
}
blk_status_t null_process_cmd(struct nullb_cmd *cmd,
enum req_opf op, sector_t sector,
unsigned int nr_sectors)
{
struct nullb_device *dev = cmd->nq->dev;
blk_status_t ret;
if (dev->badblocks.shift != -1) {
ret = null_handle_badblocks(cmd, sector, nr_sectors);
if (ret != BLK_STS_OK)
return ret;
}
if (dev->memory_backed)
return null_handle_memory_backed(cmd, op);
return BLK_STS_OK;
}
static blk_status_t null_handle_cmd(struct nullb_cmd *cmd, sector_t sector,
sector_t nr_sectors, enum req_opf op)
{
struct nullb_device *dev = cmd->nq->dev;
struct nullb *nullb = dev->nullb;
blk_status_t sts;
if (test_bit(NULLB_DEV_FL_THROTTLED, &dev->flags)) {
sts = null_handle_throttled(cmd);
if (sts != BLK_STS_OK)
return sts;
}
if (op == REQ_OP_FLUSH) {
cmd->error = errno_to_blk_status(null_handle_flush(nullb));
goto out;
}
if (dev->zoned)
cmd->error = null_process_zoned_cmd(cmd, op,
sector, nr_sectors);
else
cmd->error = null_process_cmd(cmd, op, sector, nr_sectors);
out:
nullb_complete_cmd(cmd);
return BLK_STS_OK;
}
static enum hrtimer_restart nullb_bwtimer_fn(struct hrtimer *timer)
{
struct nullb *nullb = container_of(timer, struct nullb, bw_timer);
ktime_t timer_interval = ktime_set(0, TIMER_INTERVAL);
unsigned int mbps = nullb->dev->mbps;
if (atomic_long_read(&nullb->cur_bytes) == mb_per_tick(mbps))
return HRTIMER_NORESTART;
atomic_long_set(&nullb->cur_bytes, mb_per_tick(mbps));
null_restart_queue_async(nullb);
hrtimer_forward_now(&nullb->bw_timer, timer_interval);
return HRTIMER_RESTART;
}
static void nullb_setup_bwtimer(struct nullb *nullb)
{
ktime_t timer_interval = ktime_set(0, TIMER_INTERVAL);
hrtimer_init(&nullb->bw_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
nullb->bw_timer.function = nullb_bwtimer_fn;
atomic_long_set(&nullb->cur_bytes, mb_per_tick(nullb->dev->mbps));
hrtimer_start(&nullb->bw_timer, timer_interval, HRTIMER_MODE_REL);
}
static struct nullb_queue *nullb_to_queue(struct nullb *nullb)
{
int index = 0;
if (nullb->nr_queues != 1)
index = raw_smp_processor_id() / ((nr_cpu_ids + nullb->nr_queues - 1) / nullb->nr_queues);
return &nullb->queues[index];
}
static blk_qc_t null_submit_bio(struct bio *bio)
{
sector_t sector = bio->bi_iter.bi_sector;
sector_t nr_sectors = bio_sectors(bio);
struct nullb *nullb = bio->bi_disk->private_data;
struct nullb_queue *nq = nullb_to_queue(nullb);
struct nullb_cmd *cmd;
cmd = alloc_cmd(nq, 1);
cmd->bio = bio;
null_handle_cmd(cmd, sector, nr_sectors, bio_op(bio));
return BLK_QC_T_NONE;
}
static bool should_timeout_request(struct request *rq)
{
#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
if (g_timeout_str[0])
return should_fail(&null_timeout_attr, 1);
#endif
return false;
}
static bool should_requeue_request(struct request *rq)
{
#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
if (g_requeue_str[0])
return should_fail(&null_requeue_attr, 1);
#endif
return false;
}
static enum blk_eh_timer_return null_timeout_rq(struct request *rq, bool res)
{
pr_info("rq %p timed out\n", rq);
blk_mq_complete_request(rq);
return BLK_EH_DONE;
}
static blk_status_t null_queue_rq(struct blk_mq_hw_ctx *hctx,
const struct blk_mq_queue_data *bd)
{
struct nullb_cmd *cmd = blk_mq_rq_to_pdu(bd->rq);
struct nullb_queue *nq = hctx->driver_data;
sector_t nr_sectors = blk_rq_sectors(bd->rq);
sector_t sector = blk_rq_pos(bd->rq);
might_sleep_if(hctx->flags & BLK_MQ_F_BLOCKING);
if (nq->dev->irqmode == NULL_IRQ_TIMER) {
hrtimer_init(&cmd->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
cmd->timer.function = null_cmd_timer_expired;
}
cmd->rq = bd->rq;
cmd->error = BLK_STS_OK;
cmd->nq = nq;
blk_mq_start_request(bd->rq);
if (should_requeue_request(bd->rq)) {
/*
* Alternate between hitting the core BUSY path, and the
* driver driven requeue path
*/
nq->requeue_selection++;
if (nq->requeue_selection & 1)
return BLK_STS_RESOURCE;
else {
blk_mq_requeue_request(bd->rq, true);
return BLK_STS_OK;
}
}
if (should_timeout_request(bd->rq))
return BLK_STS_OK;
return null_handle_cmd(cmd, sector, nr_sectors, req_op(bd->rq));
}
static void cleanup_queue(struct nullb_queue *nq)
{
kfree(nq->tag_map);
kfree(nq->cmds);
}
static void cleanup_queues(struct nullb *nullb)
{
int i;
for (i = 0; i < nullb->nr_queues; i++)
cleanup_queue(&nullb->queues[i]);
kfree(nullb->queues);
}
static void null_exit_hctx(struct blk_mq_hw_ctx *hctx, unsigned int hctx_idx)
{
struct nullb_queue *nq = hctx->driver_data;
struct nullb *nullb = nq->dev->nullb;
nullb->nr_queues--;
}
static void null_init_queue(struct nullb *nullb, struct nullb_queue *nq)
{
init_waitqueue_head(&nq->wait);
nq->queue_depth = nullb->queue_depth;
nq->dev = nullb->dev;
}
static int null_init_hctx(struct blk_mq_hw_ctx *hctx, void *driver_data,
unsigned int hctx_idx)
{
struct nullb *nullb = hctx->queue->queuedata;
struct nullb_queue *nq;
#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
if (g_init_hctx_str[0] && should_fail(&null_init_hctx_attr, 1))
return -EFAULT;
#endif
nq = &nullb->queues[hctx_idx];
hctx->driver_data = nq;
null_init_queue(nullb, nq);
nullb->nr_queues++;
return 0;
}
static const struct blk_mq_ops null_mq_ops = {
.queue_rq = null_queue_rq,
.complete = null_complete_rq,
.timeout = null_timeout_rq,
.init_hctx = null_init_hctx,
.exit_hctx = null_exit_hctx,
};
static void null_del_dev(struct nullb *nullb)
{
struct nullb_device *dev;
if (!nullb)
return;
dev = nullb->dev;
ida_simple_remove(&nullb_indexes, nullb->index);
list_del_init(&nullb->list);
del_gendisk(nullb->disk);
if (test_bit(NULLB_DEV_FL_THROTTLED, &nullb->dev->flags)) {
hrtimer_cancel(&nullb->bw_timer);
atomic_long_set(&nullb->cur_bytes, LONG_MAX);
null_restart_queue_async(nullb);
}
blk_cleanup_queue(nullb->q);
if (dev->queue_mode == NULL_Q_MQ &&
nullb->tag_set == &nullb->__tag_set)
blk_mq_free_tag_set(nullb->tag_set);
put_disk(nullb->disk);
cleanup_queues(nullb);
if (null_cache_active(nullb))
null_free_device_storage(nullb->dev, true);
kfree(nullb);
dev->nullb = NULL;
}
static void null_config_discard(struct nullb *nullb)
{
if (nullb->dev->discard == false)
return;
if (nullb->dev->zoned) {
nullb->dev->discard = false;
pr_info("discard option is ignored in zoned mode\n");
return;
}
nullb->q->limits.discard_granularity = nullb->dev->blocksize;
nullb->q->limits.discard_alignment = nullb->dev->blocksize;
blk_queue_max_discard_sectors(nullb->q, UINT_MAX >> 9);
blk_queue_flag_set(QUEUE_FLAG_DISCARD, nullb->q);
}
static const struct block_device_operations null_bio_ops = {
.owner = THIS_MODULE,
.submit_bio = null_submit_bio,
.report_zones = null_report_zones,
};
static const struct block_device_operations null_rq_ops = {
.owner = THIS_MODULE,
.report_zones = null_report_zones,
};
static int setup_commands(struct nullb_queue *nq)
{
struct nullb_cmd *cmd;
int i, tag_size;
nq->cmds = kcalloc(nq->queue_depth, sizeof(*cmd), GFP_KERNEL);
if (!nq->cmds)
return -ENOMEM;
tag_size = ALIGN(nq->queue_depth, BITS_PER_LONG) / BITS_PER_LONG;
nq->tag_map = kcalloc(tag_size, sizeof(unsigned long), GFP_KERNEL);
if (!nq->tag_map) {
kfree(nq->cmds);
return -ENOMEM;
}
for (i = 0; i < nq->queue_depth; i++) {
cmd = &nq->cmds[i];
cmd->tag = -1U;
}
return 0;
}
static int setup_queues(struct nullb *nullb)
{
nullb->queues = kcalloc(nr_cpu_ids, sizeof(struct nullb_queue),
GFP_KERNEL);
if (!nullb->queues)
return -ENOMEM;
nullb->queue_depth = nullb->dev->hw_queue_depth;
return 0;
}
static int init_driver_queues(struct nullb *nullb)
{
struct nullb_queue *nq;
int i, ret = 0;
for (i = 0; i < nullb->dev->submit_queues; i++) {
nq = &nullb->queues[i];
null_init_queue(nullb, nq);
ret = setup_commands(nq);
if (ret)
return ret;
nullb->nr_queues++;
}
return 0;
}
static int null_gendisk_register(struct nullb *nullb)
{
sector_t size = ((sector_t)nullb->dev->size * SZ_1M) >> SECTOR_SHIFT;
struct gendisk *disk;
disk = nullb->disk = alloc_disk_node(1, nullb->dev->home_node);
if (!disk)
return -ENOMEM;
set_capacity(disk, size);
disk->flags |= GENHD_FL_EXT_DEVT | GENHD_FL_SUPPRESS_PARTITION_INFO;
disk->major = null_major;
disk->first_minor = nullb->index;
if (queue_is_mq(nullb->q))
disk->fops = &null_rq_ops;
else
disk->fops = &null_bio_ops;
disk->private_data = nullb;
disk->queue = nullb->q;
strncpy(disk->disk_name, nullb->disk_name, DISK_NAME_LEN);
if (nullb->dev->zoned) {
int ret = null_register_zoned_dev(nullb);
if (ret)
return ret;
}
add_disk(disk);
return 0;
}
static int null_init_tag_set(struct nullb *nullb, struct blk_mq_tag_set *set)
{
set->ops = &null_mq_ops;
set->nr_hw_queues = nullb ? nullb->dev->submit_queues :
g_submit_queues;
set->queue_depth = nullb ? nullb->dev->hw_queue_depth :
g_hw_queue_depth;
set->numa_node = nullb ? nullb->dev->home_node : g_home_node;
set->cmd_size = sizeof(struct nullb_cmd);
set->flags = BLK_MQ_F_SHOULD_MERGE;
if (g_no_sched)
set->flags |= BLK_MQ_F_NO_SCHED;
if (g_shared_tag_bitmap)
set->flags |= BLK_MQ_F_TAG_HCTX_SHARED;
set->driver_data = NULL;
if ((nullb && nullb->dev->blocking) || g_blocking)
set->flags |= BLK_MQ_F_BLOCKING;
return blk_mq_alloc_tag_set(set);
}
static int null_validate_conf(struct nullb_device *dev)
{
dev->blocksize = round_down(dev->blocksize, 512);
dev->blocksize = clamp_t(unsigned int, dev->blocksize, 512, 4096);
if (dev->queue_mode == NULL_Q_MQ && dev->use_per_node_hctx) {
if (dev->submit_queues != nr_online_nodes)
dev->submit_queues = nr_online_nodes;
} else if (dev->submit_queues > nr_cpu_ids)
dev->submit_queues = nr_cpu_ids;
else if (dev->submit_queues == 0)
dev->submit_queues = 1;
dev->queue_mode = min_t(unsigned int, dev->queue_mode, NULL_Q_MQ);
dev->irqmode = min_t(unsigned int, dev->irqmode, NULL_IRQ_TIMER);
/* Do memory allocation, so set blocking */
if (dev->memory_backed)
dev->blocking = true;
else /* cache is meaningless */
dev->cache_size = 0;
dev->cache_size = min_t(unsigned long, ULONG_MAX / 1024 / 1024,
dev->cache_size);
dev->mbps = min_t(unsigned int, 1024 * 40, dev->mbps);
/* can not stop a queue */
if (dev->queue_mode == NULL_Q_BIO)
dev->mbps = 0;
if (dev->zoned &&
(!dev->zone_size || !is_power_of_2(dev->zone_size))) {
pr_err("zone_size must be power-of-two\n");
return -EINVAL;
}
return 0;
}
#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
static bool __null_setup_fault(struct fault_attr *attr, char *str)
{
if (!str[0])
return true;
if (!setup_fault_attr(attr, str))
return false;
attr->verbose = 0;
return true;
}
#endif
static bool null_setup_fault(void)
{
#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
if (!__null_setup_fault(&null_timeout_attr, g_timeout_str))
return false;
if (!__null_setup_fault(&null_requeue_attr, g_requeue_str))
return false;
if (!__null_setup_fault(&null_init_hctx_attr, g_init_hctx_str))
return false;
#endif
return true;
}
static int null_add_dev(struct nullb_device *dev)
{
struct nullb *nullb;
int rv;
rv = null_validate_conf(dev);
if (rv)
return rv;
nullb = kzalloc_node(sizeof(*nullb), GFP_KERNEL, dev->home_node);
if (!nullb) {
rv = -ENOMEM;
goto out;
}
nullb->dev = dev;
dev->nullb = nullb;
spin_lock_init(&nullb->lock);
rv = setup_queues(nullb);
if (rv)
goto out_free_nullb;
if (dev->queue_mode == NULL_Q_MQ) {
if (shared_tags) {
nullb->tag_set = &tag_set;
rv = 0;
} else {
nullb->tag_set = &nullb->__tag_set;
rv = null_init_tag_set(nullb, nullb->tag_set);
}
if (rv)
goto out_cleanup_queues;
if (!null_setup_fault())
goto out_cleanup_queues;
nullb->tag_set->timeout = 5 * HZ;
nullb->q = blk_mq_init_queue_data(nullb->tag_set, nullb);
if (IS_ERR(nullb->q)) {
rv = -ENOMEM;
goto out_cleanup_tags;
}
} else if (dev->queue_mode == NULL_Q_BIO) {
nullb->q = blk_alloc_queue(dev->home_node);
if (!nullb->q) {
rv = -ENOMEM;
goto out_cleanup_queues;
}
rv = init_driver_queues(nullb);
if (rv)
goto out_cleanup_blk_queue;
}
if (dev->mbps) {
set_bit(NULLB_DEV_FL_THROTTLED, &dev->flags);
nullb_setup_bwtimer(nullb);
}
if (dev->cache_size > 0) {
set_bit(NULLB_DEV_FL_CACHE, &nullb->dev->flags);
blk_queue_write_cache(nullb->q, true, true);
}
if (dev->zoned) {
rv = null_init_zoned_dev(dev, nullb->q);
if (rv)
goto out_cleanup_blk_queue;
}
nullb->q->queuedata = nullb;
blk_queue_flag_set(QUEUE_FLAG_NONROT, nullb->q);
blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, nullb->q);
mutex_lock(&lock);
nullb->index = ida_simple_get(&nullb_indexes, 0, 0, GFP_KERNEL);
dev->index = nullb->index;
mutex_unlock(&lock);
blk_queue_logical_block_size(nullb->q, dev->blocksize);
blk_queue_physical_block_size(nullb->q, dev->blocksize);
null_config_discard(nullb);
sprintf(nullb->disk_name, "nullb%d", nullb->index);
rv = null_gendisk_register(nullb);
if (rv)
goto out_cleanup_zone;
mutex_lock(&lock);
list_add_tail(&nullb->list, &nullb_list);
mutex_unlock(&lock);
return 0;
out_cleanup_zone:
null_free_zoned_dev(dev);
out_cleanup_blk_queue:
blk_cleanup_queue(nullb->q);
out_cleanup_tags:
if (dev->queue_mode == NULL_Q_MQ && nullb->tag_set == &nullb->__tag_set)
blk_mq_free_tag_set(nullb->tag_set);
out_cleanup_queues:
cleanup_queues(nullb);
out_free_nullb:
kfree(nullb);
dev->nullb = NULL;
out:
return rv;
}
static int __init null_init(void)
{
int ret = 0;
unsigned int i;
struct nullb *nullb;
struct nullb_device *dev;
if (g_bs > PAGE_SIZE) {
pr_warn("invalid block size\n");
pr_warn("defaults block size to %lu\n", PAGE_SIZE);
g_bs = PAGE_SIZE;
}
if (g_home_node != NUMA_NO_NODE && g_home_node >= nr_online_nodes) {
pr_err("invalid home_node value\n");
g_home_node = NUMA_NO_NODE;
}
if (g_queue_mode == NULL_Q_RQ) {
pr_err("legacy IO path no longer available\n");
return -EINVAL;
}
if (g_queue_mode == NULL_Q_MQ && g_use_per_node_hctx) {
if (g_submit_queues != nr_online_nodes) {
pr_warn("submit_queues param is set to %u.\n",
nr_online_nodes);
g_submit_queues = nr_online_nodes;
}
} else if (g_submit_queues > nr_cpu_ids)
g_submit_queues = nr_cpu_ids;
else if (g_submit_queues <= 0)
g_submit_queues = 1;
if (g_queue_mode == NULL_Q_MQ && shared_tags) {
ret = null_init_tag_set(NULL, &tag_set);
if (ret)
return ret;
}
config_group_init(&nullb_subsys.su_group);
mutex_init(&nullb_subsys.su_mutex);
ret = configfs_register_subsystem(&nullb_subsys);
if (ret)
goto err_tagset;
mutex_init(&lock);
null_major = register_blkdev(0, "nullb");
if (null_major < 0) {
ret = null_major;
goto err_conf;
}
for (i = 0; i < nr_devices; i++) {
dev = null_alloc_dev();
if (!dev) {
ret = -ENOMEM;
goto err_dev;
}
ret = null_add_dev(dev);
if (ret) {
null_free_dev(dev);
goto err_dev;
}
}
pr_info("module loaded\n");
return 0;
err_dev:
while (!list_empty(&nullb_list)) {
nullb = list_entry(nullb_list.next, struct nullb, list);
dev = nullb->dev;
null_del_dev(nullb);
null_free_dev(dev);
}
unregister_blkdev(null_major, "nullb");
err_conf:
configfs_unregister_subsystem(&nullb_subsys);
err_tagset:
if (g_queue_mode == NULL_Q_MQ && shared_tags)
blk_mq_free_tag_set(&tag_set);
return ret;
}
static void __exit null_exit(void)
{
struct nullb *nullb;
configfs_unregister_subsystem(&nullb_subsys);
unregister_blkdev(null_major, "nullb");
mutex_lock(&lock);
while (!list_empty(&nullb_list)) {
struct nullb_device *dev;
nullb = list_entry(nullb_list.next, struct nullb, list);
dev = nullb->dev;
null_del_dev(nullb);
null_free_dev(dev);
}
mutex_unlock(&lock);
if (g_queue_mode == NULL_Q_MQ && shared_tags)
blk_mq_free_tag_set(&tag_set);
}
module_init(null_init);
module_exit(null_exit);
MODULE_AUTHOR("Jens Axboe <axboe@kernel.dk>");
MODULE_LICENSE("GPL");