#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/sched.h>
#include <linux/fs.h>
#include <linux/init.h>
#include "null_blk.h"
#undef pr_fmt
#define pr_fmt(fmt) "null_blk: " fmt
#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);
}
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)
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,
};
static bool g_virt_boundary;
module_param_named(virt_boundary, g_virt_boundary, bool, 0444);
MODULE_PARM_DESC(virt_boundary, "Require a virtual boundary for the device. Default: False");
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_poll_queues = 1;
module_param_named(poll_queues, g_poll_queues, int, 0444);
MODULE_PARM_DESC(poll_queues, "Number of IOPOLL 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
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
enum {
NULL_Q_BIO = 0,
NULL_Q_RQ = 1,
NULL_Q_MQ = 2,
};
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 int g_max_sectors;
module_param_named(max_sectors, g_max_sectors, int, 0444);
MODULE_PARM_DESC(max_sectors, "Maximum size of a command (in 512B sectors)");
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 g_shared_tags;
module_param_named(shared_tags, g_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_memory_backed;
module_param_named(memory_backed, g_memory_backed, bool, 0444);
MODULE_PARM_DESC(memory_backed, "Create a memory-backed block device. Default: false");
static bool g_discard;
module_param_named(discard, g_discard, bool, 0444);
MODULE_PARM_DESC(discard, "Support discard operations (requires memory-backed null_blk device). Default: false");
static unsigned long g_cache_size;
module_param_named(cache_size, g_cache_size, ulong, 0444);
MODULE_PARM_DESC(cache_size, "Cache size in MiB for memory-backed device. Default: 0 (none)");
static bool g_fua = true;
module_param_named(fua, g_fua, bool, 0444);
MODULE_PARM_DESC(fua, "Enable/disable FUA support when cache_size is used. Default: true");
static unsigned int g_mbps;
module_param_named(mbps, g_mbps, uint, 0444);
MODULE_PARM_DESC(mbps, "Limit maximum bandwidth (in MiB/s). Default: 0 (no limit)");
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 int g_zone_append_max_sectors = INT_MAX;
module_param_named(zone_append_max_sectors, g_zone_append_max_sectors, int, 0444);
MODULE_PARM_DESC(zone_append_max_sectors,
"Maximum size of a zone append command (in 512B sectors). Specify 0 for zone append emulation");
static bool g_zone_full;
module_param_named(zone_full, g_zone_full, bool, S_IRUGO);
MODULE_PARM_DESC(zone_full, "Initialize the sequential write required zones of a zoned device to be full. Default: false");
static bool g_rotational;
module_param_named(rotational, g_rotational, bool, S_IRUGO);
MODULE_PARM_DESC(rotational, "Set the rotational feature for the device. Default: false");
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 struct nullb *null_find_dev_by_name(const char *name);
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(to_config_group(item), struct nullb_device, group) : 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;
}
#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_update_nr_hw_queues(struct nullb_device *dev,
unsigned int submit_queues,
unsigned int poll_queues)
{
struct blk_mq_tag_set *set;
int ret, nr_hw_queues;
if (!dev->nullb)
return 0;
if (!submit_queues)
return -EINVAL;
if (submit_queues > nr_cpu_ids || poll_queues > g_poll_queues)
return -EINVAL;
dev->prev_submit_queues = dev->submit_queues;
dev->prev_poll_queues = dev->poll_queues;
dev->submit_queues = submit_queues;
dev->poll_queues = poll_queues;
set = dev->nullb->tag_set;
nr_hw_queues = submit_queues + poll_queues;
blk_mq_update_nr_hw_queues(set, nr_hw_queues);
ret = set->nr_hw_queues == nr_hw_queues ? 0 : -ENOMEM;
if (ret) {
dev->submit_queues = dev->prev_submit_queues;
dev->poll_queues = dev->prev_poll_queues;
}
return ret;
}
static int nullb_apply_submit_queues(struct nullb_device *dev,
unsigned int submit_queues)
{
int ret;
mutex_lock(&lock);
ret = nullb_update_nr_hw_queues(dev, submit_queues, dev->poll_queues);
mutex_unlock(&lock);
return ret;
}
static int nullb_apply_poll_queues(struct nullb_device *dev,
unsigned int poll_queues)
{
int ret;
mutex_lock(&lock);
ret = nullb_update_nr_hw_queues(dev, dev->submit_queues, poll_queues);
mutex_unlock(&lock);
return ret;
}
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(poll_queues, uint, nullb_apply_poll_queues);
NULLB_DEVICE_ATTR(home_node, uint, NULL);
NULLB_DEVICE_ATTR(queue_mode, uint, NULL);
NULLB_DEVICE_ATTR(blocksize, uint, NULL);
NULLB_DEVICE_ATTR(max_sectors, 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);
NULLB_DEVICE_ATTR(zone_append_max_sectors, uint, NULL);
NULLB_DEVICE_ATTR(zone_full, bool, NULL);
NULLB_DEVICE_ATTR(virt_boundary, bool, NULL);
NULLB_DEVICE_ATTR(no_sched, bool, NULL);
NULLB_DEVICE_ATTR(shared_tags, bool, NULL);
NULLB_DEVICE_ATTR(shared_tag_bitmap, bool, NULL);
NULLB_DEVICE_ATTR(fua, bool, NULL);
NULLB_DEVICE_ATTR(rotational, bool, NULL);
NULLB_DEVICE_ATTR(badblocks_once, bool, NULL);
NULLB_DEVICE_ATTR(badblocks_partial_io, bool, 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;
ret = count;
mutex_lock(&lock);
if (!dev->power && newp) {
if (test_and_set_bit(NULLB_DEV_FL_UP, &dev->flags))
goto out;
ret = null_add_dev(dev);
if (ret) {
clear_bit(NULLB_DEV_FL_UP, &dev->flags);
goto out;
}
set_bit(NULLB_DEV_FL_CONFIGURED, &dev->flags);
dev->power = newp;
ret = count;
} else if (dev->power && !newp) {
if (test_and_clear_bit(NULLB_DEV_FL_UP, &dev->flags)) {
dev->power = newp;
null_del_dev(dev->nullb);
}
clear_bit(NULLB_DEV_FL_CONFIGURED, &dev->flags);
}
out:
mutex_unlock(&lock);
return ret;
}
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;
cmpxchg(&t_dev->badblocks.shift, -1, 0);
if (buf[0] == '+') {
if (badblocks_set(&t_dev->badblocks, start,
end - start + 1, 1))
ret = count;
} else if (badblocks_clear(&t_dev->badblocks, start,
end - start + 1)) {
ret = count;
}
out:
kfree(orig);
return ret;
}
CONFIGFS_ATTR(nullb_device_, badblocks);
static ssize_t nullb_device_zone_readonly_store(struct config_item *item,
const char *page, size_t count)
{
struct nullb_device *dev = to_nullb_device(item);
return zone_cond_store(dev, page, count, BLK_ZONE_COND_READONLY);
}
CONFIGFS_ATTR_WO(nullb_device_, zone_readonly);
static ssize_t nullb_device_zone_offline_store(struct config_item *item,
const char *page, size_t count)
{
struct nullb_device *dev = to_nullb_device(item);
return zone_cond_store(dev, page, count, BLK_ZONE_COND_OFFLINE);
}
CONFIGFS_ATTR_WO(nullb_device_, zone_offline);
static struct configfs_attribute *nullb_device_attrs[] = {
&nullb_device_attr_badblocks,
&nullb_device_attr_badblocks_once,
&nullb_device_attr_badblocks_partial_io,
&nullb_device_attr_blocking,
&nullb_device_attr_blocksize,
&nullb_device_attr_cache_size,
&nullb_device_attr_completion_nsec,
&nullb_device_attr_discard,
&nullb_device_attr_fua,
&nullb_device_attr_home_node,
&nullb_device_attr_hw_queue_depth,
&nullb_device_attr_index,
&nullb_device_attr_irqmode,
&nullb_device_attr_max_sectors,
&nullb_device_attr_mbps,
&nullb_device_attr_memory_backed,
&nullb_device_attr_no_sched,
&nullb_device_attr_poll_queues,
&nullb_device_attr_power,
&nullb_device_attr_queue_mode,
&nullb_device_attr_rotational,
&nullb_device_attr_shared_tag_bitmap,
&nullb_device_attr_shared_tags,
&nullb_device_attr_size,
&nullb_device_attr_submit_queues,
&nullb_device_attr_use_per_node_hctx,
&nullb_device_attr_virt_boundary,
&nullb_device_attr_zone_append_max_sectors,
&nullb_device_attr_zone_capacity,
&nullb_device_attr_zone_full,
&nullb_device_attr_zone_max_active,
&nullb_device_attr_zone_max_open,
&nullb_device_attr_zone_nr_conv,
&nullb_device_attr_zone_offline,
&nullb_device_attr_zone_readonly,
&nullb_device_attr_zone_size,
&nullb_device_attr_zoned,
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 const 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,
};
#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
static void nullb_add_fault_config(struct nullb_device *dev)
{
fault_config_init(&dev->timeout_config, "timeout_inject");
fault_config_init(&dev->requeue_config, "requeue_inject");
fault_config_init(&dev->init_hctx_fault_config, "init_hctx_fault_inject");
configfs_add_default_group(&dev->timeout_config.group, &dev->group);
configfs_add_default_group(&dev->requeue_config.group, &dev->group);
configfs_add_default_group(&dev->init_hctx_fault_config.group, &dev->group);
}
static void nullb_del_fault_config(struct nullb_device *dev)
{
config_item_put(&dev->init_hctx_fault_config.group.cg_item);
config_item_put(&dev->requeue_config.group.cg_item);
config_item_put(&dev->timeout_config.group.cg_item);
}
#else
static void nullb_add_fault_config(struct nullb_device *dev)
{
}
static void nullb_del_fault_config(struct nullb_device *dev)
{
}
#endif
static struct
config_group *nullb_group_make_group(struct config_group *group, const char *name)
{
struct nullb_device *dev;
if (null_find_dev_by_name(name))
return ERR_PTR(-EEXIST);
dev = null_alloc_dev();
if (!dev)
return ERR_PTR(-ENOMEM);
config_group_init_type_name(&dev->group, name, &nullb_device_type);
nullb_add_fault_config(dev);
return &dev->group;
}
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);
}
nullb_del_fault_config(dev);
config_item_put(item);
}
static ssize_t memb_group_features_show(struct config_item *item, char *page)
{
struct configfs_attribute **entry;
char delimiter = ',';
size_t left = PAGE_SIZE;
size_t written = 0;
int ret;
for (entry = &nullb_device_attrs[0]; *entry && left > 0; entry++) {
if (!*(entry + 1))
delimiter = '\n';
ret = snprintf(page + written, left, "%s%c", (*entry)->ca_name,
delimiter);
if (ret >= left) {
WARN_ONCE(1, "Too many null_blk features to print\n");
memzero_explicit(page, PAGE_SIZE);
return -ENOBUFS;
}
left -= ret;
written += ret;
}
return written;
}
CONFIGFS_ATTR_RO(memb_group_, features);
static struct configfs_attribute *nullb_group_attrs[] = {
&memb_group_attr_features,
NULL,
};
static const struct configfs_group_operations nullb_group_ops = {
.make_group = nullb_group_make_group,
.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_obj(*dev);
if (!dev)
return NULL;
#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
dev->timeout_config.attr = null_timeout_attr;
dev->requeue_config.attr = null_requeue_attr;
dev->init_hctx_fault_config.attr = null_init_hctx_attr;
#endif
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->prev_submit_queues = g_submit_queues;
dev->poll_queues = g_poll_queues;
dev->prev_poll_queues = g_poll_queues;
dev->home_node = g_home_node;
dev->queue_mode = g_queue_mode;
dev->blocksize = g_bs;
dev->max_sectors = g_max_sectors;
dev->irqmode = g_irqmode;
dev->hw_queue_depth = g_hw_queue_depth;
dev->blocking = g_blocking;
dev->memory_backed = g_memory_backed;
dev->discard = g_discard;
dev->cache_size = g_cache_size;
dev->mbps = g_mbps;
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;
dev->zone_append_max_sectors = g_zone_append_max_sectors;
dev->zone_full = g_zone_full;
dev->virt_boundary = g_virt_boundary;
dev->no_sched = g_no_sched;
dev->shared_tags = g_shared_tags;
dev->shared_tag_bitmap = g_shared_tag_bitmap;
dev->fua = g_fua;
dev->rotational = g_rotational;
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 enum hrtimer_restart null_cmd_timer_expired(struct hrtimer *timer)
{
struct nullb_cmd *cmd = container_of(timer, struct nullb_cmd, timer);
blk_mq_end_request(blk_mq_rq_from_pdu(cmd), cmd->error);
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)
{
struct nullb_cmd *cmd = blk_mq_rq_to_pdu(rq);
blk_mq_end_request(rq, cmd->error);
}
static struct nullb_page *null_alloc_page(void)
{
struct nullb_page *t_page;
t_page = kmalloc_obj(struct nullb_page, GFP_NOIO);
if (!t_page)
return NULL;
t_page->page = alloc_pages(GFP_NOIO, 0);
if (!t_page->page) {
kfree(t_page);
return NULL;
}
memset(t_page->bitmap, 0, sizeof(t_page->bitmap));
return t_page;
}
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->private != 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->private;
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->private != 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();
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->private = 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->private;
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_local_page(c_page->page);
dst = kmap_local_page(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_local(dst);
kunmap_local(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);
for (i = 0; i < nr_pages; i++) {
nullb->cache_flush_pos = c_pages[i]->page->private;
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) {
spin_unlock_irq(&nullb->lock);
spin_lock_irq(&nullb->lock);
}
goto again;
}
return 0;
}
static blk_status_t copy_to_nullb(struct nullb *nullb, void *source,
loff_t pos, size_t n, bool is_fua)
{
size_t temp, count = 0;
struct nullb_page *t_page;
sector_t sector;
while (count < n) {
temp = min3(nullb->dev->blocksize, n - count,
PAGE_SIZE - offset_in_page(pos));
sector = pos >> SECTOR_SHIFT;
if (null_cache_active(nullb) && !is_fua)
null_make_cache_space(nullb, PAGE_SIZE);
t_page = null_insert_page(nullb, sector,
!null_cache_active(nullb) || is_fua);
if (!t_page)
return BLK_STS_NOSPC;
memcpy_to_page(t_page->page, offset_in_page(pos),
source + count, temp);
__set_bit(sector & SECTOR_MASK, t_page->bitmap);
if (is_fua)
null_free_sector(nullb, sector, true);
count += temp;
pos += temp;
}
return BLK_STS_OK;
}
static void copy_from_nullb(struct nullb *nullb, void *dest, loff_t pos,
size_t n)
{
size_t temp, count = 0;
struct nullb_page *t_page;
sector_t sector;
while (count < n) {
temp = min3(nullb->dev->blocksize, n - count,
PAGE_SIZE - offset_in_page(pos));
sector = pos >> SECTOR_SHIFT;
t_page = null_lookup_page(nullb, sector, false,
!null_cache_active(nullb));
if (t_page)
memcpy_from_page(dest + count, t_page->page,
offset_in_page(pos), temp);
else
memset(dest + count, 0, temp);
count += temp;
pos += temp;
}
}
blk_status_t null_handle_discard(struct nullb_device *dev,
sector_t sector, sector_t nr_sectors)
{
struct nullb *nullb = dev->nullb;
size_t n = nr_sectors << SECTOR_SHIFT;
size_t temp;
spin_lock_irq(&nullb->lock);
while (n > 0) {
temp = min_t(size_t, n, 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);
return BLK_STS_OK;
}
static blk_status_t 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 errno_to_blk_status(err);
}
static blk_status_t null_transfer(struct nullb *nullb, struct page *page,
unsigned int len, unsigned int off, bool is_write, loff_t pos,
bool is_fua)
{
struct nullb_device *dev = nullb->dev;
blk_status_t err = BLK_STS_OK;
unsigned int valid_len = len;
void *p;
p = kmap_local_page(page) + off;
if (!is_write) {
if (dev->zoned) {
valid_len = null_zone_valid_read_len(nullb,
pos >> SECTOR_SHIFT, len);
if (valid_len && valid_len != len)
valid_len -= pos & (SECTOR_SIZE - 1);
}
if (valid_len) {
copy_from_nullb(nullb, p, pos, valid_len);
off += valid_len;
len -= valid_len;
}
if (len)
memset(p + valid_len, 0xff, len);
flush_dcache_page(page);
} else {
flush_dcache_page(page);
err = copy_to_nullb(nullb, p, pos, len, is_fua);
}
kunmap_local(p);
return err;
}
static blk_status_t null_handle_data_transfer(struct nullb_cmd *cmd,
sector_t nr_sectors)
{
struct request *rq = blk_mq_rq_from_pdu(cmd);
struct nullb *nullb = cmd->nq->dev->nullb;
blk_status_t err = BLK_STS_OK;
unsigned int len;
loff_t pos = blk_rq_pos(rq) << SECTOR_SHIFT;
unsigned int max_bytes = nr_sectors << SECTOR_SHIFT;
unsigned int transferred_bytes = 0;
struct req_iterator iter;
struct bio_vec bvec;
spin_lock_irq(&nullb->lock);
rq_for_each_segment(bvec, rq, iter) {
len = bvec.bv_len;
if (transferred_bytes + len > max_bytes)
len = max_bytes - transferred_bytes;
err = null_transfer(nullb, bvec.bv_page, len, bvec.bv_offset,
op_is_write(req_op(rq)), pos,
rq->cmd_flags & REQ_FUA);
if (err)
break;
pos += len;
transferred_bytes += len;
if (transferred_bytes >= max_bytes)
break;
}
spin_unlock_irq(&nullb->lock);
return err;
}
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 = blk_mq_rq_from_pdu(cmd);
if (!hrtimer_active(&nullb->bw_timer))
hrtimer_restart(&nullb->bw_timer);
if (atomic_long_sub_return(blk_rq_bytes(rq), &nullb->cur_bytes) < 0) {
blk_mq_stop_hw_queues(nullb->q);
if (atomic_long_read(&nullb->cur_bytes) > 0)
blk_mq_start_stopped_hw_queues(nullb->q, true);
sts = BLK_STS_DEV_RESOURCE;
}
return sts;
}
blk_status_t null_handle_badblocks(struct nullb_cmd *cmd, sector_t sector,
unsigned int *nr_sectors)
{
struct badblocks *bb = &cmd->nq->dev->badblocks;
struct nullb_device *dev = cmd->nq->dev;
unsigned int block_sectors = dev->blocksize >> SECTOR_SHIFT;
sector_t first_bad, bad_sectors;
unsigned int partial_io_sectors = 0;
if (!badblocks_check(bb, sector, *nr_sectors, &first_bad, &bad_sectors))
return BLK_STS_OK;
if (cmd->nq->dev->badblocks_once)
badblocks_clear(bb, first_bad, bad_sectors);
if (cmd->nq->dev->badblocks_partial_io) {
if (!IS_ALIGNED(first_bad, block_sectors))
first_bad = ALIGN_DOWN(first_bad, block_sectors);
if (sector < first_bad)
partial_io_sectors = first_bad - sector;
}
*nr_sectors = partial_io_sectors;
return BLK_STS_IOERR;
}
blk_status_t null_handle_memory_backed(struct nullb_cmd *cmd, enum req_op op,
sector_t sector, sector_t nr_sectors)
{
struct nullb_device *dev = cmd->nq->dev;
if (op == REQ_OP_DISCARD)
return null_handle_discard(dev, sector, nr_sectors);
return null_handle_data_transfer(cmd, nr_sectors);
}
static void nullb_zero_read_cmd_buffer(struct nullb_cmd *cmd)
{
struct request *rq = blk_mq_rq_from_pdu(cmd);
struct nullb_device *dev = cmd->nq->dev;
struct bio *bio;
if (!dev->memory_backed && req_op(rq) == REQ_OP_READ) {
__rq_for_each_bio(bio, rq)
zero_fill_bio(bio);
}
}
static inline void nullb_complete_cmd(struct nullb_cmd *cmd)
{
struct request *rq = blk_mq_rq_from_pdu(cmd);
if (IS_ENABLED(CONFIG_KMSAN))
nullb_zero_read_cmd_buffer(cmd);
switch (cmd->nq->dev->irqmode) {
case NULL_IRQ_SOFTIRQ:
blk_mq_complete_request(rq);
break;
case NULL_IRQ_NONE:
blk_mq_end_request(rq, cmd->error);
break;
case NULL_IRQ_TIMER:
null_cmd_end_timer(cmd);
break;
}
}
blk_status_t null_process_cmd(struct nullb_cmd *cmd, enum req_op op,
sector_t sector, unsigned int nr_sectors)
{
struct nullb_device *dev = cmd->nq->dev;
blk_status_t badblocks_ret = BLK_STS_OK;
blk_status_t ret;
if (dev->badblocks.shift != -1)
badblocks_ret = null_handle_badblocks(cmd, sector, &nr_sectors);
if (dev->memory_backed && nr_sectors) {
ret = null_handle_memory_backed(cmd, op, sector, nr_sectors);
if (ret != BLK_STS_OK)
return ret;
}
return badblocks_ret;
}
static void null_handle_cmd(struct nullb_cmd *cmd, sector_t sector,
sector_t nr_sectors, enum req_op op)
{
struct nullb_device *dev = cmd->nq->dev;
struct nullb *nullb = dev->nullb;
blk_status_t sts;
if (op == REQ_OP_FLUSH) {
cmd->error = null_handle_flush(nullb);
goto out;
}
if (dev->zoned)
sts = null_process_zoned_cmd(cmd, op, sector, nr_sectors);
else
sts = null_process_cmd(cmd, op, sector, nr_sectors);
if (cmd->error == BLK_STS_OK)
cmd->error = sts;
out:
nullb_complete_cmd(cmd);
}
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));
blk_mq_start_stopped_hw_queues(nullb->q, true);
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_setup(&nullb->bw_timer, nullb_bwtimer_fn, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
atomic_long_set(&nullb->cur_bytes, mb_per_tick(nullb->dev->mbps));
hrtimer_start(&nullb->bw_timer, timer_interval, HRTIMER_MODE_REL);
}
#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
static bool should_timeout_request(struct request *rq)
{
struct nullb_cmd *cmd = blk_mq_rq_to_pdu(rq);
struct nullb_device *dev = cmd->nq->dev;
return should_fail(&dev->timeout_config.attr, 1);
}
static bool should_requeue_request(struct request *rq)
{
struct nullb_cmd *cmd = blk_mq_rq_to_pdu(rq);
struct nullb_device *dev = cmd->nq->dev;
return should_fail(&dev->requeue_config.attr, 1);
}
static bool should_init_hctx_fail(struct nullb_device *dev)
{
return should_fail(&dev->init_hctx_fault_config.attr, 1);
}
#else
static bool should_timeout_request(struct request *rq)
{
return false;
}
static bool should_requeue_request(struct request *rq)
{
return false;
}
static bool should_init_hctx_fail(struct nullb_device *dev)
{
return false;
}
#endif
static void null_map_queues(struct blk_mq_tag_set *set)
{
struct nullb *nullb = set->driver_data;
int i, qoff;
unsigned int submit_queues = g_submit_queues;
unsigned int poll_queues = g_poll_queues;
if (nullb) {
struct nullb_device *dev = nullb->dev;
if (set->nr_hw_queues ==
dev->submit_queues + dev->poll_queues) {
submit_queues = dev->submit_queues;
poll_queues = dev->poll_queues;
} else if (set->nr_hw_queues ==
dev->prev_submit_queues + dev->prev_poll_queues) {
submit_queues = dev->prev_submit_queues;
poll_queues = dev->prev_poll_queues;
} else {
pr_warn("tag set has unexpected nr_hw_queues: %d\n",
set->nr_hw_queues);
WARN_ON_ONCE(true);
submit_queues = 1;
poll_queues = 0;
}
}
for (i = 0, qoff = 0; i < set->nr_maps; i++) {
struct blk_mq_queue_map *map = &set->map[i];
switch (i) {
case HCTX_TYPE_DEFAULT:
map->nr_queues = submit_queues;
break;
case HCTX_TYPE_READ:
map->nr_queues = 0;
continue;
case HCTX_TYPE_POLL:
map->nr_queues = poll_queues;
break;
}
map->queue_offset = qoff;
qoff += map->nr_queues;
blk_mq_map_queues(map);
}
}
static int null_poll(struct blk_mq_hw_ctx *hctx, struct io_comp_batch *iob)
{
struct nullb_queue *nq = hctx->driver_data;
LIST_HEAD(list);
int nr = 0;
struct request *rq;
spin_lock(&nq->poll_lock);
list_splice_init(&nq->poll_list, &list);
list_for_each_entry(rq, &list, queuelist)
blk_mq_set_request_complete(rq);
spin_unlock(&nq->poll_lock);
while (!list_empty(&list)) {
struct nullb_cmd *cmd;
struct request *req;
req = list_first_entry(&list, struct request, queuelist);
list_del_init(&req->queuelist);
cmd = blk_mq_rq_to_pdu(req);
cmd->error = null_process_cmd(cmd, req_op(req), blk_rq_pos(req),
blk_rq_sectors(req));
if (!blk_mq_add_to_batch(req, iob, cmd->error != BLK_STS_OK,
blk_mq_end_request_batch))
blk_mq_end_request(req, cmd->error);
nr++;
}
return nr;
}
static enum blk_eh_timer_return null_timeout_rq(struct request *rq)
{
struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
struct nullb_cmd *cmd = blk_mq_rq_to_pdu(rq);
if (hctx->type == HCTX_TYPE_POLL) {
struct nullb_queue *nq = hctx->driver_data;
spin_lock(&nq->poll_lock);
if (blk_mq_request_completed(rq)) {
spin_unlock(&nq->poll_lock);
return BLK_EH_DONE;
}
list_del_init(&rq->queuelist);
spin_unlock(&nq->poll_lock);
}
pr_info("rq %p timed out\n", rq);
cmd->error = BLK_STS_TIMEOUT;
if (cmd->fake_timeout || hctx->type == HCTX_TYPE_POLL)
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 request *rq = bd->rq;
struct nullb_cmd *cmd = blk_mq_rq_to_pdu(rq);
struct nullb_queue *nq = hctx->driver_data;
sector_t nr_sectors = blk_rq_sectors(rq);
sector_t sector = blk_rq_pos(rq);
const bool is_poll = hctx->type == HCTX_TYPE_POLL;
might_sleep_if(hctx->flags & BLK_MQ_F_BLOCKING);
if (!is_poll && nq->dev->irqmode == NULL_IRQ_TIMER) {
hrtimer_setup(&cmd->timer, null_cmd_timer_expired, CLOCK_MONOTONIC,
HRTIMER_MODE_REL);
}
cmd->error = BLK_STS_OK;
cmd->nq = nq;
cmd->fake_timeout = should_timeout_request(rq) ||
blk_should_fake_timeout(rq->q);
if (should_requeue_request(rq)) {
nq->requeue_selection++;
if (nq->requeue_selection & 1)
return BLK_STS_RESOURCE;
blk_mq_requeue_request(rq, true);
return BLK_STS_OK;
}
if (test_bit(NULLB_DEV_FL_THROTTLED, &nq->dev->flags)) {
blk_status_t sts = null_handle_throttled(cmd);
if (sts != BLK_STS_OK)
return sts;
}
blk_mq_start_request(rq);
if (is_poll) {
spin_lock(&nq->poll_lock);
list_add_tail(&rq->queuelist, &nq->poll_list);
spin_unlock(&nq->poll_lock);
return BLK_STS_OK;
}
if (cmd->fake_timeout)
return BLK_STS_OK;
null_handle_cmd(cmd, sector, nr_sectors, req_op(rq));
return BLK_STS_OK;
}
static void null_queue_rqs(struct rq_list *rqlist)
{
struct rq_list requeue_list = {};
struct blk_mq_queue_data bd = { };
blk_status_t ret;
do {
struct request *rq = rq_list_pop(rqlist);
bd.rq = rq;
ret = null_queue_rq(rq->mq_hctx, &bd);
if (ret != BLK_STS_OK)
rq_list_add_tail(&requeue_list, rq);
} while (!rq_list_empty(rqlist));
*rqlist = requeue_list;
}
static void null_init_queue(struct nullb *nullb, struct nullb_queue *nq)
{
nq->dev = nullb->dev;
INIT_LIST_HEAD(&nq->poll_list);
spin_lock_init(&nq->poll_lock);
}
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;
if (should_init_hctx_fail(nullb->dev))
return -EFAULT;
nq = &nullb->queues[hctx_idx];
hctx->driver_data = nq;
null_init_queue(nullb, nq);
return 0;
}
static const struct blk_mq_ops null_mq_ops = {
.queue_rq = null_queue_rq,
.queue_rqs = null_queue_rqs,
.complete = null_complete_rq,
.timeout = null_timeout_rq,
.poll = null_poll,
.map_queues = null_map_queues,
.init_hctx = null_init_hctx,
};
static void null_del_dev(struct nullb *nullb)
{
struct nullb_device *dev;
if (!nullb)
return;
dev = nullb->dev;
ida_free(&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);
blk_mq_start_stopped_hw_queues(nullb->q, true);
}
put_disk(nullb->disk);
if (nullb->tag_set == &nullb->__tag_set)
blk_mq_free_tag_set(nullb->tag_set);
kfree(nullb->queues);
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, struct queue_limits *lim)
{
if (nullb->dev->discard == false)
return;
if (!nullb->dev->memory_backed) {
nullb->dev->discard = false;
pr_info("discard option is ignored without memory backing\n");
return;
}
if (nullb->dev->zoned) {
nullb->dev->discard = false;
pr_info("discard option is ignored in zoned mode\n");
return;
}
lim->max_hw_discard_sectors = UINT_MAX >> 9;
}
static const struct block_device_operations null_ops = {
.owner = THIS_MODULE,
.report_zones = null_report_zones,
};
static int setup_queues(struct nullb *nullb)
{
int nqueues = nr_cpu_ids;
if (g_poll_queues)
nqueues += g_poll_queues;
nullb->queues = kzalloc_objs(struct nullb_queue, nqueues);
if (!nullb->queues)
return -ENOMEM;
return 0;
}
static int null_init_tag_set(struct blk_mq_tag_set *set, int poll_queues)
{
set->ops = &null_mq_ops;
set->cmd_size = sizeof(struct nullb_cmd);
set->timeout = 5 * HZ;
set->nr_maps = 1;
if (poll_queues) {
set->nr_hw_queues += poll_queues;
set->nr_maps += 2;
}
return blk_mq_alloc_tag_set(set);
}
static int null_init_global_tag_set(void)
{
int error;
if (tag_set.ops)
return 0;
tag_set.nr_hw_queues = g_submit_queues;
tag_set.queue_depth = g_hw_queue_depth;
tag_set.numa_node = g_home_node;
if (g_no_sched)
tag_set.flags |= BLK_MQ_F_NO_SCHED_BY_DEFAULT;
if (g_shared_tag_bitmap)
tag_set.flags |= BLK_MQ_F_TAG_HCTX_SHARED;
if (g_blocking)
tag_set.flags |= BLK_MQ_F_BLOCKING;
error = null_init_tag_set(&tag_set, g_poll_queues);
if (error)
tag_set.ops = NULL;
return error;
}
static int null_setup_tagset(struct nullb *nullb)
{
if (nullb->dev->shared_tags) {
nullb->tag_set = &tag_set;
return null_init_global_tag_set();
}
nullb->tag_set = &nullb->__tag_set;
nullb->tag_set->driver_data = nullb;
nullb->tag_set->nr_hw_queues = nullb->dev->submit_queues;
nullb->tag_set->queue_depth = nullb->dev->hw_queue_depth;
nullb->tag_set->numa_node = nullb->dev->home_node;
if (nullb->dev->no_sched)
nullb->tag_set->flags |= BLK_MQ_F_NO_SCHED_BY_DEFAULT;
if (nullb->dev->shared_tag_bitmap)
nullb->tag_set->flags |= BLK_MQ_F_TAG_HCTX_SHARED;
if (nullb->dev->blocking)
nullb->tag_set->flags |= BLK_MQ_F_BLOCKING;
return null_init_tag_set(nullb->tag_set, nullb->dev->poll_queues);
}
static int null_validate_conf(struct nullb_device *dev)
{
if (dev->queue_mode == NULL_Q_RQ) {
pr_err("legacy IO path is no longer available\n");
return -EINVAL;
}
if (dev->queue_mode == NULL_Q_BIO) {
pr_err("BIO-based IO path is no longer available, using blk-mq instead.\n");
dev->queue_mode = NULL_Q_MQ;
}
if (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->prev_submit_queues = dev->submit_queues;
if (dev->poll_queues > g_poll_queues)
dev->poll_queues = g_poll_queues;
dev->prev_poll_queues = dev->poll_queues;
dev->irqmode = min_t(unsigned int, dev->irqmode, NULL_IRQ_TIMER);
if (dev->memory_backed)
dev->blocking = true;
else
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);
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 queue_limits lim = {
.logical_block_size = dev->blocksize,
.physical_block_size = dev->blocksize,
.max_hw_sectors = dev->max_sectors,
.dma_alignment = 1,
};
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;
rv = null_setup_tagset(nullb);
if (rv)
goto out_cleanup_queues;
if (dev->virt_boundary)
lim.virt_boundary_mask = PAGE_SIZE - 1;
null_config_discard(nullb, &lim);
if (dev->zoned) {
rv = null_init_zoned_dev(dev, &lim);
if (rv)
goto out_cleanup_tags;
}
if (dev->cache_size > 0) {
set_bit(NULLB_DEV_FL_CACHE, &nullb->dev->flags);
lim.features |= BLK_FEAT_WRITE_CACHE;
if (dev->fua)
lim.features |= BLK_FEAT_FUA;
}
if (dev->rotational)
lim.features |= BLK_FEAT_ROTATIONAL;
nullb->disk = blk_mq_alloc_disk(nullb->tag_set, &lim, nullb);
if (IS_ERR(nullb->disk)) {
rv = PTR_ERR(nullb->disk);
goto out_cleanup_zone;
}
nullb->q = nullb->disk->queue;
if (dev->mbps) {
set_bit(NULLB_DEV_FL_THROTTLED, &dev->flags);
nullb_setup_bwtimer(nullb);
}
nullb->q->queuedata = nullb;
rv = ida_alloc(&nullb_indexes, GFP_KERNEL);
if (rv < 0)
goto out_cleanup_disk;
nullb->index = rv;
dev->index = rv;
if (config_item_name(&dev->group.cg_item)) {
snprintf(nullb->disk_name, sizeof(nullb->disk_name),
"%s", config_item_name(&dev->group.cg_item));
} else {
sprintf(nullb->disk_name, "nullb%d", nullb->index);
}
set_capacity(nullb->disk,
((sector_t)nullb->dev->size * SZ_1M) >> SECTOR_SHIFT);
nullb->disk->major = null_major;
nullb->disk->first_minor = nullb->index;
nullb->disk->minors = 1;
nullb->disk->fops = &null_ops;
nullb->disk->private_data = nullb;
strscpy(nullb->disk->disk_name, nullb->disk_name);
if (nullb->dev->zoned) {
rv = null_register_zoned_dev(nullb);
if (rv)
goto out_ida_free;
}
rv = add_disk(nullb->disk);
if (rv)
goto out_ida_free;
list_add_tail(&nullb->list, &nullb_list);
pr_info("disk %s created\n", nullb->disk_name);
return 0;
out_ida_free:
ida_free(&nullb_indexes, nullb->index);
out_cleanup_disk:
put_disk(nullb->disk);
out_cleanup_zone:
null_free_zoned_dev(dev);
out_cleanup_tags:
if (nullb->tag_set == &nullb->__tag_set)
blk_mq_free_tag_set(nullb->tag_set);
out_cleanup_queues:
kfree(nullb->queues);
out_free_nullb:
kfree(nullb);
dev->nullb = NULL;
out:
return rv;
}
static struct nullb *null_find_dev_by_name(const char *name)
{
struct nullb *nullb = NULL, *nb;
mutex_lock(&lock);
list_for_each_entry(nb, &nullb_list, list) {
if (strcmp(nb->disk_name, name) == 0) {
nullb = nb;
break;
}
}
mutex_unlock(&lock);
return nullb;
}
static int null_create_dev(void)
{
struct nullb_device *dev;
int ret;
dev = null_alloc_dev();
if (!dev)
return -ENOMEM;
mutex_lock(&lock);
ret = null_add_dev(dev);
mutex_unlock(&lock);
if (ret) {
null_free_dev(dev);
return ret;
}
return 0;
}
static void null_destroy_dev(struct nullb *nullb)
{
struct nullb_device *dev = nullb->dev;
null_del_dev(nullb);
null_free_device_storage(dev, false);
null_free_dev(dev);
}
static int __init null_init(void)
{
int ret = 0;
unsigned int i;
struct nullb *nullb;
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 (!null_setup_fault())
return -EINVAL;
if (g_queue_mode == NULL_Q_RQ) {
pr_err("legacy IO path is no longer available\n");
return -EINVAL;
}
if (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;
}
config_group_init(&nullb_subsys.su_group);
mutex_init(&nullb_subsys.su_mutex);
ret = configfs_register_subsystem(&nullb_subsys);
if (ret)
return ret;
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++) {
ret = null_create_dev();
if (ret)
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);
null_destroy_dev(nullb);
}
unregister_blkdev(null_major, "nullb");
err_conf:
configfs_unregister_subsystem(&nullb_subsys);
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)) {
nullb = list_entry(nullb_list.next, struct nullb, list);
null_destroy_dev(nullb);
}
mutex_unlock(&lock);
if (tag_set.ops)
blk_mq_free_tag_set(&tag_set);
mutex_destroy(&lock);
}
module_init(null_init);
module_exit(null_exit);
MODULE_AUTHOR("Jens Axboe <axboe@kernel.dk>");
MODULE_DESCRIPTION("multi queue aware block test driver");
MODULE_LICENSE("GPL");
