linux/drivers/block/null_blk.c

1953 lines
46 KiB
C

/*
* 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/blkdev.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/blk-mq.h>
#include <linux/hrtimer.h>
#include <linux/configfs.h>
#include <linux/badblocks.h>
#include <linux/fault-inject.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);
#endif
static inline u64 mb_per_tick(int mbps)
{
return (1 << 20) / TICKS_PER_SEC * ((u64) mbps);
}
struct nullb_cmd {
struct list_head list;
struct llist_node ll_list;
struct __call_single_data csd;
struct request *rq;
struct bio *bio;
unsigned int tag;
blk_status_t error;
struct nullb_queue *nq;
struct hrtimer timer;
};
struct nullb_queue {
unsigned long *tag_map;
wait_queue_head_t wait;
unsigned int queue_depth;
struct nullb_device *dev;
unsigned int requeue_selection;
struct nullb_cmd *cmds;
};
/*
* 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)
struct nullb_device {
struct nullb *nullb;
struct config_item item;
struct radix_tree_root data; /* data stored in the disk */
struct radix_tree_root cache; /* disk cache data */
unsigned long flags; /* device flags */
unsigned int curr_cache;
struct badblocks badblocks;
unsigned long size; /* device size in MB */
unsigned long completion_nsec; /* time in ns to complete a request */
unsigned long cache_size; /* disk cache size in MB */
unsigned int submit_queues; /* number of submission queues */
unsigned int home_node; /* home node for the device */
unsigned int queue_mode; /* block interface */
unsigned int blocksize; /* block size */
unsigned int irqmode; /* IRQ completion handler */
unsigned int hw_queue_depth; /* queue depth */
unsigned int index; /* index of the disk, only valid with a disk */
unsigned int mbps; /* Bandwidth throttle cap (in MB/s) */
bool blocking; /* blocking blk-mq device */
bool use_per_node_hctx; /* use per-node allocation for hardware context */
bool power; /* power on/off the device */
bool memory_backed; /* if data is stored in memory */
bool discard; /* if support discard */
};
struct nullb {
struct nullb_device *dev;
struct list_head list;
unsigned int index;
struct request_queue *q;
struct gendisk *disk;
struct blk_mq_tag_set *tag_set;
struct blk_mq_tag_set __tag_set;
unsigned int queue_depth;
atomic_long_t cur_bytes;
struct hrtimer bw_timer;
unsigned long cache_flush_pos;
spinlock_t lock;
struct nullb_queue *queues;
unsigned int nr_queues;
char disk_name[DISK_NAME_LEN];
};
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, S_IRUGO);
MODULE_PARM_DESC(no_sched, "No io scheduler");
static int g_submit_queues = 1;
module_param_named(submit_queues, g_submit_queues, int, S_IRUGO);
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, S_IRUGO);
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), S_IRUGO);
static char g_requeue_str[80];
module_param_string(requeue, g_requeue_str, sizeof(g_requeue_str), S_IRUGO);
#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, S_IRUGO);
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, S_IRUGO);
MODULE_PARM_DESC(gb, "Size in GB");
static int g_bs = 512;
module_param_named(bs, g_bs, int, S_IRUGO);
MODULE_PARM_DESC(bs, "Block size (in bytes)");
static int nr_devices = 1;
module_param(nr_devices, int, S_IRUGO);
MODULE_PARM_DESC(nr_devices, "Number of devices to register");
static bool g_blocking;
module_param_named(blocking, g_blocking, bool, S_IRUGO);
MODULE_PARM_DESC(blocking, "Register as a blocking blk-mq driver device");
static bool shared_tags;
module_param(shared_tags, bool, S_IRUGO);
MODULE_PARM_DESC(shared_tags, "Share tag set between devices 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, S_IRUGO);
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, S_IRUGO);
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, S_IRUGO);
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, S_IRUGO);
MODULE_PARM_DESC(use_per_node_hctx, "Use per-node allocation for hardware context queues. 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 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)
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)
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)
return result;
*val = tmp;
return count;
}
/* The following macro should only be used with TYPE = {uint, ulong, bool}. */
#define NULLB_DEVICE_ATTR(NAME, TYPE) \
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) \
{ \
if (test_bit(NULLB_DEV_FL_CONFIGURED, &to_nullb_device(item)->flags)) \
return -EBUSY; \
return nullb_device_##TYPE##_attr_store( \
&to_nullb_device(item)->NAME, page, count); \
} \
CONFIGFS_ATTR(nullb_device_, NAME);
NULLB_DEVICE_ATTR(size, ulong);
NULLB_DEVICE_ATTR(completion_nsec, ulong);
NULLB_DEVICE_ATTR(submit_queues, uint);
NULLB_DEVICE_ATTR(home_node, uint);
NULLB_DEVICE_ATTR(queue_mode, uint);
NULLB_DEVICE_ATTR(blocksize, uint);
NULLB_DEVICE_ATTR(irqmode, uint);
NULLB_DEVICE_ATTR(hw_queue_depth, uint);
NULLB_DEVICE_ATTR(index, uint);
NULLB_DEVICE_ATTR(blocking, bool);
NULLB_DEVICE_ATTR(use_per_node_hctx, bool);
NULLB_DEVICE_ATTR(memory_backed, bool);
NULLB_DEVICE_ATTR(discard, bool);
NULLB_DEVICE_ATTR(mbps, uint);
NULLB_DEVICE_ATTR(cache_size, ulong);
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) {
mutex_lock(&lock);
dev->power = newp;
null_del_dev(dev->nullb);
mutex_unlock(&lock);
clear_bit(NULLB_DEV_FL_UP, &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,
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\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;
return dev;
}
static void null_free_dev(struct nullb_device *dev)
{
if (!dev)
return;
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->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)
{
struct request_queue *q = NULL;
int queue_mode = cmd->nq->dev->queue_mode;
if (cmd->rq)
q = cmd->rq->q;
switch (queue_mode) {
case NULL_Q_MQ:
blk_mq_end_request(cmd->rq, cmd->error);
return;
case NULL_Q_RQ:
INIT_LIST_HEAD(&cmd->rq->queuelist);
blk_end_request_all(cmd->rq, cmd->error);
break;
case NULL_Q_BIO:
cmd->bio->bi_status = cmd->error;
bio_endio(cmd->bio);
break;
}
free_cmd(cmd);
/* Restart queue if needed, as we are freeing a tag */
if (queue_mode == NULL_Q_RQ && blk_queue_stopped(q)) {
unsigned long flags;
spin_lock_irqsave(q->queue_lock, flags);
blk_start_queue_async(q);
spin_unlock_irqrestore(q->queue_lock, flags);
}
}
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_softirq_done_fn(struct request *rq)
{
struct nullb *nullb = rq->q->queuedata;
if (nullb->dev->queue_mode == NULL_Q_MQ)
end_cmd(blk_mq_rq_to_pdu(rq));
else
end_cmd(rq->special);
}
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)
{
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 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)
{
int err = 0;
if (!is_write) {
err = copy_from_nullb(nullb, page, off, sector, len);
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,
req_op(rq) & 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_op(bio) & 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);
else {
spin_lock_irq(q->queue_lock);
blk_stop_queue(q);
spin_unlock_irq(q->queue_lock);
}
}
static void null_restart_queue_async(struct nullb *nullb)
{
struct request_queue *q = nullb->q;
unsigned long flags;
if (nullb->dev->queue_mode == NULL_Q_MQ)
blk_mq_start_stopped_hw_queues(q, true);
else {
spin_lock_irqsave(q->queue_lock, flags);
blk_start_queue_async(q);
spin_unlock_irqrestore(q->queue_lock, flags);
}
}
static blk_status_t null_handle_cmd(struct nullb_cmd *cmd)
{
struct nullb_device *dev = cmd->nq->dev;
struct nullb *nullb = dev->nullb;
int err = 0;
if (test_bit(NULLB_DEV_FL_THROTTLED, &dev->flags)) {
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);
if (dev->queue_mode == NULL_Q_RQ) {
struct request_queue *q = nullb->q;
spin_lock_irq(q->queue_lock);
rq->rq_flags |= RQF_DONTPREP;
blk_requeue_request(q, rq);
spin_unlock_irq(q->queue_lock);
return BLK_STS_OK;
} else
/* requeue request */
return BLK_STS_DEV_RESOURCE;
}
}
if (nullb->dev->badblocks.shift != -1) {
int bad_sectors;
sector_t sector, size, first_bad;
bool is_flush = true;
if (dev->queue_mode == NULL_Q_BIO &&
bio_op(cmd->bio) != REQ_OP_FLUSH) {
is_flush = false;
sector = cmd->bio->bi_iter.bi_sector;
size = bio_sectors(cmd->bio);
}
if (dev->queue_mode != NULL_Q_BIO &&
req_op(cmd->rq) != REQ_OP_FLUSH) {
is_flush = false;
sector = blk_rq_pos(cmd->rq);
size = blk_rq_sectors(cmd->rq);
}
if (!is_flush && badblocks_check(&nullb->dev->badblocks, sector,
size, &first_bad, &bad_sectors)) {
cmd->error = BLK_STS_IOERR;
goto out;
}
}
if (dev->memory_backed) {
if (dev->queue_mode == NULL_Q_BIO) {
if (bio_op(cmd->bio) == REQ_OP_FLUSH)
err = null_handle_flush(nullb);
else
err = null_handle_bio(cmd);
} else {
if (req_op(cmd->rq) == REQ_OP_FLUSH)
err = null_handle_flush(nullb);
else
err = null_handle_rq(cmd);
}
}
cmd->error = errno_to_blk_status(err);
out:
/* Complete IO by inline, softirq or timer */
switch (dev->irqmode) {
case NULL_IRQ_SOFTIRQ:
switch (dev->queue_mode) {
case NULL_Q_MQ:
blk_mq_complete_request(cmd->rq);
break;
case NULL_Q_RQ:
blk_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;
}
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_queue_bio(struct request_queue *q, struct bio *bio)
{
struct nullb *nullb = q->queuedata;
struct nullb_queue *nq = nullb_to_queue(nullb);
struct nullb_cmd *cmd;
cmd = alloc_cmd(nq, 1);
cmd->bio = bio;
null_handle_cmd(cmd);
return BLK_QC_T_NONE;
}
static enum blk_eh_timer_return null_rq_timed_out_fn(struct request *rq)
{
pr_info("null: rq %p timed out\n", rq);
return BLK_EH_HANDLED;
}
static int null_rq_prep_fn(struct request_queue *q, struct request *req)
{
struct nullb *nullb = q->queuedata;
struct nullb_queue *nq = nullb_to_queue(nullb);
struct nullb_cmd *cmd;
cmd = alloc_cmd(nq, 0);
if (cmd) {
cmd->rq = req;
req->special = cmd;
return BLKPREP_OK;
}
blk_stop_queue(q);
return BLKPREP_DEFER;
}
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 void null_request_fn(struct request_queue *q)
{
struct request *rq;
while ((rq = blk_fetch_request(q)) != NULL) {
struct nullb_cmd *cmd = rq->special;
/* just ignore the request */
if (should_timeout_request(rq))
continue;
if (should_requeue_request(rq)) {
blk_requeue_request(q, rq);
continue;
}
spin_unlock_irq(q->queue_lock);
null_handle_cmd(cmd);
spin_lock_irq(q->queue_lock);
}
}
static enum blk_eh_timer_return null_timeout_rq(struct request *rq, bool res)
{
pr_info("null: rq %p timed out\n", rq);
return BLK_EH_HANDLED;
}
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;
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->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);
}
static const struct blk_mq_ops null_mq_ops = {
.queue_rq = null_queue_rq,
.complete = null_softirq_done_fn,
.timeout = null_timeout_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_del_dev(struct nullb *nullb)
{
struct nullb_device *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;
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 int null_open(struct block_device *bdev, fmode_t mode)
{
return 0;
}
static void null_release(struct gendisk *disk, fmode_t mode)
{
}
static const struct block_device_operations null_fops = {
.owner = THIS_MODULE,
.open = null_open,
.release = null_release,
};
static void null_init_queue(struct nullb *nullb, struct nullb_queue *nq)
{
BUG_ON(!nullb);
BUG_ON(!nq);
init_waitqueue_head(&nq->wait);
nq->queue_depth = nullb->queue_depth;
nq->dev = nullb->dev;
}
static void null_init_queues(struct nullb *nullb)
{
struct request_queue *q = nullb->q;
struct blk_mq_hw_ctx *hctx;
struct nullb_queue *nq;
int i;
queue_for_each_hw_ctx(q, hctx, i) {
if (!hctx->nr_ctx || !hctx->tags)
continue;
nq = &nullb->queues[i];
hctx->driver_data = nq;
null_init_queue(nullb, nq);
nullb->nr_queues++;
}
}
static int setup_commands(struct nullb_queue *nq)
{
struct nullb_cmd *cmd;
int i, tag_size;
nq->cmds = kzalloc(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 = kzalloc(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];
INIT_LIST_HEAD(&cmd->list);
cmd->ll_list.next = NULL;
cmd->tag = -1U;
}
return 0;
}
static int setup_queues(struct nullb *nullb)
{
nullb->queues = kzalloc(nullb->dev->submit_queues *
sizeof(struct nullb_queue), GFP_KERNEL);
if (!nullb->queues)
return -ENOMEM;
nullb->nr_queues = 0;
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)
{
struct gendisk *disk;
sector_t size;
disk = nullb->disk = alloc_disk_node(1, nullb->dev->home_node);
if (!disk)
return -ENOMEM;
size = (sector_t)nullb->dev->size * 1024 * 1024ULL;
set_capacity(disk, size >> 9);
disk->flags |= GENHD_FL_EXT_DEVT | GENHD_FL_SUPPRESS_PARTITION_INFO;
disk->major = null_major;
disk->first_minor = nullb->index;
disk->fops = &null_fops;
disk->private_data = nullb;
disk->queue = nullb->q;
strncpy(disk->disk_name, nullb->disk_name, DISK_NAME_LEN);
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;
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 void 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;
}
#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;
#endif
return true;
}
static int null_add_dev(struct nullb_device *dev)
{
struct nullb *nullb;
int rv;
null_validate_conf(dev);
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(nullb->tag_set);
if (IS_ERR(nullb->q)) {
rv = -ENOMEM;
goto out_cleanup_tags;
}
null_init_queues(nullb);
} else if (dev->queue_mode == NULL_Q_BIO) {
nullb->q = blk_alloc_queue_node(GFP_KERNEL, dev->home_node,
NULL);
if (!nullb->q) {
rv = -ENOMEM;
goto out_cleanup_queues;
}
blk_queue_make_request(nullb->q, null_queue_bio);
rv = init_driver_queues(nullb);
if (rv)
goto out_cleanup_blk_queue;
} else {
nullb->q = blk_init_queue_node(null_request_fn, &nullb->lock,
dev->home_node);
if (!nullb->q) {
rv = -ENOMEM;
goto out_cleanup_queues;
}
if (!null_setup_fault())
goto out_cleanup_blk_queue;
blk_queue_prep_rq(nullb->q, null_rq_prep_fn);
blk_queue_softirq_done(nullb->q, null_softirq_done_fn);
blk_queue_rq_timed_out(nullb->q, null_rq_timed_out_fn);
nullb->q->rq_timeout = 5 * HZ;
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);
blk_queue_flush_queueable(nullb->q, true);
}
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_blk_queue;
mutex_lock(&lock);
list_add_tail(&nullb->list, &nullb_list);
mutex_unlock(&lock);
return 0;
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);
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("null_blk: invalid block size\n");
pr_warn("null_blk: defaults block size to %lu\n", PAGE_SIZE);
g_bs = PAGE_SIZE;
}
if (g_queue_mode == NULL_Q_MQ && g_use_per_node_hctx) {
if (g_submit_queues != nr_online_nodes) {
pr_warn("null_blk: 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("null: 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");