Shaohua Li 306eb6b4ad nullb: support discard
discard makes sense for memory backed disk. And also it's useful to test
if upper layer supports dicard correctly.

User configures 'discard' attribute to enable/disable dicard support.

Based on original patch from Kyungchan Koh

Signed-off-by: Kyungchan Koh <kkc6196@fb.com>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-08-23 08:54:08 -06:00

1649 lines
38 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/lightnvm.h>
#include <linux/configfs.h>
#define SECTOR_SHIFT 9
#define PAGE_SECTORS_SHIFT (PAGE_SHIFT - SECTOR_SHIFT)
#define PAGE_SECTORS (1 << PAGE_SECTORS_SHIFT)
#define SECTOR_SIZE (1 << SECTOR_SHIFT)
#define SECTOR_MASK (PAGE_SECTORS - 1)
#define FREE_BATCH 16
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;
struct nullb_queue *nq;
struct hrtimer timer;
blk_status_t error;
};
struct nullb_queue {
unsigned long *tag_map;
wait_queue_head_t wait;
unsigned int queue_depth;
struct nullb_device *dev;
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.
*/
enum nullb_device_flags {
NULLB_DEV_FL_CONFIGURED = 0,
NULLB_DEV_FL_UP = 1,
};
/*
* 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
*/
struct nullb_page {
struct page *page;
unsigned long bitmap;
};
struct nullb_device {
struct nullb *nullb;
struct config_item item;
struct radix_tree_root data; /* data stored in the disk */
unsigned long flags; /* device flags */
unsigned long size; /* device size in MB */
unsigned long completion_nsec; /* time in ns to complete a request */
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 */
bool use_lightnvm; /* register as a LightNVM device */
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 nvm_dev *ndev;
struct blk_mq_tag_set *tag_set;
struct blk_mq_tag_set __tag_set;
struct hrtimer timer;
unsigned int queue_depth;
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 kmem_cache *ppa_cache;
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_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");
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_use_lightnvm;
module_param_named(use_lightnvm, g_use_lightnvm, bool, S_IRUGO);
MODULE_PARM_DESC(use_lightnvm, "Register as a LightNVM device");
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);
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(use_lightnvm, bool);
NULLB_DEVICE_ATTR(blocking, bool);
NULLB_DEVICE_ATTR(use_per_node_hctx, bool);
NULLB_DEVICE_ATTR(memory_backed, bool);
NULLB_DEVICE_ATTR(discard, bool);
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 (to_nullb_device(item)->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 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_use_lightnvm,
&nullb_device_attr_blocking,
&nullb_device_attr_use_per_node_hctx,
&nullb_device_attr_power,
&nullb_device_attr_memory_backed,
&nullb_device_attr_discard,
NULL,
};
static void nullb_device_release(struct config_item *item)
{
struct nullb_device *dev = to_nullb_device(item);
null_free_device_storage(dev);
null_free_dev(dev);
}
static struct configfs_item_operations nullb_device_ops = {
.release = nullb_device_release,
};
static 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\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 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 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);
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->use_lightnvm = g_use_lightnvm;
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)
{
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;
t_page->bitmap = 0;
return t_page;
out_freepage:
kfree(t_page);
out:
return NULL;
}
static void null_free_page(struct nullb_page *t_page)
{
__free_page(t_page->page);
kfree(t_page);
}
static void null_free_sector(struct nullb *nullb, sector_t sector)
{
unsigned int sector_bit;
u64 idx;
struct nullb_page *t_page, *ret;
struct radix_tree_root *root;
root = &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 (!t_page->bitmap) {
ret = radix_tree_delete_item(root, idx, t_page);
WARN_ON(ret != t_page);
null_free_page(ret);
}
}
}
static struct nullb_page *null_radix_tree_insert(struct nullb *nullb, u64 idx,
struct nullb_page *t_page)
{
struct radix_tree_root *root;
root = &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);
}
return t_page;
}
static void null_free_device_storage(struct nullb_device *dev)
{
unsigned long pos = 0;
int nr_pages;
struct nullb_page *ret, *t_pages[FREE_BATCH];
struct radix_tree_root *root;
root = &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);
}
static struct nullb_page *null_lookup_page(struct nullb *nullb,
sector_t sector, bool for_write)
{
unsigned int sector_bit;
u64 idx;
struct nullb_page *t_page;
idx = sector >> PAGE_SECTORS_SHIFT;
sector_bit = (sector & SECTOR_MASK);
t_page = radix_tree_lookup(&nullb->dev->data, 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_insert_page(struct nullb *nullb,
sector_t sector)
{
u64 idx;
struct nullb_page *t_page;
t_page = null_lookup_page(nullb, sector, true);
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);
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);
}
static int copy_to_nullb(struct nullb *nullb, struct page *source,
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_insert_page(nullb, sector);
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);
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);
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);
sector += temp >> SECTOR_SHIFT;
n -= temp;
}
spin_unlock_irq(&nullb->lock);
}
static int null_transfer(struct nullb *nullb, struct page *page,
unsigned int len, unsigned int off, bool is_write, sector_t sector)
{
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);
}
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);
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);
if (err) {
spin_unlock_irq(&nullb->lock);
return err;
}
sector += len >> SECTOR_SHIFT;
}
spin_unlock_irq(&nullb->lock);
return 0;
}
static blk_status_t null_handle_cmd(struct nullb_cmd *cmd)
{
struct nullb_device *dev = cmd->nq->dev;
int err = 0;
if (dev->memory_backed) {
if (dev->queue_mode == NULL_Q_BIO)
err = null_handle_bio(cmd);
else
err = null_handle_rq(cmd);
}
cmd->error = errno_to_blk_status(err);
/* 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 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 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 void null_request_fn(struct request_queue *q)
{
struct request *rq;
while ((rq = blk_fetch_request(q)) != NULL) {
struct nullb_cmd *cmd = rq->special;
spin_unlock_irq(q->queue_lock);
null_handle_cmd(cmd);
spin_lock_irq(q->queue_lock);
}
}
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);
return null_handle_cmd(cmd);
}
static const struct blk_mq_ops null_mq_ops = {
.queue_rq = null_queue_rq,
.complete = null_softirq_done_fn,
};
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);
}
#ifdef CONFIG_NVM
static void null_lnvm_end_io(struct request *rq, blk_status_t status)
{
struct nvm_rq *rqd = rq->end_io_data;
/* XXX: lighnvm core seems to expect NVM_RSP_* values here.. */
rqd->error = status ? -EIO : 0;
nvm_end_io(rqd);
blk_put_request(rq);
}
static int null_lnvm_submit_io(struct nvm_dev *dev, struct nvm_rq *rqd)
{
struct request_queue *q = dev->q;
struct request *rq;
struct bio *bio = rqd->bio;
rq = blk_mq_alloc_request(q,
op_is_write(bio_op(bio)) ? REQ_OP_DRV_OUT : REQ_OP_DRV_IN, 0);
if (IS_ERR(rq))
return -ENOMEM;
blk_init_request_from_bio(rq, bio);
rq->end_io_data = rqd;
blk_execute_rq_nowait(q, NULL, rq, 0, null_lnvm_end_io);
return 0;
}
static int null_lnvm_id(struct nvm_dev *dev, struct nvm_id *id)
{
struct nullb *nullb = dev->q->queuedata;
sector_t size = (sector_t)nullb->dev->size * 1024 * 1024ULL;
sector_t blksize;
struct nvm_id_group *grp;
id->ver_id = 0x1;
id->vmnt = 0;
id->cap = 0x2;
id->dom = 0x1;
id->ppaf.blk_offset = 0;
id->ppaf.blk_len = 16;
id->ppaf.pg_offset = 16;
id->ppaf.pg_len = 16;
id->ppaf.sect_offset = 32;
id->ppaf.sect_len = 8;
id->ppaf.pln_offset = 40;
id->ppaf.pln_len = 8;
id->ppaf.lun_offset = 48;
id->ppaf.lun_len = 8;
id->ppaf.ch_offset = 56;
id->ppaf.ch_len = 8;
sector_div(size, nullb->dev->blocksize); /* convert size to pages */
size >>= 8; /* concert size to pgs pr blk */
grp = &id->grp;
grp->mtype = 0;
grp->fmtype = 0;
grp->num_ch = 1;
grp->num_pg = 256;
blksize = size;
size >>= 16;
grp->num_lun = size + 1;
sector_div(blksize, grp->num_lun);
grp->num_blk = blksize;
grp->num_pln = 1;
grp->fpg_sz = nullb->dev->blocksize;
grp->csecs = nullb->dev->blocksize;
grp->trdt = 25000;
grp->trdm = 25000;
grp->tprt = 500000;
grp->tprm = 500000;
grp->tbet = 1500000;
grp->tbem = 1500000;
grp->mpos = 0x010101; /* single plane rwe */
grp->cpar = nullb->dev->hw_queue_depth;
return 0;
}
static void *null_lnvm_create_dma_pool(struct nvm_dev *dev, char *name)
{
mempool_t *virtmem_pool;
virtmem_pool = mempool_create_slab_pool(64, ppa_cache);
if (!virtmem_pool) {
pr_err("null_blk: Unable to create virtual memory pool\n");
return NULL;
}
return virtmem_pool;
}
static void null_lnvm_destroy_dma_pool(void *pool)
{
mempool_destroy(pool);
}
static void *null_lnvm_dev_dma_alloc(struct nvm_dev *dev, void *pool,
gfp_t mem_flags, dma_addr_t *dma_handler)
{
return mempool_alloc(pool, mem_flags);
}
static void null_lnvm_dev_dma_free(void *pool, void *entry,
dma_addr_t dma_handler)
{
mempool_free(entry, pool);
}
static struct nvm_dev_ops null_lnvm_dev_ops = {
.identity = null_lnvm_id,
.submit_io = null_lnvm_submit_io,
.create_dma_pool = null_lnvm_create_dma_pool,
.destroy_dma_pool = null_lnvm_destroy_dma_pool,
.dev_dma_alloc = null_lnvm_dev_dma_alloc,
.dev_dma_free = null_lnvm_dev_dma_free,
/* Simulate nvme protocol restriction */
.max_phys_sect = 64,
};
static int null_nvm_register(struct nullb *nullb)
{
struct nvm_dev *dev;
int rv;
dev = nvm_alloc_dev(0);
if (!dev)
return -ENOMEM;
dev->q = nullb->q;
memcpy(dev->name, nullb->disk_name, DISK_NAME_LEN);
dev->ops = &null_lnvm_dev_ops;
rv = nvm_register(dev);
if (rv) {
kfree(dev);
return rv;
}
nullb->ndev = dev;
return 0;
}
static void null_nvm_unregister(struct nullb *nullb)
{
nvm_unregister(nullb->ndev);
}
#else
static int null_nvm_register(struct nullb *nullb)
{
pr_err("null_blk: CONFIG_NVM needs to be enabled for LightNVM\n");
return -EINVAL;
}
static void null_nvm_unregister(struct nullb *nullb) {}
#endif /* CONFIG_NVM */
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);
if (dev->use_lightnvm)
null_nvm_unregister(nullb);
else
del_gendisk(nullb->disk);
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);
if (!dev->use_lightnvm)
put_disk(nullb->disk);
cleanup_queues(nullb);
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);
queue_flag_set_unlocked(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;
set->driver_data = NULL;
if (nullb->dev->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->use_lightnvm && dev->blocksize != 4096)
dev->blocksize = 4096;
if (dev->use_lightnvm && dev->queue_mode != NULL_Q_MQ)
dev->queue_mode = NULL_Q_MQ;
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;
}
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;
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);
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;
}
blk_queue_prep_rq(nullb->q, null_rq_prep_fn);
blk_queue_softirq_done(nullb->q, null_softirq_done_fn);
rv = init_driver_queues(nullb);
if (rv)
goto out_cleanup_blk_queue;
}
nullb->q->queuedata = nullb;
queue_flag_set_unlocked(QUEUE_FLAG_NONROT, nullb->q);
queue_flag_clear_unlocked(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);
if (dev->use_lightnvm)
rv = null_nvm_register(nullb);
else
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:
null_free_dev(dev);
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_use_lightnvm && g_bs != 4096) {
pr_warn("null_blk: LightNVM only supports 4k block size\n");
pr_warn("null_blk: defaults block size to 4k\n");
g_bs = 4096;
}
if (g_use_lightnvm && g_queue_mode != NULL_Q_MQ) {
pr_warn("null_blk: LightNVM only supported for blk-mq\n");
pr_warn("null_blk: defaults queue mode to blk-mq\n");
g_queue_mode = NULL_Q_MQ;
}
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;
}
if (g_use_lightnvm) {
ppa_cache = kmem_cache_create("ppa_cache", 64 * sizeof(u64),
0, 0, NULL);
if (!ppa_cache) {
pr_err("null_blk: unable to create ppa cache\n");
ret = -ENOMEM;
goto err_ppa;
}
}
for (i = 0; i < nr_devices; i++) {
dev = null_alloc_dev();
if (!dev)
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);
}
kmem_cache_destroy(ppa_cache);
err_ppa:
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);
kmem_cache_destroy(ppa_cache);
}
module_init(null_init);
module_exit(null_exit);
MODULE_AUTHOR("Jens Axboe <jaxboe@fusionio.com>");
MODULE_LICENSE("GPL");