/*
* Copyright (C) 2001, 2002 Sistina Software (UK) Limited.
* Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
*
* This file is released under the GPL.
*/
#include "dm.h"
#include "dm-uevent.h"
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/moduleparam.h>
#include <linux/blkpg.h>
#include <linux/bio.h>
#include <linux/mempool.h>
#include <linux/slab.h>
#include <linux/idr.h>
#include <linux/hdreg.h>
#include <linux/delay.h>
#include <linux/wait.h>
#include <linux/kthread.h>
#include <linux/ktime.h>
#include <linux/elevator.h> /* for rq_end_sector() */
#include <linux/blk-mq.h>
#include <linux/pr.h>
#include <trace/events/block.h>
#define DM_MSG_PREFIX "core"
#ifdef CONFIG_PRINTK
/*
* ratelimit state to be used in DMXXX_LIMIT().
*/
DEFINE_RATELIMIT_STATE(dm_ratelimit_state,
DEFAULT_RATELIMIT_INTERVAL,
DEFAULT_RATELIMIT_BURST);
EXPORT_SYMBOL(dm_ratelimit_state);
#endif
/*
* Cookies are numeric values sent with CHANGE and REMOVE
* uevents while resuming, removing or renaming the device.
*/
#define DM_COOKIE_ENV_VAR_NAME "DM_COOKIE"
#define DM_COOKIE_LENGTH 24
static const char *_name = DM_NAME;
static unsigned int major = 0;
static unsigned int _major = 0;
static DEFINE_IDR(_minor_idr);
static DEFINE_SPINLOCK(_minor_lock);
static void do_deferred_remove(struct work_struct *w);
static DECLARE_WORK(deferred_remove_work, do_deferred_remove);
static struct workqueue_struct *deferred_remove_workqueue;
/*
* For bio-based dm.
* One of these is allocated per bio.
*/
struct dm_io {
struct mapped_device *md;
int error;
atomic_t io_count;
struct bio *bio;
unsigned long start_time;
spinlock_t endio_lock;
struct dm_stats_aux stats_aux;
};
/*
* For request-based dm.
* One of these is allocated per request.
*/
struct dm_rq_target_io {
struct mapped_device *md;
struct dm_target *ti;
struct request *orig, *clone;
struct kthread_work work;
int error;
union map_info info;
struct dm_stats_aux stats_aux;
unsigned long duration_jiffies;
unsigned n_sectors;
};
/*
* For request-based dm - the bio clones we allocate are embedded in these
* structs.
*
* We allocate these with bio_alloc_bioset, using the front_pad parameter when
* the bioset is created - this means the bio has to come at the end of the
* struct.
*/
struct dm_rq_clone_bio_info {
struct bio *orig;
struct dm_rq_target_io *tio;
struct bio clone;
};
union map_info *dm_get_rq_mapinfo(struct request *rq)
{
if (rq && rq->end_io_data)
return &((struct dm_rq_target_io *)rq->end_io_data)->info;
return NULL;
}
EXPORT_SYMBOL_GPL(dm_get_rq_mapinfo);
#define MINOR_ALLOCED ((void *)-1)
/*
* Bits for the md->flags field.
*/
#define DMF_BLOCK_IO_FOR_SUSPEND 0
#define DMF_SUSPENDED 1
#define DMF_FROZEN 2
#define DMF_FREEING 3
#define DMF_DELETING 4
#define DMF_NOFLUSH_SUSPENDING 5
#define DMF_DEFERRED_REMOVE 6
#define DMF_SUSPENDED_INTERNALLY 7
/*
* A dummy definition to make RCU happy.
* struct dm_table should never be dereferenced in this file.
*/
struct dm_table {
int undefined__;
};
/*
* Work processed by per-device workqueue.
*/
struct mapped_device {
struct srcu_struct io_barrier;
struct mutex suspend_lock;
atomic_t holders;
atomic_t open_count;
/*
* The current mapping.
* Use dm_get_live_table{_fast} or take suspend_lock for
* dereference.
*/
struct dm_table __rcu *map;
struct list_head table_devices;
struct mutex table_devices_lock;
unsigned long flags;
struct request_queue *queue;
unsigned type;
/* Protect queue and type against concurrent access. */
struct mutex type_lock;
struct target_type *immutable_target_type;
struct gendisk *disk;
char name[16];
void *interface_ptr;
/*
* A list of ios that arrived while we were suspended.
*/
atomic_t pending[2];
wait_queue_head_t wait;
struct work_struct work;
struct bio_list deferred;
spinlock_t deferred_lock;
/*
* Processing queue (flush)
*/
struct workqueue_struct *wq;
/*
* io objects are allocated from here.
*/
mempool_t *io_pool;
mempool_t *rq_pool;
struct bio_set *bs;
/*
* Event handling.
*/
atomic_t event_nr;
wait_queue_head_t eventq;
atomic_t uevent_seq;
struct list_head uevent_list;
spinlock_t uevent_lock; /* Protect access to uevent_list */
/*
* freeze/thaw support require holding onto a super block
*/
struct super_block *frozen_sb;
struct block_device *bdev;
/* forced geometry settings */
struct hd_geometry geometry;
/* kobject and completion */
struct dm_kobject_holder kobj_holder;
/* zero-length flush that will be cloned and submitted to targets */
struct bio flush_bio;
/* the number of internal suspends */
unsigned internal_suspend_count;
struct dm_stats stats;
struct kthread_worker kworker;
struct task_struct *kworker_task;
/* for request-based merge heuristic in dm_request_fn() */
unsigned seq_rq_merge_deadline_usecs;
int last_rq_rw;
sector_t last_rq_pos;
ktime_t last_rq_start_time;
/* for blk-mq request-based DM support */
struct blk_mq_tag_set tag_set;
bool use_blk_mq;
};
#ifdef CONFIG_DM_MQ_DEFAULT
static bool use_blk_mq = true;
#else
static bool use_blk_mq = false;
#endif
bool dm_use_blk_mq(struct mapped_device *md)
{
return md->use_blk_mq;
}
/*
* For mempools pre-allocation at the table loading time.
*/
struct dm_md_mempools {
mempool_t *io_pool;
mempool_t *rq_pool;
struct bio_set *bs;
};
struct table_device {
struct list_head list;
atomic_t count;
struct dm_dev dm_dev;
};
#define RESERVED_BIO_BASED_IOS 16
#define RESERVED_REQUEST_BASED_IOS 256
#define RESERVED_MAX_IOS 1024
static struct kmem_cache *_io_cache;
static struct kmem_cache *_rq_tio_cache;
static struct kmem_cache *_rq_cache;
/*
* Bio-based DM's mempools' reserved IOs set by the user.
*/
static unsigned reserved_bio_based_ios = RESERVED_BIO_BASED_IOS;
/*
* Request-based DM's mempools' reserved IOs set by the user.
*/
static unsigned reserved_rq_based_ios = RESERVED_REQUEST_BASED_IOS;
static unsigned __dm_get_module_param(unsigned *module_param,
unsigned def, unsigned max)
{
unsigned param = ACCESS_ONCE(*module_param);
unsigned modified_param = 0;
if (!param)
modified_param = def;
else if (param > max)
modified_param = max;
if (modified_param) {
(void)cmpxchg(module_param, param, modified_param);
param = modified_param;
}
return param;
}
unsigned dm_get_reserved_bio_based_ios(void)
{
return __dm_get_module_param(&reserved_bio_based_ios,
RESERVED_BIO_BASED_IOS, RESERVED_MAX_IOS);
}
EXPORT_SYMBOL_GPL(dm_get_reserved_bio_based_ios);
unsigned dm_get_reserved_rq_based_ios(void)
{
return __dm_get_module_param(&reserved_rq_based_ios,
RESERVED_REQUEST_BASED_IOS, RESERVED_MAX_IOS);
}
EXPORT_SYMBOL_GPL(dm_get_reserved_rq_based_ios);
static int __init local_init(void)
{
int r = -ENOMEM;
/* allocate a slab for the dm_ios */
_io_cache = KMEM_CACHE(dm_io, 0);
if (!_io_cache)
return r;
_rq_tio_cache = KMEM_CACHE(dm_rq_target_io, 0);
if (!_rq_tio_cache)
goto out_free_io_cache;
_rq_cache = kmem_cache_create("dm_clone_request", sizeof(struct request),
__alignof__(struct request), 0, NULL);
if (!_rq_cache)
goto out_free_rq_tio_cache;
r = dm_uevent_init();
if (r)
goto out_free_rq_cache;
deferred_remove_workqueue = alloc_workqueue("kdmremove", WQ_UNBOUND, 1);
if (!deferred_remove_workqueue) {
r = -ENOMEM;
goto out_uevent_exit;
}
_major = major;
r = register_blkdev(_major, _name);
if (r < 0)
goto out_free_workqueue;
if (!_major)
_major = r;
return 0;
out_free_workqueue:
destroy_workqueue(deferred_remove_workqueue);
out_uevent_exit:
dm_uevent_exit();
out_free_rq_cache:
kmem_cache_destroy(_rq_cache);
out_free_rq_tio_cache:
kmem_cache_destroy(_rq_tio_cache);
out_free_io_cache:
kmem_cache_destroy(_io_cache);
return r;
}
static void local_exit(void)
{
flush_scheduled_work();
destroy_workqueue(deferred_remove_workqueue);
kmem_cache_destroy(_rq_cache);
kmem_cache_destroy(_rq_tio_cache);
kmem_cache_destroy(_io_cache);
unregister_blkdev(_major, _name);
dm_uevent_exit();
_major = 0;
DMINFO("cleaned up");
}
static int (*_inits[])(void) __initdata = {
local_init,
dm_target_init,
dm_linear_init,
dm_stripe_init,
dm_io_init,
dm_kcopyd_init,
dm_interface_init,
dm_statistics_init,
};
static void (*_exits[])(void) = {
local_exit,
dm_target_exit,
dm_linear_exit,
dm_stripe_exit,
dm_io_exit,
dm_kcopyd_exit,
dm_interface_exit,
dm_statistics_exit,
};
static int __init dm_init(void)
{
const int count = ARRAY_SIZE(_inits);
int r, i;
for (i = 0; i < count; i++) {
r = _inits[i]();
if (r)
goto bad;
}
return 0;
bad:
while (i--)
_exits[i]();
return r;
}
static void __exit dm_exit(void)
{
int i = ARRAY_SIZE(_exits);
while (i--)
_exits[i]();
/*
* Should be empty by this point.
*/
idr_destroy(&_minor_idr);
}
/*
* Block device functions
*/
int dm_deleting_md(struct mapped_device *md)
{
return test_bit(DMF_DELETING, &md->flags);
}
static int dm_blk_open(struct block_device *bdev, fmode_t mode)
{
struct mapped_device *md;
spin_lock(&_minor_lock);
md = bdev->bd_disk->private_data;
if (!md)
goto out;
if (test_bit(DMF_FREEING, &md->flags) ||
dm_deleting_md(md)) {
md = NULL;
goto out;
}
dm_get(md);
atomic_inc(&md->open_count);
out:
spin_unlock(&_minor_lock);
return md ? 0 : -ENXIO;
}
static void dm_blk_close(struct gendisk *disk, fmode_t mode)
{
struct mapped_device *md;
spin_lock(&_minor_lock);
md = disk->private_data;
if (WARN_ON(!md))
goto out;
if (atomic_dec_and_test(&md->open_count) &&
(test_bit(DMF_DEFERRED_REMOVE, &md->flags)))
queue_work(deferred_remove_workqueue, &deferred_remove_work);
dm_put(md);
out:
spin_unlock(&_minor_lock);
}
int dm_open_count(struct mapped_device *md)
{
return atomic_read(&md->open_count);
}
/*
* Guarantees nothing is using the device before it's deleted.
*/
int dm_lock_for_deletion(struct mapped_device *md, bool mark_deferred, bool only_deferred)
{
int r = 0;
spin_lock(&_minor_lock);
if (dm_open_count(md)) {
r = -EBUSY;
if (mark_deferred)
set_bit(DMF_DEFERRED_REMOVE, &md->flags);
} else if (only_deferred && !test_bit(DMF_DEFERRED_REMOVE, &md->flags))
r = -EEXIST;
else
set_bit(DMF_DELETING, &md->flags);
spin_unlock(&_minor_lock);
return r;
}
int dm_cancel_deferred_remove(struct mapped_device *md)
{
int r = 0;
spin_lock(&_minor_lock);
if (test_bit(DMF_DELETING, &md->flags))
r = -EBUSY;
else
clear_bit(DMF_DEFERRED_REMOVE, &md->flags);
spin_unlock(&_minor_lock);
return r;
}
static void do_deferred_remove(struct work_struct *w)
{
dm_deferred_remove();
}
sector_t dm_get_size(struct mapped_device *md)
{
return get_capacity(md->disk);
}
struct request_queue *dm_get_md_queue(struct mapped_device *md)
{
return md->queue;
}
struct dm_stats *dm_get_stats(struct mapped_device *md)
{
return &md->stats;
}
static int dm_blk_getgeo(struct block_device *bdev, struct hd_geometry *geo)
{
struct mapped_device *md = bdev->bd_disk->private_data;
return dm_get_geometry(md, geo);
}
static int dm_get_live_table_for_ioctl(struct mapped_device *md,
struct dm_target **tgt, struct block_device **bdev,
fmode_t *mode, int *srcu_idx)
{
struct dm_table *map;
int r;
retry:
r = -ENOTTY;
map = dm_get_live_table(md, srcu_idx);
if (!map || !dm_table_get_size(map))
goto out;
/* We only support devices that have a single target */
if (dm_table_get_num_targets(map) != 1)
goto out;
*tgt = dm_table_get_target(map, 0);
if (!(*tgt)->type->prepare_ioctl)
goto out;
if (dm_suspended_md(md)) {
r = -EAGAIN;
goto out;
}
r = (*tgt)->type->prepare_ioctl(*tgt, bdev, mode);
if (r < 0)
goto out;
return r;
out:
dm_put_live_table(md, *srcu_idx);
if (r == -ENOTCONN && !fatal_signal_pending(current)) {
msleep(10);
goto retry;
}
return r;
}
static int dm_blk_ioctl(struct block_device *bdev, fmode_t mode,
unsigned int cmd, unsigned long arg)
{
struct mapped_device *md = bdev->bd_disk->private_data;
struct dm_target *tgt;
struct block_device *tgt_bdev = NULL;
int srcu_idx, r;
r = dm_get_live_table_for_ioctl(md, &tgt, &tgt_bdev, &mode, &srcu_idx);
if (r < 0)
return r;
if (r > 0) {
/*
* Target determined this ioctl is being issued against
* a logical partition of the parent bdev; so extra
* validation is needed.
*/
r = scsi_verify_blk_ioctl(NULL, cmd);
if (r)
goto out;
}
r = __blkdev_driver_ioctl(tgt_bdev, mode, cmd, arg);
out:
dm_put_live_table(md, srcu_idx);
return r;
}
static struct dm_io *alloc_io(struct mapped_device *md)
{
return mempool_alloc(md->io_pool, GFP_NOIO);
}
static void free_io(struct mapped_device *md, struct dm_io *io)
{
mempool_free(io, md->io_pool);
}
static void free_tio(struct mapped_device *md, struct dm_target_io *tio)
{
bio_put(&tio->clone);
}
static struct dm_rq_target_io *alloc_rq_tio(struct mapped_device *md,
gfp_t gfp_mask)
{
return mempool_alloc(md->io_pool, gfp_mask);
}
static void free_rq_tio(struct dm_rq_target_io *tio)
{
mempool_free(tio, tio->md->io_pool);
}
static struct request *alloc_clone_request(struct mapped_device *md,
gfp_t gfp_mask)
{
return mempool_alloc(md->rq_pool, gfp_mask);
}
static void free_clone_request(struct mapped_device *md, struct request *rq)
{
mempool_free(rq, md->rq_pool);
}
static int md_in_flight(struct mapped_device *md)
{
return atomic_read(&md->pending[READ]) +
atomic_read(&md->pending[WRITE]);
}
static void start_io_acct(struct dm_io *io)
{
struct mapped_device *md = io->md;
struct bio *bio = io->bio;
int cpu;
int rw = bio_data_dir(bio);
io->start_time = jiffies;
cpu = part_stat_lock();
part_round_stats(cpu, &dm_disk(md)->part0);
part_stat_unlock();
atomic_set(&dm_disk(md)->part0.in_flight[rw],
atomic_inc_return(&md->pending[rw]));
if (unlikely(dm_stats_used(&md->stats)))
dm_stats_account_io(&md->stats, bio->bi_rw, bio->bi_iter.bi_sector,
bio_sectors(bio), false, 0, &io->stats_aux);
}
static void end_io_acct(struct dm_io *io)
{
struct mapped_device *md = io->md;
struct bio *bio = io->bio;
unsigned long duration = jiffies - io->start_time;
int pending;
int rw = bio_data_dir(bio);
generic_end_io_acct(rw, &dm_disk(md)->part0, io->start_time);
if (unlikely(dm_stats_used(&md->stats)))
dm_stats_account_io(&md->stats, bio->bi_rw, bio->bi_iter.bi_sector,
bio_sectors(bio), true, duration, &io->stats_aux);
/*
* After this is decremented the bio must not be touched if it is
* a flush.
*/
pending = atomic_dec_return(&md->pending[rw]);
atomic_set(&dm_disk(md)->part0.in_flight[rw], pending);
pending += atomic_read(&md->pending[rw^0x1]);
/* nudge anyone waiting on suspend queue */
if (!pending)
wake_up(&md->wait);
}
/*
* Add the bio to the list of deferred io.
*/
static void queue_io(struct mapped_device *md, struct bio *bio)
{
unsigned long flags;
spin_lock_irqsave(&md->deferred_lock, flags);
bio_list_add(&md->deferred, bio);
spin_unlock_irqrestore(&md->deferred_lock, flags);
queue_work(md->wq, &md->work);
}
/*
* Everyone (including functions in this file), should use this
* function to access the md->map field, and make sure they call
* dm_put_live_table() when finished.
*/
struct dm_table *dm_get_live_table(struct mapped_device *md, int *srcu_idx) __acquires(md->io_barrier)
{
*srcu_idx = srcu_read_lock(&md->io_barrier);
return srcu_dereference(md->map, &md->io_barrier);
}
void dm_put_live_table(struct mapped_device *md, int srcu_idx) __releases(md->io_barrier)
{
srcu_read_unlock(&md->io_barrier, srcu_idx);
}
void dm_sync_table(struct mapped_device *md)
{
synchronize_srcu(&md->io_barrier);
synchronize_rcu_expedited();
}
/*
* A fast alternative to dm_get_live_table/dm_put_live_table.
* The caller must not block between these two functions.
*/
static struct dm_table *dm_get_live_table_fast(struct mapped_device *md) __acquires(RCU)
{
rcu_read_lock();
return rcu_dereference(md->map);
}
static void dm_put_live_table_fast(struct mapped_device *md) __releases(RCU)
{
rcu_read_unlock();
}
/*
* Open a table device so we can use it as a map destination.
*/
static int open_table_device(struct table_device *td, dev_t dev,
struct mapped_device *md)
{
static char *_claim_ptr = "I belong to device-mapper";
struct block_device *bdev;
int r;
BUG_ON(td->dm_dev.bdev);
bdev = blkdev_get_by_dev(dev, td->dm_dev.mode | FMODE_EXCL, _claim_ptr);
if (IS_ERR(bdev))
return PTR_ERR(bdev);
r = bd_link_disk_holder(bdev, dm_disk(md));
if (r) {
blkdev_put(bdev, td->dm_dev.mode | FMODE_EXCL);
return r;
}
td->dm_dev.bdev = bdev;
return 0;
}
/*
* Close a table device that we've been using.
*/
static void close_table_device(struct table_device *td, struct mapped_device *md)
{
if (!td->dm_dev.bdev)
return;
bd_unlink_disk_holder(td->dm_dev.bdev, dm_disk(md));
blkdev_put(td->dm_dev.bdev, td->dm_dev.mode | FMODE_EXCL);
td->dm_dev.bdev = NULL;
}
static struct table_device *find_table_device(struct list_head *l, dev_t dev,
fmode_t mode) {
struct table_device *td;
list_for_each_entry(td, l, list)
if (td->dm_dev.bdev->bd_dev == dev && td->dm_dev.mode == mode)
return td;
return NULL;
}
int dm_get_table_device(struct mapped_device *md, dev_t dev, fmode_t mode,
struct dm_dev **result) {
int r;
struct table_device *td;
mutex_lock(&md->table_devices_lock);
td = find_table_device(&md->table_devices, dev, mode);
if (!td) {
td = kmalloc(sizeof(*td), GFP_KERNEL);
if (!td) {
mutex_unlock(&md->table_devices_lock);
return -ENOMEM;
}
td->dm_dev.mode = mode;
td->dm_dev.bdev = NULL;
if ((r = open_table_device(td, dev, md))) {
mutex_unlock(&md->table_devices_lock);
kfree(td);
return r;
}
format_dev_t(td->dm_dev.name, dev);
atomic_set(&td->count, 0);
list_add(&td->list, &md->table_devices);
}
atomic_inc(&td->count);
mutex_unlock(&md->table_devices_lock);
*result = &td->dm_dev;
return 0;
}
EXPORT_SYMBOL_GPL(dm_get_table_device);
void dm_put_table_device(struct mapped_device *md, struct dm_dev *d)
{
struct table_device *td = container_of(d, struct table_device, dm_dev);
mutex_lock(&md->table_devices_lock);
if (atomic_dec_and_test(&td->count)) {
close_table_device(td, md);
list_del(&td->list);
kfree(td);
}
mutex_unlock(&md->table_devices_lock);
}
EXPORT_SYMBOL(dm_put_table_device);
static void free_table_devices(struct list_head *devices)
{
struct list_head *tmp, *next;
list_for_each_safe(tmp, next, devices) {
struct table_device *td = list_entry(tmp, struct table_device, list);
DMWARN("dm_destroy: %s still exists with %d references",
td->dm_dev.name, atomic_read(&td->count));
kfree(td);
}
}
/*
* Get the geometry associated with a dm device
*/
int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo)
{
*geo = md->geometry;
return 0;
}
/*
* Set the geometry of a device.
*/
int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo)
{
sector_t sz = (sector_t)geo->cylinders * geo->heads * geo->sectors;
if (geo->start > sz) {
DMWARN("Start sector is beyond the geometry limits.");
return -EINVAL;
}
md->geometry = *geo;
return 0;
}
/*-----------------------------------------------------------------
* CRUD START:
* A more elegant soln is in the works that uses the queue
* merge fn, unfortunately there are a couple of changes to
* the block layer that I want to make for this. So in the
* interests of getting something for people to use I give
* you this clearly demarcated crap.
*---------------------------------------------------------------*/
static int __noflush_suspending(struct mapped_device *md)
{
return test_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
}
/*
* Decrements the number of outstanding ios that a bio has been
* cloned into, completing the original io if necc.
*/
static void dec_pending(struct dm_io *io, int error)
{
unsigned long flags;
int io_error;
struct bio *bio;
struct mapped_device *md = io->md;
/* Push-back supersedes any I/O errors */
if (unlikely(error)) {
spin_lock_irqsave(&io->endio_lock, flags);
if (!(io->error > 0 && __noflush_suspending(md)))
io->error = error;
spin_unlock_irqrestore(&io->endio_lock, flags);
}
if (atomic_dec_and_test(&io->io_count)) {
if (io->error == DM_ENDIO_REQUEUE) {
/*
* Target requested pushing back the I/O.
*/
spin_lock_irqsave(&md->deferred_lock, flags);
if (__noflush_suspending(md))
bio_list_add_head(&md->deferred, io->bio);
else
/* noflush suspend was interrupted. */
io->error = -EIO;
spin_unlock_irqrestore(&md->deferred_lock, flags);
}
io_error = io->error;
bio = io->bio;
end_io_acct(io);
free_io(md, io);
if (io_error == DM_ENDIO_REQUEUE)
return;
if ((bio->bi_rw & REQ_FLUSH) && bio->bi_iter.bi_size) {
/*
* Preflush done for flush with data, reissue
* without REQ_FLUSH.
*/
bio->bi_rw &= ~REQ_FLUSH;
queue_io(md, bio);
} else {
/* done with normal IO or empty flush */
trace_block_bio_complete(md->queue, bio, io_error);
bio->bi_error = io_error;
bio_endio(bio);
}
}
}
static void disable_write_same(struct mapped_device *md)
{
struct queue_limits *limits = dm_get_queue_limits(md);
/* device doesn't really support WRITE SAME, disable it */
limits->max_write_same_sectors = 0;
}
static void clone_endio(struct bio *bio)
{
int error = bio->bi_error;
int r = error;
struct dm_target_io *tio = container_of(bio, struct dm_target_io, clone);
struct dm_io *io = tio->io;
struct mapped_device *md = tio->io->md;
dm_endio_fn endio = tio->ti->type->end_io;
if (endio) {
r = endio(tio->ti, bio, error);
if (r < 0 || r == DM_ENDIO_REQUEUE)
/*
* error and requeue request are handled
* in dec_pending().
*/
error = r;
else if (r == DM_ENDIO_INCOMPLETE)
/* The target will handle the io */
return;
else if (r) {
DMWARN("unimplemented target endio return value: %d", r);
BUG();
}
}
if (unlikely(r == -EREMOTEIO && (bio->bi_rw & REQ_WRITE_SAME) &&
!bdev_get_queue(bio->bi_bdev)->limits.max_write_same_sectors))
disable_write_same(md);
free_tio(md, tio);
dec_pending(io, error);
}
/*
* Partial completion handling for request-based dm
*/
static void end_clone_bio(struct bio *clone)
{
struct dm_rq_clone_bio_info *info =
container_of(clone, struct dm_rq_clone_bio_info, clone);
struct dm_rq_target_io *tio = info->tio;
struct bio *bio = info->orig;
unsigned int nr_bytes = info->orig->bi_iter.bi_size;
int error = clone->bi_error;
bio_put(clone);
if (tio->error)
/*
* An error has already been detected on the request.
* Once error occurred, just let clone->end_io() handle
* the remainder.
*/
return;
else if (error) {
/*
* Don't notice the error to the upper layer yet.
* The error handling decision is made by the target driver,
* when the request is completed.
*/
tio->error = error;
return;
}
/*
* I/O for the bio successfully completed.
* Notice the data completion to the upper layer.
*/
/*
* bios are processed from the head of the list.
* So the completing bio should always be rq->bio.
* If it's not, something wrong is happening.
*/
if (tio->orig->bio != bio)
DMERR("bio completion is going in the middle of the request");
/*
* Update the original request.
* Do not use blk_end_request() here, because it may complete
* the original request before the clone, and break the ordering.
*/
blk_update_request(tio->orig, 0, nr_bytes);
}
static struct dm_rq_target_io *tio_from_request(struct request *rq)
{
return (rq->q->mq_ops ? blk_mq_rq_to_pdu(rq) : rq->special);
}
static void rq_end_stats(struct mapped_device *md, struct request *orig)
{
if (unlikely(dm_stats_used(&md->stats))) {
struct dm_rq_target_io *tio = tio_from_request(orig);
tio->duration_jiffies = jiffies - tio->duration_jiffies;
dm_stats_account_io(&md->stats, orig->cmd_flags, blk_rq_pos(orig),
tio->n_sectors, true, tio->duration_jiffies,
&tio->stats_aux);
}
}
/*
* Don't touch any member of the md after calling this function because
* the md may be freed in dm_put() at the end of this function.
* Or do dm_get() before calling this function and dm_put() later.
*/
static void rq_completed(struct mapped_device *md, int rw, bool run_queue)
{
atomic_dec(&md->pending[rw]);
/* nudge anyone waiting on suspend queue */
if (!md_in_flight(md))
wake_up(&md->wait);
/*
* Run this off this callpath, as drivers could invoke end_io while
* inside their request_fn (and holding the queue lock). Calling
* back into ->request_fn() could deadlock attempting to grab the
* queue lock again.
*/
if (run_queue) {
if (md->queue->mq_ops)
blk_mq_run_hw_queues(md->queue, true);
else
blk_run_queue_async(md->queue);
}
/*
* dm_put() must be at the end of this function. See the comment above
*/
dm_put(md);
}
static void free_rq_clone(struct request *clone)
{
struct dm_rq_target_io *tio = clone->end_io_data;
struct mapped_device *md = tio->md;
blk_rq_unprep_clone(clone);
if (md->type == DM_TYPE_MQ_REQUEST_BASED)
/* stacked on blk-mq queue(s) */
tio->ti->type->release_clone_rq(clone);
else if (!md->queue->mq_ops)
/* request_fn queue stacked on request_fn queue(s) */
free_clone_request(md, clone);
/*
* NOTE: for the blk-mq queue stacked on request_fn queue(s) case:
* no need to call free_clone_request() because we leverage blk-mq by
* allocating the clone at the end of the blk-mq pdu (see: clone_rq)
*/
if (!md->queue->mq_ops)
free_rq_tio(tio);
}
/*
* Complete the clone and the original request.
* Must be called without clone's queue lock held,
* see end_clone_request() for more details.
*/
static void dm_end_request(struct request *clone, int error)
{
int rw = rq_data_dir(clone);
struct dm_rq_target_io *tio = clone->end_io_data;
struct mapped_device *md = tio->md;
struct request *rq = tio->orig;
if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
rq->errors = clone->errors;
rq->resid_len = clone->resid_len;
if (rq->sense)
/*
* We are using the sense buffer of the original
* request.
* So setting the length of the sense data is enough.
*/
rq->sense_len = clone->sense_len;
}
free_rq_clone(clone);
rq_end_stats(md, rq);
if (!rq->q->mq_ops)
blk_end_request_all(rq, error);
else
blk_mq_end_request(rq, error);
rq_completed(md, rw, true);
}
static void dm_unprep_request(struct request *rq)
{
struct dm_rq_target_io *tio = tio_from_request(rq);
struct request *clone = tio->clone;
if (!rq->q->mq_ops) {
rq->special = NULL;
rq->cmd_flags &= ~REQ_DONTPREP;
}
if (clone)
free_rq_clone(clone);
}
/*
* Requeue the original request of a clone.
*/
static void old_requeue_request(struct request *rq)
{
struct request_queue *q = rq->q;
unsigned long flags;
spin_lock_irqsave(q->queue_lock, flags);
blk_requeue_request(q, rq);
blk_run_queue_async(q);
spin_unlock_irqrestore(q->queue_lock, flags);
}
static void dm_requeue_original_request(struct mapped_device *md,
struct request *rq)
{
int rw = rq_data_dir(rq);
dm_unprep_request(rq);
rq_end_stats(md, rq);
if (!rq->q->mq_ops)
old_requeue_request(rq);
else {
blk_mq_requeue_request(rq);
blk_mq_kick_requeue_list(rq->q);
}
rq_completed(md, rw, false);
}
static void old_stop_queue(struct request_queue *q)
{
unsigned long flags;
if (blk_queue_stopped(q))
return;
spin_lock_irqsave(q->queue_lock, flags);
blk_stop_queue(q);
spin_unlock_irqrestore(q->queue_lock, flags);
}
static void stop_queue(struct request_queue *q)
{
if (!q->mq_ops)
old_stop_queue(q);
else
blk_mq_stop_hw_queues(q);
}
static void old_start_queue(struct request_queue *q)
{
unsigned long flags;
spin_lock_irqsave(q->queue_lock, flags);
if (blk_queue_stopped(q))
blk_start_queue(q);
spin_unlock_irqrestore(q->queue_lock, flags);
}
static void start_queue(struct request_queue *q)
{
if (!q->mq_ops)
old_start_queue(q);
else
blk_mq_start_stopped_hw_queues(q, true);
}
static void dm_done(struct request *clone, int error, bool mapped)
{
int r = error;
struct dm_rq_target_io *tio = clone->end_io_data;
dm_request_endio_fn rq_end_io = NULL;
if (tio->ti) {
rq_end_io = tio->ti->type->rq_end_io;
if (mapped && rq_end_io)
r = rq_end_io(tio->ti, clone, error, &tio->info);
}
if (unlikely(r == -EREMOTEIO && (clone->cmd_flags & REQ_WRITE_SAME) &&
!clone->q->limits.max_write_same_sectors))
disable_write_same(tio->md);
if (r <= 0)
/* The target wants to complete the I/O */
dm_end_request(clone, r);
else if (r == DM_ENDIO_INCOMPLETE)
/* The target will handle the I/O */
return;
else if (r == DM_ENDIO_REQUEUE)
/* The target wants to requeue the I/O */
dm_requeue_original_request(tio->md, tio->orig);
else {
DMWARN("unimplemented target endio return value: %d", r);
BUG();
}
}
/*
* Request completion handler for request-based dm
*/
static void dm_softirq_done(struct request *rq)
{
bool mapped = true;
struct dm_rq_target_io *tio = tio_from_request(rq);
struct request *clone = tio->clone;
int rw;
if (!clone) {
rq_end_stats(tio->md, rq);
rw = rq_data_dir(rq);
if (!rq->q->mq_ops) {
blk_end_request_all(rq, tio->error);
rq_completed(tio->md, rw, false);
free_rq_tio(tio);
} else {
blk_mq_end_request(rq, tio->error);
rq_completed(tio->md, rw, false);
}
return;
}
if (rq->cmd_flags & REQ_FAILED)
mapped = false;
dm_done(clone, tio->error, mapped);
}
/*
* Complete the clone and the original request with the error status
* through softirq context.
*/
static void dm_complete_request(struct request *rq, int error)
{
struct dm_rq_target_io *tio = tio_from_request(rq);
tio->error = error;
blk_complete_request(rq);
}
/*
* Complete the not-mapped clone and the original request with the error status
* through softirq context.
* Target's rq_end_io() function isn't called.
* This may be used when the target's map_rq() or clone_and_map_rq() functions fail.
*/
static void dm_kill_unmapped_request(struct request *rq, int error)
{
rq->cmd_flags |= REQ_FAILED;
dm_complete_request(rq, error);
}
/*
* Called with the clone's queue lock held (for non-blk-mq)
*/
static void end_clone_request(struct request *clone, int error)
{
struct dm_rq_target_io *tio = clone->end_io_data;
if (!clone->q->mq_ops) {
/*
* For just cleaning up the information of the queue in which
* the clone was dispatched.
* The clone is *NOT* freed actually here because it is alloced
* from dm own mempool (REQ_ALLOCED isn't set).
*/
__blk_put_request(clone->q, clone);
}
/*
* Actual request completion is done in a softirq context which doesn't
* hold the clone's queue lock. Otherwise, deadlock could occur because:
* - another request may be submitted by the upper level driver
* of the stacking during the completion
* - the submission which requires queue lock may be done
* against this clone's queue
*/
dm_complete_request(tio->orig, error);
}
/*
* Return maximum size of I/O possible at the supplied sector up to the current
* target boundary.
*/
static sector_t max_io_len_target_boundary(sector_t sector, struct dm_target *ti)
{
sector_t target_offset = dm_target_offset(ti, sector);
return ti->len - target_offset;
}
static sector_t max_io_len(sector_t sector, struct dm_target *ti)
{
sector_t len = max_io_len_target_boundary(sector, ti);
sector_t offset, max_len;
/*
* Does the target need to split even further?
*/
if (ti->max_io_len) {
offset = dm_target_offset(ti, sector);
if (unlikely(ti->max_io_len & (ti->max_io_len - 1)))
max_len = sector_div(offset, ti->max_io_len);
else
max_len = offset & (ti->max_io_len - 1);
max_len = ti->max_io_len - max_len;
if (len > max_len)
len = max_len;
}
return len;
}
int dm_set_target_max_io_len(struct dm_target *ti, sector_t len)
{
if (len > UINT_MAX) {
DMERR("Specified maximum size of target IO (%llu) exceeds limit (%u)",
(unsigned long long)len, UINT_MAX);
ti->error = "Maximum size of target IO is too large";
return -EINVAL;
}
ti->max_io_len = (uint32_t) len;
return 0;
}
EXPORT_SYMBOL_GPL(dm_set_target_max_io_len);
/*
* A target may call dm_accept_partial_bio only from the map routine. It is
* allowed for all bio types except REQ_FLUSH.
*
* dm_accept_partial_bio informs the dm that the target only wants to process
* additional n_sectors sectors of the bio and the rest of the data should be
* sent in a next bio.
*
* A diagram that explains the arithmetics:
* +--------------------+---------------+-------+
* | 1 | 2 | 3 |
* +--------------------+---------------+-------+
*
* <-------------- *tio->len_ptr --------------->
* <------- bi_size ------->
* <-- n_sectors -->
*
* Region 1 was already iterated over with bio_advance or similar function.
* (it may be empty if the target doesn't use bio_advance)
* Region 2 is the remaining bio size that the target wants to process.
* (it may be empty if region 1 is non-empty, although there is no reason
* to make it empty)
* The target requires that region 3 is to be sent in the next bio.
*
* If the target wants to receive multiple copies of the bio (via num_*bios, etc),
* the partially processed part (the sum of regions 1+2) must be the same for all
* copies of the bio.
*/
void dm_accept_partial_bio(struct bio *bio, unsigned n_sectors)
{
struct dm_target_io *tio = container_of(bio, struct dm_target_io, clone);
unsigned bi_size = bio->bi_iter.bi_size >> SECTOR_SHIFT;
BUG_ON(bio->bi_rw & REQ_FLUSH);
BUG_ON(bi_size > *tio->len_ptr);
BUG_ON(n_sectors > bi_size);
*tio->len_ptr -= bi_size - n_sectors;
bio->bi_iter.bi_size = n_sectors << SECTOR_SHIFT;
}
EXPORT_SYMBOL_GPL(dm_accept_partial_bio);
static void __map_bio(struct dm_target_io *tio)
{
int r;
sector_t sector;
struct mapped_device *md;
struct bio *clone = &tio->clone;
struct dm_target *ti = tio->ti;
clone->bi_end_io = clone_endio;
/*
* Map the clone. If r == 0 we don't need to do
* anything, the target has assumed ownership of
* this io.
*/
atomic_inc(&tio->io->io_count);
sector = clone->bi_iter.bi_sector;
r = ti->type->map(ti, clone);
if (r == DM_MAPIO_REMAPPED) {
/* the bio has been remapped so dispatch it */
trace_block_bio_remap(bdev_get_queue(clone->bi_bdev), clone,
tio->io->bio->bi_bdev->bd_dev, sector);
generic_make_request(clone);
} else if (r < 0 || r == DM_MAPIO_REQUEUE) {
/* error the io and bail out, or requeue it if needed */
md = tio->io->md;
dec_pending(tio->io, r);
free_tio(md, tio);
} else if (r != DM_MAPIO_SUBMITTED) {
DMWARN("unimplemented target map return value: %d", r);
BUG();
}
}
struct clone_info {
struct mapped_device *md;
struct dm_table *map;
struct bio *bio;
struct dm_io *io;
sector_t sector;
unsigned sector_count;
};
static void bio_setup_sector(struct bio *bio, sector_t sector, unsigned len)
{
bio->bi_iter.bi_sector = sector;
bio->bi_iter.bi_size = to_bytes(len);
}
/*
* Creates a bio that consists of range of complete bvecs.
*/
static void clone_bio(struct dm_target_io *tio, struct bio *bio,
sector_t sector, unsigned len)
{
struct bio *clone = &tio->clone;
__bio_clone_fast(clone, bio);
if (bio_integrity(bio))
bio_integrity_clone(clone, bio, GFP_NOIO);
bio_advance(clone, to_bytes(sector - clone->bi_iter.bi_sector));
clone->bi_iter.bi_size = to_bytes(len);
if (bio_integrity(bio))
bio_integrity_trim(clone, 0, len);
}
static struct dm_target_io *alloc_tio(struct clone_info *ci,
struct dm_target *ti,
unsigned target_bio_nr)
{
struct dm_target_io *tio;
struct bio *clone;
clone = bio_alloc_bioset(GFP_NOIO, 0, ci->md->bs);
tio = container_of(clone, struct dm_target_io, clone);
tio->io = ci->io;
tio->ti = ti;
tio->target_bio_nr = target_bio_nr;
return tio;
}
static void __clone_and_map_simple_bio(struct clone_info *ci,
struct dm_target *ti,
unsigned target_bio_nr, unsigned *len)
{
struct dm_target_io *tio = alloc_tio(ci, ti, target_bio_nr);
struct bio *clone = &tio->clone;
tio->len_ptr = len;
__bio_clone_fast(clone, ci->bio);
if (len)
bio_setup_sector(clone, ci->sector, *len);
__map_bio(tio);
}
static void __send_duplicate_bios(struct clone_info *ci, struct dm_target *ti,
unsigned num_bios, unsigned *len)
{
unsigned target_bio_nr;
for (target_bio_nr = 0; target_bio_nr < num_bios; target_bio_nr++)
__clone_and_map_simple_bio(ci, ti, target_bio_nr, len);
}
static int __send_empty_flush(struct clone_info *ci)
{
unsigned target_nr = 0;
struct dm_target *ti;
BUG_ON(bio_has_data(ci->bio));
while ((ti = dm_table_get_target(ci->map, target_nr++)))
__send_duplicate_bios(ci, ti, ti->num_flush_bios, NULL);
return 0;
}
static void __clone_and_map_data_bio(struct clone_info *ci, struct dm_target *ti,
sector_t sector, unsigned *len)
{
struct bio *bio = ci->bio;
struct dm_target_io *tio;
unsigned target_bio_nr;
unsigned num_target_bios = 1;
/*
* Does the target want to receive duplicate copies of the bio?
*/
if (bio_data_dir(bio) == WRITE && ti->num_write_bios)
num_target_bios = ti->num_write_bios(ti, bio);
for (target_bio_nr = 0; target_bio_nr < num_target_bios; target_bio_nr++) {
tio = alloc_tio(ci, ti, target_bio_nr);
tio->len_ptr = len;
clone_bio(tio, bio, sector, *len);
__map_bio(tio);
}
}
typedef unsigned (*get_num_bios_fn)(struct dm_target *ti);
static unsigned get_num_discard_bios(struct dm_target *ti)
{
return ti->num_discard_bios;
}
static unsigned get_num_write_same_bios(struct dm_target *ti)
{
return ti->num_write_same_bios;
}
typedef bool (*is_split_required_fn)(struct dm_target *ti);
static bool is_split_required_for_discard(struct dm_target *ti)
{
return ti->split_discard_bios;
}
static int __send_changing_extent_only(struct clone_info *ci,
get_num_bios_fn get_num_bios,
is_split_required_fn is_split_required)
{
struct dm_target *ti;
unsigned len;
unsigned num_bios;
do {
ti = dm_table_find_target(ci->map, ci->sector);
if (!dm_target_is_valid(ti))
return -EIO;
/*
* Even though the device advertised support for this type of
* request, that does not mean every target supports it, and
* reconfiguration might also have changed that since the
* check was performed.
*/
num_bios = get_num_bios ? get_num_bios(ti) : 0;
if (!num_bios)
return -EOPNOTSUPP;
if (is_split_required && !is_split_required(ti))
len = min((sector_t)ci->sector_count, max_io_len_target_boundary(ci->sector, ti));
else
len = min((sector_t)ci->sector_count, max_io_len(ci->sector, ti));
__send_duplicate_bios(ci, ti, num_bios, &len);
ci->sector += len;
} while (ci->sector_count -= len);
return 0;
}
static int __send_discard(struct clone_info *ci)
{
return __send_changing_extent_only(ci, get_num_discard_bios,
is_split_required_for_discard);
}
static int __send_write_same(struct clone_info *ci)
{
return __send_changing_extent_only(ci, get_num_write_same_bios, NULL);
}
/*
* Select the correct strategy for processing a non-flush bio.
*/
static int __split_and_process_non_flush(struct clone_info *ci)
{
struct bio *bio = ci->bio;
struct dm_target *ti;
unsigned len;
if (unlikely(bio->bi_rw & REQ_DISCARD))
return __send_discard(ci);
else if (unlikely(bio->bi_rw & REQ_WRITE_SAME))
return __send_write_same(ci);
ti = dm_table_find_target(ci->map, ci->sector);
if (!dm_target_is_valid(ti))
return -EIO;
len = min_t(sector_t, max_io_len(ci->sector, ti), ci->sector_count);
__clone_and_map_data_bio(ci, ti, ci->sector, &len);
ci->sector += len;
ci->sector_count -= len;
return 0;
}
/*
* Entry point to split a bio into clones and submit them to the targets.
*/
static void __split_and_process_bio(struct mapped_device *md,
struct dm_table *map, struct bio *bio)
{
struct clone_info ci;
int error = 0;
if (unlikely(!map)) {
bio_io_error(bio);
return;
}
ci.map = map;
ci.md = md;
ci.io = alloc_io(md);
ci.io->error = 0;
atomic_set(&ci.io->io_count, 1);
ci.io->bio = bio;
ci.io->md = md;
spin_lock_init(&ci.io->endio_lock);
ci.sector = bio->bi_iter.bi_sector;
start_io_acct(ci.io);
if (bio->bi_rw & REQ_FLUSH) {
ci.bio = &ci.md->flush_bio;
ci.sector_count = 0;
error = __send_empty_flush(&ci);
/* dec_pending submits any data associated with flush */
} else {
ci.bio = bio;
ci.sector_count = bio_sectors(bio);
while (ci.sector_count && !error)
error = __split_and_process_non_flush(&ci);
}
/* drop the extra reference count */
dec_pending(ci.io, error);
}
/*-----------------------------------------------------------------
* CRUD END
*---------------------------------------------------------------*/
/*
* The request function that just remaps the bio built up by
* dm_merge_bvec.
*/
static blk_qc_t dm_make_request(struct request_queue *q, struct bio *bio)
{
int rw = bio_data_dir(bio);
struct mapped_device *md = q->queuedata;
int srcu_idx;
struct dm_table *map;
map = dm_get_live_table(md, &srcu_idx);
generic_start_io_acct(rw, bio_sectors(bio), &dm_disk(md)->part0);
/* if we're suspended, we have to queue this io for later */
if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags))) {
dm_put_live_table(md, srcu_idx);
if (bio_rw(bio) != READA)
queue_io(md, bio);
else
bio_io_error(bio);
return BLK_QC_T_NONE;
}
__split_and_process_bio(md, map, bio);
dm_put_live_table(md, srcu_idx);
return BLK_QC_T_NONE;
}
int dm_request_based(struct mapped_device *md)
{
return blk_queue_stackable(md->queue);
}
static void dm_dispatch_clone_request(struct request *clone, struct request *rq)
{
int r;
if (blk_queue_io_stat(clone->q))
clone->cmd_flags |= REQ_IO_STAT;
clone->start_time = jiffies;
r = blk_insert_cloned_request(clone->q, clone);
if (r)
/* must complete clone in terms of original request */
dm_complete_request(rq, r);
}
static int dm_rq_bio_constructor(struct bio *bio, struct bio *bio_orig,
void *data)
{
struct dm_rq_target_io *tio = data;
struct dm_rq_clone_bio_info *info =
container_of(bio, struct dm_rq_clone_bio_info, clone);
info->orig = bio_orig;
info->tio = tio;
bio->bi_end_io = end_clone_bio;
return 0;
}
static int setup_clone(struct request *clone, struct request *rq,
struct dm_rq_target_io *tio, gfp_t gfp_mask)
{
int r;
r = blk_rq_prep_clone(clone, rq, tio->md->bs, gfp_mask,
dm_rq_bio_constructor, tio);
if (r)
return r;
clone->cmd = rq->cmd;
clone->cmd_len = rq->cmd_len;
clone->sense = rq->sense;
clone->end_io = end_clone_request;
clone->end_io_data = tio;
tio->clone = clone;
return 0;
}
static struct request *clone_rq(struct request *rq, struct mapped_device *md,
struct dm_rq_target_io *tio, gfp_t gfp_mask)
{
/*
* Do not allocate a clone if tio->clone was already set
* (see: dm_mq_queue_rq).
*/
bool alloc_clone = !tio->clone;
struct request *clone;
if (alloc_clone) {
clone = alloc_clone_request(md, gfp_mask);
if (!clone)
return NULL;
} else
clone = tio->clone;
blk_rq_init(NULL, clone);
if (setup_clone(clone, rq, tio, gfp_mask)) {
/* -ENOMEM */
if (alloc_clone)
free_clone_request(md, clone);
return NULL;
}
return clone;
}
static void map_tio_request(struct kthread_work *work);
static void init_tio(struct dm_rq_target_io *tio, struct request *rq,
struct mapped_device *md)
{
tio->md = md;
tio->ti = NULL;
tio->clone = NULL;
tio->orig = rq;
tio->error = 0;
memset(&tio->info, 0, sizeof(tio->info));
if (md->kworker_task)
init_kthread_work(&tio->work, map_tio_request);
}
static struct dm_rq_target_io *prep_tio(struct request *rq,
struct mapped_device *md, gfp_t gfp_mask)
{
struct dm_rq_target_io *tio;
int srcu_idx;
struct dm_table *table;
tio = alloc_rq_tio(md, gfp_mask);
if (!tio)
return NULL;
init_tio(tio, rq, md);
table = dm_get_live_table(md, &srcu_idx);
if (!dm_table_mq_request_based(table)) {
if (!clone_rq(rq, md, tio, gfp_mask)) {
dm_put_live_table(md, srcu_idx);
free_rq_tio(tio);
return NULL;
}
}
dm_put_live_table(md, srcu_idx);
return tio;
}
/*
* Called with the queue lock held.
*/
static int dm_prep_fn(struct request_queue *q, struct request *rq)
{
struct mapped_device *md = q->queuedata;
struct dm_rq_target_io *tio;
if (unlikely(rq->special)) {
DMWARN("Already has something in rq->special.");
return BLKPREP_KILL;
}
tio = prep_tio(rq, md, GFP_ATOMIC);
if (!tio)
return BLKPREP_DEFER;
rq->special = tio;
rq->cmd_flags |= REQ_DONTPREP;
return BLKPREP_OK;
}
/*
* Returns:
* 0 : the request has been processed
* DM_MAPIO_REQUEUE : the original request needs to be requeued
* < 0 : the request was completed due to failure
*/
static int map_request(struct dm_rq_target_io *tio, struct request *rq,
struct mapped_device *md)
{
int r;
struct dm_target *ti = tio->ti;
struct request *clone = NULL;
if (tio->clone) {
clone = tio->clone;
r = ti->type->map_rq(ti, clone, &tio->info);
} else {
r = ti->type->clone_and_map_rq(ti, rq, &tio->info, &clone);
if (r < 0) {
/* The target wants to complete the I/O */
dm_kill_unmapped_request(rq, r);
return r;
}
if (r != DM_MAPIO_REMAPPED)
return r;
if (setup_clone(clone, rq, tio, GFP_ATOMIC)) {
/* -ENOMEM */
ti->type->release_clone_rq(clone);
return DM_MAPIO_REQUEUE;
}
}
switch (r) {
case DM_MAPIO_SUBMITTED:
/* The target has taken the I/O to submit by itself later */
break;
case DM_MAPIO_REMAPPED:
/* The target has remapped the I/O so dispatch it */
trace_block_rq_remap(clone->q, clone, disk_devt(dm_disk(md)),
blk_rq_pos(rq));
dm_dispatch_clone_request(clone, rq);
break;
case DM_MAPIO_REQUEUE:
/* The target wants to requeue the I/O */
dm_requeue_original_request(md, tio->orig);
break;
default:
if (r > 0) {
DMWARN("unimplemented target map return value: %d", r);
BUG();
}
/* The target wants to complete the I/O */
dm_kill_unmapped_request(rq, r);
return r;
}
return 0;
}
static void map_tio_request(struct kthread_work *work)
{
struct dm_rq_target_io *tio = container_of(work, struct dm_rq_target_io, work);
struct request *rq = tio->orig;
struct mapped_device *md = tio->md;
if (map_request(tio, rq, md) == DM_MAPIO_REQUEUE)
dm_requeue_original_request(md, rq);
}
static void dm_start_request(struct mapped_device *md, struct request *orig)
{
if (!orig->q->mq_ops)
blk_start_request(orig);
else
blk_mq_start_request(orig);
atomic_inc(&md->pending[rq_data_dir(orig)]);
if (md->seq_rq_merge_deadline_usecs) {
md->last_rq_pos = rq_end_sector(orig);
md->last_rq_rw = rq_data_dir(orig);
md->last_rq_start_time = ktime_get();
}
if (unlikely(dm_stats_used(&md->stats))) {
struct dm_rq_target_io *tio = tio_from_request(orig);
tio->duration_jiffies = jiffies;
tio->n_sectors = blk_rq_sectors(orig);
dm_stats_account_io(&md->stats, orig->cmd_flags, blk_rq_pos(orig),
tio->n_sectors, false, 0, &tio->stats_aux);
}
/*
* Hold the md reference here for the in-flight I/O.
* We can't rely on the reference count by device opener,
* because the device may be closed during the request completion
* when all bios are completed.
* See the comment in rq_completed() too.
*/
dm_get(md);
}
#define MAX_SEQ_RQ_MERGE_DEADLINE_USECS 100000
ssize_t dm_attr_rq_based_seq_io_merge_deadline_show(struct mapped_device *md, char *buf)
{
return sprintf(buf, "%u\n", md->seq_rq_merge_deadline_usecs);
}
ssize_t dm_attr_rq_based_seq_io_merge_deadline_store(struct mapped_device *md,
const char *buf, size_t count)
{
unsigned deadline;
if (!dm_request_based(md) || md->use_blk_mq)
return count;
if (kstrtouint(buf, 10, &deadline))
return -EINVAL;
if (deadline > MAX_SEQ_RQ_MERGE_DEADLINE_USECS)
deadline = MAX_SEQ_RQ_MERGE_DEADLINE_USECS;
md->seq_rq_merge_deadline_usecs = deadline;
return count;
}
static bool dm_request_peeked_before_merge_deadline(struct mapped_device *md)
{
ktime_t kt_deadline;
if (!md->seq_rq_merge_deadline_usecs)
return false;
kt_deadline = ns_to_ktime((u64)md->seq_rq_merge_deadline_usecs * NSEC_PER_USEC);
kt_deadline = ktime_add_safe(md->last_rq_start_time, kt_deadline);
return !ktime_after(ktime_get(), kt_deadline);
}
/*
* q->request_fn for request-based dm.
* Called with the queue lock held.
*/
static void dm_request_fn(struct request_queue *q)
{
struct mapped_device *md = q->queuedata;
int srcu_idx;
struct dm_table *map = dm_get_live_table(md, &srcu_idx);
struct dm_target *ti;
struct request *rq;
struct dm_rq_target_io *tio;
sector_t pos;
/*
* For suspend, check blk_queue_stopped() and increment
* ->pending within a single queue_lock not to increment the
* number of in-flight I/Os after the queue is stopped in
* dm_suspend().
*/
while (!blk_queue_stopped(q)) {
rq = blk_peek_request(q);
if (!rq)
goto out;
/* always use block 0 to find the target for flushes for now */
pos = 0;
if (!(rq->cmd_flags & REQ_FLUSH))
pos = blk_rq_pos(rq);
ti = dm_table_find_target(map, pos);
if (!dm_target_is_valid(ti)) {
/*
* Must perform setup, that rq_completed() requires,
* before calling dm_kill_unmapped_request
*/
DMERR_LIMIT("request attempted access beyond the end of device");
dm_start_request(md, rq);
dm_kill_unmapped_request(rq, -EIO);
continue;
}
if (dm_request_peeked_before_merge_deadline(md) &&
md_in_flight(md) && rq->bio && rq->bio->bi_vcnt == 1 &&
md->last_rq_pos == pos && md->last_rq_rw == rq_data_dir(rq))
goto delay_and_out;
if (ti->type->busy && ti->type->busy(ti))
goto delay_and_out;
dm_start_request(md, rq);
tio = tio_from_request(rq);
/* Establish tio->ti before queuing work (map_tio_request) */
tio->ti = ti;
queue_kthread_work(&md->kworker, &tio->work);
BUG_ON(!irqs_disabled());
}
goto out;
delay_and_out:
blk_delay_queue(q, HZ / 100);
out:
dm_put_live_table(md, srcu_idx);
}
static int dm_any_congested(void *congested_data, int bdi_bits)
{
int r = bdi_bits;
struct mapped_device *md = congested_data;
struct dm_table *map;
if (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) {
map = dm_get_live_table_fast(md);
if (map) {
/*
* Request-based dm cares about only own queue for
* the query about congestion status of request_queue
*/
if (dm_request_based(md))
r = md->queue->backing_dev_info.wb.state &
bdi_bits;
else
r = dm_table_any_congested(map, bdi_bits);
}
dm_put_live_table_fast(md);
}
return r;
}
/*-----------------------------------------------------------------
* An IDR is used to keep track of allocated minor numbers.
*---------------------------------------------------------------*/
static void free_minor(int minor)
{
spin_lock(&_minor_lock);
idr_remove(&_minor_idr, minor);
spin_unlock(&_minor_lock);
}
/*
* See if the device with a specific minor # is free.
*/
static int specific_minor(int minor)
{
int r;
if (minor >= (1 << MINORBITS))
return -EINVAL;
idr_preload(GFP_KERNEL);
spin_lock(&_minor_lock);
r = idr_alloc(&_minor_idr, MINOR_ALLOCED, minor, minor + 1, GFP_NOWAIT);
spin_unlock(&_minor_lock);
idr_preload_end();
if (r < 0)
return r == -ENOSPC ? -EBUSY : r;
return 0;
}
static int next_free_minor(int *minor)
{
int r;
idr_preload(GFP_KERNEL);
spin_lock(&_minor_lock);
r = idr_alloc(&_minor_idr, MINOR_ALLOCED, 0, 1 << MINORBITS, GFP_NOWAIT);
spin_unlock(&_minor_lock);
idr_preload_end();
if (r < 0)
return r;
*minor = r;
return 0;
}
static const struct block_device_operations dm_blk_dops;
static void dm_wq_work(struct work_struct *work);
static void dm_init_md_queue(struct mapped_device *md)
{
/*
* Request-based dm devices cannot be stacked on top of bio-based dm
* devices. The type of this dm device may not have been decided yet.
* The type is decided at the first table loading time.
* To prevent problematic device stacking, clear the queue flag
* for request stacking support until then.
*
* This queue is new, so no concurrency on the queue_flags.
*/
queue_flag_clear_unlocked(QUEUE_FLAG_STACKABLE, md->queue);
/*
* Initialize data that will only be used by a non-blk-mq DM queue
* - must do so here (in alloc_dev callchain) before queue is used
*/
md->queue->queuedata = md;
md->queue->backing_dev_info.congested_data = md;
}
static void dm_init_old_md_queue(struct mapped_device *md)
{
md->use_blk_mq = false;
dm_init_md_queue(md);
/*
* Initialize aspects of queue that aren't relevant for blk-mq
*/
md->queue->backing_dev_info.congested_fn = dm_any_congested;
blk_queue_bounce_limit(md->queue, BLK_BOUNCE_ANY);
}
static void cleanup_mapped_device(struct mapped_device *md)
{
if (md->wq)
destroy_workqueue(md->wq);
if (md->kworker_task)
kthread_stop(md->kworker_task);
mempool_destroy(md->io_pool);
mempool_destroy(md->rq_pool);
if (md->bs)
bioset_free(md->bs);
cleanup_srcu_struct(&md->io_barrier);
if (md->disk) {
spin_lock(&_minor_lock);
md->disk->private_data = NULL;
spin_unlock(&_minor_lock);
del_gendisk(md->disk);
put_disk(md->disk);
}
if (md->queue)
blk_cleanup_queue(md->queue);
if (md->bdev) {
bdput(md->bdev);
md->bdev = NULL;
}
}
/*
* Allocate and initialise a blank device with a given minor.
*/
static struct mapped_device *alloc_dev(int minor)
{
int r;
struct mapped_device *md = kzalloc(sizeof(*md), GFP_KERNEL);
void *old_md;
if (!md) {
DMWARN("unable to allocate device, out of memory.");
return NULL;
}
if (!try_module_get(THIS_MODULE))
goto bad_module_get;
/* get a minor number for the dev */
if (minor == DM_ANY_MINOR)
r = next_free_minor(&minor);
else
r = specific_minor(minor);
if (r < 0)
goto bad_minor;
r = init_srcu_struct(&md->io_barrier);
if (r < 0)
goto bad_io_barrier;
md->use_blk_mq = use_blk_mq;
md->type = DM_TYPE_NONE;
mutex_init(&md->suspend_lock);
mutex_init(&md->type_lock);
mutex_init(&md->table_devices_lock);
spin_lock_init(&md->deferred_lock);
atomic_set(&md->holders, 1);
atomic_set(&md->open_count, 0);
atomic_set(&md->event_nr, 0);
atomic_set(&md->uevent_seq, 0);
INIT_LIST_HEAD(&md->uevent_list);
INIT_LIST_HEAD(&md->table_devices);
spin_lock_init(&md->uevent_lock);
md->queue = blk_alloc_queue(GFP_KERNEL);
if (!md->queue)
goto bad;
dm_init_md_queue(md);
md->disk = alloc_disk(1);
if (!md->disk)
goto bad;
atomic_set(&md->pending[0], 0);
atomic_set(&md->pending[1], 0);
init_waitqueue_head(&md->wait);
INIT_WORK(&md->work, dm_wq_work);
init_waitqueue_head(&md->eventq);
init_completion(&md->kobj_holder.completion);
md->kworker_task = NULL;
md->disk->major = _major;
md->disk->first_minor = minor;
md->disk->fops = &dm_blk_dops;
md->disk->queue = md->queue;
md->disk->private_data = md;
sprintf(md->disk->disk_name, "dm-%d", minor);
add_disk(md->disk);
format_dev_t(md->name, MKDEV(_major, minor));
md->wq = alloc_workqueue("kdmflush", WQ_MEM_RECLAIM, 0);
if (!md->wq)
goto bad;
md->bdev = bdget_disk(md->disk, 0);
if (!md->bdev)
goto bad;
bio_init(&md->flush_bio);
md->flush_bio.bi_bdev = md->bdev;
md->flush_bio.bi_rw = WRITE_FLUSH;
dm_stats_init(&md->stats);
/* Populate the mapping, nobody knows we exist yet */
spin_lock(&_minor_lock);
old_md = idr_replace(&_minor_idr, md, minor);
spin_unlock(&_minor_lock);
BUG_ON(old_md != MINOR_ALLOCED);
return md;
bad:
cleanup_mapped_device(md);
bad_io_barrier:
free_minor(minor);
bad_minor:
module_put(THIS_MODULE);
bad_module_get:
kfree(md);
return NULL;
}
static void unlock_fs(struct mapped_device *md);
static void free_dev(struct mapped_device *md)
{
int minor = MINOR(disk_devt(md->disk));
unlock_fs(md);
cleanup_mapped_device(md);
if (md->use_blk_mq)
blk_mq_free_tag_set(&md->tag_set);
free_table_devices(&md->table_devices);
dm_stats_cleanup(&md->stats);
free_minor(minor);
module_put(THIS_MODULE);
kfree(md);
}
static void __bind_mempools(struct mapped_device *md, struct dm_table *t)
{
struct dm_md_mempools *p = dm_table_get_md_mempools(t);
if (md->bs) {
/* The md already has necessary mempools. */
if (dm_table_get_type(t) == DM_TYPE_BIO_BASED) {
/*
* Reload bioset because front_pad may have changed
* because a different table was loaded.
*/
bioset_free(md->bs);
md->bs = p->bs;
p->bs = NULL;
}
/*
* There's no need to reload with request-based dm
* because the size of front_pad doesn't change.
* Note for future: If you are to reload bioset,
* prep-ed requests in the queue may refer
* to bio from the old bioset, so you must walk
* through the queue to unprep.
*/
goto out;
}
BUG_ON(!p || md->io_pool || md->rq_pool || md->bs);
md->io_pool = p->io_pool;
p->io_pool = NULL;
md->rq_pool = p->rq_pool;
p->rq_pool = NULL;
md->bs = p->bs;
p->bs = NULL;
out:
/* mempool bind completed, no longer need any mempools in the table */
dm_table_free_md_mempools(t);
}
/*
* Bind a table to the device.
*/
static void event_callback(void *context)
{
unsigned long flags;
LIST_HEAD(uevents);
struct mapped_device *md = (struct mapped_device *) context;
spin_lock_irqsave(&md->uevent_lock, flags);
list_splice_init(&md->uevent_list, &uevents);
spin_unlock_irqrestore(&md->uevent_lock, flags);
dm_send_uevents(&uevents, &disk_to_dev(md->disk)->kobj);
atomic_inc(&md->event_nr);
wake_up(&md->eventq);
}
/*
* Protected by md->suspend_lock obtained by dm_swap_table().
*/
static void __set_size(struct mapped_device *md, sector_t size)
{
set_capacity(md->disk, size);
i_size_write(md->bdev->bd_inode, (loff_t)size << SECTOR_SHIFT);
}
/*
* Returns old map, which caller must destroy.
*/
static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t,
struct queue_limits *limits)
{
struct dm_table *old_map;
struct request_queue *q = md->queue;
sector_t size;
size = dm_table_get_size(t);
/*
* Wipe any geometry if the size of the table changed.
*/
if (size != dm_get_size(md))
memset(&md->geometry, 0, sizeof(md->geometry));
__set_size(md, size);
dm_table_event_callback(t, event_callback, md);
/*
* The queue hasn't been stopped yet, if the old table type wasn't
* for request-based during suspension. So stop it to prevent
* I/O mapping before resume.
* This must be done before setting the queue restrictions,
* because request-based dm may be run just after the setting.
*/
if (dm_table_request_based(t))
stop_queue(q);
__bind_mempools(md, t);
old_map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock));
rcu_assign_pointer(md->map, t);
md->immutable_target_type = dm_table_get_immutable_target_type(t);
dm_table_set_restrictions(t, q, limits);
if (old_map)
dm_sync_table(md);
return old_map;
}
/*
* Returns unbound table for the caller to free.
*/
static struct dm_table *__unbind(struct mapped_device *md)
{
struct dm_table *map = rcu_dereference_protected(md->map, 1);
if (!map)
return NULL;
dm_table_event_callback(map, NULL, NULL);
RCU_INIT_POINTER(md->map, NULL);
dm_sync_table(md);
return map;
}
/*
* Constructor for a new device.
*/
int dm_create(int minor, struct mapped_device **result)
{
struct mapped_device *md;
md = alloc_dev(minor);
if (!md)
return -ENXIO;
dm_sysfs_init(md);
*result = md;
return 0;
}
/*
* Functions to manage md->type.
* All are required to hold md->type_lock.
*/
void dm_lock_md_type(struct mapped_device *md)
{
mutex_lock(&md->type_lock);
}
void dm_unlock_md_type(struct mapped_device *md)
{
mutex_unlock(&md->type_lock);
}
void dm_set_md_type(struct mapped_device *md, unsigned type)
{
BUG_ON(!mutex_is_locked(&md->type_lock));
md->type = type;
}
unsigned dm_get_md_type(struct mapped_device *md)
{
BUG_ON(!mutex_is_locked(&md->type_lock));
return md->type;
}
struct target_type *dm_get_immutable_target_type(struct mapped_device *md)
{
return md->immutable_target_type;
}
/*
* The queue_limits are only valid as long as you have a reference
* count on 'md'.
*/
struct queue_limits *dm_get_queue_limits(struct mapped_device *md)
{
BUG_ON(!atomic_read(&md->holders));
return &md->queue->limits;
}
EXPORT_SYMBOL_GPL(dm_get_queue_limits);
static void init_rq_based_worker_thread(struct mapped_device *md)
{
/* Initialize the request-based DM worker thread */
init_kthread_worker(&md->kworker);
md->kworker_task = kthread_run(kthread_worker_fn, &md->kworker,
"kdmwork-%s", dm_device_name(md));
}
/*
* Fully initialize a request-based queue (->elevator, ->request_fn, etc).
*/
static int dm_init_request_based_queue(struct mapped_device *md)
{
struct request_queue *q = NULL;
/* Fully initialize the queue */
q = blk_init_allocated_queue(md->queue, dm_request_fn, NULL);
if (!q)
return -EINVAL;
/* disable dm_request_fn's merge heuristic by default */
md->seq_rq_merge_deadline_usecs = 0;
md->queue = q;
dm_init_old_md_queue(md);
blk_queue_softirq_done(md->queue, dm_softirq_done);
blk_queue_prep_rq(md->queue, dm_prep_fn);
init_rq_based_worker_thread(md);
elv_register_queue(md->queue);
return 0;
}
static int dm_mq_init_request(void *data, struct request *rq,
unsigned int hctx_idx, unsigned int request_idx,
unsigned int numa_node)
{
struct mapped_device *md = data;
struct dm_rq_target_io *tio = blk_mq_rq_to_pdu(rq);
/*
* Must initialize md member of tio, otherwise it won't
* be available in dm_mq_queue_rq.
*/
tio->md = md;
return 0;
}
static int dm_mq_queue_rq(struct blk_mq_hw_ctx *hctx,
const struct blk_mq_queue_data *bd)
{
struct request *rq = bd->rq;
struct dm_rq_target_io *tio = blk_mq_rq_to_pdu(rq);
struct mapped_device *md = tio->md;
int srcu_idx;
struct dm_table *map = dm_get_live_table(md, &srcu_idx);
struct dm_target *ti;
sector_t pos;
/* always use block 0 to find the target for flushes for now */
pos = 0;
if (!(rq->cmd_flags & REQ_FLUSH))
pos = blk_rq_pos(rq);
ti = dm_table_find_target(map, pos);
if (!dm_target_is_valid(ti)) {
dm_put_live_table(md, srcu_idx);
DMERR_LIMIT("request attempted access beyond the end of device");
/*
* Must perform setup, that rq_completed() requires,
* before returning BLK_MQ_RQ_QUEUE_ERROR
*/
dm_start_request(md, rq);
return BLK_MQ_RQ_QUEUE_ERROR;
}
dm_put_live_table(md, srcu_idx);
if (ti->type->busy && ti->type->busy(ti))
return BLK_MQ_RQ_QUEUE_BUSY;
dm_start_request(md, rq);
/* Init tio using md established in .init_request */
init_tio(tio, rq, md);
/*
* Establish tio->ti before queuing work (map_tio_request)
* or making direct call to map_request().
*/
tio->ti = ti;
/* Clone the request if underlying devices aren't blk-mq */
if (dm_table_get_type(map) == DM_TYPE_REQUEST_BASED) {
/* clone request is allocated at the end of the pdu */
tio->clone = (void *)blk_mq_rq_to_pdu(rq) + sizeof(struct dm_rq_target_io);
(void) clone_rq(rq, md, tio, GFP_ATOMIC);
queue_kthread_work(&md->kworker, &tio->work);
} else {
/* Direct call is fine since .queue_rq allows allocations */
if (map_request(tio, rq, md) == DM_MAPIO_REQUEUE) {
/* Undo dm_start_request() before requeuing */
rq_end_stats(md, rq);
rq_completed(md, rq_data_dir(rq), false);
return BLK_MQ_RQ_QUEUE_BUSY;
}
}
return BLK_MQ_RQ_QUEUE_OK;
}
static struct blk_mq_ops dm_mq_ops = {
.queue_rq = dm_mq_queue_rq,
.map_queue = blk_mq_map_queue,
.complete = dm_softirq_done,
.init_request = dm_mq_init_request,
};
static int dm_init_request_based_blk_mq_queue(struct mapped_device *md)
{
unsigned md_type = dm_get_md_type(md);
struct request_queue *q;
int err;
memset(&md->tag_set, 0, sizeof(md->tag_set));
md->tag_set.ops = &dm_mq_ops;
md->tag_set.queue_depth = BLKDEV_MAX_RQ;
md->tag_set.numa_node = NUMA_NO_NODE;
md->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE;
md->tag_set.nr_hw_queues = 1;
if (md_type == DM_TYPE_REQUEST_BASED) {
/* make the memory for non-blk-mq clone part of the pdu */
md->tag_set.cmd_size = sizeof(struct dm_rq_target_io) + sizeof(struct request);
} else
md->tag_set.cmd_size = sizeof(struct dm_rq_target_io);
md->tag_set.driver_data = md;
err = blk_mq_alloc_tag_set(&md->tag_set);
if (err)
return err;
q = blk_mq_init_allocated_queue(&md->tag_set, md->queue);
if (IS_ERR(q)) {
err = PTR_ERR(q);
goto out_tag_set;
}
md->queue = q;
dm_init_md_queue(md);
/* backfill 'mq' sysfs registration normally done in blk_register_queue */
blk_mq_register_disk(md->disk);
if (md_type == DM_TYPE_REQUEST_BASED)
init_rq_based_worker_thread(md);
return 0;
out_tag_set:
blk_mq_free_tag_set(&md->tag_set);
return err;
}
static unsigned filter_md_type(unsigned type, struct mapped_device *md)
{
if (type == DM_TYPE_BIO_BASED)
return type;
return !md->use_blk_mq ? DM_TYPE_REQUEST_BASED : DM_TYPE_MQ_REQUEST_BASED;
}
/*
* Setup the DM device's queue based on md's type
*/
int dm_setup_md_queue(struct mapped_device *md)
{
int r;
unsigned md_type = filter_md_type(dm_get_md_type(md), md);
switch (md_type) {
case DM_TYPE_REQUEST_BASED:
r = dm_init_request_based_queue(md);
if (r) {
DMWARN("Cannot initialize queue for request-based mapped device");
return r;
}
break;
case DM_TYPE_MQ_REQUEST_BASED:
r = dm_init_request_based_blk_mq_queue(md);
if (r) {
DMWARN("Cannot initialize queue for request-based blk-mq mapped device");
return r;
}
break;
case DM_TYPE_BIO_BASED:
dm_init_old_md_queue(md);
blk_queue_make_request(md->queue, dm_make_request);
/*
* DM handles splitting bios as needed. Free the bio_split bioset
* since it won't be used (saves 1 process per bio-based DM device).
*/
bioset_free(md->queue->bio_split);
md->queue->bio_split = NULL;
break;
}
return 0;
}
struct mapped_device *dm_get_md(dev_t dev)
{
struct mapped_device *md;
unsigned minor = MINOR(dev);
if (MAJOR(dev) != _major || minor >= (1 << MINORBITS))
return NULL;
spin_lock(&_minor_lock);
md = idr_find(&_minor_idr, minor);
if (md) {
if ((md == MINOR_ALLOCED ||
(MINOR(disk_devt(dm_disk(md))) != minor) ||
dm_deleting_md(md) ||
test_bit(DMF_FREEING, &md->flags))) {
md = NULL;
goto out;
}
dm_get(md);
}
out:
spin_unlock(&_minor_lock);
return md;
}
EXPORT_SYMBOL_GPL(dm_get_md);
void *dm_get_mdptr(struct mapped_device *md)
{
return md->interface_ptr;
}
void dm_set_mdptr(struct mapped_device *md, void *ptr)
{
md->interface_ptr = ptr;
}
void dm_get(struct mapped_device *md)
{
atomic_inc(&md->holders);
BUG_ON(test_bit(DMF_FREEING, &md->flags));
}
int dm_hold(struct mapped_device *md)
{
spin_lock(&_minor_lock);
if (test_bit(DMF_FREEING, &md->flags)) {
spin_unlock(&_minor_lock);
return -EBUSY;
}
dm_get(md);
spin_unlock(&_minor_lock);
return 0;
}
EXPORT_SYMBOL_GPL(dm_hold);
const char *dm_device_name(struct mapped_device *md)
{
return md->name;
}
EXPORT_SYMBOL_GPL(dm_device_name);
static void __dm_destroy(struct mapped_device *md, bool wait)
{
struct dm_table *map;
int srcu_idx;
might_sleep();
spin_lock(&_minor_lock);
idr_replace(&_minor_idr, MINOR_ALLOCED, MINOR(disk_devt(dm_disk(md))));
set_bit(DMF_FREEING, &md->flags);
spin_unlock(&_minor_lock);
if (dm_request_based(md) && md->kworker_task)
flush_kthread_worker(&md->kworker);
/*
* Take suspend_lock so that presuspend and postsuspend methods
* do not race with internal suspend.
*/
mutex_lock(&md->suspend_lock);
map = dm_get_live_table(md, &srcu_idx);
if (!dm_suspended_md(md)) {
dm_table_presuspend_targets(map);
dm_table_postsuspend_targets(map);
}
/* dm_put_live_table must be before msleep, otherwise deadlock is possible */
dm_put_live_table(md, srcu_idx);
mutex_unlock(&md->suspend_lock);
/*
* Rare, but there may be I/O requests still going to complete,
* for example. Wait for all references to disappear.
* No one should increment the reference count of the mapped_device,
* after the mapped_device state becomes DMF_FREEING.
*/
if (wait)
while (atomic_read(&md->holders))
msleep(1);
else if (atomic_read(&md->holders))
DMWARN("%s: Forcibly removing mapped_device still in use! (%d users)",
dm_device_name(md), atomic_read(&md->holders));
dm_sysfs_exit(md);
dm_table_destroy(__unbind(md));
free_dev(md);
}
void dm_destroy(struct mapped_device *md)
{
__dm_destroy(md, true);
}
void dm_destroy_immediate(struct mapped_device *md)
{
__dm_destroy(md, false);
}
void dm_put(struct mapped_device *md)
{
atomic_dec(&md->holders);
}
EXPORT_SYMBOL_GPL(dm_put);
static int dm_wait_for_completion(struct mapped_device *md, int interruptible)
{
int r = 0;
DECLARE_WAITQUEUE(wait, current);
add_wait_queue(&md->wait, &wait);
while (1) {
set_current_state(interruptible);
if (!md_in_flight(md))
break;
if (interruptible == TASK_INTERRUPTIBLE &&
signal_pending(current)) {
r = -EINTR;
break;
}
io_schedule();
}
set_current_state(TASK_RUNNING);
remove_wait_queue(&md->wait, &wait);
return r;
}
/*
* Process the deferred bios
*/
static void dm_wq_work(struct work_struct *work)
{
struct mapped_device *md = container_of(work, struct mapped_device,
work);
struct bio *c;
int srcu_idx;
struct dm_table *map;
map = dm_get_live_table(md, &srcu_idx);
while (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) {
spin_lock_irq(&md->deferred_lock);
c = bio_list_pop(&md->deferred);
spin_unlock_irq(&md->deferred_lock);
if (!c)
break;
if (dm_request_based(md))
generic_make_request(c);
else
__split_and_process_bio(md, map, c);
}
dm_put_live_table(md, srcu_idx);
}
static void dm_queue_flush(struct mapped_device *md)
{
clear_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
smp_mb__after_atomic();
queue_work(md->wq, &md->work);
}
/*
* Swap in a new table, returning the old one for the caller to destroy.
*/
struct dm_table *dm_swap_table(struct mapped_device *md, struct dm_table *table)
{
struct dm_table *live_map = NULL, *map = ERR_PTR(-EINVAL);
struct queue_limits limits;
int r;
mutex_lock(&md->suspend_lock);
/* device must be suspended */
if (!dm_suspended_md(md))
goto out;
/*
* If the new table has no data devices, retain the existing limits.
* This helps multipath with queue_if_no_path if all paths disappear,
* then new I/O is queued based on these limits, and then some paths
* reappear.
*/
if (dm_table_has_no_data_devices(table)) {
live_map = dm_get_live_table_fast(md);
if (live_map)
limits = md->queue->limits;
dm_put_live_table_fast(md);
}
if (!live_map) {
r = dm_calculate_queue_limits(table, &limits);
if (r) {
map = ERR_PTR(r);
goto out;
}
}
map = __bind(md, table, &limits);
out:
mutex_unlock(&md->suspend_lock);
return map;
}
/*
* Functions to lock and unlock any filesystem running on the
* device.
*/
static int lock_fs(struct mapped_device *md)
{
int r;
WARN_ON(md->frozen_sb);
md->frozen_sb = freeze_bdev(md->bdev);
if (IS_ERR(md->frozen_sb)) {
r = PTR_ERR(md->frozen_sb);
md->frozen_sb = NULL;
return r;
}
set_bit(DMF_FROZEN, &md->flags);
return 0;
}
static void unlock_fs(struct mapped_device *md)
{
if (!test_bit(DMF_FROZEN, &md->flags))
return;
thaw_bdev(md->bdev, md->frozen_sb);
md->frozen_sb = NULL;
clear_bit(DMF_FROZEN, &md->flags);
}
/*
* If __dm_suspend returns 0, the device is completely quiescent
* now. There is no request-processing activity. All new requests
* are being added to md->deferred list.
*
* Caller must hold md->suspend_lock
*/
static int __dm_suspend(struct mapped_device *md, struct dm_table *map,
unsigned suspend_flags, int interruptible)
{
bool do_lockfs = suspend_flags & DM_SUSPEND_LOCKFS_FLAG;
bool noflush = suspend_flags & DM_SUSPEND_NOFLUSH_FLAG;
int r;
/*
* DMF_NOFLUSH_SUSPENDING must be set before presuspend.
* This flag is cleared before dm_suspend returns.
*/
if (noflush)
set_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
/*
* This gets reverted if there's an error later and the targets
* provide the .presuspend_undo hook.
*/
dm_table_presuspend_targets(map);
/*
* Flush I/O to the device.
* Any I/O submitted after lock_fs() may not be flushed.
* noflush takes precedence over do_lockfs.
* (lock_fs() flushes I/Os and waits for them to complete.)
*/
if (!noflush && do_lockfs) {
r = lock_fs(md);
if (r) {
dm_table_presuspend_undo_targets(map);
return r;
}
}
/*
* Here we must make sure that no processes are submitting requests
* to target drivers i.e. no one may be executing
* __split_and_process_bio. This is called from dm_request and
* dm_wq_work.
*
* To get all processes out of __split_and_process_bio in dm_request,
* we take the write lock. To prevent any process from reentering
* __split_and_process_bio from dm_request and quiesce the thread
* (dm_wq_work), we set BMF_BLOCK_IO_FOR_SUSPEND and call
* flush_workqueue(md->wq).
*/
set_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
if (map)
synchronize_srcu(&md->io_barrier);
/*
* Stop md->queue before flushing md->wq in case request-based
* dm defers requests to md->wq from md->queue.
*/
if (dm_request_based(md)) {
stop_queue(md->queue);
if (md->kworker_task)
flush_kthread_worker(&md->kworker);
}
flush_workqueue(md->wq);
/*
* At this point no more requests are entering target request routines.
* We call dm_wait_for_completion to wait for all existing requests
* to finish.
*/
r = dm_wait_for_completion(md, interruptible);
if (noflush)
clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
if (map)
synchronize_srcu(&md->io_barrier);
/* were we interrupted ? */
if (r < 0) {
dm_queue_flush(md);
if (dm_request_based(md))
start_queue(md->queue);
unlock_fs(md);
dm_table_presuspend_undo_targets(map);
/* pushback list is already flushed, so skip flush */
}
return r;
}
/*
* We need to be able to change a mapping table under a mounted
* filesystem. For example we might want to move some data in
* the background. Before the table can be swapped with
* dm_bind_table, dm_suspend must be called to flush any in
* flight bios and ensure that any further io gets deferred.
*/
/*
* Suspend mechanism in request-based dm.
*
* 1. Flush all I/Os by lock_fs() if needed.
* 2. Stop dispatching any I/O by stopping the request_queue.
* 3. Wait for all in-flight I/Os to be completed or requeued.
*
* To abort suspend, start the request_queue.
*/
int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
{
struct dm_table *map = NULL;
int r = 0;
retry:
mutex_lock_nested(&md->suspend_lock, SINGLE_DEPTH_NESTING);
if (dm_suspended_md(md)) {
r = -EINVAL;
goto out_unlock;
}
if (dm_suspended_internally_md(md)) {
/* already internally suspended, wait for internal resume */
mutex_unlock(&md->suspend_lock);
r = wait_on_bit(&md->flags, DMF_SUSPENDED_INTERNALLY, TASK_INTERRUPTIBLE);
if (r)
return r;
goto retry;
}
map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock));
r = __dm_suspend(md, map, suspend_flags, TASK_INTERRUPTIBLE);
if (r)
goto out_unlock;
set_bit(DMF_SUSPENDED, &md->flags);
dm_table_postsuspend_targets(map);
out_unlock:
mutex_unlock(&md->suspend_lock);
return r;
}
static int __dm_resume(struct mapped_device *md, struct dm_table *map)
{
if (map) {
int r = dm_table_resume_targets(map);
if (r)
return r;
}
dm_queue_flush(md);
/*
* Flushing deferred I/Os must be done after targets are resumed
* so that mapping of targets can work correctly.
* Request-based dm is queueing the deferred I/Os in its request_queue.
*/
if (dm_request_based(md))
start_queue(md->queue);
unlock_fs(md);
return 0;
}
int dm_resume(struct mapped_device *md)
{
int r = -EINVAL;
struct dm_table *map = NULL;
retry:
mutex_lock_nested(&md->suspend_lock, SINGLE_DEPTH_NESTING);
if (!dm_suspended_md(md))
goto out;
if (dm_suspended_internally_md(md)) {
/* already internally suspended, wait for internal resume */
mutex_unlock(&md->suspend_lock);
r = wait_on_bit(&md->flags, DMF_SUSPENDED_INTERNALLY, TASK_INTERRUPTIBLE);
if (r)
return r;
goto retry;
}
map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock));
if (!map || !dm_table_get_size(map))
goto out;
r = __dm_resume(md, map);
if (r)
goto out;
clear_bit(DMF_SUSPENDED, &md->flags);
r = 0;
out:
mutex_unlock(&md->suspend_lock);
return r;
}
/*
* Internal suspend/resume works like userspace-driven suspend. It waits
* until all bios finish and prevents issuing new bios to the target drivers.
* It may be used only from the kernel.
*/
static void __dm_internal_suspend(struct mapped_device *md, unsigned suspend_flags)
{
struct dm_table *map = NULL;
if (md->internal_suspend_count++)
return; /* nested internal suspend */
if (dm_suspended_md(md)) {
set_bit(DMF_SUSPENDED_INTERNALLY, &md->flags);
return; /* nest suspend */
}
map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock));
/*
* Using TASK_UNINTERRUPTIBLE because only NOFLUSH internal suspend is
* supported. Properly supporting a TASK_INTERRUPTIBLE internal suspend
* would require changing .presuspend to return an error -- avoid this
* until there is a need for more elaborate variants of internal suspend.
*/
(void) __dm_suspend(md, map, suspend_flags, TASK_UNINTERRUPTIBLE);
set_bit(DMF_SUSPENDED_INTERNALLY, &md->flags);
dm_table_postsuspend_targets(map);
}
static void __dm_internal_resume(struct mapped_device *md)
{
BUG_ON(!md->internal_suspend_count);
if (--md->internal_suspend_count)
return; /* resume from nested internal suspend */
if (dm_suspended_md(md))
goto done; /* resume from nested suspend */
/*
* NOTE: existing callers don't need to call dm_table_resume_targets
* (which may fail -- so best to avoid it for now by passing NULL map)
*/
(void) __dm_resume(md, NULL);
done:
clear_bit(DMF_SUSPENDED_INTERNALLY, &md->flags);
smp_mb__after_atomic();
wake_up_bit(&md->flags, DMF_SUSPENDED_INTERNALLY);
}
void dm_internal_suspend_noflush(struct mapped_device *md)
{
mutex_lock(&md->suspend_lock);
__dm_internal_suspend(md, DM_SUSPEND_NOFLUSH_FLAG);
mutex_unlock(&md->suspend_lock);
}
EXPORT_SYMBOL_GPL(dm_internal_suspend_noflush);
void dm_internal_resume(struct mapped_device *md)
{
mutex_lock(&md->suspend_lock);
__dm_internal_resume(md);
mutex_unlock(&md->suspend_lock);
}
EXPORT_SYMBOL_GPL(dm_internal_resume);
/*
* Fast variants of internal suspend/resume hold md->suspend_lock,
* which prevents interaction with userspace-driven suspend.
*/
void dm_internal_suspend_fast(struct mapped_device *md)
{
mutex_lock(&md->suspend_lock);
if (dm_suspended_md(md) || dm_suspended_internally_md(md))
return;
set_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
synchronize_srcu(&md->io_barrier);
flush_workqueue(md->wq);
dm_wait_for_completion(md, TASK_UNINTERRUPTIBLE);
}
EXPORT_SYMBOL_GPL(dm_internal_suspend_fast);
void dm_internal_resume_fast(struct mapped_device *md)
{
if (dm_suspended_md(md) || dm_suspended_internally_md(md))
goto done;
dm_queue_flush(md);
done:
mutex_unlock(&md->suspend_lock);
}
EXPORT_SYMBOL_GPL(dm_internal_resume_fast);
/*-----------------------------------------------------------------
* Event notification.
*---------------------------------------------------------------*/
int dm_kobject_uevent(struct mapped_device *md, enum kobject_action action,
unsigned cookie)
{
char udev_cookie[DM_COOKIE_LENGTH];
char *envp[] = { udev_cookie, NULL };
if (!cookie)
return kobject_uevent(&disk_to_dev(md->disk)->kobj, action);
else {
snprintf(udev_cookie, DM_COOKIE_LENGTH, "%s=%u",
DM_COOKIE_ENV_VAR_NAME, cookie);
return kobject_uevent_env(&disk_to_dev(md->disk)->kobj,
action, envp);
}
}
uint32_t dm_next_uevent_seq(struct mapped_device *md)
{
return atomic_add_return(1, &md->uevent_seq);
}
uint32_t dm_get_event_nr(struct mapped_device *md)
{
return atomic_read(&md->event_nr);
}
int dm_wait_event(struct mapped_device *md, int event_nr)
{
return wait_event_interruptible(md->eventq,
(event_nr != atomic_read(&md->event_nr)));
}
void dm_uevent_add(struct mapped_device *md, struct list_head *elist)
{
unsigned long flags;
spin_lock_irqsave(&md->uevent_lock, flags);
list_add(elist, &md->uevent_list);
spin_unlock_irqrestore(&md->uevent_lock, flags);
}
/*
* The gendisk is only valid as long as you have a reference
* count on 'md'.
*/
struct gendisk *dm_disk(struct mapped_device *md)
{
return md->disk;
}
EXPORT_SYMBOL_GPL(dm_disk);
struct kobject *dm_kobject(struct mapped_device *md)
{
return &md->kobj_holder.kobj;
}
struct mapped_device *dm_get_from_kobject(struct kobject *kobj)
{
struct mapped_device *md;
md = container_of(kobj, struct mapped_device, kobj_holder.kobj);
if (test_bit(DMF_FREEING, &md->flags) ||
dm_deleting_md(md))
return NULL;
dm_get(md);
return md;
}
int dm_suspended_md(struct mapped_device *md)
{
return test_bit(DMF_SUSPENDED, &md->flags);
}
int dm_suspended_internally_md(struct mapped_device *md)
{
return test_bit(DMF_SUSPENDED_INTERNALLY, &md->flags);
}
int dm_test_deferred_remove_flag(struct mapped_device *md)
{
return test_bit(DMF_DEFERRED_REMOVE, &md->flags);
}
int dm_suspended(struct dm_target *ti)
{
return dm_suspended_md(dm_table_get_md(ti->table));
}
EXPORT_SYMBOL_GPL(dm_suspended);
int dm_noflush_suspending(struct dm_target *ti)
{
return __noflush_suspending(dm_table_get_md(ti->table));
}
EXPORT_SYMBOL_GPL(dm_noflush_suspending);
struct dm_md_mempools *dm_alloc_md_mempools(struct mapped_device *md, unsigned type,
unsigned integrity, unsigned per_bio_data_size)
{
struct dm_md_mempools *pools = kzalloc(sizeof(*pools), GFP_KERNEL);
struct kmem_cache *cachep = NULL;
unsigned int pool_size = 0;
unsigned int front_pad;
if (!pools)
return NULL;
type = filter_md_type(type, md);
switch (type) {
case DM_TYPE_BIO_BASED:
cachep = _io_cache;
pool_size = dm_get_reserved_bio_based_ios();
front_pad = roundup(per_bio_data_size, __alignof__(struct dm_target_io)) + offsetof(struct dm_target_io, clone);
break;
case DM_TYPE_REQUEST_BASED:
cachep = _rq_tio_cache;
pool_size = dm_get_reserved_rq_based_ios();
pools->rq_pool = mempool_create_slab_pool(pool_size, _rq_cache);
if (!pools->rq_pool)
goto out;
/* fall through to setup remaining rq-based pools */
case DM_TYPE_MQ_REQUEST_BASED:
if (!pool_size)
pool_size = dm_get_reserved_rq_based_ios();
front_pad = offsetof(struct dm_rq_clone_bio_info, clone);
/* per_bio_data_size is not used. See __bind_mempools(). */
WARN_ON(per_bio_data_size != 0);
break;
default:
BUG();
}
if (cachep) {
pools->io_pool = mempool_create_slab_pool(pool_size, cachep);
if (!pools->io_pool)
goto out;
}
pools->bs = bioset_create_nobvec(pool_size, front_pad);
if (!pools->bs)
goto out;
if (integrity && bioset_integrity_create(pools->bs, pool_size))
goto out;
return pools;
out:
dm_free_md_mempools(pools);
return NULL;
}
void dm_free_md_mempools(struct dm_md_mempools *pools)
{
if (!pools)
return;
mempool_destroy(pools->io_pool);
mempool_destroy(pools->rq_pool);
if (pools->bs)
bioset_free(pools->bs);
kfree(pools);
}
static int dm_pr_register(struct block_device *bdev, u64 old_key, u64 new_key,
u32 flags)
{
struct mapped_device *md = bdev->bd_disk->private_data;
const struct pr_ops *ops;
struct dm_target *tgt;
fmode_t mode;
int srcu_idx, r;
r = dm_get_live_table_for_ioctl(md, &tgt, &bdev, &mode, &srcu_idx);
if (r < 0)
return r;
ops = bdev->bd_disk->fops->pr_ops;
if (ops && ops->pr_register)
r = ops->pr_register(bdev, old_key, new_key, flags);
else
r = -EOPNOTSUPP;
dm_put_live_table(md, srcu_idx);
return r;
}
static int dm_pr_reserve(struct block_device *bdev, u64 key, enum pr_type type,
u32 flags)
{
struct mapped_device *md = bdev->bd_disk->private_data;
const struct pr_ops *ops;
struct dm_target *tgt;
fmode_t mode;
int srcu_idx, r;
r = dm_get_live_table_for_ioctl(md, &tgt, &bdev, &mode, &srcu_idx);
if (r < 0)
return r;
ops = bdev->bd_disk->fops->pr_ops;
if (ops && ops->pr_reserve)
r = ops->pr_reserve(bdev, key, type, flags);
else
r = -EOPNOTSUPP;
dm_put_live_table(md, srcu_idx);
return r;
}
static int dm_pr_release(struct block_device *bdev, u64 key, enum pr_type type)
{
struct mapped_device *md = bdev->bd_disk->private_data;
const struct pr_ops *ops;
struct dm_target *tgt;
fmode_t mode;
int srcu_idx, r;
r = dm_get_live_table_for_ioctl(md, &tgt, &bdev, &mode, &srcu_idx);
if (r < 0)
return r;
ops = bdev->bd_disk->fops->pr_ops;
if (ops && ops->pr_release)
r = ops->pr_release(bdev, key, type);
else
r = -EOPNOTSUPP;
dm_put_live_table(md, srcu_idx);
return r;
}
static int dm_pr_preempt(struct block_device *bdev, u64 old_key, u64 new_key,
enum pr_type type, bool abort)
{
struct mapped_device *md = bdev->bd_disk->private_data;
const struct pr_ops *ops;
struct dm_target *tgt;
fmode_t mode;
int srcu_idx, r;
r = dm_get_live_table_for_ioctl(md, &tgt, &bdev, &mode, &srcu_idx);
if (r < 0)
return r;
ops = bdev->bd_disk->fops->pr_ops;
if (ops && ops->pr_preempt)
r = ops->pr_preempt(bdev, old_key, new_key, type, abort);
else
r = -EOPNOTSUPP;
dm_put_live_table(md, srcu_idx);
return r;
}
static int dm_pr_clear(struct block_device *bdev, u64 key)
{
struct mapped_device *md = bdev->bd_disk->private_data;
const struct pr_ops *ops;
struct dm_target *tgt;
fmode_t mode;
int srcu_idx, r;
r = dm_get_live_table_for_ioctl(md, &tgt, &bdev, &mode, &srcu_idx);
if (r < 0)
return r;
ops = bdev->bd_disk->fops->pr_ops;
if (ops && ops->pr_clear)
r = ops->pr_clear(bdev, key);
else
r = -EOPNOTSUPP;
dm_put_live_table(md, srcu_idx);
return r;
}
static const struct pr_ops dm_pr_ops = {
.pr_register = dm_pr_register,
.pr_reserve = dm_pr_reserve,
.pr_release = dm_pr_release,
.pr_preempt = dm_pr_preempt,
.pr_clear = dm_pr_clear,
};
static const struct block_device_operations dm_blk_dops = {
.open = dm_blk_open,
.release = dm_blk_close,
.ioctl = dm_blk_ioctl,
.getgeo = dm_blk_getgeo,
.pr_ops = &dm_pr_ops,
.owner = THIS_MODULE
};
/*
* module hooks
*/
module_init(dm_init);
module_exit(dm_exit);
module_param(major, uint, 0);
MODULE_PARM_DESC(major, "The major number of the device mapper");
module_param(reserved_bio_based_ios, uint, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(reserved_bio_based_ios, "Reserved IOs in bio-based mempools");
module_param(reserved_rq_based_ios, uint, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(reserved_rq_based_ios, "Reserved IOs in request-based mempools");
module_param(use_blk_mq, bool, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(use_blk_mq, "Use block multiqueue for request-based DM devices");
MODULE_DESCRIPTION(DM_NAME " driver");
MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
MODULE_LICENSE("GPL");