diff options
Diffstat (limited to 'drivers/md/dm.c')
| -rw-r--r-- | drivers/md/dm.c | 3650 |
1 files changed, 3650 insertions, 0 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c new file mode 100644 index 000000000..2caf49289 --- /dev/null +++ b/drivers/md/dm.c @@ -0,0 +1,3650 @@ +/* + * 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 <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; +}; + +/* + * 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_MERGE_IS_OPTIONAL 6 +#define DMF_DEFERRED_REMOVE 7 +#define DMF_SUSPENDED_INTERNALLY 8 + +/* + * 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_blk_ioctl(struct block_device *bdev, fmode_t mode, + unsigned int cmd, unsigned long arg) +{ + struct mapped_device *md = bdev->bd_disk->private_data; + int srcu_idx; + struct dm_table *map; + struct dm_target *tgt; + int r = -ENOTTY; + +retry: + 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->ioctl) + goto out; + + if (dm_suspended_md(md)) { + r = -EAGAIN; + goto out; + } + + r = tgt->type->ioctl(tgt, cmd, arg); + +out: + dm_put_live_table(md, srcu_idx); + + if (r == -ENOTCONN) { + msleep(10); + goto retry; + } + + 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_endio(bio, io_error); + } + } +} + +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) +{ + 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 (!bio_flagged(bio, BIO_UPTODATE) && !error) + error = -EIO; + + 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, int error) +{ + 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; + + 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); +} + +/* + * 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) +{ + int nr_requests_pending; + + atomic_dec(&md->pending[rw]); + + /* nudge anyone waiting on suspend queue */ + nr_requests_pending = md_in_flight(md); + if (!nr_requests_pending) + 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 if (!nr_requests_pending || + (nr_requests_pending >= md->queue->nr_congestion_on)) + 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); + 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_unmapped_original_request(struct mapped_device *md, + struct request *rq) +{ + int rw = rq_data_dir(rq); + + dm_unprep_request(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 dm_requeue_unmapped_request(struct request *clone) +{ + struct dm_rq_target_io *tio = clone->end_io_data; + + dm_requeue_unmapped_original_request(tio->md, tio->orig); +} + +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_unmapped_request(clone); + 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) { + 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) { + 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 + *---------------------------------------------------------------*/ + +static int dm_merge_bvec(struct request_queue *q, + struct bvec_merge_data *bvm, + struct bio_vec *biovec) +{ + struct mapped_device *md = q->queuedata; + struct dm_table *map = dm_get_live_table_fast(md); + struct dm_target *ti; + sector_t max_sectors, max_size = 0; + + if (unlikely(!map)) + goto out; + + ti = dm_table_find_target(map, bvm->bi_sector); + if (!dm_target_is_valid(ti)) + goto out; + + /* + * Find maximum amount of I/O that won't need splitting + */ + max_sectors = min(max_io_len(bvm->bi_sector, ti), + (sector_t) queue_max_sectors(q)); + max_size = (max_sectors << SECTOR_SHIFT) - bvm->bi_size; + + /* + * FIXME: this stop-gap fix _must_ be cleaned up (by passing a sector_t + * to the targets' merge function since it holds sectors not bytes). + * Just doing this as an interim fix for stable@ because the more + * comprehensive cleanup of switching to sector_t will impact every + * DM target that implements a ->merge hook. + */ + if (max_size > INT_MAX) + max_size = INT_MAX; + + /* + * merge_bvec_fn() returns number of bytes + * it can accept at this offset + * max is precomputed maximal io size + */ + if (max_size && ti->type->merge) + max_size = ti->type->merge(ti, bvm, biovec, (int) max_size); + /* + * If the target doesn't support merge method and some of the devices + * provided their merge_bvec method (we know this by looking for the + * max_hw_sectors that dm_set_device_limits may set), then we can't + * allow bios with multiple vector entries. So always set max_size + * to 0, and the code below allows just one page. + */ + else if (queue_max_hw_sectors(q) <= PAGE_SIZE >> 9) + max_size = 0; + +out: + dm_put_live_table_fast(md); + /* + * Always allow an entire first page + */ + if (max_size <= biovec->bv_len && !(bvm->bi_size >> SECTOR_SHIFT)) + max_size = biovec->bv_len; + + return max_size; +} + +/* + * The request function that just remaps the bio built up by + * dm_merge_bvec. + */ +static void 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; + } + + __split_and_process_bio(md, map, bio); + dm_put_live_table(md, srcu_idx); + return; +} + +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_unmapped_request(clone); + 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_unmapped_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(); + } + + /* + * 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.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); +} + +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->queuedata = md; + md->queue->backing_dev_info.congested_fn = dm_any_congested; + md->queue->backing_dev_info.congested_data = md; + + blk_queue_bounce_limit(md->queue, BLK_BOUNCE_ANY); +} + +/* + * 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_queue; + + dm_init_md_queue(md); + + md->disk = alloc_disk(1); + if (!md->disk) + goto bad_disk; + + 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_thread; + + md->bdev = bdget_disk(md->disk, 0); + if (!md->bdev) + goto bad_bdev; + + 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_bdev: + destroy_workqueue(md->wq); +bad_thread: + del_gendisk(md->disk); + put_disk(md->disk); +bad_disk: + blk_cleanup_queue(md->queue); +bad_queue: + cleanup_srcu_struct(&md->io_barrier); +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); + destroy_workqueue(md->wq); + + if (md->kworker_task) + kthread_stop(md->kworker_task); + if (md->io_pool) + mempool_destroy(md->io_pool); + if (md->rq_pool) + mempool_destroy(md->rq_pool); + if (md->bs) + bioset_free(md->bs); + + cleanup_srcu_struct(&md->io_barrier); + free_table_devices(&md->table_devices); + dm_stats_cleanup(&md->stats); + + spin_lock(&_minor_lock); + md->disk->private_data = NULL; + spin_unlock(&_minor_lock); + if (blk_get_integrity(md->disk)) + blk_integrity_unregister(md->disk); + del_gendisk(md->disk); + put_disk(md->disk); + blk_cleanup_queue(md->queue); + if (md->use_blk_mq) + blk_mq_free_tag_set(&md->tag_set); + bdput(md->bdev); + 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); +} + +/* + * Return 1 if the queue has a compulsory merge_bvec_fn function. + * + * If this function returns 0, then the device is either a non-dm + * device without a merge_bvec_fn, or it is a dm device that is + * able to split any bios it receives that are too big. + */ +int dm_queue_merge_is_compulsory(struct request_queue *q) +{ + struct mapped_device *dev_md; + + if (!q->merge_bvec_fn) + return 0; + + if (q->make_request_fn == dm_make_request) { + dev_md = q->queuedata; + if (test_bit(DMF_MERGE_IS_OPTIONAL, &dev_md->flags)) + return 0; + } + + return 1; +} + +static int dm_device_merge_is_compulsory(struct dm_target *ti, + struct dm_dev *dev, sector_t start, + sector_t len, void *data) +{ + struct block_device *bdev = dev->bdev; + struct request_queue *q = bdev_get_queue(bdev); + + return dm_queue_merge_is_compulsory(q); +} + +/* + * Return 1 if it is acceptable to ignore merge_bvec_fn based + * on the properties of the underlying devices. + */ +static int dm_table_merge_is_optional(struct dm_table *table) +{ + unsigned i = 0; + struct dm_target *ti; + + while (i < dm_table_get_num_targets(table)) { + ti = dm_table_get_target(table, i++); + + if (ti->type->iterate_devices && + ti->type->iterate_devices(ti, dm_device_merge_is_compulsory, NULL)) + return 0; + } + + return 1; +} + +/* + * 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; + int merge_is_optional; + + 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); + + merge_is_optional = dm_table_merge_is_optional(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 (merge_is_optional) + set_bit(DMF_MERGE_IS_OPTIONAL, &md->flags); + else + clear_bit(DMF_MERGE_IS_OPTIONAL, &md->flags); + 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_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); + blk_queue_merge_bvec(md->queue, dm_merge_bvec); + 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(); + + map = dm_get_live_table(md, &srcu_idx); + + 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); + if (!dm_suspended_md(md)) { + dm_table_presuspend_targets(map); + dm_table_postsuspend_targets(map); + } + mutex_unlock(&md->suspend_lock); + + /* dm_put_live_table must be before msleep, otherwise deadlock is possible */ + dm_put_live_table(md, srcu_idx); + + /* + * 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; + + if (pools->io_pool) + mempool_destroy(pools->io_pool); + + if (pools->rq_pool) + mempool_destroy(pools->rq_pool); + + if (pools->bs) + bioset_free(pools->bs); + + kfree(pools); +} + +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, + .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"); |