| /* |
| * 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; |
| 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_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); |
| } |
| |
| 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) { |
| 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_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); |
| } |
| |
| 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); |
| } |
| |
| 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); |
| 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); |
| |
| if (md->disk) { |
| 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); |
| } |
| |
| 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); |
| } |
| |
| /* |
| * 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_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); |
| 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"); |