--- /dev/null
+/*
+ * Copyright (C) 2001, 2002 Sistina Software (UK) Limited.
+ * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
+ *
+ * This file is released under the GPL.
+ */
+
+#include "dm.h"
+#include "dm-uevent.h"
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/moduleparam.h>
+#include <linux/blkpg.h>
+#include <linux/bio.h>
+#include <linux/mempool.h>
+#include <linux/slab.h>
+#include <linux/idr.h>
+#include <linux/hdreg.h>
+#include <linux/delay.h>
+#include <linux/wait.h>
+#include <linux/kthread.h>
+#include <linux/ktime.h>
+#include <linux/elevator.h> /* for rq_end_sector() */
+#include <linux/blk-mq.h>
+
+#include <trace/events/block.h>
+
+#define DM_MSG_PREFIX "core"
+
+#ifdef CONFIG_PRINTK
+/*
+ * ratelimit state to be used in DMXXX_LIMIT().
+ */
+DEFINE_RATELIMIT_STATE(dm_ratelimit_state,
+ DEFAULT_RATELIMIT_INTERVAL,
+ DEFAULT_RATELIMIT_BURST);
+EXPORT_SYMBOL(dm_ratelimit_state);
+#endif
+
+/*
+ * Cookies are numeric values sent with CHANGE and REMOVE
+ * uevents while resuming, removing or renaming the device.
+ */
+#define DM_COOKIE_ENV_VAR_NAME "DM_COOKIE"
+#define DM_COOKIE_LENGTH 24
+
+static const char *_name = DM_NAME;
+
+static unsigned int major = 0;
+static unsigned int _major = 0;
+
+static DEFINE_IDR(_minor_idr);
+
+static DEFINE_SPINLOCK(_minor_lock);
+
+static void do_deferred_remove(struct work_struct *w);
+
+static DECLARE_WORK(deferred_remove_work, do_deferred_remove);
+
+static struct workqueue_struct *deferred_remove_workqueue;
+
+/*
+ * For bio-based dm.
+ * One of these is allocated per bio.
+ */
+struct dm_io {
+ struct mapped_device *md;
+ int error;
+ atomic_t io_count;
+ struct bio *bio;
+ unsigned long start_time;
+ spinlock_t endio_lock;
+ struct dm_stats_aux stats_aux;
+};
+
+/*
+ * For request-based dm.
+ * One of these is allocated per request.
+ */
+struct dm_rq_target_io {
+ struct mapped_device *md;
+ struct dm_target *ti;
+ struct request *orig, *clone;
+ struct kthread_work work;
+ int error;
+ union map_info info;
+};
+
+/*
+ * For request-based dm - the bio clones we allocate are embedded in these
+ * structs.
+ *
+ * We allocate these with bio_alloc_bioset, using the front_pad parameter when
+ * the bioset is created - this means the bio has to come at the end of the
+ * struct.
+ */
+struct dm_rq_clone_bio_info {
+ struct bio *orig;
+ struct dm_rq_target_io *tio;
+ struct bio clone;
+};
+
+union map_info *dm_get_rq_mapinfo(struct request *rq)
+{
+ if (rq && rq->end_io_data)
+ return &((struct dm_rq_target_io *)rq->end_io_data)->info;
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(dm_get_rq_mapinfo);
+
+#define MINOR_ALLOCED ((void *)-1)
+
+/*
+ * Bits for the md->flags field.
+ */
+#define DMF_BLOCK_IO_FOR_SUSPEND 0
+#define DMF_SUSPENDED 1
+#define DMF_FROZEN 2
+#define DMF_FREEING 3
+#define DMF_DELETING 4
+#define DMF_NOFLUSH_SUSPENDING 5
+#define DMF_MERGE_IS_OPTIONAL 6
+#define DMF_DEFERRED_REMOVE 7
+#define DMF_SUSPENDED_INTERNALLY 8
+
+/*
+ * A dummy definition to make RCU happy.
+ * struct dm_table should never be dereferenced in this file.
+ */
+struct dm_table {
+ int undefined__;
+};
+
+/*
+ * Work processed by per-device workqueue.
+ */
+struct mapped_device {
+ struct srcu_struct io_barrier;
+ struct mutex suspend_lock;
+ atomic_t holders;
+ atomic_t open_count;
+
+ /*
+ * The current mapping.
+ * Use dm_get_live_table{_fast} or take suspend_lock for
+ * dereference.
+ */
+ struct dm_table __rcu *map;
+
+ struct list_head table_devices;
+ struct mutex table_devices_lock;
+
+ unsigned long flags;
+
+ struct request_queue *queue;
+ unsigned type;
+ /* Protect queue and type against concurrent access. */
+ struct mutex type_lock;
+
+ struct target_type *immutable_target_type;
+
+ struct gendisk *disk;
+ char name[16];
+
+ void *interface_ptr;
+
+ /*
+ * A list of ios that arrived while we were suspended.
+ */
+ atomic_t pending[2];
+ wait_queue_head_t wait;
+ struct work_struct work;
+ struct bio_list deferred;
+ spinlock_t deferred_lock;
+
+ /*
+ * Processing queue (flush)
+ */
+ struct workqueue_struct *wq;
+
+ /*
+ * io objects are allocated from here.
+ */
+ mempool_t *io_pool;
+ mempool_t *rq_pool;
+
+ struct bio_set *bs;
+
+ /*
+ * Event handling.
+ */
+ atomic_t event_nr;
+ wait_queue_head_t eventq;
+ atomic_t uevent_seq;
+ struct list_head uevent_list;
+ spinlock_t uevent_lock; /* Protect access to uevent_list */
+
+ /*
+ * freeze/thaw support require holding onto a super block
+ */
+ struct super_block *frozen_sb;
+ struct block_device *bdev;
+
+ /* forced geometry settings */
+ struct hd_geometry geometry;
+
+ /* kobject and completion */
+ struct dm_kobject_holder kobj_holder;
+
+ /* zero-length flush that will be cloned and submitted to targets */
+ struct bio flush_bio;
+
+ /* the number of internal suspends */
+ unsigned internal_suspend_count;
+
+ struct dm_stats stats;
+
+ struct kthread_worker kworker;
+ struct task_struct *kworker_task;
+
+ /* for request-based merge heuristic in dm_request_fn() */
+ unsigned seq_rq_merge_deadline_usecs;
+ int last_rq_rw;
+ sector_t last_rq_pos;
+ ktime_t last_rq_start_time;
+
+ /* for blk-mq request-based DM support */
+ struct blk_mq_tag_set tag_set;
+ bool use_blk_mq;
+};
+
+#ifdef CONFIG_DM_MQ_DEFAULT
+static bool use_blk_mq = true;
+#else
+static bool use_blk_mq = false;
+#endif
+
+bool dm_use_blk_mq(struct mapped_device *md)
+{
+ return md->use_blk_mq;
+}
+
+/*
+ * For mempools pre-allocation at the table loading time.
+ */
+struct dm_md_mempools {
+ mempool_t *io_pool;
+ mempool_t *rq_pool;
+ struct bio_set *bs;
+};
+
+struct table_device {
+ struct list_head list;
+ atomic_t count;
+ struct dm_dev dm_dev;
+};
+
+#define RESERVED_BIO_BASED_IOS 16
+#define RESERVED_REQUEST_BASED_IOS 256
+#define RESERVED_MAX_IOS 1024
+static struct kmem_cache *_io_cache;
+static struct kmem_cache *_rq_tio_cache;
+static struct kmem_cache *_rq_cache;
+
+/*
+ * Bio-based DM's mempools' reserved IOs set by the user.
+ */
+static unsigned reserved_bio_based_ios = RESERVED_BIO_BASED_IOS;
+
+/*
+ * Request-based DM's mempools' reserved IOs set by the user.
+ */
+static unsigned reserved_rq_based_ios = RESERVED_REQUEST_BASED_IOS;
+
+static unsigned __dm_get_module_param(unsigned *module_param,
+ unsigned def, unsigned max)
+{
+ unsigned param = ACCESS_ONCE(*module_param);
+ unsigned modified_param = 0;
+
+ if (!param)
+ modified_param = def;
+ else if (param > max)
+ modified_param = max;
+
+ if (modified_param) {
+ (void)cmpxchg(module_param, param, modified_param);
+ param = modified_param;
+ }
+
+ return param;
+}
+
+unsigned dm_get_reserved_bio_based_ios(void)
+{
+ return __dm_get_module_param(&reserved_bio_based_ios,
+ RESERVED_BIO_BASED_IOS, RESERVED_MAX_IOS);
+}
+EXPORT_SYMBOL_GPL(dm_get_reserved_bio_based_ios);
+
+unsigned dm_get_reserved_rq_based_ios(void)
+{
+ return __dm_get_module_param(&reserved_rq_based_ios,
+ RESERVED_REQUEST_BASED_IOS, RESERVED_MAX_IOS);
+}
+EXPORT_SYMBOL_GPL(dm_get_reserved_rq_based_ios);
+
+static int __init local_init(void)
+{
+ int r = -ENOMEM;
+
+ /* allocate a slab for the dm_ios */
+ _io_cache = KMEM_CACHE(dm_io, 0);
+ if (!_io_cache)
+ return r;
+
+ _rq_tio_cache = KMEM_CACHE(dm_rq_target_io, 0);
+ if (!_rq_tio_cache)
+ goto out_free_io_cache;
+
+ _rq_cache = kmem_cache_create("dm_clone_request", sizeof(struct request),
+ __alignof__(struct request), 0, NULL);
+ if (!_rq_cache)
+ goto out_free_rq_tio_cache;
+
+ r = dm_uevent_init();
+ if (r)
+ goto out_free_rq_cache;
+
+ deferred_remove_workqueue = alloc_workqueue("kdmremove", WQ_UNBOUND, 1);
+ if (!deferred_remove_workqueue) {
+ r = -ENOMEM;
+ goto out_uevent_exit;
+ }
+
+ _major = major;
+ r = register_blkdev(_major, _name);
+ if (r < 0)
+ goto out_free_workqueue;
+
+ if (!_major)
+ _major = r;
+
+ return 0;
+
+out_free_workqueue:
+ destroy_workqueue(deferred_remove_workqueue);
+out_uevent_exit:
+ dm_uevent_exit();
+out_free_rq_cache:
+ kmem_cache_destroy(_rq_cache);
+out_free_rq_tio_cache:
+ kmem_cache_destroy(_rq_tio_cache);
+out_free_io_cache:
+ kmem_cache_destroy(_io_cache);
+
+ return r;
+}
+
+static void local_exit(void)
+{
+ flush_scheduled_work();
+ destroy_workqueue(deferred_remove_workqueue);
+
+ kmem_cache_destroy(_rq_cache);
+ kmem_cache_destroy(_rq_tio_cache);
+ kmem_cache_destroy(_io_cache);
+ unregister_blkdev(_major, _name);
+ dm_uevent_exit();
+
+ _major = 0;
+
+ DMINFO("cleaned up");
+}
+
+static int (*_inits[])(void) __initdata = {
+ local_init,
+ dm_target_init,
+ dm_linear_init,
+ dm_stripe_init,
+ dm_io_init,
+ dm_kcopyd_init,
+ dm_interface_init,
+ dm_statistics_init,
+};
+
+static void (*_exits[])(void) = {
+ local_exit,
+ dm_target_exit,
+ dm_linear_exit,
+ dm_stripe_exit,
+ dm_io_exit,
+ dm_kcopyd_exit,
+ dm_interface_exit,
+ dm_statistics_exit,
+};
+
+static int __init dm_init(void)
+{
+ const int count = ARRAY_SIZE(_inits);
+
+ int r, i;
+
+ for (i = 0; i < count; i++) {
+ r = _inits[i]();
+ if (r)
+ goto bad;
+ }
+
+ return 0;
+
+ bad:
+ while (i--)
+ _exits[i]();
+
+ return r;
+}
+
+static void __exit dm_exit(void)
+{
+ int i = ARRAY_SIZE(_exits);
+
+ while (i--)
+ _exits[i]();
+
+ /*
+ * Should be empty by this point.
+ */
+ idr_destroy(&_minor_idr);
+}
+
+/*
+ * Block device functions
+ */
+int dm_deleting_md(struct mapped_device *md)
+{
+ return test_bit(DMF_DELETING, &md->flags);
+}
+
+static int dm_blk_open(struct block_device *bdev, fmode_t mode)
+{
+ struct mapped_device *md;
+
+ spin_lock(&_minor_lock);
+
+ md = bdev->bd_disk->private_data;
+ if (!md)
+ goto out;
+
+ if (test_bit(DMF_FREEING, &md->flags) ||
+ dm_deleting_md(md)) {
+ md = NULL;
+ goto out;
+ }
+
+ dm_get(md);
+ atomic_inc(&md->open_count);
+out:
+ spin_unlock(&_minor_lock);
+
+ return md ? 0 : -ENXIO;
+}
+
+static void dm_blk_close(struct gendisk *disk, fmode_t mode)
+{
+ struct mapped_device *md;
+
+ spin_lock(&_minor_lock);
+
+ md = disk->private_data;
+ if (WARN_ON(!md))
+ goto out;
+
+ if (atomic_dec_and_test(&md->open_count) &&
+ (test_bit(DMF_DEFERRED_REMOVE, &md->flags)))
+ queue_work(deferred_remove_workqueue, &deferred_remove_work);
+
+ dm_put(md);
+out:
+ spin_unlock(&_minor_lock);
+}
+
+int dm_open_count(struct mapped_device *md)
+{
+ return atomic_read(&md->open_count);
+}
+
+/*
+ * Guarantees nothing is using the device before it's deleted.
+ */
+int dm_lock_for_deletion(struct mapped_device *md, bool mark_deferred, bool only_deferred)
+{
+ int r = 0;
+
+ spin_lock(&_minor_lock);
+
+ if (dm_open_count(md)) {
+ r = -EBUSY;
+ if (mark_deferred)
+ set_bit(DMF_DEFERRED_REMOVE, &md->flags);
+ } else if (only_deferred && !test_bit(DMF_DEFERRED_REMOVE, &md->flags))
+ r = -EEXIST;
+ else
+ set_bit(DMF_DELETING, &md->flags);
+
+ spin_unlock(&_minor_lock);
+
+ return r;
+}
+
+int dm_cancel_deferred_remove(struct mapped_device *md)
+{
+ int r = 0;
+
+ spin_lock(&_minor_lock);
+
+ if (test_bit(DMF_DELETING, &md->flags))
+ r = -EBUSY;
+ else
+ clear_bit(DMF_DEFERRED_REMOVE, &md->flags);
+
+ spin_unlock(&_minor_lock);
+
+ return r;
+}
+
+static void do_deferred_remove(struct work_struct *w)
+{
+ dm_deferred_remove();
+}
+
+sector_t dm_get_size(struct mapped_device *md)
+{
+ return get_capacity(md->disk);
+}
+
+struct request_queue *dm_get_md_queue(struct mapped_device *md)
+{
+ return md->queue;
+}
+
+struct dm_stats *dm_get_stats(struct mapped_device *md)
+{
+ return &md->stats;
+}
+
+static int dm_blk_getgeo(struct block_device *bdev, struct hd_geometry *geo)
+{
+ struct mapped_device *md = bdev->bd_disk->private_data;
+
+ return dm_get_geometry(md, geo);
+}
+
+static int dm_blk_ioctl(struct block_device *bdev, fmode_t mode,
+ unsigned int cmd, unsigned long arg)
+{
+ struct mapped_device *md = bdev->bd_disk->private_data;
+ int srcu_idx;
+ struct dm_table *map;
+ struct dm_target *tgt;
+ int r = -ENOTTY;
+
+retry:
+ map = dm_get_live_table(md, &srcu_idx);
+
+ if (!map || !dm_table_get_size(map))
+ goto out;
+
+ /* We only support devices that have a single target */
+ if (dm_table_get_num_targets(map) != 1)
+ goto out;
+
+ tgt = dm_table_get_target(map, 0);
+ if (!tgt->type->ioctl)
+ goto out;
+
+ if (dm_suspended_md(md)) {
+ r = -EAGAIN;
+ goto out;
+ }
+
+ r = tgt->type->ioctl(tgt, cmd, arg);
+
+out:
+ dm_put_live_table(md, srcu_idx);
+
+ if (r == -ENOTCONN) {
+ msleep(10);
+ goto retry;
+ }
+
+ return r;
+}
+
+static struct dm_io *alloc_io(struct mapped_device *md)
+{
+ return mempool_alloc(md->io_pool, GFP_NOIO);
+}
+
+static void free_io(struct mapped_device *md, struct dm_io *io)
+{
+ mempool_free(io, md->io_pool);
+}
+
+static void free_tio(struct mapped_device *md, struct dm_target_io *tio)
+{
+ bio_put(&tio->clone);
+}
+
+static struct dm_rq_target_io *alloc_rq_tio(struct mapped_device *md,
+ gfp_t gfp_mask)
+{
+ return mempool_alloc(md->io_pool, gfp_mask);
+}
+
+static void free_rq_tio(struct dm_rq_target_io *tio)
+{
+ mempool_free(tio, tio->md->io_pool);
+}
+
+static struct request *alloc_clone_request(struct mapped_device *md,
+ gfp_t gfp_mask)
+{
+ return mempool_alloc(md->rq_pool, gfp_mask);
+}
+
+static void free_clone_request(struct mapped_device *md, struct request *rq)
+{
+ mempool_free(rq, md->rq_pool);
+}
+
+static int md_in_flight(struct mapped_device *md)
+{
+ return atomic_read(&md->pending[READ]) +
+ atomic_read(&md->pending[WRITE]);
+}
+
+static void start_io_acct(struct dm_io *io)
+{
+ struct mapped_device *md = io->md;
+ struct bio *bio = io->bio;
+ int cpu;
+ int rw = bio_data_dir(bio);
+
+ io->start_time = jiffies;
+
+ cpu = part_stat_lock();
+ part_round_stats(cpu, &dm_disk(md)->part0);
+ part_stat_unlock();
+ atomic_set(&dm_disk(md)->part0.in_flight[rw],
+ atomic_inc_return(&md->pending[rw]));
+
+ if (unlikely(dm_stats_used(&md->stats)))
+ dm_stats_account_io(&md->stats, bio->bi_rw, bio->bi_iter.bi_sector,
+ bio_sectors(bio), false, 0, &io->stats_aux);
+}
+
+static void end_io_acct(struct dm_io *io)
+{
+ struct mapped_device *md = io->md;
+ struct bio *bio = io->bio;
+ unsigned long duration = jiffies - io->start_time;
+ int pending;
+ int rw = bio_data_dir(bio);
+
+ generic_end_io_acct(rw, &dm_disk(md)->part0, io->start_time);
+
+ if (unlikely(dm_stats_used(&md->stats)))
+ dm_stats_account_io(&md->stats, bio->bi_rw, bio->bi_iter.bi_sector,
+ bio_sectors(bio), true, duration, &io->stats_aux);
+
+ /*
+ * After this is decremented the bio must not be touched if it is
+ * a flush.
+ */
+ pending = atomic_dec_return(&md->pending[rw]);
+ atomic_set(&dm_disk(md)->part0.in_flight[rw], pending);
+ pending += atomic_read(&md->pending[rw^0x1]);
+
+ /* nudge anyone waiting on suspend queue */
+ if (!pending)
+ wake_up(&md->wait);
+}
+
+/*
+ * Add the bio to the list of deferred io.
+ */
+static void queue_io(struct mapped_device *md, struct bio *bio)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&md->deferred_lock, flags);
+ bio_list_add(&md->deferred, bio);
+ spin_unlock_irqrestore(&md->deferred_lock, flags);
+ queue_work(md->wq, &md->work);
+}
+
+/*
+ * Everyone (including functions in this file), should use this
+ * function to access the md->map field, and make sure they call
+ * dm_put_live_table() when finished.
+ */
+struct dm_table *dm_get_live_table(struct mapped_device *md, int *srcu_idx) __acquires(md->io_barrier)
+{
+ *srcu_idx = srcu_read_lock(&md->io_barrier);
+
+ return srcu_dereference(md->map, &md->io_barrier);
+}
+
+void dm_put_live_table(struct mapped_device *md, int srcu_idx) __releases(md->io_barrier)
+{
+ srcu_read_unlock(&md->io_barrier, srcu_idx);
+}
+
+void dm_sync_table(struct mapped_device *md)
+{
+ synchronize_srcu(&md->io_barrier);
+ synchronize_rcu_expedited();
+}
+
+/*
+ * A fast alternative to dm_get_live_table/dm_put_live_table.
+ * The caller must not block between these two functions.
+ */
+static struct dm_table *dm_get_live_table_fast(struct mapped_device *md) __acquires(RCU)
+{
+ rcu_read_lock();
+ return rcu_dereference(md->map);
+}
+
+static void dm_put_live_table_fast(struct mapped_device *md) __releases(RCU)
+{
+ rcu_read_unlock();
+}
+
+/*
+ * Open a table device so we can use it as a map destination.
+ */
+static int open_table_device(struct table_device *td, dev_t dev,
+ struct mapped_device *md)
+{
+ static char *_claim_ptr = "I belong to device-mapper";
+ struct block_device *bdev;
+
+ int r;
+
+ BUG_ON(td->dm_dev.bdev);
+
+ bdev = blkdev_get_by_dev(dev, td->dm_dev.mode | FMODE_EXCL, _claim_ptr);
+ if (IS_ERR(bdev))
+ return PTR_ERR(bdev);
+
+ r = bd_link_disk_holder(bdev, dm_disk(md));
+ if (r) {
+ blkdev_put(bdev, td->dm_dev.mode | FMODE_EXCL);
+ return r;
+ }
+
+ td->dm_dev.bdev = bdev;
+ return 0;
+}
+
+/*
+ * Close a table device that we've been using.
+ */
+static void close_table_device(struct table_device *td, struct mapped_device *md)
+{
+ if (!td->dm_dev.bdev)
+ return;
+
+ bd_unlink_disk_holder(td->dm_dev.bdev, dm_disk(md));
+ blkdev_put(td->dm_dev.bdev, td->dm_dev.mode | FMODE_EXCL);
+ td->dm_dev.bdev = NULL;
+}
+
+static struct table_device *find_table_device(struct list_head *l, dev_t dev,
+ fmode_t mode) {
+ struct table_device *td;
+
+ list_for_each_entry(td, l, list)
+ if (td->dm_dev.bdev->bd_dev == dev && td->dm_dev.mode == mode)
+ return td;
+
+ return NULL;
+}
+
+int dm_get_table_device(struct mapped_device *md, dev_t dev, fmode_t mode,
+ struct dm_dev **result) {
+ int r;
+ struct table_device *td;
+
+ mutex_lock(&md->table_devices_lock);
+ td = find_table_device(&md->table_devices, dev, mode);
+ if (!td) {
+ td = kmalloc(sizeof(*td), GFP_KERNEL);
+ if (!td) {
+ mutex_unlock(&md->table_devices_lock);
+ return -ENOMEM;
+ }
+
+ td->dm_dev.mode = mode;
+ td->dm_dev.bdev = NULL;
+
+ if ((r = open_table_device(td, dev, md))) {
+ mutex_unlock(&md->table_devices_lock);
+ kfree(td);
+ return r;
+ }
+
+ format_dev_t(td->dm_dev.name, dev);
+
+ atomic_set(&td->count, 0);
+ list_add(&td->list, &md->table_devices);
+ }
+ atomic_inc(&td->count);
+ mutex_unlock(&md->table_devices_lock);
+
+ *result = &td->dm_dev;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(dm_get_table_device);
+
+void dm_put_table_device(struct mapped_device *md, struct dm_dev *d)
+{
+ struct table_device *td = container_of(d, struct table_device, dm_dev);
+
+ mutex_lock(&md->table_devices_lock);
+ if (atomic_dec_and_test(&td->count)) {
+ close_table_device(td, md);
+ list_del(&td->list);
+ kfree(td);
+ }
+ mutex_unlock(&md->table_devices_lock);
+}
+EXPORT_SYMBOL(dm_put_table_device);
+
+static void free_table_devices(struct list_head *devices)
+{
+ struct list_head *tmp, *next;
+
+ list_for_each_safe(tmp, next, devices) {
+ struct table_device *td = list_entry(tmp, struct table_device, list);
+
+ DMWARN("dm_destroy: %s still exists with %d references",
+ td->dm_dev.name, atomic_read(&td->count));
+ kfree(td);
+ }
+}
+
+/*
+ * Get the geometry associated with a dm device
+ */
+int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo)
+{
+ *geo = md->geometry;
+
+ return 0;
+}
+
+/*
+ * Set the geometry of a device.
+ */
+int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo)
+{
+ sector_t sz = (sector_t)geo->cylinders * geo->heads * geo->sectors;
+
+ if (geo->start > sz) {
+ DMWARN("Start sector is beyond the geometry limits.");
+ return -EINVAL;
+ }
+
+ md->geometry = *geo;
+
+ return 0;
+}
+
+/*-----------------------------------------------------------------
+ * CRUD START:
+ * A more elegant soln is in the works that uses the queue
+ * merge fn, unfortunately there are a couple of changes to
+ * the block layer that I want to make for this. So in the
+ * interests of getting something for people to use I give
+ * you this clearly demarcated crap.
+ *---------------------------------------------------------------*/
+
+static int __noflush_suspending(struct mapped_device *md)
+{
+ return test_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
+}
+
+/*
+ * Decrements the number of outstanding ios that a bio has been
+ * cloned into, completing the original io if necc.
+ */
+static void dec_pending(struct dm_io *io, int error)
+{
+ unsigned long flags;
+ int io_error;
+ struct bio *bio;
+ struct mapped_device *md = io->md;
+
+ /* Push-back supersedes any I/O errors */
+ if (unlikely(error)) {
+ spin_lock_irqsave(&io->endio_lock, flags);
+ if (!(io->error > 0 && __noflush_suspending(md)))
+ io->error = error;
+ spin_unlock_irqrestore(&io->endio_lock, flags);
+ }
+
+ if (atomic_dec_and_test(&io->io_count)) {
+ if (io->error == DM_ENDIO_REQUEUE) {
+ /*
+ * Target requested pushing back the I/O.
+ */
+ spin_lock_irqsave(&md->deferred_lock, flags);
+ if (__noflush_suspending(md))
+ bio_list_add_head(&md->deferred, io->bio);
+ else
+ /* noflush suspend was interrupted. */
+ io->error = -EIO;
+ spin_unlock_irqrestore(&md->deferred_lock, flags);
+ }
+
+ io_error = io->error;
+ bio = io->bio;
+ end_io_acct(io);
+ free_io(md, io);
+
+ if (io_error == DM_ENDIO_REQUEUE)
+ return;
+
+ if ((bio->bi_rw & REQ_FLUSH) && bio->bi_iter.bi_size) {
+ /*
+ * Preflush done for flush with data, reissue
+ * without REQ_FLUSH.
+ */
+ bio->bi_rw &= ~REQ_FLUSH;
+ queue_io(md, bio);
+ } else {
+ /* done with normal IO or empty flush */
+ trace_block_bio_complete(md->queue, bio, io_error);
+ bio_endio(bio, io_error);
+ }
+ }
+}
+
+static void disable_write_same(struct mapped_device *md)
+{
+ struct queue_limits *limits = dm_get_queue_limits(md);
+
+ /* device doesn't really support WRITE SAME, disable it */
+ limits->max_write_same_sectors = 0;
+}
+
+static void clone_endio(struct bio *bio, int error)
+{
+ int r = error;
+ struct dm_target_io *tio = container_of(bio, struct dm_target_io, clone);
+ struct dm_io *io = tio->io;
+ struct mapped_device *md = tio->io->md;
+ dm_endio_fn endio = tio->ti->type->end_io;
+
+ if (!bio_flagged(bio, BIO_UPTODATE) && !error)
+ error = -EIO;
+
+ if (endio) {
+ r = endio(tio->ti, bio, error);
+ if (r < 0 || r == DM_ENDIO_REQUEUE)
+ /*
+ * error and requeue request are handled
+ * in dec_pending().
+ */
+ error = r;
+ else if (r == DM_ENDIO_INCOMPLETE)
+ /* The target will handle the io */
+ return;
+ else if (r) {
+ DMWARN("unimplemented target endio return value: %d", r);
+ BUG();
+ }
+ }
+
+ if (unlikely(r == -EREMOTEIO && (bio->bi_rw & REQ_WRITE_SAME) &&
+ !bdev_get_queue(bio->bi_bdev)->limits.max_write_same_sectors))
+ disable_write_same(md);
+
+ free_tio(md, tio);
+ dec_pending(io, error);
+}
+
+/*
+ * Partial completion handling for request-based dm
+ */
+static void end_clone_bio(struct bio *clone, int error)
+{
+ struct dm_rq_clone_bio_info *info =
+ container_of(clone, struct dm_rq_clone_bio_info, clone);
+ struct dm_rq_target_io *tio = info->tio;
+ struct bio *bio = info->orig;
+ unsigned int nr_bytes = info->orig->bi_iter.bi_size;
+
+ bio_put(clone);
+
+ if (tio->error)
+ /*
+ * An error has already been detected on the request.
+ * Once error occurred, just let clone->end_io() handle
+ * the remainder.
+ */
+ return;
+ else if (error) {
+ /*
+ * Don't notice the error to the upper layer yet.
+ * The error handling decision is made by the target driver,
+ * when the request is completed.
+ */
+ tio->error = error;
+ return;
+ }
+
+ /*
+ * I/O for the bio successfully completed.
+ * Notice the data completion to the upper layer.
+ */
+
+ /*
+ * bios are processed from the head of the list.
+ * So the completing bio should always be rq->bio.
+ * If it's not, something wrong is happening.
+ */
+ if (tio->orig->bio != bio)
+ DMERR("bio completion is going in the middle of the request");
+
+ /*
+ * Update the original request.
+ * Do not use blk_end_request() here, because it may complete
+ * the original request before the clone, and break the ordering.
+ */
+ blk_update_request(tio->orig, 0, nr_bytes);
+}
+
+static struct dm_rq_target_io *tio_from_request(struct request *rq)
+{
+ return (rq->q->mq_ops ? blk_mq_rq_to_pdu(rq) : rq->special);
+}
+
+/*
+ * Don't touch any member of the md after calling this function because
+ * the md may be freed in dm_put() at the end of this function.
+ * Or do dm_get() before calling this function and dm_put() later.
+ */
+static void rq_completed(struct mapped_device *md, int rw, bool run_queue)
+{
+ int nr_requests_pending;
+
+ atomic_dec(&md->pending[rw]);
+
+ /* nudge anyone waiting on suspend queue */
+ nr_requests_pending = md_in_flight(md);
+ if (!nr_requests_pending)
+ wake_up(&md->wait);
+
+ /*
+ * Run this off this callpath, as drivers could invoke end_io while
+ * inside their request_fn (and holding the queue lock). Calling
+ * back into ->request_fn() could deadlock attempting to grab the
+ * queue lock again.
+ */
+ if (run_queue) {
+ if (md->queue->mq_ops)
+ blk_mq_run_hw_queues(md->queue, true);
+ else if (!nr_requests_pending ||
+ (nr_requests_pending >= md->queue->nr_congestion_on))
+ blk_run_queue_async(md->queue);
+ }
+
+ /*
+ * dm_put() must be at the end of this function. See the comment above
+ */
+ dm_put(md);
+}
+
+static void free_rq_clone(struct request *clone)
+{
+ struct dm_rq_target_io *tio = clone->end_io_data;
+ struct mapped_device *md = tio->md;
+
+ blk_rq_unprep_clone(clone);
+
+ if (md->type == DM_TYPE_MQ_REQUEST_BASED)
+ /* stacked on blk-mq queue(s) */
+ tio->ti->type->release_clone_rq(clone);
+ else if (!md->queue->mq_ops)
+ /* request_fn queue stacked on request_fn queue(s) */
+ free_clone_request(md, clone);
+ /*
+ * NOTE: for the blk-mq queue stacked on request_fn queue(s) case:
+ * no need to call free_clone_request() because we leverage blk-mq by
+ * allocating the clone at the end of the blk-mq pdu (see: clone_rq)
+ */
+
+ if (!md->queue->mq_ops)
+ free_rq_tio(tio);
+}
+
+/*
+ * Complete the clone and the original request.
+ * Must be called without clone's queue lock held,
+ * see end_clone_request() for more details.
+ */
+static void dm_end_request(struct request *clone, int error)
+{
+ int rw = rq_data_dir(clone);
+ struct dm_rq_target_io *tio = clone->end_io_data;
+ struct mapped_device *md = tio->md;
+ struct request *rq = tio->orig;
+
+ if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
+ rq->errors = clone->errors;
+ rq->resid_len = clone->resid_len;
+
+ if (rq->sense)
+ /*
+ * We are using the sense buffer of the original
+ * request.
+ * So setting the length of the sense data is enough.
+ */
+ rq->sense_len = clone->sense_len;
+ }
+
+ free_rq_clone(clone);
+ if (!rq->q->mq_ops)
+ blk_end_request_all(rq, error);
+ else
+ blk_mq_end_request(rq, error);
+ rq_completed(md, rw, true);
+}
+
+static void dm_unprep_request(struct request *rq)
+{
+ struct dm_rq_target_io *tio = tio_from_request(rq);
+ struct request *clone = tio->clone;
+
+ if (!rq->q->mq_ops) {
+ rq->special = NULL;
+ rq->cmd_flags &= ~REQ_DONTPREP;
+ }
+
+ if (clone)
+ free_rq_clone(clone);
+}
+
+/*
+ * Requeue the original request of a clone.
+ */
+static void old_requeue_request(struct request *rq)
+{
+ struct request_queue *q = rq->q;
+ unsigned long flags;
+
+ spin_lock_irqsave(q->queue_lock, flags);
+ blk_requeue_request(q, rq);
+ blk_run_queue_async(q);
+ spin_unlock_irqrestore(q->queue_lock, flags);
+}
+
+static void dm_requeue_unmapped_original_request(struct mapped_device *md,
+ struct request *rq)
+{
+ int rw = rq_data_dir(rq);
+
+ dm_unprep_request(rq);
+
+ if (!rq->q->mq_ops)
+ old_requeue_request(rq);
+ else {
+ blk_mq_requeue_request(rq);
+ blk_mq_kick_requeue_list(rq->q);
+ }
+
+ rq_completed(md, rw, false);
+}
+
+static void dm_requeue_unmapped_request(struct request *clone)
+{
+ struct dm_rq_target_io *tio = clone->end_io_data;
+
+ dm_requeue_unmapped_original_request(tio->md, tio->orig);
+}
+
+static void old_stop_queue(struct request_queue *q)
+{
+ unsigned long flags;
+
+ if (blk_queue_stopped(q))
+ return;
+
+ spin_lock_irqsave(q->queue_lock, flags);
+ blk_stop_queue(q);
+ spin_unlock_irqrestore(q->queue_lock, flags);
+}
+
+static void stop_queue(struct request_queue *q)
+{
+ if (!q->mq_ops)
+ old_stop_queue(q);
+ else
+ blk_mq_stop_hw_queues(q);
+}
+
+static void old_start_queue(struct request_queue *q)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(q->queue_lock, flags);
+ if (blk_queue_stopped(q))
+ blk_start_queue(q);
+ spin_unlock_irqrestore(q->queue_lock, flags);
+}
+
+static void start_queue(struct request_queue *q)
+{
+ if (!q->mq_ops)
+ old_start_queue(q);
+ else
+ blk_mq_start_stopped_hw_queues(q, true);
+}
+
+static void dm_done(struct request *clone, int error, bool mapped)
+{
+ int r = error;
+ struct dm_rq_target_io *tio = clone->end_io_data;
+ dm_request_endio_fn rq_end_io = NULL;
+
+ if (tio->ti) {
+ rq_end_io = tio->ti->type->rq_end_io;
+
+ if (mapped && rq_end_io)
+ r = rq_end_io(tio->ti, clone, error, &tio->info);
+ }
+
+ if (unlikely(r == -EREMOTEIO && (clone->cmd_flags & REQ_WRITE_SAME) &&
+ !clone->q->limits.max_write_same_sectors))
+ disable_write_same(tio->md);
+
+ if (r <= 0)
+ /* The target wants to complete the I/O */
+ dm_end_request(clone, r);
+ else if (r == DM_ENDIO_INCOMPLETE)
+ /* The target will handle the I/O */
+ return;
+ else if (r == DM_ENDIO_REQUEUE)
+ /* The target wants to requeue the I/O */
+ dm_requeue_unmapped_request(clone);
+ else {
+ DMWARN("unimplemented target endio return value: %d", r);
+ BUG();
+ }
+}
+
+/*
+ * Request completion handler for request-based dm
+ */
+static void dm_softirq_done(struct request *rq)
+{
+ bool mapped = true;
+ struct dm_rq_target_io *tio = tio_from_request(rq);
+ struct request *clone = tio->clone;
+ int rw;
+
+ if (!clone) {
+ rw = rq_data_dir(rq);
+ if (!rq->q->mq_ops) {
+ blk_end_request_all(rq, tio->error);
+ rq_completed(tio->md, rw, false);
+ free_rq_tio(tio);
+ } else {
+ blk_mq_end_request(rq, tio->error);
+ rq_completed(tio->md, rw, false);
+ }
+ return;
+ }
+
+ if (rq->cmd_flags & REQ_FAILED)
+ mapped = false;
+
+ dm_done(clone, tio->error, mapped);
+}
+
+/*
+ * Complete the clone and the original request with the error status
+ * through softirq context.
+ */
+static void dm_complete_request(struct request *rq, int error)
+{
+ struct dm_rq_target_io *tio = tio_from_request(rq);
+
+ tio->error = error;
+ blk_complete_request(rq);
+}
+
+/*
+ * Complete the not-mapped clone and the original request with the error status
+ * through softirq context.
+ * Target's rq_end_io() function isn't called.
+ * This may be used when the target's map_rq() or clone_and_map_rq() functions fail.
+ */
+static void dm_kill_unmapped_request(struct request *rq, int error)
+{
+ rq->cmd_flags |= REQ_FAILED;
+ dm_complete_request(rq, error);
+}
+
+/*
+ * Called with the clone's queue lock held (for non-blk-mq)
+ */
+static void end_clone_request(struct request *clone, int error)
+{
+ struct dm_rq_target_io *tio = clone->end_io_data;
+
+ if (!clone->q->mq_ops) {
+ /*
+ * For just cleaning up the information of the queue in which
+ * the clone was dispatched.
+ * The clone is *NOT* freed actually here because it is alloced
+ * from dm own mempool (REQ_ALLOCED isn't set).
+ */
+ __blk_put_request(clone->q, clone);
+ }
+
+ /*
+ * Actual request completion is done in a softirq context which doesn't
+ * hold the clone's queue lock. Otherwise, deadlock could occur because:
+ * - another request may be submitted by the upper level driver
+ * of the stacking during the completion
+ * - the submission which requires queue lock may be done
+ * against this clone's queue
+ */
+ dm_complete_request(tio->orig, error);
+}
+
+/*
+ * Return maximum size of I/O possible at the supplied sector up to the current
+ * target boundary.
+ */
+static sector_t max_io_len_target_boundary(sector_t sector, struct dm_target *ti)
+{
+ sector_t target_offset = dm_target_offset(ti, sector);
+
+ return ti->len - target_offset;
+}
+
+static sector_t max_io_len(sector_t sector, struct dm_target *ti)
+{
+ sector_t len = max_io_len_target_boundary(sector, ti);
+ sector_t offset, max_len;
+
+ /*
+ * Does the target need to split even further?
+ */
+ if (ti->max_io_len) {
+ offset = dm_target_offset(ti, sector);
+ if (unlikely(ti->max_io_len & (ti->max_io_len - 1)))
+ max_len = sector_div(offset, ti->max_io_len);
+ else
+ max_len = offset & (ti->max_io_len - 1);
+ max_len = ti->max_io_len - max_len;
+
+ if (len > max_len)
+ len = max_len;
+ }
+
+ return len;
+}
+
+int dm_set_target_max_io_len(struct dm_target *ti, sector_t len)
+{
+ if (len > UINT_MAX) {
+ DMERR("Specified maximum size of target IO (%llu) exceeds limit (%u)",
+ (unsigned long long)len, UINT_MAX);
+ ti->error = "Maximum size of target IO is too large";
+ return -EINVAL;
+ }
+
+ ti->max_io_len = (uint32_t) len;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(dm_set_target_max_io_len);
+
+/*
+ * A target may call dm_accept_partial_bio only from the map routine. It is
+ * allowed for all bio types except REQ_FLUSH.
+ *
+ * dm_accept_partial_bio informs the dm that the target only wants to process
+ * additional n_sectors sectors of the bio and the rest of the data should be
+ * sent in a next bio.
+ *
+ * A diagram that explains the arithmetics:
+ * +--------------------+---------------+-------+
+ * | 1 | 2 | 3 |
+ * +--------------------+---------------+-------+
+ *
+ * <-------------- *tio->len_ptr --------------->
+ * <------- bi_size ------->
+ * <-- n_sectors -->
+ *
+ * Region 1 was already iterated over with bio_advance or similar function.
+ * (it may be empty if the target doesn't use bio_advance)
+ * Region 2 is the remaining bio size that the target wants to process.
+ * (it may be empty if region 1 is non-empty, although there is no reason
+ * to make it empty)
+ * The target requires that region 3 is to be sent in the next bio.
+ *
+ * If the target wants to receive multiple copies of the bio (via num_*bios, etc),
+ * the partially processed part (the sum of regions 1+2) must be the same for all
+ * copies of the bio.
+ */
+void dm_accept_partial_bio(struct bio *bio, unsigned n_sectors)
+{
+ struct dm_target_io *tio = container_of(bio, struct dm_target_io, clone);
+ unsigned bi_size = bio->bi_iter.bi_size >> SECTOR_SHIFT;
+ BUG_ON(bio->bi_rw & REQ_FLUSH);
+ BUG_ON(bi_size > *tio->len_ptr);
+ BUG_ON(n_sectors > bi_size);
+ *tio->len_ptr -= bi_size - n_sectors;
+ bio->bi_iter.bi_size = n_sectors << SECTOR_SHIFT;
+}
+EXPORT_SYMBOL_GPL(dm_accept_partial_bio);
+
+static void __map_bio(struct dm_target_io *tio)
+{
+ int r;
+ sector_t sector;
+ struct mapped_device *md;
+ struct bio *clone = &tio->clone;
+ struct dm_target *ti = tio->ti;
+
+ clone->bi_end_io = clone_endio;
+
+ /*
+ * Map the clone. If r == 0 we don't need to do
+ * anything, the target has assumed ownership of
+ * this io.
+ */
+ atomic_inc(&tio->io->io_count);
+ sector = clone->bi_iter.bi_sector;
+ r = ti->type->map(ti, clone);
+ if (r == DM_MAPIO_REMAPPED) {
+ /* the bio has been remapped so dispatch it */
+
+ trace_block_bio_remap(bdev_get_queue(clone->bi_bdev), clone,
+ tio->io->bio->bi_bdev->bd_dev, sector);
+
+ generic_make_request(clone);
+ } else if (r < 0 || r == DM_MAPIO_REQUEUE) {
+ /* error the io and bail out, or requeue it if needed */
+ md = tio->io->md;
+ dec_pending(tio->io, r);
+ free_tio(md, tio);
+ } else if (r) {
+ DMWARN("unimplemented target map return value: %d", r);
+ BUG();
+ }
+}
+
+struct clone_info {
+ struct mapped_device *md;
+ struct dm_table *map;
+ struct bio *bio;
+ struct dm_io *io;
+ sector_t sector;
+ unsigned sector_count;
+};
+
+static void bio_setup_sector(struct bio *bio, sector_t sector, unsigned len)
+{
+ bio->bi_iter.bi_sector = sector;
+ bio->bi_iter.bi_size = to_bytes(len);
+}
+
+/*
+ * Creates a bio that consists of range of complete bvecs.
+ */
+static void clone_bio(struct dm_target_io *tio, struct bio *bio,
+ sector_t sector, unsigned len)
+{
+ struct bio *clone = &tio->clone;
+
+ __bio_clone_fast(clone, bio);
+
+ if (bio_integrity(bio))
+ bio_integrity_clone(clone, bio, GFP_NOIO);
+
+ bio_advance(clone, to_bytes(sector - clone->bi_iter.bi_sector));
+ clone->bi_iter.bi_size = to_bytes(len);
+
+ if (bio_integrity(bio))
+ bio_integrity_trim(clone, 0, len);
+}
+
+static struct dm_target_io *alloc_tio(struct clone_info *ci,
+ struct dm_target *ti,
+ unsigned target_bio_nr)
+{
+ struct dm_target_io *tio;
+ struct bio *clone;
+
+ clone = bio_alloc_bioset(GFP_NOIO, 0, ci->md->bs);
+ tio = container_of(clone, struct dm_target_io, clone);
+
+ tio->io = ci->io;
+ tio->ti = ti;
+ tio->target_bio_nr = target_bio_nr;
+
+ return tio;
+}
+
+static void __clone_and_map_simple_bio(struct clone_info *ci,
+ struct dm_target *ti,
+ unsigned target_bio_nr, unsigned *len)
+{
+ struct dm_target_io *tio = alloc_tio(ci, ti, target_bio_nr);
+ struct bio *clone = &tio->clone;
+
+ tio->len_ptr = len;
+
+ __bio_clone_fast(clone, ci->bio);
+ if (len)
+ bio_setup_sector(clone, ci->sector, *len);
+
+ __map_bio(tio);
+}
+
+static void __send_duplicate_bios(struct clone_info *ci, struct dm_target *ti,
+ unsigned num_bios, unsigned *len)
+{
+ unsigned target_bio_nr;
+
+ for (target_bio_nr = 0; target_bio_nr < num_bios; target_bio_nr++)
+ __clone_and_map_simple_bio(ci, ti, target_bio_nr, len);
+}
+
+static int __send_empty_flush(struct clone_info *ci)
+{
+ unsigned target_nr = 0;
+ struct dm_target *ti;
+
+ BUG_ON(bio_has_data(ci->bio));
+ while ((ti = dm_table_get_target(ci->map, target_nr++)))
+ __send_duplicate_bios(ci, ti, ti->num_flush_bios, NULL);
+
+ return 0;
+}
+
+static void __clone_and_map_data_bio(struct clone_info *ci, struct dm_target *ti,
+ sector_t sector, unsigned *len)
+{
+ struct bio *bio = ci->bio;
+ struct dm_target_io *tio;
+ unsigned target_bio_nr;
+ unsigned num_target_bios = 1;
+
+ /*
+ * Does the target want to receive duplicate copies of the bio?
+ */
+ if (bio_data_dir(bio) == WRITE && ti->num_write_bios)
+ num_target_bios = ti->num_write_bios(ti, bio);
+
+ for (target_bio_nr = 0; target_bio_nr < num_target_bios; target_bio_nr++) {
+ tio = alloc_tio(ci, ti, target_bio_nr);
+ tio->len_ptr = len;
+ clone_bio(tio, bio, sector, *len);
+ __map_bio(tio);
+ }
+}
+
+typedef unsigned (*get_num_bios_fn)(struct dm_target *ti);
+
+static unsigned get_num_discard_bios(struct dm_target *ti)
+{
+ return ti->num_discard_bios;
+}
+
+static unsigned get_num_write_same_bios(struct dm_target *ti)
+{
+ return ti->num_write_same_bios;
+}
+
+typedef bool (*is_split_required_fn)(struct dm_target *ti);
+
+static bool is_split_required_for_discard(struct dm_target *ti)
+{
+ return ti->split_discard_bios;
+}
+
+static int __send_changing_extent_only(struct clone_info *ci,
+ get_num_bios_fn get_num_bios,
+ is_split_required_fn is_split_required)
+{
+ struct dm_target *ti;
+ unsigned len;
+ unsigned num_bios;
+
+ do {
+ ti = dm_table_find_target(ci->map, ci->sector);
+ if (!dm_target_is_valid(ti))
+ return -EIO;
+
+ /*
+ * Even though the device advertised support for this type of
+ * request, that does not mean every target supports it, and
+ * reconfiguration might also have changed that since the
+ * check was performed.
+ */
+ num_bios = get_num_bios ? get_num_bios(ti) : 0;
+ if (!num_bios)
+ return -EOPNOTSUPP;
+
+ if (is_split_required && !is_split_required(ti))
+ len = min((sector_t)ci->sector_count, max_io_len_target_boundary(ci->sector, ti));
+ else
+ len = min((sector_t)ci->sector_count, max_io_len(ci->sector, ti));
+
+ __send_duplicate_bios(ci, ti, num_bios, &len);
+
+ ci->sector += len;
+ } while (ci->sector_count -= len);
+
+ return 0;
+}
+
+static int __send_discard(struct clone_info *ci)
+{
+ return __send_changing_extent_only(ci, get_num_discard_bios,
+ is_split_required_for_discard);
+}
+
+static int __send_write_same(struct clone_info *ci)
+{
+ return __send_changing_extent_only(ci, get_num_write_same_bios, NULL);
+}
+
+/*
+ * Select the correct strategy for processing a non-flush bio.
+ */
+static int __split_and_process_non_flush(struct clone_info *ci)
+{
+ struct bio *bio = ci->bio;
+ struct dm_target *ti;
+ unsigned len;
+
+ if (unlikely(bio->bi_rw & REQ_DISCARD))
+ return __send_discard(ci);
+ else if (unlikely(bio->bi_rw & REQ_WRITE_SAME))
+ return __send_write_same(ci);
+
+ ti = dm_table_find_target(ci->map, ci->sector);
+ if (!dm_target_is_valid(ti))
+ return -EIO;
+
+ len = min_t(sector_t, max_io_len(ci->sector, ti), ci->sector_count);
+
+ __clone_and_map_data_bio(ci, ti, ci->sector, &len);
+
+ ci->sector += len;
+ ci->sector_count -= len;
+
+ return 0;
+}
+
+/*
+ * Entry point to split a bio into clones and submit them to the targets.
+ */
+static void __split_and_process_bio(struct mapped_device *md,
+ struct dm_table *map, struct bio *bio)
+{
+ struct clone_info ci;
+ int error = 0;
+
+ if (unlikely(!map)) {
+ bio_io_error(bio);
+ return;
+ }
+
+ ci.map = map;
+ ci.md = md;
+ ci.io = alloc_io(md);
+ ci.io->error = 0;
+ atomic_set(&ci.io->io_count, 1);
+ ci.io->bio = bio;
+ ci.io->md = md;
+ spin_lock_init(&ci.io->endio_lock);
+ ci.sector = bio->bi_iter.bi_sector;
+
+ start_io_acct(ci.io);
+
+ if (bio->bi_rw & REQ_FLUSH) {
+ ci.bio = &ci.md->flush_bio;
+ ci.sector_count = 0;
+ error = __send_empty_flush(&ci);
+ /* dec_pending submits any data associated with flush */
+ } else {
+ ci.bio = bio;
+ ci.sector_count = bio_sectors(bio);
+ while (ci.sector_count && !error)
+ error = __split_and_process_non_flush(&ci);
+ }
+
+ /* drop the extra reference count */
+ dec_pending(ci.io, error);
+}
+/*-----------------------------------------------------------------
+ * CRUD END
+ *---------------------------------------------------------------*/
+
+static int dm_merge_bvec(struct request_queue *q,
+ struct bvec_merge_data *bvm,
+ struct bio_vec *biovec)
+{
+ struct mapped_device *md = q->queuedata;
+ struct dm_table *map = dm_get_live_table_fast(md);
+ struct dm_target *ti;
+ sector_t max_sectors, max_size = 0;
+
+ if (unlikely(!map))
+ goto out;
+
+ ti = dm_table_find_target(map, bvm->bi_sector);
+ if (!dm_target_is_valid(ti))
+ goto out;
+
+ /*
+ * Find maximum amount of I/O that won't need splitting
+ */
+ max_sectors = min(max_io_len(bvm->bi_sector, ti),
+ (sector_t) queue_max_sectors(q));
+ max_size = (max_sectors << SECTOR_SHIFT) - bvm->bi_size;
+
+ /*
+ * FIXME: this stop-gap fix _must_ be cleaned up (by passing a sector_t
+ * to the targets' merge function since it holds sectors not bytes).
+ * Just doing this as an interim fix for stable@ because the more
+ * comprehensive cleanup of switching to sector_t will impact every
+ * DM target that implements a ->merge hook.
+ */
+ if (max_size > INT_MAX)
+ max_size = INT_MAX;
+
+ /*
+ * merge_bvec_fn() returns number of bytes
+ * it can accept at this offset
+ * max is precomputed maximal io size
+ */
+ if (max_size && ti->type->merge)
+ max_size = ti->type->merge(ti, bvm, biovec, (int) max_size);
+ /*
+ * If the target doesn't support merge method and some of the devices
+ * provided their merge_bvec method (we know this by looking for the
+ * max_hw_sectors that dm_set_device_limits may set), then we can't
+ * allow bios with multiple vector entries. So always set max_size
+ * to 0, and the code below allows just one page.
+ */
+ else if (queue_max_hw_sectors(q) <= PAGE_SIZE >> 9)
+ max_size = 0;
+
+out:
+ dm_put_live_table_fast(md);
+ /*
+ * Always allow an entire first page
+ */
+ if (max_size <= biovec->bv_len && !(bvm->bi_size >> SECTOR_SHIFT))
+ max_size = biovec->bv_len;
+
+ return max_size;
+}
+
+/*
+ * The request function that just remaps the bio built up by
+ * dm_merge_bvec.
+ */
+static void dm_make_request(struct request_queue *q, struct bio *bio)
+{
+ int rw = bio_data_dir(bio);
+ struct mapped_device *md = q->queuedata;
+ int srcu_idx;
+ struct dm_table *map;
+
+ map = dm_get_live_table(md, &srcu_idx);
+
+ generic_start_io_acct(rw, bio_sectors(bio), &dm_disk(md)->part0);
+
+ /* if we're suspended, we have to queue this io for later */
+ if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags))) {
+ dm_put_live_table(md, srcu_idx);
+
+ if (bio_rw(bio) != READA)
+ queue_io(md, bio);
+ else
+ bio_io_error(bio);
+ return;
+ }
+
+ __split_and_process_bio(md, map, bio);
+ dm_put_live_table(md, srcu_idx);
+ return;
+}
+
+int dm_request_based(struct mapped_device *md)
+{
+ return blk_queue_stackable(md->queue);
+}
+
+static void dm_dispatch_clone_request(struct request *clone, struct request *rq)
+{
+ int r;
+
+ if (blk_queue_io_stat(clone->q))
+ clone->cmd_flags |= REQ_IO_STAT;
+
+ clone->start_time = jiffies;
+ r = blk_insert_cloned_request(clone->q, clone);
+ if (r)
+ /* must complete clone in terms of original request */
+ dm_complete_request(rq, r);
+}
+
+static int dm_rq_bio_constructor(struct bio *bio, struct bio *bio_orig,
+ void *data)
+{
+ struct dm_rq_target_io *tio = data;
+ struct dm_rq_clone_bio_info *info =
+ container_of(bio, struct dm_rq_clone_bio_info, clone);
+
+ info->orig = bio_orig;
+ info->tio = tio;
+ bio->bi_end_io = end_clone_bio;
+
+ return 0;
+}
+
+static int setup_clone(struct request *clone, struct request *rq,
+ struct dm_rq_target_io *tio, gfp_t gfp_mask)
+{
+ int r;
+
+ r = blk_rq_prep_clone(clone, rq, tio->md->bs, gfp_mask,
+ dm_rq_bio_constructor, tio);
+ if (r)
+ return r;
+
+ clone->cmd = rq->cmd;
+ clone->cmd_len = rq->cmd_len;
+ clone->sense = rq->sense;
+ clone->end_io = end_clone_request;
+ clone->end_io_data = tio;
+
+ tio->clone = clone;
+
+ return 0;
+}
+
+static struct request *clone_rq(struct request *rq, struct mapped_device *md,
+ struct dm_rq_target_io *tio, gfp_t gfp_mask)
+{
+ /*
+ * Do not allocate a clone if tio->clone was already set
+ * (see: dm_mq_queue_rq).
+ */
+ bool alloc_clone = !tio->clone;
+ struct request *clone;
+
+ if (alloc_clone) {
+ clone = alloc_clone_request(md, gfp_mask);
+ if (!clone)
+ return NULL;
+ } else
+ clone = tio->clone;
+
+ blk_rq_init(NULL, clone);
+ if (setup_clone(clone, rq, tio, gfp_mask)) {
+ /* -ENOMEM */
+ if (alloc_clone)
+ free_clone_request(md, clone);
+ return NULL;
+ }
+
+ return clone;
+}
+
+static void map_tio_request(struct kthread_work *work);
+
+static void init_tio(struct dm_rq_target_io *tio, struct request *rq,
+ struct mapped_device *md)
+{
+ tio->md = md;
+ tio->ti = NULL;
+ tio->clone = NULL;
+ tio->orig = rq;
+ tio->error = 0;
+ memset(&tio->info, 0, sizeof(tio->info));
+ if (md->kworker_task)
+ init_kthread_work(&tio->work, map_tio_request);
+}
+
+static struct dm_rq_target_io *prep_tio(struct request *rq,
+ struct mapped_device *md, gfp_t gfp_mask)
+{
+ struct dm_rq_target_io *tio;
+ int srcu_idx;
+ struct dm_table *table;
+
+ tio = alloc_rq_tio(md, gfp_mask);
+ if (!tio)
+ return NULL;
+
+ init_tio(tio, rq, md);
+
+ table = dm_get_live_table(md, &srcu_idx);
+ if (!dm_table_mq_request_based(table)) {
+ if (!clone_rq(rq, md, tio, gfp_mask)) {
+ dm_put_live_table(md, srcu_idx);
+ free_rq_tio(tio);
+ return NULL;
+ }
+ }
+ dm_put_live_table(md, srcu_idx);
+
+ return tio;
+}
+
+/*
+ * Called with the queue lock held.
+ */
+static int dm_prep_fn(struct request_queue *q, struct request *rq)
+{
+ struct mapped_device *md = q->queuedata;
+ struct dm_rq_target_io *tio;
+
+ if (unlikely(rq->special)) {
+ DMWARN("Already has something in rq->special.");
+ return BLKPREP_KILL;
+ }
+
+ tio = prep_tio(rq, md, GFP_ATOMIC);
+ if (!tio)
+ return BLKPREP_DEFER;
+
+ rq->special = tio;
+ rq->cmd_flags |= REQ_DONTPREP;
+
+ return BLKPREP_OK;
+}
+
+/*
+ * Returns:
+ * 0 : the request has been processed
+ * DM_MAPIO_REQUEUE : the original request needs to be requeued
+ * < 0 : the request was completed due to failure
+ */
+static int map_request(struct dm_rq_target_io *tio, struct request *rq,
+ struct mapped_device *md)
+{
+ int r;
+ struct dm_target *ti = tio->ti;
+ struct request *clone = NULL;
+
+ if (tio->clone) {
+ clone = tio->clone;
+ r = ti->type->map_rq(ti, clone, &tio->info);
+ } else {
+ r = ti->type->clone_and_map_rq(ti, rq, &tio->info, &clone);
+ if (r < 0) {
+ /* The target wants to complete the I/O */
+ dm_kill_unmapped_request(rq, r);
+ return r;
+ }
+ if (r != DM_MAPIO_REMAPPED)
+ return r;
+ if (setup_clone(clone, rq, tio, GFP_ATOMIC)) {
+ /* -ENOMEM */
+ ti->type->release_clone_rq(clone);
+ return DM_MAPIO_REQUEUE;
+ }
+ }
+
+ switch (r) {
+ case DM_MAPIO_SUBMITTED:
+ /* The target has taken the I/O to submit by itself later */
+ break;
+ case DM_MAPIO_REMAPPED:
+ /* The target has remapped the I/O so dispatch it */
+ trace_block_rq_remap(clone->q, clone, disk_devt(dm_disk(md)),
+ blk_rq_pos(rq));
+ dm_dispatch_clone_request(clone, rq);
+ break;
+ case DM_MAPIO_REQUEUE:
+ /* The target wants to requeue the I/O */
+ dm_requeue_unmapped_request(clone);
+ break;
+ default:
+ if (r > 0) {
+ DMWARN("unimplemented target map return value: %d", r);
+ BUG();
+ }
+
+ /* The target wants to complete the I/O */
+ dm_kill_unmapped_request(rq, r);
+ return r;
+ }
+
+ return 0;
+}
+
+static void map_tio_request(struct kthread_work *work)
+{
+ struct dm_rq_target_io *tio = container_of(work, struct dm_rq_target_io, work);
+ struct request *rq = tio->orig;
+ struct mapped_device *md = tio->md;
+
+ if (map_request(tio, rq, md) == DM_MAPIO_REQUEUE)
+ dm_requeue_unmapped_original_request(md, rq);
+}
+
+static void dm_start_request(struct mapped_device *md, struct request *orig)
+{
+ if (!orig->q->mq_ops)
+ blk_start_request(orig);
+ else
+ blk_mq_start_request(orig);
+ atomic_inc(&md->pending[rq_data_dir(orig)]);
+
+ if (md->seq_rq_merge_deadline_usecs) {
+ md->last_rq_pos = rq_end_sector(orig);
+ md->last_rq_rw = rq_data_dir(orig);
+ md->last_rq_start_time = ktime_get();
+ }
+
+ /*
+ * Hold the md reference here for the in-flight I/O.
+ * We can't rely on the reference count by device opener,
+ * because the device may be closed during the request completion
+ * when all bios are completed.
+ * See the comment in rq_completed() too.
+ */
+ dm_get(md);
+}
+
+#define MAX_SEQ_RQ_MERGE_DEADLINE_USECS 100000
+
+ssize_t dm_attr_rq_based_seq_io_merge_deadline_show(struct mapped_device *md, char *buf)
+{
+ return sprintf(buf, "%u\n", md->seq_rq_merge_deadline_usecs);
+}
+
+ssize_t dm_attr_rq_based_seq_io_merge_deadline_store(struct mapped_device *md,
+ const char *buf, size_t count)
+{
+ unsigned deadline;
+
+ if (!dm_request_based(md) || md->use_blk_mq)
+ return count;
+
+ if (kstrtouint(buf, 10, &deadline))
+ return -EINVAL;
+
+ if (deadline > MAX_SEQ_RQ_MERGE_DEADLINE_USECS)
+ deadline = MAX_SEQ_RQ_MERGE_DEADLINE_USECS;
+
+ md->seq_rq_merge_deadline_usecs = deadline;
+
+ return count;
+}
+
+static bool dm_request_peeked_before_merge_deadline(struct mapped_device *md)
+{
+ ktime_t kt_deadline;
+
+ if (!md->seq_rq_merge_deadline_usecs)
+ return false;
+
+ kt_deadline = ns_to_ktime((u64)md->seq_rq_merge_deadline_usecs * NSEC_PER_USEC);
+ kt_deadline = ktime_add_safe(md->last_rq_start_time, kt_deadline);
+
+ return !ktime_after(ktime_get(), kt_deadline);
+}
+
+/*
+ * q->request_fn for request-based dm.
+ * Called with the queue lock held.
+ */
+static void dm_request_fn(struct request_queue *q)
+{
+ struct mapped_device *md = q->queuedata;
+ int srcu_idx;
+ struct dm_table *map = dm_get_live_table(md, &srcu_idx);
+ struct dm_target *ti;
+ struct request *rq;
+ struct dm_rq_target_io *tio;
+ sector_t pos;
+
+ /*
+ * For suspend, check blk_queue_stopped() and increment
+ * ->pending within a single queue_lock not to increment the
+ * number of in-flight I/Os after the queue is stopped in
+ * dm_suspend().
+ */
+ while (!blk_queue_stopped(q)) {
+ rq = blk_peek_request(q);
+ if (!rq)
+ goto out;
+
+ /* always use block 0 to find the target for flushes for now */
+ pos = 0;
+ if (!(rq->cmd_flags & REQ_FLUSH))
+ pos = blk_rq_pos(rq);
+
+ ti = dm_table_find_target(map, pos);
+ if (!dm_target_is_valid(ti)) {
+ /*
+ * Must perform setup, that rq_completed() requires,
+ * before calling dm_kill_unmapped_request
+ */
+ DMERR_LIMIT("request attempted access beyond the end of device");
+ dm_start_request(md, rq);
+ dm_kill_unmapped_request(rq, -EIO);
+ continue;
+ }
+
+ if (dm_request_peeked_before_merge_deadline(md) &&
+ md_in_flight(md) && rq->bio && rq->bio->bi_vcnt == 1 &&
+ md->last_rq_pos == pos && md->last_rq_rw == rq_data_dir(rq))
+ goto delay_and_out;
+
+ if (ti->type->busy && ti->type->busy(ti))
+ goto delay_and_out;
+
+ dm_start_request(md, rq);
+
+ tio = tio_from_request(rq);
+ /* Establish tio->ti before queuing work (map_tio_request) */
+ tio->ti = ti;
+ queue_kthread_work(&md->kworker, &tio->work);
+ BUG_ON_NONRT(!irqs_disabled());
+ }
+
+ goto out;
+
+delay_and_out:
+ blk_delay_queue(q, HZ / 100);
+out:
+ dm_put_live_table(md, srcu_idx);
+}
+
+static int dm_any_congested(void *congested_data, int bdi_bits)
+{
+ int r = bdi_bits;
+ struct mapped_device *md = congested_data;
+ struct dm_table *map;
+
+ if (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) {
+ map = dm_get_live_table_fast(md);
+ if (map) {
+ /*
+ * Request-based dm cares about only own queue for
+ * the query about congestion status of request_queue
+ */
+ if (dm_request_based(md))
+ r = md->queue->backing_dev_info.state &
+ bdi_bits;
+ else
+ r = dm_table_any_congested(map, bdi_bits);
+ }
+ dm_put_live_table_fast(md);
+ }
+
+ return r;
+}
+
+/*-----------------------------------------------------------------
+ * An IDR is used to keep track of allocated minor numbers.
+ *---------------------------------------------------------------*/
+static void free_minor(int minor)
+{
+ spin_lock(&_minor_lock);
+ idr_remove(&_minor_idr, minor);
+ spin_unlock(&_minor_lock);
+}
+
+/*
+ * See if the device with a specific minor # is free.
+ */
+static int specific_minor(int minor)
+{
+ int r;
+
+ if (minor >= (1 << MINORBITS))
+ return -EINVAL;
+
+ idr_preload(GFP_KERNEL);
+ spin_lock(&_minor_lock);
+
+ r = idr_alloc(&_minor_idr, MINOR_ALLOCED, minor, minor + 1, GFP_NOWAIT);
+
+ spin_unlock(&_minor_lock);
+ idr_preload_end();
+ if (r < 0)
+ return r == -ENOSPC ? -EBUSY : r;
+ return 0;
+}
+
+static int next_free_minor(int *minor)
+{
+ int r;
+
+ idr_preload(GFP_KERNEL);
+ spin_lock(&_minor_lock);
+
+ r = idr_alloc(&_minor_idr, MINOR_ALLOCED, 0, 1 << MINORBITS, GFP_NOWAIT);
+
+ spin_unlock(&_minor_lock);
+ idr_preload_end();
+ if (r < 0)
+ return r;
+ *minor = r;
+ return 0;
+}
+
+static const struct block_device_operations dm_blk_dops;
+
+static void dm_wq_work(struct work_struct *work);
+
+static void dm_init_md_queue(struct mapped_device *md)
+{
+ /*
+ * Request-based dm devices cannot be stacked on top of bio-based dm
+ * devices. The type of this dm device may not have been decided yet.
+ * The type is decided at the first table loading time.
+ * To prevent problematic device stacking, clear the queue flag
+ * for request stacking support until then.
+ *
+ * This queue is new, so no concurrency on the queue_flags.
+ */
+ queue_flag_clear_unlocked(QUEUE_FLAG_STACKABLE, md->queue);
+}
+
+static void dm_init_old_md_queue(struct mapped_device *md)
+{
+ md->use_blk_mq = false;
+ dm_init_md_queue(md);
+
+ /*
+ * Initialize aspects of queue that aren't relevant for blk-mq
+ */
+ md->queue->queuedata = md;
+ md->queue->backing_dev_info.congested_fn = dm_any_congested;
+ md->queue->backing_dev_info.congested_data = md;
+
+ blk_queue_bounce_limit(md->queue, BLK_BOUNCE_ANY);
+}
+
+/*
+ * Allocate and initialise a blank device with a given minor.
+ */
+static struct mapped_device *alloc_dev(int minor)
+{
+ int r;
+ struct mapped_device *md = kzalloc(sizeof(*md), GFP_KERNEL);
+ void *old_md;
+
+ if (!md) {
+ DMWARN("unable to allocate device, out of memory.");
+ return NULL;
+ }
+
+ if (!try_module_get(THIS_MODULE))
+ goto bad_module_get;
+
+ /* get a minor number for the dev */
+ if (minor == DM_ANY_MINOR)
+ r = next_free_minor(&minor);
+ else
+ r = specific_minor(minor);
+ if (r < 0)
+ goto bad_minor;
+
+ r = init_srcu_struct(&md->io_barrier);
+ if (r < 0)
+ goto bad_io_barrier;
+
+ md->use_blk_mq = use_blk_mq;
+ md->type = DM_TYPE_NONE;
+ mutex_init(&md->suspend_lock);
+ mutex_init(&md->type_lock);
+ mutex_init(&md->table_devices_lock);
+ spin_lock_init(&md->deferred_lock);
+ atomic_set(&md->holders, 1);
+ atomic_set(&md->open_count, 0);
+ atomic_set(&md->event_nr, 0);
+ atomic_set(&md->uevent_seq, 0);
+ INIT_LIST_HEAD(&md->uevent_list);
+ INIT_LIST_HEAD(&md->table_devices);
+ spin_lock_init(&md->uevent_lock);
+
+ md->queue = blk_alloc_queue(GFP_KERNEL);
+ if (!md->queue)
+ goto bad_queue;
+
+ dm_init_md_queue(md);
+
+ md->disk = alloc_disk(1);
+ if (!md->disk)
+ goto bad_disk;
+
+ atomic_set(&md->pending[0], 0);
+ atomic_set(&md->pending[1], 0);
+ init_waitqueue_head(&md->wait);
+ INIT_WORK(&md->work, dm_wq_work);
+ init_waitqueue_head(&md->eventq);
+ init_completion(&md->kobj_holder.completion);
+ md->kworker_task = NULL;
+
+ md->disk->major = _major;
+ md->disk->first_minor = minor;
+ md->disk->fops = &dm_blk_dops;
+ md->disk->queue = md->queue;
+ md->disk->private_data = md;
+ sprintf(md->disk->disk_name, "dm-%d", minor);
+ add_disk(md->disk);
+ format_dev_t(md->name, MKDEV(_major, minor));
+
+ md->wq = alloc_workqueue("kdmflush", WQ_MEM_RECLAIM, 0);
+ if (!md->wq)
+ goto bad_thread;
+
+ md->bdev = bdget_disk(md->disk, 0);
+ if (!md->bdev)
+ goto bad_bdev;
+
+ bio_init(&md->flush_bio);
+ md->flush_bio.bi_bdev = md->bdev;
+ md->flush_bio.bi_rw = WRITE_FLUSH;
+
+ dm_stats_init(&md->stats);
+
+ /* Populate the mapping, nobody knows we exist yet */
+ spin_lock(&_minor_lock);
+ old_md = idr_replace(&_minor_idr, md, minor);
+ spin_unlock(&_minor_lock);
+
+ BUG_ON(old_md != MINOR_ALLOCED);
+
+ return md;
+
+bad_bdev:
+ destroy_workqueue(md->wq);
+bad_thread:
+ del_gendisk(md->disk);
+ put_disk(md->disk);
+bad_disk:
+ blk_cleanup_queue(md->queue);
+bad_queue:
+ cleanup_srcu_struct(&md->io_barrier);
+bad_io_barrier:
+ free_minor(minor);
+bad_minor:
+ module_put(THIS_MODULE);
+bad_module_get:
+ kfree(md);
+ return NULL;
+}
+
+static void unlock_fs(struct mapped_device *md);
+
+static void free_dev(struct mapped_device *md)
+{
+ int minor = MINOR(disk_devt(md->disk));
+
+ unlock_fs(md);
+ destroy_workqueue(md->wq);
+
+ if (md->kworker_task)
+ kthread_stop(md->kworker_task);
+ if (md->io_pool)
+ mempool_destroy(md->io_pool);
+ if (md->rq_pool)
+ mempool_destroy(md->rq_pool);
+ if (md->bs)
+ bioset_free(md->bs);
+
+ cleanup_srcu_struct(&md->io_barrier);
+ free_table_devices(&md->table_devices);
+ dm_stats_cleanup(&md->stats);
+
+ spin_lock(&_minor_lock);
+ md->disk->private_data = NULL;
+ spin_unlock(&_minor_lock);
+ if (blk_get_integrity(md->disk))
+ blk_integrity_unregister(md->disk);
+ del_gendisk(md->disk);
+ put_disk(md->disk);
+ blk_cleanup_queue(md->queue);
+ if (md->use_blk_mq)
+ blk_mq_free_tag_set(&md->tag_set);
+ bdput(md->bdev);
+ free_minor(minor);
+
+ module_put(THIS_MODULE);
+ kfree(md);
+}
+
+static void __bind_mempools(struct mapped_device *md, struct dm_table *t)
+{
+ struct dm_md_mempools *p = dm_table_get_md_mempools(t);
+
+ if (md->bs) {
+ /* The md already has necessary mempools. */
+ if (dm_table_get_type(t) == DM_TYPE_BIO_BASED) {
+ /*
+ * Reload bioset because front_pad may have changed
+ * because a different table was loaded.
+ */
+ bioset_free(md->bs);
+ md->bs = p->bs;
+ p->bs = NULL;
+ }
+ /*
+ * There's no need to reload with request-based dm
+ * because the size of front_pad doesn't change.
+ * Note for future: If you are to reload bioset,
+ * prep-ed requests in the queue may refer
+ * to bio from the old bioset, so you must walk
+ * through the queue to unprep.
+ */
+ goto out;
+ }
+
+ BUG_ON(!p || md->io_pool || md->rq_pool || md->bs);
+
+ md->io_pool = p->io_pool;
+ p->io_pool = NULL;
+ md->rq_pool = p->rq_pool;
+ p->rq_pool = NULL;
+ md->bs = p->bs;
+ p->bs = NULL;
+
+out:
+ /* mempool bind completed, no longer need any mempools in the table */
+ dm_table_free_md_mempools(t);
+}
+
+/*
+ * Bind a table to the device.
+ */
+static void event_callback(void *context)
+{
+ unsigned long flags;
+ LIST_HEAD(uevents);
+ struct mapped_device *md = (struct mapped_device *) context;
+
+ spin_lock_irqsave(&md->uevent_lock, flags);
+ list_splice_init(&md->uevent_list, &uevents);
+ spin_unlock_irqrestore(&md->uevent_lock, flags);
+
+ dm_send_uevents(&uevents, &disk_to_dev(md->disk)->kobj);
+
+ atomic_inc(&md->event_nr);
+ wake_up(&md->eventq);
+}
+
+/*
+ * Protected by md->suspend_lock obtained by dm_swap_table().
+ */
+static void __set_size(struct mapped_device *md, sector_t size)
+{
+ set_capacity(md->disk, size);
+
+ i_size_write(md->bdev->bd_inode, (loff_t)size << SECTOR_SHIFT);
+}
+
+/*
+ * Return 1 if the queue has a compulsory merge_bvec_fn function.
+ *
+ * If this function returns 0, then the device is either a non-dm
+ * device without a merge_bvec_fn, or it is a dm device that is
+ * able to split any bios it receives that are too big.
+ */
+int dm_queue_merge_is_compulsory(struct request_queue *q)
+{
+ struct mapped_device *dev_md;
+
+ if (!q->merge_bvec_fn)
+ return 0;
+
+ if (q->make_request_fn == dm_make_request) {
+ dev_md = q->queuedata;
+ if (test_bit(DMF_MERGE_IS_OPTIONAL, &dev_md->flags))
+ return 0;
+ }
+
+ return 1;
+}
+
+static int dm_device_merge_is_compulsory(struct dm_target *ti,
+ struct dm_dev *dev, sector_t start,
+ sector_t len, void *data)
+{
+ struct block_device *bdev = dev->bdev;
+ struct request_queue *q = bdev_get_queue(bdev);
+
+ return dm_queue_merge_is_compulsory(q);
+}
+
+/*
+ * Return 1 if it is acceptable to ignore merge_bvec_fn based
+ * on the properties of the underlying devices.
+ */
+static int dm_table_merge_is_optional(struct dm_table *table)
+{
+ unsigned i = 0;
+ struct dm_target *ti;
+
+ while (i < dm_table_get_num_targets(table)) {
+ ti = dm_table_get_target(table, i++);
+
+ if (ti->type->iterate_devices &&
+ ti->type->iterate_devices(ti, dm_device_merge_is_compulsory, NULL))
+ return 0;
+ }
+
+ return 1;
+}
+
+/*
+ * Returns old map, which caller must destroy.
+ */
+static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t,
+ struct queue_limits *limits)
+{
+ struct dm_table *old_map;
+ struct request_queue *q = md->queue;
+ sector_t size;
+ int merge_is_optional;
+
+ size = dm_table_get_size(t);
+
+ /*
+ * Wipe any geometry if the size of the table changed.
+ */
+ if (size != dm_get_size(md))
+ memset(&md->geometry, 0, sizeof(md->geometry));
+
+ __set_size(md, size);
+
+ dm_table_event_callback(t, event_callback, md);
+
+ /*
+ * The queue hasn't been stopped yet, if the old table type wasn't
+ * for request-based during suspension. So stop it to prevent
+ * I/O mapping before resume.
+ * This must be done before setting the queue restrictions,
+ * because request-based dm may be run just after the setting.
+ */
+ if (dm_table_request_based(t))
+ stop_queue(q);
+
+ __bind_mempools(md, t);
+
+ merge_is_optional = dm_table_merge_is_optional(t);
+
+ old_map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock));
+ rcu_assign_pointer(md->map, t);
+ md->immutable_target_type = dm_table_get_immutable_target_type(t);
+
+ dm_table_set_restrictions(t, q, limits);
+ if (merge_is_optional)
+ set_bit(DMF_MERGE_IS_OPTIONAL, &md->flags);
+ else
+ clear_bit(DMF_MERGE_IS_OPTIONAL, &md->flags);
+ if (old_map)
+ dm_sync_table(md);
+
+ return old_map;
+}
+
+/*
+ * Returns unbound table for the caller to free.
+ */
+static struct dm_table *__unbind(struct mapped_device *md)
+{
+ struct dm_table *map = rcu_dereference_protected(md->map, 1);
+
+ if (!map)
+ return NULL;
+
+ dm_table_event_callback(map, NULL, NULL);
+ RCU_INIT_POINTER(md->map, NULL);
+ dm_sync_table(md);
+
+ return map;
+}
+
+/*
+ * Constructor for a new device.
+ */
+int dm_create(int minor, struct mapped_device **result)
+{
+ struct mapped_device *md;
+
+ md = alloc_dev(minor);
+ if (!md)
+ return -ENXIO;
+
+ dm_sysfs_init(md);
+
+ *result = md;
+ return 0;
+}
+
+/*
+ * Functions to manage md->type.
+ * All are required to hold md->type_lock.
+ */
+void dm_lock_md_type(struct mapped_device *md)
+{
+ mutex_lock(&md->type_lock);
+}
+
+void dm_unlock_md_type(struct mapped_device *md)
+{
+ mutex_unlock(&md->type_lock);
+}
+
+void dm_set_md_type(struct mapped_device *md, unsigned type)
+{
+ BUG_ON(!mutex_is_locked(&md->type_lock));
+ md->type = type;
+}
+
+unsigned dm_get_md_type(struct mapped_device *md)
+{
+ BUG_ON(!mutex_is_locked(&md->type_lock));
+ return md->type;
+}
+
+struct target_type *dm_get_immutable_target_type(struct mapped_device *md)
+{
+ return md->immutable_target_type;
+}
+
+/*
+ * The queue_limits are only valid as long as you have a reference
+ * count on 'md'.
+ */
+struct queue_limits *dm_get_queue_limits(struct mapped_device *md)
+{
+ BUG_ON(!atomic_read(&md->holders));
+ return &md->queue->limits;
+}
+EXPORT_SYMBOL_GPL(dm_get_queue_limits);
+
+static void init_rq_based_worker_thread(struct mapped_device *md)
+{
+ /* Initialize the request-based DM worker thread */
+ init_kthread_worker(&md->kworker);
+ md->kworker_task = kthread_run(kthread_worker_fn, &md->kworker,
+ "kdmwork-%s", dm_device_name(md));
+}
+
+/*
+ * Fully initialize a request-based queue (->elevator, ->request_fn, etc).
+ */
+static int dm_init_request_based_queue(struct mapped_device *md)
+{
+ struct request_queue *q = NULL;
+
+ /* Fully initialize the queue */
+ q = blk_init_allocated_queue(md->queue, dm_request_fn, NULL);
+ if (!q)
+ return -EINVAL;
+
+ /* disable dm_request_fn's merge heuristic by default */
+ md->seq_rq_merge_deadline_usecs = 0;
+
+ md->queue = q;
+ dm_init_old_md_queue(md);
+ blk_queue_softirq_done(md->queue, dm_softirq_done);
+ blk_queue_prep_rq(md->queue, dm_prep_fn);
+
+ init_rq_based_worker_thread(md);
+
+ elv_register_queue(md->queue);
+
+ return 0;
+}
+
+static int dm_mq_init_request(void *data, struct request *rq,
+ unsigned int hctx_idx, unsigned int request_idx,
+ unsigned int numa_node)
+{
+ struct mapped_device *md = data;
+ struct dm_rq_target_io *tio = blk_mq_rq_to_pdu(rq);
+
+ /*
+ * Must initialize md member of tio, otherwise it won't
+ * be available in dm_mq_queue_rq.
+ */
+ tio->md = md;
+
+ return 0;
+}
+
+static int dm_mq_queue_rq(struct blk_mq_hw_ctx *hctx,
+ const struct blk_mq_queue_data *bd)
+{
+ struct request *rq = bd->rq;
+ struct dm_rq_target_io *tio = blk_mq_rq_to_pdu(rq);
+ struct mapped_device *md = tio->md;
+ int srcu_idx;
+ struct dm_table *map = dm_get_live_table(md, &srcu_idx);
+ struct dm_target *ti;
+ sector_t pos;
+
+ /* always use block 0 to find the target for flushes for now */
+ pos = 0;
+ if (!(rq->cmd_flags & REQ_FLUSH))
+ pos = blk_rq_pos(rq);
+
+ ti = dm_table_find_target(map, pos);
+ if (!dm_target_is_valid(ti)) {
+ dm_put_live_table(md, srcu_idx);
+ DMERR_LIMIT("request attempted access beyond the end of device");
+ /*
+ * Must perform setup, that rq_completed() requires,
+ * before returning BLK_MQ_RQ_QUEUE_ERROR
+ */
+ dm_start_request(md, rq);
+ return BLK_MQ_RQ_QUEUE_ERROR;
+ }
+ dm_put_live_table(md, srcu_idx);
+
+ if (ti->type->busy && ti->type->busy(ti))
+ return BLK_MQ_RQ_QUEUE_BUSY;
+
+ dm_start_request(md, rq);
+
+ /* Init tio using md established in .init_request */
+ init_tio(tio, rq, md);
+
+ /*
+ * Establish tio->ti before queuing work (map_tio_request)
+ * or making direct call to map_request().
+ */
+ tio->ti = ti;
+
+ /* Clone the request if underlying devices aren't blk-mq */
+ if (dm_table_get_type(map) == DM_TYPE_REQUEST_BASED) {
+ /* clone request is allocated at the end of the pdu */
+ tio->clone = (void *)blk_mq_rq_to_pdu(rq) + sizeof(struct dm_rq_target_io);
+ (void) clone_rq(rq, md, tio, GFP_ATOMIC);
+ queue_kthread_work(&md->kworker, &tio->work);
+ } else {
+ /* Direct call is fine since .queue_rq allows allocations */
+ if (map_request(tio, rq, md) == DM_MAPIO_REQUEUE) {
+ /* Undo dm_start_request() before requeuing */
+ rq_completed(md, rq_data_dir(rq), false);
+ return BLK_MQ_RQ_QUEUE_BUSY;
+ }
+ }
+
+ return BLK_MQ_RQ_QUEUE_OK;
+}
+
+static struct blk_mq_ops dm_mq_ops = {
+ .queue_rq = dm_mq_queue_rq,
+ .map_queue = blk_mq_map_queue,
+ .complete = dm_softirq_done,
+ .init_request = dm_mq_init_request,
+};
+
+static int dm_init_request_based_blk_mq_queue(struct mapped_device *md)
+{
+ unsigned md_type = dm_get_md_type(md);
+ struct request_queue *q;
+ int err;
+
+ memset(&md->tag_set, 0, sizeof(md->tag_set));
+ md->tag_set.ops = &dm_mq_ops;
+ md->tag_set.queue_depth = BLKDEV_MAX_RQ;
+ md->tag_set.numa_node = NUMA_NO_NODE;
+ md->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE;
+ md->tag_set.nr_hw_queues = 1;
+ if (md_type == DM_TYPE_REQUEST_BASED) {
+ /* make the memory for non-blk-mq clone part of the pdu */
+ md->tag_set.cmd_size = sizeof(struct dm_rq_target_io) + sizeof(struct request);
+ } else
+ md->tag_set.cmd_size = sizeof(struct dm_rq_target_io);
+ md->tag_set.driver_data = md;
+
+ err = blk_mq_alloc_tag_set(&md->tag_set);
+ if (err)
+ return err;
+
+ q = blk_mq_init_allocated_queue(&md->tag_set, md->queue);
+ if (IS_ERR(q)) {
+ err = PTR_ERR(q);
+ goto out_tag_set;
+ }
+ md->queue = q;
+ dm_init_md_queue(md);
+
+ /* backfill 'mq' sysfs registration normally done in blk_register_queue */
+ blk_mq_register_disk(md->disk);
+
+ if (md_type == DM_TYPE_REQUEST_BASED)
+ init_rq_based_worker_thread(md);
+
+ return 0;
+
+out_tag_set:
+ blk_mq_free_tag_set(&md->tag_set);
+ return err;
+}
+
+static unsigned filter_md_type(unsigned type, struct mapped_device *md)
+{
+ if (type == DM_TYPE_BIO_BASED)
+ return type;
+
+ return !md->use_blk_mq ? DM_TYPE_REQUEST_BASED : DM_TYPE_MQ_REQUEST_BASED;
+}
+
+/*
+ * Setup the DM device's queue based on md's type
+ */
+int dm_setup_md_queue(struct mapped_device *md)
+{
+ int r;
+ unsigned md_type = filter_md_type(dm_get_md_type(md), md);
+
+ switch (md_type) {
+ case DM_TYPE_REQUEST_BASED:
+ r = dm_init_request_based_queue(md);
+ if (r) {
+ DMWARN("Cannot initialize queue for request-based mapped device");
+ return r;
+ }
+ break;
+ case DM_TYPE_MQ_REQUEST_BASED:
+ r = dm_init_request_based_blk_mq_queue(md);
+ if (r) {
+ DMWARN("Cannot initialize queue for request-based blk-mq mapped device");
+ return r;
+ }
+ break;
+ case DM_TYPE_BIO_BASED:
+ dm_init_old_md_queue(md);
+ blk_queue_make_request(md->queue, dm_make_request);
+ blk_queue_merge_bvec(md->queue, dm_merge_bvec);
+ break;
+ }
+
+ return 0;
+}
+
+struct mapped_device *dm_get_md(dev_t dev)
+{
+ struct mapped_device *md;
+ unsigned minor = MINOR(dev);
+
+ if (MAJOR(dev) != _major || minor >= (1 << MINORBITS))
+ return NULL;
+
+ spin_lock(&_minor_lock);
+
+ md = idr_find(&_minor_idr, minor);
+ if (md) {
+ if ((md == MINOR_ALLOCED ||
+ (MINOR(disk_devt(dm_disk(md))) != minor) ||
+ dm_deleting_md(md) ||
+ test_bit(DMF_FREEING, &md->flags))) {
+ md = NULL;
+ goto out;
+ }
+ dm_get(md);
+ }
+
+out:
+ spin_unlock(&_minor_lock);
+
+ return md;
+}
+EXPORT_SYMBOL_GPL(dm_get_md);
+
+void *dm_get_mdptr(struct mapped_device *md)
+{
+ return md->interface_ptr;
+}
+
+void dm_set_mdptr(struct mapped_device *md, void *ptr)
+{
+ md->interface_ptr = ptr;
+}
+
+void dm_get(struct mapped_device *md)
+{
+ atomic_inc(&md->holders);
+ BUG_ON(test_bit(DMF_FREEING, &md->flags));
+}
+
+int dm_hold(struct mapped_device *md)
+{
+ spin_lock(&_minor_lock);
+ if (test_bit(DMF_FREEING, &md->flags)) {
+ spin_unlock(&_minor_lock);
+ return -EBUSY;
+ }
+ dm_get(md);
+ spin_unlock(&_minor_lock);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(dm_hold);
+
+const char *dm_device_name(struct mapped_device *md)
+{
+ return md->name;
+}
+EXPORT_SYMBOL_GPL(dm_device_name);
+
+static void __dm_destroy(struct mapped_device *md, bool wait)
+{
+ struct dm_table *map;
+ int srcu_idx;
+
+ might_sleep();
+
+ map = dm_get_live_table(md, &srcu_idx);
+
+ spin_lock(&_minor_lock);
+ idr_replace(&_minor_idr, MINOR_ALLOCED, MINOR(disk_devt(dm_disk(md))));
+ set_bit(DMF_FREEING, &md->flags);
+ spin_unlock(&_minor_lock);
+
+ if (dm_request_based(md) && md->kworker_task)
+ flush_kthread_worker(&md->kworker);
+
+ /*
+ * Take suspend_lock so that presuspend and postsuspend methods
+ * do not race with internal suspend.
+ */
+ mutex_lock(&md->suspend_lock);
+ if (!dm_suspended_md(md)) {
+ dm_table_presuspend_targets(map);
+ dm_table_postsuspend_targets(map);
+ }
+ mutex_unlock(&md->suspend_lock);
+
+ /* dm_put_live_table must be before msleep, otherwise deadlock is possible */
+ dm_put_live_table(md, srcu_idx);
+
+ /*
+ * Rare, but there may be I/O requests still going to complete,
+ * for example. Wait for all references to disappear.
+ * No one should increment the reference count of the mapped_device,
+ * after the mapped_device state becomes DMF_FREEING.
+ */
+ if (wait)
+ while (atomic_read(&md->holders))
+ msleep(1);
+ else if (atomic_read(&md->holders))
+ DMWARN("%s: Forcibly removing mapped_device still in use! (%d users)",
+ dm_device_name(md), atomic_read(&md->holders));
+
+ dm_sysfs_exit(md);
+ dm_table_destroy(__unbind(md));
+ free_dev(md);
+}
+
+void dm_destroy(struct mapped_device *md)
+{
+ __dm_destroy(md, true);
+}
+
+void dm_destroy_immediate(struct mapped_device *md)
+{
+ __dm_destroy(md, false);
+}
+
+void dm_put(struct mapped_device *md)
+{
+ atomic_dec(&md->holders);
+}
+EXPORT_SYMBOL_GPL(dm_put);
+
+static int dm_wait_for_completion(struct mapped_device *md, int interruptible)
+{
+ int r = 0;
+ DECLARE_WAITQUEUE(wait, current);
+
+ add_wait_queue(&md->wait, &wait);
+
+ while (1) {
+ set_current_state(interruptible);
+
+ if (!md_in_flight(md))
+ break;
+
+ if (interruptible == TASK_INTERRUPTIBLE &&
+ signal_pending(current)) {
+ r = -EINTR;
+ break;
+ }
+
+ io_schedule();
+ }
+ set_current_state(TASK_RUNNING);
+
+ remove_wait_queue(&md->wait, &wait);
+
+ return r;
+}
+
+/*
+ * Process the deferred bios
+ */
+static void dm_wq_work(struct work_struct *work)
+{
+ struct mapped_device *md = container_of(work, struct mapped_device,
+ work);
+ struct bio *c;
+ int srcu_idx;
+ struct dm_table *map;
+
+ map = dm_get_live_table(md, &srcu_idx);
+
+ while (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) {
+ spin_lock_irq(&md->deferred_lock);
+ c = bio_list_pop(&md->deferred);
+ spin_unlock_irq(&md->deferred_lock);
+
+ if (!c)
+ break;
+
+ if (dm_request_based(md))
+ generic_make_request(c);
+ else
+ __split_and_process_bio(md, map, c);
+ }
+
+ dm_put_live_table(md, srcu_idx);
+}
+
+static void dm_queue_flush(struct mapped_device *md)
+{
+ clear_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
+ smp_mb__after_atomic();
+ queue_work(md->wq, &md->work);
+}
+
+/*
+ * Swap in a new table, returning the old one for the caller to destroy.
+ */
+struct dm_table *dm_swap_table(struct mapped_device *md, struct dm_table *table)
+{
+ struct dm_table *live_map = NULL, *map = ERR_PTR(-EINVAL);
+ struct queue_limits limits;
+ int r;
+
+ mutex_lock(&md->suspend_lock);
+
+ /* device must be suspended */
+ if (!dm_suspended_md(md))
+ goto out;
+
+ /*
+ * If the new table has no data devices, retain the existing limits.
+ * This helps multipath with queue_if_no_path if all paths disappear,
+ * then new I/O is queued based on these limits, and then some paths
+ * reappear.
+ */
+ if (dm_table_has_no_data_devices(table)) {
+ live_map = dm_get_live_table_fast(md);
+ if (live_map)
+ limits = md->queue->limits;
+ dm_put_live_table_fast(md);
+ }
+
+ if (!live_map) {
+ r = dm_calculate_queue_limits(table, &limits);
+ if (r) {
+ map = ERR_PTR(r);
+ goto out;
+ }
+ }
+
+ map = __bind(md, table, &limits);
+
+out:
+ mutex_unlock(&md->suspend_lock);
+ return map;
+}
+
+/*
+ * Functions to lock and unlock any filesystem running on the
+ * device.
+ */
+static int lock_fs(struct mapped_device *md)
+{
+ int r;
+
+ WARN_ON(md->frozen_sb);
+
+ md->frozen_sb = freeze_bdev(md->bdev);
+ if (IS_ERR(md->frozen_sb)) {
+ r = PTR_ERR(md->frozen_sb);
+ md->frozen_sb = NULL;
+ return r;
+ }
+
+ set_bit(DMF_FROZEN, &md->flags);
+
+ return 0;
+}
+
+static void unlock_fs(struct mapped_device *md)
+{
+ if (!test_bit(DMF_FROZEN, &md->flags))
+ return;
+
+ thaw_bdev(md->bdev, md->frozen_sb);
+ md->frozen_sb = NULL;
+ clear_bit(DMF_FROZEN, &md->flags);
+}
+
+/*
+ * If __dm_suspend returns 0, the device is completely quiescent
+ * now. There is no request-processing activity. All new requests
+ * are being added to md->deferred list.
+ *
+ * Caller must hold md->suspend_lock
+ */
+static int __dm_suspend(struct mapped_device *md, struct dm_table *map,
+ unsigned suspend_flags, int interruptible)
+{
+ bool do_lockfs = suspend_flags & DM_SUSPEND_LOCKFS_FLAG;
+ bool noflush = suspend_flags & DM_SUSPEND_NOFLUSH_FLAG;
+ int r;
+
+ /*
+ * DMF_NOFLUSH_SUSPENDING must be set before presuspend.
+ * This flag is cleared before dm_suspend returns.
+ */
+ if (noflush)
+ set_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
+
+ /*
+ * This gets reverted if there's an error later and the targets
+ * provide the .presuspend_undo hook.
+ */
+ dm_table_presuspend_targets(map);
+
+ /*
+ * Flush I/O to the device.
+ * Any I/O submitted after lock_fs() may not be flushed.
+ * noflush takes precedence over do_lockfs.
+ * (lock_fs() flushes I/Os and waits for them to complete.)
+ */
+ if (!noflush && do_lockfs) {
+ r = lock_fs(md);
+ if (r) {
+ dm_table_presuspend_undo_targets(map);
+ return r;
+ }
+ }
+
+ /*
+ * Here we must make sure that no processes are submitting requests
+ * to target drivers i.e. no one may be executing
+ * __split_and_process_bio. This is called from dm_request and
+ * dm_wq_work.
+ *
+ * To get all processes out of __split_and_process_bio in dm_request,
+ * we take the write lock. To prevent any process from reentering
+ * __split_and_process_bio from dm_request and quiesce the thread
+ * (dm_wq_work), we set BMF_BLOCK_IO_FOR_SUSPEND and call
+ * flush_workqueue(md->wq).
+ */
+ set_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
+ if (map)
+ synchronize_srcu(&md->io_barrier);
+
+ /*
+ * Stop md->queue before flushing md->wq in case request-based
+ * dm defers requests to md->wq from md->queue.
+ */
+ if (dm_request_based(md)) {
+ stop_queue(md->queue);
+ if (md->kworker_task)
+ flush_kthread_worker(&md->kworker);
+ }
+
+ flush_workqueue(md->wq);
+
+ /*
+ * At this point no more requests are entering target request routines.
+ * We call dm_wait_for_completion to wait for all existing requests
+ * to finish.
+ */
+ r = dm_wait_for_completion(md, interruptible);
+
+ if (noflush)
+ clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
+ if (map)
+ synchronize_srcu(&md->io_barrier);
+
+ /* were we interrupted ? */
+ if (r < 0) {
+ dm_queue_flush(md);
+
+ if (dm_request_based(md))
+ start_queue(md->queue);
+
+ unlock_fs(md);
+ dm_table_presuspend_undo_targets(map);
+ /* pushback list is already flushed, so skip flush */
+ }
+
+ return r;
+}
+
+/*
+ * We need to be able to change a mapping table under a mounted
+ * filesystem. For example we might want to move some data in
+ * the background. Before the table can be swapped with
+ * dm_bind_table, dm_suspend must be called to flush any in
+ * flight bios and ensure that any further io gets deferred.
+ */
+/*
+ * Suspend mechanism in request-based dm.
+ *
+ * 1. Flush all I/Os by lock_fs() if needed.
+ * 2. Stop dispatching any I/O by stopping the request_queue.
+ * 3. Wait for all in-flight I/Os to be completed or requeued.
+ *
+ * To abort suspend, start the request_queue.
+ */
+int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
+{
+ struct dm_table *map = NULL;
+ int r = 0;
+
+retry:
+ mutex_lock_nested(&md->suspend_lock, SINGLE_DEPTH_NESTING);
+
+ if (dm_suspended_md(md)) {
+ r = -EINVAL;
+ goto out_unlock;
+ }
+
+ if (dm_suspended_internally_md(md)) {
+ /* already internally suspended, wait for internal resume */
+ mutex_unlock(&md->suspend_lock);
+ r = wait_on_bit(&md->flags, DMF_SUSPENDED_INTERNALLY, TASK_INTERRUPTIBLE);
+ if (r)
+ return r;
+ goto retry;
+ }
+
+ map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock));
+
+ r = __dm_suspend(md, map, suspend_flags, TASK_INTERRUPTIBLE);
+ if (r)
+ goto out_unlock;
+
+ set_bit(DMF_SUSPENDED, &md->flags);
+
+ dm_table_postsuspend_targets(map);
+
+out_unlock:
+ mutex_unlock(&md->suspend_lock);
+ return r;
+}
+
+static int __dm_resume(struct mapped_device *md, struct dm_table *map)
+{
+ if (map) {
+ int r = dm_table_resume_targets(map);
+ if (r)
+ return r;
+ }
+
+ dm_queue_flush(md);
+
+ /*
+ * Flushing deferred I/Os must be done after targets are resumed
+ * so that mapping of targets can work correctly.
+ * Request-based dm is queueing the deferred I/Os in its request_queue.
+ */
+ if (dm_request_based(md))
+ start_queue(md->queue);
+
+ unlock_fs(md);
+
+ return 0;
+}
+
+int dm_resume(struct mapped_device *md)
+{
+ int r = -EINVAL;
+ struct dm_table *map = NULL;
+
+retry:
+ mutex_lock_nested(&md->suspend_lock, SINGLE_DEPTH_NESTING);
+
+ if (!dm_suspended_md(md))
+ goto out;
+
+ if (dm_suspended_internally_md(md)) {
+ /* already internally suspended, wait for internal resume */
+ mutex_unlock(&md->suspend_lock);
+ r = wait_on_bit(&md->flags, DMF_SUSPENDED_INTERNALLY, TASK_INTERRUPTIBLE);
+ if (r)
+ return r;
+ goto retry;
+ }
+
+ map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock));
+ if (!map || !dm_table_get_size(map))
+ goto out;
+
+ r = __dm_resume(md, map);
+ if (r)
+ goto out;
+
+ clear_bit(DMF_SUSPENDED, &md->flags);
+
+ r = 0;
+out:
+ mutex_unlock(&md->suspend_lock);
+
+ return r;
+}
+
+/*
+ * Internal suspend/resume works like userspace-driven suspend. It waits
+ * until all bios finish and prevents issuing new bios to the target drivers.
+ * It may be used only from the kernel.
+ */
+
+static void __dm_internal_suspend(struct mapped_device *md, unsigned suspend_flags)
+{
+ struct dm_table *map = NULL;
+
+ if (md->internal_suspend_count++)
+ return; /* nested internal suspend */
+
+ if (dm_suspended_md(md)) {
+ set_bit(DMF_SUSPENDED_INTERNALLY, &md->flags);
+ return; /* nest suspend */
+ }
+
+ map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock));
+
+ /*
+ * Using TASK_UNINTERRUPTIBLE because only NOFLUSH internal suspend is
+ * supported. Properly supporting a TASK_INTERRUPTIBLE internal suspend
+ * would require changing .presuspend to return an error -- avoid this
+ * until there is a need for more elaborate variants of internal suspend.
+ */
+ (void) __dm_suspend(md, map, suspend_flags, TASK_UNINTERRUPTIBLE);
+
+ set_bit(DMF_SUSPENDED_INTERNALLY, &md->flags);
+
+ dm_table_postsuspend_targets(map);
+}
+
+static void __dm_internal_resume(struct mapped_device *md)
+{
+ BUG_ON(!md->internal_suspend_count);
+
+ if (--md->internal_suspend_count)
+ return; /* resume from nested internal suspend */
+
+ if (dm_suspended_md(md))
+ goto done; /* resume from nested suspend */
+
+ /*
+ * NOTE: existing callers don't need to call dm_table_resume_targets
+ * (which may fail -- so best to avoid it for now by passing NULL map)
+ */
+ (void) __dm_resume(md, NULL);
+
+done:
+ clear_bit(DMF_SUSPENDED_INTERNALLY, &md->flags);
+ smp_mb__after_atomic();
+ wake_up_bit(&md->flags, DMF_SUSPENDED_INTERNALLY);
+}
+
+void dm_internal_suspend_noflush(struct mapped_device *md)
+{
+ mutex_lock(&md->suspend_lock);
+ __dm_internal_suspend(md, DM_SUSPEND_NOFLUSH_FLAG);
+ mutex_unlock(&md->suspend_lock);
+}
+EXPORT_SYMBOL_GPL(dm_internal_suspend_noflush);
+
+void dm_internal_resume(struct mapped_device *md)
+{
+ mutex_lock(&md->suspend_lock);
+ __dm_internal_resume(md);
+ mutex_unlock(&md->suspend_lock);
+}
+EXPORT_SYMBOL_GPL(dm_internal_resume);
+
+/*
+ * Fast variants of internal suspend/resume hold md->suspend_lock,
+ * which prevents interaction with userspace-driven suspend.
+ */
+
+void dm_internal_suspend_fast(struct mapped_device *md)
+{
+ mutex_lock(&md->suspend_lock);
+ if (dm_suspended_md(md) || dm_suspended_internally_md(md))
+ return;
+
+ set_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
+ synchronize_srcu(&md->io_barrier);
+ flush_workqueue(md->wq);
+ dm_wait_for_completion(md, TASK_UNINTERRUPTIBLE);
+}
+EXPORT_SYMBOL_GPL(dm_internal_suspend_fast);
+
+void dm_internal_resume_fast(struct mapped_device *md)
+{
+ if (dm_suspended_md(md) || dm_suspended_internally_md(md))
+ goto done;
+
+ dm_queue_flush(md);
+
+done:
+ mutex_unlock(&md->suspend_lock);
+}
+EXPORT_SYMBOL_GPL(dm_internal_resume_fast);
+
+/*-----------------------------------------------------------------
+ * Event notification.
+ *---------------------------------------------------------------*/
+int dm_kobject_uevent(struct mapped_device *md, enum kobject_action action,
+ unsigned cookie)
+{
+ char udev_cookie[DM_COOKIE_LENGTH];
+ char *envp[] = { udev_cookie, NULL };
+
+ if (!cookie)
+ return kobject_uevent(&disk_to_dev(md->disk)->kobj, action);
+ else {
+ snprintf(udev_cookie, DM_COOKIE_LENGTH, "%s=%u",
+ DM_COOKIE_ENV_VAR_NAME, cookie);
+ return kobject_uevent_env(&disk_to_dev(md->disk)->kobj,
+ action, envp);
+ }
+}
+
+uint32_t dm_next_uevent_seq(struct mapped_device *md)
+{
+ return atomic_add_return(1, &md->uevent_seq);
+}
+
+uint32_t dm_get_event_nr(struct mapped_device *md)
+{
+ return atomic_read(&md->event_nr);
+}
+
+int dm_wait_event(struct mapped_device *md, int event_nr)
+{
+ return wait_event_interruptible(md->eventq,
+ (event_nr != atomic_read(&md->event_nr)));
+}
+
+void dm_uevent_add(struct mapped_device *md, struct list_head *elist)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&md->uevent_lock, flags);
+ list_add(elist, &md->uevent_list);
+ spin_unlock_irqrestore(&md->uevent_lock, flags);
+}
+
+/*
+ * The gendisk is only valid as long as you have a reference
+ * count on 'md'.
+ */
+struct gendisk *dm_disk(struct mapped_device *md)
+{
+ return md->disk;
+}
+EXPORT_SYMBOL_GPL(dm_disk);
+
+struct kobject *dm_kobject(struct mapped_device *md)
+{
+ return &md->kobj_holder.kobj;
+}
+
+struct mapped_device *dm_get_from_kobject(struct kobject *kobj)
+{
+ struct mapped_device *md;
+
+ md = container_of(kobj, struct mapped_device, kobj_holder.kobj);
+
+ if (test_bit(DMF_FREEING, &md->flags) ||
+ dm_deleting_md(md))
+ return NULL;
+
+ dm_get(md);
+ return md;
+}
+
+int dm_suspended_md(struct mapped_device *md)
+{
+ return test_bit(DMF_SUSPENDED, &md->flags);
+}
+
+int dm_suspended_internally_md(struct mapped_device *md)
+{
+ return test_bit(DMF_SUSPENDED_INTERNALLY, &md->flags);
+}
+
+int dm_test_deferred_remove_flag(struct mapped_device *md)
+{
+ return test_bit(DMF_DEFERRED_REMOVE, &md->flags);
+}
+
+int dm_suspended(struct dm_target *ti)
+{
+ return dm_suspended_md(dm_table_get_md(ti->table));
+}
+EXPORT_SYMBOL_GPL(dm_suspended);
+
+int dm_noflush_suspending(struct dm_target *ti)
+{
+ return __noflush_suspending(dm_table_get_md(ti->table));
+}
+EXPORT_SYMBOL_GPL(dm_noflush_suspending);
+
+struct dm_md_mempools *dm_alloc_md_mempools(struct mapped_device *md, unsigned type,
+ unsigned integrity, unsigned per_bio_data_size)
+{
+ struct dm_md_mempools *pools = kzalloc(sizeof(*pools), GFP_KERNEL);
+ struct kmem_cache *cachep = NULL;
+ unsigned int pool_size = 0;
+ unsigned int front_pad;
+
+ if (!pools)
+ return NULL;
+
+ type = filter_md_type(type, md);
+
+ switch (type) {
+ case DM_TYPE_BIO_BASED:
+ cachep = _io_cache;
+ pool_size = dm_get_reserved_bio_based_ios();
+ front_pad = roundup(per_bio_data_size, __alignof__(struct dm_target_io)) + offsetof(struct dm_target_io, clone);
+ break;
+ case DM_TYPE_REQUEST_BASED:
+ cachep = _rq_tio_cache;
+ pool_size = dm_get_reserved_rq_based_ios();
+ pools->rq_pool = mempool_create_slab_pool(pool_size, _rq_cache);
+ if (!pools->rq_pool)
+ goto out;
+ /* fall through to setup remaining rq-based pools */
+ case DM_TYPE_MQ_REQUEST_BASED:
+ if (!pool_size)
+ pool_size = dm_get_reserved_rq_based_ios();
+ front_pad = offsetof(struct dm_rq_clone_bio_info, clone);
+ /* per_bio_data_size is not used. See __bind_mempools(). */
+ WARN_ON(per_bio_data_size != 0);
+ break;
+ default:
+ BUG();
+ }
+
+ if (cachep) {
+ pools->io_pool = mempool_create_slab_pool(pool_size, cachep);
+ if (!pools->io_pool)
+ goto out;
+ }
+
+ pools->bs = bioset_create_nobvec(pool_size, front_pad);
+ if (!pools->bs)
+ goto out;
+
+ if (integrity && bioset_integrity_create(pools->bs, pool_size))
+ goto out;
+
+ return pools;
+
+out:
+ dm_free_md_mempools(pools);
+
+ return NULL;
+}
+
+void dm_free_md_mempools(struct dm_md_mempools *pools)
+{
+ if (!pools)
+ return;
+
+ if (pools->io_pool)
+ mempool_destroy(pools->io_pool);
+
+ if (pools->rq_pool)
+ mempool_destroy(pools->rq_pool);
+
+ if (pools->bs)
+ bioset_free(pools->bs);
+
+ kfree(pools);
+}
+
+static const struct block_device_operations dm_blk_dops = {
+ .open = dm_blk_open,
+ .release = dm_blk_close,
+ .ioctl = dm_blk_ioctl,
+ .getgeo = dm_blk_getgeo,
+ .owner = THIS_MODULE
+};
+
+/*
+ * module hooks
+ */
+module_init(dm_init);
+module_exit(dm_exit);
+
+module_param(major, uint, 0);
+MODULE_PARM_DESC(major, "The major number of the device mapper");
+
+module_param(reserved_bio_based_ios, uint, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(reserved_bio_based_ios, "Reserved IOs in bio-based mempools");
+
+module_param(reserved_rq_based_ios, uint, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(reserved_rq_based_ios, "Reserved IOs in request-based mempools");
+
+module_param(use_blk_mq, bool, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(use_blk_mq, "Use block multiqueue for request-based DM devices");
+
+MODULE_DESCRIPTION(DM_NAME " driver");
+MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
+MODULE_LICENSE("GPL");
Code Review / kvmfornfv.git / blobdiff