dm thin: prepare to separate bio_prison code

The bio prison code will be useful to share with future DM targets.

Prepare to move this code into a separate module, adding a dm prefix
to structures and functions that will be exported.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

1 files changed, 131 insertions, 90 deletions

diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index df20a115136f..22a22a701e16 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -58,7 +58,7 @@
  * i) plug io further to this physical block. (see bio_prison code).
  *
  * ii) quiesce any read io to that shared data block.  Obviously
- * including all devices that share this block.  (see deferred_set code)
+ * including all devices that share this block.  (see dm_deferred_set code)
  *
  * iii) copy the data block to a newly allocate block.  This step can be
  * missed out if the io covers the block. (schedule_copy).
@@ -104,9 +104,9 @@
  * by a key, multiple bios can be in the same cell.  When the cell is
  * subsequently unlocked the bios become available.
  */
-struct bio_prison;
+struct dm_bio_prison;
 
-struct cell_key {
+struct dm_cell_key {
 	int virtual;
 	dm_thin_id dev;
 	dm_block_t block;
@@ -114,13 +114,13 @@ struct cell_key {
 
 struct dm_bio_prison_cell {
 	struct hlist_node list;
-	struct bio_prison *prison;
-	struct cell_key key;
+	struct dm_bio_prison *prison;
+	struct dm_cell_key key;
 	struct bio *holder;
 	struct bio_list bios;
 };
 
-struct bio_prison {
+struct dm_bio_prison {
 	spinlock_t lock;
 	mempool_t *cell_pool;
 
@@ -148,13 +148,13 @@ static struct kmem_cache *_cell_cache;
  * @nr_cells should be the number of cells you want in use _concurrently_.
  * Don't confuse it with the number of distinct keys.
  */
-static struct bio_prison *prison_create(unsigned nr_cells)
+static struct dm_bio_prison *dm_bio_prison_create(unsigned nr_cells)
 {
 	unsigned i;
 	uint32_t nr_buckets = calc_nr_buckets(nr_cells);
-	size_t len = sizeof(struct bio_prison) +
+	size_t len = sizeof(struct dm_bio_prison) +
 		(sizeof(struct hlist_head) * nr_buckets);
-	struct bio_prison *prison = kmalloc(len, GFP_KERNEL);
+	struct dm_bio_prison *prison = kmalloc(len, GFP_KERNEL);
 
 	if (!prison)
 		return NULL;
@@ -175,13 +175,13 @@ static struct bio_prison *prison_create(unsigned nr_cells)
 	return prison;
 }
 
-static void prison_destroy(struct bio_prison *prison)
+static void dm_bio_prison_destroy(struct dm_bio_prison *prison)
 {
 	mempool_destroy(prison->cell_pool);
 	kfree(prison);
 }
 
-static uint32_t hash_key(struct bio_prison *prison, struct cell_key *key)
+static uint32_t hash_key(struct dm_bio_prison *prison, struct dm_cell_key *key)
 {
 	const unsigned long BIG_PRIME = 4294967291UL;
 	uint64_t hash = key->block * BIG_PRIME;
@@ -189,7 +189,7 @@ static uint32_t hash_key(struct bio_prison *prison, struct cell_key *key)
 	return (uint32_t) (hash & prison->hash_mask);
 }
 
-static int keys_equal(struct cell_key *lhs, struct cell_key *rhs)
+static int keys_equal(struct dm_cell_key *lhs, struct dm_cell_key *rhs)
 {
 	       return (lhs->virtual == rhs->virtual) &&
 		       (lhs->dev == rhs->dev) &&
@@ -197,7 +197,7 @@ static int keys_equal(struct cell_key *lhs, struct cell_key *rhs)
 }
 
 static struct dm_bio_prison_cell *__search_bucket(struct hlist_head *bucket,
-						  struct cell_key *key)
+						  struct dm_cell_key *key)
 {
 	struct dm_bio_prison_cell *cell;
 	struct hlist_node *tmp;
@@ -215,8 +215,8 @@ static struct dm_bio_prison_cell *__search_bucket(struct hlist_head *bucket,
  *
  * Returns 1 if the cell was already held, 0 if @inmate is the new holder.
  */
-static int bio_detain(struct bio_prison *prison, struct cell_key *key,
-		      struct bio *inmate, struct dm_bio_prison_cell **ref)
+static int dm_bio_detain(struct dm_bio_prison *prison, struct dm_cell_key *key,
+			 struct bio *inmate, struct dm_bio_prison_cell **ref)
 {
 	int r = 1;
 	unsigned long flags;
@@ -277,7 +277,7 @@ out:
  */
 static void __cell_release(struct dm_bio_prison_cell *cell, struct bio_list *inmates)
 {
-	struct bio_prison *prison = cell->prison;
+	struct dm_bio_prison *prison = cell->prison;
 
 	hlist_del(&cell->list);
 
@@ -289,10 +289,10 @@ static void __cell_release(struct dm_bio_prison_cell *cell, struct bio_list *inm
 	mempool_free(cell, prison->cell_pool);
 }
 
-static void cell_release(struct dm_bio_prison_cell *cell, struct bio_list *bios)
+static void dm_cell_release(struct dm_bio_prison_cell *cell, struct bio_list *bios)
 {
 	unsigned long flags;
-	struct bio_prison *prison = cell->prison;
+	struct dm_bio_prison *prison = cell->prison;
 
 	spin_lock_irqsave(&prison->lock, flags);
 	__cell_release(cell, bios);
@@ -313,10 +313,10 @@ static void __cell_release_singleton(struct dm_bio_prison_cell *cell, struct bio
 	__cell_release(cell, NULL);
 }
 
-static void cell_release_singleton(struct dm_bio_prison_cell *cell, struct bio *bio)
+static void dm_cell_release_singleton(struct dm_bio_prison_cell *cell, struct bio *bio)
 {
 	unsigned long flags;
-	struct bio_prison *prison = cell->prison;
+	struct dm_bio_prison *prison = cell->prison;
 
 	spin_lock_irqsave(&prison->lock, flags);
 	__cell_release_singleton(cell, bio);
@@ -329,7 +329,7 @@ static void cell_release_singleton(struct dm_bio_prison_cell *cell, struct bio *
 static void __cell_release_no_holder(struct dm_bio_prison_cell *cell,
 				     struct bio_list *inmates)
 {
-	struct bio_prison *prison = cell->prison;
+	struct dm_bio_prison *prison = cell->prison;
 
 	hlist_del(&cell->list);
 	bio_list_merge(inmates, &cell->bios);
@@ -337,20 +337,20 @@ static void __cell_release_no_holder(struct dm_bio_prison_cell *cell,
 	mempool_free(cell, prison->cell_pool);
 }
 
-static void cell_release_no_holder(struct dm_bio_prison_cell *cell,
-				   struct bio_list *inmates)
+static void dm_cell_release_no_holder(struct dm_bio_prison_cell *cell,
+				      struct bio_list *inmates)
 {
 	unsigned long flags;
-	struct bio_prison *prison = cell->prison;
+	struct dm_bio_prison *prison = cell->prison;
 
 	spin_lock_irqsave(&prison->lock, flags);
 	__cell_release_no_holder(cell, inmates);
 	spin_unlock_irqrestore(&prison->lock, flags);
 }
 
-static void cell_error(struct dm_bio_prison_cell *cell)
+static void dm_cell_error(struct dm_bio_prison_cell *cell)
 {
-	struct bio_prison *prison = cell->prison;
+	struct dm_bio_prison *prison = cell->prison;
 	struct bio_list bios;
 	struct bio *bio;
 	unsigned long flags;
@@ -374,23 +374,28 @@ static void cell_error(struct dm_bio_prison_cell *cell)
  * new mapping could free the old block that the read bios are mapped to.
  */
 
-struct deferred_set;
-struct deferred_entry {
-	struct deferred_set *ds;
+struct dm_deferred_set;
+struct dm_deferred_entry {
+	struct dm_deferred_set *ds;
 	unsigned count;
 	struct list_head work_items;
 };
 
-struct deferred_set {
+struct dm_deferred_set {
 	spinlock_t lock;
 	unsigned current_entry;
 	unsigned sweeper;
-	struct deferred_entry entries[DEFERRED_SET_SIZE];
+	struct dm_deferred_entry entries[DEFERRED_SET_SIZE];
 };
 
-static void ds_init(struct deferred_set *ds)
+static struct dm_deferred_set *dm_deferred_set_create(void)
 {
 	int i;
+	struct dm_deferred_set *ds;
+
+	ds = kmalloc(sizeof(*ds), GFP_KERNEL);
+	if (!ds)
+		return NULL;
 
 	spin_lock_init(&ds->lock);
 	ds->current_entry = 0;
@@ -400,12 +405,19 @@ static void ds_init(struct deferred_set *ds)
 		ds->entries[i].count = 0;
 		INIT_LIST_HEAD(&ds->entries[i].work_items);
 	}
+
+	return ds;
 }
 
-static struct deferred_entry *ds_inc(struct deferred_set *ds)
+static void dm_deferred_set_destroy(struct dm_deferred_set *ds)
+{
+	kfree(ds);
+}
+
+static struct dm_deferred_entry *dm_deferred_entry_inc(struct dm_deferred_set *ds)
 {
 	unsigned long flags;
-	struct deferred_entry *entry;
+	struct dm_deferred_entry *entry;
 
 	spin_lock_irqsave(&ds->lock, flags);
 	entry = ds->entries + ds->current_entry;
@@ -420,7 +432,7 @@ static unsigned ds_next(unsigned index)
 	return (index + 1) % DEFERRED_SET_SIZE;
 }
 
-static void __sweep(struct deferred_set *ds, struct list_head *head)
+static void __sweep(struct dm_deferred_set *ds, struct list_head *head)
 {
 	while ((ds->sweeper != ds->current_entry) &&
 	       !ds->entries[ds->sweeper].count) {
@@ -432,7 +444,7 @@ static void __sweep(struct deferred_set *ds, struct list_head *head)
 		list_splice_init(&ds->entries[ds->sweeper].work_items, head);
 }
 
-static void ds_dec(struct deferred_entry *entry, struct list_head *head)
+static void dm_deferred_entry_dec(struct dm_deferred_entry *entry, struct list_head *head)
 {
 	unsigned long flags;
 
@@ -446,7 +458,7 @@ static void ds_dec(struct deferred_entry *entry, struct list_head *head)
 /*
  * Returns 1 if deferred or 0 if no pending items to delay job.
  */
-static int ds_add_work(struct deferred_set *ds, struct list_head *work)
+static int dm_deferred_set_add_work(struct dm_deferred_set *ds, struct list_head *work)
 {
 	int r = 1;
 	unsigned long flags;
@@ -467,13 +479,28 @@ static int ds_add_work(struct deferred_set *ds, struct list_head *work)
 	return r;
 }
 
+static int __init dm_bio_prison_init(void)
+{
+	_cell_cache = KMEM_CACHE(dm_bio_prison_cell, 0);
+	if (!_cell_cache)
+		return -ENOMEM;
+
+	return 0;
+}
+
+static void __exit dm_bio_prison_exit(void)
+{
+	kmem_cache_destroy(_cell_cache);
+	_cell_cache = NULL;
+}
+
 /*----------------------------------------------------------------*/
 
 /*
  * Key building.
  */
 static void build_data_key(struct dm_thin_device *td,
-			   dm_block_t b, struct cell_key *key)
+			   dm_block_t b, struct dm_cell_key *key)
 {
 	key->virtual = 0;
 	key->dev = dm_thin_dev_id(td);
@@ -481,7 +508,7 @@ static void build_data_key(struct dm_thin_device *td,
 }
 
 static void build_virtual_key(struct dm_thin_device *td, dm_block_t b,
-			      struct cell_key *key)
+			      struct dm_cell_key *key)
 {
 	key->virtual = 1;
 	key->dev = dm_thin_dev_id(td);
@@ -534,7 +561,7 @@ struct pool {
 	unsigned low_water_triggered:1;	/* A dm event has been sent */
 	unsigned no_free_space:1;	/* A -ENOSPC warning has been issued */
 
-	struct bio_prison *prison;
+	struct dm_bio_prison *prison;
 	struct dm_kcopyd_client *copier;
 
 	struct workqueue_struct *wq;
@@ -552,8 +579,8 @@ struct pool {
 
 	struct bio_list retry_on_resume_list;
 
-	struct deferred_set shared_read_ds;
-	struct deferred_set all_io_ds;
+	struct dm_deferred_set *shared_read_ds;
+	struct dm_deferred_set *all_io_ds;
 
 	struct dm_thin_new_mapping *next_mapping;
 	mempool_t *mapping_pool;
@@ -660,8 +687,8 @@ static struct pool *__pool_table_lookup_metadata_dev(struct block_device *md_dev
 
 struct dm_thin_endio_hook {
 	struct thin_c *tc;
-	struct deferred_entry *shared_read_entry;
-	struct deferred_entry *all_io_entry;
+	struct dm_deferred_entry *shared_read_entry;
+	struct dm_deferred_entry *all_io_entry;
 	struct dm_thin_new_mapping *overwrite_mapping;
 };
 
@@ -877,7 +904,7 @@ static void cell_defer(struct thin_c *tc, struct dm_bio_prison_cell *cell,
 	unsigned long flags;
 
 	spin_lock_irqsave(&pool->lock, flags);
-	cell_release(cell, &pool->deferred_bios);
+	dm_cell_release(cell, &pool->deferred_bios);
 	spin_unlock_irqrestore(&tc->pool->lock, flags);
 
 	wake_worker(pool);
@@ -896,7 +923,7 @@ static void cell_defer_except(struct thin_c *tc, struct dm_bio_prison_cell *cell
 	bio_list_init(&bios);
 
 	spin_lock_irqsave(&pool->lock, flags);
-	cell_release_no_holder(cell, &pool->deferred_bios);
+	dm_cell_release_no_holder(cell, &pool->deferred_bios);
 	spin_unlock_irqrestore(&pool->lock, flags);
 
 	wake_worker(pool);
@@ -906,7 +933,7 @@ static void process_prepared_mapping_fail(struct dm_thin_new_mapping *m)
 {
 	if (m->bio)
 		m->bio->bi_end_io = m->saved_bi_end_io;
-	cell_error(m->cell);
+	dm_cell_error(m->cell);
 	list_del(&m->list);
 	mempool_free(m, m->tc->pool->mapping_pool);
 }
@@ -921,7 +948,7 @@ static void process_prepared_mapping(struct dm_thin_new_mapping *m)
 		bio->bi_end_io = m->saved_bi_end_io;
 
 	if (m->err) {
-		cell_error(m->cell);
+		dm_cell_error(m->cell);
 		goto out;
 	}
 
@@ -933,7 +960,7 @@ static void process_prepared_mapping(struct dm_thin_new_mapping *m)
 	r = dm_thin_insert_block(tc->td, m->virt_block, m->data_block);
 	if (r) {
 		DMERR("dm_thin_insert_block() failed");
-		cell_error(m->cell);
+		dm_cell_error(m->cell);
 		goto out;
 	}
 
@@ -1067,7 +1094,7 @@ static void schedule_copy(struct thin_c *tc, dm_block_t virt_block,
 	m->err = 0;
 	m->bio = NULL;
 
-	if (!ds_add_work(&pool->shared_read_ds, &m->list))
+	if (!dm_deferred_set_add_work(pool->shared_read_ds, &m->list))
 		m->quiesced = 1;
 
 	/*
@@ -1099,7 +1126,7 @@ static void schedule_copy(struct thin_c *tc, dm_block_t virt_block,
 		if (r < 0) {
 			mempool_free(m, pool->mapping_pool);
 			DMERR("dm_kcopyd_copy() failed");
-			cell_error(cell);
+			dm_cell_error(cell);
 		}
 	}
 }
@@ -1164,7 +1191,7 @@ static void schedule_zero(struct thin_c *tc, dm_block_t virt_block,
 		if (r < 0) {
 			mempool_free(m, pool->mapping_pool);
 			DMERR("dm_kcopyd_zero() failed");
-			cell_error(cell);
+			dm_cell_error(cell);
 		}
 	}
 }
@@ -1276,7 +1303,7 @@ static void no_space(struct dm_bio_prison_cell *cell)
 	struct bio_list bios;
 
 	bio_list_init(&bios);
-	cell_release(cell, &bios);
+	dm_cell_release(cell, &bios);
 
 	while ((bio = bio_list_pop(&bios)))
 		retry_on_resume(bio);
@@ -1288,13 +1315,13 @@ static void process_discard(struct thin_c *tc, struct bio *bio)
 	unsigned long flags;
 	struct pool *pool = tc->pool;
 	struct dm_bio_prison_cell *cell, *cell2;
-	struct cell_key key, key2;
+	struct dm_cell_key key, key2;
 	dm_block_t block = get_bio_block(tc, bio);
 	struct dm_thin_lookup_result lookup_result;
 	struct dm_thin_new_mapping *m;
 
 	build_virtual_key(tc->td, block, &key);
-	if (bio_detain(tc->pool->prison, &key, bio, &cell))
+	if (dm_bio_detain(tc->pool->prison, &key, bio, &cell))
 		return;
 
 	r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
@@ -1306,8 +1333,8 @@ static void process_discard(struct thin_c *tc, struct bio *bio)
 		 * on this block.
 		 */
 		build_data_key(tc->td, lookup_result.block, &key2);
-		if (bio_detain(tc->pool->prison, &key2, bio, &cell2)) {
-			cell_release_singleton(cell, bio);
+		if (dm_bio_detain(tc->pool->prison, &key2, bio, &cell2)) {
+			dm_cell_release_singleton(cell, bio);
 			break;
 		}
 
@@ -1326,7 +1353,7 @@ static void process_discard(struct thin_c *tc, struct bio *bio)
 			m->err = 0;
 			m->bio = bio;
 
-			if (!ds_add_work(&pool->all_io_ds, &m->list)) {
+			if (!dm_deferred_set_add_work(pool->all_io_ds, &m->list)) {
 				spin_lock_irqsave(&pool->lock, flags);
 				list_add(&m->list, &pool->prepared_discards);
 				spin_unlock_irqrestore(&pool->lock, flags);
@@ -1338,8 +1365,8 @@ static void process_discard(struct thin_c *tc, struct bio *bio)
 			 * a block boundary.  So we submit the discard of a
 			 * partial block appropriately.
 			 */
-			cell_release_singleton(cell, bio);
-			cell_release_singleton(cell2, bio);
+			dm_cell_release_singleton(cell, bio);
+			dm_cell_release_singleton(cell2, bio);
 			if ((!lookup_result.shared) && pool->pf.discard_passdown)
 				remap_and_issue(tc, bio, lookup_result.block);
 			else
@@ -1351,20 +1378,20 @@ static void process_discard(struct thin_c *tc, struct bio *bio)
 		/*
 		 * It isn't provisioned, just forget it.
 		 */
-		cell_release_singleton(cell, bio);
+		dm_cell_release_singleton(cell, bio);
 		bio_endio(bio, 0);
 		break;
 
 	default:
 		DMERR("discard: find block unexpectedly returned %d", r);
-		cell_release_singleton(cell, bio);
+		dm_cell_release_singleton(cell, bio);
 		bio_io_error(bio);
 		break;
 	}
 }
 
 static void break_sharing(struct thin_c *tc, struct bio *bio, dm_block_t block,
-			  struct cell_key *key,
+			  struct dm_cell_key *key,
 			  struct dm_thin_lookup_result *lookup_result,
 			  struct dm_bio_prison_cell *cell)
 {
@@ -1384,7 +1411,7 @@ static void break_sharing(struct thin_c *tc, struct bio *bio, dm_block_t block,
 
 	default:
 		DMERR("%s: alloc_data_block() failed, error = %d", __func__, r);
-		cell_error(cell);
+		dm_cell_error(cell);
 		break;
 	}
 }
@@ -1395,14 +1422,14 @@ static void process_shared_bio(struct thin_c *tc, struct bio *bio,
 {
 	struct dm_bio_prison_cell *cell;
 	struct pool *pool = tc->pool;
-	struct cell_key key;
+	struct dm_cell_key key;
 
 	/*
 	 * If cell is already occupied, then sharing is already in the process
 	 * of being broken so we have nothing further to do here.
 	 */
 	build_data_key(tc->td, lookup_result->block, &key);
-	if (bio_detain(pool->prison, &key, bio, &cell))
+	if (dm_bio_detain(pool->prison, &key, bio, &cell))
 		return;
 
 	if (bio_data_dir(bio) == WRITE && bio->bi_size)
@@ -1410,9 +1437,9 @@ static void process_shared_bio(struct thin_c *tc, struct bio *bio,
 	else {
 		struct dm_thin_endio_hook *h = dm_get_mapinfo(bio)->ptr;
 
-		h->shared_read_entry = ds_inc(&pool->shared_read_ds);
+		h->shared_read_entry = dm_deferred_entry_inc(pool->shared_read_ds);
 
-		cell_release_singleton(cell, bio);
+		dm_cell_release_singleton(cell, bio);
 		remap_and_issue(tc, bio, lookup_result->block);
 	}
 }
@@ -1427,7 +1454,7 @@ static void provision_block(struct thin_c *tc, struct bio *bio, dm_block_t block
 	 * Remap empty bios (flushes) immediately, without provisioning.
 	 */
 	if (!bio->bi_size) {
-		cell_release_singleton(cell, bio);
+		dm_cell_release_singleton(cell, bio);
 		remap_and_issue(tc, bio, 0);
 		return;
 	}
@@ -1437,7 +1464,7 @@ static void provision_block(struct thin_c *tc, struct bio *bio, dm_block_t block
 	 */
 	if (bio_data_dir(bio) == READ) {
 		zero_fill_bio(bio);
-		cell_release_singleton(cell, bio);
+		dm_cell_release_singleton(cell, bio);
 		bio_endio(bio, 0);
 		return;
 	}
@@ -1458,7 +1485,7 @@ static void provision_block(struct thin_c *tc, struct bio *bio, dm_block_t block
 	default:
 		DMERR("%s: alloc_data_block() failed, error = %d", __func__, r);
 		set_pool_mode(tc->pool, PM_READ_ONLY);
-		cell_error(cell);
+		dm_cell_error(cell);
 		break;
 	}
 }
@@ -1468,7 +1495,7 @@ static void process_bio(struct thin_c *tc, struct bio *bio)
 	int r;
 	dm_block_t block = get_bio_block(tc, bio);
 	struct dm_bio_prison_cell *cell;
-	struct cell_key key;
+	struct dm_cell_key key;
 	struct dm_thin_lookup_result lookup_result;
 
 	/*
@@ -1476,7 +1503,7 @@ static void process_bio(struct thin_c *tc, struct bio *bio)
 	 * being provisioned so we have nothing further to do here.
 	 */
 	build_virtual_key(tc->td, block, &key);
-	if (bio_detain(tc->pool->prison, &key, bio, &cell))
+	if (dm_bio_detain(tc->pool->prison, &key, bio, &cell))
 		return;
 
 	r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
@@ -1491,7 +1518,7 @@ static void process_bio(struct thin_c *tc, struct bio *bio)
 		 * TODO: this will probably have to change when discard goes
 		 * back in.
 		 */
-		cell_release_singleton(cell, bio);
+		dm_cell_release_singleton(cell, bio);
 
 		if (lookup_result.shared)
 			process_shared_bio(tc, bio, block, &lookup_result);
@@ -1501,7 +1528,7 @@ static void process_bio(struct thin_c *tc, struct bio *bio)
 
 	case -ENODATA:
 		if (bio_data_dir(bio) == READ && tc->origin_dev) {
-			cell_release_singleton(cell, bio);
+			dm_cell_release_singleton(cell, bio);
 			remap_to_origin_and_issue(tc, bio);
 		} else
 			provision_block(tc, bio, block, cell);
@@ -1509,7 +1536,7 @@ static void process_bio(struct thin_c *tc, struct bio *bio)
 
 	default:
 		DMERR("dm_thin_find_block() failed, error = %d", r);
-		cell_release_singleton(cell, bio);
+		dm_cell_release_singleton(cell, bio);
 		bio_io_error(bio);
 		break;
 	}
@@ -1718,7 +1745,7 @@ static struct dm_thin_endio_hook *thin_hook_bio(struct thin_c *tc, struct bio *b
 
 	h->tc = tc;
 	h->shared_read_entry = NULL;
-	h->all_io_entry = bio->bi_rw & REQ_DISCARD ? NULL : ds_inc(&pool->all_io_ds);
+	h->all_io_entry = bio->bi_rw & REQ_DISCARD ? NULL : dm_deferred_entry_inc(pool->all_io_ds);
 	h->overwrite_mapping = NULL;
 
 	return h;
@@ -1928,7 +1955,7 @@ static void __pool_destroy(struct pool *pool)
 	if (dm_pool_metadata_close(pool->pmd) < 0)
 		DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
 
-	prison_destroy(pool->prison);
+	dm_bio_prison_destroy(pool->prison);
 	dm_kcopyd_client_destroy(pool->copier);
 
 	if (pool->wq)
@@ -1938,6 +1965,8 @@ static void __pool_destroy(struct pool *pool)
 		mempool_free(pool->next_mapping, pool->mapping_pool);
 	mempool_destroy(pool->mapping_pool);
 	mempool_destroy(pool->endio_hook_pool);
+	dm_deferred_set_destroy(pool->shared_read_ds);
+	dm_deferred_set_destroy(pool->all_io_ds);
 	kfree(pool);
 }
 
@@ -1976,7 +2005,7 @@ static struct pool *pool_create(struct mapped_device *pool_md,
 		pool->sectors_per_block_shift = __ffs(block_size);
 	pool->low_water_blocks = 0;
 	pool_features_init(&pool->pf);
-	pool->prison = prison_create(PRISON_CELLS);
+	pool->prison = dm_bio_prison_create(PRISON_CELLS);
 	if (!pool->prison) {
 		*error = "Error creating pool's bio prison";
 		err_p = ERR_PTR(-ENOMEM);
@@ -2012,8 +2041,20 @@ static struct pool *pool_create(struct mapped_device *pool_md,
 	pool->low_water_triggered = 0;
 	pool->no_free_space = 0;
 	bio_list_init(&pool->retry_on_resume_list);
-	ds_init(&pool->shared_read_ds);
-	ds_init(&pool->all_io_ds);
+
+	pool->shared_read_ds = dm_deferred_set_create();
+	if (!pool->shared_read_ds) {
+		*error = "Error creating pool's shared read deferred set";
+		err_p = ERR_PTR(-ENOMEM);
+		goto bad_shared_read_ds;
+	}
+
+	pool->all_io_ds = dm_deferred_set_create();
+	if (!pool->all_io_ds) {
+		*error = "Error creating pool's all io deferred set";
+		err_p = ERR_PTR(-ENOMEM);
+		goto bad_all_io_ds;
+	}
 
 	pool->next_mapping = NULL;
 	pool->mapping_pool = mempool_create_slab_pool(MAPPING_POOL_SIZE,
@@ -2042,11 +2083,15 @@ static struct pool *pool_create(struct mapped_device *pool_md,
 bad_endio_hook_pool:
 	mempool_destroy(pool->mapping_pool);
 bad_mapping_pool:
+	dm_deferred_set_destroy(pool->all_io_ds);
+bad_all_io_ds:
+	dm_deferred_set_destroy(pool->shared_read_ds);
+bad_shared_read_ds:
 	destroy_workqueue(pool->wq);
 bad_wq:
 	dm_kcopyd_client_destroy(pool->copier);
 bad_kcopyd_client:
-	prison_destroy(pool->prison);
+	dm_bio_prison_destroy(pool->prison);
 bad_prison:
 	kfree(pool);
 bad_pool:
@@ -2982,7 +3027,7 @@ static int thin_endio(struct dm_target *ti,
 
 	if (h->shared_read_entry) {
 		INIT_LIST_HEAD(&work);
-		ds_dec(h->shared_read_entry, &work);
+		dm_deferred_entry_dec(h->shared_read_entry, &work);
 
 		spin_lock_irqsave(&pool->lock, flags);
 		list_for_each_entry_safe(m, tmp, &work, list) {
@@ -2995,7 +3040,7 @@ static int thin_endio(struct dm_target *ti,
 
 	if (h->all_io_entry) {
 		INIT_LIST_HEAD(&work);
-		ds_dec(h->all_io_entry, &work);
+		dm_deferred_entry_dec(h->all_io_entry, &work);
 		spin_lock_irqsave(&pool->lock, flags);
 		list_for_each_entry_safe(m, tmp, &work, list)
 			list_add(&m->list, &pool->prepared_discards);
@@ -3128,9 +3173,7 @@ static int __init dm_thin_init(void)
 
 	r = -ENOMEM;
 
-	_cell_cache = KMEM_CACHE(dm_bio_prison_cell, 0);
-	if (!_cell_cache)
-		goto bad_cell_cache;
+	dm_bio_prison_init();
 
 	_new_mapping_cache = KMEM_CACHE(dm_thin_new_mapping, 0);
 	if (!_new_mapping_cache)
@@ -3145,8 +3188,6 @@ static int __init dm_thin_init(void)
 bad_endio_hook_cache:
 	kmem_cache_destroy(_new_mapping_cache);
 bad_new_mapping_cache:
-	kmem_cache_destroy(_cell_cache);
-bad_cell_cache:
 	dm_unregister_target(&pool_target);
 bad_pool_target:
 	dm_unregister_target(&thin_target);
@@ -3159,7 +3200,7 @@ static void dm_thin_exit(void)
 	dm_unregister_target(&thin_target);
 	dm_unregister_target(&pool_target);
 
-	kmem_cache_destroy(_cell_cache);
+	dm_bio_prison_exit();
 	kmem_cache_destroy(_new_mapping_cache);
 	kmem_cache_destroy(_endio_hook_cache);
 }