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>
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index df20a11..22a22a7 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 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 @@
* @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 @@
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 @@
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 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 @@
*
* 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 @@
*/
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 @@
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 @@
__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_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 @@
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 @@
* 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 @@
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 @@
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 @@
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 @@
/*
* 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 @@
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_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 @@
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 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 @@
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 @@
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 @@
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 @@
{
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
* 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 @@
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 @@
* 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 @@
/*
* 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 @@
default:
DMERR("%s: alloc_data_block() failed, error = %d", __func__, r);
- cell_error(cell);
+ dm_cell_error(cell);
break;
}
}
@@ -1395,14 +1422,14 @@
{
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 @@
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 @@
* 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 @@
*/
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 @@
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 @@
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 @@
* 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 @@
* 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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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);
}