dm: enable request based option
This patch enables request-based dm.
o Request-based dm and bio-based dm coexist, since there are
some target drivers which are more fitting to bio-based dm.
Also, there are other bio-based devices in the kernel
(e.g. md, loop).
Since bio-based device can't receive struct request,
there are some limitations on device stacking between
bio-based and request-based.
type of underlying device
bio-based request-based
----------------------------------------------
bio-based OK OK
request-based -- OK
The device type is recognized by the queue flag in the kernel,
so dm follows that.
o The type of a dm device is decided at the first table binding time.
Once the type of a dm device is decided, the type can't be changed.
o Mempool allocations are deferred to at the table loading time, since
mempools for request-based dm are different from those for bio-based
dm and needed mempool type is fixed by the type of table.
o Currently, request-based dm supports only tables that have a single
target. To support multiple targets, we need to support request
splitting or prevent bio/request from spanning multiple targets.
The former needs lots of changes in the block layer, and the latter
needs that all target drivers support merge() function.
Both will take a time.
Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
hifive-unleashed-5.1
Kiyoshi Ueda
Alasdair G Kergon
parent
cec47e3d4a
commit
e6ee8c0b76
|
|
@ -1050,6 +1050,12 @@ static int populate_table(struct dm_table *table,
|
|||
next = spec->next;
|
||||
}
|
||||
|
||||
r = dm_table_set_type(table);
|
||||
if (r) {
|
||||
DMWARN("unable to set table type");
|
||||
return r;
|
||||
}
|
||||
|
||||
return dm_table_complete(table);
|
||||
}
|
||||
|
||||
|
|
@ -1095,6 +1101,13 @@ static int table_load(struct dm_ioctl *param, size_t param_size)
|
|||
goto out;
|
||||
}
|
||||
|
||||
r = dm_table_alloc_md_mempools(t);
|
||||
if (r) {
|
||||
DMWARN("unable to allocate mempools for this table");
|
||||
dm_table_destroy(t);
|
||||
goto out;
|
||||
}
|
||||
|
||||
down_write(&_hash_lock);
|
||||
hc = dm_get_mdptr(md);
|
||||
if (!hc || hc->md != md) {
|
||||
|
|
|
|||
|
|
@ -41,6 +41,7 @@
|
|||
struct dm_table {
|
||||
struct mapped_device *md;
|
||||
atomic_t holders;
|
||||
unsigned type;
|
||||
|
||||
/* btree table */
|
||||
unsigned int depth;
|
||||
|
|
@ -65,6 +66,8 @@ struct dm_table {
|
|||
/* events get handed up using this callback */
|
||||
void (*event_fn)(void *);
|
||||
void *event_context;
|
||||
|
||||
struct dm_md_mempools *mempools;
|
||||
};
|
||||
|
||||
/*
|
||||
|
|
@ -258,6 +261,8 @@ void dm_table_destroy(struct dm_table *t)
|
|||
if (t->devices.next != &t->devices)
|
||||
free_devices(&t->devices);
|
||||
|
||||
dm_free_md_mempools(t->mempools);
|
||||
|
||||
kfree(t);
|
||||
}
|
||||
|
||||
|
|
@ -764,6 +769,99 @@ int dm_table_add_target(struct dm_table *t, const char *type,
|
|||
return r;
|
||||
}
|
||||
|
||||
int dm_table_set_type(struct dm_table *t)
|
||||
{
|
||||
unsigned i;
|
||||
unsigned bio_based = 0, request_based = 0;
|
||||
struct dm_target *tgt;
|
||||
struct dm_dev_internal *dd;
|
||||
struct list_head *devices;
|
||||
|
||||
for (i = 0; i < t->num_targets; i++) {
|
||||
tgt = t->targets + i;
|
||||
if (dm_target_request_based(tgt))
|
||||
request_based = 1;
|
||||
else
|
||||
bio_based = 1;
|
||||
|
||||
if (bio_based && request_based) {
|
||||
DMWARN("Inconsistent table: different target types"
|
||||
" can't be mixed up");
|
||||
return -EINVAL;
|
||||
}
|
||||
}
|
||||
|
||||
if (bio_based) {
|
||||
/* We must use this table as bio-based */
|
||||
t->type = DM_TYPE_BIO_BASED;
|
||||
return 0;
|
||||
}
|
||||
|
||||
BUG_ON(!request_based); /* No targets in this table */
|
||||
|
||||
/* Non-request-stackable devices can't be used for request-based dm */
|
||||
devices = dm_table_get_devices(t);
|
||||
list_for_each_entry(dd, devices, list) {
|
||||
if (!blk_queue_stackable(bdev_get_queue(dd->dm_dev.bdev))) {
|
||||
DMWARN("table load rejected: including"
|
||||
" non-request-stackable devices");
|
||||
return -EINVAL;
|
||||
}
|
||||
}
|
||||
|
||||
/*
|
||||
* Request-based dm supports only tables that have a single target now.
|
||||
* To support multiple targets, request splitting support is needed,
|
||||
* and that needs lots of changes in the block-layer.
|
||||
* (e.g. request completion process for partial completion.)
|
||||
*/
|
||||
if (t->num_targets > 1) {
|
||||
DMWARN("Request-based dm doesn't support multiple targets yet");
|
||||
return -EINVAL;
|
||||
}
|
||||
|
||||
t->type = DM_TYPE_REQUEST_BASED;
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
unsigned dm_table_get_type(struct dm_table *t)
|
||||
{
|
||||
return t->type;
|
||||
}
|
||||
|
||||
bool dm_table_request_based(struct dm_table *t)
|
||||
{
|
||||
return dm_table_get_type(t) == DM_TYPE_REQUEST_BASED;
|
||||
}
|
||||
|
||||
int dm_table_alloc_md_mempools(struct dm_table *t)
|
||||
{
|
||||
unsigned type = dm_table_get_type(t);
|
||||
|
||||
if (unlikely(type == DM_TYPE_NONE)) {
|
||||
DMWARN("no table type is set, can't allocate mempools");
|
||||
return -EINVAL;
|
||||
}
|
||||
|
||||
t->mempools = dm_alloc_md_mempools(type);
|
||||
if (!t->mempools)
|
||||
return -ENOMEM;
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
void dm_table_free_md_mempools(struct dm_table *t)
|
||||
{
|
||||
dm_free_md_mempools(t->mempools);
|
||||
t->mempools = NULL;
|
||||
}
|
||||
|
||||
struct dm_md_mempools *dm_table_get_md_mempools(struct dm_table *t)
|
||||
{
|
||||
return t->mempools;
|
||||
}
|
||||
|
||||
static int setup_indexes(struct dm_table *t)
|
||||
{
|
||||
int i;
|
||||
|
|
@ -985,6 +1083,19 @@ void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
|
|||
queue_flag_set_unlocked(QUEUE_FLAG_CLUSTER, q);
|
||||
|
||||
dm_table_set_integrity(t);
|
||||
|
||||
/*
|
||||
* QUEUE_FLAG_STACKABLE must be set after all queue settings are
|
||||
* visible to other CPUs because, once the flag is set, incoming bios
|
||||
* are processed by request-based dm, which refers to the queue
|
||||
* settings.
|
||||
* Until the flag set, bios are passed to bio-based dm and queued to
|
||||
* md->deferred where queue settings are not needed yet.
|
||||
* Those bios are passed to request-based dm at the resume time.
|
||||
*/
|
||||
smp_mb();
|
||||
if (dm_table_request_based(t))
|
||||
queue_flag_set_unlocked(QUEUE_FLAG_STACKABLE, q);
|
||||
}
|
||||
|
||||
unsigned int dm_table_get_num_targets(struct dm_table *t)
|
||||
|
|
|
|||
162
drivers/md/dm.c
162
drivers/md/dm.c
|
|
@ -190,6 +190,15 @@ struct mapped_device {
|
|||
struct bio barrier_bio;
|
||||
};
|
||||
|
||||
/*
|
||||
* For mempools pre-allocation at the table loading time.
|
||||
*/
|
||||
struct dm_md_mempools {
|
||||
mempool_t *io_pool;
|
||||
mempool_t *tio_pool;
|
||||
struct bio_set *bs;
|
||||
};
|
||||
|
||||
#define MIN_IOS 256
|
||||
static struct kmem_cache *_io_cache;
|
||||
static struct kmem_cache *_tio_cache;
|
||||
|
|
@ -1739,10 +1748,22 @@ static struct mapped_device *alloc_dev(int minor)
|
|||
INIT_LIST_HEAD(&md->uevent_list);
|
||||
spin_lock_init(&md->uevent_lock);
|
||||
|
||||
md->queue = blk_alloc_queue(GFP_KERNEL);
|
||||
md->queue = blk_init_queue(dm_request_fn, NULL);
|
||||
if (!md->queue)
|
||||
goto bad_queue;
|
||||
|
||||
/*
|
||||
* Request-based dm devices cannot be stacked on top of bio-based dm
|
||||
* devices. The type of this dm device has not been decided yet,
|
||||
* although we initialized the queue using blk_init_queue().
|
||||
* 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);
|
||||
md->saved_make_request_fn = md->queue->make_request_fn;
|
||||
md->queue->queuedata = md;
|
||||
md->queue->backing_dev_info.congested_fn = dm_any_congested;
|
||||
md->queue->backing_dev_info.congested_data = md;
|
||||
|
|
@ -1751,18 +1772,9 @@ static struct mapped_device *alloc_dev(int minor)
|
|||
blk_queue_bounce_limit(md->queue, BLK_BOUNCE_ANY);
|
||||
md->queue->unplug_fn = dm_unplug_all;
|
||||
blk_queue_merge_bvec(md->queue, dm_merge_bvec);
|
||||
|
||||
md->io_pool = mempool_create_slab_pool(MIN_IOS, _io_cache);
|
||||
if (!md->io_pool)
|
||||
goto bad_io_pool;
|
||||
|
||||
md->tio_pool = mempool_create_slab_pool(MIN_IOS, _tio_cache);
|
||||
if (!md->tio_pool)
|
||||
goto bad_tio_pool;
|
||||
|
||||
md->bs = bioset_create(16, 0);
|
||||
if (!md->bs)
|
||||
goto bad_no_bioset;
|
||||
blk_queue_softirq_done(md->queue, dm_softirq_done);
|
||||
blk_queue_prep_rq(md->queue, dm_prep_fn);
|
||||
blk_queue_lld_busy(md->queue, dm_lld_busy);
|
||||
|
||||
md->disk = alloc_disk(1);
|
||||
if (!md->disk)
|
||||
|
|
@ -1804,12 +1816,6 @@ bad_bdev:
|
|||
bad_thread:
|
||||
put_disk(md->disk);
|
||||
bad_disk:
|
||||
bioset_free(md->bs);
|
||||
bad_no_bioset:
|
||||
mempool_destroy(md->tio_pool);
|
||||
bad_tio_pool:
|
||||
mempool_destroy(md->io_pool);
|
||||
bad_io_pool:
|
||||
blk_cleanup_queue(md->queue);
|
||||
bad_queue:
|
||||
free_minor(minor);
|
||||
|
|
@ -1829,9 +1835,12 @@ static void free_dev(struct mapped_device *md)
|
|||
unlock_fs(md);
|
||||
bdput(md->bdev);
|
||||
destroy_workqueue(md->wq);
|
||||
mempool_destroy(md->tio_pool);
|
||||
mempool_destroy(md->io_pool);
|
||||
bioset_free(md->bs);
|
||||
if (md->tio_pool)
|
||||
mempool_destroy(md->tio_pool);
|
||||
if (md->io_pool)
|
||||
mempool_destroy(md->io_pool);
|
||||
if (md->bs)
|
||||
bioset_free(md->bs);
|
||||
blk_integrity_unregister(md->disk);
|
||||
del_gendisk(md->disk);
|
||||
free_minor(minor);
|
||||
|
|
@ -1846,6 +1855,29 @@ static void free_dev(struct mapped_device *md)
|
|||
kfree(md);
|
||||
}
|
||||
|
||||
static void __bind_mempools(struct mapped_device *md, struct dm_table *t)
|
||||
{
|
||||
struct dm_md_mempools *p;
|
||||
|
||||
if (md->io_pool && md->tio_pool && md->bs)
|
||||
/* the md already has necessary mempools */
|
||||
goto out;
|
||||
|
||||
p = dm_table_get_md_mempools(t);
|
||||
BUG_ON(!p || md->io_pool || md->tio_pool || md->bs);
|
||||
|
||||
md->io_pool = p->io_pool;
|
||||
p->io_pool = NULL;
|
||||
md->tio_pool = p->tio_pool;
|
||||
p->tio_pool = NULL;
|
||||
md->bs = p->bs;
|
||||
p->bs = NULL;
|
||||
|
||||
out:
|
||||
/* mempool bind completed, now no need any mempools in the table */
|
||||
dm_table_free_md_mempools(t);
|
||||
}
|
||||
|
||||
/*
|
||||
* Bind a table to the device.
|
||||
*/
|
||||
|
|
@ -1897,6 +1929,18 @@ static int __bind(struct mapped_device *md, struct dm_table *t,
|
|||
|
||||
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) && !blk_queue_stopped(q))
|
||||
stop_queue(q);
|
||||
|
||||
__bind_mempools(md, t);
|
||||
|
||||
write_lock(&md->map_lock);
|
||||
md->map = t;
|
||||
dm_table_set_restrictions(t, q, limits);
|
||||
|
|
@ -2110,10 +2154,14 @@ static void dm_wq_work(struct work_struct *work)
|
|||
|
||||
up_write(&md->io_lock);
|
||||
|
||||
if (bio_barrier(c))
|
||||
process_barrier(md, c);
|
||||
else
|
||||
__split_and_process_bio(md, c);
|
||||
if (dm_request_based(md))
|
||||
generic_make_request(c);
|
||||
else {
|
||||
if (bio_barrier(c))
|
||||
process_barrier(md, c);
|
||||
else
|
||||
__split_and_process_bio(md, c);
|
||||
}
|
||||
|
||||
down_write(&md->io_lock);
|
||||
}
|
||||
|
|
@ -2146,6 +2194,13 @@ int dm_swap_table(struct mapped_device *md, struct dm_table *table)
|
|||
if (r)
|
||||
goto out;
|
||||
|
||||
/* cannot change the device type, once a table is bound */
|
||||
if (md->map &&
|
||||
(dm_table_get_type(md->map) != dm_table_get_type(table))) {
|
||||
DMWARN("can't change the device type after a table is bound");
|
||||
goto out;
|
||||
}
|
||||
|
||||
__unbind(md);
|
||||
r = __bind(md, table, &limits);
|
||||
|
||||
|
|
@ -2542,6 +2597,61 @@ int dm_noflush_suspending(struct dm_target *ti)
|
|||
}
|
||||
EXPORT_SYMBOL_GPL(dm_noflush_suspending);
|
||||
|
||||
struct dm_md_mempools *dm_alloc_md_mempools(unsigned type)
|
||||
{
|
||||
struct dm_md_mempools *pools = kmalloc(sizeof(*pools), GFP_KERNEL);
|
||||
|
||||
if (!pools)
|
||||
return NULL;
|
||||
|
||||
pools->io_pool = (type == DM_TYPE_BIO_BASED) ?
|
||||
mempool_create_slab_pool(MIN_IOS, _io_cache) :
|
||||
mempool_create_slab_pool(MIN_IOS, _rq_bio_info_cache);
|
||||
if (!pools->io_pool)
|
||||
goto free_pools_and_out;
|
||||
|
||||
pools->tio_pool = (type == DM_TYPE_BIO_BASED) ?
|
||||
mempool_create_slab_pool(MIN_IOS, _tio_cache) :
|
||||
mempool_create_slab_pool(MIN_IOS, _rq_tio_cache);
|
||||
if (!pools->tio_pool)
|
||||
goto free_io_pool_and_out;
|
||||
|
||||
pools->bs = (type == DM_TYPE_BIO_BASED) ?
|
||||
bioset_create(16, 0) : bioset_create(MIN_IOS, 0);
|
||||
if (!pools->bs)
|
||||
goto free_tio_pool_and_out;
|
||||
|
||||
return pools;
|
||||
|
||||
free_tio_pool_and_out:
|
||||
mempool_destroy(pools->tio_pool);
|
||||
|
||||
free_io_pool_and_out:
|
||||
mempool_destroy(pools->io_pool);
|
||||
|
||||
free_pools_and_out:
|
||||
kfree(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->tio_pool)
|
||||
mempool_destroy(pools->tio_pool);
|
||||
|
||||
if (pools->bs)
|
||||
bioset_free(pools->bs);
|
||||
|
||||
kfree(pools);
|
||||
}
|
||||
|
||||
static struct block_device_operations dm_blk_dops = {
|
||||
.open = dm_blk_open,
|
||||
.release = dm_blk_close,
|
||||
|
|
|
|||
|
|
@ -22,6 +22,13 @@
|
|||
#define DM_SUSPEND_LOCKFS_FLAG (1 << 0)
|
||||
#define DM_SUSPEND_NOFLUSH_FLAG (1 << 1)
|
||||
|
||||
/*
|
||||
* Type of table and mapped_device's mempool
|
||||
*/
|
||||
#define DM_TYPE_NONE 0
|
||||
#define DM_TYPE_BIO_BASED 1
|
||||
#define DM_TYPE_REQUEST_BASED 2
|
||||
|
||||
/*
|
||||
* List of devices that a metadevice uses and should open/close.
|
||||
*/
|
||||
|
|
@ -32,6 +39,7 @@ struct dm_dev_internal {
|
|||
};
|
||||
|
||||
struct dm_table;
|
||||
struct dm_md_mempools;
|
||||
|
||||
/*-----------------------------------------------------------------
|
||||
* Internal table functions.
|
||||
|
|
@ -51,12 +59,23 @@ void dm_table_postsuspend_targets(struct dm_table *t);
|
|||
int dm_table_resume_targets(struct dm_table *t);
|
||||
int dm_table_any_congested(struct dm_table *t, int bdi_bits);
|
||||
int dm_table_any_busy_target(struct dm_table *t);
|
||||
int dm_table_set_type(struct dm_table *t);
|
||||
unsigned dm_table_get_type(struct dm_table *t);
|
||||
bool dm_table_request_based(struct dm_table *t);
|
||||
int dm_table_alloc_md_mempools(struct dm_table *t);
|
||||
void dm_table_free_md_mempools(struct dm_table *t);
|
||||
struct dm_md_mempools *dm_table_get_md_mempools(struct dm_table *t);
|
||||
|
||||
/*
|
||||
* To check the return value from dm_table_find_target().
|
||||
*/
|
||||
#define dm_target_is_valid(t) ((t)->table)
|
||||
|
||||
/*
|
||||
* To check whether the target type is request-based or not (bio-based).
|
||||
*/
|
||||
#define dm_target_request_based(t) ((t)->type->map_rq != NULL)
|
||||
|
||||
/*-----------------------------------------------------------------
|
||||
* A registry of target types.
|
||||
*---------------------------------------------------------------*/
|
||||
|
|
@ -102,4 +121,10 @@ void dm_kobject_uevent(struct mapped_device *md, enum kobject_action action,
|
|||
int dm_kcopyd_init(void);
|
||||
void dm_kcopyd_exit(void);
|
||||
|
||||
/*
|
||||
* Mempool operations
|
||||
*/
|
||||
struct dm_md_mempools *dm_alloc_md_mempools(unsigned type);
|
||||
void dm_free_md_mempools(struct dm_md_mempools *pools);
|
||||
|
||||
#endif
|
||||
|
|
|
|||
Loading…
Reference in New Issue