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dm: allow immutable request-based targets to use blk-mq pdu

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This will allow DM multipath to use a portion of the blk-mq pdu space
for target data (e.g. struct dm_mpath_io).

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This commit is contained in:
Mike Snitzer 2016-01-31 12:05:42 -05:00
parent 30187e1d48
commit 591ddcfc4b
3 changed files with 28 additions and 9 deletions
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2
drivers/md/dm-ioctl.c
View file

@ -1304,7 +1304,7 @@ static int table_load(struct dm_ioctl *param, size_t param_size)
dm_set_md_type(md, dm_table_get_type(t));
/* setup md->queue to reflect md's type (may block) */
r = dm_setup_md_queue(md);
r = dm_setup_md_queue(md, t);
if (r) {
DMWARN("unable to set up device queue for new table.");
goto err_unlock_md_type;

33
drivers/md/dm.c
View file

@ -224,7 +224,8 @@ struct mapped_device {
/* for blk-mq request-based DM support */
struct blk_mq_tag_set *tag_set;
bool use_blk_mq;
bool use_blk_mq:1;
bool init_tio_pdu:1;
};
#ifdef CONFIG_DM_MQ_DEFAULT
@ -243,6 +244,7 @@ bool dm_use_blk_mq(struct mapped_device *md)
{
return md->use_blk_mq;
}
EXPORT_SYMBOL_GPL(dm_use_blk_mq);
/*
* For mempools pre-allocation at the table loading time.
@ -1889,7 +1891,13 @@ static void init_tio(struct dm_rq_target_io *tio, struct request *rq,
tio->clone = NULL;
tio->orig = rq;
tio->error = 0;
memset(&tio->info, 0, sizeof(tio->info));
/*
* Avoid initializing info for blk-mq; it passes
* target-specific data through info.ptr
* (see: dm_mq_init_request)
*/
if (!md->init_tio_pdu)
memset(&tio->info, 0, sizeof(tio->info));
if (md->kworker_task)
init_kthread_work(&tio->work, map_tio_request);
}
@ -2313,6 +2321,7 @@ static struct mapped_device *alloc_dev(int minor)
goto bad_io_barrier;
md->use_blk_mq = use_blk_mq;
md->init_tio_pdu = false;
md->type = DM_TYPE_NONE;
mutex_init(&md->suspend_lock);
mutex_init(&md->type_lock);
@ -2653,6 +2662,11 @@ static int dm_mq_init_request(void *data, struct request *rq,
*/
tio->md = md;
if (md->init_tio_pdu) {
/* target-specific per-io data is immediately after the tio */
tio->info.ptr = tio + 1;
}
return 0;
}
@ -2704,7 +2718,8 @@ static struct blk_mq_ops dm_mq_ops = {
.init_request = dm_mq_init_request,
};
static int dm_mq_init_request_queue(struct mapped_device *md)
static int dm_mq_init_request_queue(struct mapped_device *md,
struct dm_target *immutable_tgt)
{
struct request_queue *q;
int err;
@ -2726,6 +2741,11 @@ static int dm_mq_init_request_queue(struct mapped_device *md)
md->tag_set->driver_data = md;
md->tag_set->cmd_size = sizeof(struct dm_rq_target_io);
if (immutable_tgt && immutable_tgt->per_io_data_size) {
/* any target-specific per-io data is immediately after the tio */
md->tag_set->cmd_size += immutable_tgt->per_io_data_size;
md->init_tio_pdu = true;
}
err = blk_mq_alloc_tag_set(md->tag_set);
if (err)
@ -2763,7 +2783,7 @@ static unsigned filter_md_type(unsigned type, struct mapped_device *md)
/*
* Setup the DM device's queue based on md's type
*/
int dm_setup_md_queue(struct mapped_device *md)
int dm_setup_md_queue(struct mapped_device *md, struct dm_table *t)
{
int r;
unsigned md_type = filter_md_type(dm_get_md_type(md), md);
@ -2777,7 +2797,7 @@ int dm_setup_md_queue(struct mapped_device *md)
}
break;
case DM_TYPE_MQ_REQUEST_BASED:
r = dm_mq_init_request_queue(md);
r = dm_mq_init_request_queue(md, dm_table_get_immutable_target(t));
if (r) {
DMERR("Cannot initialize queue for request-based dm-mq mapped device");
return r;
@ -3505,8 +3525,7 @@ struct dm_md_mempools *dm_alloc_md_mempools(struct mapped_device *md, unsigned t
if (!pool_size)
pool_size = dm_get_reserved_rq_based_ios();
front_pad = offsetof(struct dm_rq_clone_bio_info, clone);
/* per_io_data_size is not used. */
WARN_ON(per_io_data_size != 0);
/* per_io_data_size is used for blk-mq pdu at queue allocation */
break;
default:
BUG();

2
drivers/md/dm.h
View file

@ -86,7 +86,7 @@ void dm_set_md_type(struct mapped_device *md, unsigned type);
unsigned dm_get_md_type(struct mapped_device *md);
struct target_type *dm_get_immutable_target_type(struct mapped_device *md);
int dm_setup_md_queue(struct mapped_device *md);
int dm_setup_md_queue(struct mapped_device *md, struct dm_table *t);
/*
* To check the return value from dm_table_find_target().