Commit e83068a5 authored by Mike Snitzer's avatar Mike Snitzer

dm mpath: add optional "queue_mode" feature

Allow a user to specify an optional feature 'queue_mode <mode>' where
<mode> may be "bio", "rq" or "mq" -- which corresponds to bio-based,
request_fn rq-based, and blk-mq rq-based respectively.

If the queue_mode feature isn't specified the default for the
"multipath" target is still "rq" but if dm_mod.use_blk_mq is set to Y
it'll default to mode "mq".

This new queue_mode feature introduces the ability for each multipath
device to have its own queue_mode (whereas before this feature all
multipath devices effectively had to have the same queue_mode).

This commit also goes a long way to eliminate the awkward (ab)use of
DM_TYPE_*, the associated filter_md_type() and other relatively fragile
and difficult to maintain code.
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent bf661be1
......@@ -90,6 +90,8 @@ struct multipath {
atomic_t pg_init_in_progress; /* Only one pg_init allowed at once */
atomic_t pg_init_count; /* Number of times pg_init called */
unsigned queue_mode;
/*
* We must use a mempool of dm_mpath_io structs so that we
* can resubmit bios on error.
......@@ -131,7 +133,6 @@ static void process_queued_bios(struct work_struct *work);
#define MPATHF_PG_INIT_DISABLED 4 /* pg_init is not currently allowed */
#define MPATHF_PG_INIT_REQUIRED 5 /* pg_init needs calling? */
#define MPATHF_PG_INIT_DELAY_RETRY 6 /* Delay pg_init retry? */
#define MPATHF_BIO_BASED 7 /* Device is bio-based? */
/*-----------------------------------------------
* Allocation routines
......@@ -191,8 +192,7 @@ static void free_priority_group(struct priority_group *pg,
kfree(pg);
}
static struct multipath *alloc_multipath(struct dm_target *ti, bool use_blk_mq,
bool bio_based)
static struct multipath *alloc_multipath(struct dm_target *ti)
{
struct multipath *m;
......@@ -210,19 +210,36 @@ static struct multipath *alloc_multipath(struct dm_target *ti, bool use_blk_mq,
mutex_init(&m->work_mutex);
m->mpio_pool = NULL;
if (!use_blk_mq && !bio_based) {
unsigned min_ios = dm_get_reserved_rq_based_ios();
m->queue_mode = DM_TYPE_NONE;
m->mpio_pool = mempool_create_slab_pool(min_ios, _mpio_cache);
if (!m->mpio_pool) {
kfree(m);
return NULL;
m->ti = ti;
ti->private = m;
}
return m;
}
static int alloc_multipath_stage2(struct dm_target *ti, struct multipath *m)
{
if (m->queue_mode == DM_TYPE_NONE) {
/*
* Default to request-based.
*/
if (dm_use_blk_mq(dm_table_get_md(ti->table)))
m->queue_mode = DM_TYPE_MQ_REQUEST_BASED;
else
m->queue_mode = DM_TYPE_REQUEST_BASED;
}
if (bio_based) {
if (m->queue_mode == DM_TYPE_REQUEST_BASED) {
unsigned min_ios = dm_get_reserved_rq_based_ios();
m->mpio_pool = mempool_create_slab_pool(min_ios, _mpio_cache);
if (!m->mpio_pool)
return -ENOMEM;
}
else if (m->queue_mode == DM_TYPE_BIO_BASED) {
INIT_WORK(&m->process_queued_bios, process_queued_bios);
set_bit(MPATHF_BIO_BASED, &m->flags);
/*
* bio-based doesn't support any direct scsi_dh management;
* it just discovers if a scsi_dh is attached.
......@@ -230,11 +247,9 @@ static struct multipath *alloc_multipath(struct dm_target *ti, bool use_blk_mq,
set_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, &m->flags);
}
m->ti = ti;
ti->private = m;
}
dm_table_set_type(ti->table, m->queue_mode);
return m;
return 0;
}
static void free_multipath(struct multipath *m)
......@@ -653,7 +668,7 @@ static int multipath_map_bio(struct dm_target *ti, struct bio *bio)
static void process_queued_bios_list(struct multipath *m)
{
if (test_bit(MPATHF_BIO_BASED, &m->flags))
if (m->queue_mode == DM_TYPE_BIO_BASED)
queue_work(kmultipathd, &m->process_queued_bios);
}
......@@ -964,7 +979,7 @@ static int parse_hw_handler(struct dm_arg_set *as, struct multipath *m)
if (!hw_argc)
return 0;
if (test_bit(MPATHF_BIO_BASED, &m->flags)) {
if (m->queue_mode == DM_TYPE_BIO_BASED) {
dm_consume_args(as, hw_argc);
DMERR("bio-based multipath doesn't allow hardware handler args");
return 0;
......@@ -1005,7 +1020,7 @@ static int parse_features(struct dm_arg_set *as, struct multipath *m)
const char *arg_name;
static struct dm_arg _args[] = {
{0, 6, "invalid number of feature args"},
{0, 8, "invalid number of feature args"},
{1, 50, "pg_init_retries must be between 1 and 50"},
{0, 60000, "pg_init_delay_msecs must be between 0 and 60000"},
};
......@@ -1045,6 +1060,24 @@ static int parse_features(struct dm_arg_set *as, struct multipath *m)
continue;
}
if (!strcasecmp(arg_name, "queue_mode") &&
(argc >= 1)) {
const char *queue_mode_name = dm_shift_arg(as);
if (!strcasecmp(queue_mode_name, "bio"))
m->queue_mode = DM_TYPE_BIO_BASED;
else if (!strcasecmp(queue_mode_name, "rq"))
m->queue_mode = DM_TYPE_REQUEST_BASED;
else if (!strcasecmp(queue_mode_name, "mq"))
m->queue_mode = DM_TYPE_MQ_REQUEST_BASED;
else {
ti->error = "Unknown 'queue_mode' requested";
r = -EINVAL;
}
argc--;
continue;
}
ti->error = "Unrecognised multipath feature request";
r = -EINVAL;
} while (argc && !r);
......@@ -1052,8 +1085,7 @@ static int parse_features(struct dm_arg_set *as, struct multipath *m)
return r;
}
static int __multipath_ctr(struct dm_target *ti, unsigned int argc,
char **argv, bool bio_based)
static int multipath_ctr(struct dm_target *ti, unsigned argc, char **argv)
{
/* target arguments */
static struct dm_arg _args[] = {
......@@ -1066,12 +1098,11 @@ static int __multipath_ctr(struct dm_target *ti, unsigned int argc,
struct dm_arg_set as;
unsigned pg_count = 0;
unsigned next_pg_num;
bool use_blk_mq = dm_use_blk_mq(dm_table_get_md(ti->table));
as.argc = argc;
as.argv = argv;
m = alloc_multipath(ti, use_blk_mq, bio_based);
m = alloc_multipath(ti);
if (!m) {
ti->error = "can't allocate multipath";
return -EINVAL;
......@@ -1081,6 +1112,10 @@ static int __multipath_ctr(struct dm_target *ti, unsigned int argc,
if (r)
goto bad;
r = alloc_multipath_stage2(ti, m);
if (r)
goto bad;
r = parse_hw_handler(&as, m);
if (r)
goto bad;
......@@ -1130,9 +1165,9 @@ static int __multipath_ctr(struct dm_target *ti, unsigned int argc,
ti->num_flush_bios = 1;
ti->num_discard_bios = 1;
ti->num_write_same_bios = 1;
if (bio_based)
if (m->queue_mode == DM_TYPE_BIO_BASED)
ti->per_io_data_size = multipath_per_bio_data_size();
else if (use_blk_mq)
else if (m->queue_mode == DM_TYPE_MQ_REQUEST_BASED)
ti->per_io_data_size = sizeof(struct dm_mpath_io);
return 0;
......@@ -1142,16 +1177,6 @@ static int __multipath_ctr(struct dm_target *ti, unsigned int argc,
return r;
}
static int multipath_ctr(struct dm_target *ti, unsigned argc, char **argv)
{
return __multipath_ctr(ti, argc, argv, false);
}
static int multipath_bio_ctr(struct dm_target *ti, unsigned argc, char **argv)
{
return __multipath_ctr(ti, argc, argv, true);
}
static void multipath_wait_for_pg_init_completion(struct multipath *m)
{
DECLARE_WAITQUEUE(wait, current);
......@@ -1700,7 +1725,9 @@ static void multipath_status(struct dm_target *ti, status_type_t type,
DMEMIT("%u ", test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags) +
(m->pg_init_retries > 0) * 2 +
(m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT) * 2 +
test_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, &m->flags));
test_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, &m->flags) +
(m->queue_mode != DM_TYPE_REQUEST_BASED) * 2);
if (test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags))
DMEMIT("queue_if_no_path ");
if (m->pg_init_retries)
......@@ -1709,6 +1736,16 @@ static void multipath_status(struct dm_target *ti, status_type_t type,
DMEMIT("pg_init_delay_msecs %u ", m->pg_init_delay_msecs);
if (test_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, &m->flags))
DMEMIT("retain_attached_hw_handler ");
if (m->queue_mode != DM_TYPE_REQUEST_BASED) {
switch(m->queue_mode) {
case DM_TYPE_BIO_BASED:
DMEMIT("queue_mode bio ");
break;
case DM_TYPE_MQ_REQUEST_BASED:
DMEMIT("queue_mode mq ");
break;
}
}
}
if (!m->hw_handler_name || type == STATUSTYPE_INFO)
......@@ -1995,7 +2032,7 @@ static int multipath_busy(struct dm_target *ti)
*---------------------------------------------------------------*/
static struct target_type multipath_target = {
.name = "multipath",
.version = {1, 11, 0},
.version = {1, 12, 0},
.features = DM_TARGET_SINGLETON | DM_TARGET_IMMUTABLE,
.module = THIS_MODULE,
.ctr = multipath_ctr,
......@@ -2004,22 +2041,6 @@ static struct target_type multipath_target = {
.clone_and_map_rq = multipath_clone_and_map,
.release_clone_rq = multipath_release_clone,
.rq_end_io = multipath_end_io,
.presuspend = multipath_presuspend,
.postsuspend = multipath_postsuspend,
.resume = multipath_resume,
.status = multipath_status,
.message = multipath_message,
.prepare_ioctl = multipath_prepare_ioctl,
.iterate_devices = multipath_iterate_devices,
.busy = multipath_busy,
};
static struct target_type multipath_bio_target = {
.name = "multipath-bio",
.version = {1, 0, 0},
.module = THIS_MODULE,
.ctr = multipath_bio_ctr,
.dtr = multipath_dtr,
.map = multipath_map_bio,
.end_io = multipath_end_io_bio,
.presuspend = multipath_presuspend,
......@@ -2048,13 +2069,6 @@ static int __init dm_multipath_init(void)
goto bad_register_target;
}
r = dm_register_target(&multipath_bio_target);
if (r < 0) {
DMERR("bio-based register failed %d", r);
r = -EINVAL;
goto bad_register_bio_based_target;
}
kmultipathd = alloc_workqueue("kmpathd", WQ_MEM_RECLAIM, 0);
if (!kmultipathd) {
DMERR("failed to create workqueue kmpathd");
......@@ -2081,8 +2095,6 @@ static int __init dm_multipath_init(void)
bad_alloc_kmpath_handlerd:
destroy_workqueue(kmultipathd);
bad_alloc_kmultipathd:
dm_unregister_target(&multipath_bio_target);
bad_register_bio_based_target:
dm_unregister_target(&multipath_target);
bad_register_target:
kmem_cache_destroy(_mpio_cache);
......@@ -2096,7 +2108,6 @@ static void __exit dm_multipath_exit(void)
destroy_workqueue(kmultipathd);
dm_unregister_target(&multipath_target);
dm_unregister_target(&multipath_bio_target);
kmem_cache_destroy(_mpio_cache);
}
......
......@@ -230,7 +230,14 @@ static void free_rq_clone(struct request *clone)
blk_rq_unprep_clone(clone);
if (md->type == DM_TYPE_MQ_REQUEST_BASED)
/*
* It is possible for a clone_old_rq() allocated clone to
* get passed in -- it may not yet have a request_queue.
* This is known to occur if the error target replaces
* a multipath target that has a request_fn queue stacked
* on blk-mq queue(s).
*/
if (clone->q && clone->q->mq_ops)
/* stacked on blk-mq queue(s) */
tio->ti->type->release_clone_rq(clone);
else if (!md->queue->mq_ops)
......@@ -561,7 +568,7 @@ static struct dm_rq_target_io *dm_old_prep_tio(struct request *rq,
* Must clone a request if this .request_fn DM device
* is stacked on .request_fn device(s).
*/
if (!dm_table_mq_request_based(table)) {
if (!dm_table_all_blk_mq_devices(table)) {
if (!clone_old_rq(rq, md, tio, gfp_mask)) {
dm_put_live_table(md, srcu_idx);
free_old_rq_tio(tio);
......@@ -711,7 +718,7 @@ ssize_t dm_attr_rq_based_seq_io_merge_deadline_store(struct mapped_device *md,
{
unsigned deadline;
if (!dm_request_based(md) || md->use_blk_mq)
if (dm_get_md_type(md) != DM_TYPE_REQUEST_BASED)
return count;
if (kstrtouint(buf, 10, &deadline))
......@@ -886,12 +893,13 @@ static struct blk_mq_ops dm_mq_ops = {
.init_request = dm_mq_init_request,
};
int dm_mq_init_request_queue(struct mapped_device *md, struct dm_target *immutable_tgt)
int dm_mq_init_request_queue(struct mapped_device *md, struct dm_table *t)
{
struct request_queue *q;
struct dm_target *immutable_tgt;
int err;
if (dm_get_md_type(md) == DM_TYPE_REQUEST_BASED) {
if (!dm_table_all_blk_mq_devices(t)) {
DMERR("request-based dm-mq may only be stacked on blk-mq device(s)");
return -EINVAL;
}
......@@ -908,6 +916,7 @@ int dm_mq_init_request_queue(struct mapped_device *md, struct dm_target *immutab
md->tag_set->driver_data = md;
md->tag_set->cmd_size = sizeof(struct dm_rq_target_io);
immutable_tgt = dm_table_get_immutable_target(t);
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;
......
......@@ -49,7 +49,7 @@ bool dm_use_blk_mq_default(void);
bool dm_use_blk_mq(struct mapped_device *md);
int dm_old_init_request_queue(struct mapped_device *md);
int dm_mq_init_request_queue(struct mapped_device *md, struct dm_target *immutable_tgt);
int dm_mq_init_request_queue(struct mapped_device *md, struct dm_table *t);
void dm_mq_cleanup_mapped_device(struct mapped_device *md);
void dm_start_queue(struct request_queue *q);
......
......@@ -43,8 +43,10 @@ struct dm_table {
struct dm_target *targets;
struct target_type *immutable_target_type;
unsigned integrity_supported:1;
unsigned singleton:1;
bool integrity_supported:1;
bool singleton:1;
bool all_blk_mq:1;
/*
* Indicates the rw permissions for the new logical
......@@ -206,6 +208,7 @@ int dm_table_create(struct dm_table **result, fmode_t mode,
return -ENOMEM;
}
t->type = DM_TYPE_NONE;
t->mode = mode;
t->md = md;
*result = t;
......@@ -703,7 +706,7 @@ int dm_table_add_target(struct dm_table *t, const char *type,
dm_device_name(t->md), type);
return -EINVAL;
}
t->singleton = 1;
t->singleton = true;
}
if (dm_target_always_writeable(tgt->type) && !(t->mode & FMODE_WRITE)) {
......@@ -830,16 +833,29 @@ static bool __table_type_request_based(unsigned table_type)
table_type == DM_TYPE_MQ_REQUEST_BASED);
}
static int dm_table_set_type(struct dm_table *t)
void dm_table_set_type(struct dm_table *t, unsigned type)
{
t->type = type;
}
EXPORT_SYMBOL_GPL(dm_table_set_type);
static int dm_table_determine_type(struct dm_table *t)
{
unsigned i;
unsigned bio_based = 0, request_based = 0, hybrid = 0;
bool use_blk_mq = false;
bool verify_blk_mq = false;
struct dm_target *tgt;
struct dm_dev_internal *dd;
struct list_head *devices;
struct list_head *devices = dm_table_get_devices(t);
unsigned live_md_type = dm_get_md_type(t->md);
if (t->type != DM_TYPE_NONE) {
/* target already set the table's type */
if (t->type == DM_TYPE_BIO_BASED)
return 0;
goto verify_rq_based;
}
for (i = 0; i < t->num_targets; i++) {
tgt = t->targets + i;
if (dm_target_hybrid(tgt))
......@@ -876,6 +892,19 @@ static int dm_table_set_type(struct dm_table *t)
BUG_ON(!request_based); /* No targets in this table */
if (list_empty(devices) && __table_type_request_based(live_md_type)) {
/* inherit live MD type */
t->type = live_md_type;
return 0;
}
/*
* The only way to establish DM_TYPE_MQ_REQUEST_BASED is by
* having a compatible target use dm_table_set_type.
*/
t->type = DM_TYPE_REQUEST_BASED;
verify_rq_based:
/*
* Request-based dm supports only tables that have a single target now.
* To support multiple targets, request splitting support is needed,
......@@ -888,7 +917,6 @@ static int dm_table_set_type(struct dm_table *t)
}
/* 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) {
struct request_queue *q = bdev_get_queue(dd->dm_dev->bdev);
......@@ -899,10 +927,10 @@ static int dm_table_set_type(struct dm_table *t)
}
if (q->mq_ops)
use_blk_mq = true;
verify_blk_mq = true;
}
if (use_blk_mq) {
if (verify_blk_mq) {
/* verify _all_ devices in the table are blk-mq devices */
list_for_each_entry(dd, devices, list)
if (!bdev_get_queue(dd->dm_dev->bdev)->mq_ops) {
......@@ -910,14 +938,9 @@ static int dm_table_set_type(struct dm_table *t)
" are blk-mq request-stackable");
return -EINVAL;
}
t->type = DM_TYPE_MQ_REQUEST_BASED;
} else if (list_empty(devices) && __table_type_request_based(live_md_type)) {
/* inherit live MD type */
t->type = live_md_type;
} else
t->type = DM_TYPE_REQUEST_BASED;
t->all_blk_mq = true;
}
return 0;
}
......@@ -961,9 +984,9 @@ bool dm_table_request_based(struct dm_table *t)
return __table_type_request_based(dm_table_get_type(t));
}
bool dm_table_mq_request_based(struct dm_table *t)
bool dm_table_all_blk_mq_devices(struct dm_table *t)
{
return dm_table_get_type(t) == DM_TYPE_MQ_REQUEST_BASED;
return t->all_blk_mq;
}
static int dm_table_alloc_md_mempools(struct dm_table *t, struct mapped_device *md)
......@@ -1106,7 +1129,7 @@ static int dm_table_register_integrity(struct dm_table *t)
return 0;
if (!integrity_profile_exists(dm_disk(md))) {
t->integrity_supported = 1;
t->integrity_supported = true;
/*
* Register integrity profile during table load; we can do
* this because the final profile must match during resume.
......@@ -1129,7 +1152,7 @@ static int dm_table_register_integrity(struct dm_table *t)
}
/* Preserve existing integrity profile */
t->integrity_supported = 1;
t->integrity_supported = true;
return 0;
}
......@@ -1141,9 +1164,9 @@ int dm_table_complete(struct dm_table *t)
{
int r;
r = dm_table_set_type(t);
r = dm_table_determine_type(t);
if (r) {
DMERR("unable to set table type");
DMERR("unable to determine table type");
return r;
}
......
......@@ -1738,23 +1738,14 @@ struct queue_limits *dm_get_queue_limits(struct mapped_device *md)
}
EXPORT_SYMBOL_GPL(dm_get_queue_limits);
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, struct dm_table *t)
{
int r;
unsigned md_type = filter_md_type(dm_get_md_type(md), md);
switch (md_type) {
switch (dm_get_md_type(md)) {
case DM_TYPE_REQUEST_BASED:
r = dm_old_init_request_queue(md);
if (r) {
......@@ -1763,7 +1754,7 @@ int dm_setup_md_queue(struct mapped_device *md, struct dm_table *t)
}
break;
case DM_TYPE_MQ_REQUEST_BASED:
r = dm_mq_init_request_queue(md, dm_table_get_immutable_target(t));
r = dm_mq_init_request_queue(md, t);
if (r) {
DMERR("Cannot initialize queue for request-based dm-mq mapped device");
return r;
......@@ -2472,8 +2463,6 @@ struct dm_md_mempools *dm_alloc_md_mempools(struct mapped_device *md, unsigned t
if (!pools)
return NULL;
type = filter_md_type(type, md);
switch (type) {
case DM_TYPE_BIO_BASED:
cachep = _io_cache;
......
......@@ -33,14 +33,6 @@
*/
#define DM_STATUS_NOFLUSH_FLAG (1 << 0)
/*
* 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
#define DM_TYPE_MQ_REQUEST_BASED 3
/*
* List of devices that a metadevice uses and should open/close.
*/
......@@ -77,7 +69,7 @@ struct target_type *dm_table_get_immutable_target_type(struct dm_table *t);
struct dm_target *dm_table_get_immutable_target(struct dm_table *t);
struct dm_target *dm_table_get_wildcard_target(struct dm_table *t);
bool dm_table_request_based(struct dm_table *t);
bool dm_table_mq_request_based(struct dm_table *t);
bool dm_table_all_blk_mq_devices(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);
......
......@@ -19,6 +19,14 @@ struct dm_table;
struct mapped_device;
struct bio_vec;
/*
* Type of table, mapped_device's mempool and request_queue
*/
#define DM_TYPE_NONE 0
#define DM_TYPE_BIO_BASED 1
#define DM_TYPE_REQUEST_BASED 2
#define DM_TYPE_MQ_REQUEST_BASED 3
typedef enum { STATUSTYPE_INFO, STATUSTYPE_TABLE } status_type_t;
union map_info {
......@@ -443,6 +451,14 @@ int dm_table_add_target(struct dm_table *t, const char *type,
*/
void dm_table_add_target_callbacks(struct dm_table *t, struct dm_target_callbacks *cb);
/*
* Target can use this to set the table's type.
* Can only ever be called from a target's ctr.
* Useful for "hybrid" target (supports both bio-based
* and request-based).
*/
void dm_table_set_type(struct dm_table *t, unsigned type);
/*
* Finally call this to make the table ready for use.
*/
......
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